Improved Diaphragmatic Function after Surgical Plication for Unilateral Diaphragmatic Paralysis 1- 3
DAVID E. CICCOLELLA, BENEDICT D. T. DALY, and BARTOLOME R. CELLI
Introduction Unilateral diaphragmatic paralysis has been associated with alterations in respiratory mechanics (1, 2) and respiratory muscle function (3, 4). Plication of the diaphragm in unilateral diaphragmatic paralysis in adults (5, 6) and bilateral diaphragmatic paralysis in children (7-12) improves lung volumes and respiratory mechanics. Little is known about the mechanisms by which this occurs and the effect of this procedure on diaphragmatic and respiratory muscle function: In this study, we prospectivelyexaminedthe effect of diaphragmatic plication on respiratory mechanics, arterial blood gas measurements, and respiratory muscle function in a symptomatic patient with left hemidiaphragmatic paralysis. Case Report A 37-yr-old army sergeant with a history of chest and abdominal trauma resulting from parachute jumping presented to our pulmonary clinic with complaints of dyspnea on exertion and the inability to meet the physical requirements of his job. On physical examination the patient had decreased breath sounds on the left hemithorax with minimal diaphragmatic movement. A neurologic evaluation, including electromyographic studies, ruled out a generalized neuromuscular disease as a cause of his elevated diaphragm. On presentation, and as early as 1988, his chest roentgenogram showed an elevated left hemidiaphragm (figure 1). Prior roentgenograms at other hospitals had been interpreted as normal. Thoracic computerized tomograms and magnetic resonance imaging showed an elevated left hemidiaphragm consistent with either diaphragmatic rupture or paralysis. .Complete blood count, liver function tests, electrolyte studies, and thyroid function tests were normal. All physiologic measurements were made with the patient in the sitting position. Pulmonary function studies (FVC, FEV 1, FEVl/FVC, maximal voluntary ventilation [MVV], and plethysmographic lung volumes) were performed using standard techniques (13). Arterial blood gas determinations were obtained while breathing room air. Gastric (Pg) and esophageal (Ppl) pressures were measured using two thin-walled balloons positioned in the stomach and in the middle third of the esophagus, respectively. Transdiaphragmatic pressure{Pdi) was determined as the difference between Pg and Ppl. Maximal transdiaphragmatic pressure (Pdi max) , was measured while the patient performed a maximal inspiratory effort at FRC with a partially closed shutter placed at the mouth. Continuous recording of Pg and Ppl were evaluated. Pg-Ppl plots were constructed by averaging the end-inspiratory Ppl (PpII) and Pg (PgI) and end-expiratory Ppl (PpIE) and Pg (PgE) for five consecutive tidal breaths. The beginning and end of inspiration was defined from the points of zero flow. The slope of the Pg-Ppl
SUMMARY We studied pulmonary function tests, maximal voluntary ventilation, arterial blood gases, and respiratory muscle strength and recruitment pattern In a 37-yr-old symptomatic man before and after surgical plication for a left unilateral diaphragmatic paralysis. After plication, FVC, FEV1 , TLC and FRC Increased, whereas residual volume remained unchanged. Arterial P0 2 improved from 70 to 87 mm Hg. Diaphragmatic strength, as expressed by the maximal transdlaphragmatlc pressure Increased from 30 to 75 em H 20 , and maximal voluntary ventilation Increased from 74 to 123 L/mln. Ventilatory muscle recruitment also changed: there was a shift from a positive to a negative APglAPpl slope during tidal breathing. This indicates more effective diaphragmatic recruitment after the procedure. We conclude that surgical plication may be of benefit to patients with symptomatic unilateral diaphragmatic paralysis. The improvement Is due to improved respiratory muscle function. AM REV RESPIR DIS 1992; 146:797-799
plot (~Pg/~Ppl) was calculated using the following equations: ~Pg/~Ppl = (PgI - PgE)/(PplI PpIE). In this analysis, the more negative the value for ~Pg/~Ppl, the greater the contribution of the diaphragm/abdomen to the generation of ventilatory pressures (4). The patient underwent exploratory thoracotomy on April 4, 1990. Intraoperative phrenic nerve stimulation confirmed the diagnosis of left hemidiaphragm paralysis. The hemidiaphragm was plicated by folding the lateral and posterior portion of the leaflet on itself and gathering the muscle within the pleats, which were oriented semicircumferentially. In addition, pledgets were used to secure the stitches, which were placed in a horizontal mattress-type fashion. Tension was taken off the line of plication, and the sutures were secured into position. Excursion of the left hemidiaphragm was significantly reduced. A biopsy of the lingula was also performed, and the lung was normal. The patient had an uneventful recovery. Subsequently, he
had chest roentgenograms, a pulmonary function test, and ventilatory muscle and arterial blood gas studies. The chest roentgenogram (figure 2) approx-
(Received in original form October 23, 1991 and in revised form March 9, 1992) 1 From the Pulmonary Section and Cardiothoracic Surgical Section, Department of Veterans Affairs Medical Center, Pulmonary Center, Boston University School of Medicine, Department of Surgery, Thfts University School of Medicine, Boston, Massachusetts. 2 Supported by the Veterans Administration Research Service. 3 Correspondence and requests for reprints should be addressed to Bartolome R. Celli, M.D., Chief, Pulmonary Section, Department of Veterans Affairs Medical Center, 150 South Huntington Avenue, Boston, MA 02130.
