Advice for Owners on Administering First Aid

• Advice for owners regarding first aid should be given with caution. It is not always possible to assess the client’s ability from a telephone call. In a first aid emergency situation, it is important to advise the owner not to put themselves at risk. Human safety is a paramount consideration, and this should be made clear to the owner as a priority [5].

Some examples of relevant advice to give to clients are as follows:

• If a foreign body is present, it is acceptable to ask for the object not to be removed prior to the arrival of the vet, for example, a solar penetration [5]. Advice can be given on bandaging to allow the patient to stand without causing more damage to the area, such as taping something that is bigger than the object to the hoof, so that the object remains in place for the vet to see the direction of entry [6].
  
• If the patient is haemorrhaging, the owner should be asked to describe the nature of the bleeding, as it is important to find out if an artery has been damaged. If excessive bleeding is present, regardless of whether it is arterial or venous, the owner can be asked to apply pressure by applying a basic bandage or by holding a clean towel or jumper on the area [5]. If the bleeding seeps through the padding layer, further layers should be applied if this can be done safely.
  
• If a horse has colic and is rolling violently, the owner should be advised to put the horse in a safe area, for example, a stable with deep bedding, a small paddock or sand school and observe it until the vet arrives. The owner should be advised not to put themselves at risk under any circumstances.

First Aid Techniques

Identification and Treatment of Burns

Table 14.2 displays the most common types of burns seen in veterinary practice. Burns in horses are relatively uncommon and mostly occur during hot weather (radiation) or following a stable fire (thermal). The other burns described in Table 14.2 are less commonly seen.

Sunburn is commonly seen in horses with pink skin, especially around the muzzle or occasionally seen on limbs. First aid treatment would involve removing the horse from the source of the problem, so moving the horse to a stable. If a horse is ‘prone’ to sunburn, factor 50 sun cream should be applied if the horse is turned out during the day, and UV‐blocking rugs could be used [12]. Alternatively, only turning the horse out at night may be an effective solution.

Sunburn should not be confused with photosensitisation, which occurs when the UV rays of the sun react with photoproducts in the skin of certain horses. Primary photosensitisation can occur following ingestion of certain plants such as St John’s wort, clover and perennial ryegrass. The administration of medication such as phenothiazines, thiazides and sulfonamides may also make a horse more prone to developing primary photosensitisation. Secondary photosensitisation may occur due to underlying conditions such as liver disease, which will require further investigation and treatment [13]. See Chapter 13 for more information.

First aid for other burns involves removing the source of the problem and cooling the area with cool or lukewarm water for at least 20 minutes, being careful not to overcool the patient [14]. Cooling should be carried out immediately following the injury. The damaged skin should then be covered with a non‐adherent dressing or cling film and wound hydrogel. Creams should not be applied to burns in the first instance, and blisters should not be popped [15]. Foam dressings that are impregnated with honey or silver can be used to reduce the microbial population on the burn site and will be less likely to stick to the skin underneath it [16]. Analgesia is essential in most cases, and IV fluids may be required if the damage is extensive, but this will be assessed on arrival of the vet. Cooling is the most important first aid treatment for burns [5].

The seriousness of a burn depends on the depth and size of the area affected [11]:

1. First‐degree (superficial) burns: First‐degree burns affect only the epidermis. The burn site is red, painful, dry and there are no blisters present. An example would be mild sunburn. Long‐term tissue damage is rare.
   
2. Second‐degree (partial thickness) burns: Second‐degree burns involve the epidermis and part of the dermis layer of skin. The burn site appears red, blistered and may be swollen and painful.
   
3. Third‐degree (full thickness) burns: Third‐degree burns destroy the epidermis and dermis. There may also be damage to the underlying bones, muscles and tendons. When bones, muscles and/or tendons are also burned, this may be referred to as a fourth‐degree burn. The burn site appears white or charred. There is no feeling in the area as the nerve endings have been destroyed.

Thermal burns can be seen in foals that have had heat pads placed under them to keep them warm during surgery or if they are recumbent. Care should be taken to ensure that heat pads are not too hot and are not in direct contact with the skin. As well as thermal injuries, there is a possibility of tissue damage from friction burns, chemical burns or freeze damage (from ice therapy). Generally, the worse the burn, the larger the area it affects, and the greater the likelihood of shock, dehydration and infection.

