RESUMO
BACKGROUND: Low flow anesthesia can lead to reduction of anesthetic gas and vapor consumption. Laryngeal mask airway (LMA) has proved to be an effective and safe airway device. The aim of this study is to assess the feasibility of laryngeal mask airway during controlled ventilation using low fresh gas flow (1.0 L/min) as compared to endotracheal tube (ETT). PATIENTS AND METHODS: Fifty nine non-smoking adult patients; ASA I or II, being scheduled for elective surgical procedures, with an expected duration of anesthesia 60 minutes or more, were randomly allocated into two groups - Group I (29 patients) had been ventilated using LMA size 4 for females and 5 for males respectively; and Group II (30 patients) were intubated using ETT. After 10 minutes of high fresh gas flow, the flow was reduced to 1 L/min. Patients were monitored for airway leakage, end-tidal CO(2)(ETCO(2)), inspiratory and expiratory isoflurane and nitrous oxide fraction concentrations, and postoperative airway-related complications. RESULTS: Two patients in the LMA-group developed initial airway leakage (6.9%) versus no patient in ETT-group. Cough and sore throat were significantly higher in ETT patients. There were no evidences of differences between both groups regarding ETCO(2), uptake of gases, nor difficulty in swallowing. CONCLUSION: The laryngeal mask airway proved to be effective and safe in establishing an airtight seal during controlled ventilation under low fresh gas flow of 1 L/min, inducing less coughing and sore throat during the immediate postoperative period than did the ETT, with continuous measurement and readjustment of the tube cuff pressure.
RESUMO
BACKGROUND AND OBJECTIVE: The use of sevoflurane in paediatric anaesthesia which could enable rapid recovery is complicated by the frequent occurrence of emergence agitation. The aim of this study was to test the efficacy of supplementing midazolam-based oral premedication with low-dose oral ketamine in reducing sevoflurane-related emergence agitation. METHODS: Ninety-two healthy preschool children who have been scheduled for elective dental procedures under general anaesthesia were allocated into two groups (46 patients for each): group M received oral midazolam 0.5 mg kg(-1), whereas group KM received similar premedication in addition to ketamine 2 mg kg(-1). Acceptance of drug mixture and onset of action were monitored over the next 30 min. Induction of anaesthesia was carried out using sevoflurane 8 vol% in 100% oxygen via face mask. Anaesthesia was maintained with sevoflurane 1.5-2 vol% in oxygen-nitrous oxide mixture. Following extubation, standard scoring scale was used for assessing quality of emergence. Agitation parameters were measured using a five-point scale. Agitated children were managed by giving intravenous increments of fentanyl 1 microg kg(-1). The time of hospital discharge allowance was recorded. RESULTS: Vast majority of children accepted the premedication. There were no significant differences between both groups regarding recovery from sevoflurane and allowance of hospital discharge. Onset of action of premedication was shorter in group KM. Similarly, postoperative agitation score and rescue fentanyl consumption were markedly lower in group KM upon admission to the postanaesthesia care unit (P<0.01). CONCLUSION: Adding a low dose of oral ketamine to midazolam-based oral premedication in preschool children undergoing dental surgery reduced emergence agitation without delaying hospital discharge.
