Don K. Nakayama

Correction of congenital hydronephrosis in utero II. Decompression reverses the effects of obstruction on the fetal lung and urinary tract

Urethral obstruction and urachal ligation at 93-107 days gestation produced severe hydronephrosis, hydroureter, megacystis, and urinary ascites as well as significant pulmonary hypoplasia in 17 fetal lambs. Obstructions in 9 fetuses subsequently were relieved in utero by suprapubic cutaneous cystostomy. At birth, all 4 liveborn obstructed lambs had respiratory insufficiency, and only 1 survived. Four others were stillborn. The lungs were significantly hypoplastic by weight and volume (p less than 0.025). All 8 had advanced megacystis, hydroureter, and hydronephrosis but no cystic or dysplastic renal changes. In contrast, 7 liveborn lambs diverted in utero had far less respiratory difficulty and all survived (p = 0.002). Two were stillborn. The lung weight was significantly increased (p less than 0.05). All lambs undergoing in utero decompression showed significant resolution of the severe urinary tract dilatation seen in the obstructed lambs. In utero decompression of the obstructed fetal urinary tract allows the abnormally small lungs to grow and develop and hydronephrosis to resolve.

Chest injuries in childhood.

Differences in anatomy and mechanisms of injury are believed to contribute to the unique response of children to thoracic trauma. To characterize the scope and consequences of childhood chest injury, we reviewed the records of 105 children (ages 1 month to 17 years, mean 7.6 years) with chest injuries admitted to a level I pediatric trauma center from 1981 to 1988. Nearly all injuries (97.1%) were due to blunt trauma, and more than 50% were traffic related. Rib fractures, commonly multiple, and pulmonary contusions occurred with nearly equal frequency (49.5% and 53.3%, respectively), followed by pneumothorax (37.1%) and hemothorax (13.3%). One fourth of all pneumothoraces were under tension. Significant intrathoracic injuries occurred without rib fractures in 52% of cases with blunt trauma. Associated head, abdominal, and orthopedic injuries were present in 68.6% of children reviewed. One in five received endotracheal intubation and ventilatory support for 1 to 109 days. Presence or absence of head injury neither increased the need for respiratory support (29.4% vs. 17.2%, respectively; p = 0.24) nor affected the duration of support for those who were ventilated (6.8 +/- 8.9 days vs. 3.3 +/- 2.6 days, excluding one ventilator-dependent head-injured patient and five early deaths). The presence of associated injuries, intubation, and pneumothorax or hemothorax all resulted in significantly longer hospitalizations and more severe injury as measured by Injury Severity Score (ISS). Age, rib fracture, and contusion had no effect. Rarely encountered were ruptured diaphragm (2 cases), transection of the aorta (1), major tracheobronchial tears (3), flail chest (1), and cardiac contusion (2). Only two of the three children with penetrating injuries and three of the 83 (3.6%) with blunt injuries underwent chest operations. Six children (7%) died, one from a penetrating injury and five from blunt mechanisms. Chest Abbreviated Injury Scale (AIS) and ISS correlated significantly with mortality; age and head AIS did not. Rib fractures, lung contusions, and associated head, abdominal, and skeletal injuries are common because of the predominance of blunt-injury mechanisms. Nearly one half of chest injuries occurred without rib fractures. The need for ventilatory support is uncommon; when required, its duration is generally brief. Aortic transection, flail chest, and penetrating injuries more frequently encountered in adults and are uncommon in children. Thoracotomy generally is not required.(ABSTRACT TRUNCATED AT 400 WORDS)

Management of the fetus with congenital hydronephrosis

Twenty-six fetuses with dilated urinary tracts were studied with serial sonograms. Eight fetuses with unilateral hydronephrosis were followed without intervention; all are well after postnatal surgical correction. Three cases of bilateral hydronephrosis resolved spontaneously before birth. Eight fetuses with bilateral hydronephrosis had evidence of poor function: Three were not treated and died shortly after birth with small lungs and dysplastic kidneys; three others had diagnostic intervention that demonstrated irreversible disease and allowed termination of the pregnancy; two had obstruction successfully corrected in utero, but renal damage proved irreversible and precluded survival at birth. Seven fetuses with bilateral hydronephrosis and equivocal function underwent early decompression. Four were delivered early and corrected ex utero; 1 has renal failure and the other 3 are well. Three had obstruction relieved in utero by a catheter shunt placed percutaneously; 1 had multiple anomalies and died; the other 2 are well. Serial sonographic observation improves perinatal management of the fetus with a dilated urinary tract. The need for diagnostic or therapeutic intervention depends on the type and severity of obstruction and the time in gestation when it is discovered. Most fetuses do not require treatment before birth; a few may benefit from early decompression in or ex utero.

