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Background: TOF-Watch(®) monitors are designed to display train-of-four (TOF) count when neuromuscular block is intense, and to display TOF ratio when it is less intense. In dogs recovering from non-depolarizing neuromuscular block, when all four twitches are easily visible and apparently of similar magnitude, TOF-Watch(®) monitors often display TOF counts and not TOF ratios, as would be expected. We have never encountered this problem when the monitor was calibrated before neuromuscular blocking agent administration.Methods: Fourteen healthy female dogs undergoing ovariohysterectomy were investigated. Recovery from neuromuscular block was assessed with a calibrated TOF-Watch SX(®) monitor. When the TOF ratio returned to 90%, the TOF-Watch SX(®) was replaced with an uncalibrated TOF-Watch(®) monitor. The output obtained from the uncalibrated TOF-Watch(®) was compared with that of the calibrated device.Results: The median TOF ratio measured by the calibrated TOF-Watch SX(®) unit at recovery was 91 (86-100)% (n=14). The uncalibrated TOF-Watch(®) monitor displayed TOF counts in six dogs [2 (0, 4)] and TOF ratios in the remaining eight dogs [91 (79, 98)%], that is, the uncalibrated device failed to display appropriately >40% of the time.Conclusions: TOF-Watch(®) monitors must be calibrated before neuromuscular blocking agents are administered to dogs. When these devices are not so calibrated, they default to a reference value for twitch magnitude that was defined in healthy adult people. Even though neuromuscular transmission was restored in these dogs, we surmise that they did not achieve the default reference value, causing the monitor to display TOF counts rather than TOF ratios. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the hepatic effects of halothane in anesthetized goats and to compare them with those of isoflurane. [ABSTRACT FROM AUTHOR]

The purpose of this study was to find out if an LMA (#1 LMA-Classic) would provide a better airway than a face mask in spontaneously breathing anesthetized rabbits, and to test if it could be used for mechanically controlled ventilation. Sixteen rabbits (4.1 ± 0.8 kg, mean ± SD) were assigned randomly to three treatment groups; face mask with spontaneous ventilation (FM-SV; n = 5), LMA with spontaneous ventilation (LMA-SV; n = 5), and LMA with controlled ventilation (LMA-CV; n = 6). Rabbits were anesthetized in dorsal recumbency using a circle circuit at constant ET isoflurane (2.3%, Datex airway gas monitor) and constant rectal temperature (38.85 °C) for 2 hours. PaCO2 , PaO2 , minute volume, tidal volume (Wright's respirometer), and PeCO2 were measured at 15 minute intervals. Two individuals in the FM-SV group had PaCO2 >100 mm Hg (>13.3 kPa). One rabbit in the FM-SV had PaO2 <80 mm Hg (<10.7 kPa). All FM-SV rabbits showed signs of airway obstruction and two were withdrawn from the study at 45 and 90 minutes, respectively, because of cyanosis. Tidal volume could not be measured in the FM-SV group. No signs of airway obstructions were observed in either of the LMA groups. Four rabbits in the LMA-CV group developed gastric tympany, and one of these refluxed after 110 minutes. The significance of differences between the two spontaneously breathing groups and between the two LMA groups were measured using Wilcoxon's rank sum test (with significance assumed at p < 0.05). There were no statistical differences between FM-SV and LMA-SV in any variable tested. PaCO2 and Pe′CO2 were less in the LMA-CV group than in the LMA-SV group, while PaO2 , tidal volume, and minute volume were all more. We conclude that biologically, the LMA provides a better airway than the face mask during spontaneous breathing and that it can be used for IPPV, but that gastric tympany is likely to occur during IPPV. [ABSTRACT FROM AUTHOR]

Our purpose was to assess the accuracy and precision of a point of care hemoglobinometer (HemoCue-B hemoglobin photometer) for measuring hemoglobin concentration in horse blood. Samples of jugular venous blood from 12 healthy adult horses were collected in EDTA. In order to test the device over a wide range of values, each sample was divided into nine aliquots, and autologous plasma was added or removed from the aliquots to produce blood with PCV values that approximated 5, 10, 20, 30, 40, 50, 60, 70, and 80%, respectively. The aliquots were rocked to ensure mixing of plasma and cells. Then hemoglobin by HemoCue-B (HbHQ ) and hemoglobin by the cyanmethemoglobin method (HbCY ) were measured on each aliquot. The PCV of each aliquot was also measured and this value was used for subsequent analyses. To test repeatability, hemoglobin was measured twice by the HemoCue-B on approximately 40% samples. Samples with HbHQ >25.4 g dL-1 required dilution prior to analysis. HbCY ranged from 1.6 to 33.4 g dL-1 . After regression, HbCY = -0.16 + 1.04 HbHQ (n = 101; r 2 = 99.6%). By inspection of a modified Bland-Altman plot, HbHQ values <16 g dL-1 closely approximated HbCY ; however, at greater values, HbHQ underestimated HbCY by as much as 3.2 g dL-1 . The difference between repeated measurements with the HemoCue-B was 0.02 ± 0.16 g dL-1 (mean ± SD; n = 10) and nonsignificant. After regression, PCV = -0.76 + 2.78 HbHQ (n = 101; r 2 = 99.4%). We conclude that HemoCue-B can be used to measure hemoglobin concentration in horse blood, and that it is accurate when hemoglobin is <16 g dL-1 . PCV can be estimated by multiplying HbHQ by 2.8 and then subtracting 0.8. [ABSTRACT FROM AUTHOR]

The pre-medicant chosen may influence the ease with which gastroduodenoscopy (GD) is performed. The purpose of this study was to evaluate the relative ease of GD in cats under ketamine and isoflurane anesthesia after IM injection of hydromorphone (H, 0.1 mg kg-1 ), hydromorphone plus glycopyrrolate (HG, 0.1 mg kg-1 (H), 0.01 mg kg-1 (G)), medetomidine (M, 0.03 mg kg-1 ), or butorphanol (B, 0.4 mg kg-1 ). Eight cats were assigned randomly to receive each treatment in a cross-over design with at least 7 days between treatments. Twenty minutes after pre-medication, medetomidine produced greater (p = 0.001) sedation than the other treatments when assessed, using a subjective ordinal scale. The cats were injected with ketamine (10 mg kg-1 IM), orotracheally intubated, connected to a pediatric circle breathing system, and allowed to spontaneously breathe isoflurane in oxygen. Once end-tidal isoflurane concentration was stable at 1.4% for 15 minutes, endoscopy was started. A single endoscopist (REG), who was unaware of the treatment used, performed all endoscopies. The endoscopist scored the difficulty of endoscopy subjectively (0–3). The significance of differences between treatments was evaluated using Friedman's test. Time for entering the stomach was 9.4 (4.7–15.9) (median (minimum–maximum)), 6.6 (5.2–11.7), 8.4 (6.3–16.5), and 7.7 (5.1–14.7) seconds and for entering the duodenum from the stomach was 20.5 (13.8–40.9), 18.2 (10.3–39.8), 20.2 (16.2–119.5), and 22.2 (11.8–83.8) seconds for H, HG, M, and B treatments, respectively. There were no significant differences in the time for, or difficulty of, endoscopy. We conclude that any of these drugs can be used satisfactorily at the doses and combinations tested to pre-medicate cats prior to general anesthesia for GD. [ABSTRACT FROM AUTHOR]

