Sevoflurane Consumption Research Articles

Trends in volatile anesthetic sevoflurane and desflurane usage and its impact on carbon emissions: A six-year audit at National Taiwan University Hospital (2018–2023)

This short communication presents an audit of anesthetic gas usage at National Taiwan University Hospital from 2018 to 2023. Using descriptive statistics and trend analysis, the data reveals trends in the consumption of sevoflurane and desflurane, associated costs, and their corresponding carbon emissions. A significant decrease in desflurane usage contributed to a 42.4% reduction in carbon dioxide equivalent (CO2e) emissions per general anesthesia case from 2018 to 2023. The findings underscore the importance of sustainable practices in anesthesia to align with global efforts to reduce carbon emissions.

Inhalational anaesthetic agent consumption within a multidisciplinary veterinary teaching hospital: an environmental audit

Inhalational anaesthetic agents are routinely used in veterinary anaesthesia practices, yet their consumption contributes significantly to greenhouse gas emissions and environmental impact. We conducted a 55-day observational study at a veterinary teaching hospital in Switzerland, monitoring isoflurane and sevoflurane consumption across small, equine and farm animal clinics and analysed the resulting environmental impact. Results revealed that in total, 9.36 L of isoflurane and 1.27 L of sevoflurane were used to anaesthetise 409 animals across 1,489 h. Consumption rates varied among species, with small and farm animals ranging between 8.7 and 13 mL/h, while equine anaesthesia exhibited a higher rate, 41.2 mL/h. Corresponding to 7.36 tonnes of carbon dioxide equivalent in total environmental emissions or between 2.4 and 31.3 kg of carbon dioxide equivalent per hour. Comparison to human anaesthesia settings showed comparable consumption rates to small animals, suggesting shared environmental implications, albeit on a smaller scale. This research highlights the importance of continued evaluation of veterinary anaesthesia practices to balance patient safety with environmental stewardship; potential mitigation strategies are explored and discussed.

The effect of preemptive retrolaminar block on lumbar spinal decompression surgery

PurposeSpinal decompression surgery causes severe pain. Retrolaminar block (RLB) is block, which is done by infiltration of local anesthetic to block spinal nerves between the lamina and superior costotransversospinalis muscle. The primary aim of this study is to evaluate the effectiveness of RLB on postoperative analgesia in patients undergoing spinal surgery. Secondary aims are effects on additional anesthetic and analgesic consumption.MethodsThe sixty (60) patients who underwent lumbar spinal surgery between May 2020 and May 2021 under general anesthesia with or without applied preemptive RLB for postoperative analgesia were included in this prospective observational study. Group I received ultrasound-guided preemptive RLB. In Group II, no intervention was performed. Postoperative VAS scores were compared in groups as primary outcome, perioperative additional anesthetic and analgesic needs were compared as secondary outcome.ResultsThere was a significant difference between the groups in favor of the RLB group in terms of postoperative VAS scores at rest [1.33 (0.33–3.509)] and movement [2.40 (1.20–4.00)] (p < 0.001). Perioperative sevoflurane consumption was significantly low in block group (p < 0.001). Postoperative tramadol consumption was lower in Group I compared with Group II [Group 1: 200 (100–300); Group 2: 37.5 (0–200); p < 0.001].ConclusionPreemptive RLB may be used to reduce patients' pain in lumbar decompression surgery as well as to be part of a multimodal analgesia and anesthesia regimen to reduce anesthetic and analgesic drug consumption.Trial registration numberClinicalTrials.gov (No. NCT04209907).

Effect of bispectral index on intra-operative awareness: A meta-analysis of randomized controlled studies.

Randomized controlled trials (RCTs) investigating the efficacy of bispectral index (BIS) to reduce intra-operative awareness (IOA) have reported conflicting results. The purpose of this meta-analysis is to consolidate results from RCTs to assess the efficacy of BIS in reducing IOA when compared to controls. Secondary outcomes included time to extubation, time to spontaneous and/or verbal eye opening, PACU discharge time, and utilization of inhaled anesthetics. RCTs which reported on one of the primary and/or secondary outcomes were included. Literature search utilized keywords "randomized control trial" and "intraoperative awareness." Meta-analysis was performed using RevMan 5. Twenty-seven RCTs were included in the study with a total of 35,585 patients, with 18,146 patients in the BIS and 17,439 in the control group. Eighteen of 14,062 patients (0.12%) and 42 of 16,765 (0.25%) reported definite IOA in the BIS and control group, respectively, with no statistically significant difference. BIS was effective in reducing the time to spontaneous eye opening by an average of 1.3 minutes and the time to extubation by an average of 1.97 minutes. There was no difference in PACU discharge times among the groups. There was a significant decrease in consumption of sevoflurane but no difference in desflurane and propofol compared to the control group. While BIS monitoring results in decreased incidence of intra-operative awareness by half, it was not statistically significant. BIS provides modest benefits with regard to reducing the time to extubation, the time to spontaneous eye opening, and consumption of sevoflurane.Level of evidence: I.

