Microscopy and genomic analysis of Mycoplasma parvum strain Indiana.

Mycoplasma parvum [Eperythrozoon parvum] is the second hemotrophic mycoplasma (hemoplasma) described in pigs. Unlike M. suis, its closest phylogenetic relative, M. parvum, is considered a non-pathogenic bacterium in this host species. Natural infection of a domestic, 6-month-old splenectomized pig with M. parvum strain Indiana is described herein. Light and scanning electron microscopy of the bacteria were performed in addition to whole genome sequencing, analysis, and comparison to the genome of M. suis strain Illinois. Neither clinical signs nor anemia were observed during the infection. Microscopy analyses revealed coccoid to rod- shaped organisms varying from 0.2 to 0.5 µm; they were observed individually or in short chains by both light and electron microscopy, however less than 30% of the red blood cells were infected at peak bacteremia. The single circular chromosome of M. parvum was only 564 395 bp, smaller than M. genitalium, previously considered the tiniest member of the Mollicutes. Its general genomic features were similar to others in this class and species circumscription was verified by phylogenomic analysis. A gene-by-gene comparison between M. suis and M. parvum revealed all protein coding sequences (CDS) with assigned functions were shared, including metabolic functions, transporters and putative virulence factors. However, the number of CDS in paralogous gene families was remarkably different with about half as many paralogs in M. parvum. The differences in paralogous genes may be implicated in the different pathogenic potential of these two species, however variable gene expression may also play a role. Both are areas of ongoing investigation.

Teaching veterinary anesthesia and surgery: the impact of instructor availability on anesthesia, operative, and recovery times in dogs undergoing ovariohysterectomy or castration.

Veterinary students learning to perform elective ovariohysterectomy (OVH) and castration procedures have traditionally been taught by a few instructors supervising many student groups simultaneously. This study, using a historical control group, explored the impacts of having a dedicated instructor with each student group for anesthetic induction and an entire surgical procedure. Our hypothesis was that preparation, surgical, and anesthesia times would be shorter and, consequently, post-operative recovery times would be shorter with a dedicated instructor compared to traditional methods. Anesthesia records of dogs undergoing elective surgery by third-year veterinary students were reviewed over 3 consecutive years. Traditional instruction was used in year 1 (Y1), and a dedicated instructor per student group was used in year 2 (Y2) and year 3 (Y3). Anesthesia time, surgical time, recovery time, and pre- and post-operative rectal temperature were analyzed, and a stepwise regression model was developed for factors influencing recovery time. Of 206 records reviewed (Y1, 33; Y2, 98; Y3, 75), there were 101 OVH procedures and 105 castration procedures. Preparation, surgery, and anesthesia times were longer in animals undergoing surgery in Y1, when the traditional instruction method was used. Recovery time was not influenced by instructor assignment. Using dedicated instructors to teach OVH and castration to third-year veterinary students decreased overall anesthesia time by 36 to 49 minutes for OVH and 29 to 32 minutes for castration. A teaching model of dedicated instructors requires excellent coordination between surgeons and anesthesiologists to ensure that a similar number of animals can undergo procedures in the time allotted for teaching.

Dexmedetomidine Sedation in Dogs: Impact on Electroencephalography, Behavior, Analgesia, and Antagonism with Atipamezole.

