Anesthetic Sparing Research Articles

Is the use of a local anaesthetic during canine castrations inhalational anaesthetic sparing?

Is the use of a local anaesthetic during canine castrations inhalational anaesthetic sparing?

Erector spinae plane versus paravertebral versus multiple intercostal nerve blocks in patients undergoing vats; A randomized controlled trial

BackgroundVideo-assisted thoracoscopic surgery (VATS) is a minimally invasive technique with shorter recovery times and lesser postoperative pain than open thoracotomies. Regional blocks decrease the anesthetic and postoperative analgesic requirements. Methods105 patients scheduled for VATS under general anesthesia were included. Patients were randomly allocated to receive 20 ml of bupivacaine 0.5 % mixed with adrenaline 2 mcg/ml by ultrasound-guided erector spinae plane block (ESPB) at T5 level (Group ESPB, n = 35), 20 ml of bupivacaine 0.5 % mixed with adrenaline 2 mcg/ml by paravertebral block (PVB) at T5 level (Group PVB, n = 35), or multiple intercostal nerve blocks (Group MICNB, n = 35) where 2–3 ml of bupivacaine 0.5 % mixed with adrenaline 2 mcg/ml for each intercostal space from the third to the eighth intercostal nerve were injected by the surgeon through the thoracoscope. The objectives of this study were primarily to assess the effectiveness of the erector spinae plane versus paravertebral versus multiple intercostal nerve blocks on the intraoperative patient anesthetic requirements and secondarily to assess the postoperative analgesic requirements. ResultsNo significant differences were observed regarding End tidal Sevoflurane (Et Sevo) all over the operative time between the ESPB and the PVB group; however there were highly significant differences between either group and the MICNB group immediately after induction of anesthesia till 60 min later, No significant difference between ESPB and the PVB groups as regards to the total amount of intraoperative fentanyl consumption, on the other hand there were highly significant difference between the ESPB or the PVB group and the MICNB group; while all the three groups provide comparable postoperative analgesia with non-significant difference regarding the postoperative VAS either during rest or cough. ConclusionESPB and PVB provided better intraoperative anesthetic sparing effect than MICNB; however all the three blocks provide comparable postoperative analgesia either during rest or during cough in patients undergoing VATS.

Anaesthetic-sparing effect of the anxiolytic drug tasipimidine in Beagle dogs

ObjectiveTo evaluate the effect of oral tasipimidine on dog handling, ease of catheter placement and propofol and isoflurane requirements for anaesthesia. Study designPlacebo-controlled, randomized, blinded, experimental trial. AnimalsA group of seven adult Beagle dogs weighing (mean ± standard deviation) 13.1 ± 2.7 kg with a mean age of 18.6 ± 1 months. MethodsThe dogs underwent four treatments before induction of anaesthesia with propofol. PP: placebo orally (PO) 60 minutes before induction of anaesthesia followed by placebo (NaCl 0.9%) intravenously (IV). TP: tasipimidine 30 μg kg–1 (PO) 60 minutes before induction of anaesthesia followed by placebo (NaCl 0.9%) IV. TMP: tasipimidine 30 μg kg–1 PO 60 minutes before induction of anaesthesia followed by methadone 0.2 mg kg–1 IV. TMPD: tasipimidine 30 μg kg–1 PO 60 minutes before induction of anaesthesia followed by methadone 0.2 mg kg–1 and dexmedetomidine 1 μg kg–1 IV followed by a dexmedetomidine constant rate infusion of 1 μg kg–1 hour–1.Sedation, response to catheter placement, intubation quality, time to loss of consciousness, time to intubation, required dose of propofol and minimum alveolar isoflurane concentration preventing motor movement (MACNM) were determined.A mixed-model analysis or the Friedman and Mann–Whitney test were used; p-value < 0.05. ResultsResponse to catheter placement did not differ between treatments. Tasipimidine alone reduced the propofol dose by 30%. Addition of methadone or methadone and dexmedetomidine reduced the propofol dose by 48% and 50%, respectively. Isoflurane MACNM was reduced by 19% in tasipimidine-medicated dogs, whereas in combination with methadone or methadone and dexmedetomidine, isoflurane MACNM was reduced by 35%. Conclusions and clinical relevanceAn anxiolytic dose of tasipimidine induced mild signs of sedation in dogs and reduced propofol and isoflurane requirements to induce and maintain anaesthesia, which needs to be considered in an anaesthetic plan.

