Isoflurane In Oxygen Research Articles

Effect of preoxygenation before isoflurane induction and rocuronium-induced apnea on time until hemoglobin desaturation in domestic chickens (Gallus gallus domesticus)

ObjectiveTo evaluate the time to hemoglobin oxygen desaturation in chickens (Gallus gallus domesticus) with and without preoxygenation before isoflurane induction of anesthesia and rocuronium-induced apnea. Study designProspective, randomized crossover study. AnimalsA total of 10 healthy adult Lohmann Brown-Lite hens. MethodsHens were anesthetized with isoflurane for intravenous (IV) and intraarterial catheter placement and allowed to fully recover from anesthesia. Hens in the preoxygenation treatment were administered oxygen (2 L minute–1) via a facemask for 3 minutes prior to induction of anesthesia with 3% isoflurane in oxygen. In the alternative treatment, hens were not preoxygenated prior to induction of anesthesia with isoflurane in oxygen. Apnea was then induced with rocuronium bromide (1.0 mg kg–1) administered IV, and anesthesia was maintained with IV propofol infusion. A cloacal pulse oximeter measured hemoglobin oxygen saturation (SpO2). Time was recorded from the start of apnea until SpO2 was 90% (desaturation). The trachea was intubated, and anesthesia was maintained with isoflurane in oxygen with manual ventilation until spontaneous breathing returned and SpO2 ≥ 99%. PaO2 was measured before each treatment, after preoxygenation, postinduction and at desaturation. Data were analyzed between treatments using Wilcoxon matched-pairs signed rank tests with Holm-Šidák multiple comparison test, and within treatments using Friedman test with Dunn’s multiple comparison test (p < 0.05). Data are reported as median (range). ResultsTime from start of apnea until hemoglobin desaturation was not significantly different between preoxygenated and nonpreoxygenated hens [26.5 (16–50) seconds and 24.0 (5–57) seconds, respectively; p = 0.25]. No differences in PaO2 between treatments were observed at any time point. Conclusions and clinical relevancePreoxygenation for 3 minutes before isoflurane mask induction of anesthesia and apnea does not significantly increase time until desaturation in hens.

Persistent hypotension resolved by neostigmine administration in a dog in which atracurium was used

AbstractA dog with a large abdominal mass underwent coeliotomy. Before surgery, the dog was anaemic, hypoalbuminaemic and had a grade III out of VI left sided holosystolic heart murmur; no signs related to heart failure were detected on thoracic radiographs. After intramuscular administration of methadone, anaesthesia was induced intravenously (IV) with fentanyl and propofol and maintained with isoflurane in oxygen. Lungs were mechanically ventilated using a volume‐controlled setting. To manage ventilation asynchrony, atracurium was administered IV. Concurrent hypotension did not respond to lowering the isoflurane concentration, crystalloid and colloid boluses administration, and dobutamine infusion. Surgery lasted 40 minutes, and the mass was easily removed. At end of surgery, neostigmine was administered IV slowly, and a progressive improvement of arterial blood pressure was recorded. The animal was then allowed to breathe spontaneously, and isoflurane was discontinued. Recovery from general anaesthesia was uneventful.

Evaluation of supraglottic airway device use during inhalation anesthesia in healthy African pygmy hedgehogs (Atelerix albiventris)

ObjectiveTo evaluate a supraglottic airway device (SGAD) designed for rabbits in African pygmy hedgehogs (Atelerix albiventris) during inhalation anesthesia. Study designProspective, randomized, blinded experimental study. AnimalsA total of 12 adult African pygmy hedgehogs (seven male, five female). MethodsHedgehogs were placed in a chamber and anesthesia was induced using isoflurane in oxygen. Oropharyngeal endoscopy was performed and video recorded. The SGAD (v-gel R1) was inserted and connected to a Mapleson D circuit. Capnography, pulse oximetry and physiologic variables were measured during anesthesia, and lung inflation was tested at 10 and 20 cmH2O. With the SGAD temporarily disconnected, anesthetized hedgehogs were randomly positioned into right and left lateral, dorsal and sternal recumbency to evaluate the effect of a change in body position on SGAD placement. Oropharyngeal endoscopy was repeated at the end of anesthesia, and recovery time was recorded. Pre- and post-SGAD placement endoscopy videos were retrospectively reviewed and scored for gross trauma. ResultsThe median [interquartile range (IQR)] time to successful SGAD placement was 38 (16–68) seconds. The time to SGAD placement decreased as the study progressed. SGAD required repositioning in six hedgehogs, median 2.5 (IQR, 1–3.5) adjustments each, to successfully perform lung inflation or maintain capnography readings. Lung inflation at 10 cmH2O was successfully performed without leakage in nine animals, and in the other three animals after adjusting the SGAD at 1–2 time points. Inflation at 20 cmH2O was rarely achieved without an air leak. Changes in heart and respiratory rates during anesthesia were not clinically relevant. Median endoscopic scores were 0 (no lesions) for both pre-and postplacement. Conclusions and clinical relevanceThe SGAD was relatively quickly and easily placed, permitted lung inflation and caused no significant oropharyngeal damage. The SGAD is a practical option for airway management in African pygmy hedgehogs.

