Pathogenesis and prevention of necrotizing enterocolitis: a hypothesis based on personal observation and a review of the literature.

The hypothesis is, that necrotizing enterocolitis (NEC) of the neonate occurs by the coincidence of two of three pathologic events: (1) intestinal ischemia, (2) colonization by pathogenic bacteria, and (3) excess protein substrate in the intestinal lumen. NEC is more likely to appear following quantitative extremes, ie, severe ischemia highly pathogenic flora, or marked excess of substrate. NEC develops only if a threshold of injury, sufficient to initiate intestinal necrosis, is exceeded. The hypothesis is derived from previous theories by Santulli, which implicated all three events, and by Lawrence, in which a single event, abnormal bacterial colonization, was considered sufficient to induce NEC. This hypothesis may explain both typical occurrences of NEC among high-risk premature infants in neonatal intensive care units (NICUs), and atypical occurrences among infants considered at low-risk, eg, previously healthy term infants, infants fed breast milk exclusively, and infants never fed. It may further explain why NEC fails to develop in most high-risk infants in NICUs. Preventive measures might include: (1) pharmacologic stabilization of intestinal perfusion, (2) modification of the intestinal flora, or (3) feeding colostrum or other protective substances. Each theoretical benefit is accompanied by potential risks. The prevention of NEC may require favorable intervention in two of the three pathologic events.

Management of tracheobronchial foreign bodies in children: a reevaluation of postural drainage and bronchoscopy.

The efficacy of the inhalation-postural drainage technique for removal of aspirated foreign bodies was compared with that of bronchoscopy in 76 children. Twelve of 49 children on postural drainage coughed out the foreign body (25%); the other 37 required bronchoscopy. The foreign body was successfully removed in 56 of 63 children who were bronchoscoped (89%). Our experience suggests that a trial of inhalation-postural drainage, administered in a hospital, may be valuable in the initial management of aspirated foreign bodies. If unsuccessful after several treatments, however, the technique should be abandoned, and bronchoscopy performed. Delay of foreign body removal beyond 24 hours may be associated with increased morbidity and prolonged hospital stay. With recent improvements in pediatric endoscopic instruments, the efficacy of bronchoscopy exceeds 90%.

The controversial role of decortication in the management of pediatric empyema.

Open surgical procedures for pleural empyema remain controversial in children. The pediatric literature generally recommends a prolonged trial of antibiotics and closed tube thoracostomy drainage. We report a favorable experience with a selective approach to open drainage in 22 children, many of whom had an empyema already organizing at admission. Open drainage was considered in children whose conditions failed to improve after 3 to 5 days of therapy with antibiotics and closed drainage. The method of drainage was selected according to the pathologic phase of the empyema: five children with fibrinopurulent empyema were successfully managed by limited decortication, and 17 with organizing empyema received decortication. Clinical improvement was usually dramatic; most of the children became afebrile by postoperative day 3 and were discharged by postoperative day 10. There were no deaths. Three children (14%) had complications of postoperative air leak or infection. Streptococcus pneumoniae (5) and Hemophilus influenzae (3) were the most common single pathogens. The presence of anaerobic bacteria in 8 of 22 children (36%) was associated with rapid organization of the empyema and the need for decortication. Decortication procedures have a low risk and are effective in children with empyema. They should be considered as definitive therapy, rather than as a last resort.

Cavitating primary pulmonary fibrosarcoma in a child.

Primary pulmonary sarcomas are rare tumors at all ages. They are usually solid and often remain silent until large. Prognosis is related to size and histologic characteristics. Curative efforts have been directed toward complete surgical removal. Presented in this report is an 11-year-old girl who was thought to have a bronchogenic cyst. At operation a 14 cm cavitating primary pulmonary fibrosarcoma was found, which was incompletely resected. The combined treatment modalities of surgical therapy and chemotherapy have resulted in a disease-free period of 36 months.

A reappraisal of the Mikulicz enterostomy in infants and children.

We performed the Mikulicz procedure in 46 pediatric patients. Thirty-five were high-risk patients, 20 of whom had necrotizing enterocolitis. High risk was defined by the presence of peritonitis, intestinal perforation, poorly demarcated intestinal gangrene, or severe associated systemic illness. The remaining 11 patients had the procedure performed for technical reasons, most commonly a discrepancy in the size of the proximal distal limb ratio greater than 4:1. The procedure consisted of intestinal resection with double-barreled enterostomy, crushing of the spur between stomas, and subsequent lateral closure of the enterostomy. The mortality rate of 30% was due to the underlying disease and in no instance was death caused by a complication of the procedure. Complications (13%) were stricture or prolapse of the stoma and wound infection. Subsequent enterostomy closure in 32 patients had no mortality rate and a 3% complication rate. Because the risk of fatal anastomotic leak and peritonitis is very low, we prefer the Mikulicz procedure to all other intestinal anastomotic techniques for high-risk pediatric patients.

