[Remifentanil versus dexmedetomidine as coadjutants of standardized anesthetic technique in morbidly obese patients]

Abstract

Background and objectives: Two coadjuvant anesthetic drugs - remifentanil and dexmedetomidine - were compared in terms of anesthetic recovery, arterial pH and PaCO2 evolution, in morbidly obese patients submitted to Capella's surgery.

Methods: Participated in this prospective, randomized and double blind study 92 patients divided in two groups and submitted to standardized anesthetic technique (general/epidural). Remifentanil Group (Group R) and Dexmedetomidine Group (Group D) received continuous intravenous infusion of these drugs (0.1 microg.kg-1.min-1 and 0.5 microg.kg-1.h-1, ideal body weight plus 30% for both) immediately after tracheal intubation. Monitoring consisted of invasive mean blood pressure, pulse oximetry, BIS EEG, capnography, peripheral nerve stimulator and EKG. The following parameters were evaluated: 1) different anesthetic recovery times (eye opening, return to spontaneous ventilation, tracheal extubation time, time for post anesthetic recovery unit and hospital discharge); 2) arterial blood gas analysis evolution; and 3) postoperative analgesia.

Results: Evaluation was possible in 88 patients. Patients group R had earlier eye opening (9.49 +/- 5.61 min versus 18.25 +/- 10.24 min, p < 0.0001), faster return to spontaneous ventilation (9.78 +/- 5.80 min versus 16.58 +/- 6.07 min, p < 0.0001), and earlier tracheal extubation (17.93 +/- 10.39 min versus 27.53 +/- 13.39 min, p < 0.0001). There were no differences in times for post-anesthetic recovery unit (105.18 +/- 50.82 min versus 118.69 +/- 56.18 min) and hospital (51.13 +/- 6.37 hours versus 52.50 +/- 7.09 hours) discharge. Both groups showed arterial pH and PaO2 decrease immediately after tracheal extubation as compared to preoperative values, still present at PACU discharge. Group D patients showed higher arterial PaCO2 after tracheal extubation, as compared to preoperative values in the same group (p < 0.05), and opposed to Group R. 41% of Group R and 60% Group D patients (p < 0.02) required rescue analgesia during the first postoperative day.

Conclusions: In the studied population, the association of remifentanil to standardized anesthetic technique has resulted in faster anesthetic recovery, stability of preoperative arterial PaCO2 values during the immediate postoperative period and lower postoperative rescue analgesics consumption, as compared to dexmedetomidine.