Abnormalities of Zinc and Copper During Total Parenteral Nutrition STEPHEN F. LOWRY, M.D.,* J. THOMAS GOODGAME, JR., M.D.,* J. CECIL SMITH, JR., PHD.,4 MICHELLE M. MAHER, R.N.,* ROBERT W. MAKUCH, PH.D.,t ROBERT 1. HENKIN, M.D.,§ MURRAY F. BRENNAN, M.D.*
From the Surgery Branch and Biostatistics Division, National Cancer Institute, National Institutes of Health, Bethesda, Maryland; the Trace Element Research Laboratory, Washington Veteran's Administration Hospital; and the Center for Molecular Nutrition and Sensory Disorders Georgetown University Medical Center, Washington, D.C.
Changes in serum zinc and copper levels were studied in 19 tumor bearing patients undergoing parenteral nutrition (TPN) for five to 42 days. Before initiation of intravenous feeding mean serum zinc and copper concentrations were within normal limits but during TPN levels decreased significantly below those measured prior to parenteral nutrition. During TPN nitrogen, zinc, and copper intake, urinary output and serum levels were studied prospectively in nine of these patients. These nine patients exhibited positive nitrogen retention based upon urinary nitrogen excretion, but elevated urinary zinc and copper excretion and lowered serum zinc and copper concentrations. Neither blood administration nor limited oral intake was consistently able to maintain normal serum levels of zinc or copper. Zinc and copper supplementation of hyperalimentation fluids in four patients studied for five to 16 days was successful in increasing serum zinc and copper levels in only two. The data obtained suggest that patients undergoing parenteral nutrition may require supplementation of zinc and copper to prevent deficiencies of these elements.
chexia. While it has been suggested that TPN may be of significant benefit for this population, systematic studies of trace element requirements have not been reported. These problems are magnified by the common assumption that trace element needs during TPN are met by transfusions of blood products9 or small amounts or oral liquids, presumably contaminated with zinc and copper. Any attempt to supplement parenteral nutrition regimens with zinc and copper is complicated by the present lack of patient data regarding such requirements during TPN.A2 The present study examines prospectively the changes in zinc, copper, and nitrogen metabolism in patients undergoing parenteral nutrition.
A CUTE AND CHRONIC REDUCTIONS in plasma
or serum, zinc 1.12,19.28.44 and copper12'19'27'44'50 have been increasingly apparent in patients undergoing total parenteral nutrition (TPN). These observations have largely been limited to patients with primary diseases of the gastrointestinal tract in whom preceeding malabsorptive or inflammatory illness were implicated as causative factors in trace element deficiencies. Parenteral nutrition has also assumed a prominent supportive role for patients with malignancy in whom oral nutrition is restricted by antitumor therapy, organic obstruction of the gastrointestinal tract and/or ca-
Materials and Methods
* Surgery Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland. t Biostatistics Division, National Cancer Institute, National Institutes of Health, Bethesda, Maryland. t Trace Elements Research Laboratory, Washington VA Hospital, Washington, D.C. § Center for Molecular Nutrition and Sensory Disorders, Georgetown University Medical Center, Washington, D.C. Reprint requests: Murray F. Brennan, M.D., National Institutes of Health, Building 10, Room lON116, Bethesda, Maryland. 20014. Submitted for publication: December 12, 1977.
Parenteral Nutrition Regimen Parenteral nutrition was provided through a polyethylene catheter placed percutaneously into the superior vena cava. All patients received a solution of 25% dextrose and 4.25% Fre-Amine II* which had been prepared under sterile laminar flow conditions in the pharmacy, Clinical Center, National Institutes of Health. Supplemental vitamins and electrolytes were added to the solution as necessary. No heat sterilization of the combined amino acid and dextrose solution was done, and the final filtering of the solution was made through a 0.22 micron millipore filter. *
McGaw Laboratories, Glendale, CA.
0003-4932/79/0100/0120 $00.95 © J. B. Lippincott Company
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ZINC AND COPPER DURING TPN
Serum An initial sample of blood was taken through the polyethylene catheter at the time of insertion. Samples were immediately placed into trace metal free plastic tubes and within one hour of collection, were centrifuged at 3000 rpm for 15 minutes. Serum was removed, placed in trace metal free plastic tubes and frozen at 40 until time of assay. All transfers were made with acid washed glassware. Additional samples were obtained at intervals shown subsequently and all were handled in the same fashion. Urine All urine was collected over periods of 24 hours in plastic receptacles containing 10-20 ml of concentrated (12 M) trace metal free hydrochloric acid.t After measurement of urinary volume, an aliquot was placed in a trace metal free plastic tube and kept at 40 until assayed for zinc and copper. An additional aliquot was collected in the same manner for measurement of total nitrogen by the micro-kjeldahl technique.
Parenteral Nutrition Solution Prior to final filtering, 5 ml samples were withdrawn from bottles of parenteral nutrition solution and placed in plastic trace metal free tubes for assay of zinc, copper and nitrogen. Determination of Zinc and Copper Concentrations of serum zinc and copper were determined by flame aspiration atomic absorption spectrophotometry by two methods. In one method, samples were measured in a Model 403 Perkin-Elmer Atomic Absorption Spectrophotometert with reference standards diluted in glycerol;7 in the other method samples were measured in a Model 251 Instrumentation Laboratory Atomic Absorption Spectrophotometer§ with serum and standards diluted with butanol.3 Concentrations of zinc and copper in urine were determined by standard procedures.7 3 No systematic differences were observed among the results obtained by either method used.
Statistical Analysis Data for serum zinc and copper were analyzed for statistical trends by an analysis of variance for single factor experiments having repeated measurements.51 t J. T. Baker Chemical Co., Phillipsburg, NJ. t Perkin-Elmer Corp., Norwalk, Connecticut. § Instrumentatia Laboratory, Lexington, Massachusetts.
121 Means and standard errors of the mean for serum and urinary trace metal and urinary nitrogen excretion were also determined for each condition studied and analyzed by Student's t-test for unpaired data, while weekly changes in serum zinc and copper were also analyzed by the method of comparison for paired results. Results
Patient Population
Nineteen patients undergoing total parenteral nutrition during therapy for malignancy were studied (Table 1). Patients ranged in age from 12 to 63 years. The mean preillness weight of the patients was 63.6 + 3.3 g, (mean + 1 SEM); while it was 50.6 + 2.4 g at the time of initiation of intravenous feeding, indicating a mean loss of 18.9 + 3.2% from preillness weight. The time since cessation of "normal" oral intake ranged from two to 44 weeks (mean = 10 + 3 weeks) before the onset of parenteral nutrition. Only three of the patients had any diarrhea prior to initiation of TPN. Nine of the 19 subjects had undergone surgery within two weeks prior to initiation of TPN. Four patients had been treated for clinical sepsis immediately prior to the start of parenteral nutrition, but non exhibited sepsis during the period of evaluation. Eleven patients had bulk tumor (estimated greater than 1% of total body weight) present during the time of TPN support. Patients were permitted oral intake, usually of clear liquids, as tolerated by the clinical circumstances. Decisions for blood replacement were based upon clinical indications and no attempt was made to administer these products on a regular basis. In patients who received trace metal supplementation, the decision to do so was made empirically prior to knowledge of serum or urinary levels. Serum Zinc and Copper Changes Changes in serum zinc and copper concentrations for the entire patient group are shown in Table 1 and in Figures 1 and 2. Although the initial mean level of serum zinc was within normal limits it was below the normal mean (92 + 2 ug/dl) in 12 of the 19 patients (Table 1). For the entire group over the course of parenteral feeding mean serum zinc concentration fell to levels significantly (p < 0.01) below those measured prior to TPN and below normal levels as well. Reduction of serum zinc concentration was noted in 13 of 19 patients while six exhibited either an increased or unchanged concentration. Two of these patients received blood products during their parenteral feeding course. During the course of TPN serum zinc concentrations were below the lower limits of the normal range in 17 patients, the levels having been within normal limits in
122
Ann. Surg. * January 1979
LOWRY AND OTHERS TABLE 1. Zinc, Copper and Nitrogen Metabolism During Total Parenteral Nutrition
Total Blood Products Given Patient (Sex-Age)
Clinical Status
1. RH(M-31) 2. MG(F-33) 3. TP(M-47) 4. BD(F-52) 5. JL(M-50)
P,S,II P,S,II II III S,II
MR(F-56) TW(M- 12) RB(F-63) CW(F-49) JP(M-56) ND(M-21) CM(F-62) LM(M-46) EJ(F-63) AS(F-17) HW(F-51) JB(M-61) 18. LK(M-55) 19. TZ(M-28) Mean + 1 SEM Normal (,ug/dl)
S,IV P,II I III IV P,IV P,III P,III P,III II P,II IV IV P,IV
6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17.
