Retrospective case series to identify the most common conditions seen 'out-of-hours' by first-opinion equine veterinary practitioners

Effects of a 10% dimethyl sulfoxide solution on radiocarpal joint amikacin pharmacokinetics during intravenous regional limb perfusion in standing sedated horses

OBJECTIVE

To determine the effect of a 10% dimethyl sulfoxide (DMSO) solution on the peak concentration (CMAX ) of amikacin in the radiocarpal joint (RCJ) during intravenous regional limb perfusion (IVRLP) compared with 0.9% NaCl.

STUDY DESIGN

Randomized crossover study.

ANIMALS

Seven healthy adult horses.

METHODS

The horses underwent IVRLP with 2 g of amikacin sulfate diluted to 60 mL using a 10% DMSO or 0.9% NaCl solution. Synovial fluid was collected from the RCJ at 5, 10, 15, 20, 25, and 30 minutes after IVRLP. The wide rubber tourniquet placed on the antebrachium was removed after the 30 min sample. Amikacin concentrations were quantified by a fluorescence polarization immunoassay. The mean CMAX and time to peak concentration (TMAX ) of amikacin within the RCJ were determined. A one-sided paired t-test was used to determine the differences between treatments. The significance level was p < .05.

RESULTS

The mean ± SD CMAX in the DMSO group was 1361.8 ± 593 μg/mL and in the 0.9% NaCl group it was 860 ± 481.6 μg/mL (p = .058). Mean TMAX using the 10% DMSO solution was 23 and 18 min using the 0.9% NaCl perfusate (p = .161). No adverse effects were associated with use of the 10% DMSO solution.

CONCLUSION

Although there were higher mean peak synovial concentrations using the 10% DMSO solution no difference in synovial amikacin CMAX between perfusate type was detected (p = .058).

CLINICAL SIGNIFICANCE

Use of a 10% DMSO solution in conjunction with amikacin during IVRLP is a feasible technique and does not negatively affect the synovial amikacin levels achieved. Further research is warranted to determine other effects of using DMSO during IVRLP.

Retrospective evaluation of factors associated with emergency frequency and survival in equids presenting for emergency care (2019-2020): 3071 cases

OBJECTIVE

To determine factors associated with frequency and outcome of equid emergencies in private practice.

DESIGN

Retrospective study from February 2019 to January 2020.

SETTING

Private practice large animal hospital.

ANIMALS

A total of 3071 equids of various breeds and ages presenting for emergency care.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Variables included for analysis of daily emergency frequency included day of the week, month, and daily climate data. A Poisson regression model found the maximum temperature (P = 0.05), average barometric pressure (P = 0.005), and decreases in barometric pressure (P = 0.05) were associated with an increasing daily number of emergencies. Overall survival for all emergencies was 89% (2748/3071). Variables included for analysis of nonsurvival for emergencies included signalment, body system, clinical examination findings, laboratory data, and experience of the veterinarian. A logistic regression model for primary emergencies (nonreferral) found that increasing age, increasing heart rate, and decreased gastrointestinal sounds were associated with an increase in nonsurvival. Body system and experience of the veterinarian affected nonsurvival. A logistic regression model for all emergencies (primary and referral) found that absent gastrointestinal sounds and an increasing PCV were associated with increased nonsurvival.

CONCLUSIONS

The number of daily emergencies in this practice was affected by the month of the year and day of the week. Additionally, hotter days, increased barometric pressure, or drops in barometric pressure are likely to be associated with a higher emergency caseload. Nonsurvival of primary equid emergencies in private practice increases with age, higher heart rates, and decreased gastrointestinal sounds.

Epidemiology of Colic: Current Knowledge and Future Directions

Epidemiologic studies are essential for the generation of evidence-based, preventive health care strategies. This includes ways to minimize colic risk and assist informed decision making concerning diagnosis, treatment, and likely outcomes. It is important to consider that colic is not a simple "disease" but is a syndrome of abdominal pain that encompasses multiple different disease processes, and which is multifactorial in nature. This review focuses on prevention and diagnosis of colic, including specific forms of colic, communications with owners/carers concerning colic risk and management, and areas of future research.

Updates on Diagnosis and Management of Colic in the Field and Criteria for Referral

Gastrointestinal colic is the most common primary care equine emergency and affects nearly one of four horses per year. Colic is a significant welfare concern for equine patients and a financial and emotional burden for owners. The primary care practitioner is instrumental in identifying critical cases quickly and making appropriate management recommendations to improve patient outcomes.

Biofilm Production by Critical Antibiotic-Resistant Pathogens from an Equine Wound

As in human medicine, in veterinary medicine, chronic wounds are often related to polymicrobial infections and the presence of a biofilm, which compromises the effectiveness of therapeutic approaches. In this study, a Lusitano mare presented a 21-day-old chronic wound that was only being treated with an antiseptic. A swab sample was collected, and three isolates of Staphylococcus aureus and one of Pseudomonas aeruginosa were isolated. S. aureus did not show resistance to a panel of antibiotics. However, the P. aeruginosa isolate showed a resistance profile to carbapenems and fluoroquinolones, which may suggest a cross-resistance between antiseptic and antibiotics, given that no antibiotic therapy was applied to the wound or the mare in the previous year. Further experiments were conducted to assess the ability of the isolates to form biofilms, and to ascertain their susceptibility to gentamicin. The results demonstrated that the isolates produced biofilms. Gentamicin at the minimum inhibitory concentration (MIC) and 10× MIC caused biofilm removal between 59.3% and 85.7%, with the highest removal percentage being obtained for the P. aeruginosa isolate (at 10× MIC concentration). This study reveals that an equine wound was colonized by antibiotic resistant bacteria, and that all the wound colonizers could form biofilms, demonstrating the relevance of an adequate diagnosis and treatment when there is a suspicion of a biofilm-infected wound. It also highlights the possibility of resistance transmission between animals, animals and humans, or animals and the environment.

