Dementia risk amongst older adults with hip fracture receiving general anaesthesia or regional anaesthesia: a propensity-score-matched population-based cohort study.

BACKGROUND: Preclinical studies have indicated that anaesthesia is an independent risk factor for dementia, but the clinical associations between dementia and different types of general anaesthesia or regional anaesthesia remain unclear. We conducted a population-based cohort study using propensity-score matching to compare dementia incidence in patients included in the Taiwanese National Health Insurance Research Database who received various anaesthetic types for hip fracture surgery. METHODS: Patients aged ≥65 yr who received elective hip fracture surgery from 2002 to 2019 were divided into three groups receiving either inhalational anaesthesia (GA), total intravenous anaesthesia-general anaesthesia (TIVA-GA), or regional anaesthesia (RA), and matched in a 1:1 ratio. The incidence rates of dementia were then determined. RESULTS: Propensity-score matching yielded 89 338 patients in each group (N=268 014). Dementia incidence rates in the inhalational GA, TIVA-GA, and RA groups were 4821, 3400, and 2692 per 100 000 person-years, respectively. The dementia incidence rate ratio (95% confidence interval [CI]) for inhalational GA to TIVA-GA was 1.19 (1.14-1.25), for inhalational GA to RA was 1.51 (1.15-1.66), and for TIVA-GA to RA was 1.28 (1.09-1.51). CONCLUSIONS: The incidence rate ratios of dementia amongst older adults undergoing hip fracture surgery were higher for those receiving general anaesthesia than for those receiving regional anaesthesia, with inhalational anaesthesia associated with a higher incidence rate ratio for dementia than total intravenous anaesthesia (TIVA).

On the horns of a dilemma: choosing total intravenous anaesthesia or volatile anaesthesia.

There are two established techniques of delivering general anaesthesia: propofol-based total intravenous anaesthesia (TIVA) and volatile agent-based inhaled anaesthesia. Both techniques are offered as standard of care and have an established safety track record lasting more than 30 years. However, it is not currently known whether the choice of anaesthetic technique results in a fundamentally different patient experience or affects early, intermediate-term, and longer-term postoperative outcomes. This editorial comments on a recently published study that suggests that inhaled volatile anaesthesia might be associated with fewer postoperative surgical complications than propofol-based TIVA for patients undergoing colorectal cancer surgery. We consider the strengths and limitations of the study, place these findings in the context of the broader evidence, and discuss how the current controversies regarding anaesthetic technique can be resolved, thereby helping to bring precision medicine into the modern practice of perioperative care.

Inhalation or total intravenous anaesthesia and recurrence after colorectal cancer surgery: a propensity score matched Danish registry-based study.

BACKGROUND: During colorectal cancer surgery, the immune-modulating effects of inhalation anaesthesia may create a favourable environment for metastasis formation, leading to increased risk of recurrence. Our aim was to assess the association between inhalation vs intravenous anaesthesia and cancer recurrence in patients undergoing colorectal cancer surgery. METHODS: Patients undergoing colorectal cancer surgery in 2004-18 were identified in the Danish Colorectal Cancer Group Database and Danish Anaesthesia Database. After exclusion of patients with residual tumour registered in postoperative pathology reports, local endoscopic resections, and stent insertions, we classified patients according to exposure to inhalation anaesthesia. The primary outcome was recurrence (time to recurrence), whereas secondary outcomes were all-cause mortality (time to death) and disease-free survival (time to either recurrence or death). Events of recurrence and death were identified using The Danish Civil Registration System, Danish National Pathology Registry, and Danish National Patient Registry. The sub-distribution hazards approach was used to estimate hazard ratios (HRs) for recurrence, and Cox regression was used for all-cause mortality and disease-free survival. RESULTS: We identified 5238 patients exposed to inhalation anaesthesia and 6322 to intravenous anaesthesia. Propensity score matching yielded 4347 individuals in each group with balanced baseline covariates. We found a weak association between recurrence and exposure to inhalation anaesthesia (HR=1.12; 95% confidence interval [CI], 1.02-1.23). The HR estimates for all-cause mortality and disease-free survival were 1.00 (95% CI, 0.93-1.07) and 1.04 (95% CI, 0.98-1.11) respectively. CONCLUSION: Exposure to inhalation anaesthesia was associated with increased risk of recurrence after colorectal cancer surgery.