Efficiency of CONTRAfluran™ in reducing sevoflurane pollution from maintenance anaesthesia in minimal flow end-tidal control mode for laparoscopic surgery: Efficiency of CONTRAfluran™.

Recommendations exist that aim to mitigate the substantial ecological impact of anaesthesia. One option is to use anaesthetic gas capturing technology at anaesthesia workstation exhausts to harvest and recycle volatile agents. However, the efficiency of such technology is mainly unverified in vivo. The efficiency of CONTRAfluran™ in capturing sevoflurane from an anaesthesia workstation exhaust (when set to minimal flow and end-tidal control mode) was evaluated in 70 adult patients scheduled for general or bariatric laparoscopic surgery. The weight of the sevoflurane vaporiser and CONTRAfluran canister was measured before and after each case, to calculate total sevoflurane consumption and retention. Retention was measured after the minimal flow maintenance phase and after the high flow washout phase. The total retention efficiency was the fraction of all consumed sevoflurane captured by the CONTRAfluran canister. The primary objective was to examine the retention efficiency of CONTRAfluran in a clinical surgical setting, where all feasible strategies to minimise sevoflurane consumption and optimise the efficacy of CONTRAfluran were utilised. The secondary objective was to analyse the correlation between mass transfer and the duration of the case. Mean (SD) volume of sevoflurane captured using CONTRAfluran was 4.82 (1.41) ml, representing 45% (95%CI 42-48%) of all sevoflurane administered. The highest amount of retention was found during the washout phase. Retention efficiency did not correlate with the duration of the case. Over half of the sevoflurane administered was not captured by the CONTRAfluran canister when minimal flow techniques were used, likely due to residual accumulation of sevoflurane in the patient after tracheal extubation or, to a lesser extent, due to ventilation system leakage. However, as every prevented emission is commendable, CONTRAfluran may be a potentially valuable tool for reducing the environmental footprint of sevoflurane-based anaesthesia.

Effect of Dexmedetomidine Premedication on Sevoflurane Requirement using BIS during General Anaesthesia in Laparoscopic Cholecystectomy

Background: Dexmedetomidine is a highly selective α2-adrenoreceptor agonist with sedative, anxiolytic and analgesic properties without any respiratory depression. It decreases the requirement of volatile anaesthetics with better hemodynamic stability in surgical patients. We avoided the risk of awareness under anaesthesia by using Bispectral index. Aims: To evaluate the efficacy of Dexmedetomidine pre-medication on Sevoflurane requirement and to assess the haemodynamic stability during elective laparoscopic cholecystectomy surgeries. Methods: Randomized double-blind control study. Design: Forty eight patients were randomly allocated into two groups. Group A received saline infusion and Group 2 received Dexmedetomidine infusion in a dose of 1µg/kg over 15 min before induction. Vital parameters and bispectral index were noted throughout the surgery. Patients were induced and intubated as per the standard protocol and maintained with Oxygen &amp; Nitrous oxide (1 litre Oxygen + 2 litre Nitrous oxide) with Sevoflurane concentration adjusted to achieve BIS values of 45–55. Demographic profile, hemodynamic parameters total Sevoflurane consumption were noted. Statistical Analysis: Statistical analysis was performed using SPSS software version 22.0. Percentage analysis was done for qualitative data. Parametric data were compared using an unpaired t-test. Nonparametric data were compared with Fisher’s exact test or Chi-square test. Results: Mean Sevoflurane consumption in Group A and Group B were 0.379 ± 0.10, 0.169 ± 0.05 ml/min respectively with P&lt;0.001 which was statistically significant. A 55.4% reduction in Sevoflurane consumption was found in patients receiving Dexmedetomidine premedication. Conclusions: Dexmedetomidine premedication is useful to reducing Sevoflurane consumption during general anesthesia and it provides better haemodynamic stability.

