Persistent By James
Pulmonary Adenomatoid
B. Atkinson,
Edward
Hypertension Malformation
G. Ford, Hiroaki
Kitagawa,
Complicating in Neonates Kevin P. Lally, and Bridget
Cystic Humphries
Los Angeles, California and Lackland AFB, Texas l Neonates with congenital diaphragmatic hernia (CDH) are known to be susceptible to stress-induced persistent pulmonary hypertension (PPHN). Congenital cystic adenomatoid malformations (CCAMs) may also present as respiratory distress in the newborn. lntubation and mechanical ventilation cause clinical deterioration because of air trapping within cystic spaces; these patients require prompt lobectomy. PPHN has not been commonly associated with CCAM. Three patients with CCAM were encountered who developed PPHN postlobectomy. Three newborns, 36 to 38 weeks’ gestation, presented with respiratory distress. Two had diagnosis of thoracic tumors on fetal ultrasound (22 and 33 weeks). Chest x-ray at birth confirmed cystic intrathoracic tumors in all and they underwent immediate thoracotomy and lobectomy (1 right upper, 1 left lower, 1 left upper). The patients were stable for 4 hours to 5 days postoperatively and then developed findings consistent with PPHN by cardiac echocardiography and required extracorporeal membrane oxygen (ECMO) support. ECMO was required for 66.5 to 120 hours. Each patient was successfully weaned to conventional ventilatory support. The clinical course of these patients was similar to those with CDH who undergo immediate surgery. The stress of surgical intervention combined with hypoxia and hypercarbia stimulates a hyperactive pulmonary vasculature and the development of PPHN. ECMO provides an effective adjunct to support patients with PPHN on the basis of congenital cystic adenomatoid malformations. Copyright o 1992 by W.B. Saunders Company INDEX WORDS: Cystic adenomatoid tent pulmonary hypertension.
malformation,
persis-
C tion (CCAM) of the lungs is considered in the differential diagnosis of neonates with respiratory ONGENITAL
cystic adenomatoid
malforma-
mechanical problem. Three patients are reported who postoperatively developed alterations in oxygenation and ventilation consistent with a persistent pulmonary hypertension (PPHN). These patients eventually required extracorporeal membrane oxygenation (ECMO) support. CASE
REPORTS
Case 1 A 3.8-kg full-term infant was the product of a pregnancy complicated by urinary tract vaginal infections, and a ruptured ovarian cyst. One-minute Apgar was 5 and the patient was intubated because of respiratory distress. Chest roentgenogram showed a cystic mass in the left hemithorax, shift of the heart to the right, and the nasogastric tube below the diaphragm. A small amount of contrast placed into the stomach showed the gastrointestinal tract below the diaphragm. Diagnosis of CCAM was made and the patient underwent immediate thoracotomy and left upper lobectomy. The lesion was of pathological type I with large cysts requiring total lobectomy (Figs 1 and 2). There was immediate improvement of ventilatory status with thoracotomy. The patient remained stable until 3 hours postoperatively when severe hypoxia developed in spite of increasing mean airway pressures. The pH dropped to 6.97 and the oxygen index increased from 34 to 40. Cardiac echo confirmed findings of pulmonary hypertension with right-to-left shunting in the foramen ovate and patent ductus. Oxygen index is defined as the product of the mean airway pressure times the inspired oxygen concentration divided by the arterial PO,. Conventional ventilatory support is known to have a mortality of 85% without ECMO with an oxygen index of 35 or greater. The patient was placed on ECMO for pulmonary hypertension. The patient developed a hemothorax due to heparinization, which required repeat thoracotomy at 2 days to relieve intrathoracic pressure. The patient required 113 hours of ECMO, then was
distress who require intubation and mechanical ventilatory support. Clinical deterioration following intubation is usually the result of air trapping within cystic spaces with the resulting intrathoracic mass-effect impairing ventilation and venous return to the heart. Successful management requires prompt thoracotomy and removal of the involved pulmonary tissue. Improvement is usually prompt with relief of the
From the Division of Pediatric Surgery, Children’s Hospital of Los Angeles, University of Southern California School of Medicine, Los Angeles, CA, and the Department of Surgery, Wilford Hall USAF Medical Center, LacklandAFB, TX. Date accepted: September 6, 1990. Address reprint requests to James B. Atkinson, MD, Children’s Hospital of Los Angeles, 4650 Sunset Bfvd, Los Angeles, CA 90027. Copyright o 1992 by W. B. Saunders Company 0022-3468/92/2701-0014$03.00/0
54
Fig 1. The resectedspecimen of case 1 is pictured with large cysts replacingthe entire lobe.
