The financial and environmental impact of purchased anaesthetic agents in an Australian tertiary hospital.

Anaesthetic agents have various financial and environmental impacts. Climate change is one of the biggest threats to human health, and anaesthetic gases contribute to global heating by acting as greenhouse gases. The primary aim of this study was to quantify the financial and environmental impacts of anaesthesia maintenance agents used during surgery in an Australian university teaching hospital. The volume of desflurane, sevoflurane, isoflurane and propofol purchased by a university teaching hospital between 2010 and 2020 was analysed and described in terms of financial and environmental impact. Estimated carbon emissions and financial costs of each agent per annum were calculated using the volumes purchased for each agent. A model of ideal anaesthetic agent usage was used to hypothesise the financial and environmental impact of replacing desflurane (the most environmentally damaging and expensive agent) with alternative agents. Using 2019 as an example year at our health service, replacing desflurane with low flow sevoflurane would save greenhouse gas emissions equivalent to driving over 1.4 million kilometres in an average petrol car. Removing desflurane from machines at our institution could save an estimated A$14,630 per annum through reduced machine testing alone. Our findings and calculations indicate that reducing the use of desflurane would have both financial and environmental benefits for healthcare.

Malignant hyperthermia in maxillofacial surgery: Literature review supported by case presentation.

OBJECTIVE: Malignant hyperthermia (MH) is characterized by a state of hypermetabolism after exposure to halogenated inhalational anesthetics or succinylcholine. The aims of this study were to carry out an updated review on the subject and report an illustrative case of MH in urgent maxillofacial surgery. MATERIAL AND METHODS: A search of the PubMed/MEDLINE database using the keyword "malignant hyperthermia" was performed including articles published over the last 11 years in English, Spanish or Portuguese. Exclusion criteria were similar presentations but not associated with MH and cases not related to the use of anesthetic drugs as a trigger of the condition. CASE REPORT: A 45-year-old man (75 kg, ASA status IE) with a negative family history for neuromuscular diseases, victim of a car accident with a facial fracture, underwent surgery under balanced general anesthesia and developed signs of MH 4 h after anesthesia induction. In our patient, the causative agent was sevoflurane and the diagnosis of MH was confirmed, subsequently, by muscle biopsy. RESULTS/DISCUSSION: Overall, 44 cases of MH were found. According to the recent literature, MH shows a male predilection (3:1) and the mean age of patients is 32.2 ± 22.2 years. The most frequently cited causative agents were sevoflurane (30.5%), isoflurane (22.2%), and sevoflurane + succinylcholine (13.8%). The most common clinical indicators included hypercarbia (88.8%), hyperthermia (86.1%), and tachycardia (63.8%). Dantrolene was administered in 24 cases. The outcome was favorable in 31 cases (86.1%). The in vitro muscle contracture test (IVCT) was performed in only 15 patients and all of them tested positive. In our patient, the causative agent was sevoflurane and the diagnosis of MH was confirmed by muscle biopsy. CONCLUSION: The mortality from MH is still high and an early clinical diagnosis and specific treatment with dantrolene are necessary for a favorable outcome. A complete understanding will allow better management of patients with MH. At present, the best management is to identify susceptible patients and to avoid triggering agents, combined with vigilant monitoring.

Gene Panel Sequencing Identifies a Novel RYR1 p.Ser2300Pro Variant as Candidate for Malignant Hyperthermia with Multi-Minicore Myopathy.

Malignant hyperthermia (MH), a rare autosomal dominant pharmacogenetic disorder of skeletal muscle calcium regulation, is triggered by sevoflurane in susceptible individuals. We report a Korean having MH with multi-minicore myopathy functionally supported by RYR1-mediated intracellular Ca2+ release testing in B lymphocytes. A 14-year-old boy was admitted for the evaluation of progressive torticollis accompanied by cervicothoracic scoliosis. During the preoperative drape of the patient for the release of the sternocleidomastoid muscle under general anesthesia, his wrist and ankle were observed to have severe flexion contracture. The body temperature was 37.1 °C. To treat MH, the patient was administered a bolus of dantrolene intravenously (1.5 mg/kg) and sodium bicarbonate. After a few minutes, muscle rigidity, tachycardia, and EtCO2 all resolved. Next-generation panel sequencing for hereditary myopathy identified a novel RYR1 heterozygous missense variant (NM_000540.2: c.6898T > C; p.Ser2300Pro), which mapped to the MH2 domain of the protein, a hot spot for MH mutations. Ex vivo RYR1-mediated intracellular Ca2+ release testing in B lymphocytes showed hypersensitive Ca2+ responses to isoflurane and caffeine, resulting in an abnormal Ca2+ release only in the proband, not in his family members. Our findings expand the clinical and pathological spectra of information associated with MH with multi-minicore myopathy.