Intraoperative Assessment of Fluid Responsiveness in Normotensive Dogs under Isoflurane Anaesthesia.

The aim of this study was to evaluate the incidence of fluid responsiveness (FR) to a fluid challenge (FC) in normotensive dogs under anaesthesia. The accuracy of pulse pressure variation (PPV), systolic pressure variation (SPV), stroke volume variation (SVV), and plethysmographic variability index (PVI) for predicting FR was also evaluated. Dogs were anaesthetised with methadone, propofol, and inhaled isoflurane in oxygen, under volume-controlled mechanical ventilation. FC was performed by the administration of 5 mL/kg of Ringer’s lactate within 5 min. Cardiac index (CI; L/min/m2), PPV, (%), SVV (%), SPV (%), and PVI (%) were registered before and after FC. Data were analysed with ANOVA and ROC tests (p < 0.05). Fluid responsiveness was defined as 15% increase in CI. Eighty dogs completed the study. Fifty (62.5%) were responders and 30 (37.5%) were nonresponders. The PPV, PVI, SPV, and SVV cut-off values (AUC, p) for discriminating responders from nonresponders were PPV >13.8% (0.979, <0.001), PVI >14% (0.956, <0.001), SPV >4.1% (0.793, <0.001), and SVV >14.7% (0.729, <0.001), respectively. Up to 62.5% of normotensive dogs under inhalant anaesthesia may be fluid responders. PPV and PVI have better diagnostic accuracy to predict FR, compared to SPV and SVV.

Successful prolonged cardiopulmonary resuscitation in a Siamese cat: A case of post‐cardiac arrest concerns

AbstractA 4.5‐year‐old male neutered Siamese cat was admitted to referral hospital for medical work‐up of chronic anorexia and emesis. No severe abnormalities were detected on routine blood work; however thickened gastric wall and small intestines were noted on abdominal ultrasonography. The cat was premedicated with buprenorphine followed by a diazepam‐propofol co‐induction. Endotracheal intubation was performed, and anaesthesia was maintained using isoflurane in oxygen for endoscopic investigation of the thickened gastric wall and biopsies retrieval. During the anaesthetic recovery, the animal went into cardiopulmonary arrest. Successful ROSC (return of spontaneous circulation) was achieved at approximate 40 minutes (prolonged) post‐arrest, and the animal had a survived event (ROSC &gt; 20 minutes). However, failure to identify the inciting cause of the CPA and laxity in the post‐cardiac arrest care resulted in rearrest of the cat, 77 hours after the initial ROSC with no success of a second ROSC.

Oxygen reserve index as a noninvasive indicator of arterial partial pressure of oxygen in anaesthetized donkeys: a preliminary study

