Plus-Hex CLINICAL the head well restrained to prevent injury to the animal or personnel ( Taylor et al ., 2005 ). Alternatively , where the option exists , the LAL is safer and more efficient for an unanaesthetised recumbent horse , as the straps can be more easily passed beneath the animal . Once in a standing position , this can be exchanged for the ASSD if available , which can then be applied over the LAL ( Pusterla & Madigan , 2006 ). The horse may need to be lowered again to facilitate the changing of the support frame between slings . Once the correct frame is in place , the horse can be attached to the frame ( Pusterla & Madigan 2006 ). The frame of the sling can be further stabilised by attaching it to supporting wall rings using long ropes to reduce excessive motion , particularly if the patient struggles while becoming familiar with the noise and feel of the sling .
Operation of the hoist
The sling is best operated by an electronic hoist for smoothness and swiftness ( Ishihara et al ., 2006 ). The hoist should not support more than 25 % of the horse ' s body weight for extended periods of time , to avoid complications associated with excessive pressure ( Furr , 2008 ). However , more recently , the use of a computer-integrated weight compensation system in combination with an ASSD showed that horses began to show complications ( such as avoidance behaviours and respiratory distress ) at > 20 % weight compensation ( Montgomery et al ., 2019 ), indicating that slings should not support more than 20 % of the horse ' s body weight . In the absence of an electronic weigh scale incorporated into the hoist , a spring-loaded scale could be incorporated into the hoist to estimate the percentage of body weight supported . Failing this , the hoist height must be subjectively estimated .
The hoist should be held at a height whereby the horse is weight bearing on all four limbs , while also being lightly supported by the sling . This means the horse is still able to move around in the sling but , if wishing to rest , the animal can relax into the sling and allow it to take more body weight for brief periods . Slings are most beneficial to horses that can partially support themselves , or those requiring prolonged periods of rest ( Furr , 2008 ). The patient should be encouraged to sit back into the sling and can also be facilitated to lie down by carefully lowering the hoist at the appropriate time . For horses that put their full weight into the sling , bales of shavings or hay can be used as a head rest . If the horse ' s temperament allows , the hoist can be used to elevate the horse further for short periods of time , to facilitate foot care or procedures such as bandage or cast changes , where the horse would need to lift its feet .
A common complication associated with the use of a sling on equine patients is that a horse can panic and struggle before becoming accustomed to the sling . It is advisable to have a competent handler at the horse ' s
head at all times during this period . Depending on the horse ' s temperament and restrictions , it can then be cross-tied or allowed loose in the sling in the stall .
Skin care
Shear pressure or friction occurs when a bone or underlying tissue moves in one direction and the skin moves in a different direction ( Davies , 2018 ). Thick padding , such as a saddle pad or numnah , placed along the dorsal midline and beneath the straps of the abdominal support section , can dramatically reduce skin ulceration caused by sustained shear pressure , which is unavoidable when maintaining a horse in sling long-term ( Figure 2 , previous page ). Extra padding should also be applied to the coarse material of the sling ' s chest panel , rear panel and leg straps , to minimise skin abrasions in areas of thin or sensitive skin ( Figure 1 , page 35 ). Ensure the choice of material is soft and breathable to discourage excessive sweating , such as natural sheepskin or cotton-fleece blankets ( Anders et al ., 2010 ). Natural sheep-fleece girth covers are useful for covering the straps of the sling . Fleecelined headcollars also help to minimise the occurrence of abrasions on the head when cross-tied . The patient ' s skin should always be kept clean and dry , in order to minimise skin maceration , which can , in turn , promote decubitus ulceration ( Anders et al ., 2010 ).
The rear panel and straps are at risk of becoming urine soaked , due to incontinence or an inability to posture correctly to urinate , particularly in mares . Prolonged urine contact with the skin alters the skin ' s pH , leading to contact dermatitis and , in turn , skin ulceration ( Anders et al ., 2010 ). Long-term urinary catheterisation of mares is not recommended , as it can lead to ascending urinary tract infections ( Hollis , 2008 ). Silver sulphadiazine or zinc-based barrier creams , talcum powder and incontinence pads can be used to reduce contact of urine with the skin ( Figure 4 ).
Figure 4 . Shows positioning of incontinence pads , and positioning of food and water within easy reach .
Volume 37 ( 4 ) • September 2022
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