Management of Colic in the Field

Colic is one of the most frequent emergencies necessitating veterinary attention. Referral is not an option in many cases; therefore, the ability to diagnose and treat colic in an ambulatory setting is paramount. Portable imaging and point-of-care testing has improved the ability to identify lesions and assess the patient's status. In cases when field management is the only option, practitioners should be aware of the various treatment options available.

Owners' Knowledge and Approaches to Colic in Working Equids in Honduras

In Honduras, many families are reliant on working equids in their daily life. The aim of this study was to evaluate knowledge about, and approaches to colic used by owners of working equids in Choluteca, Honduras using a phenomenological approach. Semi-structured, verbal questionnaires were conducted with ninety-three owners from eleven different communities in the Choluteca region on equid horse owners' knowledge of colic and treatments. Additional context was gained through observations and verbal questionnaires with three veterinary practitioners and eight agricultural pharmacy (agrovet) store owners. Working equids were commonly used for firewood collection 31% (40/126), transportation 24% (30/126), and carrying crops 13% (17/126). Thirty-eight percent of owners (35/92) said they did not know what colic was, 27% (24/89) could not name any clinical signs, and 46% (42/92) could not name any causes. Most owners with previous experience of colic had treated it themselves 79% (53/67), typically using herbal remedies. Colic was a major concern for owners of working equids who had prior experience or knowledge of the condition. Knowledge and understanding of colic varied, and access to evidence-based treatments was very limited. The findings will be used to inform the development of educational resources on colic in working equids.

In vitro efficacy of a 0.2% polyhexamethylene biguanide-impregnated gauze dressing against pathogenic bacterial isolates found in horses

OBJECTIVE

To determine the ability of 0.2% polyhexamethylene biguanide (PHMB)-impregnated gauze to inhibit the growth of bacteria isolated from equine infected sites.

STUDY DESIGN

In vitro study.

METHODS

Nine bacterial isolates were obtained from cultures submitted from equine patients presenting with penetrating injuries of the hoof (n = 4), septic osteitis (n = 1), synovial sepsis (n = 1), wounds (n = 2), and incisional infection following laparotomy (n = 1). Two standardized strains were also included. A standard inoculum of each isolate was placed on 12 Muller-Hinton agar plates. Squares (2.5 cm × 2.5 cm) of 0.2% PHMB-impregnated (n = 6) and nonimpregnated control gauze (n = 6) were placed on inoculated agar plates. Bacterial growth under each gauze square was assessed after a 24-h incubation period and areas of inhibition were measured to a standardized scale, using image-processing software. Mean ± SD growth inhibition (%) using 0.2% PHMB-impregnated gauze was compared to the nonimpregnated gauze for each isolate using Student's t test (p < .05).

RESULTS

The 0.2% PMHB-impregnated gauze inhibited the growth of Staphylococcus spp. (n = 4) by 33%-83.1% and that of Escherichia coli spp. (n = 4) by 6.5%-37%. There was no inhibition of growth of Pseudomonas aeruginosa or either Enterococcus spp.

CONCLUSION

The 0.2% PHMB-impregnated dressing tested here inhibited the growth of staphylococcal and E. coli isolates, but the magnitude of inhibition varied between strains.

CLINICAL RELEVANCE

These results justify in vivo studies to evaluate the ability of the dressing to reduce the bacterial growth of common equine bacterial pathogens in clinical practice.

Indicators of 'critical' outcomes in 941 horses seen 'out-of-hours' for colic

BACKGROUND

This study aimed to describe the presentation and outcomes of horses with signs of colic (abdominal pain) seen 'out-of-hours' in equine practice.

METHODS

This was a retrospective study of horses seen 'out-of-hours' with colic by two equine veterinary practices between 2011 and 2013. Case outcomes were categorised as 'critical' or 'not critical'. A critical outcome was defined as requiring medical or surgical hospital treatment, or resulting in euthanasia or death. A non-critical outcome was defined as resolving with simple medical treatment. A hierarchical generalised linear model was used to identify 'red flag' parameters (aspects of signalment, history and presenting clinical signs) associated with critical outcomes.

RESULTS

Data were retrieved from 941 cases that presented with colic; 23.9 per cent (n=225/941) were critical. Variables significantly associated with the likelihood of a critical outcome in the final multivariable model were increased heart rate (P<0.001), age of the horse (P=0.013) and abnormal mucous membrane colour (P<0.001). Overall 18 per cent (n=168/941) of cases were euthanased.

CONCLUSIONS

This study highlights the mortality associated with colic. The 'red flag' parameters identified should be considered an essential component of the primary assessment of horses with colic.