Successful use of extracorporeal membrane oxygenation to treat severe respiratory failure in a pediatric patient with a scald injury.

If ECMO is to be used effectively in pediatric patients, specifically in those with burns, the candidates must be chosen with care. Unlike the situation in neonates, when ECMO is being considered for use in a pediatric patient, no clear set of inclusion or exclusion criteria exists. Evaluation of a pediatric patient for ECMO support is largely based on an assessment of the patient's condition and a center's previous experience with pediatric ECMO. The data that are available through ELSO indicate that survival decreases as the number of days a patient receives mechanical ventilation before the initiation of ECMO increases. The effect of burns on patients' outcomes is unknown. Age, duration of mechanical ventilation, and excision with allografting or homografting of the burns should all be considered before the patient is offered ECMO support. The remaining prognostic signs--duration of ECMO support, frequency of complications, and blood product requirements--are available only after the ECMO course is under way or completed. The success of our center and others in using ECMO to treat respiratory failure associated with burns shows that some patients with burns may benefit from ECMO. Unfortunately, no specific set of criteria exists that would enable ECMO centers to differentiate good candidates from poor ones and thus be able to offer ECMO support with confidence in its benefit for the patient.

Anticoagulation practices during neonatal extracorporeal membrane oxygenation: survey results.

To ascertain current anticoagulation management during neonatal extracorporeal membrane oxygenation (ECMO), a telephone survey was undertaken of all active ECMO (n = 81, 100% response rate) centres in the USA. Hospital policies regarding federal regulations governing laboratory tests [Clinical Laboratory Improvement Amendment (CLIA) 1988] were determined along with specific patient anticoagulation strategies and use of specific activated coagulation time (ACT) equipment. More than 90% of the respondents use the Hemochron device (International Technidyne Corp, Edison, NJ, USA) while the remaining centres use the Hemotec device (Medtronic Hemotec, Inc, Englewood, CO, USA). Quality control (QC) testing is performed by most centres, but there is no consensus regarding frequency of testing nor methods for dealing with abnormal results. Nearly one-half of the centres use beef lung-derived heparin and the other half use porcine intestinal-derived heparin. One-half of the programmes had a minimum heparin dose despite the ACT value, but the range varied significantly. Four out of five respondents reported that heparin dosages were dictated strictly by ACT results, and 63% will temporarily stop heparin administration for high ACT results, bleeding and/or surgery. Approximately one-third of the centres perform proficiency testing of the equipment in compliance with CLIA 1988. In conclusion, there appears to be no consensus regarding commitment to a QC programme among active ECMO centres.

Intracorporeal CO2 removal and permissive hypercapnia to reduce airway pressure in acute respiratory failure. The theoretical basis for permissive hypercapnia with IVOX.

Initial studies have shown that the intravascular oxygenator and carbon dioxide removal device (IVOX, Cardiopulmonics, Inc., Salt Lake City, UT) removes approximately 30% of VCO2. After noting increased CO2 removal with increased venous CO2, we developed a conceptual analytical model based on data obtained from patients and laboratory experiments. Increasing the CO2 gradient across the hollow fiber membranes of IVOX increases the operating efficiency of the device. Using the patient management technique of permissive hypercapnia (limiting tidal volumes, respiratory rates, and airway pressures) serves to increase the CO2 gradient across the membrane. The conceptual analytical model predicts that a PaCO2 of 75-80 mm Hg is required to obtain a CO2 gradient that results in IVOX CO2 removal of approximately 90-100 ml CO2/min. This technique may allow a broader application of both permissive hypercapnia and IVOX in acute respiratory failure.

Devices and monitoring during neonatal ECMO: survey results.

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