Initiation Of Extracorporeal Life Support Research Articles

Experience with Extracorporeal Life Support in Pediatric Patients after Cardiac Surgery

Extracorporeal life support (ECLS) had been successfully used in neonatal respiratory failure, but cardiac ECLS has been used increasingly in recent years. The purpose of this study was to review our experience in pediatric patients supported by ECLS for postoperative circulatory failure and to analyze the factors associated with mortality. Between January 1999 and December 2004, 68 pediatric patients (< 18 years old) who received ECLS within 7 days after cardiac surgery at the National Taiwan University Hospital were included in this study. The overall survival rate of this cohort was 32.4%. Age and gender did not affect survival. Patients with separate biventricular physiology had a higher probability of survival than those with systemic-pulmonary shunt or cavopulmonary anastomosis (41.3% vs. 13.6%, p < 0.05). Acute renal failure during ECLS was significantly associated with mortality (83% vs. 33.5%, p < 0.001). After ECLS initiation, the lowest lactate levels on the second to fourth days were lower in survivors than in nonsurvivors (2.4 vs. 3.3 mmol/L, p < 0.05). There was a trend toward a better survival in the most recent 2 years in comparison with the previous 4 years (47.6% vs. 25.5%, p = 0.07), although this trend did not reach statistical significance. In conclusion, nonbiventricular physiology, acute renal failure, and high blood lactate levels after ECLS increased the risk of mortality for pediatric patients requiring ECLS for postoperative cardiac support.

Outcome of pediatric patients treated with extracorporeal life support after cardiac surgery

Background Extracorporeal life support (ECLS) has been used for over two decades in select patients after cardiac surgery. We previously described factors associated with death in this population. We now review our recent experience to reassess factors related to mortality. Methods All pediatric patients who received ECLS support within 7 days after surgery between July 1995 and June 2001 were examined to describe clinical features associated with survival. We compared the results with our prior report to assess changes in practice and outcome. Results Seventy-four patients were followed. Fifty percent survived to discharge. Hospital survival was not significantly related to patient age, cannulation site, or indication. Thirty-five percent of patients required hemofiltration while on ECLS and were significantly less likely to survive (23% vs 65%). A multivariate analysis combining all children from our prior report with the present cohort revealed that patients who received hemofiltration were five times more likely to die (odds ratio 5.01, 95% confidence interval 2.11–11.88). Children with an adequate two-ventricular repair had lower risk of death (odds ratio 0.42, 95% confidence interval 0.19–0.91) after adjusting for patient age, study period, and hours elapsed before initiation of ECLS after surgery. Conclusions Patients with an adequate two-ventricle repair have significantly higher hospital survival, whereas those with single ventricle physiology or need for dialysis have decreased survival.

Hypercalcemia associated with extracorporeal life support in neonates

Background/Purpose: Disturbances in calcium homeostasis are common at initiation of extracorporeal life support (ECLS). At the authors' institution many neonates undergoing ECLS have developed hypercalcemia. To determine the frequency of hypercalcemia in neonates during ECLS we performed retrospective chart review of neonates that required ECLS at our neonatal intensive care unit. Methods: The authors identified 76 consecutive neonates who underwent ECLS before 10 days of age at Cincinnati Children's Hospital Medical Center from July 1, 1991 to June 30, 1996. The hospital charts and ELSO forms were reviewed. Demographic, clinical, and laboratory data for each of the patients were reviewed, both before initiation and during ECLS. Hypercalcemia was defined as total serum calcium concentration of greater than 11 mg/dL (2.74 mmol/L) on at least one occasion beyond the first 24 hours of ECLS. Results: The hospital charts and ELSO forms from 70 patients were available for review. One patient was excluded because he was only on ECLS for 33 hours, and there were no calcium levels obtained after 24 hours of ECLS and until death. Twenty-five (36%) neonates undergoing ECLS had hypercalcemia (serum Ca > 11 mg/dL [2.74 mmol/L]). Hypercalcemia was associated with longer duration of ECLS (hypercalcemia group, 243 ± 115 hours and normocalcemia group, 139 ± 64 hours) and greater requirements for platelet transfusions (hypercalcemia group, 538 ± 282 mL and normocalcemia group, 372 ± 233 mL). This could not be explained by differences in primary diagnosis, amounts of calcium administered, and acid-base status. Conclusions: Hypercalcemia was found to be common in neonates that require ECLS and is associated with longer duration of ECLS support. Conservative calcium administration for neonates while on ECLS may be warranted. J Pediatr Surg 36:493-497. Copyright © 2001 by W.B. Saunders Company.