Evaluation of a novel waste anaesthetic gas scavenger device for use during recovery from anaesthesia.

Volatile anaesthetic agents are a potential occupational health hazard to theatre and recovery staff. Operating theatres and anaesthetic rooms are required to be equipped with scavenging systems, but recovery units often are not. We compared exhaled, spectrophotometric sevoflurane and desflurane concentrations 15 cm from the mouth ('patient breathing zone') and 91 cm laterally to the patient ('nurse work zone') in 120 patients after tracheal extubation who were consecutively allocated to either ISO-Gard mask oxygen/scavenging or standard oxygen mask, 0 min, 10 min and 20 min after arrival in the theatre recovery unit. Median (IQR [range]) duration of anaesthesia was similar between groups (control 76 (44-119 [15-484]) min vs. study group 90 (64-130 [15-390]) min, p = 0.136). Using the ISO-Gard mask, the 20-min mean patient breathing zone and nurse work zone exhaled anaesthetic levels were ~ 90% and 78% lower than those recorded in the control group, respectively, and were within the recommended 2 ppm maximum environmental exposure limit in the patient breathing zone of 53 out of 60 (88%) and the nurse work zone of all 60 (100%) patients on first measurement in the recovery room (vs. 10 out of 60 (17%) and 40 out of 60 (67%) in the control group). Our study indicates that the ISO-Gard oxygen/scavenging mask reduces the level of exhaled sevoflurane and desflurane below recommended maximum exposure limits near > 85% of extubated patients within ~ 20 s of application in the recovery unit after surgery. We encourage the use of this mask to minimise the occupational exposure of recovery staff to exhaled volatile agents.

Propofol vs. inhalational agents to maintain general anaesthesia in ambulatory and in-patient surgery: a systematic review and meta-analysis.

BACKGROUND: It is unclear if anaesthesia maintenance with propofol is advantageous or beneficial over inhalational agents. This study is intended to compare the effects of propofol vs. inhalational agents in maintaining general anaesthesia on patient-relevant outcomes and patient satisfaction. METHODS: Studies were identified by electronic database searches in PubMed™, EMBASE™ and the Cochrane™ library between 01/01/1985 and 01/08/2016. Randomized controlled trials (RCTs) of peer-reviewed journals were studied. Of 6688 studies identified, 229 RCTs were included with a total of 20,991 patients. Quality control, assessment of risk of bias, meta-bias, meta-regression and certainty in evidence were performed according to Cochrane. Common estimates were derived from fixed or random-effects models depending on the presence of heterogeneity. Post-operative nausea and vomiting (PONV) was the primary outcome. Post-operative pain, emergence agitation, time to recovery, hospital length of stay, post-anaesthetic shivering and haemodynamic instability were considered key secondary outcomes. RESULTS: The risk for PONV was lower with propofol than with inhalational agents (relative risk (RR) 0.61 [0.53, 0.69], p < 0.00001). Additionally, pain score after extubation and time in the post-operative anaesthesia care unit (PACU) were reduced with propofol (mean difference (MD) - 0.51 [- 0.81, - 0.20], p = 0.001; MD - 2.91 min [- 5.47, - 0.35], p = 0.03). In turn, time to respiratory recovery and tracheal extubation were longer with propofol than with inhalational agents (MD 0.82 min [0.20, 1.45], p = 0.01; MD 0.70 min [0.03, 1.38], p = 0.04, respectively). Notably, patient satisfaction, as reported by the number of satisfied patients and scores, was higher with propofol (RR 1.06 [1.01, 1.10], p = 0.02; MD 0.13 [0.00, 0.26], p = 0.05). Secondary analyses supported the primary results. CONCLUSIONS: Based on the present meta-analysis there are several advantages of anaesthesia maintenance with propofol over inhalational agents. While these benefits result in an increased patient satisfaction, the clinical and economic relevance of these findings still need to be addressed in adequately powered prospective clinical trials.

