A-scan biometry, phacoemulsification, and foldable intraocular lens implantation in a young orangutan (Pongo pygmaeus).

Background: Cataracts are the major cause of visual impairment in animals which can be curable by surgical treatment. Phacoemulsification is the standard technique for cataract treatment that is applied to almost all species with a high success rate. Case Description: A 2-year-old intact female orangutan (Pongo pygmaeus) was presented for the study having bilateral opacity of the lenses, for 2 weeks. Ophthalmic examination revealed mature cataract OU. Ocular biometry measurements using A-scan ultrasonography for appropriate intraocular lens (IOL) refractive power calculation were carried out. Electroretinography was applied to ensure retinal function is intact. The orangutan underwent phacoemulsification OU and +24 diopter IOL implantation OS to restore vision. IOL implantation was not carried out OD because of a posterior capsular tear. Retinoscopy after 3 weeks postoperatively revealed +2.0 diopters OS. The outcome of the cataract surgery was successful during 3 years follow-up. The orangutan lived with other orangutans and was alert with normal behavior such as catching food, climbing trees, and swinging hand over hand from one branch to another. Conclusion: Cataract surgery with phacoemulsification OU and adjusted IOL implantation OD was successful with few complications in this orangutan. Vision was restored with normal behavior, even though an adjusted IOL was inserted in only one eye.

Influence of changing lateral recumbency and mode of ventilation on the alveolar-arterial oxygen tension gradient and selected laboratory analytes in adult isoflurane anesthetized horses.

This study investigated the influence of changing recumbency and mode of ventilation over repeated anesthesias on the alveolar to arterial oxygen tension gradient (PA-aO2) and laboratory analytes in eight horses during a year-long imaging study. Anesthesia was induced with xylazine, diazepam or guaifenesin, and ketamine and maintained with isoflurane. Horses were positioned in right or left lateral recumbency for computed tomography. Ventilation was controlled during 47% of the anesthetics. Blood was sampled from an arterial catheter prior to (30 ± 5 min from connection to anesthetic circuit), within 5 min of changing lateral recumbency, and prior to circuit disconnection (24 ± 6 min after second sample) for measurement of pH, partial pressure of arterial oxygen (PaO2) and partial pressure of arterial carbon dioxide, blood glucose and electrolytes. PA-aO2 was calculated. Data from five anesthetic episodes for each horse were summarized as mean ± standard error and analyzed using a mixed-model ANOVA. t tests were used for pairwise comparisons (P<0.05). PaO2 decreased after turning (198 vs. 347 mmHg), then increased to 291 mmHg prior to disconnection. Correspondingly, PA-aO2 was wider (252 vs.120 mmHg), and improved before disconnection (190 mmHg). Body temperature, ionized-Ca2+ and blood glucose were lower, and Na+ was higher at the last time point. In conclusion, turning anesthetized horses decreases PaO2 and results in a widening PA-aO2 suggesting a cautious approach in animals with pre-existing hypoxemia.

Comparison of surgical variables and pain in cats undergoing ovariohysterectomy, laparoscopic-assisted ovariohysterectomy, and laparoscopic ovariectomy.

Laparoscopy is an established modality in veterinary medicine. To date, laparoscopy in feline surgery is rarely reported. The objectives of this study were to compare surgical time, complications, and postoperative pain in a group of cats undergoing laparoscopic ovariectomy (LOVE), laparoscopic-assisted ovariohysterectomy (LAOVH), and ovariohysterectomy via celiotomy (COVH). Eighteen healthy cats were randomly assigned to undergo LOVE, LAOVH, or COVH. Severity of pain was monitored 1, 2, 3, and 4 hr after surgery. Surgical time was significantly longer for LAOVH (mean ± standard deviation [SD], 51.6 ± 7.7 min) compared to COVH (mean ± SD, 21.0 ± 7.1 min) and LOVE (mean ± SD, 34.2 ± 11.2 min). There were no major intraoperative complications, although minor complications were more common in both laparoscopic groups. Cats sterilized via laparoscopy (LOVE and LAOVH) were statistically less painful than cats spayed via celiotomy (COVH) 4 hr following surgery. Results suggested that LOVE in cats is safe, can be performed in a comparable amount of time as COVH, and may result in less postoperative discomfort.

