Criteria for extracorporeal membrane oxygenation in a population of infants with persistent pulmonary hypertension of the newborn

Administration of Inhaled Pulmonary Vasodilators to the Mechanically Ventilated Neonatal Patient

Pulmonary hypertension is a life-threatening condition that affects people of all ages that can occur as an idiopathic disorder at birth or as part of a variety of cardiovascular and infectious disorders. It is commonly treated with inhaled pulmonary vasodilators such as nitric oxide and less frequently using formulations and analogs of prostacyclin. To minimize systemic effects and preserve pulmonary vasodilation, vasodilators are often administered directly into the airway. Nitric oxide is the only USA Food and Drug Administration-approved inhaled pulmonary vasodilator that can be used during mechanical ventilation. Over the past two decades, interest has grown in the use of aerosolized prostacyclin and prostacyclin analogs for the treatment of pulmonary hypertension during mechanical ventilation. Clinicians who administer inhaled prostacyclin may not have a clear understanding of its risks because of the lack of data from large clinical trials examining safety and efficacy; moreover, its safe use remains poorly documented. The off-label use of drugs is legitimate, but prescribers must recognize the potential complications and liability in doing so. This manuscript aims to address potential problems related to the aerosol administration of pulmonary vasodilators in the mechanically ventilated neonatal patient.

An Economic Analysis of Extracorporeal Membrane Oxygenation

Financial considerations, in concert with clinical effec tiveness, are of increasing importance in the assessment of technological innovations. One such innovation, ex tracorporeal membrane oxygenation (ECMO), is now in use at over twenty centers nationwide to treat new borns with severe, acute lung disease. Use of ECMO therapy for one year at Children's Hospital National Medical Center, Washington, DC, in a population of pa tients with persistent pulmonary hypertension of the newborn (PPHN) is reported, comparing outcome and financial considerations with a similar group of infants treated conventionally prior to ECMO. A historical con trol group of infants with severe PPHN showed that before ECMO was available the survival rate in this criti cally ill population was only 21%. With ECMO, infants with the same clinical characteristics have an 80% chance of survival. Analysis of hospital and physician charges for these two groups (pre-ECMO and ECMO) reveals that ECMO therapy is about 2% less expensive than conventional treatment. When only survivors in each group are compared, ECMO is 43% less costly. These differences are attributable to reductions in aver age length of hospital stay with ECMO therapy, and they are conservative in that they do not take into considera tion the marked economic advantage to society of avert ing unnecessary deaths.

Brain injury associated with neonatal extracorporeal membrane oxygenation in the Netherlands: a nationwide evaluation spanning two decades

OBJECTIVE

To determine the prevalence of and to classify ultrasound-proven brain injury during neonatal extracorporeal membrane oxygenation in The Netherlands.

DESIGN

Retrospective nationwide study (Rotterdam and Nijmegen), spanning two decades.

SETTING

Level III university hospitals.

SUBJECTS

All neonates who underwent neonatal extracorporeal membrane oxygenation from 1989 to 2010.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Cranial ultrasound images were reviewed independently by two investigators without knowledge of primary diagnosis, outcome, type of extracorporeal membrane oxygenation, or statistics. The scans were reviewed for lesion type and timing, with the use of a refined classification method for focal brain injury. Extracorporeal membrane oxygenation type was venoarterial in 88%. Brain abnormalities were detected in 17.3%: primary hemorrhage was most frequent (8.8%). Stroke was identified in 5% of the total group, with a notable significant preference for the left hemisphere (in 70%). Lobar hematoma (prevalence 2.2 %) was also significantly left predominant.

CONCLUSION

The incidence of brain injury found with cranial ultrasound in The Netherlands of the patients treated with extracorporeal membrane oxygenation during the neonatal period was 17.3%. Primary hemorrhage was the largest group of lesions, not clearly side-specific except for lobar bleeding, most probably related to changes in venous flow. Arterial ischemic stroke occurred predominant in the left hemisphere.

Adapted ECMO criteria for newborns with persistent pulmonary hypertension after inhaled nitric oxide and/or high-frequency oscillatory ventilation

PURPOSE

Early prediction of extracorporeal membrane oxygenation (ECMO) requirement in term newborns with persistent pulmonary hypertension (PPHN), partially responding to inhaled nitric oxide (iNO) and/or high-frequency oscillatory ventilation (HFOV), based on oxygenation parameters.

METHODS

This was a retrospective cohort study in 53 partial responders from among 133 term newborns with PPHN born between 2002 and 2007. Alveolar-to-arterial oxygen gradient (AaDO₂) values were determined in these 53 partial responders during the initial 72 h of iNO and/or HFOV treatment and compared between newborns who ultimately did (n = 11) and did not (n = 42) need ECMO.

RESULTS

Over 72 h, partial responders not requiring ECMO showed a more profound AaDO₂ decrease than those who needed ECMO (median decline 242.5 mmHg, IQR 144 to 353 mmHg, vs. 35 mmHg, IQR -15 to 123 mmHg; p = 0.0007). A decline of <123 mmHg over 72 h predicted the need for ECMO (sensitivity 82 %, specificity 79 %). At 72 h, AaDO₂ was significantly lower in partial responders without the need for ECMO than in those who did need ECMO (median 369 mmHg, IQR 258 to 478 mmHg, vs. 570 mmHg IQR 455 to 590 mmHg; p = 0.0008). An AaDO₂ >561 mmHg at 72 h predicted the need for ECMO (sensitivity 64 %, specificity 95 %, positive predictive value 78 %).

CONCLUSIONS

In term newborns with PPHN partially responding to iNO and/or HFOV, oxygenation-based prediction of the need for ECMO appears to be possible after 72 h. ECMO centers are encouraged to develop their own prediction model in order to prevent both lung damage and unnecessary ECMO runs.

