Does Adding Lidocaine to Intrathecal Bupivacaine Affect Hemodynamic Parameters during Hip Fracture Surgery?

Background: Hip fracture is one of the most common problems in elderly that needs surgical repair. As, the majority of these patients have chronic diseases, they are at increased risk of peri-operative mortality and morbidity. The purpose of this study was to evaluate spinal anesthesia with bupivacaine vs bupivacaine in combination with lidocaine in terms of hemodynamic changes in patients undergoing hip fracture surgery.

Methods: This double-blind clinical trial was conducted on 292 patients undergoing surgery for hip fracture under spinal anesthesia. Patients were allocated into two groups of B (10 mg of hyperbaric 0.5% Bupivacaine) and BL (5 mg hyperbaric Bupivacaine 0.5% plus 50 mg Lidocaine 5%). Sensory and motor block and hemodynamic changes were consecutively measured before spinal anesthesia (T0), immediately after spinal injection (T1), every 5 minutes for half an hour (T2- T7), and at 45 minutes (T8) and 60 minutes (T9) after injection.

Results: Patients in the two groups were homogeneous in demographic characteristics including age, sex, BMI, ASA Class, baseline blood pressure and heart rate. The onsets of sensory and motor blocks in group BL were faster than group B ( P=0.0001 ). Also, the durations of sensory and motor blocks in group B were significantly longer than group BL (P=0.0001 ). The BL group had a significantly lower systolic blood pressure in all periods ( P<0.05 ). Although the heart rate in the BL group was lower than group B at all time points, this difference was only significant during T2-T3 ( P=0.033 and P=0.0001 , respectively). Group BL had significantly more episodes of hypotension, bradycardia, nausea and vomiting ( P=0.0001 , P=0.023 , P=0.003 , and P=0.033 , respectively).

Conclusion: According to our findings, using Lidocaine 50 mg in combination with Bupivacaine 5 mg, compared with Bupivacaine 10 mg alone for spinal anesthesia in hip fracture fixation surgeries was associated with more hypotension and bradycardia. As a result, combination of Bupivacaine with Lidocaine at this dose is not recommended for induction of anesthesia in these patients.