Volatile anaesthesia during cardiopulmonary bypass.

Since its inception, administering and ensuring anaesthesia during cardiopulmonary bypass has been challenging. Partly because of the difficulty of administering volatile agents during cardiopulmonary bypass, total intravenous anaesthesia has been a popular technique used by cardiac anaesthetists in the last two decades. However, the possibility that volatile agents reduce mortality and the incidence of myocardial infarction by preconditioning the myocardium has stimulated a resurgence of interest in their use for cardiac anaesthesia. The aim of this review is to provide an overview of the administration of volatile anaesthetic agents during cardiopulmonary bypass for the maintenance of anaesthesia and to address some of the practical issues that are involved in doing so.

Comparison of Complications between Total Intravenous Anaesthesia and Combined Intravenous and Inhalation Anaesthesia after Renal Biopsy in Children.

OBJECTIVE: The objective of this study was to examine the influence of total intravenous anaesthesia (TIVA) compared to combined intravenous and inhalation anaesthesia (CIIA) in paediatric patients undergoing renal biopsy. METHODS: A total of 86 children with nephrotic syndrome, acute glomerulonephritis, chronic glomerulonephritis, IgG nephropathy, systemic lupus erythematosus and purpura nephritis were selected from January 2018 to January 2023 in our hospital. All children were divided into the total intravenous anaesthesia group and intravenous inhalational anaesthesia group according to the anaesthesia method. The experimental group comprised 46 children with renal diseases who underwent static aspiration compound anaesthesia during renal biopsy at our hospital from January 2018 to January 2023. Conversely, the control group included 40 children with renal diseases who underwent total intravenous anaesthesia during renal biopsy at the hospital within the same period. Hemodynamic parameters, such as mean arterial pressure (MAP), heart rate (HR), and oxygen saturation (SPO2), were assessed at four different time points: Before anesthesia induction (T0), during anesthesia induction (T1), after anesthesia induction (T2), and at the conclusion of the surgery (T3). Puncture success rate, time to renal puncture, time to get out of bed, postoperative recovery from anaesthesia (including time to postoperative awakening and time to return to spontaneous respiration) and incidence of adverse anaesthetic reactions were also included. RESULTS: We observed notable variations in HR and MAP at T2 and T3, as well as SPO2 levels, duration of awakening from anaesthesia and time taken to resume spontaneous respiration between the two groups at T2 (p < 0.05). No statistically significant variances were detected between the two groups concerning adverse reactions to anaesthesia, puncture success rate, duration to renal puncture and time to mobilisation from bed (p > 0.05). CONCLUSIONS: In conclusion, compared with the total intravenous anaesthesia, the implementation of the sedation-aspiration-combined anaesthesia in renal biopsy in children with renal disease features less haemodynamic fluctuation, better postoperative anaesthesia recovery and does not increase the incidence of adverse reactions.

Mortality and morbidity after total intravenous anaesthesia versus inhalational anaesthesia: a systematic review and meta-analysis.