Prognosis of posterior urethral valves presenting at birth

Urethral obstruction due to posterior urethral valves (PUV) is a more lethal condition in the newborn than is commonly recognized. To study its prognosis when the diagnosis of PUV is made shortly after birth, cases of PUV presenting in the first week of life were reviewed. Eleven cases were seen at the University of California, San Francisco from 1974 to 1982. Five babies died, three within two hours of birth of respiratory insufficiency secondary to severe pulmonary hypoplasia, and two within three weeks with rapidly progressive renal failure. Of the six survivors, four exhibited respiratory difficulty (prolonged ventilatory support required in two, and bilateral pneumothoraces in two), three developed renal failure despite early urinary diversion, and one had renal tubular dysfunction. Only two infants had normal renal function after undergoing a successful series of reconstructions. Prune-belly syndrome and limb deformities were present in two surviving and two fatal cases. Although most cases of congenital hydronephrosis can be successfully treated after birth, those presenting in the newborn period represent a subset with high morbidity and mortality. With advances in prenatal diagnosis of congenital hydronephrosis, salvage of severe cases detected early in gestation may require more aggressive management in the prenatal period.

Etiology and outcome of pediatric burns

A 6-year retrospective review of burn victims hospitalized at a major burn center was conducted to determine the etiology and outcome of pediatric burns. Four hundred forty-nine patients under age 16 years were identified and stratified by age, sex, burn size, presence or absence of inhalation injury, cause of burn, and county of residence. The mean patient age was 4.3 +/- 0.2 years, and the male:female ratio was 1.9:1. There were 21 deaths overall (4.7%), the majority of which (18) were among children under 4 years of age. With respect to large burns, defined as > and = 30% total body surface area (TBSA), the mortality rate for children under age 4 was significantly higher than that for older children (46.9% v 12.5%; P < .01), despite the nearly identical mean burn size of the two groups. Except for burn incidence, there were no significant differences between males and females. The mean burn size was 15.1% +/- 0.7%, and was significantly larger for nonsurvivors than survivors (55.3% +/- 5.7 v 13.1% +/- 0.5%; P < .01). Inhalation injuries were strongly associated with large burns and were present in all 15 flame-burn fatalities. Scalds were the most common type of burn among children under 4 years of age; flame burns predominated in older children. There were 6 deaths related to scalds, all of which occurred in children under 4. Burn type, size, and mortality rate did not differ between children from urban and rural counties. Large burn size was the strongest predictor of mortality, followed by (in order) age less than 4 and the presence of inhalation injury. Infants and young children have the highest risk of death from burn injury. Burns smaller than 30% TBSA without an inhalation injury (such as small scald injuries) occasionally are lethal in infants and small children, despite modern therapy.

Effect of preoperative stabilization on respiratory system compliance and outcome in newborn infants with congenital diaphragmatic hernia.

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.

Emergency endotracheal intubation in pediatric trauma.

The purpose of this study was to determine the effectiveness and associated problems of emergency intubation in 605 injured infants and children admitted to the Childrens Hospital of Pittsburgh in 1987. We identified 63 patients (10.4%) undergoing endotracheal intubation at the scene of injury, at a referring hospital or in our emergency department. Injuries were to the head (90.5%), abdomen (12.7%), face (11.1%), chest (6.3%), neck (3.2%); or were orthopedic (19%) or multiple (39.7%). Indications for intubation included coma (74.6%), shock (28.6%), apnea (22.2%), and airway obstruction (3.2%). Of 16 complications (25.4%), 13 were immediately life threatening: right mainstem intubation (5), massive barotrauma (2), failure of adequate preoxygenation (2), esophageal intubation (1), attempt at nasotracheal intubation in an open facial fracture (1), and extubation during transport (1). Three were late complications: vocal cord paresis (2) and subglottic stenosis (1). Airway complications led to PO2 less than 90 mm Hg in 7 of 12 on first ABG, compared to 9 of 44 in uncomplicated cases (p less than 0.05). Intubation attempts at the scene of injury were more often multiple, unsuccessful, and associated with airway complications. All four complication-associated fatalities were life-threatening scene complications. Nearly one half (44.4%, 28 of 63) had one of the following problems in respiratory management: major airway complication, PaO2 less than 90, or PaCO2 greater than 45 on either the first or second ABG after arrival at our emergency department. Head injury with coma is the most common setting for emergency intubation. Airway complications are common, and are more frequent in treatment attempt at the scene. Despite endotracheal intubation, injured children in our series remain at high risk for hypoxemia, elevated arterial PCO2, and major airway complications, all of which contribute to secondary brain injury.