Objective: To compare the quality of recovery in horses emerging from general anesthesia with or without the assistance of a novel device (recovery-enhancing device [RED]) designed to minimize high-energy falls., Animals: 20 mixed-breed horses, between July 1, 2023, and January 24, 2024., Methods: A computer-controlled belay system designed to slow the acceleration of a horse during a fall was evaluated in this study. Horses were randomly assigned to 1 of 2 treatment groups: RED (belay, assisted) or FREE (unassisted). An inertia-measuring unit was fitted to all horses and data were live streamed and recorded onto a computer for further analysis. Recoveries were scored using the composite grading scale (CGS; 0 to 100) by 3 independent observers. Two additional unitless recovery scores (RS and RS'), based on accelerometry values (high accelerations, less desirable), were calculated for each recovery. All the recovery scores were compared between the 2 treatment groups., Results: Composite grading scale scores were 26 ± 10 and 46 ± 13 in the RED and FREE groups, respectively (P = .001). The RS was 120 ± 79 and 198 ± 34 for the RED and FREE treatment groups, respectively (P = .015). The RS' was 32 (7 to 50) and 46 (28 to 44) for the RED and FREE treatment groups, respectively (P = .038)., Clinical Relevance: The RED improves the recovery scores compared with unassisted recoveries. This device may lead to a potential reduction in the number and severity of injuries in horses and personnel involved during the recovery period.

Objective: To describe the acquisition and pitfalls of a 3-view transesophageal echocardiography (TEE) protocol in anesthetized, dorsally recumbent dogs., Animals: 8 beagles, 1 to 2 years old, 7.4 to 11.2 kg., Methods: Dogs were anesthetized, mechanically ventilated, and placed in dorsal recumbency. A TEE probe was advanced, and 3 views were performed: midesophageal 4-chamber and long axis (ME 4C and ME LAX) and caudal esophageal short axis (CE SAX) at the level of the papillary muscles. Probe insertion depth, flexion, omniplane angle, and image acquisition time were recorded. Two observers assessed 24 video clips each and identified anatomical structures., Results: The ME 4C and ME LAX were obtained at 35 (30 to 40) cm insertion depth, omniplane at 0° and 103° (90 to 116), respectively. Views were obtained in ≤30 seconds once the TEE was in the cervical esophagus. Left-sided structures were identified in all cases, whereas right-sided structures were not always simultaneously obtained in the ME 4C, requiring further probe manipulation. All structures were identified on ME LAX. CE SAX was obtained at 40 (35 to 45) cm, omniplane at 0°, and in 15 (10 to 90) seconds. A true SAX view (circular left ventricle at the level of papillary muscles) could not be obtained in all dogs., Clinical Relevance: A 3-view TEE protocol using core views as those described in humans may be applicable to dogs under general anesthesia and in dorsal recumbency. The CE SAX view at the level of the papillary muscles appears more difficult to obtain with consistency than midesophageal views.

Objective: To compare the variability in the duration of action of a single dose of rocuronium or cisatracurium, and duration of subsequent top-up doses in anesthetized dogs., Animals: Thirty dogs requiring ophthalmic surgery with neuromuscular block., Procedures: Neuromuscular function was monitored with train-of-four (TOF) and acceleromyography. Dogs received an initial dose of rocuronium 0.6 mg/kg, or cisatracurium 0.15 mg/kg IV, which produced complete neuromuscular block. Upon return of the first response (T1) of TOF, a third of the initial dose was repeated. The duration of the initial dose and its variability were compared between agents. Duration of subsequent top-up doses was assessed with mixed effect models. Spontaneous (from last return of T1) or neostigmine-enhanced (from administration to complete recovery) recovery times were measured for each agent., Results: Duration of action of the initial dose was [median (range)] 25 (10-60) min with rocuronium and 35 (15-45) min with cisatracurium (p = .231). The variability of rocuronium was 3.25 times larger than cisatracurium (p = .034). Duration of top-up doses did not vary for either agent. Spontaneous recovery was shorter for rocuronium [15 (10-20) min] than cisatracurium [25 (15-45) min] (p = .02). Neostigmine-enhanced recovery times were 5 (5-25) for rocuronium and 10 (5-10) for cisatracurium (p = .491)., Conclusions: Duration of action for a single dose is significantly more variable with rocuronium than cisatracurium. Time to spontaneous recovery was longer for cisatracurium, and cases of unexpectedly long recovery times were observed with both agents. Objective monitoring is recommended., (© 2023 American College of Veterinary Ophthalmologists.)

Objective: To test whether the use of low-dose epidural anesthesia (EA) in goats undergoing lower urinary tract surgery reduces the requirements of perioperative analgesics, contributes to intraoperative hypotension, and improves postoperative comfort during the first 24 hours after surgery., Animals: Retrospective analysis of 38 goats between January 2019 and July 2022., Procedures: Goats were divided into 2 groups (EA or no EA). Demographic characteristics, surgical procedure, time of anesthesia, and anesthetic agents used were compared between treatment groups. Outcome variables potentially related to the use of EA included dose of inhalational anesthetics, incidence of hypotension (mean arterial pressure < 60 mm Hg), intraoperative and postoperative administration of morphine, and time to first meal after surgery., Results: EA (n = 21) consisted of bupivacaine or ropivacaine 0.1% to 0.2% with an opioid. There were no differences between groups except for age (EA group was younger). Less inhalational anesthetic (P = .03) and less intraoperative morphine (P = .008) were used in the EA group. The incidence of hypotension was 52% for EA and 58% for no EA (P = .691). Administration of postoperative morphine was not different between groups (EA, 67%, and no EA, 53%; P = .686). Time to first meal was 7.5 hours (3 to 18 hours) for EA and 11 hours (2 to 24 hours) for no EA (P = .057)., Clinical Relevance: Low-dose EA reduced the use of intraoperative anesthetics/analgesics in goats undergoing lower urinary tract surgery without an increased incidence of hypotension. Postoperative morphine administration was not reduced.