Fig. 1. Posteroanterior chest roentgenogram obtained before surgical plication. The left hemidiaphragm is elevated because of unilateral paralysis.
797
798
CASE REPORT
TABLE 2 EFFECTS OF PLICATION ON DIAPHRAGMATIC STRENGTH AND MAXIMAL VOLUNTARY VENTILATION IN A PATIENT WITH UNILATERAL DIAPHRAGMATIC PARALYSIS After Plication
6/89 Pdi max, cm H2O Pplmax, cm H2O Pg max, cm H2O MVV, Llmin
30
-34 -4 74
6/90 59 -57 +2
10/90
3/91
51 -48 +3
75
-77 -2
188
123
Definition of abbreviations: Pdimax =
maximal transdiaphragmatic pressure; Pplmax = maximal inspiratory pleural pressure; Pgmax = maximalinspiratory gastricpressure; MVV = maximal voluntary ventilation.
Fig. 2. Posteroanterior chest roentgenogram obtained after surgical plication. Notice the return of the left hemidiaphragm to a more normal position.
imately 1 yr after plication shows the left hemidiaphragm in a near normal position. Results of pulmonary function studies, DLcO, and arterial blood gas measurements are presented in table 1. At baseline, the patient demonstrated a restrictive pattern, with low FVC, FEV 1, but normal FEV1/FVC. After plication, the FVC and FEV 1improved rapidly over the next 2 months. At 20 months it had reached 88070 of predicted. Although in the low normal predicted range prior to plication, TLC and FRC also improved but residual volume remained unchanged. Along with an improvement in lung volumes, the DLCO increased from a baseline of 17.6 to 25.5 mllmin/mm Hg (81% of predicted). Arterial Po 2 also improved, from 70 to 87 mm Hg, 20 months after surgery. The ventilatory muscle studies are summarized in table 2. Diaphragmatic strength as expressed by
the Pdi max increased from 30 to 59 cm H 20 at 2 months, and to 75 cm H 20 at 20 months. MVV also improved, from a baseline of 74 L/min (50% of predicted) to 118 L/min at 2 months and to 123 L/min (78% predicted) at 20 months postplication. It can be seen in figure 3 that the ventilatory muscle recruitment pattern also changed; ~/PgI~Ppl changed from an abnormal positive to a more normal negative value, consistent with more effective inspiratory diaphragmatic recruitment during tidal breathing, falling within the normal range as described by others (3, 4).
