High-Frequency Oscillatory Ventilation and Nitric Oxide: Alternative or Complementary to ECMO

One hundred and seventy-seven term or near-term neonates were referred to an ECMO center for severe PPHN-associated diseases. In 2 time periods from 1987 to 1991 and from 1992 to April 1995 alternative treatment modes were tried in an attempt to obviate ECMO. During the first time period patients underwent trial high-frequency oscillatory ventilation before ECMO. In the second time period patients first received inhaled NO followed by HFOV in a non-responders. If this also failed HFOV was combined with I NO. In both time periods about 40% of the patients were spared ECMO treatment by these alternative treatment modalities. I NO only benefited 15% of the ECMO candidates who apparently had fared just as well on HFOV alone in the preceding time period. While patients who were improved by I NO were spared HFOV with its potential severe complications, i.e. air leaks and cardiocirculatory instability, more extended long-term studies will have to show which of these 2 treatment modalities (INO or HFOV) should be given first priority in an attempt to avoid ECMO in neonates with severe respiratory failure.

Expanded application of extracorporeal membrane oxygenation in a pediatric surgery practice

OBJECTIVE

To examine the breadth of application and resulting outcomes in a university-based extracorporeal membrane oxygenation (ECMO) program directed by pediatric surgeons.

SUMMARY BACKGROUND DATA

Several randomized control trials have supported the use of ECMO in neonates with respiratory failure. No comparable data exist for older children and young adults who may be afflicted with a variety of uncommon conditions. The indications for ECMO in these patients remain controversial.

METHODS

Patient data were recorded prospectively and reported to the Extracorporeal Life Support Organization. These data were analyzed by indications and outcomes on all patients treated since the inception of the program.

RESULTS

Two hundred sixteen patients were treated with 225 courses of ECMO. Neonates (188 [87%]) outnumbered 28 older patients (aged 6 weeks to 22 years). Overall, 174 patients survived (81%). Sixty-four of 65 (98.5%) neonates with meconium aspiration syndrome survived. ECMO support after heart (3), lung (2), heart-lung (1), and liver (1) transplant yielded a 57% survival to discharge. ECMO also resulted in survival of patients with uncommon conditions, including severe asthma (1), hydrocarbon aspiration (1/2), congestive heart failure due to a cerebral arteriovenous malformation (1), tracheal occlusion incurred during endoscopic stent manipulation (2), meningitis (1), and viral pneumonia (3/5).

CONCLUSIONS

ECMO can potentially eliminate mortality for meconium aspiration syndrome. Survival for other causes of respiratory failure in neonates and older children, while not as dramatic, still surpasses that anticipated with conventional therapy. Moreover, survival of transplant patients has been comparable to that achieved in other children.

Inhaled nitric oxide and gentle ventilation in the treatment of pulmonary hypertension of the newborn--a single-center, 5-year experience

OBJECTIVE

To evaluate the effect of inhaled nitric oxide (INO) in pulmonary hypertension of the newborn (PH) in a single center over 5 years using gentle ventilation (GV), without hyperventilation or induced alkalosis.

METHODS

Data from 229 consecutive infants with PH of varied etiology treated with INO and GV, and from 67 infants with meconium aspiration syndrome (MAS) and primary PH (PPHN) treated with GV alone were reviewed over a 5-year period (86% outborn). INO was initiated at 25 ppm when PH and severe hypoxemia persisted despite maximal optimal ventilation. Hyperventilation or systemic alkalosis were not attempted.

RESULTS

Mean duration of ventilation was 9.9 +/- 14 days (median 6.5 days). Average mean airway pressure (MAP) dropped from 17.7 +/- 4.3 cm H(2)O at the referral hospital to 13.2 +/- 2.5 cm H(2)O (p < 0.001) following admission to our unit using conventional settings and GV, before starting INO. Mean oxygenation index (OI) dropped from 46.8 +/- 24.5 to 22.7 +/- 21.4 within 24 hours of INO therapy (p < 0.001). Infants with higher baseline pH and lower baseline OI responded better to INO (p < 0.02). Overall survival was 72%. Patients with MAS and PPHN had the best response, 92% survived and there was a 46% reduction in need for extracorporeal membrane oxygenation (ECMO) compared to historical pre-INO period controls (23.9% vs. 12.8%, p < 0.01). In the infants treated with GV alone, the MAP dropped from 17.2 +/- 4.3 cm H2O at the referral hospital to 12.6+/-2.4 after GV was started in our unit.