Preventing Prolonged Times to Awakening While Mitigating the Risk of Patient Awareness: Gas Man Computer Simulations of Sevoflurane Consumption From Brief, High Fresh Gas Flow Before the End of Surgery.

Prolonged times to tracheal extubation are associated with adverse patient and economic outcomes. We simulated awakening patients from sevoflurane after long-duration surgery at 2% end-tidal concentration, 1.0 minimum alveolar concentration (MAC) in a 40-year-old. Our end-of-surgery target was 0.5 MAC, the Michigan Awareness Control Study's threshold for intraoperative alerts. Consider an anesthetist who uses a 1 liter/minute gas flow until surgery ends. During surgical closure, the inspired sevoflurane concentration isreduced from 2.05% to0.62% (i.e., MAC-awake). The estimated time to reach 0.5 MAC is 28 minutes. From a previous study, 28 minutes exceeded ≥95% of surgical closure times for all 244 distinct surgical procedures (N=23,343 cases). Alternatively, the anesthetist uses 8 liters/minute gas flow with the vaporizer atMAC-awake for 1.8 minutes, which reduces the end-tidal concentration to 0.5MAC. The anesthetist then increases the vaporizer to keep end-tidal 0.5 MAC until the surgery ends. An additional simulation shows that, compared with simulated end-tidal agent feedback control, this approach consumed 0.45 mL extra agent. Simulation results are the same for an 80-year-old patient. The extra 0.45 mL has a global warming potential comparable to driving 26 seconds at 40 kilometers (25 miles) per hour, comparable to route modification to avoid potential roadway hazards.

Impact on Anesthetic Agent Consumption After Autonomic Neural Blockade as Part of a Combined Anesthesia Protocol: A Randomized Clinical Trial.

The intraoperative autonomic neural blockade (ANB) was found safe and effective in controlling pain and associated symptoms and reducing analgesic consumption after laparoscopic sleeve gastrectomy (LSG). This study evaluated whether ANB performed at the outset of LSG reduces anesthetic consumption and promotes hemodynamic stability. This prospective, double-blinded, randomized trial involved patients undergoing LSG in 2 high-volume institutions. Patients were randomized to receive ANB either at the onset or the end of the procedure. The primary outcome measure was the consumption of remifentanil and sevoflurane. Secondary outcomes included Aldrete scale score differences in the recovery room and hemodynamic stability during the surgery. In total, 80 patients (40 in the ANB at the onset group and 40 in the control group) were included for analysis. The consumption of remifentanil was significantly lower in the onset group compared to the control group (mean difference -0.04 mcg/kg/min, 95% confidence interval [CI], -0.06 to -0.02; P < .0001). There were no differences in the Aldrete scale scores between the 2 groups. Mean heart rate (HR) and mean arterial pressure (MAP) were also significantly less during surgery in the ANB at the onset group. No complications related to the ANB occurred. Performing ANB at the onset of LSG is a safe and effective approach that reduces remifentanil consumption and promotes hemodynamic stability during the procedure. This technique holds promise for optimizing anesthesia management in LSG and other minimally invasive surgeries.

Is the reduced risk of post-operative nausea and vomiting in low flow anesthesia applications associated with pre-operative neutrophil/lymphocyte ratio values?