Background: General anaesthesia is provided to more than 300 million surgical patients worldwide, every year. It is administered either through total intravenous anaesthesia, using only intravenous agents, or through inhalational anaesthesia, using volatile anaesthetic agents. The debate on how this affects postoperative patient outcome is ongoing, despite an abundance of published trials. The relevance of this topic has grown by the increasing concern about the contribution of anaesthetic gases to the environmental impact of surgery. We aimed to summarise all available evidence on relevant patient outcomes with total intravenous anaesthesia versus inhalational anaesthesia. Methods: In this systematic review and meta-analysis, we searched PubMed/Medline, Embase and Cochrane Central Register of Controlled trials for works published from January 1, 1985 to August 1, 2023 for randomised controlled trials comparing total intravenous anaesthesia using propofol versus inhalational anaesthesia using the volatile anaesthetics sevoflurane, desflurane or isoflurane. Two reviewers independently screened titles, abstracts and full text articles, and assessed risk of bias using the Cochrane Collaboration tool. Outcomes were derived from a recent series of publications on consensus definitions for Standardised Endpoints for Perioperative trials (StEP). Primary outcomes covered mortality and organ-related morbidity. Secondary outcomes were related to anaesthetic and surgical morbidity. This study is registered with PROSPERO (CRD42023430492). Findings: We included 317 randomised controlled trials, comprising 51,107 patients. No difference between total intravenous and inhalational anaesthesia was seen in the primary outcomes of in-hospital mortality (RR 1.05, 95% CI 0.67-1.66, 27 trials, 3846 patients), 30-day mortality (RR 0.97, 95% CI 0.70-1.36, 23 trials, 9667 patients) and one-year mortality (RR 1.14, 95% CI 0.88-1.48, 13 trials, 9317 patients). Organ-related morbidity was similar between groups except for the subgroup of elderly patients, in which total intravenous anaesthesia was associated with a lower incidence of postoperative cognitive dysfunction (RR 0.62, 95% CI 0.40-0.97, 11 trials, 3834 patients) and a better score on postoperative cognitive dysfunction tests (standardised mean difference 1.68, 95% CI 0.47-2.88, 9 trials, 4917 patients). In the secondary outcomes, total intravenous anaesthesia resulted in a lower incidence of postoperative nausea and vomiting (RR 0.61, 95% CI 0.56-0.67, 145 trials, 23,172 patients), less emergence delirium (RR 0.40, 95% CI 0.29-0.56, 32 trials, 4203 patients) and a higher quality of recovery score (QoR-40 mean difference 6.45, 95% CI 3.64-9.25, 17 trials, 1835 patients). Interpretation: The results indicate that postoperative mortality and organ-related morbidity was similar for intravenous and inhalational anaesthesia. Total intravenous anaesthesia offered advantages in postoperative recovery. Funding: Dutch Society for Anaesthesiology (NVA).

[Experiences with pain control during piglet castration in Switzerland Part 1: Inhalation anesthesia]. / Erfahrungen zur Schmerzausschaltung bei der Ferkelkastration in der Schweiz Teil 1: Inhalationsanästhesie.

The objectives of this study were a description of the practical implementation of the painless castration under inhalational anaesthesia with an objective assessment of animal welfare, workplace safety and time exposure. 600 questionnaires were sent to farmers all over Switzerland and 100 farms were visited during castration under inhalation anaesthesia. 44 % of the visited farmers administered analgetics during anaesthesia or less than 10 minutes before castration. 14 % of the piglets were insufficiently anaesthetised (moving or vocalising) and 18 % showed stronger bleeding tendency after castration. The mortality rate was less than 0.1 %. 22 % of the swine farmers reported headache or dizziness during or after castration work. The Isoflurane level on 2 farms was above the Swiss safety limits. The time needed for castration was with 4.3 minutes clearly above the time necessary without anaesthesia. The additional financial costs and time are at the moment not adequately compensated to the farmers.

Le but de la présente étude était de décrire la mise en application en Suisse de la castration indolore des porcelets sous anesthésie par inhalation et d'étudier les aspects de protection des animaux, de sécurité à la place de travail ainsi que de l'investissement en temps pour cette castration. On a envoyé 600 questionnaires à des producteurs de porcelets dans toute la Suisse (taux de retour 40.5 %) et 100 exploitations ont été visitées lors de castrations sous anesthésie par inhalation. Sur 44 % des exploitations visitées, un analgésique était appliqué soit pendant l'anesthésie soit moins de 10 minutes avant la castration. 14 % des porcelets montraient des réactions de défense ou des vocalisations causées par la castration et 18% présentaient une tendance augmentée aux saignements après la castration. La mortalité était inférieure à 0.1 %. 22 % des exploitants mentionnaient des céphalées ou des vertiges pendant ou après les castrations. Sur deux exploitations, les concentrations limites d'isoflurane admises en Suisse étaient dépassées. Le temps nécessaire pour une castration, y compris le pré- et le postopératoire, était, avec 4,3 minute, nettement supérieur à celui nécessaire pour une castration sans anesthésie. Les producteurs ne sont actuellement pas correctement indemnisés pour les surcoûts et l'investissement supplémentaire en temps.