EFFECTS OF INTRAVENOUS INFUSION OF DEXMEDETOMIDINE ON PERIOPERATIVE HEMODYNAMIC &amp; POST OPERATIVE RECOVERY IN LAPAROSCOPIC SURGERIES

Dexmedetomidine is a highly selective and specic α2-adrenoceptor agonist. By its central sympatholytic action, it promotes haemodynamic stability when used as adjuvant during general anaesthesia. It has analgesic and anaesthetic sparing property. It has potent sedative properties. The aim of the study is to assess the effect of intravenous dexmedetomidine on perioperative hemodynamic and also postoperative recovery in laparoscopic surgeries.

Study of the effects of dexmedetomidine on hemodynamic parameters and extubation quality in patients undergoing ENT surgery under general anaesthesia

In ENT surgeries most of the cases are done under general anaesthesia and should be extubated smoothly. If a patient is lightly anesthetised, tracheal and laryngeal irritation can stimulate reflex responses during extubation like bucking, gagging, breath holding, laryngospasm, pulmonary oedema. Alpha 2-Adrenergic agonists are used for their sympatholytic, sedative, anaesthetic sparing and haemodynamic stabilizing properties. We aimed to study the extubation quality and hemodynamic parameters of dexmedetomidine undergoing ENT surgeries under general anaesthesia.This observational study included 100 patients undergoing ENT surgery under general anaesthesia, between 18 to 60yrs. Patients were divided into group P (n=50) and group PD (n=50). A standard general anaesthesia technique according to the Ent operation theatre protocol were followed for all patients. For maintenance group P received inj.Propofol 4mg/kg/hr and group PD received inj. Propofol 4mg/kg/hr and inj. Dexmedetomidine infusion 0.5ug/kg/hr as a standard protocol. Respective infusions were stopped at the start of skin closure. Heart rate, systolic blood pressure and diastolic blood pressure were recorded at the time of extubation and at 1,3,5. minutes till 30 minutes after extubation. Quality of extubation was evaluated using 5-point rating scale (extubation quality score) at extubation.The mean heart rate in the group P was 92/min while in the group PD was 75/min. The mean systolic blood pressure in the group P was 116mmhg while in the group PD was 108mmhg. The mean diastolic blood pressure in the group P was 85mmhg and 67mmhg in group PD (P&amp;#60;0.001). 11 patients of group p got extubation quality score of 2 while 41 cases of group PD got a score of 2(P&amp;#60;0.001).InjDexmedetomidine provides stable hemodynamic parameters during extubation and provides better extubation quality score.

Clinical Applications of Substance P (Neurokinin-1 Receptor) Antagonist in Canine Medicine.

Substance P binds to the Neurokinin-1 (NK-1) receptors found in the emetic center of the central nervous system (CNS) to induce emesis. Maropitant is a selective NK-1 receptor antagonist that inhibits the binding of substance P to NK-1 receptors and is commonly used to prevent and treat vomiting in dogs. This review study aimed to discuss and analyze the therapeutic potential of substance P (Neurokinin-1 receptor) antagonist with a particular focus on the drug maropitant in canine medicine. A systematic literature review was performed to identify the existing literature on the subject during the past 20 years (2001-2021) using such databases as ScienceDirect, PubMed, Scopus, and Google Scholar. The initial search identified 173 articles; however, 41 articles were selected for further analysis, based on the specific inclusion and exclusion criteria. Studies have already confirmed the role of substance P and NK-1 receptors in central pain processing, intestinal smooth muscle contraction, vasodilation, and neurogenic inflammation. Maropitant is one of the most effective veterinary antiemetic drugs that work well against peripheral and central stimuli that trigger the vomiting center. It has been already demonstrated that the therapeutic efficacy of maropitant for managing acute vomiting in dogs is associated with pancreatitis, gastritis, and parvoviral enteritis. It can also prevent and treat chemotherapy-induced emesis and delay the signs of nausea and adverse gastrointestinal effects. Regarding the broad-spectrum antiemetic activity of maropitant, it can be recommended for managing uremic vomiting in dogs. In addition, it has also exhibited an anesthetic sparing effect since the dogs treated with maropitant require a slightly lower percentage of isoflurane as an inhalational anesthetic. The NK-1 receptors are also identified in different areas of the pain pathways. Therefore, NK-1 receptor antagonists might be effective for managing visceral pain. However, further studies are required to establish the broad therapeutic potential of NK-1 receptor antagonist drugs, such as maropitant in canine medicine. It has been shown that the pain associated with the subcutaneous administration of maropitant is due to metacresol, a preservative used in some formulations. Therefore, the side effects can be eliminated by developing novel maropitant formulations specifically for dogs.