CONCLUSIONS

We conclude that INO is an effective and well-tolerated therapy for PH in infants receiving GV.

Elective extracorporeal membrane oxygenation: an improved perioperative technique in the treatment of tracheal obstruction

The surgical management of children with tracheal stenosis and obstruction is complicated by the perioperative needs of pressure ventilation and indwelling endotracheal tubes. These factors predispose to surgical failure and anastomotic breakdown, restenosis. and pneumomediastinum. The use of extracorporeal membrane oxygenation (ECMO) to manage ventilation during tracheal repair allows better visualization at the surgical site and obviates the need for indwelling endotracheal tubes and high-pressure ventilation. Six children were treated with elective ECMO at a tertiary care hospital. All 6 underwent successful surgical repair, and 4 of the 6 were ultimately extubated. There were no significant complications at the surgical site. There was 1 death from postoperative complications, and 2 patients required tracheotomy. One tracheotomy was performed for upper airway obstruction secondary to retrognathia, and this patient was subsequently decannulated. Medical complications were confined to 2 patients and included sepsis, hyperbilirubinemia, seizure disorder, renal failure, intracranial hemorrhage, and hydrocephalus. Elective ECMO provides a reliable perioperative technique for airway management of children with tracheal stenosis or obstruction. This technique offers the advantage of improved visibility at the operative site and eliminates the need for high-pressure ventilation, thereby likely reducing the risk of perioperative morbidity.

Respiratory failure. Conventional and high-tech support

Although significant progress has been made in the treatment of patients with acute lung failure in the critical care setting, the mortality rate from acute lung injury and ARDS is unacceptably high, given the numbers of patients treated for these syndromes each year. The improved understanding of the pathophysiology of respiratory failure from basic science and clinical research is reflected in improved survival rates over the years. Advances in the mechanical ventilator (through microprocessor technology); biosurface technology; liquid ventilation; and, in some cases, returning to so-called "antiquated" practices of patient care (e.g., prone positioning) seem to have had an impact nonetheless. As refinement continues to occur in these areas, morbidity and mortality from lung failure will have a lesser impact on patients as physicians treat the consequences of organ failure in the ICU.

Neurodevelopmental outcome in ECMO vs near-miss ECMO patients at 5 years of age

The objective of this study was to compare the outcome of children at 5 years of age who were treated with extracorporeal membrane oxygenation (ECMO) and those who were critically ill but did not meet ECMO criteria, identified as near-miss ECMO. In one of the longest studies of its kind, we compared the neurodevelopmental outcome of 76 5-year-old ECMO-treated children with 20 5-year-old near-miss ECMO patients with similar primary diagnoses. The two groups were compared for demographic data, level of ventilatory support, and degree of hyperventilation. The comprehensive assessment protocol included an assessment of intelligence (IQ), attainment of preacademic and early academic skills, and parents' report of adaptive behavior. Both groups had similar demographic data and primary diagnosis. The near-miss ECMO patients required increased ventilatory support but not significantly more than the ECMO patients. The cognitive outcome was similar in both groups with mean estimated Full-Scale IQ in the normal range for near-miss and ECMO groups (89 and 97, respectively). Rates of severe mental handicap (FSIQ < 70) (near-miss = 11%, ECMO = 12%) and risk for school failure (near-miss = 38%, ECMO = 37%) were also similar. More parents of near-miss ECMO patients reported immature adaptive skills than did parents of ECMO patients, although the numbers were small in each group. Rates of parent-reported child behavior problems were similar in both groups. ECMO and near-miss ECMO patients have similar cognitive and adaptive outcomes at 5 years of age. A significant number in each group are at risk of school failure and should be closely followed up.