Burns covering up to 50% or more of the body are usually fatal, although the depth of the burn also influences mortality. Wound infection is challenging to prevent because of the difficulty of maintaining a sterile wound environment. Long‐term care is required to prevent continued trauma because burn wounds are often pruritic, and self‐mutilation is common. Burns can cause disfigurement, which can affect athletic function. Therefore, the athletic use of the horse should be considered when deciding on an appropriate treatment programme.

Smoke inhalation can be seen alongside burns, especially if a horse has been in a stable fire. The patient should be removed from the smoke cloud during the initial assessment. Smoke inhalation can cause severe respiratory distress, and admission into an equine practice or hospital for intensive support and oxygen therapy may be required. It can take 24–36 hours to know the full extent of the damage for both smoke inhalation and burns, so close monitoring is required [14].

Poisons

Triage

Triage comes from the French word ‘trier’, which means to pick, choose or sort. In a veterinary sense, triage is defined as the process of rapidly classifying patients according to their clinical priority, allowing identification of those patients that might need urgent, lifesaving help and ensuring that this occurs immediately and before patients with less severe problems. [30]. In equine veterinary nursing, triage is crucial in efficiently managing horses’ diverse range of conditions and emergencies. For triage to occur successfully, information must be gathered from the patient’s history and initial clinical examination in a referral situation; this information may be gathered by the client care advisor (CCA) or RVN over the telephone prior to arrival. On arrival, an initial assessment can occur where the RVN quickly assesses the horse, noting vital signs, behaviour, and obvious signs of distress or injury. They gather information from owners or handlers regarding the horse’s history and the circumstances leading to the current situation.

Triage is normally associated with a colour scheme taken from human disaster response teams to quickly identify the agency of a patient’s medical needs. Using this system, triage can be broken into colour‐coded brackets, as shown in Table 14.4.

This table can help identify different triage categories, which helps prioritise cases from immediate to non‐urgent. This is a guide, and all practices will follow their own procedures. Generally, all patients in practice will be seen on arrival; however, if this is not possible, triage based on the type of case is the best way to proceed.

Often, the first opportunity for the RVN or CCA to ascertain whether an emergency is life‐threatening or not is through the initial telephone call made to the practice by the client. It is important to remember that the client may be distressed during this interaction. A calm, reassuring approach should be adopted during this exchange. Practice protocols for handling emergency telephone calls should be followed if available. If the emergency is identified as severe and life‐threatening, two options are available.

• A vet can be sent out to the patient’s location.
  
• The patient can be brought into the practice.

It is important to consider what is most appropriate for the patient and the client. The client may not have access to transport, the patient may not be used to being loaded or the patient may not be in a safe condition to transport. On the other hand, it may be quicker for the client to transport the patient to the practice, and if the patient is in an appropriate condition to travel, this may be the best option. More information on transporting critically ill horses can be found in Chapter 5.

Emergencies for which an examination by a vet should be advised without delay would include, but are not limited to, the following [30]:

• Colic
  
• Non‐weight bearing lameness
  
• Fracture
  
• Severe bleeding
  
• Respiratory distress
  
• Collapse or unconsciousness
  
• Sudden onset of severe neurological abnormalities
  
• Severe diarrhoea
  
• Extreme pain
  
• Ocular injury
  
• Acute laminitis
  
• Significant wounds
  
• Puncture wounds
  
• Dystocia
  
• Sick foal
  
• Dull, unusually quiet or sick donkey

In other situations, the RVN may need to question the client further to determine if the patient needs to be seen immediately or if an appointment can be made in the immediate future. Examples of this include, but are not limited to, the following [30]:

• Minor wounds
  
• Mild diarrhoea
  
• Mild lameness

It is advisable to take the name of the client and the patient and a contact telephone number at the start of the call. If first aid advice is required, this should be given according to existing practice protocols. The client’s safety should be considered during these calls. The administration of first aid measures should not be encouraged if there is a chance that this may result in injury to the client or the patient.