Extracorporeal Membrane Oxygenation for the Treatment of Neonatal Respiratory Failure

This review discusses the use of extracorporeal membrane oxygenation (ECMO) for the treatment of respiratory failure in neonates. After briefly reviewing the early history of neonatal ECMO, the authors describe the respiratory diagnoses most often treated with ECMO and the manner in which affected neonates are deemed to have “failed” conventional therapies and thus require ECMO. After reviewing the most common indications for ECMO, factors that influence the timing of conversion to extracorporeal life support, as well as criteria that may exclude patients from receiving ECMO therapy, are described. At the conclusion of this article, the authors discuss the long-term outcomes of neonates whose respiratory disease was treated with ECMO and the costs associated with that care.

Respiratory failure and extracorporeal membrane oxygenation

Conventional treatment of respiratory failure involves positive pressure ventilation with high concentrations of inspired oxygen. If adequate gas exchange still cannot be achieved extracorporeal membrane oxygenation (ECMO) may be an option. The general indication for ECMO for respiratory insufficiency is a reversible pulmonary disease, which cannot be managed by conventional means. ECMO is a modified heart-lung machine. Blood is withdrawn from a central vein in the patient and pumped through an artificial oxygenator back to the patient, either to a central artery (veno-arterial ECMO) or to a central vein (veno-venous ECMO). Total gas exchange can be achieved through the extracorporeal system, and the lungs do not have to be subjected to high-pressure ventilation. To date over 21,500 neonates have been treated with ECMO with an overall survival to hospital discharge of 76%. Meconium aspiration syndrome carries the highest survival (94%), whereas congenital diaphragmatic hernia on ECMO only has a survival of 52%. A total of 3500 pediatric patients (30 days to 18 years) have been treated with ECMO with a survival of 56%. Aspiration and viral pneumonia are the pediatric diagnoses with the highest survival rates. Randomized controlled studies have shown a significant advantage of ECMO with regard to survival in neonates. In the pediatric age group, nonrandomized studies have shown lower mortality in ECMO-treated patients.

Extracorporeal life support for severe adult respiratory failure

PURPOSE OF REVIEW

The past 35 years have provided a wealth of evidence that mechanical ventilation, although potentially life saving, can injure the lungs. Recent evidence suggests that limiting ventilating gas volumes can reduce patient mortality, but may result in progressive parenchymal derecruitment and alveolar hypoventilation, potentially aggravating systemic hypercarbia and hypoxemia. This review summarizes the current recommendations on a controversial, invasive technique termed 'extracorporeal life support' as a means to provide temporary pulmonary support during 'lung-protective' strategies.

RECENT FINDINGS

Extracorporeal life support has been implemented since the origins of cardiopulmonary bypass in the 1950s, but differs in several important ways from cardiopulmonary bypass, including its prolonged duration of application. Because extracorporeal life support serves only to supplement physiological derangements and is not therapeutic, patient selection critically impacts results. Whereas reversible neonatal processes such as meconium aspiration and persistent fetal circulation have fostered clinical trials demonstrating the efficacy of extracorporeal life support, adult cardiopulmonary failure extracorporeal life support trials have proved less compelling. Despite two prospective randomized trials that failed to demonstrate its efficacy, adult extracorporeal life support continues in limited centers of excellence. Adult extracorporeal life support survival rates for respiratory failure average 50% when strict criteria are met, but it remains unclear whether these results represent improved outcomes.

SUMMARY

Extracorporeal life support is an invasive technique that can provide support to the failing lung. Clinical trials have demonstrated its efficacy in neonatal and pediatric patients, but data in adults are less clear. An ongoing trial in the UK will soon address this important issue.

Long-term follow-up of patients with high-risk congenital diaphragmatic hernia

BACKGROUND/PURPOSE

Recent advances including prenatal diagnosis, high-frequency oscillatory ventilation, and nitric oxide inhalation therapy have gradually improved the survival of high-risk congenital diaphragmatic hernia. However, the factors affecting the long-term outcome of these patients have not been well established.

METHODS

Thirty-three children with ages 4.1 +/- 2.5 years underwent clinical examination including growth measurements, echocardiography, ventilation, and perfusion scintigraphy.

RESULTS

No late death was observed. Common complications were frequent respiratory tract infection (13 patients) and bowel obstruction (5 patients underwent surgery). Although frequent respiratory tract infection decreased with increasing age, patients with frequent respiratory tract infection had a decreased uptake of lung ventilation and perfusion scintigraphy on the affected side and had a decreased height for age and weight for height. No significant difference in lung ventilation and perfusion scintigraphy was observed between patients treated with and without extracorporeal membrane oxygenation, those requiring oxygen more than 1 month, and between those with and without prenatal diagnosis. Patients with a patch repair had decreased uptake on lung perfusion scintigraphy. Although frequent respiratory tract infection may be owing to hypoplasia of the ipsilateral lung, it may impair recovery of the hypoplastic lung.

CONCLUSION

These results indicate that monitoring for respiratory tract infection in addition to nutritional assessment should be required in the follow-up of patients with congenital diaphragmatic hernia at high risk.

ECMO for neonatal respiratory failure

Extracorporeal membrane oxygenation (ECMO) has been offered as a life-saving technology to newborns with respiratory and cardiac failure refractory to maximal medical therapy. ECMO has been used in treatment of neonates with a variety of cardio-respiratory problems, including meconium aspiration syndrome (MAS), persistent pulmonary hypertension of the neonate (PPHN), congenital diaphragmatic hernia (CDH), sepsis/pneumonia, respiratory distress syndrome (RDS), air leak syndrome, and cardiac anomalies. For this group of high-risk neonates with an anticipated mortality rate of 80% to 85%, ECMO has an overall survival rate of 84%, with recent data showing nearly 100% survival in many diagnostic groups. This article reviews the current selection criteria for ECMO and the clinical management of neonates on ECMO, and discusses the long-term outcome of neonates treated with ECMO.

Predicting outcome in neonatal hypoxic respiratory failure with the score for neonatal acute physiology (SNAP) and highest oxygen index (OI) in the first 24 hours of admission

OBJECTIVE

To determine the clinical utility of SNAP score versus the highest oxygen index (OI) in first 24 hours of admission in predicting outcome of HRF.