Indications for operation in acute necrotizing enterocolitis of the neonate.

A study to evaluate criteria for operation was carried out in 61 infants with acute necrotizing enterocolitis (NEC). A total of 10 clinical, roentgenographic, and laboratory criteria were considered. Each proposed operative criterion was correlated with the documented presence or absence of intestinal gangrene in these infants. Indications for operation verified by this study were (1) pneumoperitoneum, (2) paracentesis findings positive for gangrenous intestine, (3) erythema of the abdominal wall, (4) a fixed abdominal mass, and (5) a persistently dilated loop of intestine on serial abdominal radiographs. The first two signs occurred frequently; the latter three were rare. Operative indications which proved to be invalid in this study were (1) clinical deterioration, (2) persistent abdominal tenderness, (3) profuse lower gastrointestinal hemorrhage, (4) the roentgenographic finding of gasless abdomen with ascites, and (5) severe thrombocytopenia. Twenty-four of the infants were operated on. The mortality rate among the infants operated on after free intestinal perforation had occurred (64%) was double that of infants operated on for intestinal gangrene without perforation (30%). Paracentesis may identify infants with intestinal gangrene prior to the development of perforation and may permit advantagenous timing of operation. This analysis of the frequency and reliability of proposed operative criteria may aid the surgical decision.

Paracentesis as an aid to the diagnosis of intestinal gangrene: experience in 50 infants and children.

We performed paracentesis or peritoneal lavage on 50 seriously ill infants and children in whom the diagnosis of intestinal gangrene or perforation was suspected. Thirty-four infants had necrotizing enterocolitis and 16 had other conditions. In infants with suspected intestinal gangrene, the presence of brown peritoneal fluid and/or bacteria on Gram's stain was indicative of intestinal gangrene. In infants with pneumoperitoneum, the presence of cloudy fluid with leukocytosis was indicative of gastrointestinal perforation. Using these two criteria, the accuracy of paracentesis in predicting the need for operation was 90%. When combined with clinical judgment, the accuracy rose to 97.5%. The rate of negative findings from abdominal explorations was 5%. Analysis of the peritoneal fluid may improve the timing and accuracy of the operative decision.

Necrotizing enterocolitis of the neonate.

Necrotizing enterocolitis is the most common gastrointestinal emergency in the newborn. The syndrome strikes premature infants during the first 2 weeks of life. Abdominal distention, lethargy, and feeding intolerance are early signs of NEC that may progress to gastrointestinal bleeding and hemodynamic instability. The radiographic hallmark of NEC is pneumatosis intestinalis (air in the bowel wall). The ileum and colon are the usual sites of crepitant intestinal necrosis, leading frequently to perforation. In spite of appropriate medical therapy, about half of the infants with NEC develop intestinal gangrene or perforation and require surgery, consisting of bowel resection and enterostomy formation. The most common late complication, intestinal stricture, occurs in 15 to 35 per cent of recovered infants. Overall mortality from NEC ranges from 20 to 40 per cent. The etiology of NEC is poorly understood and is considered to be multifactorial, related to ischemia, bacterial colonization, and formula feedings in a susceptible infant. Future progress in the treatment of NEC may be achieved by earlier detection of necrosis, modification of gastrointestinal flora, or by bolstering the deficient gastrointestinal immune mechanisms of the premature neonate.

Left mainstem bronchopexy for severe bronchomalacia.

Severe bronchomalacia occurred in a 14-month-old boy, as a result of compression of the left mainstem bronchus by a bronchogenic cyst. After resection of the cyst, the bronchomalacia was corrected by suspension of the posterolateral bronchial wall to the ligamentum arteriosum. This method of bronchopexy may be of value for severe left mainstem bronchomalacia.

Indications for operation in necrotizing enterocolitis revisited.

Operation for necrotizing enterocolitis (NEC) is reserved for infants with intestinal gangrene or perforation. It should not be undertaken until gangrene is present, but ideally should be performed before intestinal perforation occurs. To characterize the onset of intestinal gangrene, data were analyzed for 147 infants with documented NEC, 94 of whom had gangrene. Twelve criteria were evaluated as predictors of intestinal gangrene, using standard epidemiological measures for diagnostic tests. Sensitivity, specificity, positive predictive value, negative predictive value, and prevalence were calculated for each of the proposed operative criteria. The best indications were those whose specificity and positive predictive value approached 100%, and whose prevalence was greater than 10%. These were pneumoperitoneum, positive paracentesis, and portal venous gas. Good indications were those whose specificity and positive predictive value approached 100%, but whose prevalence was less than 10%. These were fixed intestinal loop noted on x-ray, erythema of the abdominal wall, and a palpable abdominal mass. A fair indication for operation--with 91% specificity, 94% positive predictive value, and prevalence of 20%--was "severe" pneumatosis intestinalis, graded by a radiographic system. Poorer indications for operation (and their predictive value for the presence of gangrene) were clinical deterioration (78%), platelet count below 100,000/mm3 (73%), abdominal tenderness (58%), severe gastrointestinal hemorrhage (50%), and gasless abdomen with ascites (0%). No test had a high sensitivity for intestinal gangrene. Portal venous gas should be acknowledged as an indication for operation. Probability analysis may provide a more scientific basis for clinical decision-making.