General rules for handling emergency telephone calls include the following [30]:

• When answering the phone call, the operator should state their name and the name of the practice.
  
• The operator should remain calm and polite at all times.
  
• It should be ascertained as quickly as possible whether this is a life‐threatening emergency.
  
• The timing and nature of the injury should be ascertained along with the details of any treatment given and the response of the animal to this.
  
• Details regarding the condition of the animal should be gathered, such as vital signs, degree of ataxia or ability to stand, any haemorrhage, discharge and estimation of pain levels.
  
• Give the client clear instructions and directions if they have decided to transport their horse to the practice.
  
• Ensure there is easy access at the practice to contact details for several transport companies and a horse ambulance service. The client may require these if they do not have their own transport.
  
• Advice regarding the safe transportation of the patient should be given.
  
• Obtain an estimated arrival time if the patient is coming to the practice.
  
• Obtain the client’s contact details, including a mobile phone number and repeat this information back to the client to ensure it is correct.
  
• Obtain detailed directions and a postcode for the yard if a vet is to attend. A code for What3words will also help the vet to find the yard.
  
• A financial quote should be given to the client for consideration.

When an emergency telephone call is taken, the RVN or CCA should inform the rest of the team if the patient is coming into the practice. This will allow for preparations to be made for the patient’s arrival.

A capsule history should also be obtained from the owners of emergency patients. This history focuses on the essential information that could alter the early management of the patient [30]. This history can be taken during the initial phone call or when the patient arrives at the practice. Important questions to ask regarding a capsule history are as follows [30]:

• What is the age and sex of the animal?
  
• If the animal is male, is he castrated?
  
• Is the animal on any medication? If so, when was the last dose given?
  
• Has the animal been diagnosed with any long‐term medical problems?
  
• What is the animal’s vaccination status?
  
• Does the animal have any known allergies?
  
• Has the animal had any access to known toxins?
  
• When was the last time the animal ate or drank?
  
• When was the last time the animal passed faeces and urinated? Was it normal?
  
• How long has the animal been showing signs of the current problem?
  
• Has this problem got better, worse or stayed the same since it was first noticed?
  
• Have there been changes to the way the animal is usually managed recently?

Preparing for the Admission of an Emergency Case

Careful preparation is the key to treating emergencies successfully [30]; as many things as possible should be prepared in advance. Paperwork, such as consent forms, should be completed as much as possible before the patient arrives. Additional members of staff should be organised as required. A designated area should be prepared before the patient’s arrival; this could be an examination room, radiography room, isolation unit, intensive care stable or foal unit, depending on the emergency being admitted. For all emergency cases, this area should be easily accessible from the car park or at least have access for a horsebox or trailer. This will prevent a debilitated patient from unnecessarily walking a long distance.

Immediate Care Upon Arrival, Stabilisation and Resuscitation

Any patient with a potentially life‐threatening condition should be taken to an appropriate area of the practice upon arrival, where a primary survey will be carried out [30]. The primary survey starts with an assessment as to whether cardiopulmonary cerebral resuscitation (CPCR) is required. This requirement is rare in equine emergencies, but a primary assessment should only take 30 seconds to carry out and may help to identify specific areas of concern. The mnemonic DRABC should be followed:

• D: Danger – before doing anything else, the first aider must assess the danger of the situation and check that it is safe to proceed
  
• R: Response – the first aider must test if the patient is responsive or not. If the patient is classified as unresponsive, the first aider should proceed through the ABC steps outlined below.
  
• A: Airway – does the patient have a patent airway?
  
• B: Breathing – is the patient making useful breathing efforts?
  
• C: Circulation – does the patient have evidence of spontaneous circulation (heartbeat and pulses)?