Effects of continuous intravenous infusion of morphine and morphine-tramadol on the minimum alveolar concentration of sevoflurane and electroencephalographic entropy indices in dogs.

OBJECTIVE: To compare the effects of continuous rate infusions (CRIs) of intravenous (IV) morphine and morphine-tramadol on the minimum alveolar concentration (MAC) of sevoflurane, and on electroencephalographic entropy indices in dogs. DESIGN: Prospective study. ANIMALS: Eight young, healthy German shepherds, weighing 26.3 ± 3.1 kg (mean ± SD). METHODS: Anaesthesia was induced and maintained with sevoflurane. A standard tail-clamp technique was used for MAC determination. Within one anaesthetic period, MAC was first determined during sevoflurane anaesthesia alone (MACB ); then during morphine infusion (MACM ), (loading dose 0.5 mg kg(-1) IM; CRI, 0.2 mg kg(-1 ) hour(-1)) then finally during morphine-tramadol infusion (tramadol loading dose 1.5 mg kg(-1) IV; CRI, 2.6 mg kg(-1)  hour(-1) ) (MACMT ). At each change, periods of 45 minutes were allowed for equilibration. Stated entropy (SE), response entropy (RE), and RE-SE differences were measured five minutes prior to and during tail clamping. RESULTS: The MACB was 2.1 ± 0.3vol%. The morphine and morphine-tramadol infusions reduced MAC to 1.6 ± 0.3vol% and 1.3 ± 0.3vol%, respectively. MAC was decreased below baseline more during morphine-tramadol than during morphine alone (39 ± 9% versus 25 ± 6%, respectively; p = 0.003). All SE and RE and most RE-SE differences were increased significantly (p < 0.05) over pre-stimulation in all groups when the dogs responded purposefully to noxious stimulation. When no response to noxious stimulation occurred, the entropy indices did not change. CONCLUSION AND CLINICAL RELEVANCE: In dogs, combined morphine-tramadol CRI decreased sevoflurane MAC more than morphine CRI alone. Entropy indices changed during nociceptive responses in anaesthetized animals, suggesting that entropy measurements may be useful in determining anaesthetic depth in dogs.

Validation of the English version of the UNESP-Botucatu multidimensional composite pain scale for assessing postoperative pain in cats.

BACKGROUND: A scale validated in one language is not automatically valid in another language or culture. The purpose of this study was to validate the English version of the UNESP-Botucatu multidimensional composite pain scale (MCPS) to assess postoperative pain in cats. The English version was developed using translation, back-translation, and review by individuals with expertise in feline pain management. In sequence, validity and reliability tests were performed. RESULTS: Of the three domains identified by factor analysis, the internal consistency was excellent for 'pain expression' and 'psychomotor change' (0.86 and 0.87) but not for 'physiological variables' (0.28). Relevant changes in pain scores at clinically distinct time points (e.g., post-surgery, post-analgesic therapy), confirmed the construct validity and responsiveness (Wilcoxon test, p < 0.001). Favorable correlation with the IVAS scores (p < 0.001) and moderate to very good agreement between blinded observers and 'gold standard' evaluations, supported criterion validity. The cut-off point for rescue analgesia was > 7 (range 0-30 points) with 96.5% sensitivity and 99.5% specificity. CONCLUSIONS: The English version of the UNESP-Botucatu-MCPS is a valid, reliable and responsive instrument for assessing acute pain in cats undergoing ovariohysterectomy, when used by anesthesiologists or anesthesia technicians. The cut-off point for rescue analgesia provides an additional tool for guiding analgesic therapy.

Cardiovascular, respiratory, electrolyte and acid-base balance during continuous dexmedetomidine infusion in anesthetized dogs.