(ml)
Type
0 0 700 1220 1000 2045 0 0 0 0 560 1500 590 0 0 0 0 0 0 2000
RC RC WB RC
RC RL WB
WB
Serum Values
(Agldl)
Daily Urinary Excretion
(fig/day)
During TPN
Days Studied on TPN
Zn
Cu
Zn
Cu
5 6 16 26 20
80 100 140 65 100
72 126 182 134 76
85 85 85 65 75
50 74 82 62 78
45 45 105 60 55 130 76 35 30 55 32 60 40 85
32 58 54 44 144 62 76 94 114 102 60 82 62 122
22 36 7 27 21 8 11 8 18 29 8 28 42 16 19 ±+3
Pre-TPN
82 60 144 85 125 54 55 54 170 85 70 64 62 40 80 110 75 184 70 168 54 36 135 94 125 88 125 128 88 + 7 106 11 66 2 92 ± 2 106
+
6*t 76
+
7*t
Zn
Cu
1962 99 2780 253 266 18 3305 100 842 66 535 100 251 97 1360 77 4378 149 1742 490* 107 22* 333 23 36± 5
N1.
- Nur. (gms)
3.22 0.03 7.13 3.27 0.61 0.14 3.81 3.72 3.80 2.85 ± 0.75
* p < 0.01 with respect to control values. t p < 0.01 with respect to pretreatment values. Clinical status: P-Post-operative within two weeks of initiating TPN; S-Septic documented prior to initiating TPN; I-No detectable tumor present; II-Tumor burden estimated 5% of body weight. Blood products: RC-packed red blood cells; WB-fresh whole blood; PL-fresh plasma.
six of these patients prior to parenteral feeding (Fig. 1). In general, the longer the period of TPN administration, the greater the decrease in serum zinc concentration. However, a statistically significant decrease (p < 0.01)
lir-
was noted after two weeks of TPN by analysis of variance and after three weeks (p < 0.02) by paired t-test. Although the initial mean serum copper concentration for the entire patient group was not different from 140 V
in I
it. z
F
it. F
MV
NH
U3 HF~ i
W. 161
4SF
aSF 201-
0
0
4-10
il-l7
18-24
25-31 0
DAYS OF TPN
FIG. 1. Serum zinc concentrations before and during TPN. Ordinate, serum zinc concentration in ,ug/dl; abscissa, days after initiation of TPN. Normal serum zinc level is 92 2 ,ug/dl. X SEM (n = number of observations during indicated time period). ±
±
4-10
11-17
18-24
25.31
DAY OF TPN FIG. 2. Change in serum copper levels relative to pre-TPN values. Normal serum copper level is 106 + 2 ,ug/dl. X ± SEM (n = number of observations during indicated time period).
Vol. 189.9 NO. 125 100
.4 I
weeks while paired t-test revealed a significant (p < 0.02) decrease after three weeks of parenteral
o zinc *
feeding.
Is
75 F
soF
§
25 F
0
(n=9)
123
ZINC AND COPPER DURING TPN
I
(n=6) DAYS OF TPN
(n=9)
(n=9)
7
14
(n-3)
28
21
FIG. 3. Serial changes in serum zinc and copper levels for patients studied with concurrent urinary nitrogen balance and trace metal excretion. See Table 2 for urinary levels. X + SEM (n = number of patients studied at time indicated).
normal, 10 patients were observed to have serum copper concentrations below the normal mean (106 + 2 ug/dl) prior to undergoing TPN (Table 1). Ten patients exhibited a fall of serum copper concentration greater than 20 ug/dl during the course of TPN, four having been normal prior to the initiation of parenteral feeding. Only two patients exhibited an increase in serum copper concentration during their treatment and both of these patients received blood products during this period. As with serum zinc, in general, the longer the period of TPN administration, the greater the decrease in serum copper concentration. However, analysis of variance indicated a slight, but not statistically significant decrease in serum copper (0.10 < p > 0.05) after two
Considering the entire patient group, no correlation was observed between changes in serum zinc or copper concentration and administration of blood products. The mean daily oral consumption, in all cases less than one liter per day, also could not be correlated with changes in serum levels of these trace elements. Urinary Zinc, Copper, and Nitrogen Studies
Nine of the patients underwent concurrent evaluation of urinary zinc and copper excretion and nitrogen loss (Table 1). Fecal and fistulous losses were not analyzed, but in no case did the volume of fistula loss exceed 200 ml per day, and no patient with diarrhea was included. Based upon comparison of urinary nitrogen excretion and total nitrogen intake, all patients exhibited positive nitrogen retention. Weekly changes in serum zinc and copper for this latter group are shown in Figure 3. Although the downward trends in both zinc and copper concentrations were observed as in the data from the whole group, analysis of variance for changes in zinc (f = 1.05) or copper (f = 1.64) were not statistically significant at any period examined. These results may be related to the small number of patients comprising the study group.
Mean daily urinary excretion of zinc and copper in this group is shown for each week in Table 2. Excretion
TABLE 2. Urinary Excretion of Zinc, Copper and Nitrogen During Total Parenteral Nutrition
Entire Group Daily urinary metal excretion (,ug/24 hr): Zinc Copper Nitrogen balance*
(gm/24 hr) Postoperative Daily urinary metal excretion (,tgl24 hr): Zinc
Copper Nitrogen balance* (gm/24 hr) Non-operative Daily urinary metal excretion (,ug/24 hr): Zinc Copper Nitrogen balance* (gm/24 hr) * Total daily nitrogen intake
-
Week 1
Week 2
Week 3
Week 4
Week 5
(Days 1-7)
(Days 8-14)
(Days 15-21)
(Days 22-28)
(Days 29-35)
(9)
(9)
(6)
(3)
(2)
1792 ± 530 102 21
1903 ± 393 117 24
1607 ± 765 94 8
413 ± 114 56 15
4.05 ± 1.00
3.20 ± 0.83
4.15 ± 0.60
1.19 ± 3.20
(6)
(6)
(3)
1829 ± 476 108 + 31
2414 ± 839 128 + 34
2672 ± 1076 105 ± 3
2.83 ± 1.09
3.28 + 1.13
3.38 ± 1.58
(3)
(3)
(3)
(3)
1718 ± 1247 89± 22
882 + 402 93 25
894 ± 390 93 ± 25
413 ± 114 56 ± 15
6.49 ± 1.29
3.03 + 1.37
4.65 ± 0.15
4.72 ± 1.52
total daily urinary nitrogen excretion (n); x + SEM.
709 60 2.17
(2) 709 60
2.17
124
of both metals was above the normal range (333 + 23 ug/day for zinc, 36 + 5 ug/day for copper) following one to three weeks of TPN, but excretion decreased four and five weeks after continued TPN at a time when serum zinc and copper concentrations were consistently low. If these nine patients are evaluated with respect to recent operative status, an initially lower value of serum zinc is seen in the six recently operated patients (74 vs 110 ug/da). After three weeks of TPN, however, both groups had low serum zinc and copper concentrations. Six of these patients consistently excreted more than 1 ml of urinary zinc per day; five were in the postoperative period and one was undergoing abdominal irradiation for lymphoma. However, when the operative and non-operative groups were analyzed separately for urinary zinc excretion, no significant differences were noted. Urinary nitrogen balances likewise were not different between the two groups (Table 2). Mean daily oral intakes were not different between these groups, although the postoperative subjects consistently had a lower oral intake. Trace Metal Replacement Four additional patients, chosen for assumed susceptibility to acute trace metal deficiency because of weight loss and restricted oral intake prior to TPN, received a formulated trace metal solution (TMS) containing zinc (2.0 mg/ml), copper (0.4 mg/ml), manganese (0.2 mg/ml), and iodine (0.5 mg/ml). At the time of administration of this solution, values of serum zinc and copper were not known. 1801
120
_a. 100 100
FIG. 4. Response of individual patient levels of serum zinc to supplement intravenous zinc. X ± SEM.
u
z
D
cr
Ann. Surg. * January 1979
LOWRY AND OTHERS
80
Un
60 MEAN DAILY IV ZINC
40
o
0
a
1.57 mg/day
A
2.67 mg/day
4
8 12 DAYS OF TPN
160 140
120 7
z 100
FIG. 5. Response ofindividual patient levels of serum copper to supplement intravenous copper. X + SEM.
0
U, en
E 80
60 u6
MEAN DAILY IV COPPER
40
o 0.06
mg/day
e 0.07 mg/day
20
A 0.29 mg,day A 0.53 mg day
4
12 8 DAYS OF TPN
16
Serum responsiveness to this replacement is shown in Figures 4 and 5. Two patients exhibited a marked increase in serum zinc concentration whereas two patients exhibited a slight decline in serum levels. Serum copper concentration increased slightly in two patients, while it decreased in the other two. These changes could not be correlated with the amount of either zinc or copper added to the hyperalimentation solutions. Concurrent examination of urinary zinc and copper excretion was not changed from those reported for the entire group. No differences in urinary excretion of zinc and copper were noted on days these patients received trace metal supplementation compared to days when they did not receive the trace metal solution.