Invasive and non-invasive assessment of macro- and micro-circulatory effects of vasopressors during sevoflurane anesthesia in a pediatric experimental model: A randomized trial.

BACKGROUND: While non-invasive assessment of macro- and micro-circulation has the promise to optimize anesthesia management, evidence is lacking for the relationship between invasive and non-invasive measurements of cardiac output and microcirculatory indices. AIMS: We aimed to compare the abilities of non-invasive techniques to detect changes in macro- and micro-circulation following deep anesthesia and subsequent restoration of the compromised hemodynamic by routinely used vasopressors in a randomized experimental study. METHODS: A 20%-25% drop in mean arterial pressure was induced by sevoflurane in anesthetized mechanically ventilated just-weaned piglets (n = 12) prior to the administration of vasopressors in random order (dopamine, ephedrine, noradrenaline, and phenylephrine). Simultaneous transpulmonary thermodilution cardiac output assessment with the invasive pulse index continuous contour (PiCCO) method was compared with non-invasive estimates obtained with electrical conductivity (ICON) and echo Doppler (Cardio Q). Changes in microcirculation were characterized by sublingual red blood cell velocity, jugular cerebral venous oxygen saturation, and arterial lactate. MAIN OUTCOME MEASURES: Cardiac output indices obtained by invasive and non-invasive methods. RESULTS: Changes in cardiac output measured invasively and non-invasively correlated significantly after sevoflurane (r = .78, p = .003 and r = .76, p = .006 between PiCCO and ICON or Cardio Q, respectively). Following the administration of vasopressors, invasive and non-invasive cardiac output assessments were unrelated with significant correlations observed only between PiCCO and ICON after dopamine and ephedrine. Sevoflurane-induced hypotension decreased jugular cerebral venous oxygen saturation significantly and was recovered by all vasopressors. Sevoflurane and vasopressors had no effect on red blood cell velocity, which increased only after dopamine. No consistent changes in lactate were observed during the study period. CONCLUSIONS: The results of this study suggest that non-invasive cardiac output measurements may not accurately reflect changes in macrocirculation after hemodynamic optimization by vasopressors. Due to the incoherence between macro- and micro-circulation, monitoring microcirculation is essential to guide patient management.

Minimizing sevoflurane wastage by sensible use of automated gas control technology in the flow-i workstation: an economic and ecological assessment.

Both ecological and economic considerations dictate minimising wastage of volatile anaesthetics. To reconcile apparent opposing stakes between ecological/economical concerns and stability of anaesthetic delivery, new workstations feature automated software that continually optimizes the FGF to reliably obtain the requested gas mixture with minimal volatile anaesthetic waste. The aim of this study is to analyse the kinetics and consumption pattern of different approaches of sevoflurane delivery with the same 2% end-tidal goal in all patients. The consumption patterns of sevoflurane of a Flow-i were retrospectively studied in cases with a target end-tidal sevoflurane concentration (Etsevo) of 2%. For each setting, 25 cases were included in the analysis. In Automatic Gas Control (AGC) regulation with software version V4.04, a speed setting 6 was observed; in AGC software version V4.07, speed settings 2, 4, 6 and 8 were observed, as well as a group where a minimal FGF was manually pursued and a group with a fixed 2 L/min FGF. In 45 min, an average of 14.5 mL was consumed in the 2L-FGF group, 5.0 mL in the minimal-manual group, 7.1 mL in the AGC4.04 group and 6.3 mL in the AGC4.07 group. Faster speed AGC-settings resulted in higher consumption, from 6.0 mL in speed 2 to 7.3 mL in speed 8. The Etsevo target was acquired fastest in the 2L-FGF group and the Etsevo was more stable in the AGC groups and the 2L-FGF groups. In all AGC groups, the consumption in the first 8 min was significantly higher than in the minimal flow group, but then decreased to a comparable rate. The more recent AGC4.07 algorithm was more efficient than the older AGC4.04 algorithm. This study indicates that the AGC technology permits very significant economic and ecological benefits, combined with excellent stability and convenience, over conventional FGF settings and should be favoured. While manually regulated minimal flow is still slightly more economical compared to the automated algorithm, this comes with a cost of lower precision of the Etsevo. Further optimization of the AGC algorithms, particularly in the early wash-in period seems feasible. In AGC mode, lower speed settings result in significantly lower consumption of sevoflurane. Routine clinical practice using what historically is called "low flow anaesthesia" (e.g. 2 L/min FGF) should be abandoned, and all anaesthesia machines should be upgraded as soon as possible with automatic delivery technology to minimize atmospheric pollution with volatile anaesthetics.