This study aimed to assess the impact of dexmedetomidine constant rate infusion (CRI) on key parameters in dogs. Six dogs received a 60 µg/kg/h dexmedetomidine infusion over 10 min, followed by three 15 min decremental CRIs (3, 2, and 1 µg/kg/h). A subsequent reversal phase employed 600 µg/kg/h atipamezole over 5 min. Continuous electroencephalogram (EEG) assessment, and cardiorespiratory and analgesia monitoring (every 3 min) were conducted, including analgesia evaluation through responses to electric stimulation. Dexmedetomidine induced profound sedation, evidenced by lateral recumbency and immobility. Patient State Index (PSI) decreased from awake (90.4 ± 4.3) to Phase 1 (50.9 ± 30.7), maintaining sedation (29.0 ± 18.1 to 33.1 ± 19.1 in Phases 2-4). Bradycardia (37.8 ± 3.5 bpm, lowest at Phase 3) and hypertension (133.7 ± 17.0 mmHg, highest at Phase 1) were observed, with minimal analgesia. Atipamezole promptly reversed sedation, restoring cognitive function (tail wagging behavior), and normalizing cardiovascular parameters. During atipamezole CRI, the EEG exhibited a transition from delta waves to alpha and low beta waves. This transition was observed alongside gradual increases in PSI and electromyographic activities. Additionally, spindle activities disappeared during this process. This study's results suggest potential clinical utility for EEG-guided dexmedetomidine sedation with reversal using atipamezole, warranting further investigation.

Ketamine-Propofol Coadministration for Induction and Infusion Maintenance in Anesthetized Dogs: Effects on Electroencephalography and Antinociception.

The effects of concurrent ketamine and propofol (ketofol) constant rate infusion (CRI) were examined in six dogs. The K:P ratio was 1:2, with an initial CRI of 0.25/0.5 mg/kg/min over ten minutes, followed by a 0.5 mg/kg ketamine bolus for induction. During induction, a comprehensive EEG frequency spectrum from delta to gamma was observed, accompanied by subanesthetic-dose ketofol-induced behavioral excitation, including nystagmus, tongue flicking, salivation and active muscle activity. The dogs were maintained on three 15 min decremental doses of ketofol CRI (0.8/1.6, 0.4/0.8 and 0.2/0.4 mg/kg/min). This phase featured a significant decrease in the Patient State Index, electromyographic activity and a shift to low beta waves (SEF95: 13-18 Hz). Additionally, profound antinociception to electric stimulation and a stable heart rate and blood pressure (MBP 81.5-110 mmHg) were observed, as well as a merging of ketamine and propofol EEG characteristics during maintenance. In the recovery phase, a return to beta and gamma EEG patterns and excitement behavior occurred, accompanied by a significant reduction in antinociception, highlighting features of low doses of ketofol. This study reveals biphasic EEG dynamic changes, associated behaviors and robust antinociception and cardiovascular function, suggesting the utility of ketofol as a total intravenous anesthetic combination in dogs.

Electroencephalographic and Cardiovascular Changes Associated with Propofol Constant Rate of Infusion Anesthesia in Young Healthy Dogs.

This study aimed to evaluate electroencephalography (EEG) and cardiovascular changes associated with propofol constant rate of infusion (CRI) anesthesia in dogs. Six dogs were each given propofol CRI to induce different anesthetic phases including induction (1 mg/kg/min for 10 min), and decremental maintenance doses of 2.4 mg per kg per min, 1.6 mg per kg per min, and 0.8 mg per kg per minute over 45 min. Processed EEG indices including patient state index (PSI), (burst) suppression ratio (SR), and spectral edge frequency (95%) were obtained continuously until the dogs recovered to sternal recumbency. The dogs were intubated and ventilated. Cardiovascular and EEG index values were compared between anesthetic phases. The PSI, SR, mean arterial blood pressure, and subjective anesthetic depth scores were highly correlated throughout anesthetic depth changes. The PSI decreased from 85.0 ± 17.3 at awake to 66.0 ± 29.0 at induction, and then sharply reduced to 19.7 ± 23.6 during maintenance and returned to 61.5 ± 19.2 at extubation. The SR increased from 15.4 ± 30.9% at induction to 70.9 ± 39.8% during maintenance and decreased to 3.4 ± 8.9% at extubation. We concluded that EEG indices can be used to aid in tracking ongoing brain state changes during propofol anesthesia in dogs.

Perioperative Brain Function Monitoring with Electroencephalography in Horses Anesthetized with Multimodal Balanced Anesthetic Protocol Subjected to Surgeries.