Analysis of Parenteral Nutrition Solutions Assay of zinc and copper from several parenteral nutrition solutions (n = 11) used in this study revealed that one liter contained 430 + 50 Ag of zinc (range 200-800 ,ug/L) and 23 Ag of copper (range 20-30 ,ug/L). Whereas minor variations occur among individual bottles, consistently small amounts of both zinc and copper were observed, regardless of supplementations with vitamin complexes. Discussion
0.29 mg/day
* 0.33 mg/day
20
180
16
While guidelines for maintenance of adequate zinc and copper nutrition are available for the general population39 there is, as yet, little information about zinc and copper requirements in patients undergoing parenteral feeding. Among several groups of patients
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ZINC AND COPPER DURING TPN
with moderate to severe malnutrition reductions in serum concentrations of zinc1' 12"9'28 and copper19'27'50 are being recognized more frequently both before and during any course of TPN. Prior to undergoing TPN, patients with various forms of malignancy have been reported to exhibit lower than normal levels of serum the association of this change with zinc, although 8th specific tumor types has not been clearly established.43 In our study, lower than normal levels of serum zinc were found prior to parenteral feeding in 12 of the 19 patients studied. It has also been suggested that many patients suffering from severe stress may be at risk of zinc deficiency.40 Acute decreases in serum zinc concentrations have been noted in adults subjected to a wide variety of stressful conditions16'30 and in children with protein calorie malnutrition.40 Markedly subnormal serum zinc concentration has been reported following major surgical procedures"' and in response to intravenous12'28 or oral34 refeeding. During TPN the patients in our study exhibited decreased serum levels of both zinc and copper and increased urinary excretion of both of these trace elements. While these findings have been previously observed by several groups of investigators with increasing frequency, the etiology for this reduction is unclear. Several suggestions have been put forward to explain these phenomena. Decreased blood zinc levels have been reported to occur following use of heat sterilized parenteral nutrition solutions presumably related to glucosamine complexes which can bind with zinc in serum and permit increased renal excretion.'3 This mechanism cannot apply in the present study because solutions were prepared without heat sterilization and filtered appropriately. Other investigators speculated that body zinc could be redistributed during TPN as acute and chronic tissue injury and repair occurs. 17 The details of this proposed etiology have not been reported. Decreased blood levels of both zinc and copper and increased urinary zinc and copper excretion has been reported in patients and normal volunteers given moderate to large amounts of L-histidine orally.21 These changes in blood and urine have also been associated with loss of total body zinc and copper. These changes were based upon in vitro studies in which amino acids, particularly histidine and cysteine, were shown to strip zinc21'38 from albumin, its major serum carrying protein. Similar changes were also observed for copper21 but to a lesser degree due to the relatively smaller amount of serum copper bound to albumin and therefore the smaller amount of copper available for transfer to amino acids. Since the principal form of urinary zinc and copper is that bound to amino acids, formation of histidyl and cystinyl zinc and copper complexes in blood is associated with increased
125
amounts of these species appearing in the urine.20 Indeed, this was the case, although histidine was not identified as the causitive agent, in previous studies during parenteral feeding.49 Further studies have suggested that the decreased serum zinc concentrations following TPN may be related to the infusion of L rather than to D forms of amino acids since infusion of D-L amino acids produced less zinc loss than infusion of L-amino acids alone.48 On the basis of the data collected, this hypothesis seems useful to describe the changes observed during TPN. In addition, interrelationships between blood albumin concentration and levels of blood amino acids are also important in determining blood and subsequently urinary zinc and copper levels. Any significant decrease in blood albumin concentration, which commonly occurs in patients with malignancy and with malnutrition, would also tend to magnify the decreased blood zinc and copper levels following intravenous histidine infusion and the increased urinary zinc and copper excretion. Changes in urinary zinc excretion during TPN may be reflective of several concurrent physiological and pathological conditions. Increased urinary zinc loss has been commonly observed following major surgical procedures with'5 and without28 TPN. However, studies during TPN have reported both elevated'5'28'49 and normal45 urinary zinc levels. In our studies after four weeks of TPN both urinary zinc and copper excretion decreased to levels not significantly different from normal. Thus, excretion of urinary zinc and copper must be related to the length of intravenous feeding as well as to the previous total body concentration of the trace metals. Relationships between blood and urinary concentrations of zinc and copper should also be based upon similar considerations. Findings of lowered blood zinc and elevated urinary zinc excretion have been previously noted in several disease states.22'28 Decreased urinary zinc excretion alone has been considered suggestive of zinc deficiency,36 particularly if the deficiency is profound and of long standing. Changes in blood zinc may or may not be reflected by changes in urinary zinc excretion depending again upon several physiological and pathological interrelationships. For example, excessive loss of zinc and copper in urine was not reflected in lowered levels of blood zinc or copper in
hyperparathyroidism.31 These complex interrelationships indicate that identification of zinc deficiency, per se, may not necessarily be a simple task. The symptoms associated with zinc deficiency may be either profound or vague. In acute zinc depletion anorexia, taste and smell dysfunction, cerebellar dysfunction, hyperparakeratosis of the skin and toxic psychosis have been observed.22 In more
126
LOWRY AND OTHERS
chronic zinc deficiency in children in the U.S., anorexia, taste loss and growth retardation have been observed20 and in adults, some manifestations of hypogonadism may also occur.36 However, marginal zinc deficiency has also been observed with few specific complaints.40 As noted above, blood and urine zinc levels provide only partial information about body zinc status. Hair zinc can provide information about chronic zinc depletion,46 while tests of taste acuity have also been useful in diagnosing zinc depletion, on both an acute and chronic basis.22'23 Decreased taste acuity was noted by us in a previous patient with proven zinc deficiency32 and Van Rij reported hypogeusia in a patient with well documented zinc deficiency following TPN.48 In this latter patient, administration of zinc completely reversed all the symptoms of the deficiency. Therapeutic methods for reversal of chronic or acute zinc deficiency have utilized 40-80 mg of intravenous or up to 220 mg of oral zinc sulphate.28 While these levels are far in excess of that required for normal daily balance, there does not appear to be significant toxicity to zinc unless given in massive (gram) doses.2'35 It is important to point out that the commonly held tenet that periodic infusions of fresh plasma or blood products will maintain adequate levels of body zinc appears unfounded in view of our present data. As yet, no study to support this widely held assumption has appeared. Based upon a previously formulated trace metal solution,42 replacement with as much as 1.6 mg of zinc given intravenously daily for 16 days was not adequate to increase blood zinc levels. Patients in whom limited oral intake is possible were similarly not maintained while consuming liquids presumably contaminated with zinc. Daily consumption of 500 to 700 ml of clear liquids in our study was accompanied by decreases in serum zinc levels. Serum copper concentrations are usually stable in individual patients and are observed to be below normal only in rare cases.27'29 Because copper deficiencies previously appeared to be unusual, some have recommended that replacement during TPN was unnecessary.25 As experience with total intravenous feeding has accumulated, however, cases of severe copper deficiency have been reported in children27 and adults.10'50 In addition, longitudinal studies during parenteral feeding have shown decreases in blood copper over the course of therapy.1'12'19 The results of this study also indicate a consistent decline in serum copper in patients undergoing TPN for one to five weeks. While it is not possible, based upon our data or those of others to identify the time course
Ann. Surg. * January 1979
over which the classical hematologic findings of copper deficiency appear, it would seem reasonable to assume that several weeks may be sufficient in previously malnourished patients. Defective absorption of iron in copper deficient animals may have relevance to the concurrent appearance of a microcytic, hypochromic anemia which may mask the true etiology.29 Improvement in anemia may be noted with iron administration, but depression of leukocyte counts is not affected.50 Measurement of ceruloplasmin levels may allow some prediction of potential for copper deficiency.12 Obviously patients undergoing aggressive chemotherapy are often anemic and neutropenic and interpretation of findings is therefore difficult. Levels of urinary copper excretion observed in these patients are two to four times the normal range.3'6 As with zinc, urinary copper is principally complexed with animo acids, and elevated urinary copper excretion observed in this study may reflect the stripping of blood copper from albumin with subsequent excretion in the urine.4'20 The nephrotic syndrome, Wilson's disease,5 acute liver disease,24 or Menkes steely hair disease14 have been associated with excessive urinary copper excretion. None of the patients reported here exhibited evidence of these pathological conditions. In the small group of patients who received a mean dose of 0.25 mg/day of parenteral copper replacement over 11 days, serum copper levels continued to fall by approximately 10 ug/dl. Previously suggested parenteral replacement levels have varied from 0.4 to 1.0 mg/ day. Studies are currently being conducted to determine the efficacy of such dosages in maintaining serum copper levels during intravenous feeding. It is apparent that concurrent blood product replacement is insufficient to maintain copper levels in these patients as would be expected from known levels in these fluids.'8 Excessive loss of zinc and copper is possible through fecal or intestinal fistula routes. While this mechanism has not been examined in our study, it would seem unlikely that this was a significant factor in our patients because intestinal losses were uniformly less than 200 ml per day. It should also be noted that during the period of study no patient reported here developed clinical symptoms that could be directly attributed to deficiency of either zinc or copper. Two patients exhibited serum zinc levels less than 40 ug/dl during TPN; one patient developed a plasma copper level below 40 ug/dl. While acute deficiency syndromes are now recognized for both elements, these clinical manifestations are variable and not necessarily correlated with blood metal
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ZINC AND COPPER DURING TPN
levels. The possibility that tissue stores may enable serum levels to be maintained at marginally low levels for sustained periods before the onset of acute deficiency symptoms is suggested from these and other
13.
data. 12,28,44
14.
