Extracorporeal membrane modality conversions.

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.

Alpha1-adrenergic receptor mRNA and inflammatory mediator expression in circulating leucocytes after cardiac surgery.

Vasodilation after coronary artery bypass surgery is a common complication. Inflammatory mediators influence the expression of alpha1-adrenergic receptors. Do patients requiring high doses of postoperative inotropic support have down-regulated alpha-adrenergic receptors? Is there a characteristic pattern of preoperative inflammatory mediator expression that could predict a complicated course after the operation? Forty-four patients undergoing cardiac bypass surgery with extracorporeal circulation were prospectively investigated. Five perioperative blood samples were taken (preoperative, two hours, 12 hours, 36 hours and 72 hours postoperative). The leucocyte mRNA-expression of the three alpha1-adrenergic receptor subtypes (A, B and D) and 11 different pro-inflammatory mediators were investigated with the real-time reverse transcriptase polymerase chain reaction. The patients were divided into three groups (No-noradrenaline [No-NA]= 0 microg/min, Low-noradrenaline [Low-NA]=0.1-7 microg/min, High-noradrenaline [High-NA] >7 microg/min), according to their postoperative noradrenaline requirements. Preoperatively, alpha1(A)-receptor expression was 4.9-fold (High-NA) and 18.7-fold (Low-NA) higher than the No-NA group (P=0.005) and plasma noradrenaline levels were higher in the High-NA group (P=0.005). Across all groups at 12 hours after the operation, alpha1(A) -receptor expression decreased to approximately one-fifth of preoperative levels (P=0.01); but with greater duration and magnitude of relative decrease in the High-NA group. Patients in the No-NA group had significant postoperative increases in leucocyte inflammatory mediator expression for IL-1beta, TLR4, TREM, MPO, MMP9 and TNF genes, whereas the changes in the Low-NA and High-NA groups were not significant. Low preoperative levels of noradrenaline and low expression of alpha1(A)-adrenoreceptors in leucocytes was associated with less probability of requiring noradrenaline support after cardiac surgery.