Objective: To evaluate the duration and analgesic quality of bupivacaine mixed with dexmedetomidine (BUP-DEX) or bupivacaine liposome suspension (BLS) administered as a transverse abdominis plane (TAP) block, compared with a negative control (no TAP block; CTRL) in dogs., Animals: 26 mixed-breed shelter dogs undergoing elective ovariohysterectomy between January 28 and December 8, 2020., Procedures: Each dog was randomly assigned to receive either an ultrasound-guided TAP block with either BUP-DEX or BLS or to receive no TAP block at time 0 after induction of general anesthesia. Superficial and abdominal wall pain scores were evaluated before time 0 and at 4, 6, 12, 24, 48, 72, and 96 hours later. Additionally, sedation scores and time to return of various behaviors, such as eating or drinking, were compared., Results: The CTRL group had significantly greater pain scores than the BUP-DEX and BLS groups, but no differences were found between the BUP-DEX and BLS groups. Postoperatively, significantly more dogs needed rescue analgesia and the time to need it was shorter for the CTRL group, compared with the BUP-DEX or BLS groups. Additionally, the CTRL group had greater sedation scores than the other 2 groups. No significant differences were observed in any of the evaluated outcome variables such as eating or drinking., Clinical Relevance: A TAP block appeared to provide adequate postoperative analgesia for abdominal surgery in the dogs of the present study undergoing elective ovariohysterectomy. The BLS TAP block did not appear to provide any extra benefit beyond what BUP-DEX TAP block added under these specific conditions.

Objective: To compare the duration of bupivacaine liposome suspension in the dog with that of bupivacaine and dexmedetomidine following a perineural injection., Animals: 8 healthy Beagles., Procedures: The left sciatic nerve of each dog was randomly assigned to an ultrasound-guided perineural injection with either bupivacaine liposome suspension (BLS) or with 0.5% bupivacaine with dexmedetomidine (1 µg/mL) (BUP-DEX). The contralateral nerve was assigned to the alternate agent. The sensory, motor, and proprioceptive functions were evaluated before the injection (baseline) and at 4, 10, 24, 48, 72, and 96 hours., Results: The block in 1 limb in the BLS treatment appeared to have failed (data set excluded). The motor scores of 2 individuals could not be evaluated leaving 5 limbs to evaluate in the BLS treatment and 6 in the BUP-DEX. A total of 6 out of 7 limbs in the BLS achieved a complete sensory block. In 3 out of 5 treatments with BLS, motor block was only partial and in 2 not apparent at all. Proprioceptive block was partial in 5 out of 7 dogs in the BLS treatment. All functions were still completely obliterated at 10 hours in 6 cases in treatment BUP-DEX. All functions were restored in all cases by 96 and 24 hours after administration of BLS and BUP-DEX, respectively., Clinical Relevance: The blockade characteristics of bupivacaine liposome suspension were effective and long lasting. Motor and proprioceptive deficits may be inconsistent over time.

The present study describes the magnitude and spatial distribution of lung strain in healthy anesthetized, mechanically ventilated dogs with and without positive end-expiratory pressure (PEEP). Total lung strain (LS TOTAL ) has a dynamic (LS DYNAMIC ) and a static (LS STATIC ) component. Due to lung heterogeneity, global lung strain may not accurately represent regional total tissue lung strain (TS TOTAL ), which may also be described by a regional dynamic (TS DYNAMIC ) and static (TS STATIC ) component. Six healthy anesthetized beagles (12.4 ± 1.4 kg body weight) were placed in dorsal recumbency and ventilated with a tidal volume of 15 ml/kg, respiratory rate of 15 bpm, and zero end-expiratory pressure (ZEEP). Respiratory system mechanics and full thoracic end-expiratory and end-inspiratory CT scan images were obtained at ZEEP. Thereafter, a PEEP of 5 cmH 2 O was set and respiratory system mechanics measurements and end-expiratory and end-inspiratory images were repeated. Computed lung volumes from CT scans were used to evaluate the global LS TOTAL , LS DYNAMIC , and LS STATIC during PEEP. During ZEEP, LS STATIC was assumed zero; therefore, LS TOTAL was the same as LS DYNAMIC . Image segmentation was applied to CT images to obtain maps of regional TS TOTAL , TS DYNAMIC , and TS STATIC during PEEP, and TS DYNAMIC during ZEEP. Compliance increased ( p = 0.013) and driving pressure decreased ( p = 0.043) during PEEP. PEEP increased the end-expiratory lung volume ( p < 0.001) and significantly reduced global LS DYNAMIC (33.4 ± 6.4% during ZEEP, 24.0 ± 4.6% during PEEP, p = 0.032). LS STATIC by PEEP was larger than the reduction in LS DYNAMIC ; therefore, LS TOTAL at PEEP was larger than LS DYNAMIC at ZEEP ( p = 0.005). There was marked topographic heterogeneity of regional strains. PEEP induced a significant reduction in TS DYNAMIC in all lung regions ( p < 0.05). Similar to global findings, PEEP-induced TS STATIC was larger than the reduction in TS DYNAMIC ; therefore, PEEP-induced TS TOTAL was larger than TS DYNAMIC at ZEEP. In conclusion, PEEP reduced both global and regional estimates of dynamic strain, but induced a large static strain. Given that lung injury has been mostly associated with tidal deformation, limiting dynamic strain may be an important clinical target in healthy and diseased lungs, but this requires further study., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Araos, Cruces, Martin-Flores, Donati, Gleed, Boullhesen-Williams, Perez, Staffieri, Retamal, Vidal Melo and Hurtado.)

