Propofol target-controlled infusions for sedation--a safe technique for the non-anaesthetist?

OBJECTIVE: As an alternative to general anaesthesia for dentistry.attention has been focused on other, apparently safer, methods of pain and anxiety control. We have undertaken a study to evaluate the safety and efficacy of intravenous sedation using propofol target-controlled infusions. DESIGN: We describe a retrospective observational analysis of propofol conscious sedation as an adjunct to local anaesthesia for patients undergoing simple or surgical exodontia. All the patients were assessed,selected and treated according to standardized hospital sedation protocols. Experienced anaesthetists used a standard regimen, with ECG, pulse oximetry and non-invasive blood pressure monitoring. A standard sedation record was completed for each patient. The initial target plasma propofol concentration was set at 1.5 microg ml(-1), adjusted thereafter to achieve the desired level of sedation. Any adverse events were recorded. SETTING: Birmingham Dental Hospital. SUBJECTS: Three hundred consecutive sedation episodes in adult dental phobic patients requiring exodontia under local anaesthesia. RESULTS: Sedation and treatment were satisfactorily completed in 297 patients. The mean target propofol concentration required was 2.1 microg ml(-1), (SD = 0.47 microg ml(-1), range 1 - 4 microg ml(-1)). General anaesthesia occurred in two cases (target concentration (TC) 2 microg ml(-1)), over sedation in 11 cases(TC 1 - 3 microg ml(-1)), and transient hypoxaemia in 7 cases (TC 1.8 - 2.5 microg ml(-1)). CONCLUSION: Intravenous sedation with target-controlled propofol infusions is effective. However, significant adverse effects may occur at target concentrations below 2.1 microg ml(-1). Only anaesthetists working in an appropriate environment should practise this technique.

Cardiac arrhythmias in children during outpatient general anaesthesia for dentistry: a prospective randomised trial.

BACKGROUND: Deaths in children associated with outpatient general dental anaesthesia may be attributable to sudden cardiovascular collapse precipitated by ventricular arrhythmias. A causal link between halothane anaesthesia, ventricular arrhythmias, and deaths has been suggested. We did a prospective, randomised trial to investigate the frequency and character of arrhythmias during anaesthesia with halothane and the alternative anaesthetic agent, sevoflurane. METHODS: 150 children, aged 3-15 years, who needed dental extraction under general anaesthesia were randomly assigned sevoflurane or halothane supplementation of 66% nitrous oxide in oxygen with spontaneous ventilation. The halothane group (n=50) received halothane introduced in 0.75% increments, every two to three breaths, to a maximum of 3.0%, with maintenance at 1.5%. The incremental sevoflurane group (n=50) received sevoflurane introduced in 2% increments increased to a maximum of 8%, with maintenance at 4%. The 8% sevoflurane group (n=50) received sevoflurane introduced at 8%, with maintenance at 4%. FINDINGS: 24 (48%) children receiving halothane had arrhythmias compared with four (8%) receiving incremental sevoflurane (difference 40% [95% Ci for differences 24-56] p<0.0001), and eight (16%) receiving 8% sevoflurane (difference 32% [15-50] p=0.0013). Halothane-associated arrhythmias occurred during dental extraction or emergence and were mainly ventricular. Six (12%) children in the halothane group had ventricular tachycardia. The methods of sevoflurane administration did not differ significantly for the frequency of arrhythmias (p=0.357). Sevoflurane-associated arrhythmias were mainly single supraventricular ectopic beats. INTERPRETATION: There was a strong association between halothane and ventricular arrhythmias, especially ventricular tachycardia. The use of sevoflurane in preference to halothane could contribute to a decline in morbidity and mortality associated with dental anaesthesia.