Extracorporeal membrane oxygenation (ECMO) in neonatal respiratory failure. 100 cases

Adenosine triphosphate: a potential therapy for hypoxic pulmonary hypertension

In this study we investigated whether a low-dose infusion of ATP-MgCl2 could ameliorate the pulmonary hypertension resulting from hypoxic pulmonary vasoconstriction. Three-week-old piglets were anesthetized, intubated, ventilated with room air, and cannulated for the measurement of pulmonary and systemic arterial pressure and pulmonary artery flow (cardiac output). The ventilator inflow was then changed to a mixture containing 10% oxygen, 4% CO2, and balance nitrogen. Serial infusions of ATP-MgCl2 at 0.1, 0.5 and 1.0 mg/kg/min were compared to preinfusion hypoxia baselines. Hypoxia alone produced a significant elevation in pulmonary artery pressure. Although all dose rates of ATP-MgCl2 produced a significant decrease (30%) in mean pulmonary artery pressure, we observed a maximum decrease in MPAP at the lowest rate of ATP infusion. Pulmonary artery flow rose slightly during ATP infusion; therefore, it was the change in pulmonary vascular resistance that accounted for the decrease in pulmonary artery pressure. In contrast, the systemic pressure was significantly decreased only during the 1.0 mg/kg/min infusion. The predominant pulmonary effects are a result of the virtual clearance of ATP-MgCl2 in a single pass through the circulation. Adenosine in the presence or absence of MgCl2 produced only a 10% reduction in mean pulmonary artery pressure, and MgCl2 had no effect when infused alone. From these results, we conclude that a low-dose infusion of ATP-MgCl2 could ameliorate the vasoconstriction associated with hypoxic pulmonary hypertension without significant deleterious systemic side effects.

Extracorporeal membrane oxygenation causes significant changes in intracranial pressure and carotid artery blood flow in newborn lambs

The effects of ECMO on cerebral dynamics, particularly in the face of asphyxia, are largely unknown. We inquired as to whether carotid artery blood flow (CABF) and intracranial pressure (ICP) were affected by carotid artery/jugular vein ligation, asphyxia, ECMO, and ECMO with asphyxia. Lightly sedated newborn lambs (two to four days old, 3 to 4 kg) in four groups were monitored for mean ICP by an epidural sensor, mean CABF by a flow probe, and mean arterial pressure. Mean values were determined for the duration of each step of the experiment. ECMO was venoarterial at 100 to 120 mL/kg/min. CABF and ICP were measured in group 1 before and after CA/JV ligation; in group 2 during normoxia/normocapnia followed by hypoxia (30 to 40 torr)/hypercapnia (70 to 90 torr); in group 3 before, during, after ECMO while normoxic/normocapnic throughout; and in group 4 as ECMO was begun while hypoxic/hypercapnic. Vessel ligation alone caused no significant CABF/ICP changes. Asphyxia caused physiologic increases in CABF (P less than .03) and ICP (P less than .01). ECMO alone caused a significant decrease in ICP (P less than .003). ECMO with asphyxia caused an even more severe decrease in ICP (P less than .001) combined with augmented CABF (P less than .03). The ICP decrease was limited to the duration of ECMO. Possible explanations include loss of cerebral autoregulation induced by hypoxia/hypercarbia and alterations in cerebral venous drainage necessitated by this method of cardiopulmonary bypass.

Stunned myocardium in an infant treated with extracorporeal membrane oxygenation

This report describes a case of postischemic myocardial dysfunction that was successfully treated with ECMO.

Clinical use of extracorporeal membrane oxygenation in the treatment of persistent pulmonary hypertension following surgical repair of congenital diaphragmatic hernia

The clinical use of extracorporeal membrane oxygenation (ECMO) in the treatment of persistent pulmonary hypertension following surgical repair of congenital diaphragmatic hernia is reported on 11 patients. The patients had a total of 13 treatments; two patients had two treatments. During the same period of clinical use, 122 patients were placed on ECMO for all causes. The indications, results, and complications of the use of ECMO for treatment following surgical repair of congenital diaphragmatic hernia are presented. The reversal of persistent pulmonary hypertension is demonstrated. All patients treated by ECMO for congenital diaphragmatic hernia have survived.

Postoperative cardiopulmonary failure in tetralogy of Fallot with absent pulmonary valve syndrome treated by extracorporeal membrane oxygenation

When tetralogy of Fallot with absent pulmonary valve syndrome leads to respiratory failure in early infancy, total repair has been advocated. Respiratory insufficiency may persist despite a surgically adequate repair. An infant with this syndrome underwent total surgical correction. Extracorporeal membrane oxygenation was employed in the early postoperative period for intractable pulmonary insufficiency and myocardial dysfunction.