This study aimed to investigate the use of electroencephalography (EEG) for detecting brain activity changes perioperatively in anesthetized horses subjected to surgery. Twelve adult horses undergoing various surgeries were evaluated after premedication with xylazine and butorphanol, induction with ketamine, midazolam, and guaifenesin, and maintenance with isoflurane. The frontal EEG electrodes were placed after the horse was intubated and mechanically ventilated. The EEG data were collected continuously from Stage (S)1-transition from induction to isoflurane maintenance, S2-during surgery, S3-early recovery before xylazine sedation (0.2 mg kg IV), and S4-recovery after xylazine sedation. The Patient State Index (PSI), (Burst) Suppression Ratio (SR), and 95% Spectral Edge Frequency (SEF95) were compared across the stages. The PSI was lowest in S2 (20.8 ± 2.6) and increased to 30.0 ± 27.7 (p = 0.005) in S3. The SR increased from S1 (5.5 ± 10.7%) to S3 (32.7 ± 33.8%, p = 0.0001). The spectral power analysis showed that S3 had a significantly higher content of delta wave activity (0.1-4 Hz) in the EEG and lower relative power in the 3 Hz to 15 Hz range when compared to S1 and S2. A similar result was observed in S4, but the lower power was in a narrower range, from 3 Hz to 7 Hz, which indicate profound central nervous system depression potentiated by xylazine, despite the cessation of isoflurane anesthesia. We concluded that the use of EEG provides clinically relevant information about perioperative brain state changes of the isoflurane-anesthetized horse.

Evaluation of dexmedetomidine and ketamine in combination with opioids as injectable anesthesia for castration in dogs.

OBJECTIVE: To compare efficacy and cardiorespiratory effects of dexmedetomidine and ketamine in combination with butorphanol, hydromorphone, or buprenorphine (with or without reversal by atipamezole) in dogs undergoing castration. DESIGN: Prospective, randomized, split-plot, blinded study. ANIMALS: 30 healthy client-owned sexually intact male dogs. PROCEDURES: Dogs (n = 10 dogs/group) were assigned to receive dexmedetomidine (15 µg/kg [6.82 µg/lb]) and ketamine (3 mg/kg [1.36 mg/lb]) with butorphanol (0.2 mg/kg [0.09 mg/lb]; DKBut), the same dosages of dexmedetomidine and ketamine with hydromorphone (0.05 mg/kg [0.023 mg/lb]; DKH), or the same dosages of dexmedetomidine and ketamine with buprenorphine (40 µg/kg [18.18 µg/lb]; DKBup). All drugs were administered as a single IM injection for induction and maintenance of anesthesia for castration. At conclusion of the surgery, 5 dogs in each treatment group received atipamezole (150 µg/kg [68.18 µg/lb], IM), and the remainder received saline (0.9% NaCl) solution IM. Cardiorespiratory variables and quality of anesthesia were assessed. Supplemental isoflurane was administered to the dogs when anesthesia was considered inadequate during surgery. RESULTS: All drug combinations rapidly induced anesthesia. Dogs were intubated within 10 minutes after injection. Supplemental isoflurane was needed during surgery in 1, 3, and 4 dogs in the DKBup, DKBut, and DKH groups, respectively. Dogs that received atipamezole had a significantly shorter recovery time. Some dogs in each group had bradycardia and hypoxemia with hypertension. CONCLUSIONS AND CLINICAL RELEVANCE: DKBup was the most suitable injectable anesthetic combination used. Recovery was shortened by IM administration of atipamezole. There were minimal adverse effects in all groups.

Efficacy of oral transmucosal and intravenous administration of buprenorphine before surgery for postoperative analgesia in dogs undergoing ovariohysterectomy.