ObjectiveTo evaluate the oxygen reserve index (ORI) as a noninvasive estimate of the PaO2 during moderate hyperoxaemia [100–200 mmHg (13.3–26.6 kPa)], and to determine ORI values identifying PaO2 > 100, > 150 (20.0 kPa) and > 200 mmHg in anaesthetized donkeys with an inspired fraction of oxygen (FiO2) > 0.95. Study designProspective observational study. AnimalsA group of 28 adult standard donkeys aged (mean ± standard deviation) 4 ± 2 years and weighing 135 ± 15 kg. MethodsDonkeys were sedated intramuscularly with xylazine and butorphanol; anaesthesia was induced with ketamine and diazepam and maintained with isoflurane in oxygen. An adhesive sensor probe was applied to the donkey’s tongue and connected to a Masimo pulse co-oximeter to determine ORI values. An arterial catheter was inserted into an auricular artery. After ORI signal stabilization, the value was noted and PaO2 determined by blood gas analysis. The Pearson correlation coefficient was used to assess the relationship between ORI and PaO2 for oxygen tension < 200 mmHg (< 26.6 kPa). The Youden index was used to identify the value of ORI that detected PaO2 > 150 and 200 mmHg (20.0 and 26.6 kPa) with the highest sensitivity and specificity. ResultsA total of 106 paired measurements were collected. A mild positive correlation was observed between ORI and PaO2 for values < 200 mmHg (26.6 kPa; r = 0.52). An ORI > 0.0, > 0.1 and > 0.3 indicated a PaO2 > 100, > 150 and > 200 mmHg (13.3, 20.0 and 26.6 kPa) with negative predictive values > 94%. Conclusions and clinical relevanceORI may provide a noninvasive indication of PaO2 > 100, > 150 and > 200 mmHg (13.3, 20.0 and 26.6 kPa) in anaesthetized donkeys with an FiO2 > 0.95, although it does not replace blood gas analysis for assessment of oxygenation.

Influence of peri-incisional epaxial muscle infiltration with bupivacaine pre- or post-surgery on opioid administration in dogs undergoing thoraco-lumbar hemilaminectomy

This study investigated the influence of bupivacaine infiltration before or after hemilaminectomy on peri-operative opioid requirement in dogs. Thirty dogs undergoing T3-L3 hemilaminectomy were randomly assigned to receive peri-incisional infiltration of bupivacaine 2 mg/kg into the epaxial muscles before surgery (Group A), at wound closure (Group B), or no infiltration (Group C). Anaesthesia comprised dexmedetomidine 4 mcg/kg and methadone 0.3 mg/kg IV (premedication), alfaxalone IV (induction), and isoflurane in oxygen (maintenance). All dogs received meloxicam SC/PO prior to induction of general anaesthesia. Response to surgery, defined as a change in autonomic physiological variables >20% above baseline, was treated with fentanyl 2.5 mcg/kg boluses, followed by a continuous rate infusion of fentanyl at 5 mcg/kg/h. The Glasgow Composite Pain Score–Short Form (GCPS-SF) was performed before premedication and at regular intervals until 24 h postoperatively. Methadone 0.2 mg/kg analgesia was given IV if GCPS-SF was ≥5/20. Number of intraoperative, postoperative and total analgesic interventions were recorded. Analgesic interventions were analysed using a chi–squared test using a Pocock approach and statistical significance was set at P < 0.029.The number of intra-operative analgesic interventions in Group A (median, 0; range, 0–2), was significantly lower than in Group B (median, 3; range, 0–5) and Group C (median, 3; range, 0–5; P = 0.019). Regarding postoperative interventions, there were significantly fewer in Group A (median, 0; range, 0–1) and Group B (median, 0; range, 0–1) than in Group C (median, 1; range, 0–2; P = 0.047). Group A (median, 0; range, 0–3), had significantly fewer total analgesic interventions than Group B (median, 3; range, 0–6) and Group C (median, 4; range, 1–7; P = 0.014). Bupivacaine reduced peri-operative opioid administration and pre-surgical peri-incisional infiltration yielded the greatest benefit.

Effects of epidural bupivacaine, bupivacaine-butorphanol and bupivacaine-morphine on postoperative analgesia for hind limb and pelvic orthopedic operations in dogs

The aim of this study was to compare the postoperative analgesic effects of epidural bupivacaine, bupivacaine-butorphanol and bupivacaine-morphine in hind limb and pelvic orthopedic operations in dogs. Three groups each containing 10 dogs were formed. Through the lumbosacral space, group B was administered bupivacaine, 1 mg kg-1; group BB was administered bupivacaine, 1 mg kg-1 and butorphanol, 0.25 mg kg-1; and group BM was administered bupivacaine, 1 mg kg-1 and morphine, 0.1 mg kg-1. Anaesthesia was induced with diazepam (0.2 mg kg-1) and propofol (5 mg kg-1) and maintenance with isoflurane in oxygen. Pain assessment was performed with the University of Melbourne Pain Scale (UMPS) by a blinded observer. Plasma cortisol levels were measured preoperatively and postoperatively. Postoperative pain scores were significantly lower at 2 hours in the group BM, and at 8 and 12 hours in the groups BB and BM compared to the group B (P=0.007). Group BM had a lower plasma cortisol level than the group B at 2 hours (P=0.002). Bupivacaine-butorphanol and bupivacaine-morphine use were shown to provide longer analgesia in the postoperative period; and the epidural administration of bupivacaine-butorphanol and bupivacaine-morphine was considered to be potentially useful in clinical practice.