Supraclavicular Brachial Plexus Block: Comparison of Varying Doses of Dexmedetomidine with Ropivacaine

Background Alpha-2 adrenergic receptor agonists have been the focus of interest nowadays as an adjuvant to local anesthesia due to its excellent sedative, analgesic, antihypertensive, anesthetic sparing and hemodynamic stabilizing properties. The ideal dose of dexmedetomidine for brachial plexus block is matter of debate.&#x0D; Objective To find the appropriate minimal dose of dexmedetomidine with desired clinical effects and minimal side-effects, we compared different doses (25 mcg, 50 mcg, 75 mcg and 100 mcg) of dexmedetomidine as an adjuvant to ropivacaine.&#x0D; Method One hundred fifty patients of ASA I and II, aged (18-60) years, weighing (50-60) kilograms undergoing upper limb surgeries under brachial plexus block were enrolled in this prospective, double blind, randomized control study. Patients in all group received 19 ml of 0.5% ropivacaine in common. In addition; group RD25, RD50, RD75 and RD100 received 25 mcg, 50 mcg, 75 mcg and 100 mcg of dexmedetomidine diluted in 1 ml of normal saline (NS) respectively whereas group RD00 received only 1 ml of NS. The duration of analgesia was the primary outcome whereas block characteristics, hemodynamic parameters, oxygen saturation, sedation score and adverse effects were taken as secondary outcome. Statistical analysis was done using ANOVA test, Chi-square test and Scheffe’s multiple comparison tests.&#x0D; Result The demographic profile and baseline hemodynamic variables were comparable in all five groups. Increasing dose of dexmedetomidine showed significant improvement in block characteristics but associated with increase in sedation and incidence of bradycardia.&#x0D; Conclusion We conclude that dexmedetomidine 50 mcg would be an appropriate dose as adjuvant to local anesthesia in brachial plexus block.

A triple blind, randomised, placebo controlled, add-on trial to assess the efficacy and safety of dexmedetomidine in facilitation of general anaesthesia in patients undergoing elective spine surgery

Background: Dexmedetomidine is a centrally acting sympatholytic drug acting as an agonist on alpha2 receptors. Of late, the drug has become popular in anaesthesia because of its sedative, analgesic and anti-adrenergic effects.&#x0D; Aims and Objectives: We conducted a single centre, randomised, placebo controlled, triple blinded add-on trial to assess the efficacy and safety of the drug as an adjuvant in general anaesthesia (GA) during elective spine surgery.&#x0D; Materials and Methods: Anaesthesia was induced and maintained using standard method in all the patients (N=60). Concomitantly, patients in the treatment arm (n=30) and control arm (n=30) were infused with dexmedetomidine and normal saline respectively. The anaesthetic sparing effect, hemodynamic stability, and adverse events of dexmedetomidine were assessed using pre-defined outcome parameters.&#x0D; Results: Anaesthetic Sparing Effect: Dexmedetomidine produced statistically significant reduction in the requirement of propofol and fentanyl during GA (p&lt;0.001). There was no significant difference in requirement of rocuronium (p=0.25). Hemodynamic Stability: The cardiovascular stimulation during surgery, in general, and during stress of artificial endotracheal access, in particular, were attenuated in the treatment arm. The heart rate (HR) and mean arterial pressure (MAP), in the control and treatment arm became greater and lesser than the baseline value respectively, at all the time points following induction. The HR and MAP remained close to baseline values during intubation and extubation in the treatment arm but surged significantly in the control arm (p&lt;0.001). Adverse Events: The number of episodes of hypotension, hypertension and bradycardia in the control arm was 1, 18 and 1 respectively. In the treatment arm, 2 episode each of hypotension and bradycardia and none of hypertension occurred.&#x0D; Conclusion: Dexmedetomidine, which is being increasingly used as an adjuvant in GA in various types of surgeries, also plays an auxiliary role in facilitation of GA in spine surgery. It decreases requirement of the primary anaesthetic agents, and also mitigates intra-operative cardiovascular instability without causing any significant adverse effect.