Journalof Pediatric Surgery, Vol 27, No 1 (January), 1992: pp 54-56
PULMONARY HYPERTENSION
55
IN CCAM
immediate improvement of cardiac output and oxygenation. Again the lesion was pathological type I requiring lobectomy. Four hours postoperatively the patient experienced progressive impairment of oxygenation and cardiac echo showed severe PPHN with right-toleft shunt. The child required ECMO support at 24 hours of age. The patient was supported on bypass for 92 hours and was decannulated because of a small intraparenchymal posterior occipital central nervous system hemorrhage. The PPHN had sufficiently resolved during bypass to allow adequate postdecannulation maintenance with conventional ventilatory management. Arterial blood gases and clinical course are summarized in Tables 1 and 2.
Case 3 A 3.5kg infant was the full-term product of an uncomplicated pregnancy. Fetal ultrasound at 22 weeks showed polyhydramnios, a solid abdominal mass, and displacement of the heart into the right thorax. Physical examination at birth showed a 4- to S-cm palpable liver and some anatomic flaring of the right chest. Chest roentgenogram showed the heart in the right hemithorax, the nasogastric tube below the diaphragm, aeration of the bowel. and no indication of diaphragmatic hernia. A second chest roentgenogram showed cystic aeration of the left lower lobe consistent with CCAM. The patient underwent a left thoracotomy and left lower lobectomy at 18 hours of age with immediate improvement of pulmonary status. The patient was ventilated for 3 days postoperatively with increasing F,O1 and inspiratory pressure requirements. On postoperative day 5 the patient was transferred for ECMO support with a pH of 7.44, PO, of 17, PCOZ of 27 on 100% F,O, and peak ventilatory pressures of 40. Cardiac echo again confirmed the diagnosis of pulmonary hypertension. The patient’s oxygen index was 78. The patient was supported on bypass for 66 hours with slow resolution of the PPHN and an uncomplicated decannulation. Arterial blood gas and clinical course are summarized in Tables 1 and 2.
DISCUSSION Fig 2. The photomicrograph shows mucin producing cells lining the cysts. Also noted is a pulmonary arteriole with marked smooth muscular thickening.
slowly weaned from bypass and decannulated without complication. The patient’s arterial blood gases and course are summarized in Tables 1 and 2.
Case 2 A 3.0%kg infant was diagnosed with a cystic thoracic mass at 33-week fetal ultrasound. The mother was transferred to a medical center for high-risk obstetric management. The infant tolerated labor well but had an initial Apgar of 4 and was immediately intubated. The child showed marginal oxygenation because of progressive gas trapping within a cystic right lung lesion identified on chest roentgenogram. Cardiac echo was normal and the patient was supported with high-frequency ventilation. Serial chest roentgenograms showed progressive gas trapping and compression of the contralateral lung. The patient underwent thoracotomy and resection of a right upper lobe CCAM at 20 hours of age with an
CCAMs of the lungs in neonates are unusual but must be considered in the differential diagnosis of neonatal respiratory distress. Chest roentgenograms showing diffuse multicystic areas within one hemithorax limits the differential to congenital diaphragmatic hernia (CDH) or CCAM. A small amount of contrast placed into a nasogastric tube will usually show the gastrointestinal tract to lie above or below the diaphragm and differentiate CDH from CCAM. The distinction is important because initial management and surgical approach are disparate between CDH and CCAM, and are not interchangeable. Patients with CDH suffer primarily a physiological aberration in which PPHN is stimulated by acidosis and hypoxia. Immediate surgical intervention may worsen the hypertension until the hypoxia and acidosis have been corrected.’ Immediate surgical interven-
Table 1. Cystic Adenomatoid Case NO.
Birth Weight(g)
Gestational Age (wkl
Malformation Time of
Apgar (1 and 5 min)
Ste of CCAM
Lobectomy
Outcome
Immediate
Survived
1
3,800
42
5 and 9
Left upper lobe
2
3,080
36
4and7
Right upper lobe
20 h
Survived
3
3,550
41
7 and 9
Leh lower lobe
18h
Survived
56
ATKINSON ET AL
Table 2. CCAM and ECMO Arterial Blood Gases Prior to ECMO
C.Se
Time of
Age On
Hours On
NO.
