Haemodynamic stability after paracervical block: A randomized, controlled, double-blind study comparing bupivacaine-adrenaline with bupivacaine.

Background: Paracervical block is widely used in gynaecological interventions on cervix and uterus. Many surgeons add adrenaline 100 μg or pitressin 3-5 IU in a total volume of 10-20 mL to reduce total blood loss. We wanted to examine haemodynamic stability in healthy patients given bupivacaine with and without adrenaline.

Methods: In this randomised, double-blinded, controlled study, 30 healthy women scheduled for cervical conisation got a paracervical block using bupivacaine 50 mg with adrenaline 100 μg (BA-group, n = 14) or without adrenaline (B-group, n = 16) after induction of general anaesthesia. LiDCOplus was used for minimally invasive haemodynamic monitoring. Changes in cardiac output (CO) and systolic blood pressure (SBP) were the primary outcome. Changes in heart rate (HR), stroke volume (SV), and systemic vascular resistance (SVR) were secondary outcome variables. Area under the curve (AUC) ratios and change from baseline to maximal values were used as effect measures comparing the two groups.

Results: The AUC-ratio for CO and SBP was 2.50 (P < 0.001) and 1.70 (P = 0.03), respectively. For HR, SV, and SVR the AUC-ratio was 1.59 (P < 0.01), 1.52 (P < 0.001), and 0.90 (P = 0.14), respectively. CO increased 68% (standard deviation (SD) 42%, P < 0.001), HR increased 41% (SD 26%, P < 0.001), and SV increased 26% (SD 17%, P < 0.001) from baseline to maximal values after 70-90 seconds in the BA-group.

Conclusion: Paracervical block with bupivacaine 50 mg and adrenaline 100 μg may give haemodynamic instability in healthy females and is not recommended if haemodynamic side effects are to be avoided.