The effects of flumazenil on ventilatory and recovery characteristics in horses following midazolam-ketamine induction and isoflurane anaesthesia.

Flumazenil antagonises the actions of benzodiazepines. There has been no prior research specifically investigating this anaesthetic reversal agent for horses. To determine the effects of flumazenil administration in horses on (a) ventilatory parameters after midazolam-ketamine induction and maintenance with isoflurane in oxygen and on (b) the characteristics of recovery from general anaesthesia. Blinded, randomised, crossover experiment. Six horses were randomly assigned to receive high-dose flumazenil (Fhigh , 20µg/kg), low-dose flumazenil (Flow , 10µg/kg) and saline (control). Cardioventilatory parameters were monitored. After 90minutes of isoflurane anaesthesia, a bolus of Fhigh , Flow or saline was administered i.v. The horses were recovered using head and tail rope assistance. The times to first movement, to achievement of sternal recumbency, to the first attempt to stand and the total recovery time were determined. The recovery quality was evaluated using a 115-point recovery scoring system. The cardioventilatory parameters and recovery times were analysed using mixed-effects regression analyses. Intraclass correlation (ICC) analysis was used to evaluate the recovery scores. A Mann-Whitney U test assessed the relationship between recovery score and flumazenil administration. A significant difference with flumazenil administration was found for SpO2 , mean arterial pressure, I:E ratio, minute volume of ventilation (MV) and peak inspiratory pressure. There was a significant difference with flumazenil administration for the time to sternal recumbency, the time to the first attempt to rise and the total recovery time. There was no significant difference in total recovery score with flumazenil administration. Plasma levels of midazolam and flumazenil were not obtained. Flumazenil has a dose-dependent effect on MV and recovery time, which may make it useful in cases for which a prolonged anaesthetic recovery is undesirable.

Pharmacokinetics and pharmacodynamics of l-methadone in isoflurane-anaesthetized and mechanically ventilated ponies

ObjectiveTo evaluate the pharmacokinetics and selected pharmacodynamic effects of a commercially available l-methadone/fenpipramide combination administered to isoflurane anaesthetized ponies. Study designProspective single-group interventional study. AnimalsA group of six healthy adult research ponies (four mares, two geldings). MethodsPonies were sedated with intravenous (IV) detomidine (0.02 mg kg–1) and butorphanol (0.01 mg kg–1) for an unrelated study. Additional IV detomidine (0.004 mg kg–1) was administered 85 minutes later, followed by induction of anaesthesia using IV diazepam (0.05 mg kg–1) and ketamine (2.2 mg kg–1). Anaesthesia was maintained with isoflurane in oxygen. Baseline readings were taken after 15 minutes of stable isoflurane anaesthesia. l-Methadone (0.25 mg kg–1) with fenpipramide (0.0125 mg kg–1) was then administered IV. Selected cardiorespiratory variables were recorded every 10 minutes and compared to baseline using the Wilcoxon signed-rank test. Adverse events were recorded. Arterial plasma samples for analysis of plasma concentrations and pharmacokinetics of l-methadone were collected throughout anaesthesia at predetermined time points. Data are shown as mean ± standard deviation or median and interquartile range (p < 0.05). ResultsPlasma concentrations of l-methadone showed a rapid initial distribution phase followed by a slower elimination phase which is best described with a two-compartment model. The terminal half-life was 44.3 ± 18.0 minutes, volume of distribution 0.43 ± 0.12 L kg–1 and plasma clearance 7.77 ± 1.98 mL minute–1 kg–1. Mean arterial blood pressure increased from 85 (±16) at baseline to 100 (±26) 10 minutes after l-methadone/fenpipramide administration (p = 0.031). Heart rate remained constant. In two ponies fasciculations occurred at different time points after l-methadone administration. Conclusions and clinical relevanceAdministration of a l-methadone/fenpipramide combination to isoflurane anaesthetized ponies led to a transient increase in blood pressure without concurrent increases in heart rate. Pharmacokinetics of l-methadone were similar to those reported for conscious horses administered racemic methadone.

