Intrathecal morphine is associated with less delirium following hip fracture surgery; a register study
Abstract Purpose Delirium is a common complication after proximal femoral fracture surgery and contributing factors are pain and opioid consumption. The administration of intrathecal morphine may decrease these factors postoperatively and potentially decrease delirium. The aim of this research is to study the association between the use of intrathecal morphine and the occurrence of delirium. Methods A retrospective analysis of a register kept in a non-academic hospital in the Netherlands was performed. The register contained data of all patients with proximal femur fractures that were surgically treated with osteosynthesis or prothesis. Patients receiving spinal anesthesia with local anesthetics (SA-group) were compared with patients receiving spinal anesthesia with the addition of intrathecal morphine (SIM-group). The administration of either SA or SIM was based on the preference of the anesthesiologist. Primary outcome was the incidence of delirium, as defined by the DSM-V classification. Both univariate and multivariate analysis were performed. Results The SA-group consisted of 451 patients and 34 patients were included in the SIM-group. Delirium occurred in 19.7% in the SA-group versus 5.9% in the SIM-group (p=0.046). This association remained significant after correction in multivariate analysis (OR of delirium in the SA group, 95% CI: 1.062 – 21.006, p=0.041). Additionally, multivariate analysis revealed that age, gender, preoperative cognitive impairment and fracture treatment (osteosynthesis or prosthesis) were independently associated with delirium . Conclusion This retrospective study found an independent association between the use of intrathecal morphine and a lower incidence of delirium. This clinically relevant decrease in delirium should be studied in a prospective randomised study.