Analysis of pH and Electrolytes in Blood and Electrolytes in Ruminal Fluid, including Kidney Function Tests, in Sheep Undergoing General Anaesthesia for Laparotomy.

BACKGROUND: Performing Sectio Caesarea in sheep under general anaesthesia is a common procedure in veterinary practice. The abdominal cavity can be accessed via linea alba, for which the ewe is positioned in the supine position, whereby rumen and uterus can compromise lung function. Although the rumen represents an important reservoir for fluid and electrolytes, and kidney function during anaesthesia is essential, these parameters have not been focused on in research. Therefore, the objective of this study is to contribute data on blood parameters, ruminal fluid, and kidney function tests during laparotomy. METHODS: Laparotomy was performed in 14 ewes, whereof five animals were pregnant ewes (PE) and nine non-pregnant ewes (NPE). A total of seven animals received isoflurane in addition to oxygen (inhalational anaesthesia (InhA)) and seven ewes were anaesthetised with xylazine and ketamine (total intravenous anaesthesia (TIVA)); all ewes received lumbosacral anaesthesia. Blood, urine, and ruminal fluid were sampled every hour over a three-hour period. RESULTS: On comparing InhA to TIVA, higher values were detected for TIVA in haemoglobin, paced cell volume, sodium, phosphate, glucose concentration in the blood, and phosphate in ruminal fluid. Lower values were detected for TIVA in partial pressure of oxygen, oxygen saturation, and creatinine clearance. On comparing PE to NPE, higher values were detected in PE in magnesium and ruminal calcium. Lower values in PE were detected in chloride, base excess in the blood, and ruminal phosphate. Over time, an increase in partial pressure of carbon dioxide, glucose in the blood, glucose in urine, and a decrease in protein and albumin could be observed. CONCLUSION: Surgery in sheep in the supine position should be performed with additional oxygen to maintain physiological pO2 and sO2 values. Kidney function could be maintained with a minimal electrolyte infusion regime. Additional glucose is not necessary, even in pregnant ewes. Further research should be conducted on parameters in ruminal fluid.

Comparison of Outcomes After Breast Cancer Surgery Between Inhalational and Propofol-Based Intravenous Anaesthesia: A Systematic Review and Meta-Analysis.

BACKGROUND: General anaesthesia is the commonly provided for breast cancer surgery, but the effects of inhalational anaesthesia and propofol-based intravenous anaesthesia on short- and long-term outcomes after breast cancer surgery are not clear. In this study, we conduct a meta-analysis of randomized controlled trials (RCTs) to explore the superior anaesthetic for breast cancer surgery patients. METHODS: We searched the Embase, Medline, Cochrane Library, Web of Science, CNKI, and Wanfang databases (up to January, 2021) for RCTs in which inhalational anaesthesia and propofol-based intravenous anaesthesia were compared and short- and long-term outcomes were assessed in breast cancer surgical patients. The meta-analysis was performed by Stata 12.0. RESULTS: Twenty RCTs with a total of 2201 patients were included. Compared with inhalational anaesthesia, propofol-based intravenous anaesthesia was associated with more postoperative rescue analgesia (I2 =0%, RR: 1.18, 95% CI: 1.07-1.30, P=0.001) but a lower incidence of postoperative nausea and vomiting (PONV) (I2 =25.5%, RR: 0.71, 95% CI: 0.62-0.81, P<0.001) and postoperative rescue antiemetics (I2 =0%, RR: 0.69, 95% CI: 0.58-0.82, P<0.001). Propofol-based intravenous anaesthesia preserved nature killer cell cytotoxicity (I2 =86.2%, SMD: 0.76, 95% CI: 0.13-1.39, P=0.018), decreased IL-6 level (I2 =98.0%, SMD: -3.09, 95% CI: -5.70- -0.48, P=0.021) and neutrophil-to-lymphocyte ratio (I2 =0%, SMD: -0.28, 95% CI: -0.53- -0.03, P=0.030), and increased 2-year recurrence-free survival rate (I2 =0%, RR: 1.10, 95% CI: 1.00-1.20, P=0.043) but did not affect recurrence or the overall survival rate (P>0.05). CONCLUSION: Propofol-based intravenous anaesthesia increases postoperative rescue analgesia but reduces PONV compared with inhalational anaesthesia in breast cancer surgery. The benefit of propofol over inhalational anaesthetics in the preservation of anti-cancer immunity is obvious, but it is difficult to conclude that propofol can exert long-term benefits due to the small sample size.