OBJECTIVE: To compare the efficacy of preoperative administration of buprenorphine (via oral transmucosal [OTM] and IV routes) for postoperative analgesia in dogs undergoing ovariohysterectomy. DESIGN: Prospective, randomized, blinded study. ANIMALS: 18 dogs undergoing routine ovariohysterectomy. PROCEDURES: Dogs were allocated to 3 groups (6 dogs/group) and were assigned to receive buprenorphine (20 µg/kg [9.09 µg/lb], IV; a low dose [20 µg/kg] via OTM administration [LOTM]; or a high dose [120 µg/kg [54.54 µg/lb] via OTM administration [HOTM]) immediately before anesthetic induction with propofol and maintenance with isoflurane for ovariohysterectomy. Postoperative pain was assessed by use of a dynamic interactive pain scale. Dogs were provided rescue analgesia when postoperative pain exceeded a predetermined threshold. Blood samples were collected, and liquid chromatography-electrospray ionization-tandem mass spectrometry was used to determine plasma concentrations of buprenorphine and its metabolites. Data were analyzed with an ANOVA. RESULTS: Body weight, surgical duration, propofol dose, isoflurane concentration, and cardiorespiratory variables did not differ significantly among treatment groups. Number of dogs requiring rescue analgesia did not differ significantly for the HOTM (1/6), IV (3/6), and LOTM (5/6) treatments. Similarly, mean ± SEM duration of analgesia did not differ significantly for the HOTM (20.3 ± 3.7 hours), IV (16.0 ± 3.8 hours), and LOTM (7.3 ± 3.3 hours) treatments. Plasma buprenorphine concentration was ≤ 0.60 ng/mL in 7 of 9 dogs requiring rescue analgesia. CONCLUSIONS AND CLINICAL RELEVANCE: Buprenorphine (HOTM) given immediately before anesthetic induction can be an alternative for postoperative pain management in dogs undergoing ovariohysterectomy.

Comparison of anesthetic and cardiorespiratory effects of tiletamine-zolazepam-detomidine-butorphanol, tiletamine-zolazepam-xylazine-butorphanol, and ketamine-detomidine-butorphanol in pigs.

OBJECTIVE: To evaluate and compare the anesthetic, analgesic, and cardiorespiratory effects of tiletamine-zolazepam-detomidine-butorphanol (TZDB), tiletamine-zolazepam-xylazine-butorphanol (TZXB), and ketamine-detomidine-butorphanol (KDB) in pigs and to assess anesthetic recovery duration and quality following administration of tolazoline as a reversal agent. ANIMALS: 11 healthy 2.5-month-old castrated male Landrace mixed-breed pigs. PROCEDURES: In a randomized, blinded crossover study design, pigs received the following anesthetic combinations, IM: TZDB (tiletamine-zolazepam [3 mg/kg {1.36 mg/lb}], detomidine [0.18 mg/kg {0.08 mg/lb}], and butorphanol [0.12 mg/kg {0.05 mg/lb}]); TZXB (tiletamine-zolazepam [4 mg/kg {1.8 mg/lb}], xylazine [4 mg/kg], and butorphanol [0.2 mg/kg {0.09 mg/lb}]); and KDB (ketamine [8 mg/kg {3.63 mg/lb}], detomidine [0.18 mg/kg], and butorphanol [0.3 mg/kg {0.14 mg/lb}]). A 7-day washout period was provided between treatments. At 45 minutes of anesthesia, pigs received tolazoline (2 mg/kg [0.9 mg/lb], IM; n = 6) treatment or control (5) treatment with saline (0.9% NaCl) solution. RESULTS: All anesthetic combinations induced anesthesia. Endotracheal intubation was completed within 5 minutes after anesthetic administration in all pigs, except in 2 pigs following administration of KDB. Durations (mean ± SD) of endotracheal intubation and lateral recumbency in pigs that did not receive tolazoline were 55.3 ± 4.8 minutes, 83.8 ± 15.8 minutes, and 28.2 ± 4.5 minutes and 112.4 ± 18.7 minutes, 117.2 ± 16.7 minutes, and 79.7 ± 6.0 minutes, respectively, for the TZDB, TZXB, and KDB anesthetic treatments. Tolazoline significantly shortened the duration of anesthetic recovery for all anesthetic treatments without affecting the recovery quality. CONCLUSIONS AND CLINICAL RELEVANCE: All 3 anesthetic combinations were suitable for providing anesthesia in pigs. Tolazoline administration shortened the duration of anesthetic recovery without affecting the quality of recovery.

