Safety and efficacy of high‐dose fomepizole compared with ethanol as therapy for ethylene glycol intoxication in cats

Objective – To determine the safety and efficacy of high‐dose fomepizole compared with ethanol (EtOH) in cats with ethylene glycol (EG) toxicosis. Design – Prospective study. Setting – University veterinary research laboratory. Animals – Thirteen cats. Interventions – Two cats received injections of high‐dose fomepizole (Study 1). Three cats received lethal doses of EG and fomepizole treatment was initiated 1, 2, or 3 hours later (Study 2). Eight cats received a lethal dose of EG and were treated with fomepizole or EtOH (Study 3). Cats treated with fomepizole received 125 mg/kg IV initially, then 31.25 mg/kg at 12, 24, and 36 hours. Cats treated with EtOH received 5 mL of 20% EtOH/kg IV initially, then every 6 hours for 5 treatments, then every 8 hours for 4 treatments. Cats also received fluids and supportive therapy as needed. Measurements and Main Results – Clinical signs were monitored and serial blood analyses performed. Cats receiving fomepizole experienced mild sedation but no biochemical evidence of toxicity. Cats receiving fomepizole for EG intoxication survived if therapy was initiated within 3 hours of EG ingestion. One of the 6 developed acute renal failure (ARF) but survived. Only 1 of the 3 cats treated with EtOH 3 hours following EG ingestion survived; 2 developed ARF and were euthanized. Cats treated 4 hours following EG ingestion developed ARF, whether treated with EtOH or fomepizole. Conclusions – Fomepizole is safe when administered to cats in high doses, prevents EG‐induced fatal ARF when therapy is instituted within 3 hours of EG ingestion, and is more effective than treatment with EtOH.     

A Preliminary Comparison of Lidocaine and Xylazine as Epidural Analgesics in Ponies

Xylazine (0.35 mg/kg) or lidocaine (0.35 mg/kg) was injected into the epidural space of six ponies to compare their effectiveness as epidural analgesics. Each pony received both treatments at 1 week intervals with the order of treatments randomized. Xylazine produced analgesia of significantly longer duration (247 +/- 58 minutes) than that produced by an equal dose of lidocaine (135 +/- 22 minutes). Mild transient ataxia of no clinical significance developed in all ponies with both treatments. Spinal cords were removed from two ponies and examined histologically. No discernible pathologic changes were noted.     

Aerobic and anaerobic bacterial flora in the postpartum mare

Equine postpartum uterine bacterial contamination was studied. Thirteen mares were examined at foaling, at foal heat and again at the second estrus if not bred at foal heat (n=7). Twenty-three percent (3/13) of the mares showed no uterine bacterial contamination immediately post partum. This was increased to 77% (10/13) by foal heat and 100% (7/7) by the second post-partum estrus. Few anaerobic bacteria were isolated and were quickly eliminated. Anerobic bacteria do not appear to be a problem in the postpartum mare. The mare is capable of quickly eliminating postpartum uterine bacterial contamination. Endometrial etiology was shown to be a good screening test for uterine bacterial contamination in the postpartum mare.Bacterial endometritis has long been recognized as a major cause of infertility in the mare.⁵,⁸,¹² Bacterial culture techniques over the years have been improved as have the interpretation of such results. It is generally agreed upon that the isolation of bacteria by itself is insufficient evidence of disease.³,¹⁶,¹⁷,¹⁹,²⁵ Certain bacteria, Streptococcus zooepidemicus, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumonia, are known to be the major bacterial pathogens responsible for most of the cases of endometritis.⁷,¹⁸,²⁶ Isolation of bacteria in pure culture also is considered to be clinically significant; mixed cultures probably indicate insignificant contamination.²,²¹ The clinician also must consider the quantity of organisms isolated.¹,³,⁷,¹⁹,²⁶ Most pathogens occur in large numbers with heavy growth noted when cultured. In addition to kinds and quantity of bacteria isolated from the uterus, there also must be evidence of inflammation detected by physical examination of the genitalia, endometrial cytology and/or endometrial biopsy.⁴,⁹,¹⁴,¹⁵,²⁵,²⁷,²⁸The presence and significance of anaerobic bacteria in the mare's uterus has not been throughly addressed. It has been documented that aerobic and anaerobic bacteria play a significant role in postpartum uterine infections in the cow.²⁰Fusobacterium necrophorum and Corynebacterium pyogenes apparently have a synergistic effect to increase the severity of postpartum uterine infections in the cow.²⁰,²³ Anerobic bacteria, as well as mycoplasmas and viruses, have been suggested as possible causes of endometritis in the mare when evidence of inflammation is present but no aerobic bacteria are isolated.⁷,¹⁴,²¹,²⁷The purpose of this study was to document aerobic and anaerobic bacterial contamination of the uterus in the postpartum mare. Endometrial cytology was investigated to determine if there was a relationship between the presence of bacteria in the postpartum uterus and an inflammatory response.     

