Search Results

Abstract

Case Description—A 24-year-old 732-kg (1,610-lb) pregnant Belgian draft horse mare developed neuropathy and signs of intractable pain following colic surgery.

Clinical Findings—Following recovery from colic surgery to treat compression of the small and large intestines because of a large fetus, the mare was noticed to have signs of femoral neuropathy involving the left hind limb. Within 36 hours after recovery, the mare developed signs of severe pain that were unresponsive to conventional treatment. No gastrointestinal tract or muscular abnormalities were found, and the discomfort was attributed to neuropathic pain.

Treatment and Outcome—The mare was treated with gabapentin (2.5 mg/kg [1.1 mg/lb], PO, q 12 h). Shortly after this treatment was initiated, the mare appeared comfortable and no longer had signs of pain. Treatment was continued for 6 days, during which the dosage was progressively decreased, and the mare was discharged. The mare subsequently delivered a healthy foal.

Clinical Relevance—Gabapentin appeared to be a safe, effective, and economical treatment for neuropathic pain in this horse.

Abstract

Objective—To determine morbidity and fatalities in cats with hepatic lipidosis that received propofol to facilitate placement of a feeding tube.

Study Design—Retrospective case series.

Animals—44 cats with presumed primary hepatic lipidosis anesthetized for placement of a feeding tube.

Procedures—Medical records from January 1995 through December 2004 were reviewed to identify cats that matched the inclusion criteria (histologic confirmation of hepatic lipidosis, anesthetized for placement of feeding tube, complete intensive care unit [ICU] records, and recorded outcome). Data extracted included age, body weight, sex, anesthetic drugs, drug dosages, type of feeding tube, duration of anesthesia, number of hours in ICU, administration of blood products, and survival until discharge from ICU.

Results—44 cats (21 females and 23 males) were included in the analysis. Age range was 3 to 15 years (median, 8 years), and body weight ranged from 1.8 to 9.0 kg (4.0 to 19.8 lb), with a median of 4.8 kg (10.6 lb). Twenty-seven cats were administered propofol. There was no significant association between the use of propofol or the dosage of propofol and any risk factor, need for blood products, number of hours in the ICU, or survival. There was no significant difference between cats that received propofol and cats that did not receive propofol with regard to interval until discharge from the ICU.

Conclusions and Clinical Relevance—The use of propofol did not increase morbidity or fatalities in cats with primary hepatic lipidosis. Thus, propofol can be used in these cats for placement of a feeding tube.

Abstract

OBJECTIVE To substantiate current AVMA guidelines for immersion euthanasia of goldfish (Carassius auratus) with tricaine methanesulfonate (TMS), determine whether immersion in propofol at 5 times its immersion anesthesia concentration for 30 minutes is sufficient for euthanasia of goldfish, and quantify the duration of myocardial contraction following immersion of goldfish in TMS and decapitation.

DESIGN Prospective clinical trial.

ANIMALS 36 healthy, adult goldfish.

PROCEDURES Goldfish were randomly assigned to be immersed in 1 of 6 test solution treatments (n = 6/treatment): TMS (500 mg/L) for 15 minutes followed by placement in anesthetic agent–free water (T15W), placement out of water (T15A), or decapitation (T15D); TMS (1,000 mg/L) for 15 minutes followed by placement in anesthetic agent–free water (T15XW); TMS (500 mg/L) for 30 minutes followed by placement in anesthetic agent–free water (T30W); or propofol (25 mg/L) for 30 minutes followed by placement in anesthetic agent–free water (P30W). Any fish that resumed operculation in group T15A was returned to anesthetic agent–free water. Times from onset of immersion to induction of anesthesia, cessation and resumption of operculation, and recovery (T15W, T15A, T15XW, T30W, P30W) or cessation of Doppler ultrasounds (T15D) were recorded.

RESULTS Overall, 5 of 6, 6 of 6, 6 of 6, 6 of 6, and 5 of 6 fish survived in the T15W, T15A, T15XW, T30W, and P30W groups, respectively. Median time to cessation of Doppler ultrasounds in group T15D was 77.5 minutes (range, 30 to 240 minutes).

