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

Extracorporeal membrane oxygenation (ECMO) was used in the treatment of 100 newborn infants with respiratory failure in three phases: Phase I (50 moribund patients to determine safety, efficacy, and risks); Phase II (30 high risk patients to compare ECMO to conventional ventilation); and Phase III (20 moderate to high risk patients, the current protocol). Seventy-two patients survived including 54% in Phase I, 90% in Phase II, and 90% in Phase III. The major complication was intracranial bleeding, which occurred in 89% of premature infants (less than 35 weeks) and 15% of full-term infants. Best survival results were in persistent fetal circulation (10, 10 survived), followed by congenital diaphragmatic hernia (9, 7 survived), meconium aspiration (44, 37 survived), respiratory distress syndrome (26, 13 survived), and sepsis (8, 3 survived). There were seven late deaths; in follow-up, 63% are normal or near normal, 17% had moderate to severe central nervous system dysfunction, and 8% had severe pulmonary dysfunction. ECMO is now used in several neonatal centers as the treatment of choice for full-term infants with respiratory failure that is unresponsive to conventional management. The success of this technique establishes prolonged extracorporeal circulation as a definitive means of treatment in reversible vital organ failure.     

Studies on ECMO. (III)--Study on pumpless A-V ECMO

Silicon hollow fiber membrane oxygenator is considered to be useful for long term extracorporeal membrane oxygenation (ECMO) and blood usually flows inside of the fiber (inside flow type). But if it flows outside of the fiber (outside flow type), the pressure drop is supposed to be less than that of inside flow type. In this study the oxygenator of an outside flow type was used. At first, the pilot study was done to evaluate the capability of this oxygenator as an outside flow type. The pressure drop was 50 mmHg at the blood flow of 400 ml.min-1. At this blood flow and same gas flow, CO2 transfer rate was 22.3 ml.min-1. In the second study, the effects of pumpless arterio-venous ECMO (pumpless A-V ECMO) were studied in 8 dogs under mechanical hypoventilation. During ECMO, there were no significant changes in hemodynamics when the blood flow rate was 15% of cardiac output. PaO2 and PaCO2 recovered considerably. In conclusion, pumpless A-V ECMO using this membrane oxygenator of outside flow type is effective for CO2 removal and considered to be clinically useful.     

Anaesthetic mortality rates in Western Australia 1980-2002

The Western Australian Anaesthetic Mortality Committee has collected data since 1980. During this time, reporting of anaesthesia mortality has been mandatory in Western Australia, confidentiality and legal protection have been ensured, consistent definitions and classifications have been used, and reasonable estimates have been available for the number of surgical procedures performed. The data indicate that there was a decrease in anaesthesia-related mortality in the mid 1980s. Since then the rates have been relatively stable, in relation to both population and number of surgical procedures performed. At present, the rates are extremely low (< 1:50, 000 surgical procedures per annum), and similar to rates reported from other Australian states. While these figures are encouraging, their main function is to serve as the baseline for further improvements.     

North American neonatal extracorporeal membrane oxygenation (ECMO) devices: 2002 survey results

In mid 2002, surveys of active extracorporeal membrane oxygenation (ECMO) centers in the United States and Canada were conducted via E-mail regarding neonatal equipment and personnel. Seventy-four out of 99 (75%) North American ECMO centers listed in the Extracorporeal Life Support Organization (ELSO) directory responded to the survey. Of the responding centers, 95% use roller pumps, and the remaining 5% use centrifugal pumps. Silicone membrane oxygenators were used by 97% of the respondents, while 3% used hollow fiber oxygenators. Of the silicone membrane oxygenator users, 82% used the Medtronic ECMOtherm heat exchanger, 15% used a Gish heat exchanger, and 3% used the Dideco D720 heat exchanger. Sixty-one percent of the responding centers used some form of in-line blood gas monitoring. Five percent of the centers used a bubble trap in the arterial line, and 12% used an arterial line filter. A bladder was used by 92% of the centers, and 29% used a mechanical bladder box for servo regulation, the remaining 71% used pressure servo regulation. An air bubble detector was used by 65% of the responding centers, although 81% had the device available. Heparin coating was used by 5% of the centers on all their neonatal ECMO patients. The average low range ACT was 183 seconds, and the average high range ACT was 216 seconds. At 49% of the responding centers, perfusionists were involved with the ECMO program, registered nurses were involved at 84% of the centers, and respiratory therapists were involved at 61% of the centers, perfusion assistants were involved at one center (1%), and biomedical engineers were involved at one of the centers. When compared to a 1990 survey, a shift away from using bladder boxes and toward using air bubble detectors is apparent. But other than those two shifts, ECMO is done in much the same manner as it was done 12 years ago.     