Objective: Several factors affect the quality of recovery from general anesthesia in horses. These can increase the likelihood of injury. Body and limb position during recovery may correlate with successful standing. The objective of this study was to identify the prevalence of and the factors associated with successful standing at the first attempt in horses undergoing general anesthesia., Study Design: Retrospective study., Methods: Video of recovery and anesthetic records from 221 equine patients were reviewed by six veterinary students. Cases with poor video quality or incomplete anesthetic records were excluded. Demographic variables, type of procedure, perioperative drugs administered, assistance during recovery and body and limb positions during the first attempt to stand were recorded. Association between putative variables (including specific descriptors for body and limb position) and success for standing were analyzed using backward logistic regression; significance was set at 0.05. A decision tree for a successful attempt was created to predict the outcome of a recovery attempt based on these variables., Results: Extension of the carpal joints, head and neck alignment with the thoracic limbs, greater time in lateral recumbency, coordination during sternal recumbency, longer time to first attempt to stand and pelvic limb position were associated with successful standing at the first attempt. The association between extension of the carpal joints with wide base positioning of the pelvic limbs provided the best success rate for standing, whereas the association of flexed carpal joints and head and neck orientation different from the thoracic limbs resulted in a worse success rate., Conclusions and Clinical Relevance: Results suggest that certain limb and body positions displayed by horses during recovery may be associated with the likelihood of successful standing at the first attempt. These variables may be useful for assessing recovery quality in future research., (Copyright © 2021 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: To develop a scale to diagnose and assess the severity of postamputation pain (PAP) in dogs., Study Design: Single-center retrospective study., Animals: A total of 66 dogs that underwent thoracic or pelvic limb amputation and 139 dogs that underwent tibial plateau leveling osteotomy (TPLO) at a veterinary teaching hospital., Methods: An online survey regarding postoperative behavioral changes was sent to owners. Categorical, multiple-choice responses were entered into a univariable logistic regression model and tested for association with amputation using the Wald test. If p < 0.2, variables were forwarded to a multivariable logistic regression model for manual build. Model simplicity and predictive ability were optimized using the area under the receiver operating curve (AUROC) characteristic, and model calibration was assessed using the Hosmer-Lemeshow test. The selected model was converted to an integer scale (0-10), the Canine Postamputation Pain (CAMPPAIN) scale. Univariable logistic regression related each dog's calculated score to the probability of PAP., Results: Multivariable logistic regression identified four independent predictors of PAP (p < 0.05): 1) restlessness or difficulty sleeping, 2) episodes of panic or anxiety, 3) sudden vocalization, and 4) compulsive grooming of the residual limb. Score AUROC was 0.70 (95% confidence interval = 0.63-0.78) with good calibration (Hosmer-Lemeshow statistic p = 0.82). A score of 2 corresponded to a risk probability of 0.5. Taking a score ≥ 2 to indicate PAP, score specificity and sensitivity were 92.1% and 36.4%, respectively. When this score was used to diagnose PAP, prevalence was 36.4% (24/66) and 7.9% (11/139) in the amputation and TPLO groups, respectively., Conclusions and Clinical Relevance: Postamputation pain is characterized by specific postoperative behaviors and appears to affect approximately one-third of canine amputees. The CAMPPAIN scale generated from these data could facilitate diagnosis, treatment and further study of PAP but requires external validation., (Copyright © 2021 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objectives: 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., Methods: 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., Results: 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)., Conclusions and Relevance: 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.

Etorphine-azaperone is the most commonly used drug combination for chemical immobilisation of free-ranging white rhinoceroses, but causes several profound physiological disturbances, including muscle tremors. The addition of benzodiazepine sedatives, such as midazolam, has been proposed to reduce the muscular rigidity and tremors in immobilised rhinoceroses. Twenty-three free-ranging, sub-adult white rhinoceros bulls were darted and captured using a combination of etorphine plus either azaperone or midazolam. Skeletal muscle tremors were visually evaluated and scored by an experienced veterinarian, and tremor scores and distance run were compared between groups using the Wilcoxon rank sum test. No statistical differences were observed in tremor scores (p = 0.435) or distance run (p = 0.711) between the two groups, and no correlation between these variables was detected (r = -0.628; p = 0.807). Etorphine-midazolam was as effective as etorphine-azaperone at immobilising rhinoceroses, with animals running similar distances. Although the addition of midazolam to the etorphine did not reduce tremor scores compared to azaperone, it might have other beneficial immobilising effects in rhinoceroses, and further investigation is necessary to elucidate possible methods of reducing muscle tremoring during chemical immobilisation of rhinoceroses.

Aerial translocation of captured black rhinoceroses (Diceros bicornis) has been accomplished by suspending them by their feet. We expected this posture would compromise respiratory gas exchange more than would lateral recumbency. Because white rhinoceroses (Ceratotherium simum) immobilized with etorphine alone are hypermetabolic, with a high rate of carbon dioxide production (VCO2), we expected immobilized black rhinoceroses would also have a high VCO2. Twelve (nine male, three female; median age 8 yr old [range: 4-25]; median weight 1,137 kg [range: 804-1,234] body weight) wild black rhinoceroses were immobilized by aerial darting with etorphine and azaperone. The animals were in lateral recumbency or suspended by their feet from a crane for approximately 10 min before data were collected. Each rhinoceros received both treatments sequentially, in random order. Six were in lateral recumbency first and six were suspended first. All animals were substantially hypoxemic and hypercapnic in both postures. When suspended by the feet, mean arterial oxygen pressure (PaO2) was 42 mm Hg, 4 mm Hg greater than in lateral recumbency (P=0.030), and arterial carbon dioxide pressure (PaCO2) was 52 mm Hg, 3 mm Hg less than in lateral recumbency (P=0.016). Tidal volume and minute ventilation were similar between postures. The mean VCO2 was 2 mL/kg/min in both postures and was similar to, or marginally greater than, VCO2 predicted allometrically. Suspension by the feet for 10 min did not impair pulmonary function more than did lateral recumbency and apparently augmented gas exchange to a small degree relative to lateral recumbency. The biological importance in these animals of numerically small increments in PaO2 and decrements in PaCO2 with suspension by the feet is unknown. Black rhinoceroses immobilized with etorphine and azaperone were not as hypermetabolic as were white rhinoceroses immobilized with etorphine., (© Wildlife Disease Association 2021.)