Retrospective investigation of an association between high-dose buprenorphine and perpetuation of post-anesthesia hyperthermia in cats following ovariohysterectomy.

We evaluated a potential association between the administration of high-dose buprenorphine and perpetuation of hyperthermia in cats following ovariohysterectomy (OVH). We hypothesized that buprenorphine 0.24 mg/kg subcutaneously (SC) would result in longer-lasting postoperative hyperthermia in cats vs a group receiving morphine 0.1 mg/kg SC. Anesthetic records from cats admitted for OVH as part of surgical exercises for second year veterinary medicine students in 2018 and 2019 were collected. All cats were sedated with dexmedetomidine 20 µg/kg and morphine 0.1 mg/kg intramuscularly. Anesthesia was induced with propofol and maintained with isoflurane in oxygen. At extubation, cats received morphine 0.1 mg/kg SC in 2018 and buprenorphine 0.24 mg/kg SC in 2019. Temperature was measured rectally prior to sedation, esophageally during anesthesia and rectally at 1, 4 and 16-20 h after extubation. Demographic data and temperature prior to administration of postoperative opioids were compared with t-tests. The effects of treatment (opioids) and time on postoperative rectal temperature and on the incidence of hyperthermia (temperature >39.2°C) were evaluated with mixed and generalized linear mixed-effect models. Significance was set at P <0.05. There were no differences in demographic characteristics between treatment groups (all P ⩾0.2). Intraoperative esophageal temperature was lower in cats scheduled to receive morphine (mean ± SD 36.6 ± 0.2) than in those receiving buprenorphine (36.9 ± 1.0) (P <0.0001). Postoperative temperature was higher for cats receiving buprenorphine than for those receiving morphine (P <0.0001). The incidence of hyperthermia 16-20 h after opioid administration was 56% for morphine and 73% for buprenorphine (P = 0.03). Buprenorphine 0.24 mg/kg SC for postoperative analgesia in cats was associated with hyperthermia that persisted for 16-20 h after administration, and the incidence of hyperthermia for this group was higher than in the cats that received morphine 0.1 mg/kg SC.

Arterial oxygenation in anesthetized horses placed in a 5-degree reverse Trendelenburg position

Low arterial oxygen is a common complication in anesthetized horses and placing the animal in reverse Trendelenburg (RT) position may treat hypoxemia. The objective of this study was to assess the arterial partial pressure of oxygen (PaO2) in horses placed in a 5-degree RT compared to horizontal (H) position. Client-owned healthy horses (n = 60) undergoing elective surgeries were enrolled in a randomized controlled clinical study. Horses were sedated with butorphanol, an α2-adrenoceptor agonist, ± acepromazine and induced with ketamine combined with a benzodiazepine, propofol, or guaifenesin. Anesthesia was maintained with isoflurane in oxygen with mechanical ventilation. Each group (RT and H) included 30 horses, 10 in each recumbency (dorsal, right and left lateral). Arterial blood gas analyses (aBG) were performed following arterial catheter placement then hourly. Time first-to-last aBG, changes in PaO2, dynamic compliance (Cdyn), estimated pulmonary shunt fraction (F-shunt), and alveolar dead space to tidal volume ratio (VD/VT) were evaluated with a 2-way analysis of variance. Statistical significance was set at p < .05. Overall, PaO2 increased in all groups; however no significant difference was found between recumbencies (dorsal, right and left lateral) and RT versus H in changes over time for PaO2 (p = .064 and p = .070, respectively), Cdyn (p = .721 and p = .672, respectively), F-shunt (p = .055 and p = .054, respectively), or VD/VT (p = .616 and p = .064, respectively). In healthy anesthetized horses, 5-degree RT did not affect changes in PaO2 as compared to H position.