Restricted intake associated with chronic loss of trace metals appears to be the most overt cause for reductions of zinc and copper concentrations during parenteral feeding. Levels of zinc and copper present in intravenous18'26 and parenteral nutrition12'44 solutions measured by others and ourselves are certainly insufficient to provide minimal requirements of these elements. It is also apparent that neither blood products nor limited oral intake are adequate to maintain zinc and copper concentrations in most patients. A trace element replacement regimen would appear to represent an important adjunct to the care of patients during parenteral nutrition.
15. 16. 17.
18. 19.
20. 21.
Acknowledgments The authors acknowledge the excellent technical assistance of Mrs. Catherine Gorschboth, Ms. Mary Patricia Howard, and Mr. Daniel C. Jones. Mr. Richard E. Davis, IV Additive Service, Clinical Center Pharmacy, and Mr. George E. Grimes, Pharmaceutical Development Service provided invaluable assistance with formulation of parenteral nutrition solutions.
23.
References
25.
1. Arakawa, T., Tamura, T., Igarashi, Y., et al.: Zinc Deficiency in Two Infants During Total Parenteral Alimentation for Diarrhea. Am. J. Clin. Nutr., 29:197, 1976. 2. Brocks, A., Reid, H. and Glazer, G.: Acute Intravenous Zinc Poisoning. Br. Med. J., 1:1390, 1977. 3. Butler, E. J. and Newman, G. E.: Urinary Excretion of Copper and its Concentrations in Blood of Normal Human Adults. J. Clin. Pathol., 9:157, 1956. 4. Cartwright, G. E., Gubler, C. J. and Wintrobe, M. M.: Studies on Copper Metabolism XI Copper and Iron Metabolism in Nephrotic Syndrome. J. Clin. Invest., 33:685, 1954. 5. Cartwright, G. E., Hodges, R. E., Gubler, C. J., et al.: Studies on Copper Metabolism XIII. Hepatolenticular Degeneration. J. Clin. Invest., 33:1487, 1954. 6. Cartwright, G. E. and Wintrobe, M. M.: Copper Metabolism in Normal Subjects. Am. J. Clin. Nutr., 14:224, 1964. 7. Clinical Methods for Atomic Absorption Spectroscopy, PerkinElmer Corp., Norwalk, Connecticut, 1971. 8. Davies, I. J. T., Musa, M. and Dormandy, T. L.: Measurements of Plasma Zinc II. In Malignant Disease. J. Clin. Pathol., 21:363, 1968. 9. Duke, J. H. and Dudrick, S. J.: Parenteral feeding. In Ballinger, W. F., Collins, J. A., Drucker, W. R., Dudrick, S. J., and Zeppa, R. (eds.) Manual of Surgical Nutrition. Philadelphia, Saunders, 1975. 10. Dunlap, W. M., James, G. W. and Hume, D. M.: Anemia and Neutropenia Caused by Copper Deficiency. Ann. Intern. Med., 80:470, 1974. 11. Fell, G. S., Cuthbertson, D. P., Morrison, C., et al.: Urinary Zinc Levels as an Indication of Muscle Catabolism. Lancet, 1:280, 1973. 12. Fleming, C. R., Hodges, R. E. and Hurley, L. S.: A Prospective
26.
22.
24.
27.
28. 29. 30. 31.
32.
33.
34. 35. 36.
127
Study of Serum Copper and Zinc Levels in Patients Receiving Total Parenteral Nutrition. Am. J. Clin. Nutr., 29:70, 1976. Freeman, J. B., Stegink, L. D., Meyer, P. D., et al.: Excessive Urinary Zinc Losses During Parenteral Alimentation. J. Surg. Res., 18:463, 1975. Garnica, A. D. and Fletcher, S. R.: Parenteral Copper in Menkes' Kinky-hair Syndrome. Lancet, 2:659, 1975. Guthrie, B. E. and Van Rij, A. M.: Short-term Zinc Balance During Intravenous Alimentation. Proc. Univ. Otago Med. Sch., 53:7, 1975. Halstead, J. A. and Smith, J. C., Jr.: Plasma Zinc in Health and Disease. Lancet, 1:322, 1970. Halstead, J. A., Smith, J. C., Jr. and Irwin, M. I.: A Conspectus of Research on Zinc Requirements of Man. J. Nutr., 104: 345, 1974. Handbook of Biological Data, National Academy of Science, National Research Council, Spector, W. S. (ed.) Philadelphia, W. B. Saunders, 1952, p. 408. Hankins, D. A., Riella, M. C., Scribner, B. H. and Bragg, A. L.: Whole Blood Trace Element Concentrations During Total Parenteral Nutrition. Surgery, 79:674, 1976. Hambidge, K. M., Hambidge, C., Jacobs, M. and Baum, J. D.: Low Levels of Zinc in Hair, Anorexia, Poor Growth and Hypogeusia in Children. Pediatr. Res., 6:868, 1972. Henkin, R. I.: Metal-albumin-amino acid interactions: chemical and physiological inter relationships, In M. Friedman, (ed.) Protein-Metal Interactions, New York, Plenum Publishing Co., 1973. Henkin, R. I., Patten, B. M., Re, P. K. and Bronzert, D. A.: A Syndrome of Acute Zinc Loss. Arch. Neurol., 32:745, 1975. Henkin, R. I., Schelter, P. J., Hoye, R. and Mattern, C. F. T.: Idiopathic Hypogeusia with Dysgeusia, Hyposmia and Dysosmia. A New Syndrome. JAMA, 217:434, 1971. Henkin, R. I. and Smith, F. R.: Zinc and Copper Metabolism in Acute Viral Hepatitis. Am. J. Med. Sci., 264:401, 1972. James, B. E. and MacMahon, R. A.: Trace Elements in Intravenous Fluids. Med. J. Aust., 2:1161, 1970. Jetton, M. S., Sullivan, J. F. and Burch, R. E.: Trace Element Contamination of Intravenous Solutions. Arch. Intern. Med., 136:782, 1976. Karpel, J. T. and Peden, V. H.: Copper Deficiency in Long Term Parenteral Nutrition. J. Pediatr., 80:32, 1972. Kay, R. G., Tasman-Jones, C., Pybus, J., et al.: A Syndrome of Acute Zinc Deficiency During Total Parenteral Nutrition in Man. Ann. Surg., 183:331, 1976. Lahey, M. E., Gubler, C. J., Cartwright, G. E. and Wintrobe, M. M.: Studies on Copper Metabolism VI. Blood Copper in Normal Human Subjects. J. Clin. Invest., 32:322, 1953. Lindeman, R. D., Bottomley, R. G., Cornelison, R. L. and Jacobs, L. A.: Influence of Acute Tissue Injury on Zinc Metabolism in Man. J. Lab. Clin. Med., 79:452, 1972. Malette, L. E. and Henkin, R. I.: Altered Copper and Zinc Metabolism in Primary Hyperparathyroidism. Am. J. Med. Sci., 272:167, 1976. McCarthy, D. M., Waldmann, T. A., Brennan, M. F. and Strober, W.: Enteropathy in Selective IgA Deficiency: Immunopathology and Treatment with Cyclophosphamide. Gastroenterology, 70:5, 917 (abstr.), 1976. Meret, S. and Henkin, R. I.: Simultaneous Direct Estimation by Atomic Absorption Spectrophotometry of Copper and Zinc in Serum, Urine and Cerebrospinal Fluid. Clin. Chem., 17: 369, 1971. Moynahan, E. J. and Barnes, P. M.: Zinc Deficiency and a Synthetic Diet for Lactose Intolerance. Lancet, 1:676, 1973. Murphy, J. V.: Intoxication Following Ingestion of Elemental Zinc. JAMA, 212:2119, 1970. Prasad, A. S.: Metabolism of zinc and its deficiency in human subjects. In Prasad, A. S. (ed.) Zinc Metabolism, Springfield, Charles C Thomas, 1966.
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37. Prasad, A. S., Schoomaker, E. B., Ortega, J., et al.: Role of zinc in man and its deficiency in sickle cell disease. pp. 603614; In Brewer, (ed.) Erythrocyte Structure and Function, G. J. New York Alan R. Liss, Inc., 1975. 38. Prasad, A. S. and Oberleas, D.: Binding of Zinc to Amino Acids and Serum Proteins in Vitro. J. Lab. Clin. Med., 76:416, 1970. 39. Recommended Dietary Allowances, Eighth Edition. Food and Nutrition Board, National Research Council, National Academy of Science, Washington, D.C., 1974. 40. Sandstead, H. H.: Zinc Nutrition in the United States. Am. J. Clin. Nutr., 26, 1251, 1973. 41. Sandstead, H. H., Shukry, A. S., Prasad, A. S., et al.: Kwashioknor in Egypt. I Clinical and Biochemical Studies with Special Reference to Plasma Zinc and Serum Lactic Dehydrogenase. Am. J. Clin. Nutr., 17:15, 1965. 42. Shils, M. E.: Guidelines for Total Parenteral Nutrition. JAMA, 220:1721, 1972. 43. Smith, J. C., Jr., Hansen, H. H., Howard, M. P., et al.: Plasma Zinc Concentration in Patients with Bronchogenic Cancer. Lancet, 2:1323, 1971. 44. Solomons, N. W., Layden, T. J., Rosenberg, I. H., et al.: Plasma Trace Metals During Total Parenteral Nutrition. Gastroenterology, 70:1022, 1976.