A Centrally Acting Antihypertensive, Clonidine, Sedates Patients Presenting With Acute Respiratory Distress Syndrome Evoked by Severe Acute Respiratory Syndrome-Coronavirus 2.

A Centrally Acting Antihypertensive, Clonidine, Sedates Patients Presenting With Acute Respiratory Distress Syndrome Evoked by Severe Acute Respiratory Syndrome-Coronavirus 2.

Effect of intravenous lignocaine infusion on the quality of emergence in patients undergoing transsphenoidal resection of pituitary tumors - A prospective, randomized controlled trial.

Background: Emergence from anesthesia is a critical step in patients undergoing transsphenoidal pituitary surgery (TSS). The cough suppressant and anesthetic sparing properties of lignocaine makes it a favorable option for smooth extubation and maintaining stable hemodynamics intraoperatively. We aimed to evaluate the effect of lignocaine infusion on the quality of emergence (QOE) and intraoperative hemodynamics in patients undergoing transsphenoidal resection of pituitary tumors.Methods: Fifty patients scheduled to undergo TSS were randomly divided into ligocaine group (n = 25), receiving 1.5 mg/kg bolus dose of lignocaine followed by continuous infusion of 1.5 mg/kg/h and saline group (n = 25). Patients assigned to the control group received equal volume of saline receiving equal volume of saline. The four emergence parameters (mean arterial pressure [MAP], heart rate (HR), cough, and agitation) were abbreviated into an aggregated score for QOE. Time to emergence and intraoperative hemodynamics were also recorded.Results: The QOE was not found to be different between the two groups (P = 0.294). Lignocaine did not increase the time to emergence (P = 0.166). The intraoperative HR and MAP were comparable between the two groups. A lower minimum alveolar concentration of desflurane was required in lignocaine group during insertion of nasal speculum (P = 0.018) and at the time of seller ridge dissection (P = 0.043) compared to the saline group.Conclusion: Intraoperative lignocaine infusion of 1.5 mg/kg/h did not significantly improve the QOE with respect to hemodynamics, cough, and emergence agitation in patients undergoing transsphenoidal resection of pituitary tumors.

Dexmedetomidine in Enhanced Recovery After Surgery (ERAS) Protocols for Postoperative Pain.

Purpose of ReviewEffective acute pain management has evolved considerably in recent years and is a primary area of focus in attempts to defend against the opioid epidemic. Persistent postsurgical pain (PPP) has an incidence of up to 30–50% and has negative outcome of quality of life and negative burden on individuals, family, and society. The 2016 American Society of Anesthesiologists (ASA) guidelines states that enhanced recovery after surgery (ERAS) forms an integral part of Perioperative Surgical Home (PSH) and is now recommended to use a multimodal opioid-sparing approach for management of postoperative pain. As such, dexmedetomidine is now being used as part of ERAS protocols along with regional nerve blocks and other medications, to create a satisfactory postoperative outcome with reduced opioid consumption in the Post anesthesia care unit (PACU).Recent FindingsDexmedetomidine, a selective alpha2 agonist, possesses analgesic effects and has a different mechanism of action when compared with opioids. When dexmedetomidine is initiated at the end of a procedure, it has a better hemodynamic stability and pain response than ropivacaine. Dexmedetomidine can be used as an adjuvant in epidurals with local anesthetic sparing effects. Its use during nerve blocks results in reduced postoperative pain. Also, local infiltration of IV dexmedetomidine is associated with earlier discharge from PACU.SummaryPerioperative use of dexmedetomidine has significantly improved postoperative outcomes when used as part of ERAS protocols. An in-depth review of the use of dexmedetomidine in ERAS protocols is presented for clinical anesthesiologists.