Background/Aim: Post-operative nausea and vomiting (PONV) are defined as nausea and/or vomiting occurring within the first 24 h after surgery and are often observed in the first 2 h after surgery. Only a few previous studies on the use of low fresh gas flow that reduces inhaler agent consumption in laparoscopic cholecystectomy patients at high risk of PONV have been published. Our study aimed to determine the incidence of PONV in the first 30 min and again at 24 h in cases of laparoscopic cholecystectomy in which we applied low fresh gas flow (1 L/min). In addition, we wanted to predict whether the pre-operative neutrophil/lymphocyte ratio (NLR) ≥2 is a risk factor for PONV in our patients to whom we applied low fresh gas flow. Methods: For our prospective cohort study, 80 cases between the ages of 18 and 65, had American Society of Anesthesiologists (ASA) scores of I and II, and who had been scheduled to undergo elective laparoscopic cholecystectomy were included in the study. The NLR limit (calculated by dividing the neutrophil count obtained from the complete blood count before surgery by the lymphocyte count) calculated in the pre-operative period after a patient’s informed consent was obtained was accepted as 2 [5]. Patients were classified into two groups: (1) NLR-I with NLR &lt;2 and (2) NLR-II with NLR ≥2. Premedication was not used in either group. Results: A total of 80 patients were included in the study. They were divided into two groups for classification purposes: (1) NLR-I (n=40) and (2) NLR-II (n=40). The characteristics of the patients in both groups, such as gender distribution, ASA scores, smoking status, mean age, and body mass index (BMI) values, were not different. Sevoflurane consumption in the groups was similar (P=0.169). The time required to complete surgery was longer in the NLR-II group (P=0.025). Nausea/vomiting and antiemetic use were similar in the NLR-I and NLR-II groups in which low fresh gas flow was applied in the first 30 min and 24 h (P=0.500). Although nausea/vomiting was more common in the female and non-smoking group in the first 30 min and 24 h, it was not statistically significantly different from males and smoking groups (P=0.325). However, nausea/vomiting was more common and significantly different in the ASA II versus the ASA I group (P=0.046). The time required to complete surgery was longer, and sevoflurane consumption was higher in patients with nausea and vomiting (P=0.001). Conclusions: Pre-operative NLR as classified by the two groups was not associated with an increase in the risk of PONV in patients to whom we applied low fresh gas flow. A decrease in sevoflurane consumption due to low fresh gas flow may lead to a reduction in the risk of PONV in at-risk patients.

The effect of erector spinae plane block on fentanyl consumption during open abdominal hysterectomy: a randomised controlled study

BackgroundPerioperative analgesia is very important during an abdominal hysterectomy. Determining the impact of the erector spinae plane block (ESPB) on patients undergoing an open abdominal hysterectomy while under general anesthesia was our aim.MethodsIn order to create equal groups, 100 patients who underwent elective open abdominal hysterectomies under general anesthesia were enlisted. The preoperative bilateral ESPB with 20 ml of bupivacaine 0.25% was administered to the ESPB group (n = 50). The same procedure was performed on the control group (n = 50), but they received a 20-ml saline injection instead. The primary outcome is the total amount of fentanyl consumed during surgery.ResultsWe found that the mean (SD) intraoperative fentanyl consumption was significantly lower in the ESPB group than in the control group (82.9 (27.4) g vs. 148.5 (44.8) g, with a 95% CI = -80.3 to -50.8; p 0.001). Likewise, mean (SD) postoperative fentanyl consumption was significantly lower in the ESPB group than in the control group (442.4 (17.8) g vs. 477.9 (10.4) g, with a 95% CI = -41.3 to -29.7; p 0.001). On the other hand, there is no statistically significant difference between the two study groups regarding sevoflurane consumption (89.2 (19.5) ml vs. 92.4 (15.3) ml, with a 95% CI = -10.1 to 3.8; p 0.4).We documented that during the post-operative period (0–24 h), VAS scores at rest were, on average, 1.03 units lower in the ESPB group (estimate = -1.03, 95% CI = -1.16-(-0.86), t = -14.9, p-value 0.001), and VAS scores during cough were, on average, 1.07 units lower in the ESPB group (estimate = -1.07, 95% CI = -1.21-(-0.93), t = -14.8, p-value 0.001).ConclusionBilateral ESPB can be utilized as an adjuvant method to reduce intraoperative fentanyl consumption and enhance postoperative pain control in patients undergoing open total abdominal hysterectomy under general anesthesia. It is effective, secure, and little obtrusive.Trial registrationNo protocol revisions or study amendments have been made since the trial's inception, according to the information on ClinicalTrials.gov (NCT05072184; principal investigator: Mohamed Ahmed Hamed; date of registration: October 28, 2021).

