Epidural pain management after open lateral thoracotomy: Female patients have better pain relief and need smaller amounts of analgesics than males

Abstract

Abstract Background and aims There is an ongoing dispute whether or not there is a gender difference in epidural drug requirements. The objective of this study was to compare the effects of a triple drug epidural mixture used for postoperative pain relief on male and female patients undergoing major surgery. Materials and methods To avoid possible influence of different age and type of surgery only 50–70 year old patients undergoing open lateral thoracotomy were included. 253 patients were enrolled: 116 males and 137 females. All patients received a mixture of bupivacaine 0.1 mg/ml, fentanyl 2 μg/ml, and adrenaline 2 μg/ml (BFA) by continuous infusion into the thoracic epidural space for postoperative pain relief. Infusion rate of the BFA solution was recorded and pain score was evaluated by numeric rating scale (NRS, 1–10) for 48 h post operatively. Results Adequate postoperative pain relief (NRS ≤ 3) at rest was accomplished in 91% of male patients on day one and 92% on day two and by 94% and 100% of female patients, respectively. Females had significantly lower median pain scores than males on day two both at rest (P < 0.011) and by movement (P < 0.012). In addition females required significantly smaller amounts of BFA mixture (P < 0.01) and less frequently rescue opioids (P < 0.025) than males. Conclusion Female patients had significantly better pain relief both at rest and by movement, needed smaller amounts of the epidural bupivacaine, fentanyl, adrenaline mixture for postoperative pain relief and received less frequently rescue opioids than males. Implications The dose of thoracic epidural infusion of low-concentration bupivacaine-, fentanyl-, and adrenaline-solution should routinely be set lower for postmenopausal women than for elderly male patients during and after thoracotomy.