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Biomedical subjects

B L Short

Publications and source records attributed to B L Short.

At least 19 recordsLinked to original sources
PubMed1998

Congenital diaphragmatic hernia survival and use of extracorporeal life support at selected level III nurseries with multimodality support.

BACKGROUND: Congenital diaphragmatic hernia (CDH) has been cited to have a mortality rate of 50%. There have been multiple studies at individual institutions demonstrating potential benefits from various strategies including extracorporeal life support (ECLS), delayed repair, and lower levels of ventilator support. There has been no multicenter survey of institutions offering these modalities to describe the current use of ECLS and survival of these infants. In addition, the relationship between the number of patients with CDH managed at an individual institution and outcome has not been evaluated. METHODS: We queried 16 level III neonatal intensive care centers on the use of ECLS and survival of infants with CDH who were treated during 2 consecutive years (1993 to 1995). Data are presented as mean +/- SEM, median, and range. RESULTS: Data were collected on 411 patients. Of these, 71% +/- 8% were outborn and 8% +/- 3% were considered nonviable. Overall survival of CDH infants was 69% +/- 4% (range, 39% to 95%). The survival rate of infants on ECLS was 55% +/- 4%, whereas survival of infants not requiring ECLS was significantly increased at 81% +/- 5% (p = 0.005). The mean rate of ECLS use was 46% +/- 2%. There was no correlation between the number of cases per year at an individual institution and overall survival, ECLS survival, or ECLS use (r = 0.341, 0.305, and 0.287, respectively). There was also no correlation between case volume at an individual institution and ECLS survival (r = 0.271). CONCLUSIONS: The current survival rate and rate of ECLS use in infants with CDH at level III neonatal intensive care units in the United States are 69% +/- 4% and 46% +/- 2%, respectively. There is no correlation between the yearly individual center experience with managing CDH and rate of ECLS use or outcome.

Extracorporeal Circulation↗
PubMed1997

Reduced airway resistance and work of breathing during mechanical ventilation with an ultra-thin, two-stage polyurethane endotracheal tube (the Kolobow tube).

OBJECTIVES: To compare dynamic pulmonary function studies using the ultrathin walled Kolobow endotracheal tube, with conventional endotracheal tubes of similar external diameter on rabbits during mechanical ventilation. To test the hypothesis that the increased internal diameter of the Kolobow tube will result in decreased airway resistance and work of breathing. DESIGN: Controlled animal study. SETTING: Institutional animal research facility. SUBJECTS: Adult female Dutch Belted rabbits (n = 6), weighing 1.4 to 1.6 kg. INTERVENTIONS: The animals were initially intubated with a conventional endotracheal tube (2.5-mm internal diameter; 3.6-mm outer diameter); they were paralyzed and placed on a mechanical ventilator. Ventilatory settings were adjusted to obtain standard arterial blood gases: pH of 7.35 to 7.45; PaCO2 of 35 to 40 torr (4.7 to 5.3 kPa), and PaO2 of 90 to 100 torr (12.0 to 13.3 kPa). After the stabilization period, pulmonary function tests (PFTs) were measured (period 1), the conventional endotracheal tube was replaced with a Kolobow tube, and PFTs were measured again and recorded (period 2). While continuously monitoring tidal volume, the peak inspiratory pressure was decreased to match the tidal volume measured during ventilation with the conventional endotracheal tube. Once the desired tidal volume was reached, PFTs were recorded (period 3). Flows were unchanged during the experiment and the length of the endotracheal tubes was the same for both the conventional and the Kolobow tube. MEASUREMENTS AND MAIN RESULTS: Mean values of the airway resistance and work of breathing from periods 1 and 3 were compared using the Student's t-test. There was a 59% decrease in total airway resistance (p = .001) and 45% decrease in the work of breathing (p = .0006). CONCLUSIONS: The use of the ultrathin walled Kolobow endotracheal tube resulted in significant decreases in airway resistance and work of breathing, which has the potential for improving the ventilatory mechanics in very small premature newborns.