Discussion This study showed that surgical plication of the left hemidiaphragm in a patient with symptomatic unilateral diaphragmatic paral-
TABLE 1
ysisresults in clinical and physiologicimprovement. Vital capacity, lung volumes and Pa02 increased progressively after surgery. This was associated with an increase in diaphragmatic strength and MVV. There was a change in ventilatory muscle recruitment to more effective diaphragmatic recruitment during inspiration. Patients with unilateral diaphragmatic paralysis have been shown to have low VC, FEV 1 and FVC (1-11). The patient in this report manifested similar reductions in FVC and FEV 1, the values of which remained decreased until the time of surgery. Although in our patient, reductions in TLC and FRC were not demonstrated by comparison to the predicted normal values, reductions in TLC and FRC have been reported in patients prior to plication (5,6). In these reports, plication resulted in an increase in TLC, FRC, and spirometric lung volumes, whereas residual volume, as in our patient, remained unchanged (5, 6). The improvement in lung volumes has been shown to persist for as long as 10yr after surgery (6). Arterial Po2has been reported to be reduced in unilateral diaphragmatic paralysis (3, 6), and it improves after plication. In our patient, Pa02 also improved (table 1). The improvement in gas exchange is most likely due to the change in the configuration and function of the diaphragm, resulting in less atelecta-
EFFECT OF SURGICAL PLICATION ON SPIROMETRIC VALUES, LUNG VOLUMES, AND BLOOD GAS DETERMINATION IN A PATIENT WITH UNILATERAL DIAPHRAGMATIC PARALYSIS· Before Plication
10/88 FVC, L FEV 1 , L FEV 1/FVC TLC, L IC, L FRC, L RV, L ERV, L OLeo, mllmin/mm Hg pH Pao2, mm Hg Paeo2, mm Hg
3.59 (60) 2.69 (59) 0.74
4/89 3.34 (56) 2.43 (54) 0.73
7.46 70 35
13
After Plication
4/90
5/90
3.52 (59) 2.63 (59) 0.75 6.64 (80) 2.30 (62) 4.34 (94) 3.44 (144) 0.90 (40) 17.6 (54)
4.17 (70) 3.24 (73) 0.78 6.89 (83) 2.70 (73) 4.19 (91) 2.89 (121) 1.30 (58) 23.4 (73)
6/90 4.82 (81) 3.55 (80) 0.74
7.45 79 32
3/91 5.22 (88) 3.73 (85) 0.71 8.4 (101) 3.3 (90) 5.1 (110) 3.2 (135) 1.9 (85) 25.5 (80) 7.41 87 38
Definition of abbreviations: Ie = inspiratory capacity;RV = residual volume; ERV = expiratory reserve volume; OLeo = single· breath eo diffusingcapacity. • Values in parentheses indicatepercent predicted.
E
a
N J:
1
10
o e,
'"
.~o o •
7+-------+-------+---12
-2
Fig. 3. Plots of gastric versus pleural pressure changes during tidal breathing before (open circles) and after (closedcircles)plication for unilateral diaphragmatic paralysis. I = end of inspiration; E = end of expiration. The change in slope from a positive to a negative value indicates more effective diaphragmatic recruitment during tidal breathing .
799
CASE REPORT
sis, increased lung volume, and improved ventilation/perfusion ratios. Although not specifically commented upon, DLco in one study showed a slight reduction (85070 of predicted), which improved after plication (6). In our patient, DLCO also improved to a similar degree, but the baseline value was lower than the value reported in that study (14). The mechanisms for the improved respiratory mechanics after diaphragmatic plication, for both unilateral and bilateral diaphragmatic paralysis, have been given little attention. Proposed hypotheses for the improved respiratory mechanics include: (1) a change in the configuration of the diaphragm, (2) increased ability of the diaphragm to act as a pressure generator, or (3) a combination of both. Schoenfeld and coworkers (7) measured Pdi in a 2-yr-old girl with idiopathic peripheral neuropathy and bilateral diaphragmatic paralysis, and they found no increase after plication (7). Because lung volume (as measured by chest roentgenogram) increased after the procedure, these investigators suggested that the improved respiratory function resulted only from a change in diaphragmatic configuration. Takeda and coworkers (15) studied dogs with bilaterally induced diaphragmatic paralysis and showed an increase in tidal volume but no increase in Pdi max after plication. These findings are consistent with the observation of increased lung volume without a change in diaphragmatic pressure