Diaphragmatic pacing in children with congenital central alveolar hypoventilation syndrome.

BACKGROUND: The purposes of this study were to study congenital central alveolar hypoventilation syndrome (CCAHS), to report the experience at our institution with this disorder, and to describe the surgical technique of diaphragmatic pacing. Three patients are in our diaphragmatic pacing program. They all have CCAHS, documented by means of lack of respiratory drive to hypercapnia and normal peripheral nerve and muscle studies. Two patients have associated Hirschsprung's disease. METHODS: The ages of patients at insertion of bilateral phrenic nerve pacemakers were 1, 2, and 5 years. A bilateral axillary thoracotomy in the third interspace was used in two patients, and anterior thoracotomy was used in one for insertion of electrodes on the phrenic nerves. Counterincisions in both flanks were used in all patients for insertion of the receivers in subcutaneous pockets. RESULTS: In all patients pacing was commenced within 1 week of the surgical procedure, because no primary pacemaker failures occurred. One patient has experienced no failure of the equipment and no infectious complications at 4 years. A second patient has had the pacemakers for 6 months without complications. The third patient underwent placement of bilateral pacemakers in 1984. In this patient a 10-year experience has resulted in subcutaneous implant failure on two separate occasions; also the presence of a staphylococcal empyema necessitated the temporary removal of one phrenic nerve electrode for 6 months, with successful reinsertion. All patients now receive mechanical assisted ventilation when sleeping and phrenic nerve pacing when awake. CONCLUSIONS: Pediatric surgeons should be aware of CCAHS because it may be treated with surgically implanted electrodes that allow for pacing of the diaphragm. The technique has an acceptable complication rate, and it can greatly decrease the impact of the disease on the lifestyle and activity of the patient. CCAHS also may be associated with Hirschsprung's disease.

Uses of extracorporeal membrane oxygenation in nonneonatal respiratory patients. An update.

Neonatal extracorporeal membrane oxygenation (ECMO) has progressed rapidly from the experimental stage to a standard of care for certain infants who fail to respond to maximal conventional management. A broad diagnostic group of nonneonatal patients has now been supported by several different modes of ECMO with encouraging results. Selection criteria for nonneonatal patients that differ from those used for neonatal patients are emerging. Prospective randomized clinical trials are needed.

Fetal tissue repair and wound healing.

The fibrosis and scar formation that characterize adult wound healing are also the cause of clinical problems; scar contracture, hypertrophic scar, and pulmonary and hepatic fibrosis are only a few examples. Studies of fetal wound healing can provide an insight into the initiation and regulation of a scarless repair process akin to regeneration. Studies of fetal repair have already suggested mechanisms that might favorably alter adult healing. Topical application of hyaluronic acid to wounds in adult diabetic rats leads to enhanced epithelial migration. It has been recognized that the addition of TGF-beta to fetal wounds causes an adultlike healing response with fibrosis and inflammation. A subsequent study using neutralizing antibody to TGF-beta in adult wounds showed enhanced healing with a more normal dermal architecture with fewer macrophages, fewer blood vessels, and less collagen. As our understanding of regenerative tissue repair increases, the opportunities to modulate adult fibrotic conditions should expand.

New ways to ventilate newborns in acute respiratory failure.

Out treatment options for acute neonatal failure have expanded greatly in the last 20 to 30 years. This article reviews patient-triggered ventilation, high frequency ventilation, negative extrathoracic pressure ventilation, nitric oxide therapy, liquid ventilation, extracorporeal membrane oxygenation, and advances in pulmonary function monitoring. The authors present background theories, describe equipment, review clinical strategies, and the results of recent trials.

Calculous disease of the biliary tract in infants after neonatal extracorporeal membrane oxygenation.

Extracorporeal membrane oxygenation (ECMO) can be lifesaving support for neonates with fulminant respiratory failure. In the 121 patients that we have placed on ECMO since 1983, bleeding, infection, and intracranial hemorrhage have constituted most of the major complications. We have also encountered two cases of biliary calculi in post-ECMO infants. The hemolysis, total parenteral nutrition, diuretics, and prolonged fasting associated with ECMO may predispose neonates to early calculous disease of the biliary tract and may require surgical intervention. Evaluation of abdominal pain or jaundice in infants and children who have been supported with ECMO should include examination of the biliary tree. Cholecystectomy should be seriously considered for infants with cholelithiasis.

Appendicitis in children in the managed care era.