Background: We evaluated the use of lumbosacral epidural anaesthesia (LEA) in dogs undergoing caesarean section over 10 years., Methods: Anaesthetic records were reviewed and divided into two treatment groups: LEA and control. Outcome variables identified a priori as potentially affected by LEA were compared between groups. Results are frequency or median (minimum-maximum)., Results: Ninety-five dogs received LEA and 87 did not. LEA consisted of 0.2 (0.1-0.3) ml/kg containing bupivacaine (n = 63), ropivacaine (n = 15), or lidocaine (n = 12) at concentrations ranging between 0.06% and 2%. Morphine, fentanyl, or buprenorphine were used as part of LEA. Groups were similar for demographic variables (all p > 0.06). Intravenous opioids were used more often in control than in LEA (p < 0.0005). Incidence of hypotension (MAP < 60 mm Hg) was LEA 68% and control 56% (p = 0.12). Duration of hypotension was longer in LEA (p = 0.03). Use of crystalloids and vasoactive drugs did not differ (all p > 0.1). Time from induction to operating room was 30 (8-75) min for control and 35 (18-65) min for LEA (p = 0.003)., Discussion: LEA during caesarean section in dogs was associated with lower rates of opioid administration and did not exacerbate the incidence of hypotension., (© 2021 British Veterinary Association.)

We evaluated the agreement between oscillometric and direct blood pressure monitors in anesthetized dogs and evaluated the ability of the oscillometric method to detect MAP <60 mmHg. Forty client-owned dogs, three months to 14 years old, 4.6-50.2 kg, under general anesthesia were studied. Systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures were measured directly via an arterial catheter and with an oscillometric cuff (Cardell Touch monitor). Paired values were compared with mixed effect models. Bias and limits of agreement (LOA) were calculated. The sensitivity and false negative rate to detect hypotension (invasive MAP <60 mmHg) using an oscillometric MAP <60 and < 70 mmHg were calculated. A receiver operating characteristics (ROC) curve was constructed and the area under the curve calculated. SAP and DAP differed between methods (both P < 0.001), but MAP did not (P = 0.5). Bland-Altman plots showed small biases but wide LOA for all variables. The sensitivity to detect hypotension was 40% with a false negative rate of 60% when using an oscillometric MAP <60 mmHg, and 68% and 32%, respectively, with a MAP <70 mmHg. The area under the ROC curve for MAP was 0.82. While the oscillometric MAP did not differ from invasive values, the device failed to recognize hypotensive events when 60 mmHg was used as the threshold to detect hypotension. Higher MAP values increased the ability to correctly recognize hypotension, but at the expense of a higher incidence of false positives., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Objective: To collect data about the current practice of recovering horses from general anesthesia and recovery personnel safety., Study Design: Online survey., Methods: An online questionnaire, including questions on general demographic data, recovery drugs, modality and characteristics of equine recovery and morbidity and mortality, was designed and distributed via e-mail to equine practitioners worldwide., Results: Practitioners from 22 countries completed 373 questionnaires; 53% of the participants were board-certified equine surgeons, and the remainder were board-certified anesthesiologists (18%), large animal residents (8%), general practitioners (7%), large animal interns (6%), anesthesia residents (4.5%) and veterinary technicians (1.6%). Respondents were employed by academia (58%) or private practice (42%). Of the respondents employed at a university, 93% had a board-certified anesthesiologist on staff compared with 7% of respondents employed at a private practice. Most of the respondents assist horses during recovery, with 23% assisting every recovery and 44% assisting recovery in the majority of cases. Reasons for choosing to assist horses during recovery were: orthopedic procedures (57%), neurological deficits (49%), bad health (47%), history of poor recovery (44%), foals (42%), draft breeds (30%), magnetic resonance imaging (17%) and computed tomography (16%). Unacceptable recoveries were reported by 77% of participants. Commonly reported complications during recovery with any method were: orthopedic injury (66%), myopathy (54%), skin abrasion (53%) and airway obstruction (37%). The incidences of unacceptable quality of recovery (p = 0.09) or personnel injury (p = 0.56) were not different between assisted and nonassisted recoveries; however, more equine fatalities were reported for assisted recoveries (p < 0.006). Practitioners in academia reported more unacceptable recoveries (p < 0.0007) and personnel injuries (p < 0.002) compared with those in private practice., Conclusions: The method of recovery differs among hospitals. Recovery personnel injuries associated with assisting horses during recovery are an important and previously unreported finding., (Copyright © 2021 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

This study used electrical impedance tomography (EIT) measurements of regional ventilation and perfusion to elucidate the reasons for severe gas exchange impairment reported in rhinoceroses during opioid-induced immobilization. EIT values were compared with standard monitoring parameters to establish a new monitoring tool for conservational immobilization and future treatment options. Six male white rhinoceroses were immobilized using etorphine, and EIT ventilation variables, venous admixture, and dead space were measured 30, 40, and 50 min after becoming recumbent in lateral position. Pulmonary perfusion mapping using impedance-enhanced EIT was performed at the end of the study period. The measured impedance (∆Z) by EIT was compared between pulmonary regions using mixed linear models. Measurements of regional ventilation and perfusion revealed a pronounced disproportional shift of ventilation and perfusion toward the nondependent lung. Overall, the dependent lung was minimally ventilated and perfused, but remained aerated with minimal detectable lung collapse. Perfusion was found primarily around the hilum of the nondependent lung and was minimal in the periphery of the nondependent and the entire dependent lung. These shifts can explain the high amount of venous admixture and physiological dead space found in this study. Breath holding redistributed ventilation toward dependent and ventral lung areas. The findings of this study reveal important pathophysiological insights into the changes in lung ventilation and perfusion during immobilization of white rhinoceroses. These novel insights might induce a search for better therapeutic options and is establishing EIT as a promising monitoring tool for large animals in the field. NEW & NOTEWORTHY Electrical impedance tomography measurements of regional ventilation and perfusion applied to etorphine-immobilized white rhinoceroses in lateral recumbency revealed a pronounced disproportional shift of the measured ventilation and perfusion toward the nondependent lung. The dependent lung was minimally ventilated and perfused, but still aerated. Perfusion was found primarily around the hilum of the nondependent lung. These shifts can explain the gas exchange impairments found in this study. Breath holding can redistribute ventilation.

