Evaluation of digital cryotherapy using a commercially available sleeve style ice boot in healthy horses and horses receiving i.v. endotoxin

Continuous digital hypothermia for prevention and treatment of equine acute laminitis: A practical review

Laminitis is a severely debilitating and life-threatening condition that occurs as a consequence of different primary triggering factors. Continuous digital hypothermia (CDH) is recommended in horses at risk of, or diagnosed with, acute laminitis due to its several physiological and biochemical alterations that may be positive for the prevention and early treatment of the condition, representing a low risk of adverse effects. Modulation of the inflammatory response, profound vasoconstriction, and prevention of tissue damage are the most notable protective effects of cryotherapy on the lamellae. This practical review aims to summarize the published literature evaluating CDH efficacy in the prevention and early treatment of acute laminitis in horses, highlighting the most important clinical findings and discussing the best methods to provide cryotherapy. Nineteen publications evaluated different CDH methods, including the use of commercially available ice boots or fluid bags filled with iced water or crushed ice, as well as alternatives to immersion in ice, e.g., frozen gel packs and a perfused cuff prototype. Although some techniques were effective for cooling and maintaining the hooves below the optimal temperature of 10 °C, relevant limitations such as labor intensiveness, reliance on an ice source and price make its use impractical in some clinical situations. Twelve experimental studies assessed the efficacy of CDH on the prevention or early treatment of laminitis, finding multiple positive effects in terms of clinical improvement, immunological and inflammatory modulation, and histological protection. After the analysis of the literature, the clinical importance of CDH in different stages of laminitis remains clear. However, it also highlights the need for a safer, more user-friendly, and more effective method of cryotherapy that can be used both in a hospital and an ambulatory setting.

Efficacy of a commercial dry sleeve cryotherapy system for cooling the equine metacarpus

OBJECTIVE

To determine the ability of a commercial cryotherapy system (Game Ready Equine) to cool the metacarpal subcutaneous tissue and the superficial digital flexor tendon (SDFT) in horses.

STUDY DESIGN

Experimental study.

ANIMALS OR SAMPLE POPULATION

Six healthy adult horses.

METHODS

Thermocouples were implanted into the metacarpal subcutaneous tissues and the SDFT of six horses. Two treatments (cryotherapy or cryotherapy with 5-50 mmHg intermittent compression) were randomly assigned to forelimbs and performed for 20 minutes. Temperatures were compared to the target range of 10-19°C and between groups.

RESULTS

Only one limb in the cryotherapy/compression group reached the target range after cryotherapy. Temperatures did not differ between treatment groups at time 0. Lowest temperatures achieved in the subcutaneous tissue (p = .0043) and SDFT (p = .005) were 4.9 and 7.6°C lower when intermittent compression was applied. Similarly, applying compression induced a maximum change in temperature of approximately 7.0°C in the subcutaneous tissue (p = .014) and 10.2°C in the SDFT (p = .0001).

CONCLUSION

The cryotherapy system did not cool equine subcutaneous tissue or SDFT to the target temperature range, except in one limb. Combining cryotherapy with intermittent compression did result in lower temperatures and a greater change in temperature of the subcutaneous tissue and SDFT.

CLINICAL SIGNIFICANCE

When using this cryotherapy system, the addition of intermittent compression should be considered to achieve lower temperatures and potentially greater reduction in inflammation. Further studies are warranted to determine the effect of longer treatment times, higher compression settings, and the optimal temperature for benefits in normal and diseased equine tissues.

Cryotherapy Techniques: Best Protocols to Support the Foot in Health and Disease

Treatment of equine laminitis continues to be a challenge despite recent advancements in knowledge of the pathophysiology of laminitis. With more evidence supporting its use, distal limb hypothermia or cryotherapy has become a standard of care for both prevention of laminitis and treatment of the early stages of acute laminitis. Recent studies have demonstrated that cryotherapy reduces the severity of sepsis-related laminitis and hyperinsulinemic laminitis in experimental models and reduces the incidence of laminitis in clinical colitis cases. This article reviews the recent literature supporting the use of distal limb cryotherapy in horses.

Risk factors for laminitis and nonsurvival in acute colitis: Retrospective study of 85 hospitalized horses (2011-2019)

Background

Acute colitis is a serious cause of morbidity and death in horses. Recent studies have compared clinical features of coronavirus and salmonellosis, but no study has compared clinical features of enteric salmonellosis, coronavirus, and neorickettsiosis.

Hypothesis/Objectives

To identify risk factors for laminitis and nonsurvival to discharge in horses with enteric salmonellosis, coronavirus, or neorickettsiosis.

Animals

Eighty‐five horses hospitalized for acute colitis from 2011 to 2019.

Methods

Retrospective case series. Medical record review (2011‐2019) of adult (≥2 years) horses with colitis. Primary outcomes were laminitis and survival to discharge. Multivariable logistic regression was performed to assess association between variables and the development of laminitis. Stepwise Cox regression was performed to assess association between variables and survival.

Results

Seventeen of 85 (20%) horses developed laminitis during hospitalization. Neorickettsiosis cases (11/26, 42%) were more likely to develop laminitis than coronavirus (0/16, 0%) cases (odds ratio [OR] 24.48; 95% confidence interval [CI]: 1.33‐451.74, P = .03). There was no significant difference in laminitis between salmonellosis and neorickettsiosis cases (OR 0.27; 95% CI: 0.07‐1.07, P = .06). Admission heart rate (OR 1.08; 95% CI: 1.02‐1.15, P = .01), total solids (OR 0.17; 95% CI: 0.06‐0.54, P = .003), band neutrophils (OR 1248.47; 95% CI: 6.62‐235 540, P = .008), and bicarbonate concentration (OR 0.68; 95% CI: 0.5‐0.92, P = .01) were predictive of development of laminitis during hospitalization. Sixty‐three of 85 (74%) horses survived to discharge: 16/16 (100%) coronavirus cases, 17/26 (65%) neorickettsiosis cases, 14/20 (70%) salmonellosis cases, and 16/23 (70%) unknown cases. Packed cell volume (hazard ratio [HR] 1.17; 95% CI: 1.09‐1.26, P < .001), L‐lactate concentration (HR 1.33; 95% CI: 1.14‐1.55, P < .001), and development of laminitis (HR 7.07; 95% CI: 1.67‐29.95, P = .008) were retained in the final multivariable model for prediction of nonsurvival to discharge.

Conclusion and Clinical Importance

Nonsurvival and laminitis rates were high, likely related to the presence of neorickettsiosis in the region.