Anesthesia and analgesia
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Anesthesia and analgesia · Apr 1999
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of epidural ropivacaine infusion alone and in combination with 1, 2, and 4 microg/mL fentanyl for seventy-two hours of postoperative analgesia after major abdominal surgery.
Our aim in this prospective, randomized, double-blinded study was to compare the analgesic effectiveness and side effects of epidural infusions with ropivacaine 2 mg/mL alone (Group R; n = 60) and in combination with fentanyl 1 microg/mL (R1F; n = 59), 2 microg/mL (R2F; n = 62), and 4 microg/mL (R4F; n = 63) for up to 72 h after major abdominal surgery. Effective epidural neural blockade was established before surgery; postoperatively, the infusion rate was titrated to a maximum of 14 mL/h for analgesia. No additional analgesics other than acetaminophen were permitted during the infusion. The median of individual visual analog scale score with coughing were <20 mm for all groups (0 = no pain, 100 = worst pain) and was significantly lower (P < 0.01) for Group R4F at rest and with coughing (compared with Group R). Infusions were discontinued due to inability to control pain in significantly fewer patients in Group R4F (16%) than the other groups (34% to 39%; P < 0.01). For all groups, >90% of patients had no detectable motor block after 24 h. Hypotension, nausea, and pruritus were more common with the larger dose of fentanyl. We conclude that, after major abdominal surgery, an epidural infusion of ropivacaine 2 mg/mL with fentanyl 4 microg/mL provided significantly more effective pain relief over a 3-day period than ropivacaine alone or ropivacaine with lower concentrations of fentanyl. ⋯ Postoperative epidural analgesic infusions are widely used, but there is little information regarding optimal strengths of opioid with local anesthetic. In this blinded, prospective study, we compared four different epidural infusion solutions for efficacy and side effects over a clinically useful postoperative period and conclude that an epidural infusion of ropivacaine 2 mg/mL with fentanyl 4 microg/mL was most effective.
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Anesthesia and analgesia · Apr 1999
Randomized Controlled Trial Comparative Study Clinical TrialThe target plasma concentration of propofol required to place laryngeal mask versus cuffed oropharyngeal airway.
To determine the target plasma concentration of propofol required to place either a laryngeal mask airway (LMA) or a cuffed oropharyngeal airway (COPA), we started a continuous target-controlled infusion of propofol in 60 ASA physical status I or II unpremedicated patients scheduled for minor orthopedic surgery with peripheral nerve block. The target plasma concentration of propofol was initially set at 2 microg/mL. When the effect-site calculated concentration of propofol was equal to the plasma concentration according to the computer simulation, the target plasma concentration was increased by 0.5-microg/mL steps until successful placement of either the LMA (n = 30) or the COPA (n = 30). The mean target plasma concentration of propofol required to place a LMA was 4.3 +/- 0.8 microg/mL compared with 3.2 +/- 0.6 microg/mL to place a COPA (P < 0.001). To successfully place the airways in 95% of patients, the target plasma concentration of propofol had to be increased up to 4 microg/mL for the COPA and 6 microg/mL for the LMA. We conclude that placing a LMA in healthy, unpremedicated patients requires target plasma concentrations of propofol higher than those required for placing a COPA. ⋯ We evaluated the use of target-controlled infusion of propofol to place extratracheal airways in this prospective, randomized study and demonstrated that the target plasma concentration of propofol required to successfully place a laryngeal mask in >95% of healthy, unpremedicated patients is 6 microg/mL, compared with 4 microg/mL to place a cuffed oropharyngeal airway.