Does femoral nerve analgesia impact the development of postoperative delirium in the elderly? A retrospective investigation

Summary 

Background

The potential effects of femoral nerve analgesia on postoperative delirium and length of stay remains poorly investigated. After detecting several cases of delirium in postoperative patients, we sought to find out if femoral nerve analgesia would prove superior in the prevention of postoperative delirium when compared to a conventional analgesia regimen.

Methods

Ninety-nine (99) patients were retrospectively investigated for delirium following hip fracture repair in 1 year (October 2004–October 2005). Patients were divided in two groups: Group 1 (n=49) received patient-controlled femoral nerve analgesia (PCAF), Group 2 (n=50) were treated with intravenous analgesia. All patients were studied for the following variables: age, gender, previous dementia, length of hospitalisation, blood transfusion, haemoglobin level at discharge, delirium, respiratory failure or oxygen therapy, heart failure or acute coronary disease, renal failure, stroke, rescue opioid analgesia, sitting and walking times, patients discharge to rehabilitation centre and patients discharge without walking recovery.

Results

Patients in Group 1 showed significantly less occurrence of postoperative delirium than those treated with conventional analgesia (8.2% and 42%, respectively). Patients in PCAF group did not receive any morphine rescue medication in contrast to 28% of those of Group 2 (p<0.001). Peripheral nerve analgesia substantially reduced the time when patients could first sit at their bedside (1.6±0.6 and 2.0±0.8, respectively).

Conclusions

The incidence of postoperative delirium was lower in the PCAF group. The PCAF technique in hip fracture repair improves the quality of postoperative analgesia, without needing rescue opioid analgesia.

Keywords: Hip fracture, Femoral analgesia, Postoperative delirium