generation, as in the patient described earlier (7). Because the respiratory muscle physiology in bilateral diaphragmatic paralysis is different from that in unilateral diaphragmatic paralysis (3, 4), we reasoned that plication of the affected side would improve the ability of the hemidiaphragm to act as a pressure generator. Another study by Thkedaand coworkers(16) supported our contention. These investigators studied dogs with unilaterally induced diaphragmatic paralysis, and they showed a significant increase in Pdi max after plication. The baseline value of Pdi max in our patient was similar to those reported in the literature (3, 4). The large increase after plication brought the value close to but not within the normal range seen in our laboratory (range, 110to 250 em H 2 0 ). Although the case we report is the first one in which a patient has undergone systematical evaluation of respiratory muscle function, wediscovereda study that contained one patient evaluated before and after plication for a flaccid right hemidiaphragm (4). Although the patient was not discussed in terms of the effect of the plica-
tion, the investigators did show an increase in Pdi max , from 33 to 53 em H 2 0 , similar to the results in our patient. The mechanism for the increased Pdi max after plication for unilateral paralysis might be explained as follows: In the paralyzed state, as the right hemidiaphragm descends during inspiration, the gastric pressure would not be expectedto increase normally because the flaccid left diaphragm develops paradoxical motion, resulting in a decreased volume of air to the left lung. After plication, the left hemidiaphragm is less compliant. As the right hemidiaphragm descends during inspiration, Pg increases, with a resulting smaller decrease in volume of the left lung. It is also possible that the stabilized left hemidiaphragm better opposed the expanding action of other inspiratory muscles of the rib cage. Not only was the strength of the diaphragm increased but there was also an improvement in overall respiratory muscle function. MVV increased from 79 to 123 L/min, representing a 55% increase. The best explanation for the increase in MVV is the increase in force reserve. It is known that the factors that determine diaphragmatic fatigability are the ratio of pressure developed over maximal pressure (PdilPdimax) times the duration of inspiration as a function of total respiratory time (n/Ttot). The increase in Pdi max , when all the other factors remained equal, must have resulted in a drop in tension time index and hence in fatigability. Finally, plication also resulted in changes in the pattern of ventilatory muscle recruitment. Unilateral diaphragmatic paralysis is characterized by increased use of intercostal and accessory inspiratory muscles (3, 4, 18, 19). On the basis of the results of the ventilatory muscle studies during tidal breathing in our patient, paradoxical diaphragmatic motion was demonstrated before plication. This is best shown in figure 1where the dPg/dPpl plots reveal a positive slope. Plication resulted in normalization of the slope, which now became negative as seen in normal subjects (3, 4). The capacity to better recruit the diaphragm helps explain the improved mechanics and blood gases as more ventilation reached the bases. In summary, we have shown that plication of the affected hemidiaphragm in unilateral paralysis results in symptomatic clinical and physiologic improvement. The improvement in pulmonary function, gas exchange, and respiratory muscle function is best explained by the increased strength and endurance of
the plicated diaphragm. These results support the use of surgical plication for patients with symptomatic unilateral diaphragm paralysis.
References 1. Piehler JM, Pairolero PC, Gracey DR, Bernatz PE. Unexplained diaphragmatic paralysis. J Thorac