Controlled Hypotension for Functional Endoscopic Sinus Surgery: A Comparative study of Dexmedetomidine and Esmolol

Background: Functional endoscopic sinus surgery (FESS) requires effective control of bleeding for better visibility of the operating field and reduced risk of injury to the optic nerve or the internal carotid artery. Controlled hypotension is a technique used to limit intraoperative blood loss to provide the best possible field for surgery.&#x0D; Objectives: Our study is undertaken to evaluate the efficacy of dexmedetomidine as a hypotensive agent in comparison to esmolol in Functional Endoscopic Sinus Surgery (FESS).&#x0D; Methods: Sixty (60) patients 20 – 50 years of age, ASA I/II scheduled for FESS were randomly assigned to two equal groups of 30 patients each. Patients of group D received dexmedetomidine 1µg/kg over 10 min before induction of anesthesia followed by 0.4 – 0.8 µg/kg/hr infusion during maintenance and group E received esmolol loading dose 1mg/kg was infused over one min followed by 0.4 – 0.8 mg/kg/hr infusion during maintenance to maintain mean arterial blood pressure (MAP) between (55 – 65 mmHg). The surgical field was assessed using Average Category Scale and average blood loss was calculated. Hemodynamic variables (MAP, HR); intraoperative fentanyl consumption and total recovery from anesthesia (Aldrete’s score ≥9) were recorded. Sedation score was determined at 10, 20, 30, 40 &amp; 60 min after tracheal extubation and time to first analgesic demand was also recorded.&#x0D; Results:In both group D and group E reached the desired MAP (55–65 mmHg) with no inter group difference in MAP or HR. Mean intraoperative fentanyl consumption was significantly lower in group D than group E. Recovery time to achieved Aldrete’s score ≥9 were significantly lower in group E compared with group D.The sedation score were significantly lower in group E compared with group D at 10 minutes, 20 minutes and 30 minutes postoperatively. Time to first analgesic demand was significantly longer in group D.&#x0D; Conclusion: The result of this study showed that both dexmedetomidine and esmolol can be used as agents for controlled hypotension and are effective in providing ideal surgical field during FESS. But dexmedetomidine offers the advantage of inherent analgesic, sedative and anesthetic sparing effect.&#x0D; Bangladesh J Otorhinolaryngol; April 2018; 24(1): 37-49

Substitution of propofol for dexmedetomidine in the anaesthetic regimen does not ameliorate the post-operative cognitive decline in elderly patients

Background and Aims:Post-operative cognitive dysfunction (POCD) is a poorly understood complication particularly observed in elderly patients, with long-term poor outcome. The randomised study was to compare the incidence of POCD in elderly with bispectral index (BIS)-guided intra-operative use of either dexmedetomidine or propofol with sevoflurane.Methods:Eighty-seven patients, planned for non-cardiac surgery under general anaesthesia, were included between June 2017 and March 2018. After exclusion of 7 patients, remaining 80 patients were randomised into dexmedetomidine group and propofol group with 40 patients each. In both the groups, BIS-guided anaesthesia was provided. Cognitive function was assessed by an anaesthesiologist using a battery of neuropsychological tests at baseline pre-operatively, third and seventh day after surgery. The data were entered into a Microsoft Excel spreadsheet and analysis was performed using Statistical Package for Social Sciences (SPSS) version 21.Results:Propofol group had a non-significant lower incidence of POCD on third day and dexmedetomidine group showed decreased incidence of POCD on seventh day, accompanied by lower anaesthetic requirement (inhalational as well as intravenous) concomitant with delayed emergence with an acceptable BIS value.Conclusion:Dexmedetomidine appeared to be anaesthetic sparing as compared to propofol. BIS monitoring for titrating depth of anaesthesia and hence the anaesthetic exposure is an invaluable tool as compared to routine care anaesthesia for reducing POCD. The patients in both groups did not develop significant POCD until the seventh post-operative day.

