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Climate change is 'the biggest global health threat of the 21st century', and healthcare provision itself comes at an environmental cost. Volatile anaesthetic agents are potent greenhouse gases, but emissions arising from these waste anaesthetic gases can be dramatically reduced through a number of simple actions. This editorial lays out the options for more sustainable equine anaesthesia. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to compare the quality of anaesthesia and analgesia between methadone and buprenorphine in combination with medetomidine after induction with intramuscular (IM) alfaxalone in cats undergoing ovariohysterectomy. Methods: Fifty-one female cats (American Society of Anesthesiologists status I–II), with a median age of 12 months (range 2–60 months), weighing a mean ± SD of 2.5 ± 0.5 kg, were recruited to the study. Cats were randomly allocated to receive medetomidine (600 µg/m2) and buprenorphine (180 µg/m2) (group MB) or medetomidine (500 µg/m2) and methadone (5 mg/m2) (group MM) IM. Anaesthesia was induced 15 mins later using alfaxalone (3 mg/kg) IM. Anaesthesia was maintained with isoflurane in oxygen. All cats received meloxicam preoperatively. Quality of premedication and induction and intraoperative physiological parameters were recorded. Atipamezole (50% of medetomidine dose) was administered at the end of surgery. Cats were assessed postoperatively by the same blinded observer using a simple descriptive scale, numeric rating scale, dynamic interactive visual analogue scale (DIVAS) and UNESP-Botucatu multidimensional composite pain scales, at 10, 20 and 30 mins post-extubation. Parametric and non-parametric data were compared using Student's t -test or Mann–Whitney U-tests, respectively. Results: Forty-one cats completed the study. No significant differences were detected between groups before or during anaesthesia. No cats required rescue analgesia. DIVAS scores at 10 mins were significantly less in the MM group compared with the MB. No differences between groups at any other time points were detected using the four metrology instruments. Conclusions and relevance: Both protocols provided good anaesthesia conditions for ovariohysterectomy in the cat. [ABSTRACT FROM AUTHOR]

Background: Isoflurane is the only volatile anaesthetic agent licensed for equine use in the United Kingdom, but sevoflurane is also commonly used. The two agents have rarely been compared for use in clinical elective surgery. Methods: This single centre, prospective, randomised, blinded clinical investigation recruited 101 healthy client owned horses undergoing elective surgery. Anaesthesia was standardised and horses randomly assigned to receive isoflurane (I) or sevoflurane (S) for maintenance of anaesthesia in 100% oxygen. Horses were ventilated to normocapnia and received intravenous fluid therapy and haemodynamic support with dobutamine to maintain mean arterial blood pressure above 60 mm Hg. Recovery was timed and video‐recorded to allow offline evaluation by two experienced clinicians unaware of the volatile agent used. No post‐anaesthetic sedation was administered. Results: There was no significant difference between groups in terms of haemodynamic support required during anaesthesia nor in quality or duration of recovery. Inotropic support to maintain MAP above 60 mm Hg was required by 67 of 101 (67%) of horses. Five horses in the I group required additional ketamine or thiopentone to improve the plane of anaesthesia. Conclusions: Haemodynamic support needed during anaesthesia as well as the duration and quality of recovery were similar with isoflurane and sevoflurane. [ABSTRACT FROM AUTHOR]

Abstract Objective To characterize propofol anaesthesia in pregnant ponies. Animals Fourteen pony mares, at 256 ± 49 days gestation, undergoing abdominal surgery to implant fetal and maternal vascular catheters. Materials and methods Pre-anaesthetic medication with intravenous (IV) acepromazine (20 µg kg-1), butorphanol (20 µg kg-1) and detomidine (10 µg kg-1) was given 30 minutes before induction of anaesthesia with detomidine (10 µg kg-1) and ketamine (2 mg kg-1) IV Maternal arterial blood pressure was recorded (facial artery) throughout anaesthesia. Arterial blood gas values and plasma concentrations of glucose, lactate, cortisol and propofol were measured at 20-minute intervals. Anaesthesia was maintained with propofol infused initially at 200 µg kg-1 minute-1, and at 130–180 µg kg-1 minute-1 after 60 minutes, ventilation was controlled with oxygen and nitrous oxide to maintain PaCO2 between 5.0 and 6.0 kPa (37.6 and 45.1 mm Hg) and PaO2 between 13.3 and 20.0 kPa (100 and 150.4 mm Hg). During anaesthesia flunixin (1 mg kg-1), procaine penicillin (6 IU) and butorphanol 80 µg kg-1 were given. Lactated Ringer's solution was infused at 10 mL kg-1 hour-1. Simultaneous fetal and maternal blood samples were withdrawn at 85–95 minutes. Recovery from anaesthesia was assisted. Results Arterial blood gas values remained within intended limits. Plasma propofol levels stabilized after 20 minutes (range 3.5–9.1 µg kg-1); disposition estimates were clearance 6.13 ± 1.51 L minute-1 (mean ± SD) and volume of distribution 117.1 ± 38.9 L (mean ± SD). Plasma cortisol increased from 193 ± 43 nmol L-1 before anaesthesia to 421 ± 96 nmol L-1 60 minutes after anaesthesia. Surgical conditions were excellent. Fetal umbilical venous pH, PO2 and PCO2 were 7.35 ± 0.04, 6.5 ± 0.5 kPa (49 ± 4 mm Hg) and 6.9 ± 0.5 kPa (52 ± 4 mm Hg); fetal arterial pH, PO2 and PCO2 were 7.29 ± 0.06, 3.3 ± 0.8 kPa (25 ± 6 mm Hg) and 8.7 ± 0.9 kPa (65 ± 7 mm Hg), respectively. Recovery to standing occurred at 46 ± 17 minutes, and was generally smooth. Ponies regained normal behaviour patterns immediately. Conclusions and clinical relevance Propofol anaesthesia was smooth with satisfactory cardiovascular function in both mare and fetus; we believe this to be a suitable anaesthetic technique for pregnant ponies. [ABSTRACT FROM AUTHOR]

