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Objective: To describe the interaction of spontaneous breaths, manual ventilation, and tidal volumes (V(T)) during stabilization of infants with congenital diaphragmatic hernia (CDH) in the delivery room., Study Design: We studied infants with CDH receiving respiratory support at birth. Airway pressure, flow, and volume were measured, and each breath or inflation was analyzed. Each V(T) was classified as a manual inflation, a spontaneous breath, or a spontaneous breath coinciding with manual inflation on the basis of the timing of the pressure and flow waves., Results: Twelve infants had 2957 breaths suitable for analysis, with spontaneous breathing in 11 infants (92%). The mean (+/-SD) proportion of manual inflations was 41% (+/-24%), spontaneous breaths 43% (+/-25%), spontaneous but coinciding with manual inflation 16% (+/-12%). V(T) was significantly different for spontaneous breaths (3.8 +/- 1.9 mL/kg), spontaneous breaths coinciding with manual inflation (4.7 +/- 2.5 mL/kg), and manual inflations alone (2.6 +/- 1.6 mL/kg)., Conclusions: Most infants with CDH breathed spontaneously, and manual ventilation was mostly asynchronous. We observed large differences in tidal volumes between spontaneous breaths, manual inflations, or where these coincided, with manual inflations having the lowest V(T). Monitoring the respiratory pattern of these infants could improve respiratory support.

The aim of this study was to assess the impact of surfactant deficiency on the pathophysiology of congenital diaphragmatic hernia (CDH). Pregnant ewes were operated on at 80 days of gestation for creation of a diaphragmatic hernia in the lambs. Twenty-one lambs survived to be delivered by cesarean section and were studied. Compliance was improved when surface tension effects were removed by saline solution in lungs of both control animals and lambs with CDH; however, the lungs of the lambs with CDH still had significantly impaired compliance. In a second series of experiments, two groups were studied: a surfactant-treated and a control, nontreated group. Surfactant was given prophylactically into the liquid-filled lungs before the first breath. All lambs were paralyzed and sedated and their lungs mechanically ventilated with 100% oxygen for 30 minutes; gas exchange was then assessed, pressure-volume data were obtained, and compliance was calculated. Surfactant significantly improved gas exchange; arterial oxygen pressure increased from 39 +/- 11.4 to 316 +/- 53.6 mm Hg, arterial carbon dioxide pressure decreased from 148 to 63 mm Hg, and pH increased from 6.87 to 7.16 (p < 0.001). Lung volume at 25 cm H2O, functional residual capacity, and compliance were all increased (p < 0.02). Thus, in the CDH lamb model, pulmonary mechanics are impaired by both parenchymal and surfactant abnormalities. Both lung mechanics and gas exchange are markedly improved by exogenous surfactant therapy.

To determine whether preoperative stabilization and delay of operative repair of congenital diaphragmatic hernia (CDH) may decrease operative risk, we performed serial pulmonary function tests on 22 newborn infants with CDH and on four infants without pulmonary hypoplasia (two with ileal atresia and two with tracheoesophageal anomalies) who served as control subjects. We used 2 passive respiratory mechanics technique to measure respiratory system compliance. All patients with CDH had respiratory distress immediately after birth, and required mechanical ventilation. Thirteen babies underwent emergency repair (six survived, seven died); nine of them received extracorporeal membrane oxygenation (ECMO) after the operation (two survived, seven died). Operative repair was delayed deliberately for 2 to 11 days in nine infants with severe hypoxemia. Six immediately received ECMO for 4 to 10 days; one died of intraventricular hemorrhage, and five survived and later underwent surgical repair. The seventh patient did not receive ECMO but appeared to have respiratory distress syndrome of infancy and improved after administration of synthetic surfactant. Improvement was seen in two additional infants who received conventional assisted ventilation during a 48-hour delay before surgery, and survived. In all, eight of nine infants who underwent preoperative stabilization survived (p less than 0.05 compared with survival after emergency surgery). Following surgical repair immediately after birth, respiratory system compliance improved only slightly during the first week of life, a time when control infants had a rapid increase in respiratory system compliance (p less than 0.001). In contrast, respiratory system compliance increased nearly twofold in the nine patients undergoing preoperative stabilization (p less than 0.02). Preoperative ECMO was associated with an increase in respiratory system compliance of more than 60% for 1 week, a significant difference from respiratory system compliance among patients undergoing emergency CDH repair (p less than 0.05). These observations provide physiologic evidence of possible benefits of preoperative stabilization before repair of CDH.