A randomised controlled trial to evaluate the peri-operative role of intraoperative dexmedetomidine infusion in robotic-assisted laparoscopic oncosurgeries

Background:Robotic and minimal invasive surgeries pose challenges to the anaesthesiologists. Dexmedetomidine (dexmed), with distinct properties of sedation and analgesia has emerged as a promising drug. Our primary aim, in this double-blinded study, was to evaluate reduction in the intraoperative opioid requirement with the use of intravenous dexmed infusion. Secondary objectives included effect on intraoperative anaesthetic and postoperative analgesic requirement.Methodology:After approval from Ethics board and registration of the trial, 46 eligible patients planned for robotic oncosurgeries (abdomen) were included. As per computer generated randomisation chart, patients were randomised into either dexmed or saline group. Five minutes after insufflation of the abdomen, the study drug bolus—saline or dexmed (1 μg/kg) was given over 10 min and was followed by maintenance infusion (0.2 μg/kg/h) until release of pneumoperitoneum. Study drug titration, fentanyl boluses, and changes in minimum alveolar concentration (MAC) of inhalational agent were protocolised.Results:The mean intraoperative fentanyl requirement was significantly lower in the dexmed group 192.6 μg (±66.4) versus the saline group 260.7 μg (±88.6), P = 0.013. The MAC requirement of inhalational agent was significantly lower in the dexmed group. Intraoperative episodes of hypotension and bradycardia were similar in both groups. First analgesic request, 24 h postoperative pain scores and side effects profile were comparable in both groups.Conclusion:Intraoperative dexmed (bolus of 1 μg/kg followed by 0.2 μg/kg/h infusion) has an opioid and inhalational anaesthetic sparing role during robotic oncosurgeries. However, no benefit of the infusion is seen in the postoperative period.

Pharmacokinetics of dexmedetomidine during administration of vatinoxan in male neutered cats anesthetized with isoflurane

Dexmedetomidine is an alpha-2 adrenoceptor agonist, and vatinoxan is an alpha-2 antagonist believed to poorly cross the blood-brain barrier in cats. Dexmedetomidine-vatinoxan combinations are of interest in anesthetized cats because the anesthetic sparing effect of dexmedetomidine may be preserved while vatinoxan attenuates the adverse cardiovascular effects of dexmedetomidine. The aim of this study was to characterize the pharmacokinetics of dexmedetomidine in cats during administration of isoflurane and vatinoxan. Six healthy adult male castrated cats were anesthetized with isoflurane in oxygen. Vatinoxan was administered using a target-controlled infusion system intended to maintain a plasma concentration of 4 µg/ml. Dexmedetomidine, 35 µg/kg was administered intravenously over 5 min. Plasma dexmedetomidine and vatinoxan concentrations were measured at selected time points ranging from prior to 8 hr after dexmedetomidine administration using liquid chromatography/tandem mass spectrometry. Compartment models were fitted to the time-concentration data using nonlinear mixed-effect modeling. A three-compartment model best fitted the data. Typical value (% interindividual variability) for the three-compartment volumes (ml/kg), the metabolic clearance and the two intercompartment distribution clearances (ml min-1 kg-1 ) were 168 (259), 318 (35), 1,425 (18), 12.4 (31), 39.1 (18), and 29.6 (17), respectively. Mean ± standard deviation plasma vatinoxan concentration was 2.6 ± 0.6 µg/ml.

Paravertebral Block Versus Intercostal Nerve Block in Non-Intubated Uniportal Video-Assisted Thoracoscopic Surgery: A Randomised Controlled Trial

Non-intubated uniportal video-assisted thoracoscopic surgery (VATS) has been reported to be safe and feasible for patients with various thoracic diseases, including those who have respiratory dysfunction. This study examined the anaesthetic and analgesic sparing effects of either paravertebral block or intercostal nerve block on the non-intubated technique with spontaneous ventilation in patients under general anaesthesia (GA) using a supraglottic airway device. The primary aim was to compare the anaesthetic sparing effect of paravertebral block versus intercostal nerve block in non-intubated GA with airway support via a supraglottic airway device during VATS surgery. The secondary aim was to compare the recovery characters and postoperative outcomes of the patients. The study included 105 patients with American Society of Anesthesiologists (ASA) physical status II-III who had video-assisted thoracoscopy without endotracheal intubation and using a laryngeal airway. The patients were divided into three groups; each group consisted of 35 patients. Group I (35 patients): control group received only GA. Group 2 (35 patients): received a single-shot paravertebral block before induction of the GA. Group 3 (35 patients): received thoracoscopic intercostal block infiltration after induction of anaesthesia from the third to the eighth intercostal nerve block, in addition to intrathoracic vagal block. Heart rate, mean arterial pressure (MAP), and oxygen saturation were recorded before induction of GA (T0), after induction of GA (T1), 20 minutes later (T2), and before the end of the surgical procedure (T3). Heart rate was significantly lower in Groups 2 and 3 compared with Group 1, and lower in Group 2 compared with Group 3. The MAP was significantly lower in Groups 2 and 3 compared with Group 1, and there was no significant difference between Groups 2 and 3. Oxygen saturation was significantly higher in Group 2 and in Group 3 compared with Group 1 and there was no significance difference between Groups 2 and 3. Expiratory fraction of sevoflurane (Ef sevo) was significantly lower in Groups 2 and 3 compared with Group 1, with no difference between Group 2 and 3. Groups 2 and 3 had lower fentanyl requirements, time to spontaneous eye movement, time to spontaneous arm movement, time to purposeful movement, and time to laryngeal mask removal than Group 1. Regional anaesthesia by either preoperative paravertebral block or thoracoscopic intercostal nerve block with ipsilateral vagal block provided an anaesthetic sparing effect, guided by lower Ef sevo concentration, with comparable bi-spectral index in patients undergoing uniportal thoracoscopic surgery.