Devices and monitoring during neonatal ECMO: survey results

A survey of active ECMO centres regarding neonatal ECMO equipment and personnel was obtained by telephone interview in late summer 1989. Forty-seven of the centres in the USA listed in the Ann Arbor ELSO (Extracorporeal Life Support Organization) Registry at the time ( greater than 90%) were contacted and all participated. Nearly all use a roller pump, while less than 5% use a centrifugal pump. All programmes use a SciMed membrane oxygenator and 90% a SciMed heat exchanger. Heat exchanger water sources include the Gaymar T-pump (42%), Seabrook (25%) and Cincinnati Sub-Zero (23%) units. Eighty-seven per cent use a bladder box servo-regulated to the roller pump; these are most often custom-made (69%) but 13% of programmes use a commercially available (Seabrook) bladder box. Ten per cent use a pressure-regulated roller pump rather than a conventional (displacement) bladder box to detect decreases in venous return. Nearly 80% monitor circuit line pressures between the pump and patient. Seventeen per cent use an air bubble detector on the arterial side of the circuit. Only 10% use an arterial bubble trap and 6% an arterial line filter. Seventy-five per cent do not monitor gas line pressures into the membrane lung, but one-third do use a gas line pop-off valve to prevent elevated gas phase pressures. Seventy per cent reported use of continuous in-line measurement of mixed venous oxygen saturation; no programme reported any blood chemistries being monitored in line.(ABSTRACT TRUNCATED AT 250 WORDS)

Can blood gas values predict pulmonary hypoplasia in antenatally diagnosed congenital diaphragmatic hernia?

The prognosis of antenatally diagnosed congenital diaphragmatic hernias (CDH) is clearly related to the degree of pulmonary hypoplasia (PH). After birth, controversies remain regarding the implementation of various therapies, especially the use of extracorporeal membrane oxygenation (ECMO). In the literature, the persistence of a Pao2 below 100 mm Hg and of Paco2 above 40 mm Hg despite optimal conventional therapy indicates poor prognosis. Therefore, since 1992, published and personal experiences led the authors to exclude CDH patients from ECMO when conventional therapy (including high-frequency oscillatory ventilation and nitric oxide) did not obtain Pao2 of above 80 mm Hg and Paco2 of below 60 mm Hg. The aim of this retrospective study is to determine whether blood gas results correlate with postmortem findings. Between July 1990 and July 1994, 32 cases of CDH were monitored antenatally and managed postnatally at the authors' institution. Six patients survived; 26 died, including one immediately at birth. Thirteen were treated by ECMO. Seventeen had a best Pao2 of above 80 mm Hg, including the six survivors. Fourteen did not reach this level, and none of them survived. Twenty-three infants underwent postmortem examination. PH was assessed using two criteria: (1) lung weight to body weight ratio (LW/BW) and (2) radial alveolar count (RAC). Two patients did not have hypoplasia (LW/BW > 0.018). Twenty-one patients had PH; 12 of them had an LW/BW ratio of less than .009; for 9, the LW/BW ratio was between .009 and .018, and the RAC (< 3.1) confirmed PH. All infants with a best Pao2 of less than 80 mm Hg had PH. Patients with a best Pao2 of greater than 80 mm Hg included two infants who died from complications without PH, eight infants with demonstrated PH, and the six survivors. In conclusion. (1) No infant with nonhypoplastic lungs has been deprived of ECMO by the authors' criteria. (2) Adequate values of blood gases may not eliminate PH. Therefore, this probably justifies starting ECMO when conventional therapy fails. (3) Conversely, permanent poor values of Pao2 allowed the prediction of PH in all cases. Such patients probably can be excluded from ECMO treatment.

Cerebral blood flow and carbon dioxide reactivity in neonates during venoarterial extracorporeal life support

OBJECTIVES

a) To determine if cerebral blood flow is symmetric after internal carotid artery and ipsilateral internal jugular vein ligation in infants during venoarterial extracorporeal life support. b) To determine the cerebral CO2 reactivity (delta cerebral blood flow/delta torr CO2) of neonates during venoarterial extracorporeal life support and its correlation to neurodevelopmental outcome.

DESIGN

Prospective, clinical study.

SETTING

University hospital pediatric intensive care unit.

PATIENTS

Fourteen neonates with respiratory failure who were receiving venoarterial extracorporeal life support.

INTERVENTIONS

PaCO2 was altered by adjusting the CO2 gas flow through the membrane oxygenator. Cerebral blood flow was measured over both parietal-temporal regions at three PaCO2 values using xenon-133 clearance methodology. Cerebral blood flow measurements were made early (< or = 12 hrs of extracorporeal life support, n = 10) or late (> or = 48 hrs of extracorporeal life support, n = 10). In six of 14 infants, both early and late cerebral blood flow rates were measured. PaO2, mean arterial pressure, pump flow rate, and temperature were stable during each study period. Neurodevelopmental outcome was assessed in the neonatal follow-up clinic.