OBJECTIVE: To evaluate the cardiovascular, respiratory, electrolyte and acid-base effects of a continuous infusion of dexmedetomidine during propofol-isoflurane anesthesia following premedication with dexmedetomidine. STUDY DESIGN: Prospective experimental study. ANIMALS: Five adult male Walker Hound dogs 1-2 years of age averaging 25.4 ± 3.6 kg. METHODS: Dogs were sedated with dexmedetomidine 10 µg kg(-1) IM, 78 ± 2.3 minutes (mean ± SD) before general anesthesia. Anesthesia was induced with propofol (2.5 ± 0.5 mg kg(-1) ) IV and maintained with 1.5% isoflurane. Thirty minutes later dexmedetomidine 0.5 µg kg(-1) IV was administered over 5 minutes followed by an infusion of 0.5 µg kg(-1)  hour(-1) . Cardiac output (CO), heart rate (HR), ECG, direct blood pressure, body temperature, respiratory parameters, acid-base and arterial blood gases and electrolytes were measured 30 and 60 minutes after the infusion started. Data were analyzed via multiple linear regression modeling of individual variables over time, compared to anesthetized baseline values. Data are presented as mean ± SD. RESULTS: No statistical difference from baseline for any parameter was measured at any time point. Baseline CO, HR and mean arterial blood pressure (MAP) before infusion were 3.11 ± 0.9 L minute(-1) , 78 ± 18 beats minute(-1) and 96 ± 10 mmHg, respectively. During infusion CO, HR and MAP were 3.20 ± 0.83 L minute(-1) , 78 ± 14 beats minute(-1) and 89 ± 16 mmHg, respectively. No differences were found in respiratory rates, PaO2 , PaCO2 , pH, base excess, bicarbonate, sodium, potassium, chloride, calcium or lactate measurements before or during infusion. CONCLUSIONS AND CLINICAL RELEVANCE: Dexmedetomidine infusion using a loading dose of 0.5 µg kg(-1) IV followed by a constant rate infusion of 0.5 µg kg(-1)  hour(-1) does not cause any significant changes beyond those associated with an IM premedication dose of 10 µg kg(-1) , in propofol-isoflurane anesthetized dogs. IM dexmedetomidine given 108 ± 2 minutes before onset of infusion showed typical significant effects on cardiovascular parameters.

Effect of maropitant, a neurokinin-1 receptor antagonist, on the minimum alveolar concentration of sevoflurane during stimulation of the ovarian ligament in cats.

OBJECTIVE: Determine if maropitant decreases the minimum alveolar concentration (MAC) of sevoflurane during stimulation of the ovarian ligament in cats. STUDY DESIGN: Prospective study. ANIMALS: Fifteen, female cats weighing 2.5 ± 0.6 kg (mean ± SD). METHODS: Anesthesia was induced and maintained with sevoflurane. The right ovary was accessed via laparoscopy. A suture around the ovary and ovarian ligament was exteriorized through the abdominal wall for stimulation. A stimulus-response curve was created to identify the optimal force for MAC comparisons. In 10 cats, MAC was determined with only sevoflurane (baseline) then after 1 and 5 mg kg(-1) intravenous maropitant administration. The stimulation tension force used was 4.9 N. Repeated measures anova was used to compare the groups. MAC was defined as the average of the cross-over concentrations and reported MAC is adjusted to sea-level and depicted as mean ± SD. RESULTS: The stimulus-response curve was hyperbolic and plateaued at 4.3 ± 3 N. The optimal tension force chosen to compare MAC was 4.9 N. The baseline sevoflurane MAC was 2.96 ± 0.3%. Maropitant, 1 mg kg(-1) , decreased the MAC to 2.51 ± 0.3% (15%, p < 0.01). The higher maropitant dose of 5 mg kg(-1) did not change MAC further when compared to the low dose (2.46 ± 0.4%, p = 0.33). CONCLUSION AND CLINICAL RELEVANCE: The ovarian ligament stimulation model is suitable to determine MAC during visceral stimulation in cats. Maropitant decreased the anesthetic requirements during visceral ovarian and ovarian ligament stimulation in cats. Maropitant (1 mg kg(-1) ) decreases MAC by 15%; a higher dose had no additional effect.

