Remifentanil-based Anesthesia Research Articles

Remifentanil-based anesthesia versus a propofol technique for otologic surgical procedures

Otologic procedures require a still surgical field and are associated with a 50% incidence of emetic symptoms. Propofol reduces nausea and vomiting but not intraoperative movement. This study compares a remifentanil/propofol anesthetic to a propofol/fentanyl combination to determine which provides the best perioperative conditions for otologic microsurgery. Eighty healthy patients were randomly assigned to receive one of the anesthetic combinations. Demographic data, hemodynamic variables, movement, and bispectral index monitoring values in addition to anesthetic emergence, nausea, vomiting, pain, and other recovery variables were compared between groups with appropriate statistical methods. Both groups were similar. Times to eye opening (7.7 ± 0.7 vs 12.4 ± 1.2 minutes) and extubation (9.8 ± 0.9 vs 12.4 ± 1.0 minutes) were shorter with remifentanil. This group also had lower hemodynamic variables and movement (23% vs 65%) under anesthesia. Postoperative pain was mild in both groups, but remifentanil patients had more than the propofol group. All other postoperative parameters were similar. Remifentanil-based anesthesia produces better hemodynamic stability, less movement, and faster emergence after otologic surgery, with propofol’s antiemetic effect, for the same cost. (Otolaryngol Head Neck Surg 2000;122:222-7.)

Inpatient experience with remifentanil.

Inpatient experience with remifentanil.

IS THERE A DIFFERENCE IN ADVERSE EVENTS DURING GENERAL ANESTHESIA BASED ON GENDER, AGE, OR ETHNIC GROUP

S169 Introduction: General anesthesia has been associated with a variety of adverse events (AE). AEs such as hypotension are known to be more common in certain subgroups within the population, for example, in the elderly. However, the incidence of the most common AEs, and their relationship to specific subgroups, has not been well defined. As part of a multicenter study examining remifentanil-based anesthesia (SOURCE), we have defined the incidence of the most common AEs according to age, gender, and ethnic origin. Methods: Following local IRB approval, 250 centers consented and enrolled up to 10 subjects each who received remifentanil in an open-label, observational study. Subjects were males and females 18 years of age and older, ASA status 1-4, and scheduled for elective surgery under general anesthesia expected to last >or=to 30 minutes. Subjects were induced with 0.5-1.0 mcg/kg/min remifentanil concurrently with propofol or thiopental. After intubation, remifentanil was decreased to 0.25 mcg/kg/min and titrated as needed. Subjects received either isoflurane (0.2% end-tidal with N2 O or 0.4% without N2 O) or propofol (50-100 mcg/kg/min with N2 O or 75-150 mcg/kg/min without N2 O) for maintenance hypnosis. Specific AEs examined were intraop hypotension, intra- and postop hypertension and muscle rigidity, and postop respiratory depression and apnea. Statistical analysis was based on logistic regression, which calculated an odds ratio (OR), the odds of a subject experiencing an AE based on demographic factors. Results: A total of 1665 subjects were eligible for the analyses (491 inpatients and 1174 outpatients; 1375 white, 194 black, 72 hispanic, 4 asian, and 20 other). The overall incidence rates were hypotension 16%, hypertension 3%, and respiratory depression, muscle rigidity, and apnea <1. Hypotension was more likely to be experienced by subjects >65 years (OR=3.4; p<0.0001). Hypertension was more likely to be experienced by hispanic and black subjects (OR=3.9; p<.005 and OR=3.2; p<.001, respectively) and by subjects >65 years (OR=3.2; p<.001). Gender was not a risk factor for any adverse event; no subgroup had a statistically significant effect on respiratory depression, muscle rigidity, or apnea. (Table 1 and Table 2)Table 1: Incidence (%) of Hypotension by SubgroupTable 2: Incidence (%) of Hypertension by SubgroupDiscussion: Ethnic origin and age, but not gender, were important factors in the development of hemodynamic adverse events. This would imply that in the future, when evaluating the safety of new anesthetics, ethnic origin, as well as age, must be considered.