STUDY DESIGN

All admissions (1991 to 1999) > or =36 weeks gestation, ventilated for > or =12 hours with FiO(2)> or =0.50, without congenital anomalies were reviewed. Primary outcome measure was survival (without ECMO) versus ECMO and/or death.

RESULTS

From 184 infants with HRF, 148 survived (without ECMO) versus 36 died and/or received ECMO. SNAP score and highest OI were similar in predicting outcome of HRF (area under ROC curve: 0.813+/-0.037 versus 0.814+/-0.041; P=0.72). Death and/or ECMO requirement were best predicted by a SNAP score of 19 (Sensitivity 75.0%, Specificity 71%) or an OI of 28 (Sensitivity 75.0%, Specificity 76.4%).

CONCLUSION

Although both, the SNAP score and highest OI, are useful and similar in predicting outcome of HRF, OI is preferable because of its ease of use. We believe the predictive value of these parameters should be evaluated in a multicenter setting.

Update on extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) consists of the application of intermediate-term cardiopulmonary bypass for the treatment of potentially reversible heart and/or lung failure in the neonate, child, and adult. Applications in the neonate include congenital diaphragmatic hernia, pulmonary hypertension, meconium aspiration syndrome, and pre- and post-operative congenital heart surgery support. In the older child, myocarditis, infections, and respiratory failure (RSV and ARDS) are the most frequent indications, in addition to peri-operative cardiac surgical support. A review of the institutional experiences at the University of Louisville spanning a 15-year period and comparison international data will be presented, along with a pertinent review of the literature. Technical considerations, complications, and long-term outcomes will be reviewed, and the potential interface between ECMO and other, less invasive technologies, i.e., high-frequency ventilation, replacement surfactant, and nitric oxide, will be discussed.

Inhaled nitric oxide with early surgery improves the outcome of antenatally diagnosed congenital diaphragmatic hernia

BACKGROUND/PURPOSE

The outcome of antenatally diagnosed congenital diaphragmatic hernia (CDH) has remained poor despite aggressive therapeutic strategies. Since 1996, the authors have used a new approach including early surgery and inhaled nitric oxide (iNO). The aim of this study is to determine whether early surgery in combination with iNO improves the clinical outcome of antenatally diagnosed CDH.

METHODS

From 1988, 40 consecutive neonates with antenatally diagnosed CDH were admitted to the authors' hospital. Ten cases of fatal chromosomal anomalies or major cardiac anomalies were excluded from this study. From 1988 through 1995 (period 1: n = 13), delayed surgery was used in high-risk CDH. From 1996 through 2000 (period 2: n = 17), early surgery in combination with iNO was used. The severity of lung hypoplasia was evaluated using the fetal lung/thorax transverse area ratio (L/T). High-frequency oscillatory ventilation (HFOV) was used routinely during the study periods, and extracorporeal membrane oxygenation (ECMO) was used on basis of conventional entry criteria. The authors compared the clinical outcome, use of ECMO, and the L/T between the 2 periods retrospectively.

RESULTS

Patients in the 2 periods were comparable in terms of birth weight, gestational age, and the L/T. The mean age at surgery was 3.1 +/- 4.9 days in period 1, and 0.8 +/- 1.1 days in period 2. Fewer infants in period 2 compared with period 1 were treated with ECMO (period 1, 62% v period 2, 6%; P <.01). There was significant difference in the survival rate between the 2 periods (period 1, 38% v period 2, 94%; P <.01).

CONCLUSION

Our data suggest that early surgery and iNO improves the outcome and reduces the requirement of ECMO in the treatment of antenatally diagnosed CDH.

Persistent pulmonary hypertension of the newborn. Rational therapy based on pathophysiology

Persistent pulmonary hypertension of the newborn is a common disorder among near-term gestation newborns. Persistent pulmonary hypertension of the newborn is characterized by hypoxemia that is frequently refractory to conventional management. This article describes the pathophysiologic basis of the disorder and the current therapy that is based on this knowledge.

The current status of neonatal extracorporeal membrane oxygenation

Marked changes have occurred in the practice of neonatal extracorporeal membrane oxygenation (ECMO) since the first survivor in 1975. Coagulation management has been markedly refined, new catheters allow ECMO to be done either in a venoarterial or venovenous (VV) mode, depending on cardiac function in the infant. A new design of the VV catheter will allow this technique to be used in more infants in the future. New therapies for respiratory failure have changed the complexion of the population being treated with ECMO. The 34 to 36 week gestation infant with respiratory distress syndrome and/or pulmonary hypertension rarely needs ECMO therapy due to the effectiveness of surfactant and high frequency oscillation. Present day survival for infants treated with ECMO for many diagnostic categories ranges between 90% to 100%. The effects of new interventions must be evaluated with regard to their effect on morbidity when being considered prior to ECMO. Neuro-developmental outcome is encouraging, but does indicate that ECMO and the near-miss ECMO patients need to be followed closely into school age. The number of patients being treated per ECMO center has dropped significantly over the last 10 years from 18 to 9. This brings forward the question about regional needs for ECMO Centers and how to assure that centers have enough patients to maintain their clinical competencies. The challenge for the future is where to place ECMO as a therapy. Should it remain a rescue therapy? Or should there now be a trial comparing ECMO to conventional therapies, with morbidity and cost of care as the outcome variables?

Airway anomalies in patients with congenital diaphragmatic hernia

PURPOSE

Congenital diaphragmatic hernias (CDH) sometimes are associated with airway anomalies such as congenital stenosis, abnormal branching of the bronchi, and pulmonary hypoplasia. The incidence of these associated airway anomalies has not been reported previously.

METHODS

Bronchoscopy was performed in all neonates with CDH from 1987 to 1999. In addition to anatomic anomalies, bronchial hypoplasia was defined as narrowing and shortening of the bronchi at bronchoscopy.