Life-threatening intrathoracic complications during treatment with extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) has been successful (greater than 80% survival) in 35 centers in greater than 900 newborns with severe respiratory failure having an estimated mortality of greater than 80% on conventional management. During the last 3 years we have treated 79 newborns with 74 survivors (94%). Their diagnoses included meconium aspiration, persistent fetal circulation, respiratory distress syndrome, congenital diaphragmatic hernia, and sepsis. Seven patients (9%) had life-threatening intrathoracic complications requiring emergent intervention while on ECMO: tension hemothorax (3), tension pneumothorax (2), and pericardial tamponade (2). Pericardial tamponade and tension hemothorax and pneumothorax show a similar pathophysiology of increasing intrapericardial pressure and decreasing venous return. Perfusion is initially maintained by the nonpulsatile flow of the ECMO circuit before further decrease in venous return results in decreasing ECMO flow and progressive hemodynamic deterioration. Each of the seven patients demonstrated a clinical triad that includes increasing PaO2 and decreasing peripheral perfusion (as evidenced by decreasing pulse pressure and decreasing SvO2) followed by decreasing ECMO flow with progressive deterioration. The diagnoses were confirmed by transillumination, chest x-ray, or cardiac echocardiogram. Initial emergent placement of a percutaneous drainage catheter was temporizing in all seven cases. However, four patients required emergent thoracotomy for definitive treatment while still on ECMO. All seven patients were weaned from ECMO and are short-term survivors (6 months to 3.5 years). As use of ECMO for newborn severe respiratory failure increases, responsible physicians must be familiar with life-threatening intrathoracic complications and appropriate treatment strategies.

Right common carotid artery ligation in extracorporeal membrane oxygenation

The effect of right common carotid artery ligation required for arteriovenous extracorporeal membrane oxygenation (ECMO) was investigated in 35 infants. Their neonatal course was reviewed for evidence of right-sided ischemia of the brain, as suggested by the presence of focal seizures, hemiparesis, focal abnormalities on electroencephalography, or infarct or hemorrhage demonstrable on neuroimaging studies. A significant incidence of left focal seizures (9/35) versus right focal seizures (2/35) was noted, suggesting an effect of the carotid ligation on right hemisphere function. Computed tomographic scans (20/35 infants), electroencephalograms (18/35), ultrasound scans (31/35), and neurologic examinations did not reveal an increased incidence of right hemisphere abnormalities. These data suggest that systematic evaluation of the effects of right common carotid ligation should proceed as discussion continues on expanding the use of ECMO.

Selective use of extracorporeal membrane oxygenation in the management of congenital diaphragmatic hernia

Extracorporeal membrane oxygenation (ECMO) provides lung rest for moribund infants with congenital diaphragmatic hernia (CDH) after deterioration from a "honeymoon" period. This suggests that unstable pulmonary hypertension determines demise more than pulmonary hypoplasia. We avoided treating overwhelming pulmonary hypoplasia by using ECMO only if the premoribund condition had been marked by evidence of adequate lung parenchyma as a best preductal PO2 greater than 100 torr and PCO2 less than 50 torr with maximal therapy. Twenty-six CDH infants with respiratory distress within 4 hours survived operation. Five were not ECMO candidates, with best PO2 33 +/- 9, PCO2 157 +/- 30 torr, and died. Seven honeymoon infants, with best PO2 325 +/- 80, PCO2 27 +/- 5, survived without ECMO. Fourteen additional infants had honeymoon 26 +/- 13 hours with PO2 256 +/- 48, PCO2 30 +/- 8 followed by a-AdO2 gradients 600 torr x 16 +/- 4.5 hours despite maximal therapy. All 14 were treated with ECMO for 48 to 210 hours. Arterial blood gas values at initiation were PO2 34 +/- 6, PCO2 59 +/- 19, and pH 7.22 +/- 0.2. Right-to-left shunting due to pulmonary hypertension was documented by oximetry and two-dimensional echo/Doppler examination. Twelve of 14 (86%) ECMO-treated infants survived with normal arterial blood gas values on room air, no right-to-left shunting, and no gross neurologic sequellae to date. Two of 14 died. Improvement on ECMO was marked by positive hyperoxia response and decreased right-to-left shunting.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrasonographic findings (CNS, thorax, abdomen) in infants undergoing extracorporeal oxygenation therapy

Extracorporeal membrane oxygenation (ECMO) has been performed on 45 neonates at the Children's Hospital of Michigan in a 39-month period. Ultrasound evaluation of these patients prior to and during ECMO therapy has demonstrated abnormalities in the central nervous system including intracranial hemorrhage (21), extra-axial fluid collections (5), and ventricular enlargement (2). Ultrasonic evaluation of the thoracic cavity in 12 infants revealed pleural fluid in 8. There were seven children with varying types of peritoneal fluid. Two children had visceral abnormalities - 1 with liver hemorrhage and 1 with hydronephrosis found prior to ECMO. Most of these findings could not have been diagnosed without ultrasound and may lead directly to alterations in clinical management. Ultrasound is an extension of physical examination which is important in hour-by-hour clinical care of patients on ECMO.