Objective: To compare the duration of nociceptive and proprioceptive blockade from an experimental encapsulated lidocaine preparation with that of conventional lidocaine., Study Design: Prospective, blinded, randomly assigned, crossover study., Animals: A total of six adult Dorset ewes, American Society of Anesthesiologists physical status I or II, weighing 60.4 ± 18.0 kg (mean ± standard deviation)., Methods: Under general anesthesia and guided by electrolocation, the common peroneal nerve was blocked unilaterally with encapsulated lidocaine (0.1 mL kg -1 , 200 mg mL -1 ) or conventional lidocaine hydrochloride (0.1 mL kg -1 , 20 mg mL -1 ). Each sheep was administered both treatments with an interval of 2 weeks between treatments. Nociception and proprioception were scored (scales of 0-3) before anesthesia, at 0.5, 1, 2, 4, 8, 12, 16, 20 and 24 hours after completion of local anesthetic injection, and every 12 hours thereafter for 9 days. Nociceptive and proprioceptive blockade ended the first time each score reached '0'; maximum blockade duration was considered and recorded to be the time point immediately prior to this end point. Significance of differences between treatments for duration of blockade was tested with the Wilcoxon rank-sum test. Effects of time and treatment on nociceptive and proprioceptive blockade were evaluated with mixed-effect models. Significance was set at p < 0.05., Results: Compared with conventional lidocaine, nociceptive blockade lasted 88 hours longer with encapsulated lidocaine (p = 0.008), and proprioceptive blockade lasted 6 hours longer (p = 0.03). Significant effects of time (p < 0.0001), treatment (p = 0.0435) and treatment∗time (p < 0.0001) were observed for nociception. Significant effects of time (p < 0.0001) and treatment∗time (p = 0.0058) were observed for proprioception., Conclusion: Encapsulated lidocaine produced nociceptive blockade with a duration substantially longer than conventional lidocaine., Clinical Relevance: Sustained-release encapsulated lidocaine alleviates pain and may minimize systemic analgesic use., (Copyright © 2020 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: To evaluate arterial oxygenation during the first 4 postoperative hours in dogs administered different fractions of inspired oxygen (FiO 2 ) during general anesthesia with mechanical ventilation., Study Design: Prospective, randomized clinical trial., Animals: A total of 20 healthy female dogs, weighing >15 kg and body condition scores 3-7/9, admitted for ovariohysterectomy., Methods: Dogs were randomized to breathe an FiO 2 >0.9 or 0.4 during isoflurane anesthesia with intermittent positive pressure ventilation. The intraoperative PaO 2 :FiO 2 ratio was recorded during closure of the linea alba. Arterial blood was obtained 5, 60 and 240 minutes after extubation for measurement of PaO 2 and PaCO 2 (FiO 2  = 0.21). Demographic characteristics, duration of anesthesia, PaO 2 :FiO 2 ratio and anesthetic agents were compared between groups with Wilcoxon tests. The postoperative PaO 2 , PaCO 2 , rectal temperature, a visual sedation score and events of hypoxemia (PaO 2 < 80 mmHg) were compared between groups with mixed-effects models or generalized linear mixed models., Results: Groups were indistinguishable by demographic characteristics, duration of anesthesia, anesthetic agents administered and intraoperative PaO 2 :FiO 2 ratio (all p > 0.08). Postoperative PaO 2 , PaCO 2 , rectal temperature or sedation score were not different between groups (all p > 0.07). During the first 4 postoperative hours, hypoxemia occurred in three and seven dogs that breathed FiO 2 >0.9 or 0.4 during anesthesia, respectively (p = 0.04)., Conclusions and Clinical Relevance: The results identified no advantage to decreasing FiO 2 to 0.4 during anesthesia with mechanical ventilation with respect to postoperative oxygenation. Moreover, the incidence of hypoxemia in the first 4 hours after anesthesia was higher in these dogs than in dogs breathing FiO 2 >0.9., (Copyright © 2020 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Epidural anesthesia, often used during cesarean surgery, can exacerbate hypotension from general anesthesia and delay discharge due to motor block. Decreasing the local anesthetic dose might reduce those complications. Cases of dogs undergoing cesarean section that were anesthetized without epidural ( n = 29) (control) and dogs with low-dose epidural bupivacaine with fentanyl or buprenorphine ( n = 37) were reviewed. The incidence of hypotension was equal between groups. Intraoperative opioids were administered more to control (93%) than to treated dogs (18%; P < 0.0001). Epidural bupivacaine 0.0625-0.125% combined with an opioid reduced the use of intraoperative opioids and did not exacerbate arterial hypotension during cesarean section in anesthetized dogs., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

Objective: Thermal radiofrequency (TRF) of the saphenous nerve (a sensory nerve) combined with pulsed radiofrequency (PRF) of the sciatic nerve (a sensory and motor nerve) might relieve intractable stifle osteoarthritis (OA) pain in dogs. The objective was to determine if saphenous nerve TRF induces Wallerian degeneration and if sciatic nerve PRF induces degeneration or dysfunction., Study Design: Blinded, controlled, randomized, preclinical study., Animals: A group of six intact, female Beagle dogs aged 14-16 months., Methods: In each dog, one pelvic limb was assigned randomly to the control group and the other to the treatment group. Dogs were anesthetized and, using ultrasonography, radiofrequency electrodes were positioned adjacent to saphenous and sciatic nerves bilaterally; TRF and PRF were performed only in the treatment limb. Motor nerve conduction velocity (MNCV) was measured in both sciatic nerves 2 weeks later, and the dogs were euthanized. Hematoxylin and eosin-stained sections of saphenous and sciatic nerves were examined using light microscopy. Degeneration and inflammation were scored 0 (none) to 3 (severe). A one-tailed, paired Wilcoxon signed-rank test was used to test for differences in scores and MNCV between control and treatment nerves., Results: Degeneration and inflammation scores were higher in treatment saphenous nerves in 5/6 dogs [83%; 95% confidence interval (CI), 36%, 99%]; however, after Bonferroni correction only degeneration score was higher (p = 0.0313). Degeneration, inflammation or decreased MNCV were not observed in sciatic nerves (each outcome: 0/6 nerves, 0%; 95% CI, 0%, 48%). No dogs experienced postprocedural pain or neurological deficits., Conclusions and Clinical Relevance: The degeneration in TRF-treated saphenous nerves appears sufficient to impair transmission. Sciatic nerve PRF did not cause degeneration with attendant motor deficits, consistent with a proposed neuromodulatory mechanism. A clinical trial is needed to confirm the combined techniques produce analgesia without motor deficits in dogs with stifle OA., (Copyright © 2019 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

