Oral clonidine: a simple yet effective and safe premedicant for hemodynamic stability during laparoscopic surgery and a calm post-operative period

Background: Laparoscopy is the essence of modern surgery but the carbon dioxide pneumoperitoneum used therein significantly impairs patient’s cardiopulmonary function. Clonidine, by its central sympatholysis, reduces perioperative hemodynamic instability and also has multiple added advantages in post-operative period.Methods: In this prospective, randomized, double-blind, placebo-controlled study on 60 ASA I/II patients, clonidine 150 µg for weight 55 kg was administered per oral to 30 patients (clonidine group) 90 minutes before induction of general anaesthesia and intra-operative haemodynamics were monitored at specific time periods and compared with the placebo group patients (n=30) who received oral vitamin C. We also noted pre-operative anxiety score, post-operative sedation and pain scores and the presence of nausea-vomiting, shivering and dry mouth at the end of first and sixth postoperative hours.Results: Clonidine group patients remained haemodynamically stable throughout the intra-operative period. In clonidine group, less number of patients required fentanyl for tachycardia (1 vs 11) and NTG for hypertension (none vs 7). Similarly the pain and anxiety scores were significantly less in clonidine group patients. At the end of first postoperative hour incidence of pain, shivering and vomiting in placebo group was 33%, 36% and 20% respectively whereas in clonidine group incidence was 6%, 0 and 0. At the end of 6 post-operative hours, incidence of pain and vomiting was 73% and 36% in placebo group whereas it was 10% and 0 in clonidine group.Conclusions: Oral clonidine in the present dose is able to maintain stable intra-operative haemodynamics and achieve a calm post-operative period during laparoscopic surgeries in ASA I/II patients.

Fundamental studies of supported bimetallic catalysts by NMR spectroscopy

Characterization of a bimetallic catalyst in terms of its surface composition is important in understanding the mechanisms of reactions over such catalysts. Since catalytic surfaces are covered with adsorbates under reaction conditions, the influence of adsorbates on the surface compositions of bimetallic catalysts is also important. Hydrogen was found to influence the surface compositions of silica and alumina supported Pt-Rh catalysts to a certain extent as the surfaces of bimetallic catalysts were enriched in Rh under the influence of hydrogen. Although the extent of Rh enrichment of the surface was not large, the surface compositions in the presence of hydrogen were significantly different from those of an adsorbate-free Pt-Rh surface which is known to be enriched in Pt;Various hydrogenation reactions on transition metals are important commercially whereas certain hydrogenolysis reactions are useful from fundamental point of view. Understanding the hydrogen mobility and kinetics of adsorption-desorption of hydrogen is important in understanding the mechanisms of such reactions involving hydrogen. The kinetics of hydrogen chemisorption was studied by means of selective excitation NMR on silica supported Pt, Rh and Pt-Rh catalysts. The activation energy of hydrogen desorption was found to be lower on silica supported Pt catalysts as compared to Rh and Pt-Rh catalysts. It was found that the rates of hydrogen adsorption and desorption on Pt-Rh catalyst were similar to those on Rh catalyst and much higher as compared to Pt catalyst;The Ru-Ag bimetallic system is much simpler to study than the Pt-Rh system and serves as a model system to characterize more complicated systems such as the K/Ru system. Ag was found to decrease the amounts of adsorbed hydrogen and the hydrogen-to-ruthenium stoichiometry. Ag reduced the populations of states with low and intermediate binding energies of hydrogen on silica supported Ru catalyst. The rates of hydrogen adsorption and desorption were also lower on silica supported Ru-Ag catalyst as compared to Ru catalyst. Thus Ag influenced the kinetics and thermodynamics of hydrogen chemisorption on Ru particles and it was found that electronic and ensemble effects were not responsible for this influence of Ag. Instead, the effect of silver was due to the selective segregation of silver to the edge, corner and other defect-like sites which are proposed to be highly active for dissociative hydrogen adsorption. Hence hydrogen adsorption on Ru particles was found to be structure sensitive

VTrackIt: A Synthetic Self-Driving Dataset with Infrastructure and Pooled Vehicle Information

Artificial intelligence solutions for Autonomous Vehicles (AVs) have been developed using publicly available datasets such as Argoverse, ApolloScape, Level5, and NuScenes. One major limitation of these datasets is the absence of infrastructure and/or pooled vehicle information like lane line type, vehicle speed, traffic signs, and intersections. Such information is necessary and not complementary to eliminating high-risk edge cases. The rapid advancements in Vehicle-to-Infrastructure and Vehicle-to-Vehicle technologies show promise that infrastructure and pooled vehicle information will soon be accessible in near real-time. Taking a leap in the future, we introduce the first comprehensive synthetic dataset with intelligent infrastructure and pooled vehicle information for advancing the next generation of AVs, named VTrackIt. We also introduce the first deep learning model (InfraGAN) for trajectory predictions that considers such information. Our experiments with InfraGAN show that the comprehensive information offered by VTrackIt reduces the number of high-risk edge cases. The VTrackIt dataset is available upon request under the Creative Commons CC BY-NC-SA 4.0 license at http://vtrackit.irda.club

