Gas embolism during hysteroscopic surgery using bipolar or monopolar diathermia: a randomized controlled trial

OBJECTIVE: The objective of the study was to determine the incidence and amount of gas embolism during hysteroscopic surgery using either monopolar or bipolar diathermia and to investigate the relationship between the severity of gas embolism and the amount of intravasation of distension fluid. STUDY DESIGN: This was a randomized, observer-blinded trial. Fifty patients, scheduled for hysteroscopic surgery, were assigned to either monopolar or bipolar diathermia. Transesophageal echocardiography was used to detect and classify gas embolism (grade 0-IV). Intravasation of distension fluid was measured. RESULTS: Venous gas embolism was observed in all but 1 patient. A higher incidence of more extensive (grade IV) was seen during bipolar diathermia (42% vs 13%; P = .031). Paradoxical embolism was observed in 2 patients. When intravasation exceeded 1000 mL, significantly more grade IV venous gas embolism was seen (P = .049). CONCLUSION: During hysteroscopic surgery, gas embolism was equally observed irrespective of the type of diathermia. However, more extensive embolism was observed when intravasation of distension fluid exceeded 1 L. These results question the acceptance of up to 2500 mL intravasation of distension fluid if bipolar diathermia is used.