In vitro assessment of the direct hemolytic effect of the volatile halogenated anesthetics sevoflurane, isoflurane, and desflurane.

Sevoflurane is being repurposed as a topical analgesic for painful wounds. Providing pre-charged sevoflurane syringes to irrigate wounds implies a potential risk of accidental intravenous injections. We assessed the potential of two concentrations (33% and 50% v/v) of three anesthetics, isoflurane, desflurane and sevoflurane, to produce hemolysis in vitro. Spectrophotometric absorbance was read at 576 nm. For both concentrations, the percentage of hemolysis (mean ± SD) was higher for isoflurane (29.7 ± 3.4% and 39.5 ± 5.3%), mild for desflurane (8.0 ± 0.5% and 6.5 ± 0.9%) and negligible for sevoflurane (0.7 ± 0.0% and 0.6 ± 0.1%), respectively. In conclusion, in contrast to isoflurane and desflurane, sevoflurane did not display hemolytic potential in vitro. However, the use of syringes preloaded with sevoflurane may still be problematic if it increases the possibility of inadvertent intravenous administration through increased risk of gas embolism and severe central nervous system depression.

Cost-effectiveness analysis of domiciliary topical sevoflurane for painful leg ulcers.

OBJECTIVES: The general anesthetic sevoflurane is being repurposed as a topical analgesic for painful chronic wounds. We conducted a Bayesian cost-effectiveness analysis (CEA) comparing the addition of domiciliary topical sevoflurane to conventional analgesics (SEVOFLURANE, n = 38) versus conventional analgesics alone (CONVENTIONAL, n = 26) for the treatment of nonrevascularizable painful leg ulcers in an outpatient Pain Clinic of a Spanish tertiary hospital. METHODS: We used real-world data collected from charts to conduct this CEA from a public healthcare perspective and with a one-year time horizon. Costs of analgesics, visits and admissions were considered, expressed in €2016. Analgesic effectiveness was measured with SPID (Sum of Pain Intensity Difference). A Bayesian regression model was constructed, including "treatment" and baseline characteristics for patients ("arterial hypertension") and ulcers ("duration", "number", "depth", "pain") as covariates. The findings were summarized as a cost-effectiveness plane and a cost-effectiveness acceptability curve. One-way sensitivity analyses, a re-analysis excluding those patients who died or suffered from leg amputation, and an extreme scenario analysis were conducted to reduce uncertainty. RESULTS: Compared to CONVENTIONAL, SEVOFLURANE was associated with a 46% reduction in costs, and the mean incremental effectiveness (28.15±3.70 effectiveness units) was favorable to SEVOFLURANE. The estimated probability for SEVOFLURANE being dominant was 99%. The regression model showed that costs were barely influenced by any covariate, whereas effectiveness was noticeably influenced by "treatment". All sensitivity analyses showed the robustness of the model, even in the extreme scenario analysis against SEVOFLURANE. CONCLUSIONS: SEVOFLURANE was dominant over CONVENTIONAL as it was less expensive and much more effective.

DNA damage assessment in peripheral blood of Swiss albino mice after combined exposure to volatile anesthetics and 1 or 2 Gy radiotherapy in vivo.

PURPOSE: Patient immobilization by general volatile anesthesia (VA) may be necessary during medical radiology treatment, and its use has increased in recent years. Although ionizing radiation (IR) is a well-known genotoxic and cytotoxic agent, and VA exposure has caused a range of side effects among patients and occupationally exposed personnel, there are no studies to date comparing DNA damage effects from combined VA and single fractional IR dose exposure. MATERIAL AND METHODS: We investigate whether there is a difference in white blood cells DNA damage response (by the alkaline comet assay) in vivo in 185 healthy Swiss albino mice divided into 37 groups, anesthetized with isoflurane/sevoflurane/halothane and exposed to 1 or 2 Gy of IR. Blood samples were taken after 0, 2, 6 and 24 h after exposure, and comet parameters were measured: tail length, tail intensity and tail moment. The cellular DNA repair index was calculated to quantify the efficiency of cells in repairing and re-joining DNA strand breaks following different treatments. RESULTS: In combined exposures, halothane caused higher DNA damage levels that were dose-dependent; sevoflurane damage increase did not differ significantly from the initial 1 Gy dose, and isoflurane even demonstrated a protective effect, particularly in the 2 Gy dose combined exposure. Nevertheless, none of the exposures reached control levels even after 24 h. CONCLUSION: Halothane appears to increase the level of radiation-induced DNA damage, while sevoflurane and isoflurane exhibited a protective effect. DNA damage may have been even greater in target organs such as liver, kidney or even the brain, and this is proposed for future study.