Comparison of recovery characteristics with two different washout techniques of desflurane anaesthesia: A randomised controlled trial.

BACKGROUND: Rapid emergence with low soluble inhalational agents (IA) is offset by a significant association with emergence agitation (EA). Research on the influence of elimination methods of IA on recovery characteristics is very few. We conducted this study to compare the recovery characteristics of slow elimination (SE) of desflurane with purging technique. METHODOLOGY: Forty-five participants, 18-60 years, undergoing elective laparoscopic surgeries were randomised either into Group-P (n = 23) or Group-SE (n = 22). A standardised induction-maintenance protocol including desflurane and fresh gas flow (FGF) of 0.8 l/min was followed. During recovery, the FGF was increased in Group-P to 10 L/min and in Group-SE it was continued at 0.8 L/min. The decrement in end-tidal concentration of desflurane, time for emergence and extubation, EA and time for psychomotor recovery were noted. RESULTS: Time for emergence (Group-SE: 22.8 ± 9 vs. Group-P: 5.6 ± 1.5 min; P = 0.000) and emergence to extubation duration (Group-SE: 128 ± 36 s vs. Group-P: 11.5 ± 1.7 s; P = 0.000) were longer in the Group-SE than in Group-P. EA occurred in 22.7% patients in Group-SE and in 4.3% patients in Group-P (P = 0.07). Psychomotor recovery to baseline values was seen in more number of patients in Group-SE than Group-P at 30 min. There was no difference between the groups at 60 min post-extubation. CONCLUSIONS: Slow elimination using FGF of 0.8 L/min significantly prolongs emergence even with low soluble agent like desflurane. SE is not beneficial in decreasing the incidence of EA or hastening psychomotor recovery. Purging technique is, therefore, a better-suited technique with fewer complications for eliminating desflurane.

Timeliness of care and adverse event profile in children undergoing general anesthesia or sedation for MRI: An observational prospective cohort study.

BACKGROUND AND AIMS: Anaesthesia for children undergoing magnetic resonance imaging (MRI) ranges from moderate to deep sedation in order to facilitate uninterrupted completion of the scan. While various intravenous and inhalational techniques of anaesthesia have their own merits and demerits, there is a paucity of comparative literature between the two in children undergoing diagnostic MRI. MATERIALS AND METHODS: This prospective observational cohort study was conducted at the Radiology suite of a 2800-bedded tertiary care hospital, wherein 107 unpremedicated children between the ages of 6 months to 15 years received either sedation with propofol infusion (Group GSP, n = 57) or inhalational anaesthesia with a laryngeal mask airway (Group GAL, n = 50). Primary outcome measures included time to induction and time to recovery. Secondary outcomes comprised the incidence of respiratory and non-respiratory adverse events in the two groups. RESULTS: The median time to induction was significantly shorter in GSP than GAL [7.00 (IQR 5.0, 10.0) versus 10.00 minutes (IQR 8.8, 13.0), P < 0.001]; the incidence of desaturation [8 (16.0%) in GAL, 1 (1.8%) in GSP, P = 0.012], laryngospasm [11 (22.4%) in GAL, 1 (1.8%) in GSP, P = 0.001] and emergence delirium (5 (10%) in GAL, 0 in GSP, P = 0.047) were significantly greater in the GAL group. There was no difference in the time to emergence, nausea and vomiting or bradycardia between the two groups. CONCLUSION: Sedation with propofol infusion during paediatric MRI scan offers a short turnover time and favourable adverse event profile when compared to inhalational anaesthesia with an LMA.

Elevated Waste Anaesthetic Gas Concentration in the Paediatric Post-Anaesthesia Care Unit.

