[Postoperative morphine excess or rational therapy? An exceptional case of applying the morphine equivalent]

We report on a 51-year-old female with a 7 year history of breast cancer. In August 2000 surgical replacement of the 8th thoracic vertebra was performed. From November 2000 the patient developed progressive pain, due to additional spine metastases, leading to pain therapy (according to the patient record) as follows: MST 320 mg oral 4 times daily, Durogesic 100 micrograms/h transdermal, Sevredol 40 mg oral 3 times daily and Ibuprofen 800 mg oral 3 times daily. Due to the risk of spinal instability and persisting pain a thoracic spondylodesis from Th 4-L2 was performed. Parallel to arrival in the PACU the patient developed extremely intensive pain. Pain control was achieved by fractional injection of overall 660 mg morphine in the first 120 min. After interviewing the patient, opioid consumption surprisingly turned out to be 60% higher than presumed. Pain therapy was continued by infusion and PCA with morphine in a daily intravenous dosage of 600-800 mg. Consecutively the pain therapy was switched to oral morphine and co-analgesics and the patient was discharged home 14 days postoperatively.

Some patients with chronic cancer pain are used to increased opioid dosages prior to planned surgery. In the perioperative setting these dosages have to be continued and adapted to current requirements, otherwise analgesic undersupply occurs. In our case report we describe a serious sequence of postoperative analgesic undersupply in an opioid consuming patient. The main principles of post-operative dosing and logistic pitfalls are illustrated.