PH
PO2
PCO,
MAP
01
Lobectomy
ECMO
ECMO
1
6.97
28
108
10
40
Immediate
17h
113h
2
7.06
17
75
12
71
20 h
24h
92 h
3
7.44
17
27
13
78
18h
144h
66 h
tion in CDH was originally thought to enhance survival; however, recent data suggest that immediate intervention worsens or prolongs PPHN, worsens pulmonary compliance, and stimulates release of circulating pulmonary vascular constrictors that further aggravate pulmonary vascular resistance.2.3 CCAMs of neonates may be divided into three types. Type 1 is most common (55%) and consists of large cystic spaces within one lung lobe. All three cases in this series were type I. Type 2 is composed of numerous smaller cysts measuring 1 to 10 mm in diameter and represents approximately 40% of cases. The remaining cases are type 3, manifested by solid masses of tissue without gross cyst formation.4.5 Patients with CCAM whose respiratory distress necessitates intubation must be considered for emergent thoracotomy and lobectomy. Immediate surgical intervention is indicated in the intubated patient, because mechanical ventilatory support causes air trapping within the cystic spaces, overdistention of the cysts, mediastinal herniation of the affected lobe, and impairment of pulmonary and systemic venous cardiac return and subsequent cardiopulmonary arrest.’ These patients typically have a progressive downhill clinical course following intubation until thoracotomy can be performed. In most cases there is an immediate clinical improvement with return of normal cardiac output. We present three patients who had respiratory distress at birth and required intubation and mechanical ventilation. Chest roentgenograms showed CCAM. Each patient was taken to the operating suite for early thoracotomy and lobectomy and each did predictably well immediately postoperatively. These three patients are unusual because at various times postoperatively they developed diffi-
culty in oxygenation and ventilation. The ventilatory defects were progressive and the changes were similar to those patients with CDH who develop postoperative PPHN. At this institution, neonates with respiratory distress are stratified to severe or moderate PPHN by oxygenation index (01). The 01 relates mean airway pressure (MAP) and inspired oxygen content (F,O,) with arterial oxygenation (PAO,) as an indicator of oxygen delivery across the alveolar membrane (01 = MAP x F,O,)/PAO, x 100. An 01 ~40 is considered mild to moderate PPHN, whereas 01 >40 indicates severe PPHN with an expected mortality of 80%. Neonates with an 01 >40 and satisfying rigid selection criteria are candidates for ECMO support. Each of the present patients qualified for ECMO and were managed on bypass. To our knowledge this is the first report of neonates with CCAM who have undergone lobectomy then developed PPHN and were successfully managed with ECMO. The reasons for development of PPHN are not entirely clear. Pathological evaluation of a large series of infants with a CCAM show pulmonary blood vessels to be microscopically normal in all classification types.’ However, the photomicrograph in Fig 2 does suggest pulmonary artery initial hyperplasia in this case. These cases of PPHN in infants with CCAM suggest that the arteriolar segments of the pulmonary vascular bed may be highly reactive to combinations of acidosis, hypoxia, hypothermia, and stress-induced release of circulating factors (catecholamines, thromboxane). Extracorporeal support provides an effective adjunct in management of neonates with anatomic aberrations of pulmonary development (CDH, CCAM) who develop stressinduced PPHN.
