Ch 28 (s28.8, Controversy 1)
Establishes the one replicated finding in this literature — microembolic signals are several times more common on venoarterial than venovenous support, consistent with arterial return delivering circuit-generated emboli directly into the systemic circulation — while finding no relationship to flow, anticoagulation intensity or 6-month neurological outcome.
Venovenous versus venoarterial configuration; correlation with extracorporeal flow rate, activated partial thromboplastin time, left ventricular ejection fraction; and 6-month Glasgow Outcome Scale
DOI 10.1111/aas.12736
Multigated transcranial Doppler detection and grading of microembolic signals, repeated during treatment
Single centre; 11 venoarterial patients only; no control of recording duration against outcome; the authors themselves conclude that multicentre studies with more extensive cases are required. Explicitly failed to reproduce an earlier six-patient report correlating signals with circuit flow over 4 L/min, and criticises that report's 15-minute recording and unspecified decibel threshold.
Signals detected in 26.2 percent of venovenous and 81.8 percent of venoarterial patients (p under 0.001); severe grading occurred only in the venoarterial group (5 of 11). No correlation with extracorporeal flow rates or activated partial thromboplastin time in either configuration. Inverse correlation between left ventricular ejection fraction and signal grading in venoarterial patients (p=0.037). No clinical neurological impairment correlated with signal detection at 6-month follow-up; 6-month survival 50 percent.
Monocentric prospective observational study at a regional ECMO referral centre, December 2013 to August 2015: 248 transcranial Doppler monitoring sessions in 42 venovenous and 11 venoarterial adult patients, plus 2 on extracorporeal carbon dioxide removal. Patients with bilateral inadequate temporal windows, right-to-left shunt or haemodynamic carotid stenosis excluded; all assessed by transoesophageal echocardiography.