Development of a lateral ultrasound-guided approach for the radial, ulnar, median and musculocutaneous (RUMM) nerve block in a calf undergoing surgical fixation of the antebrachium

A 26-day-old Pustertaler Sprinzer calf was referred to the ruminant clinic of the Veterinary University of Vienna for internal fixation of a suspected traumatic radius–ulnar fracture of the left forelimb....

Evaluation of tumescent local anesthesia in cats undergoing unilateral mastectomy

ObjectiveTo evaluate the analgesic efficacy and safety of tumescent local anesthesia (TLA) in cats undergoing unilateral mastectomy. Study designProspective clinical trial. AnimalsA total of 12 ovariohysterectomized female cats. MethodsAll animals were premedicated with pethidine (4 mg kg–1) intramuscularly (IM), followed by induction of anesthesia with propofol (5 mg kg–1) intravenously and maintenance with isoflurane in oxygen. A refrigerated TLA solution (15 mL kg–1, 8 °C) was injected using a Klein cannula. The solution was composed of 0.5 mL of epinephrine (1 mg mL–1) and 40 mL of 2% lidocaine added to 210 mL lactated Ringer’s solution (final lidocaine concentration 0.32%). Heart and respiratory rates, systolic arterial blood pressure, temperature and oxygen saturation were measured during anesthesia. Blood samples were collected from the jugular vein for measurement of plasma lidocaine concentration using high performance liquid chromatography. Postoperative pain scores were evaluated hourly for 6 hours. Analgesic rescue was performed with tramadol (2 mg kg–1) IM and meloxicam (0.15 mg kg–1) subcutaneously. ResultsPlasma lidocaine concentration peaked at 90 minutes after injection of TLA, but no concentration considered toxic for the species was measured. The median postoperative analgesia time was 6 hours after injection of TLA. ConclusionsThis study found that TLA prevented sympathetic response to noxious stimuli during anesthesia and provided satisfactory postoperative analgesia in cats submitted to total unilateral mastectomy, with no apparent signs of toxicity. Clinical relevanceTLA can prevent sympathetic stimulation resulting from noxious stimuli during anesthesia, promoting good intraoperative conditions, proving to be a viable addition to analgesia in cats submitted to a total unilateral mastectomy.

Balloon dilation of a perforated cor triatriatum dexter in a Springer Spaniel: anaesthetic management

A four-month-old male Springer Spaniel presented for investigation of ascites of three weeks’ duration. On transthoracic echocardiogram, cor triatriatum dexter was diagnosed with associated right-sided congestive heart failure. Medical therapy...

SURGICAL ORCHIECTOMY IN FRUIT BATS-DESCRIPTION OF TWO TECHNIQUES IN THE RUWENZORI LONG-HAIRED FRUIT BAT (ROUSETTUS LANOSUS) AND THE JAMAICAN FRUIT-EATING BAT (ARTIBEUS JAMAICENSIS).

Contraception is needed to prevent overpopulation and inbreeding in highly fecund captive bat colonies. Reports on surgical contraception in bats are limited. The objective of this study was to describe surgical castration techniques in a megachiropteran and a microchiropteran fruit bat species. Open orchiectomy by transfixing ligation of the spermatic cord was performed in 14 Ruwenzori long-haired fruit bats (Rousettus lanosus) (RL-LIG), and orchiectomy with radiosurgery alone was performed in 125 Jamaican fruit-eating bats (Artibeus jamaicensis) (AJ-RS) and one Ruwenzori bat (RL-RS). The surgical techniques were not compared in different species with the exception of the one Ruwenzori bat operated with RS. Anesthesia was induced and maintained with isoflurane in oxygen via facemask. Preoperatively, all bats received butorphanol and subcutaneous fluids. Meloxicam was administered postoperatively for the RL-LIG. For the RL-LIG, anesthesia lasted 49 ± 15 min (mean ± SD) with a total surgery time of 26 ± 12 min. In comparison, the RS was considerably shorter, lasting 10 ± 3 min for anesthesia and 5 ± 2 min for surgery. Complications were rare, with a morbidity rate of 6.7% with the RL-LIG (prolonged recovery [n = 1]) and of 4.8% with the RS (dyspnea [n = 3], hemorrhage [n = 2], and prolonged recovery [n = 1]). One of the cases of hemorrhage was in the single Ruwenzori bat castrated using the RS technique. Mortality rate was 1.6% (n = 2) with the RS. No mortality occurred with the RL-LIG. In conclusion, using radiosurgery alone appears to be a safe and rapid surgical technique in smaller species of fruit bats. For larger species, such as the Ruwenzori fruit bats, ligation or use of an advanced vessel sealing system is recommended.