Is there a role for extracorporeal life support after stage I Norwood?

Controversy still surrounds the use of extracorporeal life support (ECLS) in patients with single ventricle physiology. An analysis of the experience with a group of neonates who underwent stage I Norwood palliation and received ECLS is reported. A retrospective review of hospital records, operative notes and perfusion data was performed in a group of 12 consecutive patients undergoing ECLS in the perioperative period after stage I. An analysis to identify risk factors for poor outcome was performed. The mean age and weight were 3.9 days (1-14) and 2.6 kg (1.4-3.8), respectively. There were 3/12 patients under 2.5 kg and four patients were under 35 weeks of gestation. The most common diagnosis (7/12) was hypoplastic left heart syndrome with aortic atresia. Associated extracardiac anomalies were present in four patients. Three patients had an additional cardiac defect and two of these required an additional surgical procedure besides the stage I Norwood. The mean circulatory arrest was 56 min (46-63). ECLS was initiated preoperatively in one, intraoperatively in nine, and postoperatively in two patients. The indication for support was: arrhythmia (one), low output (six), cardiac arrest (three), unbalanced circulation (one), and hypoxemia (two). The mean duration of support was 68 h (24-192). Eight patients were weaned off support, and six were discharged home in good condition. Morbidity included sepsis in five, renal failure in five, neurologic sequelae in three, and bleeding in two. Prematurity, renal dysfunction and the initiation of ECLS outside the operating room were significantly associated with poor outcome. Residual hemodynamic effect, low birth weight and neurologic event showed a tendency towards poor outcome, but did not reach statistical significance. Although the use of ECLS in patients with single ventricle physiology still carries a significant risk, prompt initiation of support can improve the outcome in a group of patients with impaired cardiopulmonary function after stage I palliation.

The use of extracorporeal life support in adult patients with primary cardiac failure as a bridge to implantable left ventricular assist device

Background. Extracorporeal life support (ECLS) is an effective technique for providing emergent circulatory assistance, and may represent a life-saving option in patients who might not initially be considered a candidate for other forms of circulatory support (extracorporeal or implantable left ventricular assist device [LVAD]). In the setting of cardiac arrest, ECLS represents the only viable method of initiating circulatory support. However, ECLS has a number of disadvantages that include high complication rates (eg, stroke, bleeding) and a limited duration of potential support, which have prevented its widespread acceptance, particularly in the adult population. With the increased successful application of long-term implantable LVADs as a bridge to transplant, the major limitation of ECLS could be overcome by bridging patients to a long-term implantable LVAD (“bridge to bridge”), thereby reducing the reluctance to utilize ECLS when indicated. After acquisition of the HeartMate LVAD (Thermo Cardiosystems, Inc, Woburn, MA) we investigated the use of ECLS as a bridge to an implantable LVAD and subsequent transplantation in selected high-risk patients. Methods and Results. From Oct 1, 1996 to Sept 30, 2000, 33 adult patients presenting with cardiac arrest or severe hemodynamic instability were placed on ECLS for the bridge to bridge indication. Of the 33 patients, 10 patients survived to LVAD implant, 1 was bridged directly to transplant, 5 weaned from ECLS, and 16 died on ECLS. Overall, 12 patients survived to discharge. One-year actuarial survival from the initiation of ECLS was 36%. One-year actuarial survival from the time of LVAD implant, conditional on surviving ECLS, was 80%. Conclusions. The 1-year survival of adult patients placed on ECLS and who subsequently survived to an implantable LVAD was favorable. These data support a strategy of ECLS to implantable LVAD bridge to heart transplant in adult patients who are in need of circulatory support and who are not initially candidates for other forms of mechanical support. The favorable results of this strategy support utilization of ECLS even in situations where myocardial recovery is thought to be unlikely.