RESULTS

Anatomic anomalies were identified in 7 of 39 patients with CDH: 1 had congenital tracheal stenosis with pulmonary artery sling, 1 had a defect of the right upper lobe bronchus, 2 had a tracheal bronchus, and 3 had a trifurcated trachea. Bronchial hypoplasia on the affected side was identified in 15 patients and was seen in all patients with anatomic anomalies of the tracheobronchial tree except the 2 with tracheal bronchus. After excluding 5 patients with severe associated anomalies, 6 of 14 patients with an abnormal tracheobronchial tree died, whereas 1 of 20 patients without airway abnormalities died.

CONCLUSIONS

Anatomic anomalies of the tracheobronchial tree and bronchial hypoplasia on the affected side were identified in 17.9% and 38.4% of patients with CDH, respectively. CDH patients who exhibited these abnormalities showed a poor outcome.

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.

Prognosis of pediatric bone marrow transplant recipients requiring mechanical ventilation

OBJECTIVES

To assess the prognosis of pediatric bone marrow transplant recipients requiring mechanical ventilation and to identify risk factors for mortality.

DESIGN

Retrospective chart review.

SETTING

Pediatric intensive care unit (PICU), tertiary care center.

PATIENTS

Inclusion criteria were endotracheal intubation and mechanical ventilation after bone marrow transplantation; patients with perioperative ventilation were excluded. Outcome measures were extubation, PICU discharge, and 6-month survival. The 39 patients who met the inclusion criteria were ventilated on 41 occasions.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Overall survival rate to PICU discharge was 44% (17 of 39 patients). Six months after PICU discharge, 14 of these children were still alive, for a medium-term survival rate of 36%. Preexisting conditions (primary disease, bone marrow engraftment, or graft-vs.-host disease) had no significant effect on survival. Multiple organ failure, especially pulmonary failure and neurologic deterioration, were significant determinants of patient survival.

CONCLUSIONS

The observed prognosis is improved over previous reports. Early initiation of aggressive intensive care treatment is warranted in this patient group. Decisions regarding intensity of treatment must be based on aspects of the acute illness rather than on the primary conditions.

An overview of extracorporeal membrane oxygenation therapy

A brief overview of extracorporeal membrane oxygenation and its use in infants and children is presented. The history, selection, operative procedure, daily management and complications are discussed. The international results are shown.

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.

Purine metabolism and inhibition of xanthine oxidase in severely hypoxic neonates going onto extracorporeal membrane oxygenation

The effect of allopurinol to inhibit purine metabolism via the xanthine oxidase pathway in neonates with severe, progressive hypoxemia during rescue and reperfusion with extracorporeal membrane oxygenation (ECMO) was examined. Twenty-five term infants meeting ECMO criteria were randomized in a double-blinded, placebo-controlled trial. Fourteen did not receive allopurinol, whereas 11 were treated with 10 mg/kg after meeting criteria and before cannulation, in addition to a 20-mg/kg priming dose to the ECMO circuit. Infant plasma samples before cannulation, and at 15, 30, 60, and 90 min, and 3, 6, 9, and 12 h on bypass were analyzed (HPLC) for allopurinol, oxypurinol, hypoxanthine, xanthine, and uric acid concentrations. Urine samples were similarly evaluated for purine excretion. Hypoxanthine concentrations in isolated blood-primed ECMO circuits were separately measured. Hypoxanthine, xanthine, and uric acid levels were similar in both groups before ECMO. Hypoxanthine was higher in allopurinol-treated infants during the time of bypass studied (p = 0.022). Xanthine was also elevated (p < 0.001), and uric acid was decreased (p = 0.005) in infants receiving allopurinol. Similarly, urinary elimination of xanthine increased (p < 0.001), and of uric acid decreased (p = 0.04) in treated infants. No allopurinol toxicity was observed. Hypoxanthine concentrations were significantly higher in isolated ECMO circuits and increased over time during bypass (p < 0.001). This study demonstrates that allopurinol given before cannulation for and during ECMO significantly inhibits purine degradation and uric acid production, and may reduce the production of oxygen free radicals during reoxygenation and reperfusion of hypoxic neonates recovered on bypass.

Changes in alveolar-arterial oxygen difference and oxygenation index during low-dose nitric oxide inhalation in 15 newborns with severe respiratory insufficiency

We evaluated changes in alveolar-arterial oxygen differences (AaDO2) and oxygenation index (OI) during inhalation of low-dose nitric oxide (INO) in 15 newborns with severe respiratory insufficiency: congenital diaphragmatic hernia (CDH) -6, asphyxial lung disease -4, meconium aspiration syndrome (MAS) -2, respiratory distress syndrome -2, persistent pulmonary hypertension of newborn -1. Their mean birth weight was 2522 g (1030-3200 g, SD +/- 575), mean gestational age 36 weeks (29-39 weeks, SD +/- 3.2), mean initial AaDO2 = 607 mm Hg (574-628 mm Hg, SD +/- 14) and mean initial OI = 32 (6-57, SD +/- 12). INO was performed using the Pulmonox system (Messer Griesheim, Austria) at conventional regimens of mechanical ventilation. The initial value of 20 ppm nitric oxide (NO) was decreased 6 h later, first to 15 ppm and then, as quickly as possible, to 3 ppm. The mean inhalation period was 51 h (6-131 h, SD +/- 42). The initial value of AaDO2 and OI decreased significantly within the first 6 h of INO (P < 0.001). After the first 6 h, 4 patients died: 1 with MAS of an extrapulmonary cause and 3 CDH patients because of pulmonary hypoplasia. In the remaining 11 patients the decrease in AaDO2 and OI during the first 24 h of INO was highly significant (P < 0.0001).

CONCLUSION

In a heterogeneous group of 15 newborns with severe respiratory insufficiency, the initial AaDO2 and OI decreased significantly within the first 6 h of INO.

