Comparison of Intravenous Lignocaine and Esmolol in Attenuating Hemodynamic Response and Cough Reflex during Extubation in Hypertensive Patients under General Anaesthesia

Tracheal extubation carries higher complication rates compared to intubation during general anaesthesia (GA). Thus, various drugs are used to attenuate hemodynamic responses and cough reflex during extubation. We investigated if intravenous (IV) lignocaine and esmolol, given prior extubation, was able to achieve that in hypertensive patients under GA. In this prospective, double-blinded, randomised controlled study, 68 hypertensive patients on treatment undergoing GA were analysed. Group L received IV lignocaine 1 mg/kg while Group E received IV esmolol 1.5 mg/kg, 2 minutes before extubation. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) were recorded at the following interval: before study drug administration (T-0), prior extubation (T-1), 1 minute (T-2), 3 minutes (T-3), 5 minutes (T-4) and 10 minutes (T-5) post-extubation. Group L showed significantly increase in HR at T-2 while SBP and MAP increased significantly from T-1 until T-5. Group E showed a significant reduction in HR at T-1 up to T-5 and significantly lower HR at T-1 and T-2 compared to Group L. Group E showed stable SBP, DBP and MAP at all intervals. In conclusion, IV esmolol at 1.5 mg/kg was able to attenuate the hemodynamic response more pronounced when compared to IV lignocaine at 1 mg/kg from extubation stress in patients with hypertension on treatment. Both lignocaine and esmolol were equally effective in suppressing cough reflex during extubation.

Improved Activation and Hemodynamic Response Function of Olfactory fMRI Using Simultaneous Multislice with Reduced TR Acquisition

Objectives. The respiration could decrease the time synchronization between odor stimulation and data acquisition, consequently deteriorating the functional activation and hemodynamic response function (HRF) in olfactory functional magnetic resonance imaging (fMRI) with a conventional repetition time (TR). In this study, we aimed to investigate whether simultaneous multislice (SMS) technology with reduced TR could improve the blood oxygen level-dependent (BOLD) activation and optimize HRF modeling in olfactory fMRI. Methods. Sixteen young healthy subjects with normal olfaction underwent olfactory fMRI on a 3T MRI scanner using a 64 channel head coil. FMRI data were acquired using SMS acceleration at three different TRs: 3000 ms, 1000 ms, and 500 ms. Both metrics of BOLD activation (activated voxels, mean, and maximum t -scores) and the HRF modeling (response height and time to peak) were calculated in the bilateral amygdalae, hippocampi, and insulae. Results. The 500 ms and 1000 ms TRs both significantly improved the number of activated voxels, mean, and maximum t -score in the amygdalae and insulae, compared with a 3000 ms TR (all P < 0.05 ). But the increase of these metrics in the hippocampi did not reach a statistical significance (all P > 0.05 ). No significant difference in any BOLD activation metrics between TR 500 ms and 1000 ms was observed in all regions of interest (ROIs) (all P > 0.05 ). The HRF curves showed that higher response height and shorter time to peak in all ROIs were obtained at 500 ms and 1000 ms TRs compared to 3000 ms TR. TR 500 ms had a more significant effect on response height than TR 1000 ms in the amygdalae ( P = 0.017 ), and there was no significant difference in time to peak between TR 500 ms and 1000 ms in all ROIs (all P > 0.05 ). Conclusions. The fast image acquisition technique of SMS with reduced TR could significantly improve the functional activation and HRF curve in olfactory fMRI.