Open lung biopsy in neonatal and paediatric patients referred for extracorporeal membrane oxygenation (ECMO)

BACKGROUND: This study was undertaken to determine the usefulness, safety, and most appropriate timing of open lung biopsy in infants and children considered for and on extracorporeal membrane oxygenation (ECMO) for respiratory failure. METHODS: A retrospective review of children referred for consideration of and placed on ECMO in our institution in the period 1996-2002. RESULTS: 506 patients were referred, 15 (3%) of whom underwent antemortem open lung biopsy (eight neonatal, four paediatric, and three cardiac patients). In the neonatal group open lung biopsy contributed to clinical decision making in all patients. Four neonates had a fatal lung dysplasia (three alveolar capillary dysplasia and one surfactant protein B deficiency) and treatment was withdrawn. Of the other four neonates, two had pulmonary hypoplasia, one had pulmonary lymphangiectasia, and one had meconium aspiration with mild barotrauma. Treatment was continued in these four patients and two survived. In the paediatric group the biopsies were of clinical relevance in two infants with pertussis who had lung infarction on biopsy in whom treatment was withdrawn. In the other two paediatric patients the biopsies were equivocal, treatment was continued, but both patients died. In the cardiac group, who presented perioperatively with pulmonary hypertension, the biopsies excluded a fatal lung dysplasia and severe pulmonary vascular disease but all three infants died. One patient had non-fatal bleeding complications. CONCLUSION: Open lung biopsy is clinically most useful when performed to diagnose fatal lung dysplasias in neonates and to confirm the presence of viable lung tissue in patients with acute lung injury due to pertussis infection.     

Prostate cancer mortality trends in Mexico, 1980-1995

BACKGROUND: In Mexico, prostate cancer (PC) is the second highest cause of mortality by cancer in men. In 1991, there were 2,473 deaths, with a crude rate of 5.66 cases per 100,000 men age 40 or over. For this same year, the ratio of proportional mortality to the total number of malignant tumors was 12.6%. Our objectives were to determine the trends and geographic distribution of mortality for PC in Mexico for 1980-1995. METHODS: Crude and adjusted mortality rates were carried out for 1980-1995. A test for trend was done using the simple lineal regression method. The standardized mortality ratio (SMR) was calculated for 1980-1995 for each Mexican state. RESULTS: The total number of deaths by PC in Mexico for 1980-1995 was 32,349. The crude mortality rate increased during that period from 3.16 to 6.75 cases per 100,000 men over age 40. The statistical trend test with respect to time was significant (P<0.0001). The state of Southern Baja California showed a higher SMR, and a smaller SMR was shown for the state of Quintana Roo. CONCLUSIONS: The mortality trends for PC increased for the period studied. It represents a serious problem for public health. We find that the central and northern states of the country, characterized by a greater industrial and socioeconomic development, are those with a higher SMR.     

Hematological abnormalities in neonatal patients treated with extracorporeal membrane oxygenation (ECMO).

The physical process of extracorporeal membrane oxygenation (ECMO) results in derangement of the hemostatic mechanism, which may lead to increased morbidity, secondary to the disease process. The purpose of this study was to evaluate the hematological status of neonates undergoing ECMO therapy, and to evaluate coagulation tests in predicting hemorrhagic risk. Following Institutional Review Board approval, 30 patients undergoing ECMO treatment were retrospectively entered into this study. Medical records were reviewed and indicators of hemostasis, transfusion, morbidity, and outcomes recorded. Assessment of coagulation was determined through serial analysis of platelet count, fibrinogen concentration, prothrombin time (PT), activated partial thromboplastin time (aPTT), antithrombin III, fibrin split products, D-dimers, plasma free hemoglobin, activated clotting time, ionized calcium, and thrombelastography (TEG). Median total transfusion requirements for all patients were 1.79 ml/kg/ECMO hr. Fifty-seven percent of the 30 patients were diagnosed as coagulopathic according to Extracorporeal Life Support Organization standards. Patients were separated into either a hemorrhagic group (HEM, > 2.0 ml/kg/ECMO hr, n = 13) or a nonhemorrhagic group (N-HEM, n = 17), with HEM patients requiring twice the transfusion volume of N-HEM (p < 0.0001). Hemorrhagic complications were reported in 53.8% of the HEM patients vs. 35.3% in the N-HEM group. HEM patients were transfused with significantly greater quantities of platelets on days 1, 3, 5, and 8 and packed red blood cells on day 7 when compared to N-HEM (p < 0.05). TEG determination showed significant differences between groups on days 3 and 6 (p < 0.005), and 8 (p < 0.05). Derangements in hemostasis resulting from ECMO are profound, with methods of assessing coagulation complicated by both the variability in patient condition and lack of specificity of laboratory tests. Interpretation of TEG data has shown to be a valuable supplement for managing this challenging patient population.     

Reversal of mortality for congenital diaphragmatic hernia with ECMO.