Evaluation of Endotracheal Tube Cuff Pressure and the Use of Three Cuff Inflation Syringe Devices in Dogs.

Over-inflation of an endotracheal tube (ETT) cuff may lead to tracheal mucosal irritation, tracheal wall ischemia or necrosis, whereas under-inflation increases the risk of pulmonary aspiration as well as leaking anesthetic gas and polluting the environment. The objectives of this two-phase study were to (1) identify the incidence of improper ETT cuff inflation (both over- and under-inflation) using the minimum occlusive volume (MOV) technique coupled with a regular injectable syringe in the anesthetized dogs, and (2) evaluate the performance of two commercially available inflation syringe devices (Tru-Cuff and AG Cuffill®) with the regular injectable syringe in inflating the ETT cuff to a recommended safe cuff pressure range (20-30 cmH2O). Dogs undergoing general anesthesia at Purdue Veterinary Medicine Teaching Hospital were included. The ETT cuff pressure was assessed with an aneroid manometer after the syringe inflation. The results of the first objective showed that a total of 80 dogs enrolled and that 50 of these 80 dogs required ETT cuff inflation. Among the 50 dogs, only 14% had proper ETT cuff inflation; 76% of the ETT cuffs were over-inflated and 10% were under-inflated. Ninety dogs were enrolled for the second objective study and they were randomly and equally assigned to the three syringe device treatment groups. The results showed that 80% of the ETT cuffs were over-inflated in the regular injectable syringe treatment group, whereas only 6.7% and 3.3% ETT cuffs were over-inflated in the Tru-Cuff and AG Cuffill® syringe treatment groups, respectively. The AG Cuffill® syringe treatment group had a significantly (p < 0.05) higher percentage of properly inflated ETT cuffs (86.7%) compared to the other two groups (regular injectable syringe [3.3%]; Tru-Cuff syringe [50%]. We concluded that there was a high incidence of improper ETT cuff inflation when using MOV technique coupled with a regular injectable syringe. The use of an AG Cuffill® syringe significantly reduced improper ETT cuff inflation.

Effects of carprofen and morphine on the minimum alveolar concentration of isoflurane in dogs.

The minimum alveolar concentration (MAC) of isoflurane in dogs was determined following carprofen (2.2 mg/kg per os) alone, morphine (1 mg/kg intravenously) alone, carprofen and morphine, and no drug control in eight healthy adult dogs. Isoflurane MAC following administration of morphine alone (0.81%+/-0.18%) or carprofen and morphine (0.68%+/-0.31%) was significantly less than the control MAC (1.24%+/-0.15%). Isoflurane MAC after carprofen alone (1.13%+/-0.13%) was not significantly different from the control value. Results indicated that administration of morphine alone or in combination with carprofen significantly reduced the MAC of isoflurane in dogs. The isoflurane MAC reduction was additive between the effects of carprofen and morphine.

Effect of orally administered tramadol alone or with an intravenously administered opioid on minimum alveolar concentration of sevoflurane in cats.

