When To Use Icing and Heating On Equine Injury
Icing and Heating: Acute Versus Chronic?
In a traditional sense, ice has been recommended for acute injuries, which may be any injury within the first 72 hours and up until the inflammatory response has resolved. Whereas, heat has been recommended for chronic injuries, which is the time period loosely noted to be 2-3 weeks post injury and onwards.
It is important to note that both may be utilised at the same time where the body requires simultaneous dilatation and constriction of blood vessels in order to promote lymphatic drainage and inflammatory exudate removal; which tends to be in the sub-acute phase (typically 1-2 weeks post injury).
Both ice and heat are inexpensive, easy to apply and may afford the patient short-term non-pharmacological analgesia. As such, the current treatment guidelines for acute injury recommend the application of ice immediately post-injury for 20 minutes, 3-4 times per day for the first 72 hours.
The rationale behind such recommendations is backed by evidence suggesting that cold therapy, inclusive of cryotherapy/ice/gel packs/ice packs/ice massage aid with the reduction of oedema, inflammation, pain, muscle spasm and secondary hypoxic injury; thereby aiding to restore function.
This is achieved by reducing the circulating levels of inflammatory markers such as neutrophils, which in turn generate free radicals heightening damage to the cell membrane; leading to tissue damage, pain and continued inflammation.
Whereas, heat which may be applied directly and superficially via hotpacks/hot water bottles/poultices/infrared heat lamps/immersion or deep which may be applied via shortwave diathermy/ultrasound. As such, heat may utilise conduction or convection to heat the underlying tissue to create a thermal effect.
Thus, muscle tissue temperature is elevated; thereby, increasing connective tissue extensibility as well as the resistance of muscle tissue to tearing, improving motor unit recruitment, and allowing for smoother muscle contraction. Furthermore, topical heat can reduce pain signals and increase proprioception all of which have been shown to decline in the presence of chronic injury/pain.
The methods of applying heat are quite different, which can impact upon both times required for treatment as well as the frequency at which each method should be implemented. The 2 most commonly utilised methods of heat application can be considered as heat packs and hydrotherapy.
Superficial heat involves applying dry heat or moist heat to the affected region to achieve a penetration depth of 2cm. Treatment can thus, range from 15 minutes to 1 hour depending upon the chronicity of the injury. Temperatures must be comfortable and tolerated by the patient.
Whereas, hydrotherapy, which involves submerging the patient in a warm body of water at temperatures between 34-36 degrees can be more individualised. Treatment time and water level should be adjusted according to the patient’s fitness and weight bearing status. Hydrotherapy is an active treatment technique; therefore, heat is generated by both movement and water temperature.
Methods of Ice Application
Similarly, the most commonly utilised methods of ice application may be one of the following three or a combination.
- Compressive cryotherapy (CC) combines pneumatic compression with ice to increase the surface area of contact. 30 minutes of CC is required to produce moderate to complete skin analgesia, lowering the target muscle’s metabolic functions.
- Whereas, topical ice involves the application of pliable cold/ice packs such as Equi-Ice packs to the affected body part. Topical ice can be safely implemented for up to 20 minutes to achieve a 4.7-8.2 degree reduction in tissue temperature.
- Lastly, cold water immersion is generally implemented for acute injuries/post-exercise/recovery. Affected body segments must be submerged in water at temperatures between 10 – 15 degrees for 15 minutes to produce desired physiological effects. However, this method may not be as well tolerated by animal patients.