If CPCR is required, this should be instigated immediately, and a vet should be alerted to attend. The process of CPCR and the different roles required are covered in Chapter 10. If it has been established that CPCR is not required, a major body system assessment should be carried out. Within this assessment, the three main body systems are [30]:

• Cardiovascular
  
• Respiratory
  
• Neurological

To assess the cardiovascular and respiratory systems, clinical parameters should be assessed and quantified as described in Chapter 17. Neurological function can be evaluated by observing the patient’s gait and mentation [30]. Once the primary survey has been completed and treatment for any major body system abnormalities has been initiated, a secondary survey should be carried out. This involves a head‐to‐tail systematic examination of the patient. Areas that should be examined are as follows [30]:

• Nose
  
• Mouth
  
• Eyes
  
• Ears
  
• Limbs
  
• Hooves
  
• Thorax
  
• Abdomen
  
• External genitalia
  
• Tail

When dealing with any acute emergency, the RVN will play a significant role within the veterinary team. The RVN should be familiar with the equipment and medications that are likely to be required and have these ready and easily accessible. A proactive approach is required, and the RVN must think ahead to facilitate the developing situation [1]. This approach may include preparing an intensive care stable for the patient following the initial assessment. In this case, factors such as heating, comfort and the provision of appropriate food and fluid should be considered. Drug doses for medication prescribed by the case vet should be carefully worked out, prepared and administered as required. The RVN may be required to place an IV catheter and start the patient on IV fluids as directed by the vet. Oxygen may need to be administered, which should be set up quickly and efficiently, always considering patient and human safety. The RVN may also be required to assist in theatre in several roles, such as:

• Scrubbing in to assist with the surgical procedure
  
• Acting as a circulating nurse
  
• Monitoring the anaesthetic under the direction of a vet or assisting a vet with this process

As well as carrying out clinical procedures on the patient, the RVN may have a role in the organisation of the general area. This role may include managing people and equipment, keeping track of sharps and ensuring the health and safety of the patient and all staff members. The RVN may also take on the role of record‐keeping during emergency procedures. This will include noting clinical parameters, pain scoring, medication administered, timings for procedures, and if required, filling in the anaesthetic record. Accurate record‐keeping is essential for the case vet to use as a reference and for the practice to use in the case of litigation [1].

Critical Care Unit Design

Equine‐specific critical care units are becoming an essential part of equine hospitals. Critical care stables are now designed and built with specific characteristics to suit the needs of the patient and their condition. This overview of the principles informing design is intended to highlight some of the key decisions made about the planning, layout, equipment, staffing and operation of accommodation for critically ill patients.

Active Ventilation

Also known as mechanical ventilation, this includes air conditioning and hot air extractors. These units are mechanically powered and actively draw fresh air into the stable and then help to expel warm air from roof spaces. They work with and accelerate natural air flows, improving circulation faster than can naturally occur. To work efficiently, the stables and supporting rooms must be sealed from the outside environment.

Heating

If they are connected, there are often noticeable room temperature fluctuations between critical care stabling and the rest of the practice. If this can be minimised and attempts can be made to eliminate drafts, temperature variations between stables and treatment rooms will be easier to manage. A combination of constant ambient background heat and instant, concentrated heat sources (heat lamps) provides a selection of options according to the patient’s changing needs. Any heating supply that is within the stable must have an integrated circuit breaker as a safety measure to limit damage caused by an overcurrent or short circuit.

Heating facilities are commonly required for the following patients:

• Post‐operative colic patients
  
• Mares following a caesarean
  
• Sick foals
  
• Critical care patients, for example, atypical myopathy
  
• Chronically debilitated, underweight patients, e.g. dysautonomia (chronic grass sickness)

Lighting and Electrical Outlets

An important aspect of good critical care is the provision of adequate lighting so every area of the patient can be clearly examined. Installing several protected, waterproof and adjustable ceiling lights will help the veterinary care team examine the patient effectively. Adjustable lights allow for dimming when equipment like ultrasound machines are used in the stable. Night lights also assist the veterinary care team in making observations of inpatients at night, creating a calm atmosphere, especially around mares and foals, without disturbing them.

Mare and foal stables require many electrical outlets for the variety of infusion pumps and monitoring equipment that is needed to support a critically ill foal. These will need to be kept well out of reach of the mare and foal and encased in waterproof protective covers to prevent interference.

