Risk factors for nausea and vomiting after day care general anesthesia in mentally challenged patients undergoing dental treatment.

Clinically, the incidence of postoperative nausea and vomiting (PONV) may be higher in mentally challenged patients than in normal healthy patients. The aim of this study was to investigate the risk factors for PONV after day care general anesthesia in mentally challenged patients undergoing dental treatment. We analyzed data on 231 day care general anesthesia cases involving mentally challenged patients undergoing dental treatment. Anesthetic records for the past 5 years were investigated retrospectively. Ten items (age, body weight, sex, duration of general anesthesia, use of propofol, use of sevoflurane, use of nitrous oxide, use of neostigmine, treatment accompanied with bleeding, and transfusion volume) were selected as risk factors for PONV. Postoperative nausea and vomiting was evaluated using the postoperative check sheet and linear discriminant analysis was performed to distinguish PONV incidence using the 10 items as independent variables. The reliability of the linear discriminant function was evaluated using a misjudgment rate and information criteria (AIC). Postoperative nausea and vomiting was observed in 13 cases out of 231 cases. The discriminant function with the smallest AIC (-25.0718) consisted of two independent variables: y=-0.077x(1)-0.001x(2)+0.0716(x(1)=use of propofol, x(2)=age). The misjudgment rate was 31.6%. This result suggests that PONV decreases when propofol is used and that the incidence of PONV decreases with age. To investigate other risk factors, an additional analysis was performed using 83 out of the 231 cases in which sevoflurane was used as an anesthetic agent. The results of the subgroup analysis suggest that the incidence of PONV decreases in male patients and higher weight patients, although the patient's body weight may be related to age, as the study cohort included many children. It is suggested that the major risks for PONV in mentally challenged patients after day care general anesthesia are no use of propofol, lower age, female sex and lower weight.

[An anesthetic case of a patient with multiple sclerosis and supranuclear palsy].

A 60-year-old female with multiple sclerosis (MS) and supranuclear palsy (PSP) was scheduled for right eye iridotomy, left eye phaco emulcification aspiration and insertion of the intraocular lens. Her medical conditions included prolonged immobility, spastic contracture, and a history of convulsion. She was administered with L-dopa, tizanidine, bacrofen, and dantrorane. Anesthesia was induced with propofol 50 mg and fentanyl 25 microg intravenously, and inhalation of oxygen and 1% sevoflurane. Tracheal intubation was performed without neuromuscular blocking agents. Anesthesia was maintained with inhalation of oxygen-air (Fi(O2) 0.4) and 1-1.5% sevoflurane, combined with regional anesthesia. Supplemental fentanyl was administered as needed. The bispectral index (BIS) was monitored and kept between 40 and 60. The operation proceeded uneventfully. After discontinuation of anesthetic agents, she awoke immediately and the BIS index returned to the pre-induction level. Neither neurological disturbances nor unexpected event were observed postoperatively. In patients with MS, it is important to remember the possibility of drugs moving into the central nervou system easily due to the disturbance of the blood-brai barrier. Patients with PSP are usually medicated wit. various medicines which have possibility of interactin with anesthetics. Therefore, we used least anesthetic as possible. In this case, monitoring of BIS seemed to be useful to maintain the minimum sevoflurane concen trations needed.

Low dose of fentanyl reduces predicted effect-site concentration of propofol for flexible laryngeal mask airway insertion.

PURPOSE: In contrast to reports on the classical laryngeal mask airway (classical LMA; CLMA), no report has calculated the 50% and 95% effect-site concentrations (EC(50) and EC(95), respectively) of propofol required for flexible LMA (FLMA) insertion. This study was designed to determine the EC(50) and EC(95) of propofol for FLMA insertion, using probit analysis, and to investigate whether supplemental 0.25 microg x kg(-1) fentanyl decreased these concentrations. METHODS: Fifty-nine unpremedicated patients who were scheduled for elective minor oral surgery were randomly allocated to a saline-propofol group (S-P group; n = 30) or a fentanyl-propofol group (F-P group; n = 29). Each group was further divided into four subgroups, in which the propofol EC for FLMA insertion was set at 2.5, 3.0, 3.5, and 4.0 microg x ml(-1), respectively, in the S-P group and 1.8, 2.0, 2.5, and 3.0 microg x ml(-1), respectively, in the F-P group. The experiment was assessed as "successful" when FLMA insertion within 1 min was possible. RESULTS: The EC(50) and EC(95) in the S-P group were 3.29 (95% confidence interval [CI], 2.83-3.93) and 4.73 (95% CI, 3.94-12.22) microg x ml(-1), and those in the F-P group were 2.13 (95% CI, 1.42-2.60) and 3.54 95% CI, (2.78-34.78) microg x ml(-1), respectively. The EC(50) in the F-P group was significantly lower than that in the S-P group. There were no significant differences in bispectral index (BIS), hemodynamic variables, respiratory rate, and arterial oxygen saturation (SpO2) between the S-P and F-P groups. CONCLUSION: The propofol EC(50) for FLMA insertion was decreased by supplemental 0.25 microg x kg(-1) fentanyl without BIS, hemodynamic, or respiratory depression.