Acute appendicitis is the most common condition requiring emergency operation in children. Late appendicitis is still a major source of morbidity and potential mortality. It has been suggested that managed care programs are responsible for a delay in surgical referral and consequently an increased risk of morbidity and mortality. In light of the increasing use of managed care, the authors reviewed their experience with pediatric acute appendicitis in managed care and indemnity insurance patients. The charts of all pediatric appendectomy patients treated between January 1990 and March 1995 were reviewed. Payor status, surgical and pathological findings, hospital course, and follow-up findings were documented. If the operative note or the pathology report described the appendix as gangrenous or perforated, the case was considered to be late appendicitis. Group I patients had traditional indemnity insurance; group II patients were in our institution's managed care plan. One hundred two patients were identified (28 in group 1, 74 in group II). Late appendicits was found less often in the managed care group (21.6% v 42.9%; P < .01). This resulted in a lower rate of major complications (1.4% v 3.6%) and a lower overall complication rate (2.7% v 7.1%). Group II also had a shorter hospital stay (2.6 days v 4.5 days; (P < .01) and lower average hospital charges ($6,507 v $8,754 (P < .01). These results do not demonstrate any adverse affect on outcome for children with acute appendicitis who have a managed care plan. In fact, the incidence of late appendicitis among these patients was half of that of the indemnity-insured patients. The lower risk of late appendicitis resulted in a shorter length of stay and lower hospital charges. These results suggest that managed care programs can provide quality care along with a significant reduction in costs; no delay in appropriate surgical referral was demonstrated.

Isolated fetal mouse limbs: gestational effects on tissue repair in an unperfused system.

While it is known that adult tissue repair is tightly regulated through local effects in the wound environment mediated by circulating blood elements such as platelets, white cells, cytokines, and hormones, the degree to which each is required in fetal tissue repair is uncertain. This raises the following questions regarding regulation of fetal tissue repair: (1) is the local wound matrix alone sufficient to sustain fetal tissue repair in the same regenerative manner seen in previous in vivo whole animal studies? (2) Will it occur only during the period of rapid fetal growth and development in early and mid gestation? To address these fundamental questions, an organ culture system has been designed to grow isolated, unperfused, developing fetal mouse limbs in a chemically defined, serum-free media. Amputated fetal mouse forelimbs (n > or = 10) were wounded with linear incisions at gestational days 14, 16, and 18 (term = 19); the wounds were closed primarily. These amputated and wounded limbs were placed on steel grids in organ culture petri dishes, then partially submerged in a chemically defined, serum-free media. The limbs were grown at 37 degrees C in humidified 95% air/5% CO2 for 1 week. These wounded limbs were examined histologically at days 0, 3, and 7 postwounding to determine their viability and whether or not tissue repair occurred. In the 14-day group, limb growth and differentiation was evident during the incubation period. Normal dermal and epidermal architecture was restored at the wound site without abundant collagen deposition by day 7 postwounding.(ABSTRACT TRUNCATED AT 250 WORDS)

The potential role of the lymphocyte in fetal wound healing.

Wound healing is a complex process involving a number of different cell populations. Since fetal wounds contain only a small number of mononuclear cells and no fibrosis immunohistochemical techniques using monoclonal antibodies specific to T and B lymphocytes, as well as macrophages, were used to identify the mononuclear cells in fetal wounds and to compare the lymphocyte response with the adult wound healing response. Polyvinyl alcohol sponges were placed subcutaneously in fetal rabbits on day 24 of gestation (then 31 days). Adult rabbits underwent similar implantation. Implants (8 to 14 per group) were harvested 5 days later and examined by H&E and trichrome staining as well as immunohistochemical staining with monoclonal antibody (Mab) specific for rabbit T and B lymphocytes. The sponges in one group of fetal rabbits were impregnated with the polypeptide growth factor, transforming growth factor-beta (TGF-beta), a known regulator of adult tissue repair. Adult wounds showed an intense inflammatory response with extensive collagen deposition; 80% of the infiltrating cellular elements were T lymphocytes. Fetal wounds were less cellular with minimal collagen deposition; 40% of the cells were T lymphocytes. The fetal wounds treated with TGF-beta were intensely cellular and fibrotic with 71% of the cellular infiltrate comprised of T lymphocytes. The increased cellularity of the TGF-beta wounds appears to be primarily the result of increased numbers of T lymphocytes. These findings demonstrate that the fetus mounts an attenuated T lymphocyte response compared to the adult. The increased response of T lymphocytes with TGF-beta suggests that the specific growth factor milieu may account for the fetal response to wounding.(ABSTRACT TRUNCATED AT 250 WORDS)

The anterior sagittal approach for high imperforate anus: a simplification of the Mollard approach.

High imperforate anus is a complex anomaly that requires a combination of careful preservation of native structures and precise anatomic reconstruction for optimal results. Previously the authors used an anterior perineal approach derived from the technique described by Mollard, with generally satisfactory results. The present report describes the authors' refinement of the technique to avoid skin perineal approach, via an anterior sagittal incision, usually is combined with a transverse suprapubic laparotomy. The technique includes division of the external sphincter and longitudinal muscle fibers anteriority, simple dilatation of the puborectalis, and division of the fistula close to the urethra, with preservation of the internal sphincter. The rectal pouch is brought down to the level of the puborectalis, without tapering, and the anoderm is brought up to the level of the rectal pouch to construct a shorter anal canal with a normal anorectal angle. This technique maximally preserves internal sphincter function, preserves specialized anoderm for the anal canal, and avoids extensive pelvic dissection and division of the levator sling. It also facilitates repair in the neonatal period, which may be optimal for long-term continence. The authors have used this technique in five patients, with good anatomic and short-term functional results. The authors believe that the technique provides optimal preservation of native tissues; only minimal destruction and dissection are required for reconstruction.