Features of lighting suitable in stables and adjoining passageways are as follows:

• Bright, dimmable lights without shadows
  
• Natural lighting with artificial options
  
• Skylights in covered passageways
  
• Lights that are waterproof to IP65 (Ingress Protection) rating for outdoor lighting. An IP65 rating means that the product is dust‐tight with protection against low‐pressure water jets from any direction.
  
• Waterproof light switches and sockets positioned outside stables, out of reach of the patient.

Health and safety should be considered at all times. Exposed electrical cables or surface‐mounted trunking in or near the stable should be avoided as this can be chewed by the horse. Dangling electrical extension leads, or cables should be avoided as these could present as trip hazards and lead to injury.

Fixtures and Fittings

Stainless‐steel fluid bag hangers are essential in critical care stables and must be securely fixed to the centre of the stable ceiling. A rope is fixed to the hanger via a swivelling ball bearing, goes through a pulley system, travels along the ceiling, through the wall and is fixed outside the stable, away from possible interference by the occupant. If installed correctly, this will support several 5‐l fluid bags and permit the raising and lowering of the whole system for bag changes (Figure 14.2).

Closed‐circuit television (CCTV) surveillance allows viewing from other areas of the practice and enables video capture if unusual clinical behaviour is observed. Regularly recording all monitored patient observations is essential, and these should be documented on critical care forms or on the practice’s software systems.

Breathing and Cardiovascular Function

Treatment and care of cardiovascular disease should be specific to the disease. Medical therapy can manage some conditions, with the aim to limit damage to cardiac muscle, control the fluid accumulation in the lungs, improve circulation and regulate the heart rate and rhythm. For the clinically unstable, giving intranasal oxygen can improve oxygenation and support cardiac function. Heart rate, pulse rate and respiratory rate should be monitored regularly (see Chapter 17). All patients suffering from cardiovascular disease should be encouraged to maintain a comfortable position that optimises breathing and oxygen delivery to tissues. This can be assisted by keeping weakened and recumbent patients, no matter what size, maintained in sternal recumbency. Maintaining a recumbent patient in sternal recumbency will also reduce the chances of hypostatic pneumonia developing [33]. Physiotherapy techniques can be used to promote circulation to the affected areas [33] (see Chapter 17). The goal is for the treatment to return heart and respiratory rates to normal and even if there is no cure, for the horse to have a good quality of life. These patients require intensive nursing and regular monitoring.

Parenteral Nutrition

For a short period of time, the sick patient can have its caloric needs met by IV crystalloid infusions with dextrose and by utilising its internal stores. If it remains anorexic or consumes nothing orally (nil by mouth) for a sustained period of time, it will need the addition of lipids, amino acids and electrolytes to provide nutritional support. There are several gastrointestinal conditions where the critically ill patients may require partial parenteral nutrition (PPN) or total parental nutrition (TPN) to prevent loss of body condition and a detrimental state of catabolism. These methods are designed to enable IV feeding to sustain life, bypassing the usual process of ingestion and digestion.

The two options are as follows:

• PPN: formulas meet some but not all of a patient’s daily nutritional requirements.
  
• TPN: formulas provide all the required nutritional needs, in a constant 24 hours/ day IV infusion.

Some clinical teams are reluctant to implement TPN because of the knowledge and equipment required, the environmental setting needed for compounding, the high cost and the complications the patient can experience. The TPN solution must be mixed in an area of the practice away from stables and bedding, preferably in a lab setting with an exhaust hood. The area and countertop must be clutter‐free, dust‐free and clean. If required, a refrigerator dedicated to TPN storage should be situated nearby. Mixing of the TPN solution should take place under sterile conditions with the operator wearing a mask, sterile gloves and a sterile gown, with an assistant to open the fluid containers, mixing bags and supplements. Once the bags are filled, air trapped in them is expelled; they are labelled with the date and time of mixing and stored in the fridge. Solutions should be discarded if not used within 24 hours of being stored [34]. It is best to formulate the mixture just before it is due to be infused.

TPN should be protected from light during administration to prevent photodegradation of its components. Several components of TPN, such as certain vitamins such as vitamin A, riboflavin, certain amino acids, and lipid emulsions, are sensitive to light. Exposure to light, especially ultraviolet (UV) light, can lead to chemical degradation or alteration of these components, rendering them less effective or even harmful. For example, exposure to light can lead to the breakdown of lipid emulsions, causing the formation of peroxides and other harmful compounds that may contribute to oxidative stress when infused into the patient.