Prenatal diagnosis of congenital diaphragmatic hernia and pulmonary hypoplasia and therapeutic strategy

The outcome of fetuses with congenital diaphragmatic hernia (CDH) has been reported to be fatal when pulmonary hypoplasia (PH) is severe. As an indicator of PH, we attempted to measure the lung-thorax transverse area ratio (L/T) using ultrasonic echography. Immediate postnatal surgery was performed using high-frequency oscillatory ventilation (HFOV) and sometimes followed by extracorporeal membrane oxygenation (ECMO). Eighteen fetuses were treated and 14 survived. L/T correlated well with the best preductal arterial blood gas data before surgical reduction during manual ventilation and HFOV, while preductal PO2 and alveolar-arterial oxygen differences from patients managed with HFOV were better than those in patients with manual ventilation. Although L/T also correlated with the duration of O2 therapy and hospitalization in survivors without major anomalies, there was no significant difference between L/T in survivors and nonsurvivors. Because delayed institution of ECMO and complications related to ECMO management seemed to be a major cause of death in non-survivors, the unsalvageable L/T due to PH was estimated to be below 0.06 for HFOV and below 0.1 for conventional ventilation based on the correlation between L/T and preductal P02. These results suggest that L/T is a useful indicator of PH in patients with CDH and also that HFOV is advantageous in treating CDH with PH. The advantage of prenatal diagnosis in predicting unsalvageable L/Ts, should be considered in the therapeutic strategy.

Simulation models in the planning of health care facilities: an application in the case of neonatal extracorporeal membrane oxygenation

OBJECTIVES

To investigate whether modelling techniques can be used in the planning of health care facilities for patients requiring neonatal extracorporeal membrane oxygenation (ECMO).

METHODS

In a micro-simulation model the number of patients that will have to be referred to facilities abroad is estimated for any number of neonatal ECMO patients presenting annually for treatment in The Netherlands, and any number of ECMO facilities. The inputs to the model consist of the number of ECMO facilities, the number of patients presenting annually, the duration of treatment and the date on which patients present for ECMO treatment. The model is estimated on data from The Netherlands for 1992, during which 29 patients were treated in three facilities. Several future scenarios are modelled, principally one in which a potential increase to 56 patients per year is foreseen.

RESULTS

The model indicates that, if such an increase takes place, no additional ECMO facilities will be necessary in The Netherlands if between three and four referrals annually to centres outside the region (or abroad) are considered acceptable and feasible. In that situation, it is expected that on 22 occasions each year two patients will be treated simultaneously, for a total of 81 days. On ten occasions, all three facilities will be occupied at the same time, for 21 days in total. On 199 days, at least one of the facilities will be occupied.

CONCLUSION

The current study shows that the acceptability and feasibility of patient referrals to ECMO centres abroad is an important issue which health care planners will have to consider. The study also shows that modelling techniques can provide information that is useful to policy-makers in the planning of health care facilities.

Entry criteria for extracorporeal membrane oxygenation In neonates with congenital diaphragmatic hernia treated with high-frequency oscillatory ventilation

Although respiratory management with high-frequency oscillatory ventilation (HFOV) has generally been used for neonates with congenital diaphragmatic hernia (CDH), entry criteria for extracorporeal membrane oxygenation (ECMO) based on data from patients who underwent HFOV have not yet been reported. To establish entry criteria for ECMO in such patients, we retrospectively studied 36 neonates with CDH treated by HFOV in our institutions between 1986 and 1994. From the admission records, preductal and postductal arterial blood gas data and HFOV ventilation conditions for 72 h after admission were extracted. Oxygenation index (01) and alveolar-arterial oxygen gradient (A-aD02) time interval combinations were calculated. Patients were divided into two groups: candidates for ECMO (n = 22) who underwent ECMO (n = 18) or died without ECMO (n = 4); and non-candidates (n = 14), who survived without ECMO. Blood gas data in patients placed on ECMO were comparable to those in patients who died without ECMO: mean pre- and postductal OI for 4 h > 30, postductal A-aD02 ≥620 mmHg for 4 h, postductal A-aD02 ≥580 mmHg for 8 h, and postductal A-aD02 ?550 mmHg for 12 h showed better sensitivity with a specificity of more than 90% compared to entry criteria that had previously been used in our institutions: a postductal OI >40 for 4 h and postductal A-aDO2 ≥610 mmHg for 8 h. In addition, a combination of preand postductal OI >30 for 4 h indicated a sensitivity of 95.5% and a specificity of 92.9%.

Evaluation of gas exchange, pulmonary compliance, and lung injury during total and partial liquid ventilation in the acute respiratory distress syndrome

OBJECTIVE

To investigate whether pulmonary compliance and gas exchange will be sustained during "total" perfluorocarbon liquid ventilation followed by "partial" perfluorocarbon liquid ventilation when compared with gas ventilation in the setting of the acute respiratory distress syndrome (ARDS).

STUDY DESIGN

A prospective, controlled, laboratory study.

SETTING

A university research laboratory.

SUBJECTS

Ten sheep, weighing 12.7 to 25.0 kg.

INTERVENTIONS

Lung injury was induced in ten young sheep, utilizing a right atrial injection of 0.07 mL/kg of oleic acid followed by saline pulmonary lavage. Bijugular venovenous extracorporeal life support access, a pulmonary artery catheter, and a carotid artery catheter were placed. When the alveolar-arterial O2 gradient was >/= 600 torr and PaO2 </= 50 torr (</= 6.7 kPa) with an FIO2 of 1.0, extracorporeal life support was instituted. For the first 30 mins on extracorporeal life support, all animals were ventilated with gas. Animals were then ventilated with equal tidal volumes of 15 mL/kg during gas ventilation (n=5) over the ensuing 2.5 hrs, or with total liquid ventilation for 1 hr, followed by partial liquid ventilation for 1.5 hrs (total/partial liquid ventilation, n=5).