MEASUREMENTS AND MAIN RESULTS

Right and left hemispheric cerebral blood flow rates were significantly correlated with each other during early and late extracorporeal life support (p = .0001; r2 = .91). Overall, hemispheric cerebral blood flow was statistically symmetric. There was no association of CO2 reactivity (delta cerebral blood flow/delta torr PCO2, range 0.04 to 1.36 mL/min/100 g/torr) with short-term neurodevelopmental outcome. Infants with normal neurodevelopmental outcome had variable CO2 reactivity (range 0.04 to 0.67 mL/min/100 g/torr). Normal short-term neurodevelopmental outcome was observed in two infants with cerebral blood flow of < 10 mL/min/100 g.

CONCLUSIONS

Hemispheric cerebral blood flow was symmetric in infants during early and late venoarterial extracorporeal life support. Some subgroups showed a trend toward decreased right hemispheric cerebral blood flow, but the small number of patients limited interpretation of this finding. CO2 reactivity and cerebral blood flow were highly variable in this population, and were not predictive of short-term neurodevelopmental outcome. Stressed neonates with extremely low cerebral blood flow rates may have relatively normal short-term neurodevelopmental outcome after venoarterial extracorporeal life support.

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.

Doppler echocardiographic assessment of pulmonary circulation in severe respiratory failure of the neonate: an aid for extracorporeal lung support indications

Extracorporeal lung support (ECLS) for newborns with acute respiratory failure has achieved increased popularity over the last decade. However, precise criteria for its implementation remain controversial. The aim of this study was to assess the value of Doppler echocardiography (DE) in 31 neonates with PaO2 of < or = 50 mmHg, FIO2 of 1, and optimal ventilation. Treatment included mechanical ventilation, paralysis, volume loading, vasopressors, and tolazoline. Markers indicative of ECLS (failure of maximal medical therapy, assessed by AaDO2 of more than 610 mm Hg beyond 8 hours and/or an oxygenation index (OI = mean airway pressure x FIO2%/postductal PaO2) of more than 40 beyond 4 to 6 hours) were present in 23 (group 1) and absent in eight (group 2). Shunt direction and systolic pulmonary arterial pressure (sPAP) calculated from tricuspid insufficiency velocity were assessed using DE. At the time of admission, sPAP was significantly higher in group 1 (62.1 v 43.7 mm Hg). On day 1, group 1 differed from group 2 in maximum sPAP value (73.2 v 44.4 mm Hg), PaCO2 (56.1 v 40 mm Hg), right-to-left shunting (85% v 25% of the patients), and pulmonary-to-systemic-pressure systolic ratio (sPAP:sSAP) (1.29 v 0.75). Patients with an sPAP:sSAP ratio of more than 1 and patients with high sPAP associated with high PaCO2 on day 1, all later (average, 10 hours later) fulfilled ECLS criteria; this suggests that DE assessment of pulmonary circulation may yield early and predictive markers of impending ECLS indication. Further confirmation of these results would help avoid unnecessary delays in ECLS implementation in newborns with severe respiratory failure.

Malposition of extracorporeal membrane oxygenation cannulas in patients with congenital diaphragmatic hernia

We describe two infants with congenital diaphragmatic hernia who underwent extracorporeal membrane oxygenation and in whom the venous cannula was in the left atrium instead of the right. The routine radiograph of the chest failed to demonstrate the malposition. We recommend using the echocardiogram to confirm the position of the cannula or to guide the surgeon during the cannulation of patients with congenital diaphragmatic hernia.

Characterization of the neonatal heart rate baroreflex during and after ECMO

Prolonged continuous blood pressure (BP) and heart rate (HR) recordings from neonates of 35 to 42 weeks gestation were studied during and after ECMO. Data segments with significant deviation of BP were extracted for further analysis. The simultaneous changes in BP and HR were compared and the slope of the regression determined baroreflex sensitivity (BRS). Of 464 BP deviations, 98% produced curves with a negative slope consistent with the presence of a baroreflex. The average BRS was -1.0 +/- 0.8 bpm/mmHg (mean +/- S.D.) and curves were steeper during rising BP than falling BP (-1.1 +/- 0.9 beats/min per mmHg versus -0.9 +/- 0.6, P = 0.001). The baroreflex was more sensitive during ECMO than after ECMO to both rising BP (-1.0 +/- 0.5 beats/min per mmHg versus -0.7 +/- 0.5, P = 0.004) and falling BP (-1.0 +/- 0.6 beats/min/mmHg versus -0.7 +/- 0.5, P = 0.04). HR response curves obtained during different BP fluctuations on the same recording had varying threshold, consistent with acute resetting. One infant demonstrated chronic baroreceptor resetting over 3 days to a rise in resting BP. The near-term, critically ill neonate has an active baroreflex which is capable of resetting. ECMO was associated with accentuation of the baroreflex response.