Extracorporeal Membrane Oxygenation (ECMO) has been available to neonates with respiratory failure at the University of Michigan School of Medicine since June 1981. In order to evaluate the impact of this type of pulmonary support, a retrospective analysis of 50 neonates with posterolateral congenital diaphragmatic hernia (CDH) who were symptomatic during the first hour of life and were treated between June 1974 and December 1987 was carried out. The patients were divided into two groups, those treated before June 1981 (16 patients) and those treated after June 1981 (34 patients). Overall survival improved from 50% (eight of 16 patients) during the pre-ECMO era to 76% (26 of 34 patients) during the post-ECMO period (p = 0.06). During the period after June 1981, 21 neonates were unresponsive to conventional therapy and were therefore considered for ECMO. Failure of conventional therapy was defined as acute clinical deterioration with an expected mortality of greater than 80% based on an objective formula previously reported. Six patients were excluded on the basis of specific contraindications to ECMO. Thirteen of 15 infants (87%) supported with ECMO survived. Three patients treated before 1981 met criteria for ECMO; all three died while receiving treatment using conventional therapy. These survival differences are significant (p less than 0.01). In addition, the survival of 87% for the infants treated with ECMO versus the expected mortality of greater than 80% for these same patients when treated with conventional therapy is highly significant (p less than 0.005). Based on this data, ECMO appears to be a successful, reliable, and safe method of respiratory support for selected, critically ill infants with CDH.     

Beyond survival: Readmissions and late mortality in pediatric ECMO survivors

IntroductionThe objective of our study was to identify rates of readmission and late mortality in pediatric extracorporeal membrane oxygenation (ECMO) patients after discharge from their ECMO hospitalization.MethodsWe conducted a population-based retrospective cohort study of children who were discharged after ECMO. Data were obtained from the State Inpatient Databases for 10 states. Time-to-event analyses were used to estimate the risk of readmission and to identify factors predictive of readmission and late mortality, including characteristics of initial hospital course and ECMO center volume.ResultsA total of 1603 pediatric ECMO patients were identified, and 42.4% of these patients died prior to discharge. Of the 924 ECMO survivors, 35.6% had an unplanned readmission, and 3% died during readmission within 1 year. The risk of readmission was significantly related to the indication for ECMO, number of complex chronic conditions, transfer status, and discharge destination (all p < 0.05). The risk of late mortality was significantly related to health insurance, transfer status, number of complex chronic conditions, and indication for ECMO (all p < 0.05).ConclusionsPediatric ECMO survivors have a high risk of hospital readmission with approximately 3% mortality during readmissions within 1 year of initial discharge.Type of StudyRetrospective Cohort StudyLevel of EvidenceLevel III     

Early CDH repair on ECMO: Improved survival but no decrease in ECMO duration (A CDH Study Group Investigation)

Purpose“Early on-ECMO” repair of CDH entails repair within 48–72 h of cannulation in an effort to optimize pulmonary physiology, shorten ECMO duration, and, ultimately, improve survival. This study evaluated the effect of early on-ECMO repair as compared to leaving patients unrepaired during ECMO.MethodsThe CDH Study Group database was queried for CDH patients requiring ECMO who either underwent repair within the first 72 h after cannulation or remained unrepaired on ECMO. Primary outcomes were survival to decannulation and ECMO duration.ResultsA total of 248 patients underwent early repair and 922 remained unrepaired on ECMO. The early repair group had increased risk factors for poor outcomes, including higher odds of cardiac defects and thoracic liver location, and lower odds of hernia sac presence. Nonetheless, ECMO survival for the early repair group was 87.1% compared to 78.4% in the unrepaired group (p = 0.002). However, the early repair group had a longer median ECMO duration than the unrepaired group (240.6 vs 196.8 h, p = 0.001).ConclusionWhile early ECMO repair does not shorten ECMO duration, it results in increased survival to decannulation as compared to those unrepaired on ECMO. This suggests that there may be a physiologic benefit leading to increased ECMO survival in a subset of patients undergoing on-ECMO repair over those designated to undergo post-ECMO repair.Level of evidenceLevel III.     

Comparison of four stainless steel heat exchangers for neonatal ECMO applications

Conventional neonatal extracorporeal membrane oxygenation (ECMO) circuits utilize a heat exchanger distal to the oxygenator to replace ambient heat loss and maintain patient normothermia. A secondary function of the ECMO heat exchanger is to act as an arterial line bubble trap to protect the patient against accidental air embolism. Using an asanguinous recirculating test circuit, we measured and compared heat transfer properties, pressure drop, air trapping capabilities, and priming characteristics of four commercially available stainless steel heat exchangers currently being used in neonatal ECMO circuits: Avecor ECMOtherm, Gish HE-3, Gish HE-4, and Electromedics D1079. Manufacturers' product specifications were also compared. The pressure drop across all four heat exchangers was less than 10 mmHg with flow rates up to 500 ml/min. The Gish HE-3 and HE-4 were the easiest to prime and de-air, while the Electromedics D1079 was the most difficult. The heat exchangers with integral bubble traps (D1079 and HE-4) have superior air trapping capabilities. The ECMOtherm provided moderate air trapping capabilities ( greater than 7.3 ml +/- 1.5 ml) at flow rates under 300 ml/min. The low prime HE-3 was the poorest at trapping air; less than 1 ml at a 400 ml/min pump flow rate. Thermal analysis indicated that the D1079 had the highest performance factor, though all four heat exchangers had similar heat transfer rates and were capable of warming perfusate from 34 degrees to 37 degrees C on a single pass at pump flow rates of 500 ml/min.(ABSTRACT TRUNCATED AT 250 WORDS)