Effect of Use of Entropy Monitoring on Consumption of Sevoflurane Inhalational Agent in Patients Undergoing Off-Pump Coronary Artery Bypass Graft Surgery: A Randomized, Double Blinded, Controlled Study

Background: Monitoring the depth of Anesthesia using Entropy modality is essential and resourceful as it allows for more accurate hypnotic drug administration and decreased anesthetic drug consumption and shortens the recovery time. This study was performed to evaluate the effect of entropy monitoring on Sevoflurane consumption in patients undergoing Off Pump Coronary Artery Bypass Graft Surgery.&#x0D; Methods: A total of 60 patients of ages between 40 – 70 years and of either sex with American Society of Anesthesiologist (ASA) grade 2 and 3, planned for Off Pump Coronary Artery Bypass Graft Surgery were randomly allocated to two groups in this Randomized Controlled Trial. In the control group i.e. Group B, Sevoflurane was titrated according to changes in clinical parameters (Heart Rate (HR) and Blood Pressure (BP) changes within 20% of baseline values) and in the study group i.e. Group A, Sevoflurane was titrated to maintain State Entropy (SE) values between 40-60 accordingly. Response Entropy (RE) and State Entropy (SE) values were continuously recorded in both the groups but were displayed on the monitor only in the study group and were not displayed to the anesthesiologist in the control group. The entropy values, Sevoflurane Consumption and recovery times were compared amongst the two groups. Patients in both the groups were ventilated on Volume Control Mode of ventilator with 100% oxygen @ 2L/min.&#x0D; Results: There were no significant results in terms of age, sex, ASA Grade and NYHA Grade amongst the two groups. Sevoflurane consumption and time of recovery were significantly reduced in the study group i.e. Group A than the Control group i.e. Group B (p value &lt;0.001; Sevoflurane consumption: 7.03±0.67 ml/hr vs 12.42±0.68 ml/hr; Recovery Time 6.47±0.65 hr vs 12.05±1.11 hr). Response and State Entropy values were lower in the control group than the study group (p &lt; 0.001) during the maintenance phase of anesthesia. Systolic Blood Pressure values during skin incision, sternotomy and at the time of completion of all grafts were significantly lower in study group as compared to the control group.&#x0D; Conclusion: Monitoring the Depth of Anesthesia using Entropy Monitoring leads to significant reduction in Sevoflurane consumption and significant faster recovery rate from surgery.

Effects of automatic gas control on sevoflurane gas monitor and recovery during pancreatico-duodenectomy operation: prospective randomized study

ABSTRACT Background The aim of the study was to evaluate the effect of automatic gas control (AGC) on sevoflurane gas monitoring, safety, and recovery of patients during pancreatico-duodenectomy operation. Methods Forty patients scheduled for the pancreatico-duodenectomy operation were allocated into group I manual gas control group (MGC, n = 20) and group II AGC (n = 20) group. In (the MGC group): The vaporizer set ranged from 3 to 5% Sevoflurane until reaching 1 MAC, fresh gas flow (FGF) 1–2 L/min, and FiO2 of 0.4 was set. In (the AGC group): Set target FiO2 of 0.4, end-tidal anesthetic agent (EtSev was set to 1.5–2%) with safely ventilate the patient with an FGF down to 0.3 liters per minute. Hemodynamics, anesthesia gas analysis (FiSev, EtSev, FiO2, and EtO2), total gas consumption, extubation time, incidence of perioperative hypercapnia, hypoxia, and accidental awareness were recorded. Results The volume of sevoflurane administered in the MGC group was in a mean ± standard deviation of 81.20 ± 16.47 ml which was statistically significantly greater than that administered in the AGC group (58.80 ± 10.54), P ≤ 0.001. ETSevo, FISevo, and the EtO2 were significantly larger in the MGC group than in the AGC group. The extubation time was statistically prolonged in the MGC group than in the AGC group (14.10 ± 4.75 versus 7.70 ± 1.59 min, P < 0.001). No patient developed hypoxia, hypercapnia, or awareness in both groups. Conclusion AGC maintained the targeted end-tidal sevoflurane concentration with the least sevoflurane consumption. It reduced the manual adjustment of delivered sevoflurane and oxygen. General anesthesia with manual and AGC is safe and maintains hemodynamic stability.

Effects of bilateral transmucosal sphenopalatine ganglion block on intraoperative anesthetic requirements and recovery profile in children undergoing palatoplasty under general anesthesia.