Mortality with extracorporeal membrane oxygenation following repair of congenital diaphragmatic hernia in 93 infants

The results of extracorporeal membrane oxygenation (ECMO) following repair of congenital diaphragmatic hernia (CDH) are analyzed for 93 neonates reported to the Neonatal ECMO Registry. Each infant was symptomatic at birth and developed life-threatening hypoxemia after herniorrhaphy. ECMO was used after neonates met criteria predictive of death in individual centers. These included (1) failure of medical therapy to reverse hypoxemia (35 neonates); (2) acute clinical deterioration making death appear likely (37 neonates); (3) AaDO2 greater than 600 for 8 hours (13 neonates); (4) oxygen index score of 51 for 4.8 hours (5 neonates); and (5) cardiac arrest (1 neonate). With ECMO, 52 infants (58%) survived and were discharged. Pre-ECMO arterial blood gas analysis was not predictive of outcome. Mortality was higher in small premature infants. ECMO corrected the hypoxemia, which usually causes death following congenital diaphragmatic herniorrhaphy. Unfortunately, 47 major bleeding complications occurred with 29 deaths. Therefore, improved survival may depend on new methods designed to prevent bleeding.

Extracorporeal membrane oxygenation following repair of congenital diaphragmatic hernias

From 1981 through 1986, 8 newborns with congenital diaphragmatic hernia required herniorrhaphy in the first 8 hours of life. Extracorporeal membrane oxygenation (ECMO) was employed in 7 after they met local criteria predictive of 95% mortality. These criteria were an alveolar-postductal arterial oxygen gradient greater than 600 mm Hg for 12 hours or hemodynamic instability. Four of these 7 patients had unremitting hypoxemia after herniorrhaphy (no "honeymoon" period), 3 of whom survived. One additional patient died, producing a mortality of 29%. ECMO used for 68 to 241 hours (mean, 163 hours) provided reliable oxygenation in all. Deaths resulted from disseminated intravascular coagulation and bleeding, and bleeding and pulmonary failure after ligation of a patent ductus arteriosus. Complications occurred in 6 patients and included bleeding (3), hernia recurrence (3), and air embolism (1). Follow-up ranging from 1 year to 6 years after discharge of the 5 survivors shows normal growth and development in 4. The reported mortality without ECMO following congenital diaphragmatic herniorrhaphy in the first 8 hours of life ranges between 60 and 80%. While bleeding may present problems, survival of newborns with refractory hypoxemia after diaphragmatic repair has improved with ECMO.

Experience with renal failure during extracorporeal membrane oxygenation: treatment with continuous hemofiltration

We use extracorporeal membrane oxygenation (ECMO) to treat respiratory and cardiac failure in children who are unresponsive to standard ventilator and pharmacologic management. All patients have cardiac and abdominal ultrasonography prior to ECMO to identify major structural anomalies and anatomically normal kidneys. Despite this, oliguric renal failure is seen in a number of patients. Acute renal failure (ARF) developed in two of the first 20 patients we placed on ECMO and both of these patients died. Six of the last 27 patients (22%) also developed ARF and were treated with continuous hemofiltration (CH) placed in-line with the extracorporeal circuit. The technique of CH removes plasma water and dissolved solutes while retaining proteins and cellular components of the intravascular space. The duration of CH ranged from 9 to 112 hours (mean 57.5 hours). Indications for CH were hypervolemia, hyperkalemia, and azotemia. The mean serum potassium prior to CH was 5.6 (range 4.3 to 7.0) compared with 4.5 after filtration. We filtered 5 to 10 mL/kg/h and replaced it with crystalloid chosen on the basis of serum and filtrate electrolytes. These six patients had a 33% mean weight gain prior to CH. We were able to remove as much as 2,200 g in the most edematous patient with significant improvement in cardiopulmonary status. Four of the patients on CH died of their primary pulmonary or cardiac disease without specific problems related to ARF. The other two patients were successfully weaned from ECMO, extubated, and have not needed further therapy for renal failure. We conclude that CH is useful in managing the complications of oliguric renal failure during ECMO.

Extracorporeal membrane oxygenation in pediatric respiratory failure

ECMO is capable of safely supporting respiration and circulation in newborns with severe respiratory failure and a moribund clinical presentation. The results thus far suggest that term infants with respiratory failure are the best candidates for ECMO, with a survival rate of 83 per cent. Infants under 35 weeks' gestation have a very high incidence of intracranial hemorrhage. Consequently, we do not currently accept them for ECMO treatment. The outcome of the survivors is largely determined by the clinical condition before ECMO and by major complications. Research must be directed toward cost effectiveness, timing and earlier use, alternative vascular access, cannula and circuit design, and expanded indications.