Pathophysiology of ovine smoke inhalation injury treated with extracorporeal membrane oxygenation.

An ovine model was used to study the pathophysiology of smoke inhalation injury treated with extracorporeal membrane oxygenation (ECMO). Smoke inhalation is characterized by leukocyte-oxygen free-radical mediated acute lung injury. Treatment with ECMO was by extracorporeal venoarterial or venovenous perfusion using a venous drainage reservoir, roller pump, heat exchanger, and membrane lung oxygenator capable of oxygen delivery to and carbon dioxide removal from a patient. Blood-foreign surface interactions are known to occur during ECMO. We examined the effects of ECMO on circulating leukocytes, oxygen free-radical activity, thromboxane release, and gas exchange after smoke inhalation injury. Animals treated with smoke and ECMO had significantly increased circulating thromboxane B2 levels and oxygen free-radical activity compared with sham-treated animals and animals treated with smoke and mechanical ventilation (MV). Likewise, there was a significant increase in lung wet-to-dry weight ratios in animals treated with smoke and ECMO compared with those treated with smoke and MV. These data may account for the initial deterioration in native lung function after the initiation of ECMO and imply that ECMO may potentiate the pathophysiology of smoke inhalation injury.

Coumarin necrosis--a review of the literature.

Skin and soft tissue necrosis is a rare complication of anticoagulation therapy. Two patients who exhibited the spectrum of this disorder are described. The clinical features, etiology, pathophysiology, and treatment of coumarin skin necrosis are outlined, and the English-language literature is reviewed.

Right lower quadrant pain in children caused by omental infarction.

BACKGROUND: Omental infarction is a rare cause of abdominal pain, with fewer than 300 cases reported in the literature. Only 15% of reported cases occur in the pediatric population. We present our experience with 18 children diagnosed with omental infarction admitted to Texas Children's Hospital over a 15-year period. STUDY DESIGN: A retrospective review of clinical records, diagnostic images, and pathologic findings was carried out for all children diagnosed with isolated omental infarction from 1986 to 2000 in order to analyze presenting signs and symptoms, preoperative imaging, surgical management, and postoperative outcomes. RESULTS: Eighteen children were treated for isolated omental infarction. There were 12 boys and 6 girls with an average age of 7.5 years (range 2 to 13). All patients presented with acute onset of right lower quadrant pain. Only 5 of 18 (24%) had associated gastrointestinal symptoms. The average temperature at presentation was 99.4 degrees F (+/- 0.78). The average white blood cell count was 11.4 (+/- 4.4). Fourteen patients had ultrasonographys performed preoperatively: 6 of 14 incorrectly diagnosed appendicitis, 4 of 14 were nondiagnostic and 4 of 14 correctly diagnosed omental infarction. Two of 18 patients underwent computed tomography scans, which were diagnostic for omental infarction. Resection of the infarcted omentum was performed in all patients and appendectomy in 16 of 18. Thirteen patients underwent an open procedure, 5 were performed laparoscopically. There were no postoperative complications. All patients had resolution of pain postoperatively and were discharged an average of 3.0 (+/- 0.9) days after admission. CONCLUSIONS: Omental infarction is an uncommon cause of right lower quadrant pain in children and is often diagnosed as appendicitis preoperatively. Ultrasonography and computed tomography can be diagnostic. Surgical resection of the infarcted omentum results in immediate resolution of pain with no morbidity.

Ostomy closure for recurrent stomal hemorrhage: an indication for prophylactic sclerotherapy in biliary atresia.

Two patients with failed drainage procedures for biliary atresia are presented in whom major hemorrhage from esophageal varices followed shortly after ostomy closure for recurrent stomal bleeding. Before ostomy closure is contemplated in these patients, evaluation for esophageal varices and their prophylactic obliteration with sclerotherapy is recommended.

Subcutaneous palisading granulomas (benign rheumatoid nodules) in children.