Effect of non-steroidal anti-inflammatory drugs on glomerular filtration rate and urinary N-acetyl-β-D-glucosaminidase activity in cats after dental surgery

ObjectiveTo compare the effects of meloxicam or carprofen on glomerular filtration rate (GFR), and to evaluate the effect of meloxicam on urinary N-acetyl-β-D-glucosaminidase (NAG) activity, of cats after dental surgery. Study designRandomized, blinded, controlled trial. AnimalsA total of 24 mixed breed cats. MethodsCats were randomly assigned to one of three groups (n = 8 per group): meloxicam (0.2 mg kg–1); carprofen (4 mg kg–1); or saline (2 mL). Acepromazine (0.04 mg kg–1) and buprenorphine (0.02 mg kg–1) were administered intramuscularly as preanaesthetic medication. Test drugs were injected subcutaneously at the time of preanaesthetic medication. Anaesthesia was induced with intravenous propofol and maintained with isoflurane in oxygen. Mean arterial blood pressure (MAP), respiratory rate (fR), heart rate (HR) and haemoglobin oxygen saturation values (SpO2) were recorded. All cats underwent ultrasonic dental scaling with polishing. Teeth extraction involved mucosal flap creation, removal of alveolar bone and flap closure. Plasma iohexol clearance (ICL), a measure of GFR, was estimated before and 24 hours after anaesthesia induction in all cats. Urinary NAG index was estimated in saline and meloxicam groups at the same time points as GFR. Between-group and -time point differences in GFR and NAG index were compared using mixed model analyses. Data are presented as mean ± standard deviation (p < 0.05). ResultsThere was no significant difference in plasma ICL rate (range: from 1.22 ± 0.05 to 1.27 ± 0.04 mL kg minute–1) between groups or between time points. Urinary NAG index (range: from 1.0 ± 0.19 to 1.36 ± 0.29 Units gram–1) was not significantly different between meloxicam and saline groups. MAP, HR, fR and SpO2 did not differ significantly between groups. Conclusions and clinical relevanceMeloxicam and carprofen appeared to produce nonsignificant effects on GFR, and meloxicam did not affect the urinary NAG activity, of cats after dental surgery.

Use of metamizole as an additional analgesic during umbilical surgery in calves

ObjectiveTo investigate the effect of metamizole on physiologic variables in calves undergoing surgical extirpation of the navel during anaesthesia using xylazine, ketamine and isoflurane. Study designDouble-blind, randomized trial. AnimalsA total of 26 calves. MethodsCalves with uncomplicated umbilical hernias and otherwise clinically healthy were randomly allocated to one of two groups: the control group (CG) and metamizole group (MG). All calves were administered meloxicam (0.5 mg kg–1) intravenously (IV) 150 minutes before skin incision (SI). Animals were premedicated with xylazine (0.2 mg kg–1) intramuscularly 50 minutes before SI. Anaesthesia was induced with ketamine (2 mg kg–1) IV 30 minutes before SI and maintained with isoflurane in oxygen. MG calves were given metamizole (40 mg kg–1) IV 60 minutes before SI. CG calves were administered an equivalent volume of saline. Heart rate (HR) and mean arterial blood pressure (MAP) were recorded from 5 minutes before SI until the end of anaesthesia (60 minutes after SI). Blood samples for determination of the plasma cortisol concentration (PCC) were drawn 60 minutes before SI and at 5, 30, 60, 150, and 510 minutes after SI. ResultsIn both groups, PCC increased during surgery and decreased after surgery. PCC was consistently lower in MG than in CG and was significantly (p = 0.0026) lower at 150 minutes after SI in the MG. Overall, the mean PCC in MG was 10.9 nmol L–1 lower than that in CG (p = 0.01). In both groups, HR decreased during anaesthesia, whereas MAP increased, albeit with no statistically significant (p > 0.05) differences between groups. Conclusions and clinical relevanceOur study results suggest that a single preoperative dose of metamizole may have a positive impact on intra- and immediate postoperative analgesia by reducing PCC when used as an indicator of nociception.

