Opioid reducing strategies in post-operative pain management

Detta är en avhandling från Stockholm : Karolinska Institutet, Department of Physiology and Pharmacology

Sammanfattning: Adequate pain treatment is motivated by humanitarian grounds. It also seeks to reduce morbidity, improve recovery and diminish risks of persistent postoperative pain. The present Study I evaluates patient-controlled analgesia (PCA) against conventional nurse-administered opioid therapy. Studies II to IV are randomised, placebo-controlled investigations by RCTs of pain severity and opioid consumption following breast-cancer surgery and caesarean section in women treated with a combination analgesic approach. The general aim was to investigate strategies for reduced pain and opioid consumption in patients suffering moderate-to-severe postoperative pain. PCA evaluation and early versus long term pain: Self-administration of opioids after breast cancer surgery was compared to conventional nurse-administered opioid treatment in 144 women. Effect variables were visual analogue pain (VAS) scores and opioid requirements. Four years after surgery, patients completed a questionnaire regarding persistent pain. Pati ent- controlled analgesia provided better pain relief with higher opioid consumption postoperatively. The prevalence of pain persisting after 3-4 years was 25%. In conclusion: PCA technique was superior to conventional nursecontrolled intravenous treatment in relieving pain after breast cancer surgery at higher opioid consumption. Immediate breast reconstruction (IBR) generates intense post-operative pain that responds poorly to opioids. Axillary dissection however is more predictive of persistent pain. Diclofenac after caesarean delivery: Pain after caesarean section is related to uterine contractions poorly responsive to systemically administered opioids. As non-steroidal anti-inflammatory drugs (NSAIDs) have good effect on menstrual pain thought to affect uterine pain mechanisms, we studied how far the required dose of opioids could be decreased by adding diclofenac - an NSAID - to opioid PCA, in 50 women delivered by caesarean section. Ketobemidone demand was 39% less in the diclofenac group. No patient had bleeding complications after surgery. In conclusion: 150 mg diclofenac as an adjunct reduced the need for opioids significantly during the first 24 h after caesarean delivery, with maintained or improved analgesic effect. Diclofenac after mastectomy and 1BR: Aiming at satisfactory rest and functional pain relief for 64 hours after IBR we studied diclofenac as an adjunct to paracetamol and opioid PCA in 48 women. Primary outcome measures were pain intensity at rest and on movement and opioid consumption. Secondary outcome measures were per- and postoperative bleeding, nausea and tiredness. Pain relief at rest was significantly less for 20 h with diclofenac. During movement there was a non-significant difference. Opioid consumption the first 6 h postoperatively was significantly - 34% - less in the diclofenac group. Postoperative bleeding was greater with diclofenac than with placebo. In conclusion: diclofenac 150 mg/24 h added to paracetamol and opioids, reduced opioid consumption for 6 hours and improved pain relief during the first 20 h at rest but was not convincingly effective during mobilisation. Postoperative blood loss was higher with diclofenac. Local anaesthesia after delayed breast reconstruction (DBR): Forty-three women earlier undergoing surgery for breast cancer and scheduled for unilateral DBR with subpectoral tissue expander implant were investigated. The purpose was to evaluate the analgesic efficacy of local anaesthesia (levobupivacaine) via an indwelling catheter in the operation area every 3 h for 45 h in combination with paracetamol and opioid PCA. Effect variables were pain intensity at rest and on mobilisation, and opioid consumption. The levobupivacaine group reported significantly lower pain intensity at rest during the first 15 hours after surgery. During mobilisation there were significant positive differences in pain in this group for the first 6 hours and for the time interval 18-24 hours post-surgery. Total opioid consumption was not significantly lower. In conclusion: Local anaesthesia in addition to opioids and paracetamol improved pain relief at rest and on movement after DBR, with a non-significant reduction in need for opioids. The general conclusion is that the drug combinations investigated resulted in reduced opioid consumption and improved pain relief, but that unacceptable pain is still experienced during the postoperative period.

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