Ankle‐brachial index to monitor limb perfusion in patients with femoral venoarterial extracorporeal membrane oxygenation

Background Limb ischemia is a major complication of femoral venoarterial extracorporeal membrane oxygenation (VA‐ECMO). Use of ankle‐brachial index (ABI) to monitor limb perfusion in VA‐ECMO has not been described. We report our experience monitoring femoral VA‐ECMO patients with serial ABI and the relationships between ABI and near infrared spectroscopy (NIRS). Methods This is a retrospective single‐center review of consecutive adult patients placed on femoral VA‐ECMO between January 2019 and October 2019. Data were collected on patients with paired ABI and NIRS values. Relationships between NIRS and ABI of the cannulated (E‐NIRS and E‐ABI) and non‐cannulated legs (N‐NIRS and N‐ABI) along with the difference between legs (d‐NIRS and d‐ABI) were determined using Pearson correlation. Results Overall, 22 patients (mean age 56.5 ± 14.0 years, 72.7% male) were assessed with 295 E‐ABI and E‐NIRS measurements, and 273 N‐ABI and N‐NIRS measurements. Mean duration of ECMO support was 129.8 ± 78.3 h. ECMO‐mortality was 13.6% and in‐hospital mortality was 45.5%. N‐ABI and N‐NIRS were significantly higher than their ECMO counterparts (ABI mean difference 0.16, 95% confidence interval [CI]: 0.13–0.19, p