MEASUREMENTS AND MAIN RESULTS

An increase in physiologic shunt (gas ventilation = 69 +/- 11%, total/partial liquid ventilation = 71 +/- 3%) and a decrease in static total pulmonary compliance measured at 20 mL/kg inflation volume (gas ventilation = O.48 +/- 0.03 mL/cm H2O/kg, total/partial liquid ventilation = 0.50 +/- 0.17 mL/cm H2O/kg) were observed in both groups with induction of lung injury. Physiologic shunt was significantly reduced during total and partial liquid ventilation when compared with physiologic shunt observed in the gas ventilation animals (gas ventilation = 93 +/- 8%, total liquid ventilation = 45 +/- 11%, p<.001; gas ventilation = 95 +/- 3%, partial liquid ventilation = 61 +/- 12%, p<.001), while static compliance was significantly increased in the total, but not the partial liquid ventilated animals when compared with the gas ventilated group (gas ventilation = 0.43 +/- 0.03 mL/cm H2O/kg, total liquid ventilation = 1.13 +/- 18 mL/cm H2O/kg, p <.001; gas ventilation = 0.41 +/- 0.02 mL/cm H2O/kg, partial liquid ventilation = 0.47 +/- 0.08, p = .151). In addition, the extracorporeal life support flow rate required to maintain adequate oxygenation was significantly lower in the total/partial liquid ventilation group when compared with that of the gas ventilation group (gas ventilation = 89 +/- 7 mL/kg/min, total liquid ventilation = 22 +/- 10 mL/kg/min, p <.001; gas ventilation = 91 +/- 12 mL/kg/min, partial liquid ventilation = 41 +/- 11 mL/kg/min, p < .001). Lung biopsy light microscopy demonstrated a marked reduction in alveolar hemorrhage, lung fluid accumulation, and inflammatory infiltration in the total/partial liquid ventilation animals when compared with the gas ventilation animals.

CONCLUSIONS

In a model of severe ARDS, pulmonary gas exchange is improved during total followed by partial liquid ventilation. Pulmonary compliance is improved during total, but not during partial liquid ventilation. Total followed by partial liquid ventilation was associated with a reduction in alveolar hemorrhage, pulmonary edema, and lung inflammatory infiltration.

Early versus late identification of infants at high risk of developing moderate to severe bronchopulmonary dysplasia

We developed a simple method to identify neonates at high risk of bronchopulmonary dysplasia (BPD) and determined whether early (8 hours) and late (14 days) risk assessment is equally useful. A retrospective cohort design was utilized of subjects enrolled in multi-dose surfactant trials to develop each risk identification model. Prospective testing of the late 14-day model was done to determine accuracy. The primary outcome variable (moderate to severe BPD) was defined as the need for oxygen and mechanical ventilation beyond 28 days of life and significant chest X-ray changes. Variables were screened for inclusion in the models by univariate and multiple regression analysis of data available at 14 days or 8 hours of life, converted to yes-no variables by the use of receiver-operator curves; the final model was based on those variables that gave the highest sensitivity and specificity for identifying BPD risk. Thirty-eight out of 116 of the 14-day model subjects developed BPD. The 14-day model (F1O2 > or = 0.30 and ventilation index (defined as 10,000/peak pressure x rate x PCO2) < 0.510 (or < 0.800 if previously septic)] had a sensitivity of 82% and specificity of 89%. It accurately identified 83% of cases (51/61) during at 1-year prospective test. The positive predictive value was 81% and negative predictive value 88%. Forty-four of the 698 early 8-hour model subjects developed BPD. The 8-hour model [gestational age < 31 weeks, 5-minute Apgar < 9, ventilator rate > 23 breaths/min, and ventilation index < 0.895] had a sensitivity of 73%, specificity of 83%, negative predictive value of 98% but positive predictive value of only 22%. These observation indicated that clinical data can create an accurate and simple model to classify infants into high- or low-risk groups for BPD. Using such models very early in life (e.g., at 8 hours) may lead to a high number of false-positive identifications.

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.

Massive transfusion in the neonate

The neonate who undergoes massive transfusion is at risk for transfusion-associated complications similar to the adult, but also faces some that are unique to the infant. By understanding the mechanics of the procedures that result in single or multiple blood volume exchange, the transfusion medicine physician can better assist his/her colleagues in the support of these patients.

Dose-response to inhaled nitric oxide in acute hypoxemic respiratory failure of newborn infants: a preliminary report

In acute hypoxemic respiratory failure of term and near-term neonates, extra- and intrapulmonary right-to-left shunting contribute to refractory hypoxemia. Inhaled nitric oxide (NO) decreases pulmonary arterial pressure and improves ventilation-perfusion mismatch in a variety of animal models and selected human patients. We report on 10 consecutive term and near-term newborns with severe acute hypoxemic respiratory failure due to diaphragmatic hernia, meconium aspiration syndrome, group B streptococcus sepsis, pneumonia or acute respiratory distress syndrome, who received increasing doses of inhaled NO (up to 80 ppm) to improve the arterial partial pressure of oxygen (PaO2). The response to NO and the optimum NO concentration which improved PaO2 varied considerably between patients. Improvement of PaO2 was absent or poor (less than 10 mm Hg) in the 4 newborns with meconium aspiration syndrome and in 1 patient with congenital diaphragmatic hernia, while in the other 5 patients inhaled NO increased the mean (+/- SE) PaO2 from 41 +/- 6 to 57 +/- 9 mm Hg (P < 0.05). Optimum NO concentrations determined by dose-response measurements performed during the first 8 hr of NO inhalation were 8-16 ppm except for 2 newborns with congenital diaphragmatic hernia who required 32 ppm to effectively increase PaO2. Four of the 5 patients in whom the PaO2 rose by more than 10 mm Hg received inhaled NO for extended periods of time (5 to 23 days) with no signs of tachyphylaxis. The optimum NO concentration dropped to less than 3 ppm after prolonged mechanical ventilation or when intravenous prostacyclin was given concomitantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Liquid ventilation improves pulmonary function, gas exchange, and lung injury in a model of respiratory failure

OBJECTIVE

The authors evaluated gas exchange, pulmonary function, and lung histology during perfluorocarbon liquid ventilation (LV) when compared with gas ventilation (GV) in the setting of severe respiratory failure.

BACKGROUND

The efficacy of LV in the setting of respiratory failure has been evaluated in premature animals with surfactant deficiency. However, very little work has been performed in evaluating the efficacy of LV in older animal models of the adult respiratory distress syndrome (ARDS).