Ann.
Surg. * January 1979
45. Solomons, N., Vo-Khactu, K., Layden, T., et al.: Plasma Trace Metal Dynamics During Total Parenteral Alimentation. Am. J. Clin. Nutr., 28:421, (abstr.) 1975. 46. Strain, W. H., Steadman, C. T., Lankau, C. A., Jr., et al.: Analysis of Zinc Levels in Hair for the Diagnosis of Zinc Deficiency in Man. J. Lab. Clin. Med., 68:244, 1966. 47. Vallee, B. L., Wacker, W. E. C., Bartholomay, A. F. and Hoch, F. L.: Zinc Metabolism in Hepatic Dysfunction. Ann. Intern. Med., 50:1077, 1959. 48. Van Rij, A. M. and McKenzie, J. M.: Hyperzincuria and zinc deficiency. In Kuichgemer, M. (ed.) Total Parenteral Nutrition. T.E.M.A. III, (in press, 1977). 49. Van Rij, A. M., McKenzie, J. M. and Dunckley, J. V.: Excessive Urinary Zinc Losses and Amino Aciduria During Intravenous Alimentation. Proc. Univ. Otago Med. Sch., 53:77, 1975. 50. Vilter, R. W., Bozian, R. C., Hess, E. V., et al.: Manifestations of Copper Deficiency in a Patient with Systemic Sclerosis on Intravenous Hyperalimentation. N. Engl. J. Med., 291:188, 1974. 51. Winer, B. J.: Statistical Principles in Experimental Design. New York, McGraw-Hill Company, 1962. 52. Wretlind, A.: Complete Intravenous Nutrition: Theoretical and Experimental Background. Nutr. Metab., 14 (suppl.), p. 51, 1972.
Announcement The appearance of the code at the bottom of the first page of an article in this journal indicates the copyright owner's consent that copies of the article may be made for personal or internal use, or for personal or internal use of specific clients. This consent is given on the condition, however, that the copier pay the stated per-copy fee through the Copyright Clearance Center Inc., P.O. Box 765, Schenectady, N.Y. 12301, for copying beyond that permitted by Sections 107 or 108 of the U.S. Copyright Law. This consent does not extend to other kinds of copying, such as copying for general distribution, for advertising or promotional purposes, for creating new collective works, or for resale.
From the Surgery Branch and Biostatistics Division, National Cancer Institute, National Institutes of Health, Bethesda, Maryland; the Trace Element Research Laboratory, Washington Veteran's Administration Hospital; and the Center for Molecular Nutrition and Sensory Disorders Georgetown University Medical Center, Washington, D.C.
Changes in serum zinc and copper levels were studied in 19 tumor bearing patients undergoing parenteral nutrition (TPN) for five to 42 days. Before initiation of intravenous feeding mean serum zinc and copper concentrations were within normal limits but during TPN levels decreased significantly below those measured prior to parenteral nutrition. During TPN nitrogen, zinc, and copper intake, urinary output and serum levels were studied prospectively in nine of these patients. These nine patients exhibited positive nitrogen retention based upon urinary nitrogen excretion, but elevated urinary zinc and copper excretion and lowered serum zinc and copper concentrations. Neither blood administration nor limited oral intake was consistently able to maintain normal serum levels of zinc or copper. Zinc and copper supplementation of hyperalimentation fluids in four patients studied for five to 16 days was successful in increasing serum zinc and copper levels in only two. The data obtained suggest that patients undergoing parenteral nutrition may require supplementation of zinc and copper to prevent deficiencies of these elements.
chexia. While it has been suggested that TPN may be of significant benefit for this population, systematic studies of trace element requirements have not been reported. These problems are magnified by the common assumption that trace element needs during TPN are met by transfusions of blood products9 or small amounts or oral liquids, presumably contaminated with zinc and copper. Any attempt to supplement parenteral nutrition regimens with zinc and copper is complicated by the present lack of patient data regarding such requirements during TPN.A2 The present study examines prospectively the changes in zinc, copper, and nitrogen metabolism in patients undergoing parenteral nutrition.
A CUTE AND CHRONIC REDUCTIONS in plasma
or serum, zinc 1.12,19.28.44 and copper12'19'27'44'50 have been increasingly apparent in patients undergoing total parenteral nutrition (TPN). These observations have largely been limited to patients with primary diseases of the gastrointestinal tract in whom preceeding malabsorptive or inflammatory illness were implicated as causative factors in trace element deficiencies. Parenteral nutrition has also assumed a prominent supportive role for patients with malignancy in whom oral nutrition is restricted by antitumor therapy, organic obstruction of the gastrointestinal tract and/or ca-
Materials and Methods
* Surgery Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland. t Biostatistics Division, National Cancer Institute, National Institutes of Health, Bethesda, Maryland. t Trace Elements Research Laboratory, Washington VA Hospital, Washington, D.C. § Center for Molecular Nutrition and Sensory Disorders, Georgetown University Medical Center, Washington, D.C. Reprint requests: Murray F. Brennan, M.D., National Institutes of Health, Building 10, Room lON116, Bethesda, Maryland. 20014. Submitted for publication: December 12, 1977.
Parenteral Nutrition Regimen Parenteral nutrition was provided through a polyethylene catheter placed percutaneously into the superior vena cava. All patients received a solution of 25% dextrose and 4.25% Fre-Amine II* which had been prepared under sterile laminar flow conditions in the pharmacy, Clinical Center, National Institutes of Health. Supplemental vitamins and electrolytes were added to the solution as necessary. No heat sterilization of the combined amino acid and dextrose solution was done, and the final filtering of the solution was made through a 0.22 micron millipore filter. *
McGaw Laboratories, Glendale, CA.
0003-4932/79/0100/0120 $00.95 © J. B. Lippincott Company
120
Vol. 189.9 No. I
ZINC AND COPPER DURING TPN
Serum An initial sample of blood was taken through the polyethylene catheter at the time of insertion. Samples were immediately placed into trace metal free plastic tubes and within one hour of collection, were centrifuged at 3000 rpm for 15 minutes. Serum was removed, placed in trace metal free plastic tubes and frozen at 40 until time of assay. All transfers were made with acid washed glassware. Additional samples were obtained at intervals shown subsequently and all were handled in the same fashion. Urine All urine was collected over periods of 24 hours in plastic receptacles containing 10-20 ml of concentrated (12 M) trace metal free hydrochloric acid.t After measurement of urinary volume, an aliquot was placed in a trace metal free plastic tube and kept at 40 until assayed for zinc and copper. An additional aliquot was collected in the same manner for measurement of total nitrogen by the micro-kjeldahl technique.
Parenteral Nutrition Solution Prior to final filtering, 5 ml samples were withdrawn from bottles of parenteral nutrition solution and placed in plastic trace metal free tubes for assay of zinc, copper and nitrogen. Determination of Zinc and Copper Concentrations of serum zinc and copper were determined by flame aspiration atomic absorption spectrophotometry by two methods. In one method, samples were measured in a Model 403 Perkin-Elmer Atomic Absorption Spectrophotometert with reference standards diluted in glycerol;7 in the other method samples were measured in a Model 251 Instrumentation Laboratory Atomic Absorption Spectrophotometer§ with serum and standards diluted with butanol.3 Concentrations of zinc and copper in urine were determined by standard procedures.7 3 No systematic differences were observed among the results obtained by either method used.
Statistical Analysis Data for serum zinc and copper were analyzed for statistical trends by an analysis of variance for single factor experiments having repeated measurements.51 t J. T. Baker Chemical Co., Phillipsburg, NJ. t Perkin-Elmer Corp., Norwalk, Connecticut. § Instrumentatia Laboratory, Lexington, Massachusetts.