Anaesthetic management and complications of transvascular patent ductus arteriosus occlusion in dogs

ObjectiveTo retrospectively analyse the anaesthetic management, complications and haemodynamic changes in a cohort of dogs undergoing transvascular patent ductus arteriosus (PDA) occlusion in a tertiary referral centre (from January 2017 to August 2018). Study designRetrospective study. AnimalsA total of 49 client-owned dogs. MethodsAnaesthetic records of dogs with PDA that underwent transvascular occlusion of the ductus were reviewed. Anaesthetic complications evaluated included tachycardia [heart rate (HR) > 160 beats minute–1], bradycardia (HR < 50 beats minute–1), hypertension [systolic arterial pressure (SAP) > 150 mmHg], hypotension [mean arterial pressure (MAP) < 60 mmHg], hypothermia (<37 °C) and the presence of arrhythmias. Cardiovascular variables [HR and invasive SAP, MAP and diastolic arterial pressure (DAP)] at the time of occlusion device deployment (time 0) were compared with variables at 5 and 10 minutes after deployment. Descriptive statistics, Shapiro–Wilk test and repeated measures analysis of variance followed by a Dunnett’s post hoc test were used to analyse the data (p < 0.05). ResultsCrossbreed dogs were the most commonly represented followed by the Cavalier King Charles Spaniel. The median age was 8 (2–108) months, and female dogs were over-represented (65.3%). The most common American Society of Anesthesiologists score was III. Mean duration of anaesthesia was 96 ± 26 minutes and mean surgery time was 58 ± 21 minutes. Acepromazine with methadone was the most commonly used premedication combination (77.6%). Propofol was the most common induction agent (73.5%). General anaesthesia was maintained with isoflurane in oxygen in all dogs. Complications included hypotension (63%), hypothermia (34%), bradycardia (28%), arrhythmias (16%), hypertension (16%) and haemorrhage (2%). MAP and DAP increased significantly 10 minutes after device deployment compared with time 0. Conclusionsand clinical relevance: Hypotension was the most common complication reported in dogs undergoing transvascular PDA occlusion. No major adverse events were documented.

Development of a severity scoring system for acute haemorrhage in anaesthetized domestic cats: the CABSS score

ObjectiveTo determine whether physiological, haematological, biochemical or electrolyte variables can predict severe haemorrhage in cats. Study designRandomized crossover study whereby each cat underwent mild and severe haemorrhage, with a 2 month period between events. AnimalsA group of six domestic cats aged 21 ± 1 months and weighing 4.9 ± 1.2 kg, mean ± standard deviation. MethodsCats were anaesthetized (buprenorphine, alfaxalone, isoflurane in oxygen at a fixed end-tidal concentration of 1.7%) before the haemorrhage event. In total, 34 variables were measured twice (prehaemorrhage and posthaemorrhage). The difference and percent change for each variable were compared between haemorrhage events (paired t test). Significant variables were placed into 13 different ratios (posthaemorrhage value of one variable divided by a posthaemorrhage value of a second variable) and compared (paired t test), and Cohen’s d (d) was calculated. Receiver operating characteristic curves were plotted and cut-off values for weak, moderate and strong indicators of severe haemorrhage were obtained. ResultsThe blood loss was 4.5 ± 1.1 mL kg–1 and 26.8 ± 5.5 mL kg–1 for mild and severe haemorrhage events, respectively. The most significant variables with large effect sizes were heart rate (HR), systolic arterial blood pressure (SAP), end-tidal carbon dioxide (Pe′CO2), serum albumin, haematocrit and actual bicarbonate ion concentration [HCO3−(act)]. The most robust ratios were: 1) shock index (d = –2.8; HR:SAP); 2) HR:Pe′CO2 (d = –2.9); 3) serum albumin: haematocrit (d = 1.5); and 4) HR:HCO3−(act) (d = –1.6). These ratios were included in the final proposed Cat Acute Bleeding Scoring System (CABSS). Conclusionsand clinical relevance Cats subjected to mild and severe haemorrhage demonstrated statistically and clinically relevant changes whereby four ratios could be created to make up the CABSS. The ratios detected and quantified the presence of severe haemorrhage in anaesthetized cats.