Airway Resistance↗
PubMed1997

Extracorporeal membrane oxygenation exposes infants to the plasticizer, di(2-ethylhexyl)phthalate.

OBJECTIVES: To determine the exposure to, and evaluate the potential toxicity from, the plasticizer, di(2-ethylhexyl)phthalate (DEHP) during extracorporeal membrane oxygenation (ECMO) therapy. DESIGN: Protocol 1 consisted of a prospective comparison of three ECMO circuit designs in vitro. Protocol 2 consisted of a prospective, comparative clinical study evaluating DEHP plasma concentrations in ECMO vs. non-ECMO patients with respiratory failure. SETTING: Neonatal intensive care unit at The Children's National Medical Center, Washington, DC. PATIENTS: In protocol 2, 28 consecutive term infants were referred for ECMO therapy. Eighteen infants required ECMO; ten control patients received conventional ventilation and improved without ECMO. INTERVENTIONS: In protocol 1, three ECMO circuit designs were primed in vitro with normal saline, albumin, and human blood, which was maintained at 37 degrees C and recirculated at 400 mL/min for 48 hrs. Plasma samples were obtained at time 0, 1 hr, and every 6 hrs. In protocol 2, ventilatory and cardiovascular management of the patients in the study was conducted by the attending physician. Patients were placed on ECMO when they met the institutional criteria for ECMO therapy. Daily plasma concentrations for DEHP were collected until 3 days after decannulation from bypass in the ECMO group. Control patients were sampled daily until extubation. Evidence of cardiac, liver, or lung toxicity was evaluated by Chest Radiographic Scores, liver function studies, and echocardiograms obtained on day 1, day 3, and the day of decannulation in the ECMO group, or at the time of extubation in the control group. Sedation, blood product transfusions as indicated, antibiotics, and hyperalimentation were administered to all patients. MEASUREMENTS AND MAIN RESULTS: All DEHP plasma concentrations were measured by gas chromatography. In protocol 1, three circuits were studied: circuit A (small surface area); circuit B (larger surface area); and circuit C (surface area of A but with heparin-bonded tubing in the circuit). DEHP leached from circuit A at 0.32 +/- 0.12 microgram/ mL/hr, compared with 0.57 +/- 0.14 microgram/mL/hr from circuit B (p < .05). This amount of DEHP extrapolates in the ECMO patient to a potential exposure of 20 to 70 times that exposure from other medical devices or procedures, such as transfusions, dialysis, or short-term cardiopulmonary bypass. Circuit C showed almost no leaching from the circuit; DEHP concentrations decreased at a rate of 0.2 +/- 0.04 microgram/mL/ hr. In protocol 2, DEHP was undetected in the control patients. DEHP concentrations in ECMO patients were greater in the early course of ECMO. However, most patients cleared this compound from the plasma before decannulation. In contrast to the in vitro results in protocol 1, the average highest concentration at any time on bypass was 8.3 +/- 5.7 micrograms/mL or 2 mg/kg. CONCLUSIONS: DEHP leaches from ECMO circuits, with potential exposure concentrations related to the surface area of the tubing in the ECMO circuit. Heparin bonding of the tubing eliminates this risk. Although significant concentrations of DEHP leach from the nonheparin-bonded circuits over time, our in vivo studies showed that the DEHP plasma concentrations were less than the previously reported values and do not correlate with any observable short-term toxicity. This compound may be either efficiently metabolized by the newborn, or redistributed into various tissues. Although signs of toxicity were not found in this study, long-term complications from chronic exposure to DEHP have not been determined.

Diethylhexyl Phthalate↗
PubMed1997

Effect of nitric oxide in meconium aspiration syndrome after treatment with surfactant.