Evidence-Based Project: Cost Savings and Reduction in Environmental Release With Low-Flow Anesthesia.

Volatile anesthetic agents act as greenhouse gases. Low-flow anesthesia techniques (≤1 L/min) are associated with lower costs. Decreasing volatile anesthetic delivery provides safe and effective strategies for anesthesia providers to decrease costs and reduce environmental pollution. This evidence-based project aimed to estimate cost savings and reduction in the environmental release of anesthetic gases, under simulated lower fresh gas flow (FGF) practices. For each surgical case, the exhaled anesthetic gas percent and FGF data were used to calculate the volume of fluid volatile anesthetic. The fluid volatile anesthetic for each case was then estimated using simulated FGFs. Changes in volatile agent cost and environmental release of anesthetic gases were predicted. Sevoflurane was the most commonly used volatile agent. The mean FGF for cases using sevoflurane was 2.5 L/min. The simulated FGF of 1 L/min FGF across all agents predicted a 48% ($50,892) reduction in costs of volatile anesthetics and a 42% (33 metric tons of carbon dioxide equivalent) decrease in carbon emissions. Simulated low-flow anesthesia demonstrated cost savings and environmental conservation. Project findings align with current literature showing that lowering FGFs represents an area of cost containment and an opportunity to lessen the environmental impact of anesthesia.

The Drug Titration Paradox: Correlation of More Drug With Less Effect in Clinical Data.

While analyzing clinical data where an anesthetic was titrated based on an objective measure of drug effect, we observed paradoxically that greater effect was associated with lesser dose. With this study we sought to find a mathematical explanation for this negative correlation between dose and effect, to confirm its existence with additional clinical data, and to explore it further with Monte Carlo simulations. Automatically recorded dosing and effect data from more than 9,000 patients was available for the analysis. The anesthetics propofol and sevoflurane and the catecholamine norepinephrine were titrated to defined effect targets, i.e., the processed electroencephalogram (Bispectral Index, BIS) and the blood pressure. A proportional control titration algorithm was developed for the simulations. We prove by deduction that the average dose-effect relationship during titration to the targeted effect will associate lower doses with greater effects. The finding of negative correlations between propofol and BIS, sevoflurane and BIS, and norepinephrine and mean arterial pressure confirmed the titration paradox. Monte Carlo simulations revealed two additional factors that contribute to the paradox. During stepwise titration toward a target effect, the slope of the dose-effect data for the population will be "reversed," i.e., the correlation between dose and effect will not be positive, but will be negative, and will be "horizontal" when the titration is "perfect." The titration paradox must be considered whenever data from clinical titration (flexible dose) studies are interpreted. Such data should not be used naively for the development of dosing guidelines.

Probabilistic health risk assessment of occupational exposure to isoflurane and sevoflurane in the operating room.

Risk assessment is an important tool in predicting the possible risk to health. It heightens awareness by estimating the probability of adverse health effects in humans who are exposed to chemicals in the course of their work. Therefore, the present work aims to determine the occupational exposure of operating room staff to the volatile anesthetic gases, isoflurane and sevoflurane, and estimates non-cancer risk using the United States Environmental Protection Agency method. Air samples from the breathing zone of staff members were collected using the Occupational Safety and Health Administration Method 103 and analyzed using gas chromatography-mass spectroscopy. The results indicate that the measured concentrations of isoflurane and sevoflurane are below the National Institute of Occupational Safety and Health standard (2 ppm) for technicians and nurses, but not for anesthesiologists and surgeons. Moreover, the estimated non-cancer risk due to isoflurane is above the acceptable value for anesthesiologists (but acceptable for other occupational categories). A sensitivity analysis indicates that exposure time has the most effect on calculated risk (53.4%). Occupational exposure to anesthetic gases may endanger the health of operating room personnel. Therefore, control measures, such as daily testing of anesthetic devices, ensuring the effectiveness of ventilation systems, advanced scavenging methods, and regular training of staff are highly recommended.

A multimodal sevoflurane-based sedation regimen in combination with targeted temperature management in post-cardiac arrest patients reduces the incidence of delirium: An observational propensity score-matched study.