Cardiovasc Surg 1982; 84:861-4. 2. Easton PA, Fleetham JA, de la Rocha A, Anthonisen NR. Respiratory function after paralysis of the right hemidiaphragm. Am Rev Respir Dis 1983; 127:125-8. 3. Lisboa C, Pare PO, Pertuze J, et al. Inspiratory muscle function in unilateral diaphragmatic paralysis. Am Rev Respir Dis 1986; 134:488-92. 4. Hillman DR, Finucane KE. Respiratory pressure partitioning during quiet inspiration in unilateral and bilateral diaphragmatic weakness. Am Rev Respir Dis 1988; 137:1401-5. 5. Wright CD, Williams JG, Ogilvie CM, Donnelly RJ. Results of diaphragmatic plication for unilateral diaphragmatic paralysis.J Thorac Cardiovase Surg 1985; 90:195-8. 6. Graham DR, Kaplan 0, Evans CC, Hind CRK, Donnelly RJ. Diaphragmatic plication for unilateral diaphragmatic paralysis: a 10year experience. Ann Thorac Surg 1990; 49:248-52. 7. Schoenfeld T, O'Neal MH, Platzker ACG, et al. Function of the diaphragm before and after plication. Thorax 1980; 35:631-2. 8. Marcos 11, Grover FL, Trinkle JK. Paralyzed diaphragm. Effect of plication on respiratory mechanics. J Surg Res 1974; 16:523-6. 9. Haller JA Jr, Pickard LR, Tepas 11, et al. Management of diaphragmatic paralysis in infants with special emphasis on selection of patients for operative plication. J Pediatr Surg 1979; 14:779-85. 10. Swartz MJ, Filler RM. Plication of the diaphragm for symptomatic phrenic nerve paralysis. J Pediatr Surg 1978; 13:259-63. 11. Stone KS,Brown JW, Canal OF, KingH. Longterm fate of the diaphragm surgically plicated during infancy and early childhood. Ann Thorac Surg 1987; 44:62-5. 12. Ribet M. Diaphragmatic plication. Ann Thorac Surg 1990; 50:855-6. 13. American Thoracic Society. Snowbird workshop on standardization of spirometry. ATS statement. Am Rev Respir Dis 1979; 119:831-8. 14. Arborelius M Jr, Lilja B, Senyk J. Regional and total lung function studies in patients with hemidiaphragmatic paralysis. Respiration 1975; 32:253-64. 15. Takeda S, Nakahara K, Fujii Y, et al. Effects of diaphragm plication on respiratory mechanics and diaphragm function (abstract). Am Rev Respir Dis 1991; 143:A365. 16. Takeda S, Nakahara K, Fujii Y, Miyoshi S, Matsuda H. Effect of diaphragmatic plication on respiratory mechanics in uni- and bilateral diaphragmatic paralyses in dogs. Chest 1991; loo:14S. 17. Bellemare F, Grassino A. Effect of pressure and timing of contraction on human diaphragmatic fatigue. J Appl Physiol 1982;53:1190-5.
DAVID E. CICCOLELLA, BENEDICT D. T. DALY, and BARTOLOME R. CELLI
Introduction Unilateral diaphragmatic paralysis has been associated with alterations in respiratory mechanics (1, 2) and respiratory muscle function (3, 4). Plication of the diaphragm in unilateral diaphragmatic paralysis in adults (5, 6) and bilateral diaphragmatic paralysis in children (7-12) improves lung volumes and respiratory mechanics. Little is known about the mechanisms by which this occurs and the effect of this procedure on diaphragmatic and respiratory muscle function: In this study, we prospectivelyexaminedthe effect of diaphragmatic plication on respiratory mechanics, arterial blood gas measurements, and respiratory muscle function in a symptomatic patient with left hemidiaphragmatic paralysis. Case Report A 37-yr-old army sergeant with a history of chest and abdominal trauma resulting from parachute jumping presented to our pulmonary clinic with complaints of dyspnea on exertion and the inability to meet the physical requirements of his job. On physical examination the patient had decreased breath sounds on the left hemithorax with minimal diaphragmatic movement. A neurologic evaluation, including electromyographic studies, ruled out a generalized neuromuscular disease as a cause of his elevated diaphragm. On presentation, and as early as 1988, his chest roentgenogram showed an elevated left hemidiaphragm (figure 1). Prior roentgenograms at other hospitals had been interpreted as normal. Thoracic computerized tomograms and magnetic resonance imaging showed an elevated left hemidiaphragm consistent with either diaphragmatic rupture or paralysis. .Complete blood count, liver function tests, electrolyte studies, and thyroid function tests were normal. All physiologic measurements were made with the patient in the sitting position. Pulmonary function studies (FVC, FEV 1, FEVl/FVC, maximal voluntary ventilation [MVV], and plethysmographic lung volumes) were performed using standard techniques (13). Arterial blood gas determinations were obtained while breathing room air. Gastric (Pg) and esophageal (Ppl) pressures were measured using two thin-walled balloons