OBJECTIVE To evaluate potential associations between preanesthetic administration of acepromazine or dexmedetomidine and development of arterial hypotension or bradycardia in isoflurane-anesthetized dogs undergoing ovariohysterectomy. ANIMALS 341 dogs. PROCEDURES Medical records were searched to identify dogs that underwent ovariohysterectomy between January 2009 and December 2010 and received hydromorphone with acepromazine or dexmedetomidine as preanesthetic agents. Demographic data, sedative and anesthetic drugs, duration of anesthesia, average vaporizer setting, positive pressure ventilation, occurrence of hypotension (mean arterial pressure < 60 mm Hg) or bradycardia (> 50% reduction in heart rate, compared with the preanesthetic value), time to first occurrence and duration of hypotension, and treatment with dopamine or anticholinergic agents were recorded. Data were compared between dogs that received acepromazine and dexmedetomidine. Logistic regression was used to investigate associations between the treatments of interest (and other putative risk factors) and development of hypotension or bradycardia. RESULTS For dogs that received acepromazine, the odds of developing hypotension were 2.61 times those for dogs that received dexmedetomidine. Hypotension occurred earlier and lasted longer in dogs that received acepromazine, and this group was treated with dopamine more frequently than the group that received dexmedetomidine. Lower body weight was associated with increased odds of hypotension. Odds of developing bradycardia were greater for dogs sedated with dexmedetomidine (vs acepromazine) and for dogs that underwent anesthetic induction with propofol or a ketamine-benzodiazepine combination (vs thiopental). CONCLUSIONS AND CLINICAL RELEVANCE Anesthetic complications differed between isoflurane-anesthetized dogs undergoing ovariohysterectomy after premedication with acepromazine or dexmedetomidine in this study; future prospective investigations are warranted to investigate these effects in other, less homogenous populations of dogs.

Objective: To assess the ability to visually detect fade during train-of-four (TOF) or double burst stimulation (DBS) in anesthetized dogs recovering from nondepolarizing neuromuscular block., Study Design: Online anonymous survey., Population: Data from 112 participants., Methods: A web-based survey containing 12 videos of the response to ulnar nerve stimulation with TOF and 12 with DBS obtained at different levels of recovery from rocuronium-induced block was distributed to participants of the American College of Veterinary Anesthesia and Analgesia and the Academy of Veterinary Technicians in Anesthesia and Analgesia e-mail lists. Participants were asked to provide their highest training degree in anesthesiology, watch each video no more than twice, and determine whether fade was present. The probability to correctly recognize fade was calculated using binomial general linear models. General linear models and Tukey's tests were used to assess the effects of level of neuromuscular block, pattern of stimulation, and observers' training on the probability to detect fade., Results: The survey was completed by 53 diplomates, 29 licensed veterinary technicians, 24 residents and six doctors of veterinary medicine (DVMs). The probability to detect fade decreased as partial neuromuscular block became more shallow (p < 0.0001). A TOF or DBS ratio of 0.7 had a 50% chance of being detected. DBS was superior to TOF for detecting fade when the ratio was 0.3-0.69. TOF was superior to DBS when the ratio was 0.7-0.9 (p < 0.0001). There were no differences among groups of observers when assessing fade with TOF or DBS., Conclusions and Clinical Relevance: Detection of fade from observations of the response to TOF in dogs is unreliable. Advance training in anesthesiology or the use of DBS confers little to no advantage for this subjective test., (Copyright © 2019 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

The effects of etorphine on the pulmonary vascular system of white rhinoceros ( Ceratotherium simum) have not been described and could play a role in the severe hypoxemia that develops after immobilization with etorphine-based drug combinations. Characterization of these effects requires measurement of pulmonary vascular pressures and cardiac output (CO). To refine a technique for pulmonary arterial catheterization, five boma-habituated white rhinoceros (three females and two males weighing 1,012-1,572 kg) were immobilized by remote injection with etorphine plus azaperone followed by butorphanol. This afforded the opportunity to perform a pilot study and acquire preliminary measurements of pulmonary arterial pressure (PAP) and CO before and after supplemental etorphine given intravenously. Ultrasonographic guidance was used to insert a sheath introducer into a linguofacial branch of a jugular vein. A 160-cm-long pulmonary artery catheter with a balloon and thermistor was then passed through the introducer and positioned with its tip in the pulmonary artery. It was not long enough to permit wedging for measurement of pulmonary artery occlusion pressure. Mean PAP was 35 mm Hg (minimum, maximum 32, 47 mm Hg) and increased ( P = 0.031) by 83% (28, 106%) after supplemental etorphine. Thermodilution CO was 120 L/min (92, 145 L/min) and increased 27% (3, 43%) ( P = 0.031). Heart rate was 100 (88, 112) beats/min and increased 20% (4, 45%) ( P = 0.031), whereas arterial partial pressure of oxygen was 35 mm Hg (30, 94 mm Hg) and decreased 47% (20, 72%) ( P = 0.031). The cardiovascular observations could result from etorphine-induced generalized sympathetic outflow, as has been reported in horses. Further studies of etorphine in isolation are needed to test this suggestion and to discern how the changes in pulmonary vascular pressures and blood flow might relate to hypoxemia in etorphine-immobilized white rhinoceros.

Background: Locoregional anaesthetic techniques can facilitate certain surgeries being performed under standing procedural sedation. The second and third spinal cervical nerves (C2, C3) are part of the cervical plexus and provide sensory innervation to the peri-laryngeal structures in people; block of these nerves might permit laryngeal lateralisation surgery in horses., Objectives: To describe the anatomical basis for an ultrasound-guided cervical plexus block in horses. To compare this block with conventional local anaesthetic tissue infiltration in horses undergoing standing prosthetic laryngoplasty., Study Design: Cadaveric study followed by a double-blinded prospective clinical trial., Methods: A fresh equine cadaver was dissected to characterise the distribution of C2 and C3 to the perilaryngeal structures on the left side. A second cadaver was utilised to correlate ultrasound images with the previously identified structures; a tissue marker was injected to confirm the feasibility of an ultrasound-guided approach to the cervical plexus. In the clinical study, horses were assigned to two groups, CP (n = 17; cervical plexus block) and INF (n = 17; conventional tissue infiltration). Data collection and analyses included time to completion of surgical procedure, sedation time, surgical field conditions and surgeon's perception of block quality., Results: We confirmed that C2 and C3 provided innervation to the perilaryngeal structures. The nerve root of C2 was identified ultrasonographically located between the longus capitis and the cleidomastoideus muscles, caudal to the parotid gland. The CP group was deemed to provide better (P<0.0002) surgical conditions with no differences in the other variables measured., Main Limitations: Further studies with larger numbers of horses may be necessary to detect smaller differences in surgical procedure completion time based on the improved surgical filed conditions., Conclusions: For standing unilateral laryngeal surgery, a cervical plexus block is a viable alternative to tissue infiltration and it improves the surgical field conditions., (© 2018 EVJ Ltd.)