Mortality is directly related to the duration of mechanical ventilation before the initiation of extracorporeal life support for severe respiratory failure.

To investigate the relationship between the period of mechanical ventilation before extracorporeal life support and survival in patients with respiratory failure. Retrospective review. Surgical intensive care unit at a university medical center. Thirty-six consecutive adult patients with severe respiratory failure managed with extracorporeal life support. Extracorporeal life support was utilized in 36 acute respiratory failure adult patients with a variety of diagnoses and an estimated mortality rate of > 90%. Management protocols were followed before and during extracorporeal life support. The 36 patients were physiologically similar before extracorporeal life support was initiated: shunt of 48 +/- 17%; F10(2) of 1.0 +/- 0.1; peak inspiratory pressure of 56 +/- 16 cm H2O; positive end-expiratory pressure of 14 +/- 6 cm H2O; and respiratory rate of 23 +/- 10 breaths/ min. Ventilation was utilized for 1 to 17 days before extracorporeal life support. Typical lung rest settings during extracorporeal life support were F10(2) of 0.40, peak inspiratory pressure of 30 cm H2O, positive end-expiratory pressure of 10 cm H2O, and respiratory rate of 6 breaths/min. Death was almost always secondary to end-stage pulmonary failure. Survival (hospital discharge) in these 36 patients was inversely associated with the number of days of preextracorporeal life support ventilation, with a 50% mortality rate predicted by logistic regression after 5 days of mechanical ventilation. The overall survival rate was 18 (50.0%) of 36 patients. In severe acute respiratory failure treated with lung rest and extracorporeal life support, a predicted 50% mortality rate was associated with 5 days of preextracorporeal life support mechanical ventilation.

Timing of intracranial hemorrhage during extracorporeal life support.

This study was conducted to determine the timing of intracranial hemorrhage (ICH) in patients on extracorporeal life support (ECLS) to improve the use of the head ultrasound in the detection of ICH. A review was conducted of all neonatal ECLS patients at the neonatal intensive care nursery at Kosair Children's Hospital in Louisville, Kentucky, from May, 1985 through November, 1994 to establish a study group of infants in whom an ICH developed while on ECLS. Thirty infants who had an ICH (excluding subarachnoid hemorrhage and infarction) on ECLS were included in the study. Data were collected that included patients demographics, age at initiation of ECLS, duration of ECLS, type of ECLS support (venoarterial or venovenous), oxygenation index and last arterial blood gas before ECLS, hours of ECLS before ICH, and grade of ICH. ICH occurred in 9.9% of the neonatal patients requiring ECLS. These included 8 infants with a Grade I bleed, 1 infant with a Grade II, 4 infants with a Grade III, and 17 infants with a Grade IV. Ten of the 30 patients had sepsis as their primary diagnosis, and these infants were more likely to have an ICH while on ECLS compared to nonseptic infants (p < 0.02). The Kaplan-Meier curve showed that 50% of ICHs occurred in the first 24 hours of ECLS, 75% by 48 hours, and that 85% of ICHs occurred within 72 hours of initiation of bypass. There was no difference in timing of ICH in the septic infants compared to the nonseptic infants. The late occurring bleeds (> 72 hours) were all associated with significant neurologic changes or with multiorgan failure. It is concluded that daily head ultrasounds should be performed during the first 3 days of ECLS because most ICHs (85%) occur in the first 72 hours of cardiopulmonary bypass. In this era of cost containment, subsequent head ultrasounds should be obtained with changes in the infant's neurologic status or with the development of multiorgan failure.