OBJECTIVE: To test the hypothesis that inhaled nitric oxide may be an effective therapeutic agent in meconium aspiration syndrome and may improve oxygenation after pretreatment with surfactant. DESIGN: Prospective, interventional study. SETTING: The animal research laboratory at The Children's National Medical Center. SUBJECTS: Eight newborn pigs, 1 to 2 wks of age, 4.1 +/- 0.4 kg, were used for the study. INTERVENTIONS: Animals were anesthetized, paralyzed, intubated, and mechanically ventilated. Catheters were placed in the femoral vein and artery, and in the pulmonary artery. After 1 hr of recovery, 10 mL/kg of 20% meconium in normal saline solution was insufflated into the lungs. Animals were ventilated to maintain arterial blood gases in a normal range (i.e., pH of 7.35 to 7.45, Paco2 of 40 to 45 torr [5.3 to 6.0 kPa], and Pao2 of 70 to 90 torr [9.3 to 12.0 kPa]). Ventilatory settings were increased, as needed, until the following maximum settings were reached: FIO2 of 1.0; peak inspiratory pressure of 40 cm H2O; and intermittent mandatory ventilation of 60 breaths/min. After 2 hrs of conventional ventilation or demonstration of clinically important lung disease by failure to maintain desired blood gases on the maximum ventilatory settings, 4 mL/kg of beractant was given intratracheally. After a short period of stabilization following surfactant therapy, inhaled nitric oxide was administered. Concentrations of 40, 20, and 10 parts per million were given. To assure that there was no additive effect of inhaled nitric oxide, each dose was given for 20 mins, followed by a 15-min normalization period at 0 parts per million. MEASUREMENTS AND MAIN RESULTS: Physiologic measurements, ventilatory settings, arterial blood gases, and methemoglobin were recorded at each study period. Measurements were taken after each exposure to inhaled nitric oxide and after its discontinuation. Arterial oxygen saturation and Pao2 were significantly lower after meconium aspiration when compared with baseline values. After treatment with surfactant, administration of inhaled nitric oxide improved oxygenation without a significant decrease in pulmonary arterial pressure. CONCLUSIONS: In this model of meconium aspiration syndrome, short-term exposure to inhaled nitric oxide after treatment with surfactant improved oxygenation secondary to better distribution of inhaled nitric oxide. The increase in oxygenation may be secondary to an improved ventilation/perfusion mismatch, since the primary etiology of hypoxia in this model may be a combination of parenchymal lung disease and pulmonary hypertension.

Administration, Inhalation↗
PubMed1997

Use of intratracheal pulmonary ventilation versus conventional ventilation in meconium aspiration syndrome in a newborn pig model.

OBJECTIVE: To determine whether intratracheal pulmonary ventilation (ITPV) allows for effective oxygenation and ventilation at lower mean airway pressures and peak inspiratory pressures than conventional ventilation in a piglet model of meconium aspiration syndrome. DESIGN: Prospective, interventional study. SETTING: The animal research laboratory at Children's National Medical Center, Washington, DC. SUBJECTS: Twenty newborn piglets, 2 to 7 days of age, weighing 1.8 to 2.8 kg. INTERVENTION: Animals were anesthetized, paralyzed, intubated, and ventilated. Femoral arterial and venous catheters were inserted; 5 mL/kg of 20% meconium in normal saline was instilled into the endotracheal tube. Animals were randomized to either ITPV or conventional ventilation, and settings were adjusted to maintain ideal blood gases, i.e., pH 7.35 to 7.45, PCO2 40 to 45 torr (5.3 to 6 kPa), PO2 80 to 100 torr (10.7 to 13.3 kPa), and SaO2 > or = 90%. Ventilatory settings were adjusted as needed to a maximum of: FIO2 1.0, peak inspiratory pressure 40 cm H2O, positive end-expiratory pressure 5 cm H2O, and respiratory rate 80 breaths/min. MEASUREMENTS AND MAIN RESULTS: Arterial blood gases were taken every 30 mins for 4 hrs and ventilatory settings were adjusted to maintain optimal blood gases. Heart rate, mean arterial blood pressure, and arterial saturation were monitored continuously. The animals in the ITPV group had significantly lower peak inspiratory pressure at 1, 2, 3, and 4 hrs after meconium instillation (p < .018) and significantly lower mean airway pressure at 2, 3, and 4 hrs after meconium instillation (p < .03). The mean peak inspiratory pressure in the ITPV animals ranged from 17 +/- 2.7 cm H2O at baseline to 16.6 +/- 5.7 cm H2O at 4 hrs compared with 16.5 +/- 2.7 cm H2O at baseline to 31.8 +/- 9.1 cm H2O at 4 hrs in the conventionally ventilated animals (p < .04). The mean airway pressure ranged from 6.3 +/- 1.1 mm Hg at baseline to 6.8 +/- 2.5 mm Hg at 4 hrs in the ITPV group compared with 5.5 +/- 1.2 mm Hg at baseline to 10.7 +/- 3.4 mm Hg at 4 hrs in the conventional ventilation group (p < .03). The lungs of the ITPV animals were less hemorrhagic and had less pathologic evidence of injury than the lungs of the conventionally ventilated animals. CONCLUSIONS: These results indicate that ITPV can be used to effectively ventilate and oxygenate piglets with meconium aspiration syndrome at lower mean airway pressures and peak inspiratory pressures than conventional ventilation. This lower pressure causes less injury to the lungs of the animals.