121 Means and standard errors of the mean for serum and urinary trace metal and urinary nitrogen excretion were also determined for each condition studied and analyzed by Student's t-test for unpaired data, while weekly changes in serum zinc and copper were also analyzed by the method of comparison for paired results. Results
Patient Population
Nineteen patients undergoing total parenteral nutrition during therapy for malignancy were studied (Table 1). Patients ranged in age from 12 to 63 years. The mean preillness weight of the patients was 63.6 + 3.3 g, (mean + 1 SEM); while it was 50.6 + 2.4 g at the time of initiation of intravenous feeding, indicating a mean loss of 18.9 + 3.2% from preillness weight. The time since cessation of "normal" oral intake ranged from two to 44 weeks (mean = 10 + 3 weeks) before the onset of parenteral nutrition. Only three of the patients had any diarrhea prior to initiation of TPN. Nine of the 19 subjects had undergone surgery within two weeks prior to initiation of TPN. Four patients had been treated for clinical sepsis immediately prior to the start of parenteral nutrition, but non exhibited sepsis during the period of evaluation. Eleven patients had bulk tumor (estimated greater than 1% of total body weight) present during the time of TPN support. Patients were permitted oral intake, usually of clear liquids, as tolerated by the clinical circumstances. Decisions for blood replacement were based upon clinical indications and no attempt was made to administer these products on a regular basis. In patients who received trace metal supplementation, the decision to do so was made empirically prior to knowledge of serum or urinary levels. Serum Zinc and Copper Changes Changes in serum zinc and copper concentrations for the entire patient group are shown in Table 1 and in Figures 1 and 2. Although the initial mean level of serum zinc was within normal limits it was below the normal mean (92 + 2 ug/dl) in 12 of the 19 patients (Table 1). For the entire group over the course of parenteral feeding mean serum zinc concentration fell to levels significantly (p < 0.01) below those measured prior to TPN and below normal levels as well. Reduction of serum zinc concentration was noted in 13 of 19 patients while six exhibited either an increased or unchanged concentration. Two of these patients received blood products during their parenteral feeding course. During the course of TPN serum zinc concentrations were below the lower limits of the normal range in 17 patients, the levels having been within normal limits in
122
Ann. Surg. * January 1979
LOWRY AND OTHERS TABLE 1. Zinc, Copper and Nitrogen Metabolism During Total Parenteral Nutrition
Total Blood Products Given Patient (Sex-Age)
Clinical Status
1. RH(M-31) 2. MG(F-33) 3. TP(M-47) 4. BD(F-52) 5. JL(M-50)
P,S,II P,S,II II III S,II
MR(F-56) TW(M- 12) RB(F-63) CW(F-49) JP(M-56) ND(M-21) CM(F-62) LM(M-46) EJ(F-63) AS(F-17) HW(F-51) JB(M-61) 18. LK(M-55) 19. TZ(M-28) Mean + 1 SEM Normal (,ug/dl)
S,IV P,II I III IV P,IV P,III P,III P,III II P,II IV IV P,IV
6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17.
(ml)
Type
0 0 700 1220 1000 2045 0 0 0 0 560 1500 590 0 0 0 0 0 0 2000
RC RC WB RC
RC RL WB
WB
Serum Values
(Agldl)
Daily Urinary Excretion
(fig/day)
During TPN
Days Studied on TPN
Zn
Cu
Zn
Cu
5 6 16 26 20
80 100 140 65 100
72 126 182 134 76
85 85 85 65 75
50 74 82 62 78
45 45 105 60 55 130 76 35 30 55 32 60 40 85
32 58 54 44 144 62 76 94 114 102 60 82 62 122
22 36 7 27 21 8 11 8 18 29 8 28 42 16 19 ±+3
Pre-TPN
82 60 144 85 125 54 55 54 170 85 70 64 62 40 80 110 75 184 70 168 54 36 135 94 125 88 125 128 88 + 7 106 11 66 2 92 ± 2 106
+
6*t 76
+
7*t
Zn
Cu
1962 99 2780 253 266 18 3305 100 842 66 535 100 251 97 1360 77 4378 149 1742 490* 107 22* 333 23 36± 5
N1.
- Nur. (gms)
3.22 0.03 7.13 3.27 0.61 0.14 3.81 3.72 3.80 2.85 ± 0.75
* p < 0.01 with respect to control values. t p < 0.01 with respect to pretreatment values. Clinical status: P-Post-operative within two weeks of initiating TPN; S-Septic documented prior to initiating TPN; I-No detectable tumor present; II-Tumor burden estimated 5% of body weight. Blood products: RC-packed red blood cells; WB-fresh whole blood; PL-fresh plasma.
six of these patients prior to parenteral feeding (Fig. 1). In general, the longer the period of TPN administration, the greater the decrease in serum zinc concentration. However, a statistically significant decrease (p < 0.01)
lir-
was noted after two weeks of TPN by analysis of variance and after three weeks (p < 0.02) by paired t-test. Although the initial mean serum copper concentration for the entire patient group was not different from 140 V
in I
it. z
F
it. F
MV
NH
U3 HF~ i
W. 161
4SF
aSF 201-
0
0
4-10
il-l7
18-24
25-31 0
DAYS OF TPN
FIG. 1. Serum zinc concentrations before and during TPN. Ordinate, serum zinc concentration in ,ug/dl; abscissa, days after initiation of TPN. Normal serum zinc level is 92 2 ,ug/dl. X SEM (n = number of observations during indicated time period). ±
±
4-10
11-17
18-24
25.31
DAY OF TPN FIG. 2. Change in serum copper levels relative to pre-TPN values. Normal serum copper level is 106 + 2 ,ug/dl. X ± SEM (n = number of observations during indicated time period).
Vol. 189.9 NO. 125 100
.4 I
weeks while paired t-test revealed a significant (p < 0.02) decrease after three weeks of parenteral
o zinc *
feeding.
Is
75 F
soF
§
25 F
0
(n=9)
123
ZINC AND COPPER DURING TPN
I
(n=6) DAYS OF TPN
(n=9)
(n=9)
7
14
(n-3)
28
21
FIG. 3. Serial changes in serum zinc and copper levels for patients studied with concurrent urinary nitrogen balance and trace metal excretion. See Table 2 for urinary levels. X + SEM (n = number of patients studied at time indicated).
normal, 10 patients were observed to have serum copper concentrations below the normal mean (106 + 2 ug/dl) prior to undergoing TPN (Table 1). Ten patients exhibited a fall of serum copper concentration greater than 20 ug/dl during the course of TPN, four having been normal prior to the initiation of parenteral feeding. Only two patients exhibited an increase in serum copper concentration during their treatment and both of these patients received blood products during this period. As with serum zinc, in general, the longer the period of TPN administration, the greater the decrease in serum copper concentration. However, analysis of variance indicated a slight, but not statistically significant decrease in serum copper (0.10 < p > 0.05) after two
Considering the entire patient group, no correlation was observed between changes in serum zinc or copper concentration and administration of blood products. The mean daily oral consumption, in all cases less than one liter per day, also could not be correlated with changes in serum levels of these trace elements. Urinary Zinc, Copper, and Nitrogen Studies
Nine of the patients underwent concurrent evaluation of urinary zinc and copper excretion and nitrogen loss (Table 1). Fecal and fistulous losses were not analyzed, but in no case did the volume of fistula loss exceed 200 ml per day, and no patient with diarrhea was included. Based upon comparison of urinary nitrogen excretion and total nitrogen intake, all patients exhibited positive nitrogen retention. Weekly changes in serum zinc and copper for this latter group are shown in Figure 3. Although the downward trends in both zinc and copper concentrations were observed as in the data from the whole group, analysis of variance for changes in zinc (f = 1.05) or copper (f = 1.64) were not statistically significant at any period examined. These results may be related to the small number of patients comprising the study group.
Mean daily urinary excretion of zinc and copper in this group is shown for each week in Table 2. Excretion
TABLE 2. Urinary Excretion of Zinc, Copper and Nitrogen During Total Parenteral Nutrition
Entire Group Daily urinary metal excretion (,ug/24 hr): Zinc Copper Nitrogen balance*
(gm/24 hr) Postoperative Daily urinary metal excretion (,tgl24 hr): Zinc
Copper Nitrogen balance* (gm/24 hr) Non-operative Daily urinary metal excretion (,ug/24 hr): Zinc Copper Nitrogen balance* (gm/24 hr) * Total daily nitrogen intake
-
Week 1
Week 2
Week 3
Week 4
Week 5
(Days 1-7)
(Days 8-14)
(Days 15-21)
(Days 22-28)
(Days 29-35)
(9)
(9)
(6)
(3)
(2)
1792 ± 530 102 21
1903 ± 393 117 24
1607 ± 765 94 8
413 ± 114 56 15
4.05 ± 1.00
3.20 ± 0.83
4.15 ± 0.60
1.19 ± 3.20
(6)
(6)
(3)
1829 ± 476 108 + 31
2414 ± 839 128 + 34
2672 ± 1076 105 ± 3
2.83 ± 1.09
3.28 + 1.13
3.38 ± 1.58
(3)
(3)
(3)
(3)
1718 ± 1247 89± 22
882 + 402 93 25
894 ± 390 93 ± 25
413 ± 114 56 ± 15
6.49 ± 1.29
3.03 + 1.37
4.65 ± 0.15
4.72 ± 1.52
total daily urinary nitrogen excretion (n); x + SEM.