Additionally, photodegradation of certain components may result in the formation of toxic by‐products or loss of potency, which can compromise the safety and efficacy of TPN therapy. For instance, degradation of vitamins in TPN solutions may lead to decreased nutritional value and potentially contribute to deficiencies in patients who rely on TPN for their nutritional needs.

Therefore, protecting TPN from light by using light‐resistant infusion tubing, bags, or covers during administration is essential to maintain the stability and integrity of its components.

TPN should always be administered through a non‐thrombogenic IV catheter in a large vein, this is usually the jugular vein [34]. Large volume or rapid administration of TPN is not possible due to the osmolarity of the solution and high glucose concentrations. Therefore, crystalloid fluid therapy is usually administered concurrently to maintain fluid balance [34]. Due to the potential for bacterial growth in TPN solutions, a dedicated IV catheter or catheter port that is used only for the TPN solution should be identified and maintained [34]. Administration sets should be changed daily. The components of TPN contain lipids and dextrose, the perfect media for the proliferation of bacteria. Therefore, a scrupulous aseptic technique must continue once the bag is connected to the patient. If the giving set is disconnected and inadvertently contaminated for any reason, it must be replaced. Figure 14.3 shows TPN mixed and ready to be infused. For more information on mixing and administration of TPN, please see the further reading list at the end of this chapter.

Mobility and Physiotherapy

Patients with limited mobility, accompanied by generalised weakness may require physiotherapy to prevent contractures or laxities while convalescing. Deep beds help to provide support and padding while recumbent, but the addition of soft mats to pad hips and shoulders to prevent decubital ulcers (pressure sores) may help. Basic physiotherapy techniques are covered in Chapter 17.

Modern versions of support slings are now used more frequently, having been redesigned to support the whole body in a balanced manner, without exerting pressure on the thorax and skeletal protuberances. It takes skill and experience to manage the horse in a sling, and their use is not without risks. It is important to understand the mechanics of how they function and to know how to dismantle them in an emergency to release the horse. Nursing care includes:

• Preventing friction rubs and pressure sores
  
• Monitoring orthopaedic comfort
  
• Providing mental stimulation
  
• Performing passive physiotherapy in preparation for removal from the sling
  
• Keeping the stable scrupulously clean

See the further reading section for more information regarding managing equine patients in slings.

Hygiene

Maintaining good patient and stable hygiene is important in critically ill horses as there are many ways where exposure to environmental factors could cause delays and complications in healing. Equipment used for cleaning stables and grooming should not be used on other patients, and staff working with critically ill patients should not handle the transient population of horses that enter the practice. Implementing reverse barrier nursing techniques will help prevent opportunistic infections that could devastate the immunosuppressed patient. See Chapter 6 for further information on biosecurity and infection control techniques.

Skincare

Maceration occurs when the skin has softened and broken down due to continual exposure to moisture. This could be associated with highly exudative dressed wounds and discharge from open wounds and drains. With critically ill patients that are recumbent for much of the time this is a concern, as these patients will often lie in their own urine, faeces and sweat without the ability to move away from these secretions. Such patients will require regular grooming and sponge baths of the areas affected. After the area has been thoroughly dried off, absorbent pads should be placed under the macerated areas to help prevent the formation of decubital ulcers [33]. Frequent turning and mucking out of recumbent horses will help to limit the exposure to waste materials that could cause macerated skin. Recumbent horses should be turned once every four hours as a minimum and encouraged to stay in sternal recumbency as much as possible [33]. Grooming is a good time to examine the skin and coat closely for any new lesions. If new lesions occur, they should be treated quickly by drying the affected area and applying an emollient cream [33]. Manes and tails can be plaited to prevent matting.