REFERENCES 1. Cartlidge PHT, Mann NP, Kapila L: Preoperative stabilization in congenital diaphragmatic hernia. Arch Dis Child 61:12261228,1986 2. Sakai H, Tamura M, Hosokawa Y. et al: Effect of surgical repair on respiratory mechanics in congenital diaphragmatic hernia. J Pediatr 111:432-438,1987 3. Ford WD, James MJ, Walsh JA: Congenital diaphragmatic hernia: Association between pulmonary vascular resistance and plasma thromboxane concentrations. Arch Dis Child 59:143-146, 1984
4. Miller RK, Sieber WK, Yunis EJ: Congenital adenomatoid malformation of the lung. A report of 17 cases, and review of the literature, in Sommers SC, Rosen PP teds): Pathology Annual, Part I. East Norwalk, CT, Appleton-Century-Crofts, 1980, pp 387-407 5. Stocker JT, Madewell JE, Drake RM: Congenital cystic adenomatoid malformation of the lung. Classification and morphologic spectrum. Hum Path01 8:155-171, 1977 6. Adzick NS, Harrison MR, Glick PL, et al: Fetal cystic adenomatoid malformation: Prenatal diagnosis and natural history. J Pediatr Surg 20:483-488. 1985
Pulmonary Adenomatoid
B. Atkinson,
Edward
Hypertension Malformation
G. Ford, Hiroaki
Kitagawa,
Complicating in Neonates Kevin P. Lally, and Bridget
Cystic Humphries
Los Angeles, California and Lackland AFB, Texas l Neonates with congenital diaphragmatic hernia (CDH) are known to be susceptible to stress-induced persistent pulmonary hypertension (PPHN). Congenital cystic adenomatoid malformations (CCAMs) may also present as respiratory distress in the newborn. lntubation and mechanical ventilation cause clinical deterioration because of air trapping within cystic spaces; these patients require prompt lobectomy. PPHN has not been commonly associated with CCAM. Three patients with CCAM were encountered who developed PPHN postlobectomy. Three newborns, 36 to 38 weeks’ gestation, presented with respiratory distress. Two had diagnosis of thoracic tumors on fetal ultrasound (22 and 33 weeks). Chest x-ray at birth confirmed cystic intrathoracic tumors in all and they underwent immediate thoracotomy and lobectomy (1 right upper, 1 left lower, 1 left upper). The patients were stable for 4 hours to 5 days postoperatively and then developed findings consistent with PPHN by cardiac echocardiography and required extracorporeal membrane oxygen (ECMO) support. ECMO was required for 66.5 to 120 hours. Each patient was successfully weaned to conventional ventilatory support. The clinical course of these patients was similar to those with CDH who undergo immediate surgery. The stress of surgical intervention combined with hypoxia and hypercarbia stimulates a hyperactive pulmonary vasculature and the development of PPHN. ECMO provides an effective adjunct to support patients with PPHN on the basis of congenital cystic adenomatoid malformations. Copyright o 1992 by W.B. Saunders Company INDEX WORDS: Cystic adenomatoid tent pulmonary hypertension.
malformation,
persis-
C tion (CCAM) of the lungs is considered in the differential diagnosis of neonates with respiratory ONGENITAL
cystic adenomatoid
malforma-
mechanical problem. Three patients are reported who postoperatively developed alterations in oxygenation and ventilation consistent with a persistent pulmonary hypertension (PPHN). These patients eventually required extracorporeal membrane oxygenation (ECMO) support. CASE
REPORTS
Case 1 A 3.8-kg full-term infant was the product of a pregnancy complicated by urinary tract vaginal infections, and a ruptured ovarian cyst. One-minute Apgar was 5 and the patient was intubated because of respiratory distress. Chest roentgenogram showed a cystic mass in the left hemithorax, shift of the heart to the right, and the nasogastric tube below the diaphragm. A small amount of contrast placed into the stomach showed the gastrointestinal tract below the diaphragm. Diagnosis of CCAM was made and the patient underwent immediate thoracotomy and left upper lobectomy. The lesion was of pathological type I with large cysts requiring total lobectomy (Figs 1 and 2). There was immediate improvement of ventilatory status with thoracotomy. The patient remained stable until 3 hours postoperatively when severe hypoxia developed in spite of increasing mean airway pressures. The pH dropped to 6.97 and the oxygen index increased from 34 to 40. Cardiac echo confirmed findings of pulmonary hypertension with right-to-left shunting in the foramen ovate and patent ductus. Oxygen index is defined as the product of the mean airway pressure times the inspired oxygen concentration divided by the arterial PO,. Conventional ventilatory support is known to have a mortality of 85% without ECMO with an oxygen index of 35 or greater. The patient was placed on ECMO for pulmonary hypertension. The patient developed a hemothorax due to heparinization, which required repeat thoracotomy at 2 days to relieve intrathoracic pressure. The patient required 113 hours of ECMO, then was
distress who require intubation and mechanical ventilatory support. Clinical deterioration following intubation is usually the result of air trapping within cystic spaces with the resulting intrathoracic mass-effect impairing ventilation and venous return to the heart. Successful management requires prompt thoracotomy and removal of the involved pulmonary tissue. Improvement is usually prompt with relief of the
From the Division of Pediatric Surgery, Children’s Hospital of Los Angeles, University of Southern California School of Medicine, Los Angeles, CA, and the Department of Surgery, Wilford Hall USAF Medical Center, LacklandAFB, TX. Date accepted: September 6, 1990. Address reprint requests to James B. Atkinson, MD, Children’s Hospital of Los Angeles, 4650 Sunset Bfvd, Los Angeles, CA 90027. Copyright o 1992 by W. B. Saunders Company 0022-3468/92/2701-0014$03.00/0
54
Fig 1. The resectedspecimen of case 1 is pictured with large cysts replacingthe entire lobe.