Subcutaneous palisading granulomas (SPG), also known as benign rheumatoid nodules, occur in otherwise healthy children. Although these lesions have the same histology as rheumatoid nodules in adults, subcutaneous granuloma annulare, and diabetic lipoidicum, they appear to represent a distinct clinicopathologic entity. We reviewed our experience with 17 cases of SPG. All patients presented with one or more painless, nonmobile, subcutaneous nodules. Lower extremity involvement was most common, but lesions presented in the upper extremities and scalp as well. There were 14 girls and three boys ranging in age from 10 months to 15 2/12 years (mean, 4 5/12 years) at the time of diagnosis. Past medical histories were negative. Laboratory and radiologic studies were normal except for one child with an elevated erythrocyte sedimentation rate (ESR). The follow-up period ranged from 6 months to 14 10/12 years (mean, 4 11/12 years). Subsequent new lesions developed in nearly two thirds of the patients. In the one child with an initially elevated ESR, rheumatoid arthritis developed. All others were alive and well except for one who died in a motor vehicle accident without evidence of further disease. Preoperative diagnosis was correct in only three patients. Excisional biopsy was performed in all cases. However, one child had received prior radiation therapy, one received topical steroid therapy, and three patients had subsequent lesions excised. All subsequent lesions not surgically excised underwent spontaneous involution.(ABSTRACT TRUNCATED AT 250 WORDS)

Decreasing blood donor exposure in neonates on extracorporeal membrane oxygenation.

Extracorporeal membrane oxygenation (ECMO) has been successful treatment (80% survival) in over 2,000 neonates with severe respiratory failure (80% predicted mortality without ECMO). Neonates on ECMO require frequent blood product replacement, which increases donor exposure (DE) and the risk of transfusion related complications. Successful, widespread usage of ECMO in neonatal respiratory failure is placing increased numbers of surviving infants at risk for acute and long-term transfusion related problems. We assessed DE rates in 21 consecutive neonatal ECMO survivors. In the first 12 patients packed red blood cell (PRBC) transfusions were administered as 10 mL/kg body weight for hematocrit less than 45%. PRBC exchange transfusions were used in patients with hematocrit less than 45% and hypervolemia. Fresh frozen plasma (FFP) and cryoprecipitate (CRYO) infusions were used empirically for evidence of hemorrhage. DE rates (donors per ECMO day, mean +/- SD) were: PRBC (2.8 +/- 0.6), FFP/CRYO (0.5 +/- 0.7), and platelet (2.0 +/- 1.0), with a total donor exposure rate of 5.3 +/- 2.0 donors per ECMO day. Mean duration of ECMO was 4.6 +/- 2.0 days and total DE per infant was 22.8 +/- 9.5 donors per ECMO run. In a protocol (n = 9) to minimize DE risks, exchange transfusions were eliminated and PRBC transfusion volumes were increased to 15 mL/kg. Empiric use of FFP and CRYO was discontinued. The blood bank divided standard units of PRBCs into four aliquots and dispensed each aliquot sequentially before dispensing blood from another unit.(ABSTRACT TRUNCATED AT 250 WORDS)

Improved myocardial oxygen utilization following propranolol infusion in adolescents with postburn hypermetabolism.

The purpose of this study was to determine if propranolol (0.5 mg/kg and 1 mg/kg), administered intravenously (IV) at the height of the postburn hypermetabolic response, would decrease myocardial oxygen requirements, without adversely affecting overall oxygen delivery or total body oxygen consumption. To test this hypothesis, six nonseptic patients age 17 +/- 3 years with burns over 82% +/- 11% total body surface area were given propranolol with continuous hemodynamic monitoring. Propranolol was administered to these patients 20 +/- 15 days postburn. Two clinically derived indices of myocardial oxygen consumption, pressure-work index (PWI) and rate-pressure product (RPP), were used to estimate the energy expenditure of the working heart. Both PWI and RPP were significantly decreased from baseline after 0.5 mg/kg propranolol, 31% for PWI (P less than .001) and 30% for RPP (P less than .01). Similarly, a decrease from baseline was seen after 1.0 mg/kg propranolol, 32% for PWI (P less than .001) and 35% for RPP (P less than .01). Cardiac index (L/min/m2) demonstrated no significant change [7.4 +/- 1.1 (prepropranolol), 6.5 +/- 1.3 (after 0.5 mg/kg propranolol), and 6.8 +/- 1.0 (after 1.0 mg/kg propranolol)] and exceeded the upper limits of normal (hyperdynamic state) throughout the study. Oxygen delivery index (962 +/- 209 mL/min/m2) and oxygen consumption indices [(254 +/- 78 mL/min/m2 by Fick method and 236 +/- 78 mL/min/m2 by inspired and expired gases)] were elevated at baseline and unaffected by propranolol. The decrease in PWI and RPP was achieved mainly by propranolol's effect to lower both heart rate and BP.(ABSTRACT TRUNCATED AT 250 WORDS)