Comparison of effects of rocuronium bromide versus vecuronium bromide on hemodynamic parameters during anaesthesia for elective surgical procedures

Background: Understanding haemodynamic effects of muscle relaxants may help us in selection of most appropriate muscle relaxant in a given case after considering preoperative cardiac status, preoperative medications, anaesthetic drugs to be used, nature of surgery and desirable intraoperative hemodynamics. Hemodynamic effects of rocuronium are not as clear as vecuronium. Present study was conducted to compare haemodynamic parameters during general anaesthesia for elective surgical procedures with vecuronium vs. rocuronium as muscle relaxant.Methods: Haemodynamic effects of vecuronium 0.15 mg/kg and 0.9 mg/kg of rocuronium was evaluated in patients (25 patients in each group) undergoing elective surgical procedures not lasting more than two hours. During this study period patients were evaluated for heart rate (HR), systolic BP (SBP), diastolic BP (DBP) and mean arterial pressure (MAP).Results: When both groups were compared, degree of fall in heart rate was more in vecuronium group (V group) compared to rocuronium group at all-time intervals after administration of drug. The fall in mean heart rate in V group was significant at two minutes after administration of muscle relaxant when compared to R group i.e.77.12±9.96 vs. 85.04±12.82 (p<0.05) and was highly significant at 3 minutes after administration of drug i.e. 76.12±9.67 vs. 85.44±12.47 (p<0.001). After induction and administration of vecuronium or rocuronium there was fall in systolic blood pressure, diastolic blood pressure and mean arterial pressure in both the groups when these parameters were recorded before laryngoscopy with slightly more but comparatively non-significant fall in these parameters in vecuronium group. Intraoperatively these parameters were comparable in both groups and no significant difference from baseline was observed in these parameters in both groups thereby showing good haemodynamic stability.Conclusions: Vecuronium is associated with greater decrease in heart rate than rocuronium in clinical doses. No increase in heart rate was observed with rocuronium in doses used. In all other aspects (SBP, DBP, MAP) haemodynamic effects were similar in both groups with slightly greater but non-significant fall observed after administration of vecuronium group

Patterns of Post-thyroidectomy Hemorrhage

ObjectivesPostoperative hemorrhage is a potentially life-threatening complication in thyroid surgery. This study was performed to review the clinical patterns of post-thyroidectomy hemorrhage, and especially as they are related to the source of bleeding.MethodsWe performed a retrospective review of 10 patients (0.96%) with post-thyroidectomy hemorrhage that required surgical evacuation. The clinical patterns such as the time interval from surgery to hemorrhage and the signs and symptoms according to the bleeding focus were evaluated.ResultsThe mean time interval from surgery to symptom onset was 7 hr 52 min. Six cases showed bleeding deep to the strap muscles, while the other 4 cases showed bleeding superficial to the muscles. Ecchymosis was prominent and dark in color in 3 of the 4 cases (75%) of superficial bleeding, however it was identified in only 2 of the 6 cases (33%) of deep bleeding. Respiratory distress occurred in two cases of hematoma deep to the strap muscles, but in none of the cases with superficial bleeding.ConclusionThe post-thyroidectomy hemorrhage had some different clinical patterns between the superficial cases and the deep cases, showing that life-threatening airway obstruction occurred from the deep hematoma. A thorough understanding of the clinical patterns of post-thyroidectomy hemorrhage between the cases of superficial and those cases of deep hematoma may provide valuable surgical tips to manage this potentially lethal complication

Fundamental studies of supported bimetallic catalysts by NMR spectroscopy

Various hydrogenation reactions on transition metals are important commercially whereas certain hydrogenolysis reactions are useful from fundamental point of view. Understanding the hydrogen mobility and kinetics of adsorption-desorption of hydrogen is important in understanding the mechanisms of such reactions involving hydrogen. The kinetics of hydrogen chemisorption was studied by means of selective excitation NMR on silica supported Pt, Rh and Pt-Rh catalysts. The activation energy of hydrogen desorption was found to be lower on silica supported Pt catalysts as compared to Rh and Pt-Rh catalysts. It was found that the rates of hydrogen adsorption and desorption on Pt-Rh catalyst were similar to those on Rh catalyst and much higher as compared to Pt catalyst. The Ru-Ag bimetallic system is much simpler to study than the Pt-Rh system and serves as a model system to characterize more complicated systems such as the K/Ru system. Ag was found to decrease the amounts of adsorbed hydrogen and the hydrogen-to-ruthenium stoichiometry. Ag reduced the populations of states with low and intermediate binding energies of hydrogen on silica supported Ru catalyst. The rates of hydrogen adsorption and desorption were also lower on silica supported Ru-Ag catalyst as compared to Ru catalyst. This report contains introductory information, the literature review, general conclusions, and four appendices. An additional four chapters and one appendix have been processed separately for inclusion on the data base