OBJECTIVE-To compare the effect of oral administration of tramadol alone and with IV administration of butorphanol or hydromorphone on the minimum alveolar concentration (MAC) of sevoflurane in cats. DESIGN-Crossover study. ANIMALS-8 Healthy 3-year-old cats. PROCEDURES-Cats were anesthetized with sevoflurane in 100% oxygen. A standard tail clamp method was used to determine the MAC of sevoflurane following administration of tramadol (8.6 to 11.6 mg/kg [3.6 to 5.3 mg/lb], PO, 5 minutes before induction of anesthesia), butorphanol (0.4 mg/kg [0.18 mg/lb], IV, 30 minutes after induction), hydromorphone (0.1 mg/kg [0.04 mg/lb], IV, 30 minutes after induction), saline (0.9% NaCl) solution (0.05 mL/kg [0.023 mL/lb], IV, 30 minutes after induction), or tramadol with butorphanol or with hydromorphone (same doses and routes of administration). Naloxone (0.02 mg/kg [0.009 mg/lb], IV) was used to reverse the effects of treatments, and MACs were redetermined. RESULTS-Mean +/- SEM MACs for sevoflurane after administration of tramadol (1.48 +/- 0.20%), butorphanol (1.20 +/- 0.16%), hydromorphone (1.76 +/- 0.15%), tramadol and butorphanol (1.48 +/- 0.20%), and tramadol and hydromorphone (1.85 +/- 0.20%) were significantly less than those after administration of saline solution (2.45 +/- 0.22%). Naloxone reversed the reductions in MACs. CONCLUSIONS AND CLINICAL RELEVANCE-Administration of tramadol, butorphanol, or hydromorphone reduced the MAC of sevoflurane in cats, compared with that in cats treated with saline solution. The reductions detected were likely mediated by effects of the drugs on opioid receptors. An additional reduction in MAC was not detected when tramadol was administered with butorphanol or hydromorphone.

Effects of transdermal fentanyl solution application and subsequent naloxone hydrochloride administration on minimum alveolar concentration of isoflurane in dogs.

OBJECTIVE To assess the isoflurane-sparing effect of a transdermal formulation of fentanyl solution (TFS) and subsequent naloxone administration in dogs. DESIGN Experiment. ANIMALS 6 healthy mixed-breed dogs. PROCEDURES Minimum alveolar concentration (MAC) of isoflurane was determined in each dog with a tail clamp method (baseline). Two weeks later, dogs were treated with TFS (2.7 mg/kg [1.23 mg/lb]), and the MAC of isoflurane was determined 4 and 24 hours later. After the 4-hour MAC assessment, saline (0.9% NaCl) solution was immediately administered IV and MAC was reassessed. After the 24-hour MAC assessment, naloxone hydrochloride (0.02 mg/kg [0.01 mg/lb], IV) was immediately administered and MAC was reassessed. Heart rate, respiratory rate, arterial blood pressure, end-tidal partial pressure of CO2, and oxygen saturation as measured by pulse oximetry were recorded for each MAC assessment. RESULTS Mean ± SD MAC of isoflurane at 4 and 24 hours after TFS application was 45.4 ± 4.0% and 45.5 ± 4.5% lower than at baseline, respectively. Following naloxone administration, only a minimal reduction in MAC was identified (mean percentage decrease from baseline of 13.1 ± 2.2%, compared with 43.8 ± 5.6% for saline solution). Mean heart rate was significantly higher after naloxone administration (113.2 ± 22.2 beats/min) than after saline solution administration (76.7 ± 20.0 beats/min). No significant differences in other variables were identified among treatments. CONCLUSIONS AND CLINICAL RELEVANCE The isoflurane-sparing effects of TFS in healthy dogs were consistent and sustained between 4 and 24 hours after application, and these effects should be taken into consideration when anesthetizing or reanesthetizing TFS-treated dogs.

Optimized computed tomography protocol for assessment of dentition in alpacas.

OBJECTIVE To determine the optimal protocol for acquisition of CT images of the dentition in alpacas. ANIMALS 3 healthy adult male alpacas. PROCEDURES Each alpaca was anesthetized with an IM injection of a combination of ketamine, xylazine, and butorphanol and positioned in sternal recumbency on the CT couch with its legs folded in a natural cush position and its head positioned within the isocenter of the gantry of a 64-slice CT scanner. Images were acquired by means of 6 protocols (sequential and helical modes at slice thicknesses of 1.25, 2.5, and 5 mm). Five images (2 molar, 2 premolar, and mandibular incisor teeth) were selected from each protocol for evaluation by 3 veterinary radiologists. For each image, tooth root visibility and sharpness and image noise artifact were subjectively evaluated on a 3-point scoring system. RESULTS Slice thickness significantly affected tooth root visibility and tooth root sharpness but did not affect image noise artifact. Acquisition mode significantly affected tooth root visibility and tooth root sharpness as well as image noise artifact. Tooth root visibility and sharpness did not differ significantly between the helical and sequential images when the slice thickness was 1.25 mm. Image noise artifact was greater for helical images than sequential images but did not differ by slice thickness within either acquisition mode. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that for a 64-slice CT scanner, the optimal protocol for the acquisition of CT images of the dentition in alpacas was a sequential scan with a slice thickness of 1.25 mm.