Animals↗
PubMed1997

Severity of brain injury following neonatal extracorporeal membrane oxygenation and outcome at age 5 years.

Neurodevelopmental evaluation in childhood provides an opportunity to study complex neurological compensation following documented neonatal brain injury, and furnishes important clinical information which may have an impact on patient care. We studied 152 term children treated with extracorporeal membrane oxygenation (ECMO) as neonates and who received routine neonatal neuroimaging and comprehensive neurodevelopmental evaluation at age 5 years. The cohort was divided into four groups based on an independent neuroimaging score: No lesion, N=88; Mild lesion, N=38; Moderate lesion, N=12; and Severe lesion, N=14. Standardized testing at age 5 included complete neuropsychological assessment, neurological evaluation, and assessment of motor function. All testing was conducted without knowledge of the neuroimaging score. The occurrence of disability by severity of neuroimaging was: No lesion=10%; Mild=13%; Moderate=33%; Severe=57%. The relative risk within the ECMO population for disability at age 5 after moderate or severe neonatal lesion was 4.3 (CI=1.0 to 17.5) and 11.7 (CI=3.3 to 41.3), respectively. The remaining non-disabled children who had moderate to severe lesions functioned within normal limits. Severity of neonatal neuroimaging was inversely associated with IQ scores, pre-academic skills, and neuromotor function. The effect size was small but the rank order was predictable. Our data identify in 5-year-old children an impact of brain lesion severity demonstrated on routine neonatal neuroimaging. The results indicate potential compensation following moderate and severe lesions, and suggest a subtle but consistent influence of even mild neonatal brain injury.

Central Nervous System Diseases↗
PubMed1996

Right diaphragmatic eventration simulating a congenital diaphragmatic hernia.

We describe an infant with severe eventration of the right diaphragm and pulmonary hypoplasia who presented like a newborn with congenital diaphragmatic hernia complicated by persistent pulmonary hypertension. Surgical correction while on extracorporeal life support was unsuccessful due to attachments of the liver which prevented reduction into the abdominal cavity and our inability to distinguish the true defect from complete agencies of the right hemidiaphragm. At autopsy the pulmonary remnant and the fibrous membrane separating it from the liver were identified.

Diagnostic Errors↗
PubMed1996

Impairment of cerebral autoregulation during venovenous extracorporeal membrane oxygenation in the newborn lamb.

