Switch from venoarterial extracorporeal membrane oxygenation to arteriovenous pumpless extracorporeal lung assist

Extracorporeal membrane oxygenation is an effective rescue tool to treat cardiopulmonary failure. Pumpless systems treat lung failure only; they require adequate cardiac output.

We report on 18 patients initially provided with venoarterial extracorporeal membrane oxygenation and then downgraded to a pumpless arteriovenous shunt with a membrane oxygenator by removal of the pump from the circuit after hemodynamic stabilization in the face of persisting pulmonary failure. Main underlying diseases were adult respiratory distress syndrome (44%) and pneumonia (28%). Mean patient age was 44 years, and mean body mass index was 25.7 kg/m(2). Anticoagulation, hemodynamic, and respiratory variables were analyzed.

All patients exhibited severe cardiopulmonary failure with a mean oxygenation ratio (partial pressure of oxygen to fraction of inspired oxygen ratio) of 74 +/- 43 mm Hg (mean partial pressure of oxygen, 70 +/- 33 mm Hg) and a mean partial pressure of carbon dioxide of 68 +/- 32 mm Hg despite maximal (ventilatory) conservative therapy (fraction of inspired oxygen, 0.98 +/- 0.08). Initial serum lactate was 51 +/- 43 mg/dL. The sequential organ failure assessment score averaged 11.8 +/- 2.47, and the lung injury score was 3.1 +/- 0.58. Total mechanical respiratory support was performed for a mean of 13.6 +/- 15.7 days. After 24 hours an improvement in oxygenation and a decrease in carbon dioxide was achieved with a mean partial pressure of carbon dioxide of 40 +/- 11 mm Hg (p < 0.001) and a partial pressure of oxygen of 86 +/- 26 mm Hg (p = 0.031). After 6 +/- 3 days of extracorporeal membrane oxygenation, patients were hemodynamically stabilized. Extracorporeal membrane oxygenation was downgraded to pumpless extracorporeal lung assist for another 10 +/- 15 days (range, 2 to 71 days). Twelve patients (66.7%) could be weaned, with a 30-day mortality of 55.6%. Norepinephrine dosage could be reduced significantly within 24 hours (3.2 +/- 1.8 versus 1.5 +/- 1.5 mg/h; p = 0.008).

Respiratory support by an extracorporeal device used as last resort therapy allows rapid stabilization of patients with acute lung failure. Early replacement of extracorporeal membrane oxygenation by pumpless extracorporeal lung assist minimizes the negative side effects of extracorporeal circulation.