Sphenopalatine ganglion block (SPGB) given as injection provides excellent perioperative analgesia during palatoplasty. Our objectives were to assess the effect of transmucosal SPGB on anesthetic requirements, intraoperative hemodynamics, recovery time, and emergence delirium in children undergoing palatoplasty. This prospective, randomized study was conducted in 30 children with cleft palate undergoing palatoplasty, divided into two equal groups. After induction and intubation, patients in Group B received bilateral SPGB using cotton-tipped applicators soaked in 2% lignocaine, which were passed through both the nares, and the distal tip was positioned just superior to middle turbinate and anterior to pterygopalatine fossa and sphenopalatine ganglion. In Group C, saline-soaked cotton applicators were used. All patients received general anesthesia as per a standardized protocol. Intraoperative heart rate, mean arterial pressure, the requirement of anesthetics, extubation time, and emergence delirium were compared. Compared with Group C, patients in Group B had significantly lower sevoflurane consumption (17.2 ± 2.6 vs. 27.5 ± 5.0mL, P < 0.001) and fentanyl consumption (2.2 ± 0.5 vs. 3.2 ± 0.6 μ/kg, P < 0.001).The extubation time was significantly shorter in Group B (3.9 ± 0.7 vs. 9.5 ± 1.6 minutes, P < 0.001). PAED (Pediatric Anesthesia Emergence Delirium Scale) scores at 5and 10 minutes were significantly higher in Group C (P < 0.001). Intraoperative heart rate was significantly higher in Group C. Group C had significantly higher mean arterial pressure at 15, 60, and 75 minutes. Preoperative, SPGB administered by mucosal application of local anesthetic significantly reduced sevoflurane and fentanyl requirements, with stable hemodynamics, quicker recovery, and less emergence delirium in children undergoing palatoplasty.

Opioid-Sparing Analgesic Effects from Interscalene Block Impact Anesthetic Management During Shoulder Arthroscopy: A Retrospective Observational Study.

Ultrasound-guided interscalene nerve block (UISB) is commonly used to alleviate postoperative pain during shoulder arthroscopy. This retrospective observational study aimed to evaluate the intraoperative advantages and analgesic effects of preoperative UISB. In this retrospective observational study, a total of 170 patients underwent shoulder arthroscopy at a tertiary medical center in southern Taiwan throughout 2019. After applying the exclusion criteria, 142 of these cases were included, with 74 and 68 in the UISB group and control groups, respectively. The primary outcome was the evaluation of intraoperative morphine milligram equivalent (MME) consumption. Secondary outcomes were sevoflurane consumption, the use of intraoperative antihypertensive drugs, and postoperative visual analog scale (VAS) scores in the post-anesthesia care unit (PACU) and in the ward at 24 h after surgery. Preoperative UISB effectively reduced opioids and volatile gases during surgery, supported by a 48.1% and 14.8% reduction in the median intraoperative MME and sevoflurane concentrations, respectively, and showed less need for antihypertensive drugs. The preoperative UISB group also showed significantly better performance on the VAS in both the PACU and ward. Taken together, the preoperative UISB reduced not only intraoperative MME and sevoflurane consumption but also had satisfactory VAS scores in both the PACU and ward without any symptomatic respiratory complications. In summary, preoperative UISB is a reliable adjuvant analgesic technique and a key factor in achieving opioid-sparing and sevoflurane-sparing anesthesia and multimodal analgesia during shoulder arthroscopy.

Prospective comparative analysis of intraoperative and postoperative anesthetic and analgesic effect of ultrasound-guided pectoral with serratus anterior plane block versus thoracic paravertebral versus erector spinae blocks in breast oncosurgeries

Abstract Aims and Objectives: Different regional anesthetic techniques have been described and are frequently used in breast cancer surgeries to provide efficient pain management and reduce the use of opioids. This study’s main goal was to use pain scores to compare the postoperative analgesic effectiveness of pectoral nerve (PECS 1) block with serratus anterior plane (SAP) block, thoracic paravertebral (TPV) block, and erector spinae plane (ESP) block. Comparing the needs for intraoperative analgesia and postoperative anesthesia was one of the secondary goals. Methods: After institutional ethical committee approval and after prospectively registering this trial with the Clinical Trials Registry of India, 25 patients were randomized and enrolled in each group (Group 1 – PECS 1 and SAP block, Group 2 – TPV group, and Group 3 – ESP group). Standard general anesthesia was administered to all the patients and the blocks, as per randomization were performed before anesthesia induction. Results: The demographic characteristics, intraoperative opioid and sevoflurane consumption, and requirement of rescue analgesia were comparable between the three groups. Pain scores at 0 and 6 h were significantly less in the TPV group when compared to the ESP group and PECS 1 with the SAP group (P = 0.005 and P = 0.006, respectively). Pain scores at 12 and 24 h were comparable between three groups. Conclusion: TPV block provides significantly better pain scores at 0 and 6 h, with comparable pain scores at 12 and 24 h, compared to PECS 1 with SAP block and ESP block with comparable adverse events.