709 60 2.17
(2) 709 60
2.17
124
of both metals was above the normal range (333 + 23 ug/day for zinc, 36 + 5 ug/day for copper) following one to three weeks of TPN, but excretion decreased four and five weeks after continued TPN at a time when serum zinc and copper concentrations were consistently low. If these nine patients are evaluated with respect to recent operative status, an initially lower value of serum zinc is seen in the six recently operated patients (74 vs 110 ug/da). After three weeks of TPN, however, both groups had low serum zinc and copper concentrations. Six of these patients consistently excreted more than 1 ml of urinary zinc per day; five were in the postoperative period and one was undergoing abdominal irradiation for lymphoma. However, when the operative and non-operative groups were analyzed separately for urinary zinc excretion, no significant differences were noted. Urinary nitrogen balances likewise were not different between the two groups (Table 2). Mean daily oral intakes were not different between these groups, although the postoperative subjects consistently had a lower oral intake. Trace Metal Replacement Four additional patients, chosen for assumed susceptibility to acute trace metal deficiency because of weight loss and restricted oral intake prior to TPN, received a formulated trace metal solution (TMS) containing zinc (2.0 mg/ml), copper (0.4 mg/ml), manganese (0.2 mg/ml), and iodine (0.5 mg/ml). At the time of administration of this solution, values of serum zinc and copper were not known. 1801
120
_a. 100 100
FIG. 4. Response of individual patient levels of serum zinc to supplement intravenous zinc. X ± SEM.
u
z
D
cr
Ann. Surg. * January 1979
LOWRY AND OTHERS
80
Un
60 MEAN DAILY IV ZINC
40
o
0
a
1.57 mg/day
A
2.67 mg/day
4
8 12 DAYS OF TPN
160 140
120 7
z 100
FIG. 5. Response ofindividual patient levels of serum copper to supplement intravenous copper. X + SEM.
0
U, en
E 80
60 u6
MEAN DAILY IV COPPER
40
o 0.06
mg/day
e 0.07 mg/day
20
A 0.29 mg,day A 0.53 mg day
4
12 8 DAYS OF TPN
16
Serum responsiveness to this replacement is shown in Figures 4 and 5. Two patients exhibited a marked increase in serum zinc concentration whereas two patients exhibited a slight decline in serum levels. Serum copper concentration increased slightly in two patients, while it decreased in the other two. These changes could not be correlated with the amount of either zinc or copper added to the hyperalimentation solutions. Concurrent examination of urinary zinc and copper excretion was not changed from those reported for the entire group. No differences in urinary excretion of zinc and copper were noted on days these patients received trace metal supplementation compared to days when they did not receive the trace metal solution.
Analysis of Parenteral Nutrition Solutions Assay of zinc and copper from several parenteral nutrition solutions (n = 11) used in this study revealed that one liter contained 430 + 50 Ag of zinc (range 200-800 ,ug/L) and 23 Ag of copper (range 20-30 ,ug/L). Whereas minor variations occur among individual bottles, consistently small amounts of both zinc and copper were observed, regardless of supplementations with vitamin complexes. Discussion
0.29 mg/day
* 0.33 mg/day
20
180
16
While guidelines for maintenance of adequate zinc and copper nutrition are available for the general population39 there is, as yet, little information about zinc and copper requirements in patients undergoing parenteral feeding. Among several groups of patients
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ZINC AND COPPER DURING TPN
with moderate to severe malnutrition reductions in serum concentrations of zinc1' 12"9'28 and copper19'27'50 are being recognized more frequently both before and during any course of TPN. Prior to undergoing TPN, patients with various forms of malignancy have been reported to exhibit lower than normal levels of serum the association of this change with zinc, although 8th specific tumor types has not been clearly established.43 In our study, lower than normal levels of serum zinc were found prior to parenteral feeding in 12 of the 19 patients studied. It has also been suggested that many patients suffering from severe stress may be at risk of zinc deficiency.40 Acute decreases in serum zinc concentrations have been noted in adults subjected to a wide variety of stressful conditions16'30 and in children with protein calorie malnutrition.40 Markedly subnormal serum zinc concentration has been reported following major surgical procedures"' and in response to intravenous12'28 or oral34 refeeding. During TPN the patients in our study exhibited decreased serum levels of both zinc and copper and increased urinary excretion of both of these trace elements. While these findings have been previously observed by several groups of investigators with increasing frequency, the etiology for this reduction is unclear. Several suggestions have been put forward to explain these phenomena. Decreased blood zinc levels have been reported to occur following use of heat sterilized parenteral nutrition solutions presumably related to glucosamine complexes which can bind with zinc in serum and permit increased renal excretion.'3 This mechanism cannot apply in the present study because solutions were prepared without heat sterilization and filtered appropriately. Other investigators speculated that body zinc could be redistributed during TPN as acute and chronic tissue injury and repair occurs. 17 The details of this proposed etiology have not been reported. Decreased blood levels of both zinc and copper and increased urinary zinc and copper excretion has been reported in patients and normal volunteers given moderate to large amounts of L-histidine orally.21 These changes in blood and urine have also been associated with loss of total body zinc and copper. These changes were based upon in vitro studies in which amino acids, particularly histidine and cysteine, were shown to strip zinc21'38 from albumin, its major serum carrying protein. Similar changes were also observed for copper21 but to a lesser degree due to the relatively smaller amount of serum copper bound to albumin and therefore the smaller amount of copper available for transfer to amino acids. Since the principal form of urinary zinc and copper is that bound to amino acids, formation of histidyl and cystinyl zinc and copper complexes in blood is associated with increased
125
amounts of these species appearing in the urine.20 Indeed, this was the case, although histidine was not identified as the causitive agent, in previous studies during parenteral feeding.49 Further studies have suggested that the decreased serum zinc concentrations following TPN may be related to the infusion of L rather than to D forms of amino acids since infusion of D-L amino acids produced less zinc loss than infusion of L-amino acids alone.48 On the basis of the data collected, this hypothesis seems useful to describe the changes observed during TPN. In addition, interrelationships between blood albumin concentration and levels of blood amino acids are also important in determining blood and subsequently urinary zinc and copper levels. Any significant decrease in blood albumin concentration, which commonly occurs in patients with malignancy and with malnutrition, would also tend to magnify the decreased blood zinc and copper levels following intravenous histidine infusion and the increased urinary zinc and copper excretion. Changes in urinary zinc excretion during TPN may be reflective of several concurrent physiological and pathological conditions. Increased urinary zinc loss has been commonly observed following major surgical procedures with'5 and without28 TPN. However, studies during TPN have reported both elevated'5'28'49 and normal45 urinary zinc levels. In our studies after four weeks of TPN both urinary zinc and copper excretion decreased to levels not significantly different from normal. Thus, excretion of urinary zinc and copper must be related to the length of intravenous feeding as well as to the previous total body concentration of the trace metals. Relationships between blood and urinary concentrations of zinc and copper should also be based upon similar considerations. Findings of lowered blood zinc and elevated urinary zinc excretion have been previously noted in several disease states.22'28 Decreased urinary zinc excretion alone has been considered suggestive of zinc deficiency,36 particularly if the deficiency is profound and of long standing. Changes in blood zinc may or may not be reflected by changes in urinary zinc excretion depending again upon several physiological and pathological interrelationships. For example, excessive loss of zinc and copper in urine was not reflected in lowered levels of blood zinc or copper in
hyperparathyroidism.31 These complex interrelationships indicate that identification of zinc deficiency, per se, may not necessarily be a simple task. The symptoms associated with zinc deficiency may be either profound or vague. In acute zinc depletion anorexia, taste and smell dysfunction, cerebellar dysfunction, hyperparakeratosis of the skin and toxic psychosis have been observed.22 In more
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chronic zinc deficiency in children in the U.S., anorexia, taste loss and growth retardation have been observed20 and in adults, some manifestations of hypogonadism may also occur.36 However, marginal zinc deficiency has also been observed with few specific complaints.40 As noted above, blood and urine zinc levels provide only partial information about body zinc status. Hair zinc can provide information about chronic zinc depletion,46 while tests of taste acuity have also been useful in diagnosing zinc depletion, on both an acute and chronic basis.22'23 Decreased taste acuity was noted by us in a previous patient with proven zinc deficiency32 and Van Rij reported hypogeusia in a patient with well documented zinc deficiency following TPN.48 In this latter patient, administration of zinc completely reversed all the symptoms of the deficiency. Therapeutic methods for reversal of chronic or acute zinc deficiency have utilized 40-80 mg of intravenous or up to 220 mg of oral zinc sulphate.28 While these levels are far in excess of that required for normal daily balance, there does not appear to be significant toxicity to zinc unless given in massive (gram) doses.2'35 It is important to point out that the commonly held tenet that periodic infusions of fresh plasma or blood products will maintain adequate levels of body zinc appears unfounded in view of our present data. As yet, no study to support this widely held assumption has appeared. Based upon a previously formulated trace metal solution,42 replacement with as much as 1.6 mg of zinc given intravenously daily for 16 days was not adequate to increase blood zinc levels. Patients in whom limited oral intake is possible were similarly not maintained while consuming liquids presumably contaminated with zinc. Daily consumption of 500 to 700 ml of clear liquids in our study was accompanied by decreases in serum zinc levels. Serum copper concentrations are usually stable in individual patients and are observed to be below normal only in rare cases.27'29 Because copper deficiencies previously appeared to be unusual, some have recommended that replacement during TPN was unnecessary.25 As experience with total intravenous feeding has accumulated, however, cases of severe copper deficiency have been reported in children27 and adults.10'50 In addition, longitudinal studies during parenteral feeding have shown decreases in blood copper over the course of therapy.1'12'19 The results of this study also indicate a consistent decline in serum copper in patients undergoing TPN for one to five weeks. While it is not possible, based upon our data or those of others to identify the time course
Ann. Surg. * January 1979
over which the classical hematologic findings of copper deficiency appear, it would seem reasonable to assume that several weeks may be sufficient in previously malnourished patients. Defective absorption of iron in copper deficient animals may have relevance to the concurrent appearance of a microcytic, hypochromic anemia which may mask the true etiology.29 Improvement in anemia may be noted with iron administration, but depression of leukocyte counts is not affected.50 Measurement of ceruloplasmin levels may allow some prediction of potential for copper deficiency.12 Obviously patients undergoing aggressive chemotherapy are often anemic and neutropenic and interpretation of findings is therefore difficult. Levels of urinary copper excretion observed in these patients are two to four times the normal range.3'6 As with zinc, urinary copper is principally complexed with animo acids, and elevated urinary copper excretion observed in this study may reflect the stripping of blood copper from albumin with subsequent excretion in the urine.4'20 The nephrotic syndrome, Wilson's disease,5 acute liver disease,24 or Menkes steely hair disease14 have been associated with excessive urinary copper excretion. None of the patients reported here exhibited evidence of these pathological conditions. In the small group of patients who received a mean dose of 0.25 mg/day of parenteral copper replacement over 11 days, serum copper levels continued to fall by approximately 10 ug/dl. Previously suggested parenteral replacement levels have varied from 0.4 to 1.0 mg/ day. Studies are currently being conducted to determine the efficacy of such dosages in maintaining serum copper levels during intravenous feeding. It is apparent that concurrent blood product replacement is insufficient to maintain copper levels in these patients as would be expected from known levels in these fluids.'8 Excessive loss of zinc and copper is possible through fecal or intestinal fistula routes. While this mechanism has not been examined in our study, it would seem unlikely that this was a significant factor in our patients because intestinal losses were uniformly less than 200 ml per day. It should also be noted that during the period of study no patient reported here developed clinical symptoms that could be directly attributed to deficiency of either zinc or copper. Two patients exhibited serum zinc levels less than 40 ug/dl during TPN; one patient developed a plasma copper level below 40 ug/dl. While acute deficiency syndromes are now recognized for both elements, these clinical manifestations are variable and not necessarily correlated with blood metal
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ZINC AND COPPER DURING TPN
levels. The possibility that tissue stores may enable serum levels to be maintained at marginally low levels for sustained periods before the onset of acute deficiency symptoms is suggested from these and other
13.
