Background: Surgical repair of fractured neck of femur in the elderly is frequently performed under spinal anaesthesia. Elderly patients are particularly susceptible to developing hypotension with this technique. The use of single shot, low-dose bupivacaine/fentanyl spinal anaesthesia has been shown to significantly reduce the incidence of hypotension. This clinical audit compares the haemodynamic stability and the adequacy of the sensory block duration in elderly patients receiving low-dose bupivacaine spinal anaesthesia with patients receiving standard dose spinal anaesthesia.
Method: Data from 60 elderly patients who had undergone surgical repair of fractured neck of femur within the same time period was collected using theatre coding records and systematic review of clinical notes. Thirty patients received a low-dose (4mg) bupivacaine plus 20 μg fentanyl spinal anaesthetic (LDSA), 30 received a standard dose (10-14 mg) bupivacaine plus fentanyl (10-20 μg) spinal anaesthetic (SDSA). Significant hypotension was defined as a systolic pressure decrease equal to or more than 25% of base line value or absolute value ≤90 mmHg.
Results: 76% of the SDSA group compared to 10% of the LDSA group experienced significant hypotension. Decreases in mean systolic pressures from baseline over time were significantly greater in the SDSA group (p<0.001). The incidence of inadequate surgical blocks was higher in the LDSA group at 26% (n=8) compared to 3% (n=1) in the SDSA group. Six of the 8 LDSA patients with inadequate blocks reported pain/discomfort around wound closure.
Conclusion: In our elderly patients low-dose bupivacaine/fentanyl spinal anaesthesia provides greater haemodynamic stability compared to standard dose spinal anaesthesia during surgical repair of hip fractures. In a small percentage of patients in the LDSA group the surgical time outlasted the sensory block duration however, local anaesthetic applied to the operation site allowed uneventful completion of surgery.