595 7.
Braga M, Baccari P, Scaccabarozzi S, et al: Prognostic role of preoperative nutritional and immunological assessment in the surgical patient. JPEN 12:138-142, 1988
More on Risk Factors for Central Venous Catheter-Related Vascular Erosions
Estimating Energy Expenditure
To the Editor: We read with great interest the review article by Mukau and colleagues that described risk factors for central To the Editor: Williams and Fuenning (JPEN 15:509, 1991)1 stated venous catheter (CVC)-related vascular erosion. We that circulatory indirect calorimetry (CIC) is an accept- are in full agreement with the authors that the use of able alternative to estimate energy expenditure in the both a left-sided approach and large diameter, straightcritically ill patient instead of measuring it from Vo2 and tipped catheters are risk factors. We would like to offer VC02 of respiratory gases (RIC). However, according to some additional observations. A left-sided approach presents a risk because it predisBland and Altman2 it seems inadequate to calculate the correlation coefficient to assess the degree of agreement poses the patient to an unacceptable incident angle of between two methods. We believe the authors would the CVC tip to the superior vena cava (SVC). It is the have improved the analysis of their data if they had tip of the CVC that causes erosion, especially when the reported the mean difference (bias) and the standard CVC is constructed of a relatively inflexible material and the tip is tapered. deviation of the differences (precision). An in vitro study we published recently showed that We have recalculated both values from their data catheter material, angle of incidence of catheter tip to in 1 a bias and of 313 ± plotted Figure finding precision 352 kcal/day RIC with respect to CIC. Both values vessel wall, and number of lumens are factors that influpermit the calculation of the agreement between both ence the relative perforation potential of a CVC.’ In this methods (mean ± 2 SD) as 1015 to -393 kcal/day, which study, the CVCs with less perforation potential included shows a considerable discrepancy. The discrepancy was those with single lumens, those with pigtail tip design, those made of softer (silicone) materials, those positioned so great that 10 of 22 (45%) RIC values were at least 20% greater than CIC values. We have also reanalyzed at incident angles of 50° or less, and particularly those the data of the study of Ligget et al3 and a mean differ- positioned at incident angles of 40° or less. A retrospective review of the literature between 1966 and 1991 ence between RIC and CIC methods of -35.7 ± 137 kcal/ showed that in cases where great vein perforations ocwas which is more there day found, acceptable, although curred and the published chest radiographs allowed the were still 8 of 20 (40%) patients showing RIC values at incident angle between catheter tip and SVC to be deleast 10% greater or lower than CIC values. 38), the incident angle between catheter It would be interesting to know how well compared termined (n tip and perforated vessel wall was always greater than both methods in patients breathing FI02 0.5. Another fact that could explain the lack of agreement 40°.3 In two of the four patients with SVC perforation between RIC and CIC methods in Williams and Fuen- reported by Mukau and colleagues, the CVC incident ning’s paper could be that RIC values were obtained 20 angles that could be measured were 55° and 75’. With the data now available, these represent unacceptable to 40 minutes after CIC measurements and not simultaincident angles for a CVC. We concur completely with neously. There is no relation between reference 7 and the the recommendations of Mukau and colleagues and statement of the third paragraph of the introduction. would like to make the following additional suggestions to help decrease the incidence of delayed perforation by The correct reference was probably number 8. a CVC. J. IBÁÑEZ (1) Position CVCs to maintain an incident angle between catheter tip and SVC of 40° or less. (2) Use CVCs J. M. RAURICH with flexible and/or nontapered tips (eg, pigtail CVCs). Intensive Care Unit (3) Avoid using multilumen CVCs when a single-lumen Hospital Son Dureta Palma de Mallorca, Spain CVC would be clinically appropriate. =
ROBERT H. BLACKSHEAR, MD NIKOLAUS GRAVENSTEIN, MD
Departments of Anesthesiology and Neurosurgery University of Florida College of Medicine
REFERENCES
RR, Fuenning CR: Circulatory indirect calorimetry in the critically ill. JPEN 15:509, 1991 Bland JM, Altman DG: Statistical methods for assessing agreement
1. Williams
2.
between 3.
two
methods. Lancet i:307, 1986
REFERENCES
Ligget SB, St John RE, Lefrak SS: Determination of resting energy expenditure utilizing the thermodilution pulmonary artery catheter. Chest
Gainesville, Florida
91:562, 1987
-
-
-
1. Makau venous
-
~
..
--.
-.