Improvement of Gas Exchange, Pulmonary Function, and Lung Injury With Partial Liquid Ventilation: A Study Model in a Setting of Severe Respiratory Failure

To evaluate gas exchange, pulmonary function, and lung histology during gas ventilation of the perfluorocarbon-filled lung compared with gas ventilation of the gas-filled lung in severe respiratory failure. Application of gas (GV) or partial liquid (PLV) ventilation in lung-injured sheep. A research laboratory at a university medical center. Eleven sheep 17.1 +/- 1.8 kg in weight. Lung injury was induced by intravenous administration of 0.07 mL/kg oleic acid followed by saline pulmonary lavage. When alveolar-arterial oxygen pressure difference (P[A-a]O2) was 600 mm Hg or more and PaO2 was 50 mm Hg or less with fraction of inspired oxygen of 1.0, bijugular venovenous extracorporeal life support (ECLS) was instituted. For the first 30 min on ECLS, all animals were ventilated with gas. Over the ensuing 2.5 h, ventilation with 15 mL/kg gas was continued without intervention in the control group (GV, n = 6) or with the addition of 35 mL/kg of perflubron (PLV, n = 5). At 3 h after initiation of ECLS, Qps/Qt was significantly reduced in the PLV animals when compared with the GV animals (PLV = 41 +/- 13%; GV = 93 +/- 4%; p < 0.005). At the same time point, pulmonary compliance was increased in the PLV when compared with the GV group (PLV = 0.61 +/- 0.14 mL/cm H2O/kg; GV = 0.41 +/- 0.02 mL/cm H2O/kg; p < 0.005). The ECLS flow rate required to maintain the PaO2 in the 50 to 80 mm Hg range was substantially and significantly lower in the PLV group when compared with that of the GV group (PLV = 25 +/- 20 mL/kg/min; GV = 87 +/- 15 mL/kg/min; p < 0.001). Light microscopy performed on lung biopsy specimens demonstrated a marked reduction in lung injury in the liquid ventilated (LV) when compared with the GV animals. In a model of severe respiratory failure, PLV improves pulmonary gas exchange and pulmonary function and is associated with a reduction in pulmonary pathology.

Emergency and long-term extracorporeal life support following acute myocardial infarction: Rescue from severe cardiogenic shock related to stunned myocardium: Clin. Cardiol. 1994; 17/10: 552–557

There has been no report regarding therapy of extracorporeal life support (ECLS) that showed stunned myocardium echocardiographically and electrocardiographically in patients with acute myocardial infarction. ECLS was performed in eight patients with cardiogenic shock or arrest unresponsive to catecholamines and intra-aortic balloon pumping following myocardial infarction; these patients required prolonged external cardiac massage. After the initiation of ECLS, both blood pressure and metabolic acidosis improved in all patients. Four of eight patients were weaned from ECLS after a mean of 69.3 h, which was far longer than previously reported in patients with ischemic heart disease. Three of these patients survived, and cardiac function recovered to NYHA class II in two of the survivors and class III in the other. The other five patients did not recover from coma during ECLS and died. A marked improvement of ventricular wall motion was seen in two survivors with the disappearance of pathologic Q waves after the initiation of ECLS. No occlusion of the coronary arteries or bypass grafts was observed in any of the survivors. These findings suggested the existence of stunned myocardium with myocardial reperfusion. The recovery of stunned myocardium may be delayed for days or even weeks, hence the extended period of ECLS therapy was theoretically justifiable. We conclude that long-term ECLS is a useful therapeutic method for patients with severe cardiogenic shock that is related to stunned myocardium.