Neurodevelopmental outcome in neonates after extracorporeal membrane oxygenation: cranial magnetic resonance imaging and ultrasonography correlation.

Irreversible ligation of the right common carotid artery and right internal jugular vein is usual in venoarterial extracorporeal membrane oxygenation (ECMO) for treatment of severe respiratory failure in neonates. Vessel ligation with ECMO may magnify risks of cerebral hemorrhage or infarction (CHI) and adversely affect neurodevelopmental outcome. To correlate CHI after ECMO with neurodevelopmental outcome, we reviewed cranial ultrasonography (US) and magnetic resonance imaging (MRI) scans in 22 consecutive neonatal ECMO survivors and compared these with results of Bayley Scales of Infant Development obtained at 3, 6, 12, and 24 months of follow-up. All patients had US, and 19 had MRI. No US or MRI had focal abnormal findings attributable to ECMO; specifically, there was no evidence of CHI. Two infants had generalized cerebral atrophy, and one of these had an abnormal Bayley examination. One infant with a normal MRI had a single right focal seizure 4 days after ECMO. Of 20 infants with Bayley developmental tests at 3 to 30 months of age (mental index range, 72 to 135; motor index range, 71 to 150), only 3 were abnormal. In our experience, the incidence of CHI secondary to ECMO is less than that reported. After ECMO, the absence of intracranial hemorrhage, cerebral infarct, or cerebral atrophy on US or MRI usually correlates with normal short-term neurodevelopmental outcome.

Peritoneal drainage as definitive treatment for neonates with isolated intestinal perforation.

BACKGROUND/PURPOSE: To better define the indications for peritoneal drainage (PD) in premature babies with intestinal perforation, the authors reviewed their experience with this procedure in a tertiary neonatal intensive care setting. METHODS: The charts of all neonates who underwent PD as initial treatment for intestinal perforation between 1996 and 1999 were reviewed. Those patients with pneumatosis intestinalis on abdominal radiograph had perforated necrotizing enterocolitis (NEC) diagnosed; whereas, those infants with no pneumatosis had isolated intestinal perforation diagnosed. The clinical characteristics and outcomes of these 2 groups were compared. RESULTS: Twenty-one premature neonates had primary PD between 1996 and 1999, 10 for isolated intestinal perforation and 11 for perforated NEC. Patients with isolated intestinal perforation had lower birth weights (708 v 949 g; P < .05), were less likely to have started feedings (30% v 91%, P < .05), and the perforation developed at an earlier age (10.6 v 28.0 d, P < .05) compared with the patients who had perforated NEC. Only 2 of 10 infants with isolated perforation required subsequent laparotomy (at 10 weeks for stricture and 12 weeks for a persistent fistula). For these patients, the long-term survival rate was 90%. In contrast, 8 of 11 infants with perforated NEC required laparotomy, and although the 30-day survival rate was 64%, the long-term survival rate was only 27%. CONCLUSIONS: Peritoneal drainage provides successful and definitive treatment for most premature babies with isolated intestinal perforation. For neonates with perforation caused by NEC, peritoneal drainage may provide temporary stabilization, but most of these infants require subsequent laparotomy, and few survive.

Surgery for ovarian masses in infants, children, and adolescents: 102 consecutive patients treated in a 15-year period.

