# Different low activated clotting time target anticoagulation protocols for patients during extracorporeal membrane oxygenation management: a retrospective cohort study

## TL;DR

This study compares different anticoagulation targets during ECMO and finds that lower clotting times do not increase risks of complications.

## Contribution

The study provides evidence that low ACT targets during ECMO are as safe as higher targets regarding oxygenator changes and bleeding.

## Key findings

- No significant difference in oxygenator change rates across low, medium, and high ACT groups.
- Bleeding and thromboembolic event rates were similar among all ACT groups.
- Low ACT protocols do not increase risks during ECMO management.

## Abstract

Anticoagulation management is crucial for patients to prevent serious complications during extracorporeal membrane oxygenation (ECMO). However, the optimal target for low activated clotting time (ACT) anticoagulation during ECMO remains unclear.

A retrospective cohort study was conducted, including patients who received ECMO support in the Second Affiliated Hospital of Harbin Medical University in China from April 2017 to May 2024. Eligible patients were categorized into low (<160 s), medium (160–180 s), and high (>180 s) ACT groups. Major outcomes included ECMO oxygenator change, bleeding and thromboembolic events.

A total of 148 patients were included after applying the exclusion criteria and divided into the low ACT group (n = 25, 16.9%), the medium ACT group (n = 86, 58.1%), and the high ACT group (n = 37, 25.0%). The baseline characteristics were not significantly different among the three groups. The oxygenator change rate did not show a statistically significant difference (low ACT group: 0.0%; medium ACT group: 8.1%; high ACT group: 8.1%; χ2 = 1.96, p = 0.39). There was no significant difference in the proportion of bleeding events among the low (n = 3, 12.0%), medium (n = 15, 17.4%), and high (n = 9, 24.3%) ACT groups (χ2 = 1.61, p = 0.45). The incidence of thromboembolic events showed no significant difference among the low (n = 4, 16.0%), medium (n = 16, 18.6%), and high (n = 9, 24.3%) ACT groups (χ2 = 0.78, p = 0.68).

Different low ACT target anticoagulation protocols for patients during ECMO do not increase the risk of oxygenator change, bleeding and thromboembolism during ECMO management. These results can help clinicians choose appropriate ACT target anticoagulation for patients. Further prospective trials are needed to verify the low ACT target anticoagulation protocols.

Chinese Clinical Trial Registry, ChiCTR2500100151, Registered 3 April, 2025.

Different target anticoagulation protocols for ECMO management are compared. The study groups are categorized by activated clotting time (ACT): Low ACT (<160s), Medium ACT (160s-180s), High ACT (>180s). Patient distribution: VV ECMO (69.6%), VA ECMO (28.4%), VAV ECMO (2.0%). Oxygenator changes, bleeding, and thromboembolic events are analyzed for each group, with no significant differences observed. Key findings emphasize that low ACT does not increase risks during ECMO and clinicians can choose appropriate protocols. Further trials are recommended.