Serial Blood Glucose Level Estimation to Assess the Attenuation of Metabolic and Hemodynamic Stress Responses with Dexmedetomidine Infusion during Laparoscopic Surgery - A Randomized Control Study

Background: Laparoscopic surgery under general anaesthesia activates the neurohumoral stress responses thereby causing release of significant amount of catecholamines into the tissue. We hypothesized that intraoperative dexmedetomidine infusion would attenuate the metabolic and hemodynamic changes during laparoscopic surgery which could be assessed by estimating the serial blood sugar level. Subjects and Methods: Sixty adult consenting patients undergoing laparoscopic surgery were enrolled. Patients were randomized into two equal groups of 30 patients each. Patients of Group D received loading dose of dexmedetomidine 1µg/kg over 10 min, followed by dexmedetomidine infusion at rate of 0.5µg/kg/h while patients of Group C received equal volume of normal saline. Primary end points were changes in heart rate, blood pressure, electrocardiogram, emergence time and serial blood glucose levels. Any adverse effects related to dexmedetomidine or anesthetic technique, were noted as secondary outcome. Results: Patients of Group D showed comparatively lower intraoperative heart rate and mean arterial blood pressure with no significant changes in cardiac rhythm. The blood glucose concentration showed 20% increase after surgery in patients of Group D versus 35% increase in patients of Group C, with statistically significant difference. The emergence time in patients of Group C was significantly lower when compared to patients of Group D. Conclusion: Dexmedetomidine infusion has effectively attenuated the metabolic and hemodynamic changes during laparoscopic surgery with inherent advantages of analgesia, sedation and anaesthetic sparing effects.

The in vivo specificity of synaptic G\u03b2 and G\u03b3 subunits to the \u03b12a adrenergic receptor at CNS synapses

G proteins are major transducers of signals from G-protein coupled receptors (GPCRs). They are made up of α, β, and γ subunits, with 16 Gα, 5 Gβ and 12 Gγ subunits. Though much is known about the specificity of Gα subunits, the specificity of Gβγs activated by a given GPCR and that activate each effector in vivo is not known. Here, we examined the in vivo Gβγ specificity of presynaptic α2a-adrenergic receptors (α2aARs) in both adrenergic (auto-α2aARs) and non-adrenergic neurons (hetero-α2aARs) for the first time. With a quantitative MRM proteomic analysis of neuronal Gβ and Gγ subunits, and co-immunoprecipitation of tagged α2aARs from mouse models including transgenic FLAG-α2aARs and knock-in HA-α2aARs, we investigated the in vivo specificity of Gβ and Gγ subunits to auto-α2aARs and hetero-α2aARs activated with epinephrine to understand the role of Gβγ specificity in diverse physiological functions such as anesthetic sparing, and working memory enhancement. We detected Gβ2, Gγ2, Gγ3, and Gγ4 with activated auto α2aARs, whereas we found Gβ4 and Gγ12 preferentially interacted with activated hetero-α2aARs. Further understanding of in vivo Gβγ specificity to various GPCRs offers new insights into the multiplicity of genes for Gβ and Gγ, and the mechanisms underlying GPCR signaling through Gβγ subunits.