data. 12,28,44
14.
Restricted intake associated with chronic loss of trace metals appears to be the most overt cause for reductions of zinc and copper concentrations during parenteral feeding. Levels of zinc and copper present in intravenous18'26 and parenteral nutrition12'44 solutions measured by others and ourselves are certainly insufficient to provide minimal requirements of these elements. It is also apparent that neither blood products nor limited oral intake are adequate to maintain zinc and copper concentrations in most patients. A trace element replacement regimen would appear to represent an important adjunct to the care of patients during parenteral nutrition.
15. 16. 17.
18. 19.
20. 21.
Acknowledgments The authors acknowledge the excellent technical assistance of Mrs. Catherine Gorschboth, Ms. Mary Patricia Howard, and Mr. Daniel C. Jones. Mr. Richard E. Davis, IV Additive Service, Clinical Center Pharmacy, and Mr. George E. Grimes, Pharmaceutical Development Service provided invaluable assistance with formulation of parenteral nutrition solutions.
23.
References
25.
1. Arakawa, T., Tamura, T., Igarashi, Y., et al.: Zinc Deficiency in Two Infants During Total Parenteral Alimentation for Diarrhea. Am. J. Clin. Nutr., 29:197, 1976. 2. Brocks, A., Reid, H. and Glazer, G.: Acute Intravenous Zinc Poisoning. Br. Med. J., 1:1390, 1977. 3. Butler, E. J. and Newman, G. E.: Urinary Excretion of Copper and its Concentrations in Blood of Normal Human Adults. J. Clin. Pathol., 9:157, 1956. 4. Cartwright, G. E., Gubler, C. J. and Wintrobe, M. M.: Studies on Copper Metabolism XI Copper and Iron Metabolism in Nephrotic Syndrome. J. Clin. Invest., 33:685, 1954. 5. Cartwright, G. E., Hodges, R. E., Gubler, C. J., et al.: Studies on Copper Metabolism XIII. Hepatolenticular Degeneration. J. Clin. Invest., 33:1487, 1954. 6. Cartwright, G. E. and Wintrobe, M. M.: Copper Metabolism in Normal Subjects. Am. J. Clin. Nutr., 14:224, 1964. 7. Clinical Methods for Atomic Absorption Spectroscopy, PerkinElmer Corp., Norwalk, Connecticut, 1971. 8. Davies, I. J. T., Musa, M. and Dormandy, T. L.: Measurements of Plasma Zinc II. In Malignant Disease. J. Clin. Pathol., 21:363, 1968. 9. Duke, J. H. and Dudrick, S. J.: Parenteral feeding. In Ballinger, W. F., Collins, J. A., Drucker, W. R., Dudrick, S. J., and Zeppa, R. (eds.) Manual of Surgical Nutrition. Philadelphia, Saunders, 1975. 10. Dunlap, W. M., James, G. W. and Hume, D. M.: Anemia and Neutropenia Caused by Copper Deficiency. Ann. Intern. Med., 80:470, 1974. 11. Fell, G. S., Cuthbertson, D. P., Morrison, C., et al.: Urinary Zinc Levels as an Indication of Muscle Catabolism. Lancet, 1:280, 1973. 12. Fleming, C. R., Hodges, R. E. and Hurley, L. S.: A Prospective
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37. Prasad, A. S., Schoomaker, E. B., Ortega, J., et al.: Role of zinc in man and its deficiency in sickle cell disease. pp. 603614; In Brewer, (ed.) Erythrocyte Structure and Function, G. J. New York Alan R. Liss, Inc., 1975. 38. Prasad, A. S. and Oberleas, D.: Binding of Zinc to Amino Acids and Serum Proteins in Vitro. J. Lab. Clin. Med., 76:416, 1970. 39. Recommended Dietary Allowances, Eighth Edition. Food and Nutrition Board, National Research Council, National Academy of Science, Washington, D.C., 1974. 40. Sandstead, H. H.: Zinc Nutrition in the United States. Am. J. Clin. Nutr., 26, 1251, 1973. 41. Sandstead, H. H., Shukry, A. S., Prasad, A. S., et al.: Kwashioknor in Egypt. I Clinical and Biochemical Studies with Special Reference to Plasma Zinc and Serum Lactic Dehydrogenase. Am. J. Clin. Nutr., 17:15, 1965. 42. Shils, M. E.: Guidelines for Total Parenteral Nutrition. JAMA, 220:1721, 1972. 43. Smith, J. C., Jr., Hansen, H. H., Howard, M. P., et al.: Plasma Zinc Concentration in Patients with Bronchogenic Cancer. Lancet, 2:1323, 1971. 44. Solomons, N. W., Layden, T. J., Rosenberg, I. H., et al.: Plasma Trace Metals During Total Parenteral Nutrition. Gastroenterology, 70:1022, 1976.
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45. Solomons, N., Vo-Khactu, K., Layden, T., et al.: Plasma Trace Metal Dynamics During Total Parenteral Alimentation. Am. J. Clin. Nutr., 28:421, (abstr.) 1975. 46. Strain, W. H., Steadman, C. T., Lankau, C. A., Jr., et al.: Analysis of Zinc Levels in Hair for the Diagnosis of Zinc Deficiency in Man. J. Lab. Clin. Med., 68:244, 1966. 47. Vallee, B. L., Wacker, W. E. C., Bartholomay, A. F. and Hoch, F. L.: Zinc Metabolism in Hepatic Dysfunction. Ann. Intern. Med., 50:1077, 1959. 48. Van Rij, A. M. and McKenzie, J. M.: Hyperzincuria and zinc deficiency. In Kuichgemer, M. (ed.) Total Parenteral Nutrition. T.E.M.A. III, (in press, 1977). 49. Van Rij, A. M., McKenzie, J. M. and Dunckley, J. V.: Excessive Urinary Zinc Losses and Amino Aciduria During Intravenous Alimentation. Proc. Univ. Otago Med. Sch., 53:77, 1975. 50. Vilter, R. W., Bozian, R. C., Hess, E. V., et al.: Manifestations of Copper Deficiency in a Patient with Systemic Sclerosis on Intravenous Hyperalimentation. N. Engl. J. Med., 291:188, 1974. 51. Winer, B. J.: Statistical Principles in Experimental Design. New York, McGraw-Hill Company, 1962. 52. Wretlind, A.: Complete Intravenous Nutrition: Theoretical and Experimental Background. Nutr. Metab., 14 (suppl.), p. 51, 1972.
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