BACKGROUND: Recent studies suggest that volatile anaesthetics are safe, efficient, and reliable alternatives to the use of intravenous anaesthetics for out-of-hospital cardiac arrest (OHCA) patients admitted to the intensive care unit (ICU). We hypothesised that volatile anaesthetics may reduce the incidence of delirium rather than intravenous sedatives. This retrospective study aimed to investigate whether sevoflurane combined with higher targeted temperature management could decrease the incidence of delirium when compared with intravenous anaesthetics with lower targeted temperature management. METHODS: Using a propensity score-matched analysis, we retrospectively compared a target temperature management (32-34 °C) method along with intravenous sedation (TTM-33/IV) and a modified target temperature management (34-36 °C) method along with sevoflurane sedation (mTTM-36/sevo). We used the confusion assessment method for the ICU to measure the incidence of delirium. We calculated the time-dependent risk on delirium using the multivariate Cox regression model. RESULTS: The incidence of delirium was significantly lower (p = 0.001) in OHCA patients of the mTTM-36/sevo group (9/56, 16.1%) than in those of the TTM-33/IV group (25/67, 37.3%). Mechanical ventilation and lengths of stay in the ICU (p < 0.001) and hospital stay (p = 0.04) were shorter in the mTTM-36/sevo group. Patients in the TTM-33/IV group required more midazolam, propofol, and fentanyl. We observed no significant difference in mortality. CONCLUSION: A multimodal sevoflurane-based sedation regimen together with targeted temperature management resulted in a lower incidence of delirium and a shorter duration for mechanical ventilation and ICU length of stay than did the treatment with intravenous sedation combined with the classical cooling protocol.

The impact of sevoflurane anesthesia on postoperative renal function: a systematic review and meta-analysis of randomized-controlled trials.

PURPOSE: Renal damage secondary to fluoride ions and compound A (CpdA) after sevoflurane anesthesia remains unclear. For safety reasons, some countries still recommend minimum fresh-gas flows (FGFs) with sevoflurane. We review the evidence regarding the intraoperative use of sevoflurane for anesthesia maintenance and postoperative renal function compared with other anesthetic agents used for anesthetic maintenance. Secondarily, we examine the effects of peak plasma fluoride and CpdA levels and the effect of FGF and duration of anesthesia on these parameters. SOURCE: The databases of MEDLINE (OVID and Pubmed), EMBASE, the Cochrane Library, Health Technology Assessment Database, CINAHL, and Web of Science were searched from inception until 23 April 2020 to identify randomized-controlled trials (RCTs) in humans utilizing sevoflurane or an alternative anesthetic for anesthesia maintenance with subsequent measurements of renal function. Two different paired reviewers independently selected the studies and extracted data. The quality of the evidence was appraised using GRADE recommendations. PRINCIPAL FINDINGS: Of 3,766 publications screened, 41 RCTs in human patients were identified. There was no difference between creatinine at 24 hr (21 studies; n = 1,529), or creatinine clearance (CCR) at 24 hr (12 studies; n = 728) in the sevoflurane vs alternative anesthetic groups. Peak fluoride and fluoride measured at 24 hr were higher with sevoflurane compared with other inhaled anesthetics. Subgroup analyses for sevoflurane usage in various contexts showed no significant difference between sevoflurane and alternative anesthetics for creatinine or CCR at 24 hr at varying FGF, duration of exposure, baseline renal function, or absorbent use. CONCLUSIONS: We did not find any association between the use of sevoflurane and postoperative renal impairment compared with other agents used for anesthesia maintenance. The scientific basis for recommending higher FGF with the use of sevoflurane needs to be revisited.

RéSUMé: OBJECTIF: Les lésions rénales secondaires aux ions fluorure et au composé A (CpdA) après une anesthésie au sévoflurane demeurent incertaines. Pour des raisons de sécurité, certains pays recommandent encore des débits de gaz frais (DGF) minimaux lors de l'utilisation du sévoflurane. Nous avons passé en revue les données probantes concernant l'utilisation peropératoire de sévoflurane pour le maintien de l'anesthésie sur la fonction rénale postopératoire comparativement à d'autres agents anesthésiques utilisés pour le maintien de l'anesthésie. En analyse secondaire, nous avons examiné les effets des taux plasmatiques maximaux de fluorure et de CpdA et l'effet du DGF et de la durée de l'anesthésie sur ces paramètres. SOURCE: Des recherches ont été menées dans les bases de données de MEDLINE (OVID et Pubmed), EMBASE, the Cochrane Library, Health Technology Assessment Database, CINAHL et Web of Science, de leur création jusqu'au 23 avril 2020. Nous y avons identifié les études randomisées contrôlées (ERC) réalisées sur des sujets humains utilisant du sévoflurane ou un agent anesthésique alternatif pour le maintien de l'anesthésie et présentant des mesures subséquentes de la fonction rénale. Deux différents réviseurs appariés ont sélectionné de manière indépendante les études et extrait les données. La qualité des données probantes a été évaluée à l'aide des recommandations GRADE. CONSTATATIONS PRINCIPALES: Parmi les 3766 publications passées en revue, 41 ERC réalisées chez des patients humains ont été identifiées. Aucune différence n'a été observée en ce qui touchait à la valeur de créatinine à 24 h (21 études; n = 1529) ou de la clairance de la créatinine (CCR) à 24 h (12 études; n = 728) dans les groupes sévoflurane vs autres anesthésiques. Les taux maximaux de fluorure et le fluorure mesuré à 24 h étaient plus élevés lors de l'utilisation de sévoflurane que d'autres agents anesthésiques halogénés. Les analyses de sous-groupe portant sur l'utilisation du sévoflurane dans divers contextes n'ont démontré aucune différence significative entre le sévoflurane et les autres anesthésiques en matière de valeur de créatinine ou de CCR à 24 h selon différents DGF, durées d'exposition, fonctions rénales de base ou absorbants. CONCLUSION: Nous n'avons pas trouvé d'association entre l'utilisation du sévoflurane et des détériorations de la fonction rénale postopératoires par rapport aux autres agents utilisés pour le maintien de l'anesthésie. Les raisons scientifiques sur lesquelles repose la recommandation d'un DGF plus élevé lors de l'utilisation de sévoflurane doivent être réexaminées.