A clinical-pathological study of nonsurvivors of newborn ECMO

Extracorporeal membrane oxygenation (ECMO) is an important means of supporting newborns with respiratory failure. While short- and long-term follow-up of ECMO survivors has been thoroughly addressed, there is no systematic study of nonsurvivors. Nineteen nonsurvivors of newborn ECMO with autopsy results are divided into two groups: group 1: 12 patients who had intracranial lesions as the primary cause of death (hemorrhage 8, encephalomalacia 2, infarct 2); and group 2: 7 patients with nonintracranial primary causes of death. Patients in group 1 were significantly more acidotic, hypotensive, and smaller in age and birth weight pre-ECMO. Among group 2 patients, two with diaphragmatic hernia died of primary pulmonary disease (diffuse alveolar damage, pulmonary hypoplasia and necrosis, bronchopneumonia). One of 2 patients with persistent fetal circulation (PFC) was treated with massive doses of tolazoline and suffered fatal gastrointestinal hemorrhage and ischemic necrosis of heart, spleen, testes, and adrenals. The other PFC patient had severe pulmonary interstitial fibrosis. Two patients with meconium aspiration and a patient with streptococcal sepsis had diffuse pulmonary damage and multiple organ failure (renal medullary necrosis, and infarcts of adrenal, spleen, liver). In this series, intracranial pathology was the most common cause of death in ECMO patients, related to gestational age, acidosis, hypoxia, and size, but probably unrelated to carotid ligation.

Effects of hydralazine on cardiac performance in infants receiving extracorporeal membrane oxygenation

To determine the effects of afterload reduction on cardiac performance during partial cardiopulmonary bypass, we administered hydralazine to infants who were either normotensive (n = 11) or hypertensive (n = 12) 1 hour after extracorporeal membrane oxygenation (ECMO) was begun. Load-dependent and load-independent measures of cardiac performance and indexes of cerebral blood flow were measured. Infants in both groups had similar weight, heart rate, blood pressure, and inotropic support before ECMO. Shortening fraction was normal in both groups before ECMO (47 +/- 11% vs 49 +/- 10%; p greater than or equal to 0.05), decreased during ECMO (31 +/- 18% vs 39 +/- 12%; p greater than or equal to 0.05), and did not change after administration of hydralazine (31 +/- 12% vs 37 +/- 8%; p greater than or equal to 0.05). Cardiac output was normal in both groups before ECMO (176 +/- 71 vs 157 +/- 72 ml/kg per minute; p greater than or equal to 0.05), decreased during ECMO (120 +/- 80 vs 105 +/- 64 ml/kg per minute; p greater than or equal to 0.05), and did not change after hydralazine administration. Velocity of circumferential fiber shortening, an index of contractility (circumference per second), was normal in both groups before ECMO (1.96 +/- 0.57 vs 1.90 +/- 0.43 circ/sec; p greater than or equal to 0.05), decreased during ECMO (1.18 +/- 0.83 vs 1.56 +/- 0.58 circ/sec; p greater than or equal to 0.05), and did not change after hydralazine administration. The relationship between velocity of circumferential fiber shortening and wall stress was similar in both groups before ECMO, during ECMO, and after hydralazine administration. The cerebral blood flow resistance index was similar in both groups before ECMO (0.70 +/- 0.16 vs 0.70 +/- 0.20; p greater than or equal to 0.05), decreased during ECMO (0.45 +/- 0.13 vs 0.43 +/- 0.09; p greater than or equal to 0.05), and did not change after administration of hydralazine. We conclude that hydralazine does not improve cardiac performance during ECMO.