OBJECTIVE To evaluate the efficacy of each of 3 incremental doses of MK-467 for alleviation of dexmedetomidine-induced hemodynamic depression in isoflurane-anesthetized cats. ANIMALS 6 healthy adult domestic shorthair cats. PROCEDURES Each cat was anesthetized with isoflurane and received a target-controlled infusion of dexmedetomidine estimated to maintain the plasma dexmedetomidine concentration at 10 ng/mL throughout the experiment. Heart rate (HR) and direct arterial pressures were measured at baseline (isoflurane administration only), during dexmedetomidine infusion, and before and after IV administration of each of 3 serially increasing doses (15, 30, and 60 μg/kg) of MK-467. Cardiac index (CI) and systemic vascular resistance (SVR) were recorded at baseline, during dexmedetomidine infusion, and at the mean arterial pressure nadir after administration of the 30- and 60-μg/kg doses of MK-467. RESULTS Compared with baseline values, the dexmedetomidine infusion significantly decreased HR and increased arterial pressures. Each dose of MK-467 caused a significant decrease in arterial pressures and a significant, albeit clinically irrelevant, increase in HR (≤ 10%). Following administration of the 30- and 60-μg/kg doses of MK-467, all cats developed clinical hypotension (mean arterial pressure, < 60 mm Hg) even though CI and SVR returned to baseline values. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated administration of small doses of MK-467 to isoflurane-anesthetized cats receiving dexmedetomidine restored CI and SVR, but caused a substantial decrease in arterial pressures and only a marginal increase in HR. Therefore, caution should be used when MK-467 is administered to alleviate dexmedetomidine-induced hemodynamic depression in isoflurane-anesthetized cats.

Objective: To analyze practice habits associated with the use, reversal and monitoring of nondepolarizing neuromuscular blocking agents (NMBAs) in dogs by different groups of veterinarians., Study Design: Online anonymous survey to veterinarians., Population: Data from 390 answered surveys., Methods: A questionnaire was sent to e-mail list servers of the American College of Veterinary Anesthesia and Analgesia (ACVAA-list), Sociedad Española de Anestesia y Analgesia Veterinaria (SEEAV-list), Colégio Brasileiro de Anestesiologia Veterinária (Brazilian College of Veterinary Anesthesiology; CBAV-list) and American College of Veterinary Ophthalmologists (ACVO-list) to elicit information regarding use of NMBAs and reversal agents, monitoring techniques, criteria for redosing, reversing and assessing adequacy of recovery of neuromuscular function. Binomial logistic regression was used to test for association between responses and group of veterinarians in selected questions., Results: Veterinarians of the ACVO-list use NMBAs on a higher fraction of their caseload than other groups (all p < 0.0001). Subjective assessment (observation) of spontaneous movement, including spontaneous breathing, is the most common method for assessing neuromuscular function (43% of pooled responses); 18% of participants always reverse NMBAs, whereas 16% never reverse them. Restoration of neuromuscular function is assessed subjectively by 35% of respondents. Residual neuromuscular block is the most common concern regarding the use of NMBAs for all groups of veterinarians. Side effects of reversal agents (anticholinesterases) were of least concern for all groups., Conclusions and Clinical Relevance: While most veterinarians are concerned about residual neuromuscular block, relatively few steps are implemented to reduce the risks of this complication, such as routine use of quantitative neuromuscular monitoring or routine reversal of NMBAs. These results suggest a limitation in transferring information among groups of veterinarians, or in implementing techniques suggested by scientific research., (Copyright © 2018 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

OBJECTIVE To evaluate the effects of 2 fractions of inspired oxygen (Fio 2 s) during anesthesia on postanesthesia Pao 2 and other measures of oxygen exchange. ANIMALS 22 healthy adult sexually intact female dogs undergoing ovariohysterectomy by ventral midline celiotomy. PROCEDURES Dogs were randomly assigned to receive either oxygen (Fio 2 > 0.9 [100% oxygen]; n = 11; control group) or a mixture of nitrogen and oxygen (Fio 2 = 0.4; 11; 40% oxygen group) as the carrier gas for isoflurane while anesthetized. All dogs were allowed to breathe spontaneously while anesthetized. For each dog, the Pao 2 , Paco 2 , other indices of oxygenation, and extent of sedation were monitored at predetermined times during and for 1 hour after anesthesia. Measured variables were compared between the 2 treatment groups and over time within each treatment group. RESULTS None of the measured variables differed significantly between the control and 40% oxygen groups at any time during the postanesthesia period. Within each treatment group, the Paco 2 and extent of sedation decreased over time during the postanesthesia period. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that indices of oxygenation did not differ significantly between healthy dogs in which the Fio 2 was maintained at > 0.9 and those in which the Fio 2 was maintained at 0.4 while anesthetized for ovariohysterectomy. Thus, the addition of nitrogen to the carrier gas for an inhalant anesthetic conferred neither an advantage nor disadvantage in regard to oxygenation during the first hour of anesthesia recovery.

Background: Dynamic indicators such as pulse pressure and stroke volume variations can be measured to track changes in preload during hemorrhage, and evaluate fluid therapy. However, these dynamic indicators require mechanical ventilation, and might be affected by cardiac dysrhythmias and changes in vascular tone. Blood volume indicators may offer alternatives for assessing changes in volume status., Aims: The aims of this study were to measure changes in blood volume indicators and dynamic indicators during removal of blood in two stages and subsequent blood replacement in anesthetized, mechanically ventilated, neonatal pigs., Methods: In eight anesthetized, mechanically ventilated piglets (5-6 weeks old), cardiac index, stroke volume index, total end-diastolic volume, central blood volume, active circulating volume, pulse pressure variation, and stroke volume variation were measured during blood removal in two stages (15 mL kg -1 each stage) and blood replacement (30 mL kg -1 ). Values after each intervention were measured for each parameter., Results: All indicators differed from baseline after removal of 15 mL kg -1 of blood, except for stroke volume variation. Differences between both stages of hemorrhage were only observed for indexed stroke volume, total end-diastolic volume, central blood volume, and pulse pressure variation., Conclusion: Total end-diastolic volume and central blood volume changed during blood depletion and repletion, and differed between stages of hemorrhage. These indicators might be useful for assessing volume status instead of, or in addition to cardiac index and dynamic indicators., (© 2017 John Wiley & Sons Ltd.)