Sevoflurane Consumption During Inhalational Induction in Children: A Randomized Comparison of Minute Ventilation-Based Techniques With Standard Fixed Fresh Gas Flow Technique.

This study was done to ascertain the optimum fresh gas flow (FGF) offering the best balance between rapid induction and minimal waste in pediatric patients. Forty-five children (weighing 10-20 kg) undergoing elective procedures under general anesthesia were randomly assigned into 3 groups: 0.5 minute ventilation (MV), MV, and S (FGF = 6 L/min). After priming the pediatric closed circuit, anesthesia was induced using a face mask with 8% sevoflurane in 100% oxygen (Draeger Primus Vista 120 anesthesia machine) at FGF-determined MV per group allocation. After loss of eyelash reflex (time 1 [T1]), intravenous cannulation (T2) and laryngeal mask airway (LMA) placement (T3) were done. Total sevoflurane consumed during induction (measured using logbook function) was the primary outcome. The cost of sevoflurane, any reflex movement, tachycardia (heart rate change > 20%), or additional propofol boluses required were also recorded. Sevoflurane consumption (3.8 vs 5.8 vs 9.2 mL) and cost of sevoflurane (104.2 vs 199.4 vs 312.8 rupees) were lowest in group 0.5 MV (P < .001). There was no difference in hemodynamic parameters, movement on cannulation/LMA insertion, and rescue propofol boluses required. For pediatric sevoflurane induction, half the MV-based FGF provided similar anesthetic conditions for LMA insertion with minimum sevoflurane consumption.

The Effect of Erector Spinae Plane Block on Laparoscopic Cholecystectomy Anesthesia: Analysis of Opioid Consumption, Sevoflurane Consumption, and Cost.

Background: Erector spinae plane (ESP) block has been increasingly suggested for laparoscopic cholecystectomy (LC) as a part of multimodal analgesia in many studies. However, there is not any study that investigated the perioperative effects of ESP block on anesthetic agent consumption and cost of LC anesthesia. This is the first study that evaluates the effect of ESP block in terms of cost-effectiveness, intraoperative consumption of inhalation agents, and perioperative consumption of opioids. Materials and Methods: In this prospective observational study, 81 patients who underwent LC were included. Patients were divided into two groups: In Group ESP (n = 39) bilateral ultrasound-guided ESP block was performed in preoperative period and in Group non-ESP (n = 42) ESP block was not performed. After standard general anesthesia protocol, anesthesia was maintained with 2% sevoflurane in 50% air and 50% oxygen with controlled ventilation in both groups. All patients were monitored with electrocardiography, noninvasive blood pressure, pulse oximetry, end-tidal carbon dioxide, and bispectral index. The consumption of sevoflurane and opioids in the intraoperative and postoperative 24 hours was recorded. The costs of drugs were determined by multiplying total consumed amounts with unit prices. Results: The costs and the consumed amounts of remifentanyl, sevoflurane, and tramadol were significantly higher in non-ESP group in the perioperative period (respectively, P < .001, P = .01, and P < .001). Conclusions: ESP block for LC decreased the consumed amount and cost of inhaled agents and opioids in the perioperative period.

Estimating the Impact of Carbon Dioxide Absorbent Performance Differences on Absorbent Cost During Low-Flow Anesthesia.