BACKGROUND/PURPOSE: Ovarian pathology, although rare in children, must be included in the differential diagnosis of all girls who present with abdominal pain, an abdominal mass, or precocious puberty. METHODS: To improve clinical appreciation of these lesions, the authors reviewed the presentation, evaluation, and outcome of all patients with ovarian pathology surgically treated at their institution since 1985. RESULTS: One hundred two girls (aged 9.8 +/- 5.5 years; range, 2 days to 20 years) underwent 106 separate ovarian operations (43 salpingo-oophorectomies, 21 oophorectomies, 33 ovarian cystectomies, and 9 ovarian biopsies). Of those presenting with acute abdominal pain (n = 59), 25 (42%) had ovarian torsion (14 associated with a mature teratoma), and only 1 (2%) had a malignant tumor. In contrast, of those presenting with an abdominal mass (n = 23), 6 (26%) had malignancies. There was no age difference between those with benign disease (9.9 +/- 5.6 years; n = 96) and those with malignant tumors (8.6 +/- 3.9 years, n = 10). Nine children had 10 operations for presumed malignant tumors (3 dysgerminomas, 2 immature teratomas with foci of yolk sac tumor, 2 juvenile granulosa cell tumors, 1 yolk sac tumor, and 1 Sertoli-Leydig cell tumor). These patients all had unilateral salpingo-oophorectomy, 4 had chemotherapy, and all are now disease free at 8.4 +/- 4.1 years follow-up. CONCLUSION: Ovarian pathology remains a rare indication for surgery in girls less than 20 years of age. Because most of these lesions are benign, ovarian-preserving operations should be performed whenever feasible.

Benefits of a lower hematocrit during extracorporeal membrane oxygenation?

OBJECTIVE: To determine the possible benefits of maintaining a lower hematocrit than that normally used (0.35 vs 0.45) in neonates treated with extracorporeal membrane oxygenation. DESIGN: Randomized cohort. SETTING: Neonatal and pediatric intensive care units at a university hospital. PARTICIPANTS: Twenty neonates who met criteria for receiving extracorporeal membrane oxygenation from May 1988 to March 1990. INTERVENTIONS: Hematocrits were maintained at 0.35 for neonates in group 1 and 0.45 for neonates in group 2. MEASUREMENTS/MAIN RESULTS: Hematocrits were measured every 4 hours. Visible clots in the major circuit components were recorded. Infants in group 1 received (mean +/- SD) 2.5 +/- 0.6 mL of packed red blood cells per hour of extracorporeal membrane oxygenation while infants in group 2 received 3.8 +/- 0.9 mL of packed red blood cells per hour of extracorporeal membrane oxygenation. In group 1, clots were noted in six of 10 oxygenators and five of 10 bladder reservoirs. In group 2, clots were found in all 10 oxygenators and bladder reservoirs. CONCLUSIONS: Neonates' hematocrits can be maintained safely at 0.35 during extracorporeal membrane oxygenation with significantly less exposure to packed red blood cells and less clotting in the circuit.

Extracorporeal membrane oxygenation for gram-negative septic shock in the immature pig.

Extracorporeal membrane oxygenation (ECMO) can provide total cardiopulmonary support via extrathoracic vascular cannulation. We evaluated the effects of ECMO in gram-negative septic shock in immature piglets subjected to fecal-Escherichia coli peritonitis. Group I, SEPSIS CONTROL (n = 10), had an intraperitoneal injection of E. coli but did not receive ECMO. Group II, ECMO CONTROL (n = 5), had 24 hr of ECMO support without the intraperitoneal injection of E. coli, and Group III, ECMO SEPSIS (n = 4), had an intraperitoneal injection of E. coli and was treated with ECMO. In the SEPSIS CONTROL group, mean survival time (+/- SD) was 13.8 +/- 6.3 hr with two survivors to 24 hr. In the ECMO CONTROL group, all five animals survived 24 hr on ECMO and then weaned successfully to conventional ventilatory therapy with return of spontaneous circulation. In the ECMO SEPSIS group, one of the animals died after 22 hr on ECMO and the other three animals died at 24 hr immediately upon withdrawal of ECMO support. Conventional ventilatory therapy was unsuccessful in each. Systemic arterial blood pressure was significantly higher in ECMO CONTROL animals (P less than 0.01) as were leukocyte counts (P less than 0.01). In this model of gram-negative septic shock, ECMO did provide cardiopulmonary support but did not improve mortality.