OBJECTIVE: To study the effects of venovenous extracorporeal membrane oxygenation (ECMO) on cerebral autoregulation in the newborn lamb. DESIGN: Animal studies, using newborn lambs, with comparison of two randomized treatment groups. SUBJECTS: Newborn lambs of mixed breed, 1 to 7 days of age, were randomized into two study groups: control animals, with jugular vein ligation but no ECMO (n = 6), and ECMO animals placed on venovenous ECMO (n = 6). SETTING: Laboratory animal facilities of the Department of Anesthesiology and Critical Care Medicine at The Johns Hopkins Medical Institutions, Baltimore, MD. INTERVENTIONS: Animals were anesthetized with pentobarbital, intubated, and ventilated, and monitoring catheters were inserted. Control animals had their right jugular vein ligated, and a cerebral autoregulation curve was performed after 1 hr of stabilization. ECMO animals were placed on venovenous ECMO and after 1 hr of stabilization, they had a cerebral autoregulation curve performed. Cerebral autoregulation was examined by increasing intracranial pressure, thereby decreasing cerebral perfusion pressure. Intracranial pressure was increased by infusion of artificial cerebrospinal fluid into the lateral ventricle of the brain. MEASUREMENTS AND MAIN RESULTS: Four ranges of cerebral perfusion pressure were evaluated: a) baseline (1 hr after initiation of bypass in venovenous ECMO or completion of surgery in controls); b) cerebral perfusion pressure of 55 to 40 mm Hg; c) cerebral perfusion pressure of 39 to 25 mm Hg; and d) cerebral perfusion pressure of < 25 mm Hg. Cerebral blood flow (radiolabeled microspheres), cerebral oxygen consumption, fractional oxygen extraction, and oxygen transport values were calculated at each study period. In ECMO animals, cerebral blood flow (cerebral hemispheres) decreased from a baseline measurement of 46 +/- 9 (SD) mL/100 g/ min to 29 +/- 12 mL/100 g/min at a cerebral perfusion pressure of < 25 mm Hg. In the control group, cerebral blood flow was unchanged from baseline at any range of cerebral perfusion pressure. Cerebral oxygen consumption was unchanged from baseline as cerebral perfusion pressure decreased in either group. When cerebral oxygen consumption was compared between the two groups, it was lower in the ECMO group at baseline and at a cerebral perfusion pressure of < 25 mm Hg. At a cerebral perfusion pressure of < 25 mm Hg, cerebral blood flow, cerebral oxygen delivery, and metabolic rate were lower in the ECMO group than in the control group, and fractional oxygen extraction and cerebral vascular resistance were higher, indicating that autoregulation was impaired. There was no difference between blood flow in the right and left cerebral hemispheres when autoregulation was impaired in the ECMO animals. CONCLUSIONS: These findings indicate that cerebral autoregulation was altered in animals on venovenous ECMO, with cerebral blood flow decreasing at a cerebral perfusion pressure of < 25 mm Hg, compared with control animals which showed no changes at the same cerebral perfusion pressure. This disruption of cerebral autoregulation decreased cerebral oxygen metabolism despite an increased oxygen extraction in ECMO animals.

Animals↗
PubMed1996

Intracranial abnormalities in infants treated with extracorporeal membrane oxygenation: update on sonographic and CT findings.

PURPOSE: To determine the frequency of intracranial lesions in infants treated with extracorporeal membrane oxygenation (ECMO), to evaluate trends in frequency during an 8-year period, and to determine which infants are at highest risk for intracranial injury. METHODS: Daily sonograms were obtained in 386 infants during treatment with ECMO. Cranial CT scans were acquired after decannulation in 286 of 322 survivors. Abnormalities were classified as major or minor and hemorrhagic or nonhemorrhagic. Results were correlated with infant demographic data. RESULTS: Intracranial abnormalities were detected in 203 (52%) of the 386 infants; 73 (19%) hemorrhagic, 86 (22%) nonhemorrhagic, and 44 (11%) combined lesions. Eighty-two lesions (21%) were classified as major. Forty-six (94%) of 49 major hemorrhages were identified at sonography. CT contributed additional information in 73% of neonates with intracranial abnormalities, of which 17 were major lesions not identified at sonography. The frequency of intracranial hemorrhage was increased in infants who were septic or premature or weighed less than 2.5 kg. An increase in time spent on ECMO bypass increased the risk for nonhemorrhagic injury. During an 8-year period, the frequency of hemorrhagic and major nonhemorrhagic lesions remained constant, whereas minor nonhemorrhagic abnormalities increased significantly. CONCLUSION: Infants treated with ECMO continue to be at high risk for cerebrovascular injury. Although daily sonograms are useful in identifying major hemorrhages, follow-up CT scans are crucial for accurate evaluation of intracranial abnormalities.