Journalof Pediatric Surgery, Vol 27, No 1 (January), 1992: pp 54-56
PULMONARY HYPERTENSION
55
IN CCAM
immediate improvement of cardiac output and oxygenation. Again the lesion was pathological type I requiring lobectomy. Four hours postoperatively the patient experienced progressive impairment of oxygenation and cardiac echo showed severe PPHN with right-toleft shunt. The child required ECMO support at 24 hours of age. The patient was supported on bypass for 92 hours and was decannulated because of a small intraparenchymal posterior occipital central nervous system hemorrhage. The PPHN had sufficiently resolved during bypass to allow adequate postdecannulation maintenance with conventional ventilatory management. Arterial blood gases and clinical course are summarized in Tables 1 and 2.
Case 3 A 3.5kg infant was the full-term product of an uncomplicated pregnancy. Fetal ultrasound at 22 weeks showed polyhydramnios, a solid abdominal mass, and displacement of the heart into the right thorax. Physical examination at birth showed a 4- to S-cm palpable liver and some anatomic flaring of the right chest. Chest roentgenogram showed the heart in the right hemithorax, the nasogastric tube below the diaphragm, aeration of the bowel. and no indication of diaphragmatic hernia. A second chest roentgenogram showed cystic aeration of the left lower lobe consistent with CCAM. The patient underwent a left thoracotomy and left lower lobectomy at 18 hours of age with immediate improvement of pulmonary status. The patient was ventilated for 3 days postoperatively with increasing F,O1 and inspiratory pressure requirements. On postoperative day 5 the patient was transferred for ECMO support with a pH of 7.44, PO, of 17, PCOZ of 27 on 100% F,O, and peak ventilatory pressures of 40. Cardiac echo again confirmed the diagnosis of pulmonary hypertension. The patient’s oxygen index was 78. The patient was supported on bypass for 66 hours with slow resolution of the PPHN and an uncomplicated decannulation. Arterial blood gas and clinical course are summarized in Tables 1 and 2.
DISCUSSION Fig 2. The photomicrograph shows mucin producing cells lining the cysts. Also noted is a pulmonary arteriole with marked smooth muscular thickening.
slowly weaned from bypass and decannulated without complication. The patient’s arterial blood gases and course are summarized in Tables 1 and 2.
Case 2 A 3.0%kg infant was diagnosed with a cystic thoracic mass at 33-week fetal ultrasound. The mother was transferred to a medical center for high-risk obstetric management. The infant tolerated labor well but had an initial Apgar of 4 and was immediately intubated. The child showed marginal oxygenation because of progressive gas trapping within a cystic right lung lesion identified on chest roentgenogram. Cardiac echo was normal and the patient was supported with high-frequency ventilation. Serial chest roentgenograms showed progressive gas trapping and compression of the contralateral lung. The patient underwent thoracotomy and resection of a right upper lobe CCAM at 20 hours of age with an
CCAMs of the lungs in neonates are unusual but must be considered in the differential diagnosis of neonatal respiratory distress. Chest roentgenograms showing diffuse multicystic areas within one hemithorax limits the differential to congenital diaphragmatic hernia (CDH) or CCAM. A small amount of contrast placed into a nasogastric tube will usually show the gastrointestinal tract to lie above or below the diaphragm and differentiate CDH from CCAM. The distinction is important because initial management and surgical approach are disparate between CDH and CCAM, and are not interchangeable. Patients with CDH suffer primarily a physiological aberration in which PPHN is stimulated by acidosis and hypoxia. Immediate surgical intervention may worsen the hypertension until the hypoxia and acidosis have been corrected.’ Immediate surgical interven-
Table 1. Cystic Adenomatoid Case NO.
Birth Weight(g)
Gestational Age (wkl
Malformation Time of
Apgar (1 and 5 min)
Ste of CCAM
Lobectomy
Outcome
Immediate
Survived
1
3,800
42
5 and 9
Left upper lobe
2
3,080
36
4and7
Right upper lobe
20 h
Survived
3
3,550
41
7 and 9
Leh lower lobe
18h
Survived
56
ATKINSON ET AL
Table 2. CCAM and ECMO Arterial Blood Gases Prior to ECMO
C.Se
Time of
Age On
Hours On
NO.
