Single injection of lidocaine to reduce tourniquet hypertension in ambulatory arthroscopic patients under general anaesthesia: randomized, double-blind, placebo-controlled clinical trial.

BACKGROUND: This prospective study investigated whether a single dose of intravenous lidocaine could alleviate tourniquet hypertension in patients undergoing ambulatory arthroscopy under general anaesthesia.

METHODS: Patients aged 18-65 years undergoing knee arthroscopy under general anaesthesia were randomly divided into the lidocaine group (L group) and the normal saline group (N group). Patients received an intravenous injection 10 min before tourniquet inflation of either 1.5mg/kg lignocaine made up to 10ml with 0.9 per cent normal saline, or 10ml of 0.9 per cent normal saline. The primary outcome was the incidence of tourniquet hypertension. Secondary outcomes included haemodynamic changes, degree of elevation of blood pressure, changes in serum inflammatory indicators including interleukin 6 and tumour necrosis factor-α, the numerical rating scale, 15-item quality of recovery after surgery, the incidence of adverse events and the duration of hospital stay. Randomization was computer-generated with allocation concealment by sealed envelopes. Patients, caregivers and researchers were all blind to the allocation group throughout the study.

RESULTS: Ninety-six patients were included in the study; 48 in each group. Compared with the N group, the incidence of tourniquet hypertension in the L group was significantly lower (37.5 per cent versus 68.8 per cent; P < 0.002). The degree of elevation of systolic blood pressure from baseline to the end of surgery in the L group was significantly lower than the N group (17.1 per cent versus 23.6 per cent; P = 0.020). The concentration of tumour necrosis factor-α in the L group 5 min after tourniquet deflation was lower than in the N group (32.12 pg/ml versus 39.89 pg/ml; P = 0.029). The median numerical rating scale of the L group was significantly lower at 6 h (0 versus 3.0; P = 0.003) and 24 h (0 versus 2.0; P < 0.001) after surgery. In the L group, the total 15-item quality of recovery was significantly increased (131 versus 128; P = 0.017).

CONCLUSION: Single injection of intravenous lidocaine alleviated tourniquet hypertension in ambulatory arthroscopic patients under general anaesthesia. Intravenous lidocaine can inhibit tourniquet hypertension formation by reducing tumour necrosis factor-α release, and has beneficial effects on postoperative pain and recovery.

REGISTRATION NUMBER: ChiCTR2200055551 (https://www.chictr.org.cn/edit.aspx? pid=148235&htm=4).