METHODS

A stable model of lung injury was induced in 12 young sheep weighing 16.4 +/- 3.0 kg using right atrial injection of 0.07 mL/kg of oleic acid followed by saline pulmonary lavage and bijugular venovenous extracorporeal life support (ECLS). For the first 30 minutes on ECLS, all animals were ventilated with gas. Animals were then ventilated with either 15 mL/kg gas (GV, n = 6) or perflubron ([PFC], LV, n = 6) over the ensuing 2.5 hours. Subsequently, ECLS was discontinued in five of the GV animals and five of the LV animals, and GV or LV continued for 1 hour or until death.

MAIN FINDINGS

Physiologic shunt (Qps/Qt) was significantly reduced in the LV animals when compared with the GV animals (LV = 31 +/- 10%; GV = 93 +/- 4%; p < 0.001) after 3 hours of ECLS. At the same time point, pulmonary compliance (CT) was significantly increased in the LV group when compared with the GV group (LV = 1.04 +/- 0.19 mL/cm H2O/kg; GV = 0.41 +/- 0.02 mL/cm H2O/kg; p < 0.001). In addition, the ECLS flow rate required to maintain the PaO2 in the 50- to 80-mm Hg range was substantially and significantly lower in the LV group when compared with that of the GV group (LV = 14 +/- 5 mL/kg/min; GV = 87 +/- 15 mL/kg/min; p < 0.001). All of the GV animals died after discontinuation of ECLS, whereas all the LV animals demonstrated effective gas exchange without extracorporeal support for 1 hour (p < 0.01). Lung biopsy light microscopy demonstrated a marked reduction in alveolar hemorrhage, lung fluid accumulation, and inflammatory infiltration in the LV group when compared with the GV animals.

CONCLUSION

In a model of severe respiratory failure, LV improves pulmonary gas exchange and compliance with an associated reduction in alveolar hemorrhage, edema, and inflammatory infiltrate.

Extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation has now evolved into standard therapy for patients unresponsive to conventional ventilatory and pharmacological support. This article presents a clinical review of extracorporeal life support and its application to neonatal and pediatric patients as well as children requiring circulatory support after open heart surgery.

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.

High frequency oscillation for preterm infants with severe respiratory failure

High frequency oscillation (HFO) as rescue treatment for preterm infants with severe respiratory failure has been assessed and prognostic factors identified. Thirty six infants with a median gestational age of 27 weeks were studied. Immediately before transfer to HFO, the infants were receiving an inspired oxygen concentration of > or = 85% and/or a mean airway pressure of > or = 12 cm H2O and had a median alveolar-arterial oxygen gradient (A-aDO2) of 73.28 kPa (range 49.34-89.91). Seventeen infants subsequently died. Comparison of those 17 with the remaining 19 infants demonstrated that respiratory distress syndrome and persistent fetal circulation were associated with a significantly better outcome than pulmonary airleak. The A-aDO2 after two and six hours on HFO was significantly higher in those infants who survived compared with those who died. We conclude that a diagnosis of pulmonary airleak and failure to show early improvement in respiratory status indicate a poor prognosis when HFO is used as rescue treatment.

Extracorporeal membrane oxygenation. Will this therapy continue to be as efficacious in the future?

The efficacy of ECMO has been discussed. If only a dichotomous live/die outcome is used as a measure of utility, ECMO is efficacious for infants with a greater than 20% mortality rate. Using a Bayesian approach and neonatal follow-up data, one concludes that ECMO, as used at present, is effective. Future measures of efficacy will vary depending on utility measures used, the populations studied, and the relative efficacy of alternative therapies.

Do we use the right entry criteria for extracorporeal membrane oxygenation in congenital diaphragmatic hernia?

In a retrospective review we analysed alveolar-arterial oxygen difference (AaDO2) as an entry criterion for extracorporeal membrane oxygenation (ECMO) in neonates with several forms of acute respiratory insufficiency. Although for meconium aspiration syndrome, respiratory distress syndrome, sepsis, and idiopathic pulmonary hypertension of the newborn we found values in accordance with the literature, patients with congenital diaphragmatic hernia (CDH) met 80% mortality criteria with significant lower AaDO2 values. Several patients died before ever reaching usual entry criteria for ECMO, because serious lung deterioration makes AaDO2 values unreliable. Awaiting classical ECMO entry criteria for patients with CDH may at least partially explain the lower survival rate for ECMO in CDH.

Respiratory insufficiency as a cause of neonatal death (with aspects on the potential need for ECMO treatment)

In order to identify children with fatal outcome in a neonatal intensive care unit in which only outborns are admitted, a retrospective study over a 10-year period was undertaken. The study was limited to respiratory disorders. The aim of the study was to identify lethal risk factors and thereby the need for improving therapeutic tools. Diagnoses, perinatal history, ventilator settings, blood gases, medical treatment, X-ray findings, head ultrasounds, echocardiograms, laboratory tests, surgical procedures and autopsy findings were evaluated. Severe respiratory insufficiency requiring mechanical ventilation was found in 777 patients and of these babies, 207 (27%) died while still on the ventilator. Fifty-eight patients were excluded for various reasons and thus 149 patients were included in the study. It is concluded that the mortality rate from respiratory insufficiency in the material studied was consistently high over the 10-year period. New therapeutic modalities, one of which is ECMO, are offered nowadays in clinical practice and may improve mortality and morbidity rates.