positioned in the stomach and in the middle third of the esophagus, respectively. Transdiaphragmatic pressure{Pdi) was determined as the difference between Pg and Ppl. Maximal transdiaphragmatic pressure (Pdi max) , was measured while the patient performed a maximal inspiratory effort at FRC with a partially closed shutter placed at the mouth. Continuous recording of Pg and Ppl were evaluated. Pg-Ppl plots were constructed by averaging the end-inspiratory Ppl (PpII) and Pg (PgI) and end-expiratory Ppl (PpIE) and Pg (PgE) for five consecutive tidal breaths. The beginning and end of inspiration was defined from the points of zero flow. The slope of the Pg-Ppl
SUMMARY We studied pulmonary function tests, maximal voluntary ventilation, arterial blood gases, and respiratory muscle strength and recruitment pattern In a 37-yr-old symptomatic man before and after surgical plication for a left unilateral diaphragmatic paralysis. After plication, FVC, FEV1 , TLC and FRC Increased, whereas residual volume remained unchanged. Arterial P0 2 improved from 70 to 87 mm Hg. Diaphragmatic strength, as expressed by the maximal transdlaphragmatlc pressure Increased from 30 to 75 em H 20 , and maximal voluntary ventilation Increased from 74 to 123 L/mln. Ventilatory muscle recruitment also changed: there was a shift from a positive to a negative APglAPpl slope during tidal breathing. This indicates more effective diaphragmatic recruitment after the procedure. We conclude that surgical plication may be of benefit to patients with symptomatic unilateral diaphragmatic paralysis. The improvement Is due to improved respiratory muscle function. AM REV RESPIR DIS 1992; 146:797-799
plot (~Pg/~Ppl) was calculated using the following equations: ~Pg/~Ppl = (PgI - PgE)/(PplI PpIE). In this analysis, the more negative the value for ~Pg/~Ppl, the greater the contribution of the diaphragm/abdomen to the generation of ventilatory pressures (4). The patient underwent exploratory thoracotomy on April 4, 1990. Intraoperative phrenic nerve stimulation confirmed the diagnosis of left hemidiaphragm paralysis. The hemidiaphragm was plicated by folding the lateral and posterior portion of the leaflet on itself and gathering the muscle within the pleats, which were oriented semicircumferentially. In addition, pledgets were used to secure the stitches, which were placed in a horizontal mattress-type fashion. Tension was taken off the line of plication, and the sutures were secured into position. Excursion of the left hemidiaphragm was significantly reduced. A biopsy of the lingula was also performed, and the lung was normal. The patient had an uneventful recovery. Subsequently, he
had chest roentgenograms, a pulmonary function test, and ventilatory muscle and arterial blood gas studies. The chest roentgenogram (figure 2) approx-
(Received in original form October 23, 1991 and in revised form March 9, 1992) 1 From the Pulmonary Section and Cardiothoracic Surgical Section, Department of Veterans Affairs Medical Center, Pulmonary Center, Boston University School of Medicine, Department of Surgery, Thfts University School of Medicine, Boston, Massachusetts. 2 Supported by the Veterans Administration Research Service. 3 Correspondence and requests for reprints should be addressed to Bartolome R. Celli, M.D., Chief, Pulmonary Section, Department of Veterans Affairs Medical Center, 150 South Huntington Avenue, Boston, MA 02130.
Fig. 1. Posteroanterior chest roentgenogram obtained before surgical plication. The left hemidiaphragm is elevated because of unilateral paralysis.
797
798
CASE REPORT
TABLE 2 EFFECTS OF PLICATION ON DIAPHRAGMATIC STRENGTH AND MAXIMAL VOLUNTARY VENTILATION IN A PATIENT WITH UNILATERAL DIAPHRAGMATIC PARALYSIS After Plication
6/89 Pdi max, cm H2O Pplmax, cm H2O Pg max, cm H2O MVV, Llmin
30
-34 -4 74
6/90 59 -57 +2
10/90
3/91
51 -48 +3
75
-77 -2
188
123
Definition of abbreviations: Pdimax =
maximal transdiaphragmatic pressure; Pplmax = maximal inspiratory pleural pressure; Pgmax = maximalinspiratory gastricpressure; MVV = maximal voluntary ventilation.
Fig. 2. Posteroanterior chest roentgenogram obtained after surgical plication. Notice the return of the left hemidiaphragm to a more normal position.