BACKGROUND: Reducing fresh gas flow when using a circle anesthesia circuit is the most effective strategy for reducing both inhaled anesthetic vapor cost and waste. As fresh gas flow is reduced, the amount of exhaled gas rebreathed increases, but the utilization of carbon dioxide absorbent increases as well. Reducing fresh gas flow may not make economic sense if the increased cost of absorbent utilization exceeds the reduced cost of anesthetic vapor. The primary objective of this study was to determine the minimum fresh gas flow at which absorbent costs do not exceed vapor savings. Another objective is to provide a qualitative insight into the factors that influence absorbent performance as fresh gas flow is reduced. METHODS: A mathematical model was developed to compare the vapor savings with the cost of carbon dioxide absorbent as a function of fresh gas flow. Parameters of the model include patient size, unit cost of vapor and carbon dioxide absorbent, and absorbent capacity and efficiency. Boundaries for fresh gas flow were based on oxygen consumption or a closed-circuit condition at the low end and minute ventilation to approximate an open-circuit condition at the high end. Carbon dioxide production was estimated from oxygen consumption assuming a respiratory quotient of 0.8. RESULTS: For desflurane, the cost of carbon dioxide absorbent did not exceed vapor savings until fresh gas flow was almost equal to closed-circuit conditions. For sevoflurane, as fresh gas flow is reduced, absorbent costs increase more slowly than vapor costs decrease so that total costs are still minimized for a closed circuit. Due to the low cost of isoflurane, even with the most effective absorbent, the rate of absorbent costs increase more rapidly than vapor savings as fresh gas flow is reduced, so that an open circuit is least expensive. The total cost of vapor and absorbent is still lowest for isoflurane when compared with the other agents. CONCLUSIONS: The relative costs of anesthetic vapor and carbon dioxide absorbent as fresh gas flow is reduced are dependent on choice of anesthetic vapor and performance of the carbon dioxide absorbent. Absorbent performance is determined by the product selected and strategy for replacement. Clinicians can maximize the performance of absorbents by replacing them based on the appearance of inspired carbon dioxide rather than the indicator. Even though absorbent costs exceed vapor savings as fresh gas flow is reduced, isoflurane is still the lowest cost choice for the environmentally sound practice of closed-circuit anesthesia.

Provider Education and Vaporizer Labeling Lead to Reduced Anesthetic Agent Purchasing With Cost Savings and Reduced Greenhouse Gas Emissions.

Anesthetic agents are known greenhouse gases with hundreds to thousands of times the global warming impact compared with carbon dioxide. We sought to mitigate the negative environmental and financial impacts of our practice in the perioperative setting through multidisciplinary staff engagement and provider education on flow rate reduction and volatile agent choice. These efforts led to a 64% per case reduction in carbon dioxide equivalent emissions (163 kg in Fiscal Year 2012, compared with 58 kg in Fiscal Year 2015), as well as a cost savings estimate of $25,000 per month.

Perioperative interdisciplinary approach for reduction of opioid use in pediatric tonsillectomy: Protocol using dexmedetomidine and bupivicaine as adjunct agents.

IMPORTANCE: Pediatric tonsillectomy is a common procedure now being performed most often for patients with obstructive sleep apnea, which has been associated with increased sensitivity to the respiratory side effects of opioid medications. This study investigates a strategy to decrease the use of opiate medications in a particularly vulnerable population. OBJECTIVE: Describe an interdisciplinary approach between Otolaryngologists and Anesthesiologists to decrease opiate use in tonsillectomy patients. Demonstrate safety of this protocol. Evaluate the effect of the protocol on intraoperative need for opiate medications and inhaled anesthetic use. Perform cost analysis of the protocol. DESIGN: Retrospective case-control study with cost analysis. SETTING: Tertiary Care Hospital. PARTICIPANTS: Pediatric patients undergoing tonsillectomy at a tertiary care hospital. INTERVENTIONS: Preoperative and intraoperative dexmedetomidine with local bupivacaine injection into the tonsillar fossa. MEASURES: Intraoperative need for sevoflurane, opiate, and propofol. Post-operative pain scores, and utilization of post-operative opiate, acetaminophen, and ibuprofen pain medications. Post-operative adverse events. Cost analysis of protocol. RESULTS: This protocol led to a decrease in intraoperative opiate use by 49.6%, a decrease in intraoperative sevofluorane use by 18%, and a lower reported maximum post-operative pain score without any increase in adverse events. The protocol added a small increase in medication cost of $4.07 to each procedure. CONCLUSION: The use of dexmedetomidine and local anesthetic in pediatric tonsillectomy is a safe and effective protocol that allows for the reduction of opiate use and improved post-operative pain control. KEY POINTS: Question: Can the combination of dexmedetomidine and infiltration of local anesthetic reduce overall opioid use for peediatric patients undergoing tonsillectomy? FINDINGS: In this case-control study, use of dexmedetomidine and local anesthetic injected into the tonsillar fossa led to a decrease in intraoperative opiate use by 49.6%, a decrease in intraoperative sevofluorane use by 18%, and a lower reported maximum pain score without an increase in adverse events. Meaning: Use of dexmedetomidine and local anesthetic as anesthetic adjuncts may help reduce need for intraoperative opiates and decrease the use of volatile anesthetic agents in pediatric tonsillectomy patients, which are undesirable medications in the pediatric population for their respective respiratory depression and potentially neurotoxic side effects.