Brain Damage, Chronic↗
PubMed1995

Experience with abdominal wall closure for patients with congenital diaphragmatic hernia repaired on ECMO.

Congenital diaphragmatic hernia (CDH) and its attendant lack of abdominal domain can create major technical challenges with respect to diaphragmatic and abdominal wall reconstruction, especially in seriously ill infants who require extracorporeal membrane oxygenation (ECMO). The authors reviewed the medical records of all infants with CDH repaired on ECMO at their institution (group 1, 15 patients), and compared them with infants having CDH repair before ECMO (group 2, 20 patients) and with those who had CDH repair but did not require ECMO (group 3, 15 patients). Thirty-seven of 50 patients survived (74%): 10 in group 1, 12 in group 2, and all 15 in group 3. There was a statistically significant difference (P < .001) with respect to the requirement of a polytetrafluoroethylene (PTFE) diaphragmatic patch for patients in group 1 versus those in both groups 2 and 3. There was also a significant difference in the number of patients in whom the abdomen could not be closed (P < .001 for group 1 v groups 2 and 3). Infants who require ECMO before CDH repair are more likely to have large diaphragmatic defects that require prosthetic reconstruction, and abdominal wall closure problems resulting from loss of abdominal domain, which further complicate the management of the physiological derangements from pulmonary hypoplasia and persistent pulmonary hypertension.

Abdominal Muscles↗
PubMed1995

Neurodevelopmental status at age five years of neonates treated with extracorporeal membrane oxygenation.

OBJECTIVE: To determine the neurodevelopmental status at age 5 years among children who received extracorporeal membrane oxygenation (ECMO) in the newborn period as a treatment for severe cardiorespiratory failure. METHODS: We conducted a prospective cohort study of 103 five-year-old ECMO-treated children born between June 1984 and July 1988, and treated at our institution. Thirty-seven healthy control children were recruited locally. The assessment protocol included a complete neuropsychologic assessment, psychosocial assessment with parent questionnaires, a standard neurologic evaluation, assessment of gross motor and fine motor function, a medical history, and physical examination. RESULTS: Major disability was present in 17 of the ECMO cohort. Eleven ECMO-treated children (11%) were mentally retarded, one of whom was profoundly impaired. Two additional children had severe learning disabilities. Cerebral palsy was diagnosed in 5 (5%) ECMO-treated children, but all cases were mild in nature and the patients were walking unaided. One child has paraplegia. The mean Full Scale, Verbal, and Performance IQs of the EMCO-treated children were within the normal range, but as a group were significantly lower than in control children (96 vs 115, p < 0.001). Children treated with ECMO had increased risk relative to the control children for academic difficulties at school age (49% VS 22%, P < 0.01) and a higher rate of behavioral problems reported by parents (42% vs 16%, p = 0.01). CONCLUSIONS: The rate of major disability was comparable to that in other high-risk populations. The high rate of behavioral problems and increased risk of subsequent school failure among nonretarded ECMO-treated children supports the need for close follow-up of these children after hospital discharge.

Child Development↗
PubMed1995

Improved oxygenation with reduced recirculation during venovenous extracorporeal membrane oxygenation: evaluation of a test catheter.