imately 1 yr after plication shows the left hemidiaphragm in a near normal position. Results of pulmonary function studies, DLcO, and arterial blood gas measurements are presented in table 1. At baseline, the patient demonstrated a restrictive pattern, with low FVC, FEV 1, but normal FEV1/FVC. After plication, the FVC and FEV 1improved rapidly over the next 2 months. At 20 months it had reached 88070 of predicted. Although in the low normal predicted range prior to plication, TLC and FRC also improved but residual volume remained unchanged. Along with an improvement in lung volumes, the DLCO increased from a baseline of 17.6 to 25.5 mllmin/mm Hg (81% of predicted). Arterial Po 2 also improved, from 70 to 87 mm Hg, 20 months after surgery. The ventilatory muscle studies are summarized in table 2. Diaphragmatic strength as expressed by
the Pdi max increased from 30 to 59 cm H 20 at 2 months, and to 75 cm H 20 at 20 months. MVV also improved, from a baseline of 74 L/min (50% of predicted) to 118 L/min at 2 months and to 123 L/min (78% predicted) at 20 months postplication. It can be seen in figure 3 that the ventilatory muscle recruitment pattern also changed; ~/PgI~Ppl changed from an abnormal positive to a more normal negative value, consistent with more effective inspiratory diaphragmatic recruitment during tidal breathing, falling within the normal range as described by others (3, 4).
Discussion This study showed that surgical plication of the left hemidiaphragm in a patient with symptomatic unilateral diaphragmatic paral-
TABLE 1
ysisresults in clinical and physiologicimprovement. Vital capacity, lung volumes and Pa02 increased progressively after surgery. This was associated with an increase in diaphragmatic strength and MVV. There was a change in ventilatory muscle recruitment to more effective diaphragmatic recruitment during inspiration. Patients with unilateral diaphragmatic paralysis have been shown to have low VC, FEV 1 and FVC (1-11). The patient in this report manifested similar reductions in FVC and FEV 1, the values of which remained decreased until the time of surgery. Although in our patient, reductions in TLC and FRC were not demonstrated by comparison to the predicted normal values, reductions in TLC and FRC have been reported in patients prior to plication (5,6). In these reports, plication resulted in an increase in TLC, FRC, and spirometric lung volumes, whereas residual volume, as in our patient, remained unchanged (5, 6). The improvement in lung volumes has been shown to persist for as long as 10yr after surgery (6). Arterial Po2has been reported to be reduced in unilateral diaphragmatic paralysis (3, 6), and it improves after plication. In our patient, Pa02 also improved (table 1). The improvement in gas exchange is most likely due to the change in the configuration and function of the diaphragm, resulting in less atelecta-
EFFECT OF SURGICAL PLICATION ON SPIROMETRIC VALUES, LUNG VOLUMES, AND BLOOD GAS DETERMINATION IN A PATIENT WITH UNILATERAL DIAPHRAGMATIC PARALYSIS· Before Plication
10/88 FVC, L FEV 1 , L FEV 1/FVC TLC, L IC, L FRC, L RV, L ERV, L OLeo, mllmin/mm Hg pH Pao2, mm Hg Paeo2, mm Hg
3.59 (60) 2.69 (59) 0.74
4/89 3.34 (56) 2.43 (54) 0.73
7.46 70 35
13
After Plication
4/90
5/90
3.52 (59) 2.63 (59) 0.75 6.64 (80) 2.30 (62) 4.34 (94) 3.44 (144) 0.90 (40) 17.6 (54)
4.17 (70) 3.24 (73) 0.78 6.89 (83) 2.70 (73) 4.19 (91) 2.89 (121) 1.30 (58) 23.4 (73)
6/90 4.82 (81) 3.55 (80) 0.74
7.45 79 32
3/91 5.22 (88) 3.73 (85) 0.71 8.4 (101) 3.3 (90) 5.1 (110) 3.2 (135) 1.9 (85) 25.5 (80) 7.41 87 38
Definition of abbreviations: Ie = inspiratory capacity;RV = residual volume; ERV = expiratory reserve volume; OLeo = single· breath eo diffusingcapacity. • Values in parentheses indicatepercent predicted.
E
a
N J:
1
10
o e,
'"
.~o o •
7+-------+-------+---12
-2
Fig. 3. Plots of gastric versus pleural pressure changes during tidal breathing before (open circles) and after (closedcircles)plication for unilateral diaphragmatic paralysis. I = end of inspiration; E = end of expiration. The change in slope from a positive to a negative value indicates more effective diaphragmatic recruitment during tidal breathing .
