Extracorporeal membrane oxygenation - An anesthesiologist′s perspective - Part II: Clinical and technical consideration

Abstract

Although the concept of extracorporeal membrane oxygenation (ECMO) has remained unchanged, component technology has evolved considerably over the past three decades. Presently the clinical conditions requiring ECMO support have been updated with input from the outcome data of patient registries. Modern circuit configuration has become less cumbersome, safer, and more efficient. Technological advances now allow prolonged support with fewer complications compared to the past eras and facilitate transition to a single bedside caregiver model, similar to hemofiltration or ventricular-assist devices. The clinical considerations and indicators for placing the patient on ECMO, the various circuit configurations, clinical and technical issues, and management aspects are considered in this article.

Veno-Venous Extracorporeal Membrane Oxygenation: Anesthetic Management for Massive Intracranial Hemorrhage in H1N1 Infection

“…Conversely, a SpO 2 of 90% may not be adequate for an anemic patient. While many clinicians are comfortable tolerating anemia during VV ECMO, some authors recommend maintaining the hematocrit is kept around 40% while others cite a goal of >5% above normal [12] [13]. When deciding to transfuse the anesthesiologist must weigh the benefits of improved oxygen delivery with the risks of the transfusion [12].…”

“…Volume of distribution, protein binding, physico-chemical characteristics and physiologic changes all influence how particular medications will be influenced by the ECMO circuit [14]. There is significant sequestration of propofol, opioids and benzodiazepines in the circuit [13]. Greater than 50% reductions in concentrations of midazolam, lorazepam, and fentanyl have been shown during ECMO, while morphine does not seem to be affected [15].…”

Anesthetic management including extracorporeal membrane oxygenation therapy of liver transplant recipient with life-threatening hypoxemia -a case report-

“…With ECMO flows of 2-3 L/min/m 2 , and assuming normal values of cardiac output and oxygen consumption, SaO 2 values of 85-95% can be achieved in the absence of any pulmonary ventilation [10]. Lung protective ventilation is essential for lung recovery during ECMO [11]. We successfully provided lung protective ventilation during ECMO support (Table 1).…”

“…Before cannulation, 75-150 IU/kg of heparin needs to be administered to acquire activated clotting time (ACT) over 300 second. During ECMO support, heparin must be infused continuously to maintain ACT 180 to 240 second [11]. However, the target ACT should be decreased if the patients have a tendency towards bleeding.…”

“…In other words, if adequate gas exchange is maintained on conventional ventilator support and the patient tolerates the reduced ECMO flow, a trial period without ECMO can be started [11]. With regards to VV ECMO, the actual ECMO flows do not need to be altered to assess native respiratory function-this is done by altering gas flow through the ECMO circuit.…”