CONCLUSIONS AND CLINICAL RELEVANCE Timed immersion in test solutions (TMS at 500 mg/L or 1,000 mg/L or propofol at 25 mg/L) resulted in death in only 7% (2/30) of immersed goldfish. Myocardial contractions continued for up to 4 hours in decapitated goldfish.

Abstract

Case Description—A healthy 6-year-old 28.5-kg (62.7-lb) spayed female Boxer undergoing surgical repair of a ruptured cranial cruciate ligament was inadvertently administered an overdose of morphine (1.3 mg/kg [0.59 mg/lb]) via subarachnoid injection.

Clinical Findings—50 minutes after administration of the overdose, mild multifocal myoclonic contractions became apparent at the level of the tail; the contractions migrated cranially and progressively increased in intensity and frequency during completion of the surgery.

Treatment and Outcome—The myoclonic contractions were refractory to treatment with midazolam, naloxone, phenobarbital, and pentobarbital; only atracurium (0.1 mg/kg [0.045 mg/lb], IV) was effective in controlling the movements. The dog developed hypertension, dysphoria, hyperthermia, and hypercapnia. The dog remained anesthetized and ventilated mechanically; treatments included continuous rate IV infusions of propofol (1 mg/kg/h [0.45 mg/lb/h]), diazepam (0.25 mg/kg/h [0.11 mg/lb/h]), atracurium (0.1 to 0.3 mg/kg/h [0.045 to 0.14 mg/lb/h]), and naloxone (0.02 mg/kg/h [0.009 mg/lb/h]). Twenty-two hours after the overdose, the myoclonus was no longer present, and the dog was able to ventilate without mechanical assistance. The dog remained sedated until 60 hours after the overdose, at which time its mentation improved, including recognition of caregivers and response to voice commands. No neurologic abnormalities were detectable at discharge (approx 68 hours after the overdose) or at a recheck evaluation 1 week later.

Clinical Relevance—Although intrathecal administration of an overdose of morphine can be associated with major and potentially fatal complications, it is possible that affected dogs can completely recover with immediate treatment and extensive supportive care.

Abstract

Objective—To determine whether repeated exposure to clinically relevant concentrations of tricaine methanesulfonate (MS-222) would alter retinal function or induce histologically detectable retinal lesions in koi carp (Cyprinus carpio).

Design—Prospective, controlled, experimental study.

Animals—18 healthy koi carp.

Procedures—2 fish were euthanized at the start of the study, and eyes were submitted for histologic evaluation as untreated controls. Anesthesia was induced in the remaining fish with 200 mg of MS-222/L and maintained with concentrations of 125 to 150 mg/L for a total exposure time of 20 minutes daily on 1 to 13 consecutive days. On days 1, 7, and 13, electroretinography of both eyes was performed in all fish remaining in the study, and 2 fish were euthanized immediately after each procedure for histologic evaluation of the eyes. Median b-wave amplitudes were compared among study days for right eyes and for left eyes via 1-way repeated-measures ANOVA with a Bonferroni correction for multiple comparisons.

Results—Median b-wave amplitudes on days 1, 7, and 13 were 17.7, 20.9, and 17.6 μV, respectively, for right eyes and 15.1, 16.9, and 14.3 μV, respectively, for left eyes. No significant differences in b-wave amplitudes were detected among study days. No histopathologic abnormalities were identified in the retinas of any fish treated with MS-222 or in control fish.

Conclusions and Clinical Relevance—Short-term exposure of koi carp to clinically relevant concentrations of MS-222 daily for up to 13 days was not associated with changes in retinal structure or function as measured in this study.

Abstract

Objective—To determine efficacy of propofol as an immersion agent to induce general anesthesia in koi (Cyprinus carpio).

Design—Prospective, crossover study.

Animals—10 adult koi (mean ± SD weight, 325 ± 81 g).