Azygous flap technique for reinforcement of esophageal closure.

A tissue flap of azygous vein was successfully used for reinforcement of the esophageal anastomosis in two infants with wide-gap esophageal atresia and carinal tracheoesophageal fistula. In spite of anastomotic tension, both esophagi healed without leak or stricture. This technique may be of value in the surgical correction of esophageal anomalies.

Debridement of periumbilical necrotizing fasciitis: importance of excision of the umbilical vessels and urachal remnant.

The operation of a neonate with periumbilical necrotizing fasciitis consisted of (1) excision of infected skin, fat, and fascia (including the umbilicus); (2) a limited laparotomy, with ligation and excision of the umbilical vessels and urachal remnant; and (3) placement of a temporary silastic patch over the central abdominal defect. Pathological sections confirmed the spread of infection along the vessels and urachal remnant. Excision of the vessels and urachal remnant may be crucial to survival from periumbilical necrotizing fasciitis.

A bacteriologic basis for the clinical presentations of necrotizing enterocolitis.

A study to identify putative bacterial pathogens in infants with necrotizing enterocolitis (NEC) was begun in 1976. Cultures of blood and of peritoneal fluid obtained by paracentesis were carried out in 25 infants with NEC. Segments of intestine excised at operation were Gram stained. Of the 25 infants, 8 recovered with medical management and 17 required operations. The 8 medically treated infants had sterile peritoneal fluid and, with 2 exceptions, sterile blood cultures. Of the 17 operated infants, 16 had bacteria in their blood and/or peritoneal fluid. The majority of resected bowel specimens from these infants contained a confirmatory morphologic type of bacterium within the wall. The clinical course of 8 infants with clostridia was compared to that of 8 infants with gram-negative enteric bacteria (Klebsiella, E. coli, or Bacteroides fragilis). The infants with clostridia were sicker. They had more extensive pneumatosis intestinalis, a higher incidence of portal venous gas, more rapid progression to gangrene, and more extensive gangrene. Infants with gram-negative rods had lower birth weights and lower platelet counts than the clostridial group. The difference in mortality between the two groups was not significant. The inherent pathogenicity of the gut flora may influence the clinical course of NEC. Among infants who develop intestinal gangrene, the clostridia appear to be more virulent than gram-negative enteric bacteria.

Prediction and prevention of anastomotic complications of esophageal atresia and tracheoesophageal fistula.

We analyzed our experience with 64 infants with esophageal atresia (EA) and tracheoesophageal fistula (TEF), to determine the possibility of prediction and prevention of anastomotic complications (leak, stricture, and recurrent TEF). In most of the infants, the anatomical level of the fistula was documented preoperatively by bronchoscopy. The level of the fistula, in turn, correlated with the esophageal anatomy at thoracotomy, ie, carinal fistulas had a wide gap between esophageal pouches, whereas midtracheal or cervical fistulas had a minimal gap. Major anastomotic complications were defined as leak requiring reoperation, symptomatic strictures requiring four or more dilatations, or a recurrent TEF. The complication rates wre: leak (major and minor), 21%; major stricture, 15%; and recurrent TEF, 5%. Major complications occurred in 42% (11/26) of infants with wide gaps, compared with 8% (3/36) of infants with minimal gaps. Route of repair (transpleural or retropleural) made no difference in incidence of anastomotic complications. No infant died of an anastomotic complication. Survival was 100% for Waterston A and B infants, 83% for Waterston C, and 90% overall. Severe gastroesophageal reflux, requiring Nissen fundoplication, was more common among infants with wide gaps than those with minimal gaps (32% v 3%). The most important pathogenetic factor, present in 79% (11/14) of major anastomotic complications, was anastomotic tension, determined by the gap between esophageal pouches, and predicted by preoperative bronchoscopy. Thus the bronchoscopic finding of a carinal fistula signals the need for technical measures that may limit anastomotic morbidity, such as myotomy, patching the anastomosis, retropleural approach, or delayed repair. Assuming precise technique and gentle handling of tissues, the anatomy of the anomaly determines the anastomotic morbidity of EA and TEF.

An expandable prosthesis for stabilization of the infant mediastinum following pneumonectomy.

