Analgesia during abdominal aortic aneurysm endovascular repair: remifentanil vs fentanyl-midazolam - a randomized controlled trial

BACKGROUND AND OBJECTIVE: Endovascular repair offers a less surgically invasive procedure for abdominal aortic aneurysms but nevertheless, still requires analgesic sedative cover to ensure an acceptable level of patient comfort and cardiorespiratory stability. The peculiarity of this kind of operation is that painful stimuli are concentrated in specific moments separated by intervals devoid of pain, so the insurgence of pain can be predicted and prevented with a bolus of analgesic, making a continuous infusion not essential, but potentially useful in achieving a better analgesic stability. The primary objective of the study was pain control measured by Visual Analogue Scale; secondary endpoints were cardiorespiratory stability and an acceptable level of sedation. METHODS: The sedative analgesic protocols of two groups of randomly allocated patients, undergoing abdominal aortic aneurysm endovascular repair, were compared. The experimental group received remifentanil infusion (0.03-0.1 microg kg min) and the control group received intravenous doses of fentanyl and midazolam (1-3 microg kg and 0.05-0.1 mg kg, respectively). RESULTS: Fifty patients were investigated out of 60 enrolled. There were no relevant differences concerning cardiorespiratory stability and level of sedation, but pain levels were significantly lower in the experimental group: mean Visual Analogue Scale 0.35+/-0.40 vs. 1.49+/-0.62 (P<0.001) and area under the curve 17.48+/-5.09 vs. 33.05+/-8.19 (P<0.001). CONCLUSION: Both techniques were shown to be safe and most importantly effective in offering cardiovascular stability and analgesia for American Society of Anaesthesiologists III-IV patients undergoing endovascular abdominal aortic aneurysm repair. However, remifentanil continuous infusion proved to offer significantly more stable pain control compared with the currently used combination fentanyl-midazolam.