Comparison of anesthetic and cardiorespiratory effects of tiletamine-zolazepam-butorphanol and tiletamine-zolazepam-butorphanol-medetomidine in dogs.

This study compared anesthetic and cardiorespiratory effects of tiletamine-zolazepam-butorphanol (TT), tiletamine-zolazepam-butorphanol-medetomidine (TTD), and tiletamine-zolazepam-butorphanol-medetomidine with atipamezole reversal 1 hour after TTD administration in dogs. All dogs received glycopyrrolate. All drug combinations effectively induced anesthesia within 5 minutes after IM injection. Duration of analgesia was 40 to 60 minutes. Recovery was smooth, but the overall quality of recovery was poorer in the TT group. Hypoxia occurred with some dogs in the TTD group at 5 minutes. TTD provided better analgesia with longer duration and better recovery quality compared with TT. Reversal of TTD with atipamezole was not effective in shortening recovery time.

A comparison of anesthetic and cardiorespiratory effects of tiletamine-zolazepam-butorphanol and tiletamine-zolazepam-butorphanol- medetomidine in cats.

Using a randomized crossover design, this study compared the anesthetic and cardiorespiratory effects of three intramuscular anesthetic combinations in seven 2-year-old cats: tiletamine-zolazepam (8 mg/kg) and butorphanol (0.2 mg/kg) (TT); tiletamine-zolazepam (3 mg/kg), butorphanol (0.15 mg/kg), and medetomidine (15 microg/kg) (TTD); or the TTD protocol plus atipamezole (75 microg/kg IM) given 20 minutes later to reverse medetomidine. Analgesia was assessed using algometry and needle pricking. All three combinations effectively induced anesthesia suitable for orotracheal intubation within 5 minutes after injection. Hemoglobin oxygen saturation was lower than 90% at least once in all three groups between 5 and 15 minutes after drug administration. Blood pressure and heart and respiratory rates were within normal ranges. Both TT and TTD appeared to be effective injectable anesthetic combinations. TTD provided significantly better analgesia with a longer duration than did TT. Atipamezole administration shortened the duration of analgesia and decreased blood pressure but did not shorten total recovery time.

Oxygenation in medetomidine-sedated dogs with and without 100% oxygen insufflation.

Oxygenation status was evaluated in medetomidine-sedated dogs breathing room air (M) or 100 percent oxygen (MO2). Medetomidine (40 microg/kg IV) administration resulted in peripheral vasoconstriction and decreased venous saturation as measured by an increased oxygen extraction ratio in peripheral tissues. Providing 100 percent oxygen insufflation via face mask reduced desaturation by increasing oxygen content but did not prevent vasoconstriction or reduce the oxygen extraction ratio in peripheral tissues. Atipamezole (200 microg/kg IV) reversed medetomidine-induced vasoconstriction and increased oxygen supply to tissues as indicated by a lower tissue oxygen extraction ratio. The authors conclude that 100 percent oxygen insufflation via face mask during medetomidine sedation (40 micrograms/kg [corrected] IV) benefits tissue oxygenation in healthy dogs.

Evaluation of three intravenous injectable anaesthesia protocols in healthy adult male alpacas.