Cardiac performance in infants referred for extracorporeal membrane oxygenation

We performed cardiac evaluations in 59 infants referred for severe lung disease to determine whether cardiac performance was impaired in those requiring extracorporeal membrane oxygenation (ECMO). Infants were divided into two groups: group 1 (n = 25) received conventional therapy and group 2 (n = 34) received ECMO therapy after meeting established criteria. Ventilatory and oxygenation indexes and estimates of right ventricular systolic pressure were measured. Load-dependent and load-independent echocardiographic indexes of cardiac performance were also measured. The infants in the two groups had similar diagnoses, age, weight, inotropic support, ventilator and oxygenation indexes on admission, and survival. Heart rate and estimates of preload and afterload were similar in the two groups. Ventricular shortening fraction was 36.1 +/- 7.6% in group 1 and 40.5 +/- 8.8% in group 2 (p value was not significant). Velocity of circumferential fiber shortening (VCF/sec) was 1.41 +/- 0.35 in group 1 and 1.58 +/- 0.39 in group 2 (p value was not significant). The relationship between wall stress and ventricular shortening was similar in the two groups. There were no differences in cardiac output. Pulmonary artery pressure was estimated to be 56 +/- 13 mm Hg in group 1 and 63 +/- 10 mm Hg in group 2 (p = 0.017). Thus no significant differences were found in load-dependent or load-independent measures of cardiac performance in infants with severe lung disease treated with ECMO or conventional therapy. We conclude that cardiac failure is not the primary cause of clinical deterioration in infants with severe lung disease who require ECMO therapy.

Extracorporeal membrane oxygenation therapy in neonates with septic shock

Neonatal septic shock has significant morbidity and mortality with current therapeutic measures. At Children's National Medical Center, from June 1984 to October 1986, 10 of 100 patients treated with venoarterial extracorporeal membrane oxygenation (ECMO) had a documented diagnosis of septic shock. All of these infants fulfilled criteria consistent with 80% mortality using conventional intensive medical management. However, the survival rate for the septic neonates in this study was 100%. Compared with other groups of infants treated with ECMO, these septic neonates required significantly more ventilatory support after ECMO and had a higher incidence of chronic lung disease (30% v 12%). The septic neonates were also at higher risk for intracranial hemorrhage than the other infants treated with ECMO (40% v 26%). The necessity for prolonged intubation after ECMO for patients with septic shock suggests that this condition may be associated with additional structural damage not seen with meconium aspiration syndrome or respiratory distress syndrome. Nevertheless, for neonatal patients with septic shock unresponsive to conventional medical management, ECMO must be considered a viable alternative treatment.

Use of extracorporeal membrane oxygenation in the treatment of respiratory syncytial virus bronchiolitis: the national experience, 1983 to 1988

In an effort to obtain data to provide the basis for the design of controlled clinical trials, we contacted all U.S. participants in the National ECMO Registry to assemble the national experience on the use of extracorporeal membrane oxygenation in respiratory syncytial virus bronchiolitis during the past 5 years. Twelve infants were treated at nine centers between 1983 and 1988. Eight had been born prematurely, and five had bronchopulmonary dysplasia. The mean age at onset of infection with respiratory syncytial virus was 108 +/- 102 days. The mean length of ventilator management before extracorporeal membrane oxygenation was 7.8 +/- 7.1 days. All infants had persistent hypoxemia with a mean arterial oxygen pressure of 39.2 +/- 11.7 torr (5.3 +/- 1.6 kPa) despite high ventilator pressures (mean airway pressure 19.7 +/- 6.4 cm H2O) and 100% inspired oxygen; six had air leak syndrome. Seven infants survived (58%). The mean duration of extracorporeal membrane oxygenation for survivors was 233 +/- 139 hours. Preexisting chronic lung disease did not predict a poor outcome: four of the five infants with bronchopulmonary dysplasia survived. Six of the survivors have subsequently achieved expected developmental milestones and one has slight motor delay. We conclude that, for infants with severe respiratory syncytial virus bronchiolitis whose condition deteriorates despite maximal ventilator management, extracorporeal membrane oxygenation may provide lifesaving support. The duration of successful treatment with this therapy may be longer than that for conventional neonatal indications, but excellent neurologic outcome may be expected in survivors.

Surfactant protein A concentrations in tracheal aspirate fluid from infants requiring extracorporeal membrane oxygenation

To understand the lung abnormalities leading to respiratory failure in infants, we measured 35,000-dalton surfactant protein A concentrations in tracheal aspirate fluid collected daily from 25 infants receiving extracorporeal membrane oxygenation (ECMO). Surfactant protein A concentrations were standardized per milligrams of total protein present in the aspirate. Among the 23 survivors with complete data, the surfactant protein A concentration increased significantly with time (p less than 0.0001). Concurrent increases in lung compliance (p less than 0.0001) and radiographic scores (p less than 0.0001) were also observed. This increase in surfactant protein A content may reflect lung recovery from barotrauma and oxygen toxic effects or be a response to the primary pulmonary disease process. The two infants who did not survive extracorporeal membrane oxygenation failed to demonstrate these trends.