Improved pulmonary outcome after exogenous surfactant therapy for respiratory failure in term infants requiring extracorporeal membrane oxygenation

A blinded, randomized, controlled study was designed to test whether multiple-dose surfactant therapy would improve pulmonary outcome in term infants with respiratory failure, resulting in a shortened period of extracorporeal membrane oxygenation (ECMO). Infants > or = 34 weeks of gestational age in severe respiratory failure and receiving ECMO were stratified by diagnosis and then randomly assigned to the treatment or the control group. Four doses of modified bovine lung surfactant extract (beractant) were administered to the surfactant group (n = 28), and an equal volume of air was administered to the control group (n = 28). Lung compliance was initially low in both groups; after treatment, values were higher with time in the surfactant group (F = 5.40, p = 0.026). The ECMO treatment period was significantly shorter in the surfactant group (mean +/- SD: 107 +/- 33 hours vs 139 +/- 54 hours for the control group; U = 232, p = 0.023). Tracheal aspirate concentrations of surfactant protein A were low in both groups, and then increased steadily to a higher level in the surfactant group (F = 2.58, p = 0.04). The overall incidence of complications after ECMO was decreased in the surfactant group (18% vs 46% for the control group; chi-square value = 5.004, p = 0.025). Radiographic scores, echocardiographic findings, incidence of intracranial or pulmonary hemorrhage and bronchopulmonary dysplasia, time to extubation, duration of oxygen therapy, and duration of hospitalization did not differ between the two groups. Beractant in this population improved pulmonary mechanics, increased surfactant protein A content in tracheal aspirate, decreased time on ECMO duration, and reduced disease complications.

Mortality and morbidity rates among lower birth weight infants (2000 to 2500 grams) treated with extracorporeal membrane oxygenation

To assess the validity of the currently accepted lower weight limit of 2 kg for treatment of neonates with extracorporeal membrane oxygenation (ECMO), we reviewed the outcome of lower birth weight (2.0 to 2.5 kg, n = 29) and higher birth weight (n = 235) for infants treated with venoarterial ECMO at our institution from 1984 through 1990. Newborn infants with congenital diaphragmatic hernia were not included. The mortality rate was significantly greater after venoarterial ECMO in lower than in higher birth weight infants (relative risk 3.45; confidence interval = (1.68, 5.79)). For infants with the diagnosis of respiratory distress syndrome, the mortality rate was 56% (5/9) for lower and 8% (2/25) for higher birth weight infants (p less than 0.01). The most frequent cause of death in lower birth weight infants was intracranial hemorrhage (7/10 deaths). The overall incidence of any neuroimaging abnormality was significantly greater for lower birth weight infants (p = 0.044), primarily because of the higher incidence of major intracranial hemorrhage. Finally, the risk of developmental delay (development quotient less than 70 at 1 to 2 years of age) among survivors available for follow-up was significantly higher among the lower than the higher birth weight infants. These outcome data suggest that further reduction of the current lower weight limit for ECMO should not become standard without prospective research or technologic advances.

Congenital diaphragmatic hernia in an era of delayed repair after medical and/or extracorporeal membrane oxygenation stabilization: a prognostic and management classification

In November 1987 we began to practice delayed repair of acutely symptomatic congenital diaphragmatic hernia (CDH) following medical and/or extracorporeal membrane oxygenation (ECMO) stabilization. We reviewed 23 consecutive patients with CDH symptomatic at birth treated over the ensuing 2 1/2 years. The mean age at admission, age at repair, and interval from admission to repair were 4.9, 37.0, and 32.6 hours, respectively. Overall survival was 52% (12/23). ECMO was used in 14 patients with 7 survivors (50%); 4 of these patients underwent repair prior to ECMO and 10 while on ECMO. The patients were retrospectively grouped into three classes based on postductal arterial blood gas (ABG) response to conventional medical management: class A (n = 8), able to achieve and sustain adequate oxygenation (PO2 greater than 60 mm Hg) and hyperventilation (PCO2 less than 40 mm Hg); class B (n = 10), unable to sustain adequate oxygenation (PO2 less than 60 mm Hg) but able to be hyperventilated (PCO2 less than 40 mm Hg); and class C (n = 5), unable to be oxygenated (PO2 less than 60 mm Hg) or hyperventilated (PCO2 greater than 40 mm Hg). The interval from admission to repair was 13.6, 53.5, and 25.4 hours for classes A, B, and C, respectively. Two class A (25%), nine class B (90%), and three class C patients (60%) were placed on ECMO. Survival rates were 88%, 50%, and 0% for classes A, B, and C, respectively. We propose the following management protocol. Class A patients are stable and can be repaired at any convenient point after admission without prerepair ECMO; few will need it afterward.(ABSTRACT TRUNCATED AT 250 WORDS)

Utility of serial EEGs in neonates during extracorporeal membrane oxygenation

We found electroencephalographic (EEG) studies to be useful for monitoring cerebral function, for confirming seizure activity, and for limited prediction of short-term outcome in 145 neonates who required extra-corporeal membrane oxygenation (ECMO) of reversible respiratory failure. The EEG tracings were classified as normal or as mildly, moderately, or markedly abnormal; abnormal recordings were further classified as focal, diffuse, or predominantly lateralized. A significant decrease in frequency and degree of EEG abnormalities was observed in recordings obtained after ECMO compared to those obtained prior to (P = .001) or during ECMO (P = .001). There was no significant increase in marked EEG abnormalities when recordings obtained before and during ECMO were compared (P = 0.41). Of 11 infants with electrographic seizures during ECMO, 7 (64%) either died during their nursery courses or were developmentally handicapped at age 1 year which is a significantly greater adverse outcome than that observed in infants without EEG seizure activity (P less than .003). No consistently lateralized EEG abnormalities were observed during or after ECMO when compared to tracings obtained before cannulation of the right common carotid artery. There was no acute change in EEG rhythm or amplitude over the right cerebral hemisphere during right common carotid artery cannulation. Our observations support the value of serial EEG in the assessment of cerebral function in critically ill infants undergoing ECMO. They further suggest that, in this patient population, cannulation of the right common carotid artery is a safe procedure that does not result in lateralized abnormalities of cerebral electrical activity.

Nursing diagnoses as guidelines in the care of the neonatal ECMO patient

The number of centers offering extracorporeal membrane oxygenation (ECMO) as a treatment for neonatal respiratory failure continues to grow. To ensure high-quality patient care and consistency among centers, nursing care guidelines should be established. A plan of care using nursing diagnoses as guidelines for the ECMO nurse is presented.