799
CASE REPORT
sis, increased lung volume, and improved ventilation/perfusion ratios. Although not specifically commented upon, DLco in one study showed a slight reduction (85070 of predicted), which improved after plication (6). In our patient, DLCO also improved to a similar degree, but the baseline value was lower than the value reported in that study (14). The mechanisms for the improved respiratory mechanics after diaphragmatic plication, for both unilateral and bilateral diaphragmatic paralysis, have been given little attention. Proposed hypotheses for the improved respiratory mechanics include: (1) a change in the configuration of the diaphragm, (2) increased ability of the diaphragm to act as a pressure generator, or (3) a combination of both. Schoenfeld and coworkers (7) measured Pdi in a 2-yr-old girl with idiopathic peripheral neuropathy and bilateral diaphragmatic paralysis, and they found no increase after plication (7). Because lung volume (as measured by chest roentgenogram) increased after the procedure, these investigators suggested that the improved respiratory function resulted only from a change in diaphragmatic configuration. Takeda and coworkers (15) studied dogs with bilaterally induced diaphragmatic paralysis and showed an increase in tidal volume but no increase in Pdi max after plication. These findings are consistent with the observation of increased lung volume without a change in diaphragmatic pressure generation, as in the patient described earlier (7). Because the respiratory muscle physiology in bilateral diaphragmatic paralysis is different from that in unilateral diaphragmatic paralysis (3, 4), we reasoned that plication of the affected side would improve the ability of the hemidiaphragm to act as a pressure generator. Another study by Thkedaand coworkers(16) supported our contention. These investigators studied dogs with unilaterally induced diaphragmatic paralysis, and they showed a significant increase in Pdi max after plication. The baseline value of Pdi max in our patient was similar to those reported in the literature (3, 4). The large increase after plication brought the value close to but not within the normal range seen in our laboratory (range, 110to 250 em H 2 0 ). Although the case we report is the first one in which a patient has undergone systematical evaluation of respiratory muscle function, wediscovereda study that contained one patient evaluated before and after plication for a flaccid right hemidiaphragm (4). Although the patient was not discussed in terms of the effect of the plica-
tion, the investigators did show an increase in Pdi max , from 33 to 53 em H 2 0 , similar to the results in our patient. The mechanism for the increased Pdi max after plication for unilateral paralysis might be explained as follows: In the paralyzed state, as the right hemidiaphragm descends during inspiration, the gastric pressure would not be expectedto increase normally because the flaccid left diaphragm develops paradoxical motion, resulting in a decreased volume of air to the left lung. After plication, the left hemidiaphragm is less compliant. As the right hemidiaphragm descends during inspiration, Pg increases, with a resulting smaller decrease in volume of the left lung. It is also possible that the stabilized left hemidiaphragm better opposed the expanding action of other inspiratory muscles of the rib cage. Not only was the strength of the diaphragm increased but there was also an improvement in overall respiratory muscle function. MVV increased from 79 to 123 L/min, representing a 55% increase. The best explanation for the increase in MVV is the increase in force reserve. It is known that the factors that determine diaphragmatic fatigability are the ratio of pressure developed over maximal pressure (PdilPdimax) times the duration of inspiration as a function of total respiratory time (n/Ttot). The increase in Pdi max , when all the other factors remained equal, must have resulted in a drop in tension time index and hence in fatigability. Finally, plication also resulted in changes in the pattern of ventilatory muscle recruitment. Unilateral diaphragmatic paralysis is characterized by increased use of intercostal and accessory inspiratory muscles (3, 4, 18, 19). On the basis of the results of the ventilatory muscle studies during tidal breathing in our patient, paradoxical diaphragmatic motion was demonstrated before plication. This is best shown in figure 1where the dPg/dPpl plots reveal a positive slope. Plication resulted in normalization of the slope, which now became negative as seen in normal subjects (3, 4). The capacity to better recruit the diaphragm helps explain the improved mechanics and blood gases as more ventilation reached the bases. In summary, we have shown that plication of the affected hemidiaphragm in unilateral paralysis results in symptomatic clinical and physiologic improvement. The improvement in pulmonary function, gas exchange, and respiratory muscle function is best explained by the increased strength and endurance of
the plicated diaphragm. These results support the use of surgical plication for patients with symptomatic unilateral diaphragm paralysis.
References 1. Piehler JM, Pairolero PC, Gracey DR, Bernatz PE. Unexplained diaphragmatic paralysis. J Thorac
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