Procedures—Koi were exposed to each of 4 concentrations of propofol (1, 2.5, 5, and 10 mg/L) with a 1-week washout period between trials. In a subsequent trial, koi were anesthetized with propofol (5 mg/L) and anesthesia was maintained with propofol (3 mg/L) for 20 minutes. Response to a noxious stimulus was assessed by means of needle insertion into an epaxial muscle.

Results—At a propofol concentration of 1 mg/L, koi were sedated but never anesthetized. At propofol concentrations of 2.5, 5, and 10 mg/L, mean ± SD anesthetic induction times were 13.4 ± 3.3, 3.8 ± 1.1, and 2.3 ± 0.9 minutes, respectively; mean recovery times were 12.9 ± 8.3, 11.0 ± 6.3, and 18.1 ± 13.0 minutes; mean heart rates were 57 ± 25, 30 ± 14, and 22 ± 14 beats/min; mean opercular rates were 58 ± 18, 68 ± 15, and 48 ± 22 beats/min; and 1 of 10, 2 of 10, and 0 of 10 fish responded to needle insertion. All fish recovered satisfactorily. Following 20 minutes of anesthesia, 2 fish had recovery times > 4 hours and 1 fish died.

Conclusions and Clinical Relevance—Immersion in propofol at concentrations ≥ 2.5 mg/L induced general anesthesia in koi. Maintenance of anesthesia with propofol for 20 minutes was associated with prolonged recovery times in 2 of 9 and death in 1 of 9 koi.

Abstract

OBJECTIVE To compare complications between healthy horses undergoing general anesthesia for ophthalmic versus non-ophthalmic procedures and identify potential risk factors for the development of complications.

DESIGN Retrospective case series.

ANIMALS 502 horses (556 anesthetic procedures).

PROCEDURES Medical records from January 2012 through December 2014 were reviewed to identify horses undergoing general anesthesia. Signalment, body weight, drugs administered, patient positioning, procedure type (ophthalmic, orthopedic, soft tissue, or diagnostic imaging), specific procedure, procedure time, anesthesia time, recovery time, recovery quality, and postoperative complications were recorded.

RESULTS Patients underwent general anesthesia for ophthalmic (n = 106), orthopedic (246), soft tissue (84), diagnostic imaging (110), or combined (10) procedures. Mean procedure, anesthesia, and recovery times were significantly longer for patients undergoing ophthalmic versus non-ophthalmic procedures. Excluding diagnostic imaging procedures, there was a significant positive correlation between surgery time and recovery time. Within ophthalmic procedures, surgery time, anesthesia time, and recovery time were significantly greater for penetrating keratoplasty versus other ophthalmic procedures. There was a significantly higher rate of postoperative colic following penetrating keratoplasty, compared with all other ophthalmic procedures.

CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that in healthy horses, duration of general anesthesia should be minimized to decrease the risk of postanesthetic complications. Judicious use of orally administered fluconazole is recommended for horses undergoing general anesthesia. For horses undergoing a retrobulbar nerve block during general anesthesia, use of the lowest effective volume is suggested.

Abstract

OBJECTIVE To evaluate quality of recovery from general anesthesia in horses after induction with propofol and ketamine versus midazolam and ketamine.

DESIGN Prospective randomized crossover study.

ANIMALS 6 healthy adult horses.

PROCEDURES Horses were premedicated with xylazine (1.0 mg/kg [0.45 mg/lb], IV), and general anesthesia was induced with midazolam (0.1 mg/kg [0.045 mg/lb], IV) or propofol (0.5 mg/kg [0.23 mg/lb], IV), followed by ketamine (3.0 mg/kg [1.36 mg/lb], IV). Horses were endotracheally intubated, and anesthesia was maintained with isoflurane. After 60 minutes, horses were given romifidine (0.02 mg/kg [0.009 mg/lb], IV) and allowed to recover unassisted. Times to first movement, sternal recumbency, and standing and the number of attempts to stand were recorded. Plasma concentrations of propofol or midazolam were measured following induction and immediately before recovery. Recovery quality was scored by 3 graders with a recovery rubric and a visual analog scale.