Impact of Dexmedetomidine Infusion during Functional Endoscopic Sinus Surgery: A Randomised Controlled Trial

Introduction: Functional Endoscopic Sinus Surgery (FESS) requires a surgical field with minimal bleeding, and numerous pharmacological agents have been used to achieve this. Dexmedetomidine has been widely used as a sedative, analgesic, and as a supplement to general anaesthesia. It has been found to decrease norepinephrine release, thereby decreasing heart rate (HR) and blood pressure. These properties, along with its opioid-sparing analgesic effects, make it an attractive drug to use during FESS. Aim: The aim of this study was to determine if dexmedetomidine infusion during FESS improves the visibility of the surgical field, provides stable haemodynamics, and alters the consumption of sevoflurane and other anaesthetic agents. Materials and Methods: This randomised, double-blinded controlled trial was conducted at the Otorhinolaryngology Operation Theatre, BYL Nair Charitable Hospital, Mumbai, India, from July 2018 to December 2019. The study included 100 patients of either sex, with American Society of Anaesthesiologists (ASA) I and II classification, aged 18-55 years, who were randomly divided into two groups. Group D received a dexmedetomidine infusion (0.5 mcg/kg/hour), while group C (control group) received a saline infusion. Haemodynamic parameters, Minimum Alveolar Concentration (MAC) of sevoflurane, surgeon’s grading of the operative field, and the requirement of additional hypotensive agents were compared. Statistical analysis was performed using Student’s unpaired t-test to evaluate the significance of normally distributed variables, Mann-Whitney U test and Chi-square test for ordinal data and categorical variables. Results: The groups were comparable with respect to age, weight, gender, and ASA grade. The average mean MAC of sevoflurane at various time intervals was 1.135±0.664635 in group D and 1.9675±0.438 in group C, which was statistically significant. The surgeon’s grading of the surgical field using the Fromme and Boezaart scale was significantly better in group D (1.53±0.45625 versus 2.907±0.5835 in the control group). Although not statistically significant, more number of patients in group C needed additional drugs to lower HR and blood pressure. Conclusion: Dexmedetomidine infusion during FESS is effective in maintaining stable haemodynamics with a lesser need for additional agents to lower HR and Mean Arterial Pressure (MAP). It improves the visibility of the surgical field and decreases the MAC of sevoflurane required to maintain anaesthesia.

Sevoflurane consumption pattern by individual anaesthesiologists varies widely despite using the same high-end workstations in the same hospital.

Volatile anaesthetics are potent greenhouse gasses but contemporary workstations enable considerable savings while improving patient safety. Institutions may provide this technology to reduce the ecological footprint but proper training and motivation is required to maximize their ecologic and financial benefit. This study aims to compare the sevoflurane consumption of 22 anaesthesiologists in a medium sized hospital 4years after flow-i workstations (Getinge, Sweden) entered into service, in three airway approaches: intubated patients, laryngeal mask ventilation, and mask anaesthesia. Typical sevoflurane consumption for each anaesthesiologist was defined as the mean cumulative consumption in the chronologically first 50 cases meeting the inclusion criteria for each airway group in 2019. The potential savings, if everyone were to adopt the approach of the more economical anaesthesiologists (15th percentile), was calculated. The CO2 equivalent emissions were calculated using a GWP20 of 702 and a GWP100 of 195. The median [range] consumption after 45min was 10.9 [7.5-18.4] ml in intubated patients and 9.0 [7.4-15.3] ml in patients with laryngeal mask, and 9.9 [3.4-20.9] ml after 8min with mask ventilation. This corresponds to a double to six fold consumption between the least and most wasteful approach. The typical CO2 equivalent emissions (GWP20) per anaesthesiologist varied between 8.0 and 19.6kg/45min in intubated airways, between 7.9 and 16.3kg/45min in LMA, and between 3.6 and 22.3kg/8min in mask ventilation. Despite using the same workstations in the same hospital, the typical sevoflurane consumption differed dramatically between 22 anaesthesiologists. In addition to providing advanced workstations, proper education is required to achieve the behavior change needed to reduce the pollution and financial waste associated with volatile anaesthetics.

Ventilator-assisted priming of an anaesthesia circuit (VAP technique): An exploratory study.

