Low-dose Adenosine-induced Transient Asystole During Intracranial Aneurysm Surgery

Background: Few studies have evaluated the adenosine dose that induces cardiac arrest during intracranial aneurysm surgery. We present our experiences with adenosine-induced transient asystole (AiTA) during intracranial aneurysm surgery and dosage recommendations.

Methods: We retrospectively reviewed the medical records of all patients who underwent intracranial aneurysm surgery between July 2016 and December 2018. Patients who experienced AiTA during intracranial aneurysm surgery were included in the study.

Results: Our study included nine intracranial aneurysm surgeries performed in eight patients. Thirteen episodes of AiTA were reported. Five of these were performed to facilitate bleeding control due to intraoperative aneurysm rupture (IAR), and adenosine doses were 9 mg (0.20 mg/kg), 12 mg (0.25 mg/kg), 12 mg (0.26 mg/kg), 18 mg (0.34 mg/kg), and 18 mg (0.39 mg/kg), resulted in transient asystole for 12, 14, 9, 44, and 18 s, respectively. For episodes without IAR, adenosine doses ranging from 6 to 18 mg (0.11-0.39 mg/kg) caused asystole for 8-33 s. In five episodes without IAR, low-dose adenosine (lower than 0.2 mg/kg) was used and caused asystole ranging from 8 to 12 s. Postoperatively, two patients had elevated cardiac troponin T levels but normal electrocardiograms.

Conclusion: AiTA can facilitate the clipping of intracranial aneurysms at low-risk of serious cardiac complications. An adenosine dose of 0.2-0.4 mg/kg is safe and effective in both IAR and non IAR situations. In non IAR cases, we propose that low-dose AiTA is an option to facilitate aneurysm clipping. A starting dose of 6 mg or 0.1-0.2 mg/kg can adequately induce brief asystole by softening the aneurysmal sac during clip application.