OBJECTIVE: Exposure to waste anaesthetic gas (WAG) is a recognised occupational hazard for health care professionals (HCP). In recovery rooms, scavenging and ventilation systems differ from those in the operating room, raising the question as to how efficient they are. This study aims to measure the levels of ambient sevoflurane over the course of consecutive workdays in the paediatric recovery room of a tertiary academic centre. METHODS: The following is a descriptive-analytic study of ambient air sevoflurane levels measured using a MIRAN® 205B Series SapphIRe portable ambient air analyser. Samples were obtained between 7:30 am and 6:30 pm for two non-consecutive weeks on consecutive weekdays in our paediatric recovery room area. RESULTS: The ambient air levels of sevoflurane exceeded the ceiling concentration of 0.5 ppm recommended by the National Institute for Occupational Safety and Health on all days of measurement. The concentration of sevoflurane in ambient air correlates directly with the number of patients present. CONCLUSION: Even in a modern recovery room constructed according to current building standard and code, ambient air levels of WAG exceed the recommendations. Future research and practice standards are needed to reduce this occupational exposure. Disregarding whether chronic exposure to WAG is harmful, we have shown that HCP working in recovery rooms are chronically exposed to concentrations which exceed recommended levels. Strategies are needed to reduce ambient levels of WAG in post-anaesthesia care units.

Target-controlled inhalation anaesthesia: A cost-benefit analysis based on the cost per minute of anaesthesia by inhalation.

BACKGROUND: End-tidal target-controlled inhalational anaesthesia (TCIA) with halogenated agents (HA) provides a faster and more accurately titrated anaesthesia as compared to manually-controlled anaesthesia. This study aimed to measure the macro-economic cost-benefit ratio of TCIA as compared to manually-controlled anaesthesia. METHODS: This retrospective and descriptive study compared direct drug spending between two hospitals before 2011 and then after the replacement of three of six anaesthesia machines with TCIA mode machines in 2012 (Aisys carestation®, GE). The direct costs were obtained from the pharmacy department and the number and duration of the anaesthesia procedures from the computerized files of the hospital. RESULTS: The cost of halogenated agents was reduced in the hospital equipped with an Aisys carestation® by 13% as was the cost of one minute of anaesthesia by inhalation (€0.138 and €0.121/min between 2011 and 2012). The extra cost of the implementation of the 3 anaesthesia machines could be paid off with the resulting savings over 6 years. DISCUSSION: TCIA appears to have a favourable cost-benefit ratio. Despite a number of factors, which would tend to minimise the saving and increase costs, we still managed to observe a 13% savings. Shorter duration of surgery, type of induction as well as the way HA concentration is targeted may influence the savings results obtained.

Effects of a constant rate infusion of medetomidine-propofol on isoflurane minimum alveolar concentrations in horses.

The aim of this investigation was to determine the isoflurane-sparing effect and impact on arterial blood pressure and anaesthetic recovery of a constant rate infusion of medetomidine-propofol in horses. In a prospective, crossover, randomised study, six healthy horses (mean ± SD age, 13.7 ± 7.7 years; weight, 433 ± 51 kg) were anaesthetised twice with isoflurane and were randomly assigned to receive one of two treatments on each occasion, at least 2 weeks apart. The first treatment was saline (CTL group) and the second a medetomidine-propofol infusion (MP group; 1.25 µg/kg/h medetomidine and 3 mg/kg/h propofol). The isoflurane minimum alveolar concentration (MAC) was determined and the reduction in anaesthetic requirements was calculated. Cardiopulmonary data were recorded at different intervals during the procedure and anaesthetic recovery was blindly assessed using three independent scales. The MAC in the MP group (0.43 ± 0.08%) was 65% lower than in the CTL group (1.23 ± 0.10%). The MP group had a higher mean arterial blood pressure and required less dobutamine than the CTL group. The recovery quality in both groups was considered fair or good and an improvement was observed using the Donaldson scale in the MP group. The administration of a medetomidine-propofol constant rate infusion reduced anaesthetic isoflurane requirements to a clinically significant extent and improved stability of arterial blood pressure together with a good quality recovery. This regime could be useful for providing balanced anaesthesia in horses.