OBJECTIVE: To determine whether modifications of the original design of a double-lumen, venovenous, extracorporeal membrane oxygenation (ECMO) catheter would reduce recirculation and improve oxygenation during venovenous ECMO. DESIGN: Prospective, interventional study. SETTING: The animal research laboratory at The Children's National Medical Center. SUBJECTS: Six newborn lambs, 1 to 7 days old and weighing 4.7 +/- 0.9 kg. INTERVENTIONS: Animals were anesthetized, intubated and ventilated. The ductus arteriosus was ligated. Femoral artery and vein, cephalic jugular vein, and pulmonary artery catheters were placed. After systemic heparinization, the test catheter (with venous drainage holes moved away from the arterial return holes) was placed in the right internal jugular vein and advanced into the right atrium. The animal was placed on ECMO and stabilized, with the ventilator settings decreased to a peak inspiratory pressure of 15 cm H2O, peak positive end-expiratory pressure of 5 cm H2O, respiratory rate of 15 breaths/min, and an FIO2 of 0.21. ECMO flows were increased in 100-mL increments from 200 to 600 mL/min, with measurements taken 15 mins after each change. The test catheter was removed, the double-lumen, venovenous ECMO catheter was placed, and the studies were repeated. MEASUREMENTS AND MAIN RESULTS: Heart rate, mean arterial pressure, PaO2, jugular cerebral oxygen saturation, pulmonary artery oxygen saturation, mixed venous oxygen saturation, and postmembrane circuit pressures were measured at each study period. The test catheter improved oxygenation significantly, with higher systemic PaO2, higher pulmonary artery and cerebral oxygen saturations, and lower mixed venous oxygen saturations (indicating less recirculation). With the test catheter, PaO2 levels ranged from 62 +/- 6 torr (8.3 +/- 0.8 kPa) to 112 +/- 12 torr (14.9 +/- 1.6 kPa), compared with 46 +/- 4 torr (6.1 +/- 0.5 kPa) to 59 +/- 2 torr (7.9 +/- 0.3 kPa) for the double-lumen, venovenous ECMO catheter (p < or = .001). These findings indicate that at all flow rates studied, less recirculation occurred with the test catheter than with the double-lumen, venovenous ECMO catheter. CONCLUSIONS: These findings indicate that the redesign of the double-lumen, venovenous ECMO catheter, as outlined in this study, resulted in a significant reduction of recirculation, thereby resulting in a significant improvement in oxygenation while on venovenous ECMO. This newly designed catheter makes venovenous ECMO more effective, and represents a design that could be used for pediatric and/or adult ECMO.

Animals↗
PubMed1995

Neonates treated with ECMO: predictive value of early CT and US neuroimaging findings on short-term neurodevelopmental outcome.

PURPOSE: To determine if neuroimaging findings in infants who undergo extracorporeal membrane oxygenation (ECMO) are predictive of developmental outcome. MATERIALS AND METHODS: At 1-2 years of age, 183 ECMO survivors (69 female, 114 male) underwent developmental examination. Neuroimaging studies obtained at time of ECMO were assigned a neuroimaging score. Neuroimaging findings were correlated with developmental outcome. RESULTS: Eighty-five infants had neuroimaging abnormalities. Development was normal in 105 infants, suspect in 37, and delayed in 41. Mean neuroimaging scores were significantly worse in survivors with delayed development (P < or = .0001). The sensitivity and specificity of normal neuroimaging findings in prediction of normal outcome were 65% and 63%, respectively. Survivors with nonhemorrhagic abnormalities had a higher risk of delayed development than did those with isolated hemorrhagic abnormalities (39% vs 21%). CONCLUSION: Although they cannot be used alone to predict outcome, early neuroimaging scores can be used to assign risk categories for developmental outcome.

Brain↗
PubMed1995

Congenital diaphragmatic hernia. Outcome of preoperative extracorporeal membrane oxygenation.

