Background and Goal of Study: Currently, common coinduction agents with propofol to aid LMA insertion include midazolam, fentanyl and alfentanil. In this study, we use small doses of propofol as an auto coinduction agent with propofol during anesthesia induction and LMA placement.
Materials and Methods: 44 ASA 1 & 2 patients scheduled for surgical or orthopaedic procedures under GA were recruited. The study group (PP) received 0.5mg/kg propofol 2 minutes before induction and the control group (SP) received 3 ml saline. Propofol was infused at 50mg/kg/h until loss of eyelash reflex. LMA was inserted when patient was relaxed. We compared the time taken for induction and LMA placement, total dose of propofol consumed, haemodynamics changes during induction and conditions for LMA placement.
Results and Discussions: There is a significant reduction in the dose of propofol required for LMA insertion (100 ± 32.6 mg vs. 166 ± 41.1 mg, p = 0.00) and in the time taken for completion of LMA insertion (98.9 ± 19.3mg vs. 139 ± 42.1 mg, p = 0.00) in the PP group. There was a higher proportion of patients in whom the jaw opening (90.95 vs. 63.6%, p = ) and the ease of LMA insertion (95.5% vs. 59.1%, p = ) were described as good in the PP group. The LMA was inserted within the first attempt in 90% of the patients in the study group. However the incidence of side-effects was similar. There were significant decreases in mean arterial pressure within each group compared to baseline values during induction, but the magnitude of decrease was not different between the 2 groups. Mean heart rate remained stable during the induction process.
Conclusion(s): Small doses of propofol (0.5 mg/kg) given as a pre-dose can be used to augment the induction of anesthesia with propofol and smoothen the process of LMA insertion. Additional drugs need not be used when coinduction is desired, thus reducing the incidence of side effects associated with them. The process of co induction is also simplified by using the same agent.
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