Objective To provide stable anaesthesia of long duration in broiler chickens in order to perform a terminal caecal ligated loop procedure. Study design Prospective experimental study. Animals Seven clinically healthy broiler chickens (Gallus domesticus) aged 27-36 days, weighing 884- 2000 g. Methods Anaesthesia was induced and maintained with isoflurane in oxygen. All birds underwent intermittent positive pressure ventilation for the duration. End-tidal carbon dioxide, peripheral haemoglobin oxygen saturation, heart rate and oesophageal temperature were monitored continuously. All birds received intraosseous fluids. Butorphanol (2 mg kg -1) was administered intramuscularly at two hourly intervals. Euthanasia by parenteral pentobarbitone was performed at the end of procedure. Results Stable anaesthesia was maintained in four chickens for durations ranging from 435 to 510 minutes. One bird died and one was euthanized after 130 and 330 minutes, respectively, owing to surgical complications and another died from anaesthetic complication after 285 minutes. Conclusions and clinical relevance Long-term, stable anaesthesia is possible in clinically healthy chickens, provided complications such as hypothermia and hypoventilation are addressed and vital signs are carefully monitored. There are no known previous reports describing monitored, controlled anaesthesia of this duration in chickens. [ABSTRACT FROM AUTHOR]

Abstract Objective To characterize intravenous anaesthesia with detomidine, ketamine and guaiphenesin in pregnant ponies. Animals Twelve pony mares, at 260–320 days gestation undergoing abdominal surgery to implant fetal and maternal vascular catheters. Materials and methods Pre-anaesthetic medication with intravenous (IV) acepromazine (30 µg kg-1), butorphanol (20 µg kg-1) and detomidine (10 µg kg-1) preceded induction of anaesthesia with detomidine (10 µg kg-1) and ketamine (2 mg kg-1) IV Maternal arterial blood pressure was measured directly throughout anaesthesia and arterial blood samples were taken at 20-minute intervals for measurement of blood gases and plasma concentrations of cortisol, glucose and lactate. Anaesthesia was maintained with an IV infusion of detomidine (0.04 mg mL-1), ketamine (4 mg mL-1) and guaiphenesin (100 mg mL-1) (DKG) for 140 minutes. Oxygen was supplied by intermittent positive pressure ventilation (IPPV) adjusted to maintain PaCO2 between 5.0 and 6.0 kPa (38 and 45 mm Hg), while PaO2 was kept close to 20.0 kPa (150 mm Hg) by adding nitrous oxide. Simultaneous fetal and maternal blood samples were withdrawn at 90 minutes. Recovery quality was assessed. Results DKG was infused at 0.67 ± 0.17 mL kg-1 hour-1 for 1 hour then reduced, reaching 0.28 ± 0.14 mL kg-1 hour-1 at 140 minutes. Arterial blood gas values and pH remained within intended limits. During anaesthesia there was no change in heart rate, but arterial blood pressure decreased by 10%. Plasma glucose and lactate increased (10-fold and 2-fold, respectively) and cortisol decreased by 50% during anaesthesia. Fetal umbilical venous pH, PO2 and PCO2 were 7.34 ± 0.06, 5.8 ± 0.9 kPa (44 ± 7 mm Hg) and 6.7 ± 0.8 kPa (50 ± 6 mm Hg); and fetal arterial pH, PO2 and PCO2 were 7.29 ± 0.06, 4.0 ± 0.7 kPa (30 ± 5 mm Hg) and 7.8 ± 1.7 kPa (59 ± 13 mm Hg), respectively. Surgical conditions were good but four ponies required a single additional dose of ketamine. Ponies took 60 ± 28 minutes to stand and recovery was good. Conclusions and clinical relevance Anaesthesia produced with DKG was smooth while cardiovascular function in mare and fetus was well preserved. This indicates that DKG infusion is suitable for maintenance of anaesthesia in pregnant equidae. [ABSTRACT FROM AUTHOR]