Intraabdominal desmoplastic small round cell tumor presenting as a gastric mural mass with hepatic metastases.

PURPOSE: An atypical case of childhood intraabdominal desmoplastic small round cell tumor (DSRCT) is presented. PATIENT AND METHODS: An 11-year-old boy presented with progressive nausea and vomiting, abdominal pain, hepatomegaly, and an epigastric mass. Computed tomographic scanning as well as findings at gastroscopy and laparotomy revealed a large gastric mural tumor accompanied by multiple large intrahepatic masses. Histopathologic examination of biopsy samples revealed evidence of a polyphenotypic neoplasm diagnostic of DSRCT. RESULTS: Unlike most reported cases of DSRCT, no evidence of peritoneal involvement or ascites was detected. Despite an excellent initial response to multiagent chemotherapy, the patient eventually died of progressive tumor. CONCLUSIONS: Though the radiographic and surgical findings in DSRCT usually suggest a mesenteric, peritoneal, or retroperitoneal site of tumor origin, this case demonstrates that intraabdominal DSRCT can present with a primary visceral lesion without evidence of peritoneal or mesenteric involvement or ascites. Combination chemotherapy using vincristine, doxorubicin, cyclophosphamide, cisplatin, and 5-fluorouracil may be of some benefit to patients with this rare tumor.

Immediate positive pressure ventilation with positive end-expiratory pressure (PEEP) improves survival in ovine smoke inhalation injury.

BACKGROUND: The purpose of this study was to compare the effects of immediate initiation of positive pressure ventilation (PPV) with positive end-expiratory pressure (PEEP) versus the initiation of PPV with PEEP only after hypoxemia ensued following severe smoke inhalation injury. METHODS: We prospectively evaluated chronically instrumented adult sheep treated with immediate versus delayed PPV with PEEP and compared oxygen requirements, hemodynamics, pleural fluid formation, postinjury survival, and tracheobronchial pathologic processes among groups. The immediate group (group I; smoke, n = 6; sham, n = 2) underwent tracheostomy and bilateral chest tube placement before they received inhalation injury. They were then immediately placed on PPV with PEEP (12 cm H2O). The animals in the delayed group (group D) (n = 6) were placed on PPV with PEEP when arterial hypoxemia (PaO2 < 80 mm Hg [11.2 kPa] on 0.4 FIO2) or respiratory distress developed. RESULTS: Groups were matched for smoke exposure and peak carboxyhemoglobin. Both groups developed a characteristic decrease in PaO2/FIO2 ratio. Initiation of PPV + PEEP improved PaO2 in the delayed group (69 +/- 7 to 126 +/- 21 mm Hg [9.2 +/- 0.9 to 16.7 +/- 2.8 kPa]). Pleural fluid output was greater in the immediate group compared with the delayed group (1559 +/- 415 vs. 426 +/- 236 mL). At 96 hours after injury five of six animals in the delayed group had died. In contrast, six of six animals in the immediate smoke group survived 96 hours (p < 0.05 versus delayed group). The immediate group had fewer and less extensive tracheobronchial casts at necropsy. CONCLUSIONS: Immediate PPV + PEEP did not prevent the development of hypoxia and was associated with increased pleural fluid formation. Death within 96 hours in the delayed group was the result of respiratory failure aggravated by bronchial cast formation despite vigorous pulmonary toilet. Early positive pressure ventilation with PEEP, preferably initiated immediately after the inhalation insult, significantly increases short-term survival and is associated with decreased tracheobronchial cast formation in this ovine model of severe smoke inhalation injury.