Maintaining Body Temperature

A healthy horse can thermoregulate, meaning they are able to maintain a constant body temperature in the presence of fluctuating environmental conditions. In a horse suffering from shock, systemic infection or other diseases, this ability may be impaired, leaving them unable to maintain a normal body temperature. To assist in keeping them warm, stable rugs and bandages are applied and stables are fitted with heat lamps. If the patient becomes pyrexic this may be counterintuitive, as they will not be able to cool themselves under thick rugs. A light‐moisture wicking cooler that moves moisture away from the body will help them to cool their body temperature without getting chilled.

To actively lower a high temperature, a continuous application of water by sponge or spray will rapidly cool a horse as it removes heat by conduction, transferring the heat from the horse to the water. Eventually, the water coming off the horse is closer in temperature to the horse. The water should not be scraped off as evaporation is much slower compared to conduction. The water must remain on the body surface to make conductive heat removal effective. See the further reading section for more information on efficient cooling techniques for horses.

Compared to humans, healthy horses have a wider thermoneutral zone and do not feel cold until environmental temperatures drop below 5 °C, or even lower if sheltered from wind and rain. The horse’s winter coat has insulating properties in sustained cold weather as long as it stays dry. The hairs will stand on end, trapping warmth from the body against the skin. Most practices will have stables equipped with heat lamps and take measures to prevent drafts from travelling through stable blocks. If a horse is not shivering, then warming methods are rarely needed. If the rectal temperature is subnormal, then drying the horse prior to rugging is recommended. The usual peripheral measures (rugging and bandages) are ineffective in restoring the body temperature to normal in these cases unless the patient has its core rewarmed. The administration of warmed IV fluids and warm water enemas can help to achieve this.

Stables must be equipped with enough bedding to prevent drafts and provide a layer of protection to the horse when it lies down. The use of rubber mats can enhance this but should not be used without a thick layer of bedding on top. The choice of bedding used depends on the condition being treated and the preference of the clinical team.

Oxygen Administration

For some disorders, it may be necessary to administer oxygen to the patient. Face masks are not routinely used in equine practice as they are difficult to keep in place and rarely seal well enough for the patient to receive sufficient oxygen. Intranasal oxygen insufflation, through a flexible oxygen tube fixed to the side of the headcollar with tape is an easily tolerable and recommended method for administering oxygen to equine patients. A flow rate of 15 L/min is recommended for adult horses [1].

Tracheostomy

Occasionally, an obstruction in the horse’s upper respiratory tract can lead to restricted air intake and respiratory distress. A tracheostomy is performed to open the airway, bypassing the pharynx to enable unobstructed breathing. The surgical procedure creates an opening in the trachea, enabling a tube to be fitted between the tracheal rings. Depending on the condition, it can be a temporary or permanent solution to the condition.

Different types of tracheostomy tubes are available for use in horses. Ideally, they should be made of a material that is easy to clean, non‐irritating and well tolerated by the horse. Short‐term cuffed and uncuffed silicone J‐type tubes are easy to fit in an emergency and can be secured with umbilical tape around the neck. Metal self‐retaining tubes have two interlocking flanges that fix it in the tracheal lumen without the need for tape ties.

Performing an emergency tracheostomy is an act of veterinary surgery and should be carried out by a vet, but the RVN can play an important role in preparing the equipment and the patient. In some circumstances, this is a lifesaving procedure. Therefore, it is essential that the surgery takes place as quickly and efficiently as possible. It is a good idea to have an emergency tracheostomy kit prepared beforehand. Contents of this kit should be as follows [1]:

• Tracheostomy tube (ideally two different sizes)
  
• Clippers
  
• Surgical scrub, spirit and swabs
  
• Sedation
  
• Local anaesthetic
  
• Scalpel blade and handle
  
• Suture material and needles

The case vet will decide if sedation is appropriate for the individual case being treated. The patient should be restrained effectively. The RVN should clip and aseptically prepare the ventral aspect of the neck. The site for tube placement is the junction of the upper and middle thirds of the neck [1].

The tracheostomy procedure will then be performed by the vet as follows [1]:

• A line of local anaesthetic is infiltrated subcutaneously at the site of tube placement.
  
• A vertical incision of approximately 5–7 cm is made through the skin and extended to the surface of the trachea.
  
• A horizontal incision (no greater than one‐third of their circumference) is made between two trachea rings.
  
