Postoperative analgesia with minidose intrathecal morphine for bipolar hip prosthesis in extremely elderly patients

It is known that an optimal dose of intrathecal morphine for analgesia after total hip arthroplasty in older patients is 0.1 mg. On the other hand, minidose intrathecal morphine (0.05 mg) is useful for analgesia after the transurethral resection of the prostate in elderly patients. We evaluated the postoperative analgesic effect of minidose intrathecal morphine after bipolar hip prosthesis in seniors (age 85 years or more) undergoing spinal anesthesia.

Twenty seniors undergoing bipolar hip prosthesis under spinal anesthesia were randomly allocated to one of two groups. Group A (n = 10) received intrathecal injection of 0.5% isobaric bupivacaine, 2.8 ml, and group B (n = 10) received intrathecal injection of 0.5% isobaric bupivacaine, 2.8 ml, plus morphine, 0.05 mg. Pain, nausea, and itching were evaluated using a numerical rating scale, ranging from 0 to 10, at 0, 4, 8, 12, and 24 h after the operation.

The values on the numerical rating scale for pain in group B were significantly lower than those in group A at 4, 8, and 12 h after the operation. There were no significant differences between the groups in the values on the numerical rating scale for nausea or itching throughout the time course of the study. No patient in either group showed hypoxemia or respiratory depression throughout the time course.

The results show that minidose intrathecal morphine provides a good analgesic effect without side effects, and it would be an effective and safe procedure for bipolar hip prosthesis in seniors.