Reconstructive surgery for obstructing lesions of the intrathoracic trachea in infants and small children

This is a report of ten infants and small children with congenital obstructive lesions of the distal trachea and main bronchi. Four were successfully resected. One with a distal segment stenosis required tracheal resection at age 6 wk, another with stenosis of the distal half of the trachea at age 18 mo, and 2 (1 with distal stenosis and 1 with tracheal hamartoma) at age 4 yr. All 4 are presently free of symptoms and their anastomoses have grown without stricture. A child with coil-spring mucosal stenosis of the left main bronchus developed an excellent airway following bronchoscopic removal of the folds, and a baby with tracheomalacia was successfully treated with a rib splint on a segment of distal tracheomalacia, but she died later of associated cyanotic congenital heart disease. Four babies died with airway obstruction in the newborn period. Two with critical distal stenoses died before tracheal reconstruction could be performed. Two died following emergency resections in which all of the congenital stenosis could not be removed. In both, stenotic trachea remained despite operation. All of these infants had complete cartilage rings the entire length of the trachea. Congenital lesions of the distal trachea may become suddenly life-threatening at birth or during the onset of a respiratory infection. An abrupt or insidious onset of airway symptoms requires an expeditious diagnostic evaluation to define the tracheobronchial anatomy, and the operating team has to be prepared for emergency tracheal reconstruction.

Experimental pulmonary hypoplasia due to oligohydramios and its reversal by relieving thoracic compression

To investigate the role of thoracic compression in the etiology of pulmonary hypoplasia associated with oligohydramnios, we shunted amniotic fluid into the maternal abdominal cavity at 25-days gestation in one group of fetal rabbits and occluded the bladder outlet in another. Bladder-neck obstruction produced severe bilateral hydronephrosis. Both procedures produced oligohydramnios (amniotic fluid volume reduced, p less than .001) at reexploration on day 28. At term (day 31) newborns undergoing these procedures had significantly decreased lung weights (p less than .01). Lung histology was not affected. To determine whether decompression of the thorax would prevent pulmonary hypoplasia, another group of fetuses had their bladders occluded and underwent one of two procedures to relieve thoracic compression. In one group, amniotic fluid volume was restored by a constant infusion of normal saline. In the other, opening the abdomen and allowing viscera to herniate avoided thoracic compression from a diaphragm elevated by a dilated urinary tract and ascites. Liveborn obstructed rabbits undergoing either procedure had increased lung weight-to-body weight ratios compared to those in newborns undergoing only the obstructive procedure (p less than 0.05). These experiments suggest that mechanical restriction to lung growth plays a role in the development of pulmonary hypoplasia associated with oligohydramnios, and that pulmonary hypoplasia may be partially reversible by procedures which reduce thoracic compression.

Prenatal diagnosis and natural history of the fetus with a congenital diaphragmatic hernia: Initial clinical experience

To study the accuracy of prenatal diagnosis and define the natural history of fetal congenital diaphragmatic hernia (CDH), we reviewed experience with CDH at The University of California, San Francisco (UCSF) over the last three years. All nine babies born in our institution (inborns) and six of 11 babies referred from other hospitals after birth (outborns) died, an overall mortality of 75%. All had pulmonary hypoplasia. Forty percent had associated malformations or chromosomal abnormalities, a higher incidence than generally reported. Prenatal sonograms were available in all nine inborn cases. CDH was correctly diagnosed prospectively in only five, but could be recognized retrospectively in all nine cases using the sonographic criteria developed from the study. Polyhydramnios was present in all nine cases; in seven cases sonography was performed because the woman was large-for-dates clinically. There were no false positive interpretations, and when necessary the diagnosis was confirmed by amniography. All nine cases of CDH detected in utero died. Seven deteriorated so rapidly that surgical repair could not even be attempted. Two who had optimal care (maternal transport, immediate resuscitation and operation) died after repair despite maximal intensive care including vasodilator therapy. Despite the theoretical advantages of maternal transport to pediatric surgical specialty centers, a majority of fetuses with a prenatal diagnosis of CDH will die because their lungs are inadequate to support extra-uterine life even at term.