Flow-Dependent Transient Asystole During Rapid Pneumoperitoneum Establishment Via 8-mm Trocar

Transient bradycardia and asystole are recognized complications of insufflation during laparoscopic surgery due to acute peritoneal stretch triggering vagal mediated reflexes. This reaction has been attributed primarily to elevated intraabdominal pressure (IAP) with less attention given to the potential role of carbon dioxide (CO₂) flow rate, access modality, and port diameter. Here, we report the case of a 34-year-old male undergoing a robotic cholecystectomy due to gallstone hepatitis. After initial abdominal access was obtained using a Veress needle, pneumoperitoneum was established at a target pressure of 15 mmHg through an 8-mm trocar at a flow rate of 40 L/minute. Upon transition to trocar insufflation, the patient developed transient asystole at the time of insufflation lasting approximately 2-3 seconds, followed by sinus bradycardia. Insufflation was immediately discontinued, and glycopyrrolate and ephedrine were administered in response. The patient's heart rate returned to his baseline shortly after deflation with the entire episode lasting less than 1 minute. Pneumoperitoneum was then re-established at a lower flow rate and pressure without recurrence of bradyarrhythmia. Although the target pressure was within standard operative guidelines, the high initial flow rate and large initial trocar size may have distended the peritoneum to a greater extent quicker, thus inducing a larger vagal response. The immediate onset, rapid reversibility with deflation, and absence of recurrence following slower insufflation support a rate-dependent stretch mechanism rather than the effect of absolute IAP alone.