RESUMO
BACKGROUND AND AIMS: Insertion of laryngeal mask airway (LMA) requires adequate depth of anaesthesia, which provides jaw relaxation and suppression of upper airway reflexes. Propofol can provide these conditions especially when combined with narcotics. This study had been designed to find out the effect-site concentration (EC50) of propofol using target controlled infusion (TCI) when fentanyl or morphine is added as an adjuvant. METHODS: Patients satisfying inclusion criteria were divided into fentanyl and morphine groups. Intravenous glycopyrrolate 0.2 mg was given 15 min before induction. Patients were given either intravenous fentanyl (1 µg/kg) or morphine (0.1 mg/kg) before propofol infusion depending on the group. Patients in either groups were induced by continuous infusion of propofol at an EC of 6 µg/mL by TCI with Schneider pharmacokinetic model. The LMA supreme of appropriate size was inserted 1 min after achieving target concentration. Patient movement at LMA insertion or within 1 min of insertion was classified as failure. For subsequent patients, the target EC was increased/decreased depending on previous patients' response. Dixons up and down method was used to determine the EC50. The EC50 is defined as the mean of crossover midpoints in each pair of failure to success. RESULTS: The EC50 of propofol in the fentanyl group for LMA insertion was 5.95 ± 0.6 µg/ml and morphine group was 5.75 ± 0.8 µg/ml. No significant difference in insertion conditions was noticed between the two groups (P = 0.3). CONCLUSION: We conclude that there was no significant difference in propofol EC50 for insertion of LMA and insertion conditions were similar when fentanyl or morphine was used as an adjuvant drug.
RESUMO
BACKGROUND: Truview(PCD) laryngoscope is specially designed to aid positioning of the endotracheal tube as well as to record entry of the tube into glottis. Aim of the study is to compare the view of glottic opening and ease of intubation between Truview(PCD) laryngoscope and Macintosh laryngoscope in patients undergoing general anesthesia (GA). METHODOLOGY: Two hundred patients undergoing elective surgery, under GA were randomized into two groups, Group TV and Group ML. In Group TV, Trueview(PCD) laryngoscope was used initially to visualize the vocal cords for Cormack and Lehane grading (CLG) and to spray the vocal cords with 10% lignocaine. Then the patient was ventilated for 1 min and Macintosh laryngoscope was used to visualize the vocal cords for CLG and proceed with intubation. In Group ML, Macintosh laryngoscope was used initially and later Truview(PCD) laryngoscope. Time to intubation, CLG, number of attempts and hemodynamic parameters were recorded. RESULTS: Ninety-six and 89 patients had CLG1 visualization when Truview(PCD) laryngoscope was used as 1(st) and 2(nd) device respectively compared to 41 and 68 with Macintosh laryngoscope (P = 0.00). Four patients had CLG 4 visualization with Macintosh laryngoscope that turned out to be grade II visualization with Truview(PCD) laryngoscope (P = 0.00). Mean time taken for intubation with Truview(PCD) and Macintosh laryngoscope was 21.10 ± 5.64 s and 15.79 ± 2.76 s respectively (P = 0.00). CONCLUSION: Better visualization with lesser CLG was found with Truview(PCD) laryngoscope but it took longer time for intubation than Macintosh laryngoscope. The hemodynamic response to intubation was significantly less with the use of Truview(PCD) laryngoscope when compared to that of Macintosh laryngoscope.
RESUMO
Positioning the parturient from supine to the left lateral tilt position (supine-to-tilt) may not effectively displace the gravid uterus, but turning from the left lateral position to the left lateral tilt position (left lateral-to-tilt) may keep the gravid uterus displaced and prevent aortocaval compression. Fifty-one full-term parturients were randomly placed in the left lateral position, supine-to-tilt and left lateral-to-tilt positions using a Crawford wedge. Femoral vein area, femoral vein velocity, femoral artery area, pulsatility index, resistance index and right arm mean arterial blood pressure and heart rate were recorded. Our results showed a lower mean (SD) femoral vein area (82.2 (14.9) vs 96.2 (16.4) mm(2)), a lower pulsatility index (3.83 (1.3) vs 5.8 (2.2)), a lower resistance index (0.93 (0.06) vs 0.98 (0.57)), a higher femoral artery area (33.3 (3.8) vs 30.9 (4.4) mm(2)) and a higher femoral vein velocity (7.9 (1.2) vs 6.1 (1.6) cm.s(-1)) with left lateral-to-tilt when compared with supine-to-tilt (all p < 0.001). Our results suggest that moving a full-term parturient from the full left lateral to the lateral tilt position may prevent aortocaval compression in full-term parturients more efficiently than when positioning the parturient from a supine to left lateral tilt position.