Few studies have investigated the effects of intravenous injectable anaesthesia in alpacas. The objective of this study was to evaluate three intravenous injectable anaesthesia protocols in healthy adult alpacas exposed to noxious stimulation. A prospective randomised crossover study was done using six healthy adult male alpacas. Cardiopulmonary variables including heart rate, respiratory rate, mean arterial pressure, end-tidal pCO2 and haemoglobin oxygen saturation were collected immediately after and every two minutes following induction of each of three anaesthesia protocols in six male castrated alpacas. A hoof tester was used to apply consistent pressure every two minutes after induction and the response was recorded. Time from induction to muscle contraction and leg withdrawal were recorded, as well as time from induction to extubation, sternal recumbency and standing. There was no significant difference in duration of anaesthesia or cardiopulmonary variables among the three anaesthesia protocols. Total duration of anaesthesia was approximately 20 minutes for each protocol. Hypoxaemia and mild hypercarbia were common among all protocols. Induction and recovery scores were excellent.

Assessment of agreement among diplomates of the American College of Veterinary Anesthesia and Analgesia for scoring the recovery of horses from anesthesia by use of subjective grading scales and development of a system for evaluation of the recovery of horses from anesthesia by use of accelerometry.

OBJECTIVE To evaluate agreement among diplomates of the American College of Veterinary Anesthesia and Analgesia for scores determined by use of a simple descriptive scale (SDS) or a composite grading scale (CGS) for quality of recovery of horses from anesthesia and to investigate use of 3-axis accelerometry (3AA) for objective evaluation of recovery. ANIMALS 12 healthy adult horses. PROCEDURES Horses were fitted with a 3AA device and then were anesthetized. Eight diplomates evaluated recovery by use of an SDS, and 7 other diplomates evaluated recovery by use of a CGS. Agreement was tested with κ and AC1 statistics for the SDS and an ANOVA for the CGS. A library of mathematical models was used to map 3AA data against CGS scores. RESULTS Agreement among diplomates using the SDS was slight (κ = 0.19; AC1 = 0.22). The CGS scores differed significantly among diplomates. Best fit of 3AA data against CGS scores yielded the following equation: RS = 9.998 × SG0.633 × ∑UG0.174, where RS is a horse's recovery score determined with 3AA, SG is acceleration of the successful attempt to stand, and ∑UG is the sum of accelerations of unsuccessful attempts to stand. CONCLUSIONS AND CLINICAL RELEVANCE Subjective scoring of recovery of horses from anesthesia resulted in poor agreement among diplomates. Subjective scoring may lead to differences in conclusions about recovery quality; thus, there is a need for an objective scoring method. The 3AA system removed subjective bias in evaluations of recovery of horses and warrants further study.

Evaluation of surgical treatment for signs of acute abdominal pain in draft horses: 72 cases (1983-2002).

OBJECTIVE: To determine whether heavy (> or = 680 kg [> or = 1,500 lb]) draft horses undergoing surgical treatment for acute signs of abdominal pain were at a greater risk for anesthetic and postoperative complications and lower postoperative survival rates than light (< 680 kg) draft horses. DESIGN: Retrospective case series. ANIMALS: 72 draft horses. PROCEDURES: Medical records of draft horses that underwent exploratory celiotomy for signs of acute abdominal pain from October 1983 to December 2002 were reviewed. Medical records of draft horses in which a celiotomy was performed for correction of reproductive abnormalities were not included in the study. RESULTS: When compared with light draft horses, heavy draft horses had longer durations of anesthesia, more postoperative complications, and lower survival rates. Seventy-six percent of horses that recovered from anesthesia had postoperative complications. Postoperative complications associated with low survival rates included myopathy and neuropathy, ileus, diarrhea, and endotoxemia. All horses with postoperative myopathy and neuropathy died or were euthanized. The short-term survival rate for horses that recovered from anesthesia was 60%. Horses undergoing small intestinal surgery had a worse prognosis for short-term survival than those undergoing large intestinal surgery. The survival rate for horses for which long-term (> 1 year) follow-up information was available was 50%. CONCLUSIONS AND CLINICAL RELEVANCE: Draft horses weighing > 680 kg that underwent surgery because of acute signs of abdominal pain had longer durations of anesthesia, more postoperative complications, and higher mortality rates than draft horses weighing < 680 kg.