Emergency and long‐term extracorporeal life support following acute myocardial infarction: Rescue from severe cardiogenic shock related to stunned myocardium

There has been no report regarding therapy of extracorporeal life support (ECLS) that showed stunned myocardium echocardiographically and electrocardiographically in patients with acute myocardial infarction. ECLS was performed in eight patients with cardiogenic shock or arrest unresponsive to catecholamines and intra-aortic balloon pumping following myocardial infarction; these patients required prolonged external cardiac massage. After the initiation of ECLS, both blood pressure and metabolic acidosis improved in all patients. Four of eight patients were weaned from ECLS after a mean of 69.3 h, which was far longer than previously reported in patients with ischemic heart disease. Three of these patients survived, and cardiac function recovered to NYHA class II in two of the survivors and class III in the other. The other five patients did not recover from coma during ECLS and died. A marked improvement of ventricular wall motion was seen in two survivors with the disappearance of pathologic Q waves after the initiation of ECLS. No occlusion of the coronary arteries or bypass grafts was observed in any of the survivors. These findings suggested the existence of stunned myocardium with myocardial reperfusion. The recovery of stunned myocardium may be delayed for days or even weeks, hence the extended period of ECLS therapy was theoretically justifiable. We conclude that long-term ECLS is a useful therapeutic method for patients with severe cardiogenic shock that is related to stunned myocardium.

Femoral veno-arterial extracorporcal life support with minimal or no heparin

Recent technological advances in cardiopulmonary bypass circuits achieving surface bonding with heparin have permitted prolonged extracorporeal life support (ECLS) in experimental studies without the use of systemic anticoagulation. Excessive bleeding and the need for massive transfusions after extended ECLS with systemic heparinization have often led to the development of sepsis and multisystem organ failure. The Carmeda bioactive surface circuit, along with a Bio-Medicus centrifugal pump (Bio-Pump) and the femoral veno-arterial route, were used successfully in 3 patients requiring ECLS between April 1992 and December 1992. In 2 patients the need for ECLS was acute allograft dysfunction after orthotopic cardiac transplantation with no evidence of cellular rejection. Both patients were receiving multiple inotropes and intraaortic balloon counterpulsation; their condition continued to deteriorate rapidly before the initiation of ECLS. The third patient failed to be weaned from cardiopulmonary bypass after myocardial rcvascularization for ischemic cardiomyopathy. Time on ECLS ranged from 57 to 128 hours. No systemic anticoagulation was used. One patient received no heparin, and the other 2 patients received intermittent heparin infusion to maintain an average activated clotting time of 195 and 214 seconds. Multisystem organ dysfunction present before initiation of ECLS was rapidly reversed, and all patients were weaned successfully without any immediate major complications. The ability to conduct prolonged ECLS without systemic anticoagulation and without repeat sternotomy opens new avenues for the use of this procedure in profound heart failure.

Extracorporeal life support for patients undergoing prolonged external cardiac massage

From November 1987 to February 1992, extracorporeal life support (ECLS) was used for four patients undergoing prolonged external cardiac massage following cardiac arrest. Their underlying diseases consisted of acute pulmonary embolism, pulmonary arterial thrombosis due to protein C deficiency, acute inferior left ventricular infarction accompanied by right ventricular infarction and thoracic contusion. After the initiation of ECLS, hemodynamic variables and metabolic acidosis improved in all of the cases. The case of pulmonary embolism and the case of acute myocardial infarction were successfully weaned from ECLS without complications. They were later discharged ambulatory from the hospital. The patient with pulmonary arterial thrombosis, who was comatose, became alert after the initiation of ECLS. However the patient finally died due to diffuse and massive pulmonary arterial thrombosis, which was probably related to protein C deficiency. The patient with thoracic contusion was also comatose before ECLS. He did not recover from the coma and died soon after the disconnection of ECLS. The latter two cases were suspected to have had irreversible organ failures not responsive to mechanical support of both circulation and respiration. We conclude that ECLS is a very useful method for patients requiring prolonged cardiac massage following cardiac arrest.