--
-
-.,
-
L, Talamini MA, Sitzmann JV: Risk factors for central catheter-related vascular erosions. JPEN 15:513-516, 1991
Downloaded from pen.sagepub.com at UNIV ARIZONA LIBRARY on June 4, 2015
Braga M, Baccari P, Scaccabarozzi S, et al: Prognostic role of preoperative nutritional and immunological assessment in the surgical patient. JPEN 12:138-142, 1988
More on Risk Factors for Central Venous Catheter-Related Vascular Erosions
Estimating Energy Expenditure
To the Editor: We read with great interest the review article by Mukau and colleagues that described risk factors for central To the Editor: Williams and Fuenning (JPEN 15:509, 1991)1 stated venous catheter (CVC)-related vascular erosion. We that circulatory indirect calorimetry (CIC) is an accept- are in full agreement with the authors that the use of able alternative to estimate energy expenditure in the both a left-sided approach and large diameter, straightcritically ill patient instead of measuring it from Vo2 and tipped catheters are risk factors. We would like to offer VC02 of respiratory gases (RIC). However, according to some additional observations. A left-sided approach presents a risk because it predisBland and Altman2 it seems inadequate to calculate the correlation coefficient to assess the degree of agreement poses the patient to an unacceptable incident angle of between two methods. We believe the authors would the CVC tip to the superior vena cava (SVC). It is the have improved the analysis of their data if they had tip of the CVC that causes erosion, especially when the reported the mean difference (bias) and the standard CVC is constructed of a relatively inflexible material and the tip is tapered. deviation of the differences (precision). An in vitro study we published recently showed that We have recalculated both values from their data catheter material, angle of incidence of catheter tip to in 1 a bias and of 313 ± plotted Figure finding precision 352 kcal/day RIC with respect to CIC. Both values vessel wall, and number of lumens are factors that influpermit the calculation of the agreement between both ence the relative perforation potential of a CVC.’ In this methods (mean ± 2 SD) as 1015 to -393 kcal/day, which study, the CVCs with less perforation potential included shows a considerable discrepancy. The discrepancy was those with single lumens, those with pigtail tip design, those made of softer (silicone) materials, those positioned so great that 10 of 22 (45%) RIC values were at least 20% greater than CIC values. We have also reanalyzed at incident angles of 50° or less, and particularly those the data of the study of Ligget et al3 and a mean differ- positioned at incident angles of 40° or less. A retrospective review of the literature between 1966 and 1991 ence between RIC and CIC methods of -35.7 ± 137 kcal/ showed that in cases where great vein perforations ocwas which is more there day found, acceptable, although curred and the published chest radiographs allowed the were still 8 of 20 (40%) patients showing RIC values at incident angle between catheter tip and SVC to be deleast 10% greater or lower than CIC values. 38), the incident angle between catheter It would be interesting to know how well compared termined (n tip and perforated vessel wall was always greater than both methods in patients breathing FI02 0.5. Another fact that could explain the lack of agreement 40°.3 In two of the four patients with SVC perforation between RIC and CIC methods in Williams and Fuen- reported by Mukau and colleagues, the CVC incident ning’s paper could be that RIC values were obtained 20 angles that could be measured were 55° and 75’. With the data now available, these represent unacceptable to 40 minutes after CIC measurements and not simultaincident angles for a CVC. We concur completely with neously. There is no relation between reference 7 and the the recommendations of Mukau and colleagues and statement of the third paragraph of the introduction. would like to make the following additional suggestions to help decrease the incidence of delayed perforation by The correct reference was probably number 8. a CVC. J. IBÁÑEZ (1) Position CVCs to maintain an incident angle between catheter tip and SVC of 40° or less. (2) Use CVCs J. M. RAURICH with flexible and/or nontapered tips (eg, pigtail CVCs). Intensive Care Unit (3) Avoid using multilumen CVCs when a single-lumen Hospital Son Dureta Palma de Mallorca, Spain CVC would be clinically appropriate. =
ROBERT H. BLACKSHEAR, MD NIKOLAUS GRAVENSTEIN, MD
Departments of Anesthesiology and Neurosurgery University of Florida College of Medicine
REFERENCES
RR, Fuenning CR: Circulatory indirect calorimetry in the critically ill. JPEN 15:509, 1991 Bland JM, Altman DG: Statistical methods for assessing agreement
1. Williams
2.
between 3.
two
methods. Lancet i:307, 1986
REFERENCES
Ligget SB, St John RE, Lefrak SS: Determination of resting energy expenditure utilizing the thermodilution pulmonary artery catheter. Chest
Gainesville, Florida
91:562, 1987
-
-
-
1. Makau venous
-
~
..
--.
-.
--
-
-.,
-
L, Talamini MA, Sitzmann JV: Risk factors for central catheter-related vascular erosions. JPEN 15:513-516, 1991
Downloaded from pen.sagepub.com at UNIV ARIZONA LIBRARY on June 4, 2015
