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 4 years 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 45 min 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 8 min 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 19.6 kg/45 min in intubated airways, between 7.9 and 16.3 kg/45 min in LMA, and between 3.6 and 22.3 kg/8 min 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.

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.

Descriptive Anatomy of the Porcine Ventral Abdominal Wall as a Basis for Training Ventral Hernia Repair Techniques.

Background: In recent times there has been a surge in innovative techniques concerning complex abdominal wall surgery. The availability of simulation models for comprehensive training and skill set development remains limited. Methods: Cadaveric dissections of the porcine abdominal wall were conducted to assess the suitability of anesthetized porcine models for training in both minimally invasive and open surgical procedures. Results: The panniculus carnosus, a typical muscular layer in mammals, is the outermost layer covering the anterolateral abdominal wall. Beneath it, there are four main pairs of abdominal wall muscles, mirroring the human anatomy. The rectus abdominis muscle runs straight along the linea alba and is surrounded by the rectus sheath, which is formed by the fusion of the lateral abdominal wall muscles and differs along the different regions of abdominal wall. The orientation of the muscle fibers in the lateral abdominal wall muscles, i.e., musculus obliquus externus, internus and transversus, is comparable to human anatomy. Although the transition lines between their muscular and aponeurotic part differ to some extent. Relevant for the adoption of surgical techniques, the transversus abdominis muscle is well-developed and resembles a bell curve shape as it transitions from its muscular to aponeurotic part. Conclusion: Despite minor differences in abdominal wall anatomy between pigs and humans, the porcine model provides a high level of fidelity in terms of both anatomical features and the development of skill sets relevant to hernia surgery.

Analytical validation of a high-sensitivity cardiac troponin T assay in horses.

Although cardiac troponin T (cTnT) assays have been used to detect myocardial damage in horses, a cTnT assay has not been analytically validated, to our knowledge. The aims of this study were to estimate the precision of a high-sensitivity cTnT assay in horses and determine the effect of hemolysis on the measured cTnT concentration. Serum samples from horses were mixed in 3 different pools. Pool 1 consisted of samples from 3 healthy horses, pool 2 from 6 horses with heart failure or atypical myopathy, and pool 3 from 10 horses with atypical myopathy. The within- and between-run coefficients of variation were determined for each pool. Pools 2 and 3 were diluted to estimate linearity. To study the influence of sample hemolysis, serum was collected from 4 horses with a high cTnT concentration, in which hemolysis was mechanically induced. In addition, ethylenediamine tetra-acetic acid blood tubes were collected from 3 other horses, from which hemolysate was prepared and added to plasma at different concentrations. The within- and between-run coefficients of variation of all pools were <10%, and a good linearity was found. Three out of 4 hemolyzed serum samples had a decreased serum cTnT concentration. Plasma samples with a high hemolysis index showed a negative interference, resulting in a lower cTnT concentration. Results of the high-sensitivity cTnT assay were highly reproducible. Because samples from horses with musculoskeletal damage were included, further studies should test the possible cross-reactivity between troponin T of musculoskeletal and cardiac origin before the assay can be used in equine clinical practice.

Veal Calves Produce Less Antibodies against C. Perfringens Alpha Toxin Compared to Beef Calves.

Enterotoxaemia is a disease with a high associated mortality rate, affecting beef and veal calves worldwide, caused by C. perfringens alpha toxin and perfringolysin. A longitudinal study was conducted to determine the dynamics of antibodies against these toxins in 528 calves on 4 beef and 15 veal farms. The second study aimed to determine the effect of solid feed intake on the production of antibodies against alpha toxin and perfringolysin. The control group only received milk replacer, whereas in the test group solid feed was provided. Maternal antibodies for alpha toxin were present in 45% of the veal calves and 66% of the beef calves. In beef calves a fluent transition from maternal to active immunity was observed for alpha toxin, whereas almost no veal calves developed active immunity. Perfringolysin antibodies significantly declined both in veal and beef calves. In the second study all calves were seropositive for alpha toxin throughout the experiment and solid feed intake did not alter the dynamics of alpha and perfringolysin antibodies. In conclusion, the present study showed that veal calves on a traditional milk replacer diet had significantly lower alpha toxin antibodies compared to beef calves in the risk period for enterotoxaemia, whereas no differences were noticed for perfringolysin.

Long-term follow-up of atrial function after cardioversion of atrial fibrillation in horses.

Atrial fibrillation (AF) causes atrial electrical and contractile remodelling in horses. The aim of this study was to quantify left atrial (LA) contractile function and its time course of recovery after cardioversion of naturally-occurring AF in horses. The study population included 42 AF horses which were successfully treated using transvenous electrical cardioversion TVEC (n=39) or quinidine sulfate (n=3), with trivial or mild mitral regurgitation present in 25 horses. Thirty-seven healthy horses were used as controls. AF duration was estimated based on the history and previous examinations. Echocardiography was performed during general anaesthesia after TVEC (day 0) and on days 1, 2, 6 and then 7 weeks after cardioversion. The two-dimensional (2D) echocardiographic measurements included LA diameter, area and ejection phase indices such as fractional shortening. Atrial TDI measurements included peak myocardial velocity during atrial contraction (A), time to onset A, time to peak A and duration of A. During follow-up after cardioversion, atrial contractile function measured by 2D echocardiography and TDI gradually improved. At 7 weeks following cardioversion, TDI-based myocardial velocities returned to reference values. However, AF horses still showed significantly larger atrial dimensions, lower 2D ejection phase indices and prolonged TDI-based conduction time compared to the control group. In conclusion, AF-induced atrial contractile dysfunction gradually improves in the weeks following cardioversion, but at 7 weeks post-cardioversion, significant differences remain compared to healthy controls.