Comparison of the analgesic efficacy of oral ABT-116 administration with that of transmucosal buprenorphine administration in dogs.

OBJECTIVE: To evaluate the analgesic efficacy of ABT-116, a transient receptor potential cation channel vanilloid subfamily V member 1 antagonist, and compare it with that of buprenorphine by measurement of mechanical and thermal nociceptive thresholds in dogs. ANIMALS: Six 7- to 8-month-old dogs (3 males and 3 females). PROCEDURES: In a crossover study design, all dogs received ABT-116 (30 mg/kg, PO) and buprenorphine (0.03 mg/kg, orotransmucosally), with each treatment separated by 1 week. Physiologic variables were recorded prior to and 1, 6, and 24 hours after drug administration. Thermal (thoracic) and mechanical (dorsolateral aspect of the radius [proximal] and dorsopalmar aspect of the forefoot [distal]) nociceptive thresholds were assessed prior to (baseline) and 15 minutes and 1, 2, 4, 6, 12, 18, and 24 hours after treatment. RESULTS: Buprenorphine administration resulted in higher overall thermal and proximal mechanical nociceptive thresholds, compared with ABT-116. Distal mechanical nociceptive thresholds after treatment were higher than baseline values for both treatments, but the magnitude of change was greater for buprenorphine at 1 hour after administration. Whereas HR and RR sporadically differed from baseline values after ABT-116 administration, rectal temperature increased from a baseline value of 39 ± 0.2°C (mean ± SD) to a peak of 40.6 ± 0.2°C at 6 hours. CONCLUSIONS AND CLINICAL RELEVANCE: In dogs without inflammation or nerve injury, PO administration of ABT-116 did not consistently result in an increase in nociceptive thresholds. However, clinically relevant increases in rectal temperature were identified after ABT-116 administration.

Evaluation of the sedative and cardiovascular effects of intramuscular administration of dexmedetomidine with and without concurrent atropine administration in dogs.

OBJECTIVE: To evaluate degree of sedation and cardiovascular, respiratory, acid-base excess, and electrolyte variables in response to IM administration of dexmedetomidine or dexmedetomidine with atropine. DESIGN: Randomized crossover study. Animals-5 healthy 1- to 2-year-old sexually intact male Treeing Walker Coonhounds. PROCEDURES: Dogs were instrumented with catheters placed in the dorsal pedal artery and lateral saphenous vein. All dogs received dexmedetomidine (10 µg/kg [4.5 µg/lb], IM) or dexmedetomidine with atropine (0.02 mg/kg [0.009 mg/lb], IM). Variables were measured at baseline (time 0) and 5, 15, 30, and 60 minutes after drug administration. RESULTS: In all dogs, lithium dilution cardiac output decreased from a mean ± SD baseline value of 5.07 ± 1.0 L/min to 2.1 ± 0.9 L/min. Cardiac output was not different between dexmedetomidine group dogs and dexmedetomidine-atropine group dogs. Mean arterial pressure increased from baseline in both groups but was significantly higher in dexmedetomidine-atropine group dogs, compared with dexmedetomidine group dogs. Heart rate in dexmedetomidine group dogs decreased from 110 ± 14.2 beats/min to 49.4 ± 10.4 beats/min by 15 minutes. No differences were seen in blood gas values, electrolyte concentration, or hemoglobin values over time or between groups. Arrhythmias were detected in dexmedetomidine-atropine group dogs and included atrioventricular block, ventricular premature contractions, and ventricular bigeminy. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of atropine at 0.02 mg/kg, IM, with dexmedetomidine at 10 µg/kg, IM, resulted in an increase in mean arterial blood pressure and heart rate; deleterious cardiac arrhythmias were also observed. Use of atropine with dexmedetomidine is not recommended in dogs.