Pediatric extracorporeal membrane oxygenation in posttraumatic respiratory failure.

The leading cause of death in the pediatric population in the United States is trauma. A retrospective review of patients treated with extracorporeal membrane oxygenation (ECMO) for traumatic respiratory failure was performed. Eight children were treated at the Ochsner Medical Foundation and additional data on six children were available from the National Registry. Six children developed respiratory failure as a result of blunt trauma and eight as a result of near drowning. Standard venoarterial ECMO was used with a circuit very similar to that used in neonatal ECMO. Vascular access was via the common carotid artery and the internal jugular vein. Ventilatory support was weaned to minimal settings during ECMO. Central hyperalimentation and systemic antibiotics were used in all of the cases. Four of six children survived in the blunt trauma group; three of eight children survived in the near drowning group. Although significant conclusions cannot be drawn from a small group of patients the average pre-ECMO PO2 for survivors was 87 mm Hg, whereas for nonsurvivors the average PO2 was only 46 mm Hg. Ventilatory support for both groups was not remarkably different, and the average PCO2 was lower in the nonsurvivor group. The cause of death in this group of patients is usually multisystem organ failure. In the four patients treated at Ochsner who did not survive, all had positive blood cultures and presumed systemic sepsis. ECMO has been demonstrated to be very successful in neonatal respiratory failure. Predicting mortality and morbidity in pediatric respiratory failure has been more difficult.(ABSTRACT TRUNCATED AT 250 WORDS)

Salvage of Soave-Boley endorectal pull-through by conversion to a classical Soave procedure.

The endorectal pull-through procedure described by Soave and subsequently modified by Boley to include primary coloanal anastomosis is one of the most commonly performed procedures for Hirschsprung's disease. The Boley modification carries a 5-10% risk of dehiscence of the colo-anal anastomosis. This is generally treated with proximal colonic diversion and delayed revision of the pull-through. We report the use of the original Soave procedure to treat this complication.

The Bianchi procedure in a patient with jejunal atresia.

While small-bowel transplantation remains an option for the management of short-bowel syndrome (SBS), every effort must be made to optimize the function of the native bowel. This report describes a patient with SBS who dramatically improved after a Bianchi procedure. The patient was born with type IIIb jejunal atresia, complicated by volvulus of the terminal ileum. He was left with 40 cm of small bowel and his ileocecal valve. During the first 20 months of his life, he was always hospitalized except for 3 months. He was on parenteral nutrition (TPN) and suffered multiple episodes of central line sepsis. Massive small-bowel dilatation caused a functional bowel obstruction with bacterial overgrowth, and villous atrophy of the jejunal mucosa was discovered on biopsies done by colonoscopy. In March 1994, we elected to proceed with a Bianchi procedure. Thirty cm of jejunum were divided longitudinally. During the following year, his enteral tolerance steadily improved to the point where TPN could be discontinued. We conclude that pediatric surgeons should not hesitate to use this procedure in the management of SBS.

Reoperation for cysts of the thyroglossal duct.

OBJECTIVE: To determine the causes of recurrence of thyroglossal duct cysts (TDCs). DESIGN: A case series. SETTING: A university-affiliated children's hospital. PATIENTS: Between 1974 and 1990, 121 children were treated for TDCs. They ranged in age from 1 month to 18 years. Of these 121 children, 23 had recurrent TDC. INTERVENTIONS: Simple aspiration of the cyst, incision and drainage, cystectomy without hyoidectomy and the Sistrunk operation. MAIN OUTCOME MEASURES: Initial procedures that led to recurrence and procedures that resulted in cure. RESULTS: Six children had recurrence of TDCs after simple cystectomy without hyoidectomy; all were cured by the Sistrunk operation. Fourteen children with infected cysts initially underwent a variety of procedures with recurrence and were eventually managed by the Sistrunk operation. TDCs recurred in eight of these. Three children without infected cysts had recurrence after the Sistrunk operation. Of 34 TDCs infected initially, 40% recurred, whereas of 87 TDCs that were not infected initially, only 8% recurred. CONCLUSION: Simple cystectomy without hyoidectomy and pre-existing infection are the main causes of recurrence of TDCs.

Hyaluronate uptake and CD-44 activity in fetal and adult fibroblasts.

One of the unique aspects of fetal wounds is the persistence of a high concentration of hyaluronic acid (HA) in the extracellular matrix. Within the wound environment, both the synthesis and breakdown of this complex glycosaminoglycan are regulated predominately by the fibroblast with cell binding mediated by the membrane receptor CD-44. The ability of adult and fetal fibroblasts to incorporate fluorescent-labeled HA (F-HA) was measured, and the effect of a monoclonal antibody to CD-44 to block this uptake was studied. Fetal fibroblasts incorporated significantly greater F-HA than adult fibroblasts at the 4- and 6-hr times (P < 0.05), while CD-44 blockade reduced the uptake to background levels. These results demonstrate that fetal fibroblasts incorporate F-HA more rapidly than adult fibroblasts and that this uptake is mediated by the membrane protein CD-44.