Controlled Hypotension for Functional Endoscopic Sinus Surgery: A Comparative study between Dexmedetomidine versus Esmolol

Background: Functional endoscopic sinus surgery (FESS) requires effective control of bleeding forbetter visibility of the operating field and reduced risk of injury to the optic nerve or the internal carotidartery. Controlled hypotension is a technique used to limit intraoperative blood loss to provide the bestpossible field for surgery. Objectives: Our study is undertaken to evaluate the efficacy of dexmedetomidine as a hypotensive agentin comparison to esmolol in Functional Endoscopic Sinus Surgery (FESS). Method: Sixty (60) patients 20 – 50 years of age, ASA I/II scheduled for FESS were equally randomlyassigned to two equal groups of 30 patients each. Patients of group D received dexmedetomidine 1μg/kgover 10 min before induction of anesthesia followed by 0.4 – 0.8 μg/kg/hr infusion during maintenanceand group E received esmolol loading dose 1mg/kg was infused over one min followed by 0.4 – 0.8 mg/kg/hr infusion during maintenance to maintain mean arterial blood pressure (MAP) between (55 – 65mmHg). The surgical field was assessed using Average Category Scale and average blood loss wascalculated. Hemodynamic variables (MAP, HR); intraoperative fentanyl consumption and total recoveryfrom anesthesia (Aldrete’s score e”9) were recorded. Sedation score was determined at 10, 20, 30, 40 &amp; 60min after tracheal extubation and time to first analgesic demand was also recorded. Results: In both group D and group E reached the desired MAP (55 – 65 mmHg) with no intergroupdifference in MAP or HR. Mean intraoperative fentanyl consumption was significantly lower in group Dthan group E. Recovery time to achieved Aldrete’s score e”9 were significantly lower in group E comparedwith group D. The sedation score were significantly lower in group E compared with group D at 10minutes, 20 minutes and 30 minutes postoperatively. Time to first analgesic demand was significantlylonger in group D. Conclusion: The result of this study showed that both dexmedetomidine and esmolol can be used asagents for controlled hypotension and are effective in providing ideal surgical field during FESS. Butdexmedetomidine offers the advantage of inherent analgesic, sedative and anesthetic sparing effect. JBSA 2018; 31(2): 67-74

Modulation of Synaptic transmission: Quantitative analysis of Gβγ specificity to adrenergic α2a receptor and SNARE.

Modulation of neurotransmitter exocytosis by activated Gi/o coupled G‐protein coupled receptors (GPCRs) is a universal regulatory mechanism used both to avoid overstimulation and to influence circuitry. One of the known modulation mechanisms is Gβγ interaction with soluble N‐ethylmaleimide‐sensitive factor attachment protein receptor (SNARE). There are 5 Gβ and 12 Gγ subunits, but specific Gβγs activated by a given GPCR and the specificity to effectors in vivo are not known. Presynaptic α2a‐adrenergic receptors (α2aARs) in both adrenergic (auto α2aARs) and non‐adrenergic neurons (hetero α2aARs) inhibit neurotransmitter release and affect various physiological functions such as anesthetic sparing and working memory enhancement. With a quantitative MRM proteomic analysis of neuronal Gβ and Gγ subunits to detect neuronal Gβ and Gγ subunits, several mouse models including transgenic Flag‐α2aARs, knock‐in HA‐α2aARs, and other biochemical techniques such as co‐immunoprecipitation, we investigate the specificity of Gβ and Gγ subunits to α2aARs in both adrenergic(auto α2aARs) and non‐adrenergic neurons (hetero α2aARs), and SNARE in presence of epinephrine. Gβ2, Gγ2, Gγ3, and Gγ4 preferentially interact with activated auto α2aARs while Gβ4 and Gγ12 preferentially interact with activated hetero α2aARs. We also detect a subset of Gβ and Gγ subunits interacting with SNARE upon α2aARs activation. Further understanding of Gβγ specificity on its downstream signaling, especially Gβγ‐SNARE interaction, offers new insights into the normal functioning of the brain and lead to an identification of potential pathophysiological states in which the Gβγ‐SNARE interaction may be dysregulated. These studies yield additional insights into Gi/o‐coupled GPCR‐mediated regulation of exocytosis.Support or Funding InformationThis work was supported by the National Institutes of Health (EY10291, MH101679, DK109204, and T32 GM07628).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.