PH
PO2
PCO,
MAP
01
Lobectomy
ECMO
ECMO
1
6.97
28
108
10
40
Immediate
17h
113h
2
7.06
17
75
12
71
20 h
24h
92 h
3
7.44
17
27
13
78
18h
144h
66 h
tion in CDH was originally thought to enhance survival; however, recent data suggest that immediate intervention worsens or prolongs PPHN, worsens pulmonary compliance, and stimulates release of circulating pulmonary vascular constrictors that further aggravate pulmonary vascular resistance.2.3 CCAMs of neonates may be divided into three types. Type 1 is most common (55%) and consists of large cystic spaces within one lung lobe. All three cases in this series were type I. Type 2 is composed of numerous smaller cysts measuring 1 to 10 mm in diameter and represents approximately 40% of cases. The remaining cases are type 3, manifested by solid masses of tissue without gross cyst formation.4.5 Patients with CCAM whose respiratory distress necessitates intubation must be considered for emergent thoracotomy and lobectomy. Immediate surgical intervention is indicated in the intubated patient, because mechanical ventilatory support causes air trapping within the cystic spaces, overdistention of the cysts, mediastinal herniation of the affected lobe, and impairment of pulmonary and systemic venous cardiac return and subsequent cardiopulmonary arrest.’ These patients typically have a progressive downhill clinical course following intubation until thoracotomy can be performed. In most cases there is an immediate clinical improvement with return of normal cardiac output. We present three patients who had respiratory distress at birth and required intubation and mechanical ventilation. Chest roentgenograms showed CCAM. Each patient was taken to the operating suite for early thoracotomy and lobectomy and each did predictably well immediately postoperatively. These three patients are unusual because at various times postoperatively they developed diffi-
culty in oxygenation and ventilation. The ventilatory defects were progressive and the changes were similar to those patients with CDH who develop postoperative PPHN. At this institution, neonates with respiratory distress are stratified to severe or moderate PPHN by oxygenation index (01). The 01 relates mean airway pressure (MAP) and inspired oxygen content (F,O,) with arterial oxygenation (PAO,) as an indicator of oxygen delivery across the alveolar membrane (01 = MAP x F,O,)/PAO, x 100. An 01 ~40 is considered mild to moderate PPHN, whereas 01 >40 indicates severe PPHN with an expected mortality of 80%. Neonates with an 01 >40 and satisfying rigid selection criteria are candidates for ECMO support. Each of the present patients qualified for ECMO and were managed on bypass. To our knowledge this is the first report of neonates with CCAM who have undergone lobectomy then developed PPHN and were successfully managed with ECMO. The reasons for development of PPHN are not entirely clear. Pathological evaluation of a large series of infants with a CCAM show pulmonary blood vessels to be microscopically normal in all classification types.’ However, the photomicrograph in Fig 2 does suggest pulmonary artery initial hyperplasia in this case. These cases of PPHN in infants with CCAM suggest that the arteriolar segments of the pulmonary vascular bed may be highly reactive to combinations of acidosis, hypoxia, hypothermia, and stress-induced release of circulating factors (catecholamines, thromboxane). Extracorporeal support provides an effective adjunct in management of neonates with anatomic aberrations of pulmonary development (CDH, CCAM) who develop stressinduced PPHN.
REFERENCES 1. Cartlidge PHT, Mann NP, Kapila L: Preoperative stabilization in congenital diaphragmatic hernia. Arch Dis Child 61:12261228,1986 2. Sakai H, Tamura M, Hosokawa Y. et al: Effect of surgical repair on respiratory mechanics in congenital diaphragmatic hernia. J Pediatr 111:432-438,1987 3. Ford WD, James MJ, Walsh JA: Congenital diaphragmatic hernia: Association between pulmonary vascular resistance and plasma thromboxane concentrations. Arch Dis Child 59:143-146, 1984
4. Miller RK, Sieber WK, Yunis EJ: Congenital adenomatoid malformation of the lung. A report of 17 cases, and review of the literature, in Sommers SC, Rosen PP teds): Pathology Annual, Part I. East Norwalk, CT, Appleton-Century-Crofts, 1980, pp 387-407 5. Stocker JT, Madewell JE, Drake RM: Congenital cystic adenomatoid malformation of the lung. Classification and morphologic spectrum. Hum Path01 8:155-171, 1977 6. Adzick NS, Harrison MR, Glick PL, et al: Fetal cystic adenomatoid malformation: Prenatal diagnosis and natural history. J Pediatr Surg 20:483-488. 1985
