Extracorporeal membrane modality conversions

Abstract

We report the case of a patient with cardiovascular and respiratory failure due to severe anaphylaxis requiring multiple extracorporeal membrane oxygenation (ECMO) cannulation strategies to provide adequate oxygen delivery and ventilatory support during a period of rapid physiological change. ECMO provides partial or complete support of oxygenation-ventilation and circulation. The choice of which ECMO modality to use is governed by anatomical (vessel size, cardiovascular anatomy and previous surgeries) and physiological (respiratory and/or cardiac failure) factors. The urgency with which ECMO needs to be implemented (emergency cardiopulmonary resuscitation (eCPR), urgent, elective) and the institutional experience will also influence the type of ECMO provided. Here we describe a 12-year-old schoolgirl who, having been resuscitated with peripheral veno-venous (VV) ECMO for severe hypoxemia due to status asthmaticus in the setting of acute anaphylaxis, required escalation to peripheral veno-arterial (VA) ECMO for precipitous cardiovascular deterioration. Insufficient oxygen delivery for adequate cellular metabolic function and possible cerebral hypoxia due to significant differential hypoxia necessitated ECMO modification. After six days of central (transthoracic) VA ECMO support and 21 days of intensive care unit (ICU) care, she made a complete recovery with no neurological sequelae. The use of ECMO support warrants careful consideration of the interplay of a patient's pathophysiology and extracorporeal circuit dynamics. Particular emphasis should be placed on the potential for mismatch between cardiovascular and respiratory support as well as the need to meet metabolic demands through adequate cerebral, coronary and systemic oxygenation. Cannulation strategies occasionally require alteration to meet and anticipate the patient's evolving needs.

Choosing the appropriate configuration and cannulation strategies for extracorporeal membrane oxygenation: the potential dynamic process of organ support and importance of hybrid modes

“…If the indication for ECMO is primarily progressive hypoxemia or hypercapnia despite optimal conventional mechanical ventilation and respiratory care, V‐V cannulation is the method of choice. V‐A ECMO provides direct circulatory and respiratory support but is associated with a higher complication rate and poorer outcomes in some settings. On the other hand, V‐V ECMO principally functions as an artificial lung with no direct circulatory support.…”

“…Patient physiology or clinical conditions and needs, may change over time (e.g. the heart may recover faster than the lungs) and modifications in ECMO configuration mat be occasionally necessary. The conversion from the initial ECMO strategy to a different modality should always be strongly considered if the patient's perfusion is inadequate or other goals of therapy are not being met, or if complications are arising as a result of the cannulation strategy, e.g.…”

“…differential hypoxemia. The need to convert to a different ECMO modality should not necessarily be considered as a planning failure, but rather as a response to a patient's dynamic condition.…”

Unexpectedly Good Neurological Outcome after Prolonged Cardiac Arrest

“…There have been few reports about switching VA-ECMO to VV-ECMO for respiratory disorder after ECPR [6]. In our case, there remained severe respiratory disorder from volume overload, lung contusion, alveolar hemorrhage and pulmonary atelectasis after recovering from severe shock, and we could improve…”

Rapid Deployment ECMO

“…Additional indications for ECPR other than cardiac disease include poisoning [66,67], blunt chest trauma [68,69], electrolyte disturbances [70], hypothermia [26•, 27, 71], and anaphylaxis [72]. Extrapolating clear guidelines on the basis of these brief reports is difficult, and candidacy for ECPR must be established on a caseby-case basis.…”