Doppler echocardiographic evaluation of cardiac performance in infants on prolonged extracorporeal membrane oxygenation

Cardiac performance was evaluated by Doppler echocardiography in 19 infants with persistent pulmonary hypertension before, during and after prolonged extracorporeal membrane oxygenation (ECMO). Systemic arterial pressure was normal before ECMO (67 +/- 12 mm Hg), increased during ECMO (78 +/- 13 mm Hg) and decreased to baseline after ECMO (p less than or equal to 0.01). Heart rate was normal before ECMO and did not change during or after ECMO. The left ventricular shortening fraction was normal before ECMO (37 +/- 11%), decreased after beginning ECMO (25 +/- 11%) and returned to baseline 72 hours after beginning ECMO (p less than or equal to 0.01). Pulmonary arterial and aortic blood flow velocities were normal before ECMO, decreased 30 to 50% during ECMO and increased to baseline 72 hours after beginning ECMO (p less than or equal to 0.01). Stroke volume had an identical trend (p less than or equal to 0.01). Left ventricular velocity of circumferential shortening--an index of contractility--decreased after beginning ECMO (p less than or equal to 0.05). Left ventricular systolic wall stress--an index of systemic afterload--increased after beginning ECMO (p less than or equal to 0.01). A patent ductus arteriosus was present in 13 of 19 infants before ECMO, 16 of 19 infants during ECMO and in none of 19 infants after ECMO. Pulmonary arterial systolic pressure was high before ECMO (72 +/- 25 mm Hg), began to decrease after 48 hours on ECMO (59 +/- 24 mm Hg) and was normal after ECMO (38 +/- 18 mm Hg), p less than or equal to 0.05.(ABSTRACT TRUNCATED AT 250 WORDS)

To-and-for extracorporeal lung assist (ECLA) through a single catheter-in premature goats as an experimental model of infant respiratory Insufficiency

A new to-and-fro V-V bypass extracorporeal lung assist (ECLA) through a single catheter as a blood access was investigated for its efficacy on six premature goats delivered by Cesarean section at a gestational age of 118 approximately 139 days as an experimental model of infant respiratory insufficiency, then applied to a human premature infant suffering from life threatening barotrauma that had developed from mechanical pulmonary ventilation. The extracorporeal bypass flow and the gas flow to the artificial membrane lung were controlled to keep Pa(O)(2) above 40 mmHg and Pa(CO)(2) within normal limits. The neonate's own lungs were treated with a continuous positive airway pressure of 5 approximately 12 cmH(2)O, apneic oxygenation or IMV. Two goats weighing 1250 g and 700 g died 2 approximately 2.5 hours after birth from severe circulatory distress. However, the other four neonates which were heavier than 2000 g, were successfully weaned from ECLA, and three of these could be weaned from mechanical ventilation as well. A human infant also survived and was weaned from ECLA on the third day.(Tanoue T, Terasaki H, Sadanaga M et al.: To-and-fro extracorporeal lung assist (ECLA) through a single catheter-in premature goats as an experimental model of infant respiratory insufficiency.

Treatment of neonatal necrotizing tracheobronchitis with extracorporeal membrane oxygenation and bronchoscopy

Necrotizing tracheobronchitis has recently been described as a complication of mechanical ventilation of newborns with respiratory failure. Despite the use of bronchoscopy, 45% of the reported patients to date have died. In this study, we report the use of extracorporeal membrane oxygenation (ECMO) to stabilize two patients with necrotizing tracheobronchitis. While supported by bypass, both patients underwent prolonged bronchoscopies with removal of extensive amounts of tracheal debris. ECMO provided efficient oxygenation in the face of near total airway occlusion, and permitted far more extensive bronchoscopic debridement and lavage than would have been possible if the lungs were required for oxygenation. In addition, ECMO provided a period of lung "rest" during which ventilator settings were reduced, thus minimizing further barotrauma and allowing for lung and airway healing. Both patients recovered without significant respiratory sequelae. ECMO and bronchoscopy are effective forms of therapy for patients with life-threatening necrotizing tracheobronchitis when conventional modalities of treatment have failed.