On-table extubation in neonates undergoing anoplasty: an experience of anesthetic management on the concept of fast-tracking anesthesia: A pilot study.

Fast-track anesthesia (FTA) is difficult to achieve in neonates due to immature organ function and high rates of perioperative events. As a high-risk population, neonates require prolonged postoperative mechanical ventilation, which may lead to contradictions in cases where neonatal intensive care unit resources and ventilator facilities are limited. The choice of anesthesia strategy and anesthetic can help achieve rapid postoperative rehabilitation and save hospitalization costs. The authors describe their experience with maintaining spontaneous breathing in neonates undergoing anoplasty without opioids or muscle relaxants.This retrospective chart review included neonates who underwent anoplasty in the authors' institution. Twelve neonates who underwent the procedure with atomized 5% lidocaine topical anesthesia around the glottis, combined with sevoflurane sedation and caudal anesthesia facilitating tracheal intubation without opioid and muscle relaxant comprised the FTA group. Ten neonates who underwent the intervention with routine anesthesia techniques in the same period comprised the control group (group C).The surgical success rate in the FTA group was 91.7%. There were no severe complications related to lidocaine administered around the glottis. Extubation time was significantly shorter in the FTA group than in group C (4 [2.5, 5.2] vs 81.5 [60.6, 96.8], respectively; P < .01). The duration of stay in the surgical intensive care unit (SICU) was longer in group C than in the FTA group (2 [2.0, 2.6] vs 1 [0.9, 2.0], respectively; P = .006,). A statistically significant lower rate of extubation-cough was noted after endotracheal tube removal in the FTA group compared with group C (18% vs 90%, respectively; P < .001). There was no difference in the duration of anesthesia or hospitalization costs between the 2 groups. No neonates required re-intubation after extubation.On-table extubation via 5% atomized lidocaine topical anesthesia around the glottis for tracheal intubation combined with sevoflurane sedation and caudal anesthesia without opioid and muscle relaxant was feasible in neonates undergoing anoplasty. This reduced time to extubation, length of SICU stay and saved resources. A similar trend in cost savings was also found; nevertheless, more studies are needed to confirm these results.

Comparison of low-fresh gas flow technique to standard technique of sevoflurane induction in children-A randomized controlled trial.

BACKGROUND: Although sevoflurane is preferred for inhalational induction in children, financial and environmental costs remain major limitations. The aim of this study was to determine if the use of low-fresh gas flow during inhalational induction with sevoflurane could significantly reduce agent consumption, without adversely affecting induction conditions. METHODS: After institutional ethical committee approval, 50 children, aged 1-5 years, undergoing ophthalmic procedures under general anesthesia, were randomized into two groups-standard induction (Group S) and low-flow induction (Group L). A pediatric circle system with 1 L reservoir bag was primed with 8% sevoflurane in oxygen at 6 L min-1 for 30 seconds before beginning induction. In Group S, fresh gas flow was maintained at 6 L min-1 until the end of induction. In Group L, fresh gas flow was reduced to 1 L min-1 after applying facemask (time = T0). In both groups, sevoflurane was reduced to 5% after loss of eyelash reflex (T1). Once adequate depth of anesthesia was achieved (regular respiration, loss of muscle tone, and absence of movement to trapezius squeeze), intravenous access was secured (T2), followed by insertion of an appropriately sized LMA-Classic™ (T3). Heart rate and endtidal sevoflurane concentration were measured at each of the above time points, and at 15 seconds following laryngeal mask airway insertion (T4). The total amount of sevoflurane consumed during induction was recorded. RESULTS: Sevoflurane consumption was significantly lower in Group L (4.17 ± 0.70 mL) compared to Group S (8.96 ± 1.11 mL) (mean difference 4.79 [95% CI = 4.25-5.33] mL; P < 0.001). Time to successful laryngeal mask airway insertion was similar in both groups. There were no significant differences in heart rate, incidence of reflex tachycardia, or need for rescue propofol. CONCLUSION: Induction of anesthesia with sevoflurane using low-fresh gas flow is effective in reducing sevoflurane consumption, without compromising induction time and conditions.