The speed of inhalational induction depends on a variety of factors, of which priming the breathing circuit with volatile anaesthetics plays a vital role. This study compared ventilator-assisted priming (VAP) and a passive priming technique using different fresh gas flows (FGFs) in neonatal, paediatric, and adult anaesthetic circuits. In both techniques, FGF with 100% oxygen and 8% sevoflurane vaporiser concentration were set at 2 Lmin-1, 4 Lmin-1, and 8 Lmin-1, representing three groups FGF-2, FGF-4, and FGF-8, respectively. The time taken to achieve 6% sevoflurane concentration at the patient end of the circuit was measured. In addition to this, we explored various combinations of tidal volumes and respiratory rates in the VAP technique and recorded the priming time with each combination. The amount of sevoflurane consumed for priming in both techniques was also calculated. VAP was three times faster than passive priming in all the FGF groups in the three circuits. In the VAP technique, the shortest priming times were similar for FGF-4 and FGF-8 (P > 0.05) but were significantly higher for FGF-2 (P = 0.001) in the three circuits. Sevoflurane consumption did not differ in FGF-2 and FGF-4 groups, whereas it doubled in the FGF-8 group using the VAP technique in all three circuits. The VAP technique provides a quick and effective method for priming to achieve a high anaesthetic concentration within the breathing circuit for inhalational induction.

Comparison of Manual Mode With Automatic Gas Control Mode for Sevoflurane Consumption in Maquet Flow-I Anesthesia Machine

Background: Inhalational anesthetic agents used for general anesthesia can have adverse effects on operation theater staff and environment. The innovative automated gas controller reduces inhalational anesthesia agent consumption. Aim: To compare sevoflurane consumption in manual mode versus automatic gas control (AGCTM) mode on Maquet Flow-i anesthesia machine in adult laparoscopic surgeries. Methods: This study was a randomized control trail conducted at Department of anesthesia, Security Forces Hospital Riyadh, Saudi Arabia and Pakistan Kidney and Liver Institute and Research Center, Lahore, Pakistan from December 2019 till December 2020. Sixty patients were randomly divided into two Groups A (Automatic Gas Control, AGCTM) and Group B (Manual Mode). Sevoflurane consumption and sevoflurane consumption rate was calculated in both groups. Data was analyzed using SPSS V.20. Results: Two groups were comparable in term of age, gender, and comorbidities. The mean sevoflurane consumption rate in group A was 23.92+4.6 as compared to 40.23+4.4 in group B (P=0.001). Similarly sevoflurane consumption rate is also statistically significant. (0.28 + 0.04 ml/min vs 0.47 + 0.02 ml/min, p=0.001) Conclusion: Sevoflurane consumption and sevoflurane consumption rate is lower in AGCTM mode as compared to manual mode of Maquet Flow-I anesthesia machine. Keywords: Sevoflurane, Maquet Flow-i, Automatic Gas Controller (AGCTM), Laparoscopic Surgeries

A Comparison of the Cost and Consumption of Sevoflurane and Litholyme at Total Gas Flow Rates of 1 and 2 Liters Per Minute: a Randomized Controlled Trial

Objective: This study aimed to compare the cost-effectiveness of low-flow (1 liter per minute (LPM)) and medium-flow (2 LPM) anesthesia. Material and Methods: Seventy patients aged 18–60 years who were undergoing elective surgery under general anesthesia were randomly allocated to receive a total gas flow rate of 1 LPM (group 1) and 2 LPM (group 2) during the maintenance of anesthesia. The primary outcome was to compare the cost and consumption of sevoflurane and litholyme. The secondary outcomes were hemodynamic stability and time to extubation. Results: The cost and consumption of sevoflurane in group 1 (197.3 Thai Bahts (THB)/hour (hr) and 9.6 milliliter (ml)/ hr) were significantly less than those in group 2 (303.2 THB/hr and 14.8 ml/hr; p-value&lt;0.001). Although there was no difference in the cost and consumption of litholyme between the two groups, the summary cost of sevoflurane and litholyme in group 1 (237.7 THB/hr) was significantly less than that in group 2 (339.6 THB/hr; p-value&lt;0.001). The mean arterial pressure, heart rate, and time to extubation were not significantly different in both groups. Conclusion: Patients undergoing elective surgery under general anesthesia with a total flow of 1 LPM can save on the cost of sevoflurane and litholyme, which is equivalent to 101.9 THB/hr.