Circulatory, respiratory and behavioral responses in isoflurane anesthetized llamas

Objectives To evaluate the circulatory, respiratory and behavioral effects of isoflurane (ISO) anesthesia in llamas during mechanical ventilation and spontaneous breathing. Design Prospective randomised study. Animals Six adult, neutered male llamas (10 ± 1 years [mean ± SD], 179 ± 32 kg). Materials and methods Animals in which the minimum alveolar concentration (MAC) had been previously determined were anesthetized with ISO in oxygen. Inspired and end‐tidal (ET) ISO were sampled continuously. Arterial blood pH, respiratory and circulatory variables, and clinical signs of anesthesia were recorded at three doses (1.0, 1.5 and 2.0 times the individual animal's MAC; mean MAC value 1.13%) of ISO during spontaneous and controlled ventilation. A series of Latin squares was used to determine order of dose. Controlled ventilation (CV) (target PaCO₂ 38 ± 5 mm Hg [5.0 ± 0.6 kPa]) preceded spontaneous ventilation (SV) at each dose. Animals breathed spontaneously for approximately 10 minutes prior to data collection. Body temperature was maintained at 37 ± 0.6 °C. Circulatory and respiratory data were analysed with a mixed model, least squares analysis of variance, for repeated measures taken at equally spaced intervals. p < 0.05. Results Dose and mode of ventilation had significant influences on measured variables. For example, heart rate increased as dose increased; 67 ± 14 beats minute^?1 at 1.0 MAC‐CV versus 77 ± 6 beats minute^?1 at 2 MAC‐CV. Conversely, mean arterial pressure decreased with increasing dose; 82 ± 13 mm Hg at MAC‐CV versus 52 ± 15 mm Hg at 2 MAC‐CV. Arterial CO₂ increased with increasing dose during SV; 45 ± 5 mm Hg [6 ± 0.6 kPa] at MAC versus 53 ± 4 mmHg [7 ± 0.5 kPa] at 2 MAC. Reflex activity (e.g. palpebral reflex) and muscle tone (e.g. jaw tone) decreased while eyelid aperture increased with increasing anesthetic dose. Conclusions and Clinical Relevance The influence of ISO dose and mode of ventilation on circulatory and respiratory variables in llamas is qualitatively similar to that reported in other species. Changes in reflex activity and muscle tone may be used to guide appropriate anesthetic delivery in ISO‐induced llamas.     

Contact Mechanics of Simulated Meniscal Tears in Cadaveric Canine Stifles

Objective— To evaluate the biomechanical effects of 5 types of meniscal lesions on contact mechanics in the canine stifle.
Study Design— Experimental study.
Animals— Cadaveric canine stifles (n=12 pair).
Methods— Medial meniscal lesions (radial, vertical longitudinal, nonreducible bucket handle, flap, and complex tears) were simulated in cadaveric stifles. A contact map was recorded from each tear type and contact area (CA) and peak contact pressure (PCP) from each tear type were compared.
Results— A significant difference in PCP was detected between control and nonreducible bucket handle, flap, and complex tears. PCP increased by >45% in nonreducible bucket handle, flap, and complex meniscal tears when compared with control. No significant difference was found in PCP between control and radial and vertical longitudinal tears. No significant difference was found in CA between any of the meniscal conditions.
Conclusions— Nonreducible bucket handle, flap, and complex tears cause a significant increase in PCP. Radial and vertical longitudinal tears had a minimal impact on the contact pressures of the medial compartment of the stifle.
Clinical Relevance— Based on this ex vivo model, we support the clinical recommendation of debriding nonreducible bucket handle, flap, and complex tears because the injured portion of the meniscus no longer contributes significantly to the function of the meniscus. Radial and vertical longitudinal tears do not cause a change in contact mechanics allowing consideration of nonsurgical treatment and meniscal repair, respectively. Future experimental and clinical studies should aim to refine the treatment of specific meniscal injuries.