Delayed herniation of abdominal contents through a congenital diaphragmatic hernia may occur beyond the neonatal period. The case of a 29-month-old child with a Bochdalek hernia presenting as acute respiratory failure is presented. Chest radiography showed a tension gastrothorax that was misread as a tension pneumothorax. Tube thoracostomy resulted in clinical improvement by perforating and decompressing the stomach. Nasogastric tube placement confirmed herniation of the stomach into the left chest and is the initial treatment of choice when a tension gastrothorax is identified. A congenital diaphragmatic hernia must be recognized promptly so that rapid gastric decompression and surgical repair of the diaphragmatic defect can be performed.

One hundred two patients referred to our Esophageal Function Laboratory without endoscopic evidence of esophagitis were divided into two groups on the basis of the presence of a hiatal hernia on endoscopic examination. Fifty-three patients had a hiatal hernia and 49 did not. Both groups and 30 normal volunteer subjects had esophageal manometry and 24 hour esophageal pH monitoring. The incompetency of the cardia in patients with a hiatal hernia was dependent upon loss of components responsible for the antireflux mechanism, mainly a decrease in distal esophageal sphincter pressure and a decrease in the length of the sphincter exposed to the positive-pressure environment of the abdomen. These deficiencies were not related to the presence of a hiatal hernia and were similar to those of patients with an incompetent cardia without a hiatal hernia. Patients with a hiatal hernia and an incompetent cardia had significantly more esophageal exposure to refluxed acid than without a hiatal hernia. On the basis of the number of reflux episodes that lasted 5 minutes or longer and radioisotope transit studies, this increased acid exposure was due to both a loss of competency of the cardia and poor esophageal clearance secondary to the presence of a hiatal hernia. Reduction of the hernia and anchoring the distal esophagus into the abdomen not only may improve the antireflux mechanism, but corrects the clearance abnormality as well. The presence of a hiatal hernia has a detrimental effect on the clearance function of the body of the esophagus and may aggravate the effects of gastroesophageal reflux due to an incompetent cardia.

Some infants with congenital diaphragmatic hernia who die after surgical correction have a transient postoperative period during which systemic oxygenation is adequate (honeymoon period), whereas others have persistent hypoxemia. Using morphometric techniques, we analyzed lung structure, especially the arterial bed, in seven infants who died within 1 week of surgical repair. Three infants comprised the honeymoon group, the PaO2 transiently being greater than 150 mm Hg in the descending aorta (FiO2 1.0); four infants comprised the no-honeymoon group and never had PaO2 greater than 85 mm Hg. All lungs were hypoplastic for age; with one exception, infants in the no-honeymoon group had smaller lungs. Arterial structure in the no-honeymoon group contributed to a greater reduction in pulmonary arterial cross-sectional area. Each infant in the no-honeymoon group had muscularization of intra-acinar arteries and failure of perinatal increase in compliance of small preacinar arteries, features not seen in the honeymoon group or in the normal newborn infant. In addition, compared with the honeymoon group, luminal area of preacinar and intra-acinar arteries in the no-honeymoon group was decreased by reduced external diameter or increased medial thickness. Clinical deterioration in the honeymoon group is based on a vasoconstrictive response of the hypoplastic vascular bed. Persistent hypoxemia in the no-honeymoon group is based on both severity of pulmonary hypoplasia and structural remodeling of the pulmonary arteries.

The incidence of death from congenital diaphragmatic hernia appears to be unchanged in recent years despite advances in resuscitation, transport, and ventilatory support. Bilateral lung hypoplasia and abnormal pulmonary vascular reactivity as developmental consequences of the defect appear to play a major role in the continued high mortality rate. Recent advances in pharmacologic support have further elucidated the mechanisms of ventilatory failure in these patients and may represent means of improving survival in the future.

Lung volume and lung mechanics were measured in 19 infants, aged 2 to 8 weeks, with congenital pulmonary hypoplasia of various causes. These included nine infants with congenital diaphragmatic hernia, five infants with Werdnig-Hoffman disease of intrauterine onset, and five infants with isolated pulmonary hypoplasia or associated anomalies such as thoracic dystrophy and spina bifida. Infants were studied within the first two months of life in order to exclude the effects of natural adaptation and adverse influences such as lower respiratory tract infection. Lung volume and airway resistance were estimated by whole body plethysmography, total pulmonary resistance, and dynamic lung compliance with esophageal balloons and pneumotachography. Reductions in dynamic lung compliance were found in seven of the nine infants with congenital diaphragmatic hernia, probably reflecting lung overdistention after operative repair. Low airflow resistance was found in 12 infants, representing subjects from each category. The low airflow resistance may be related to reductions in airway generation number found when the disturbance of lung development occurs before 16 weeks of gestational age. This finding suggests a role for measurements of airflow resistance in characterizing the type of pulmonary hypoplasia.