One possible complication in infant pneumonectomy is mediastinal shift that can fatally kink or compress airways and vessels. Rigid prostheses have been used to prevent these problems; however, they cannot be adjusted as the child grows. We report a case of expandable prosthesis implantation in a 24-day-old infant. During the 18 months postimplantation, the prosthesis was periodically injected with a saline/contrast solution to maintain the mediastinum in a midline position as the child grew. At 24-month follow-up the prosthesis was still in place, and midline position of the mediastinum maintained.

Pneumonostomy in the management of pediatric lung abscess.

Emergency pneumonostomy was curative in a critically ill child with acute lung abscess. This procedure may be indicated for the rare acute lung abscess which fails to respond to medical therapy.

Paracentesis and lavage for diagnosis of intestinal gangrene in neonatal necrotizing enterocolitis.

A study to evaluate peritoneal fluid as an index of intestinal gangrene in infants with necrotizing entercolitis (NEC) was begun in 1974. Twenty samples of peritoneal fluid were obtained by paracentesis or lavage from 15 infants with nonperforated NEC. A brown color in the peritoneal fluid was noted in all 8 patients found to have intestinal gangrene at subsequent operation. Gram stain showed bacteria in 6 of these 8 patients and bacterial cultures were confimatory in all but one. In 12 samples of peritoneal fluid in patients without intestinal gangrene, the fluid was straw-colored or pink and Gram stain showed no bacteria. The decision to operate on an infant with intestinal gangrene and impending perforation may be aided by analysis of the peritoneal fluid.

A technique for preservation of the ileocecal valve in the neonatal short intestine.

We report a technique, appendiceal interposition, which permitted preservation of the ileocecal valve in an infant with a congenitally short intestine (jejunum, 12 cm; ileum, 1 cm). The procedure was performed on the first day of life in conjunction with jejunal lengthening by the Bianchi technique. The result was a small intestine of 21 cm in length with an intact ileocecal valve.

Postoperative wound infection in pediatric surgical patients: a study of 676 infants and children.

We conducted an epidemiologic study of postoperative wound infection in pediatric patients. Over a 14-month period, 676 patients who received an operative incision on the Pediatric Surgical service were entered. Demographic, nutritional, clinical, and laboratory data were collected. The patients were followed for development of postoperative wound infection. Cultures were taken from wounds to identify the offending organisms. Of the 676 patients, 137 were neonates, 197 infants, and 342 older children. Wound infection occurred in 17 patients (2.5%): 1 neonate (0.7%), 8 infants (4.1%), and 8 older children (2.3%). Infection rates according to wound classification were: clean 1.0%, clean-contaminated 2.9%, contaminated 7.9%, and dirty 6.3%. Heavily contaminated or dirty wounds were packed open in one third of cases, and allowed to heal by granulation. The largest group of wound infections followed operations on the gastrointestinal tract (10 patients, 267 operations, 3.7%). Staphylococcus aureus, Escherichia coli, and alpha hemolytic streptococcus were the most common wound pathogens. An increased rate of wound infection was associated with operative procedures longer than 1 hour, with the presence of an associated illness, and with emergency operations. Age, sex, nutritional status, and duration of preoperative hospital stay did not significantly alter the wound infection rate. It could be concluded that the incidence of wound infection was lower among pediatric surgical patients than the reported incidence in adult surgical patients. The greatest risk factors were those associated with local contamination of the surgical wound.

Nosocomial infection in pediatric surgical patients: a study of 608 infants and children.

We studied nosocomial infection in a group of 608 pediatric surgical patients over a 14-month period. All inpatients and outpatients who received an operation with an incision by the pediatric general surgical service were entered into the study. Demographic, nutritional, clinical, and laboratory data were collected. Surveillance was conducted for wound infection, septicemia, infections of the respiratory tract, urinary tract, and abdomen, and infectious diarrhea. A total of 676 operative procedures was performed. Nosocomial infection occurred in 38 of the 608 patients (6.2%). A total of 53 infectious complications was tabulated. The number and percent risk per operation were wound 17 (2.5%), septicemia 14 (2.1%), pulmonary 10 (1.5%), urinary tract 5 (0.7%), abdominal 5 (0.7%), diarrhea 2 (0.3%). Broviac catheter sepsis occurred in 7 of 61 lines (11.5%). The highest overall occurrence of infection was in the infant group (1 mo to 1 yr), (13/161, 8.1%). The probability of septicemia was highest in neonates (4.2%) compared with infants (3.1%) or older children (1.2%) (P < .05). The most common isolates were Staphylococcus epidermidis (10/17) from septic patients, and gram-negative enteric bacteria (27/50) from organ and wound infections. Infection was associated with impaired nutrition, multiple disease processes, and multiple operations. The risk of nosocomial infection in this population was comparable to that reported in adult surgical patients. These baseline data may aid the development of strategies to lower infection risk in children.