In recent years, increasing numbers of patients with congenital diaphragmatic hernia (CDH) have been offered extracorporeal membrane oxygenation (ECMO) preoperatively if they can not physiologically tolerate early surgical repair. These infants are sicker are more unstable than those repaired pre-ECMO and, in most cases, have not had a "honeymoon" period (i.e., PaO2>100 mm Hg at some point). ECMO before surgical repair was offered to 27 CDH patients in our institution; of the 16 (59%) survivors, 11 are now 2 years of age to older. To determine the outcome risk for this critical population, we compared 11 infants placed on ECMO pre-CDH repair (Group A) with our previous series of 22 survivors who had their surgery prior to ECMO (Group B). Both groups were similar in birth weight, gestational age, and Apgar scores. In Group A, a greater number were females (73% vs 23%), had right-sided hernia (64% vs 23%), and required patch repairs (82% vs 23%). The mean time on ECMO, time to extubation, and mean length of hospitalization were longer in group A. In both groups combined, the frequency of reherniation was higher in the patch-repair infants compared with those with a primary closure. Incidence of reflux was high in both groups, with increasing frequency of Nissen fundoplication in Group A patients (45% vs 6%). Both groups demonstrated similar delayed growth at 1 year of age. Although infants placed on ECMO presurgery are sicker, with more post-ECMO morbidity, their growth failure is similar to the less sick infants repaired pre-ECMO.(ABSTRACT TRUNCATED AT 250 WORDS)

Apgar Score↗
PubMed1994

The cerebrovascular response to prolonged hypoxia with carotid artery and jugular vein ligation in the newborn lamb.

This study was designed to evaluate the effect of ligation of the carotid artery and/or jugular vein, after exposure to prolonged (4 hours) hypoxia, and the effect of acute normalization of PaO2 after prolonged hypoxia with vessel ligation, on the cerebral circulation. Twelve 1- to 7-day-old lambs were anesthetized with pentobarbital. Catheters were placed in the femoral artery and vein, left ventricle, lingual artery, and sagittal sinus. Cerebral blood flow (CBF) was determined using the radiolabeled microsphere technique. After baseline studies, the animals were made hypoxic with a nitrogen/air mixture, to lower PaO2 to 36 +/- 5 mm Hg for 4 hours, followed by 1 hour of normoxia. After four hours of hypoxia, studies were performed. The animals were divided into two groups to evaluate carotid artery and jugular vein ligation separately. In group I, the carotid artery was ligated first, with studies performed after 5 minutes; this was followed by ligation of the jugular vein, with studies after 5 minutes. In group II, the jugular vein was ligated first, with studies after 5 minutes; this was followed by ligation of the carotid artery, with studies after 5 minutes. With regard to physiological variables, there were no differences between the groups. CBF increased 106% (P < .001 compared with the baseline value) after 4 hours of hypoxia, maintaining cerebral oxygen consumption (CMRO2) and oxygen transport (OT) constant in both groups. Ligation of either the carotid artery or jugular vein after 4 hours of hypoxia, did not alter CBF responses to hypoxia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Surfactant (beractant) therapy for infants with congenital diaphragmatic hernia on ECMO: evidence of persistent surfactant deficiency.

Infants with congenital diaphragmatic hernia (CDH) on extracorporeal membrane oxygenation (ECMO) can have initial lung atelectasis which, in survivors, gradually improves over time. To test the hypothesis that these patients could benefit from surfactant therapy, infants with CDH (born at > 34 weeks' gestation) on ECMO received either four doses of modified bovine lung surfactant extract (beractant) (surfactant group, n = 9) or an equal volume of air (control group, n = 8). Tracheal aspirate surfactant protein-A (SP-A) concentrations were initially low, and then increased over time in both CDH groups (P = .0021); however, levels remained low when compared with those of infants on ECMO who had other diagnoses (P = .04). Lung compliance (CL), time to extubation, time on oxygen, and total no. of hospital days were not different between the two groups. Infants with CDH had persistently elevated right ventricular pressure (RVP) at cessation of bypass when compared with non-CDH infants on ECMO (RVP = 53.25 mm Hg +/- 19.52 in the CDH group, 32.90 +/- 10.63 in the non-CDH group; P = .0121). The findings suggest that the postnatal surfactant deficiency may be more persistent in CDH infants than in non-CDH infants on ECMO. However, CDH remains a multifactorial condition, with delayed improvement, because of persistence of pulmonary hypertension, difficulties with vascular remodeling, degree of lung hypoplasia, or compromised respiratory mechanics.

Airway Resistance↗