RESULTS Number of attempts to stand was significantly lower when horses received propofol (median, 2; range, 1 to 3) than when they received midazolam (median, 7.5; range, 3 to 16). For both the recovery rubric and visual analog scale, recovery quality was significantly better when horses received propofol than when they received midazolam. Plasma drug concentration at recovery, as a percentage of the concentration at induction, was significantly lower when horses received propofol than when they received midazolam.

CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that for horses undergoing short (ie, 60 minutes) periods of general anesthesia, recovery quality may be better following induction with propofol and ketamine, compared with midazolam and ketamine.

Abstract

OBJECTIVE To compare physiologic and anesthetic effects of alfaxalone administered IV to yearling loggerhead sea turtles (Caretta caretta) at 3 different doses.

DESIGN Randomized crossover study.

ANIMALS 9 healthy yearling loggerhead sea turtles.

PROCEDURES Animals received each of 3 doses of alfaxalone (3 mg/kg [1.4 mg/lb], 5 mg/kg [2.3 mg/lb], or 10 mg/kg [4.5 mg/lb]) administered IV in randomly assigned order, with a minimum 7-day washout period between doses. Endotracheal intubation was attempted following anesthetic induction, and heart rate, sedation depth, cloacal temperature, and respirations were monitored. Times to first effect, induction, first voluntary muscle movement, first respiration, and recovery were recorded. Venous blood gas analysis was performed at 0 and 30 minutes. Assisted ventilation was performed if apnea persisted 30 minutes following induction.

RESULTS Median anesthetic induction time for all 3 doses was 2 minutes. Endotracheal intubation was accomplished in all turtles following induction. Heart rate significantly increased after the 3- and 5-mg/kg doses were administered. Median intervals from alfaxalone administration to first spontaneous respiration were 16, 22, and 54 minutes for the 3-, 5-, and 10-mg/kg doses, respectively, and median intervals to recovery were 28, 46, and 90 minutes, respectively. Assisted ventilation was required for 1 turtle after receiving the 5-mg/kg dose and for 5 turtles after receiving the 10-mg/kg dose. The 10-mg/kg dose resulted in respiratory acidosis and marked hypoxemia at 30 minutes.

CONCLUSIONS AND CLINICAL RELEVANCE IV alfaxalone administration to loggerhead sea turtles resulted in a rapid anesthetic induction and dose-dependent duration of sedation. Assisted ventilation is recommended if the 10 mg/kg dose is administered.

Abstract

Objective—To determine accuracy and precision of a point-of-care hemoglobinometer for measuring hemoglobin concentration and estimating PCV in horses.

Design—Prospective trial.

Animals—55 horses.

Procedure—Blood samples were obtained from 43 horses examined at a veterinary teaching hospital. Hemoglobin concentration was measured with the hemoglobinometer and by means of the standard cyanmethemoglobin method; PCV was measured by centrifugation. Blood samples were also obtained from 12 healthy horses, and PCV of aliquots of these samples was altered to approximately 5 to 80% by removing or adding plasma. Hemoglobin concentration and PCV were then measured.

Results—For samples from the clinic patients, hemoglobin concentrations obtained with the hemoglobinometer were less than concentrations obtained with the cyanmethemoglobin method; however, there was a linear relationship between concentrations obtained with the 2 methods. Breed, sex, body weight, and duration of sample storage did not significantly affect the difference between hemoglobin concentrations obtained with the 2 methods. There was a significant linear relationship between PCV and hemoglobinometer hemoglobin concentration (PCV = [2.83 X hemoglobin concentration] − 0.62). For samples from the healthy horses, a substantial negative bias was evident with the hemoglobinometer when hemoglobin concentration exceeded 16 g/dL.

Conclusions and Clinical Relevance—Results suggest that this hemoglobinometer is reasonably accurate and precise when used to measure hemoglobin concentration in blood samples from horses with a hemoglobin concentration < 16 g/dL. (J Am Vet Med Assoc 2003;223:78–83)