• The tracheostomy tube is then inserted between the rings of the trachea and directed distally.
  
• The tube is secured in place. The method of this will depend on the type of tube being used.

Management of an indwelling tracheostomy tube requires a sustained commitment to maintaining the new open airway, preventing infection and obstructions. With a tube in place, secretions are increased and threaten to block the tube as the body responds to having a foreign object in place. The tube must be removed, cleaned and disinfected twice daily. While the tube is removed, the wound can be cleaned with any secretions removed by suction if needed. In the initial period following placement, a dressing may be placed between the skin and the tube to prevent ulceration while the wound starts to heal. These patients are prone to lower respiratory tract infections because their breathing bypasses the normal filtration of particles and contaminants through their sinuses.

A dust‐free, stable management regime is important with these horses. Initially, they will need to be box rested for monitoring of the tube, the initial adjustment to having the tube fitted. Dust‐free bedding, ideally a type that cannot be inhaled through the tube, is preferred, with all hay soaked and offered from the ground. Concentrates should not be offered from a feed manger or bucket as the horse may be able to dislodge the tube on the sides. Feeding off the floor in wide rubber tubs is preferable. These patients benefit from being stabled near busy corridors where people can frequently walk by and observe them, checking that the tube has not been dislodged.

Thoracic Drains

The insertion of large bore chest drains enables the removal of thick pleural fluid, fibrin and cellular debris that otherwise could not be withdrawn through needles. If effusion persists, they can be sutured into place and used for continued pleural lavage and drainage.

The materials used for the placement of a chest drain include:

• Ultrasound scanner
  
• Local anaesthetic
  
• Fenestrated chest tubes with a blunt trocar ranging in size (16–32 French)
  
• Scalpel blade
  
• Haemostat
  
• Nylon suture
  
• Heimlich valve or non‐lubricated condom

The horse is sedated and manually restrained as requested by the vet. The location for the tube insertion should be at the most ventral aspect of the pocket of fluid, avoiding the heart and confirmed by ultrasonography. The site is clipped, and aseptic skin preparation is carried out. The area will be rescrubbed after being blocked with a local anaesthetic. The vet will make a stab incision through the skin, and the chest drain with the blunt trocar is carefully advanced through the intercostal muscle. When the tube enters the pleural cavity, the resistance suddenly ends. The tube is advanced, so all the fenestrations are in the pleural cavity and the trocar is removed, with the free flow of fluid confirming the correct placement. A haemostat is used to clamp off the tube to prevent air ingress, while the tube is sutured in place. Purse‐string and Chinese finger trap sutures are placed to secure the tube in place. A Heimlich valve or a non‐lubricated condom with the end cut off, is fitted on the distal end of the tube to prevent ingress of air; frequent cleaning below the drainage site is required as well as the application of a barrier cream. If a rug is worn, a large kennel liner can be attached to its underside to absorb any discharge without wicking through to the rug. Stable bandages can be applied to the distal limbs of the patient to prevent scalding from the draining fluid as the horse ambulates around the stable. This can also help to minimise fluid build‐up and swelling in the distal limbs, which can be uncomfortable and limit mobility.

Haemorrhage

Haemorrhage is often the result of trauma, with external bleeding from the body being visually apparent. Acute and significant blood loss is associated with pale mucous membranes, marked tachycardia, colic and weakness that can lead to rapid deterioration and collapse. PCV can be measured to try to investigate blood loss. However, the results should be interpreted cautiously as it may take up to 24 hours following the injury to observe a significant drop in the PCV [7]. The treatment aims to prevent haemorrhagic shock and stem or limit further blood loss. In many cases, no further treatment is required once the blood loss has been controlled.

Resuscitative IV fluid therapy to treat the resulting hypovolaemia may be necessary, with careful monitoring of haematology parameters. Shock doses of up to four times the blood loss can be administered, which improves oxygenation even with a decreased packed cell volume. There are different approaches to fluid therapy, with some clinicians limiting the volumes to maintain a lower blood pressure in an attempt to slow haemorrhage. This could lead to poor tissue perfusion and oxygenation and subsequent cardiovascular collapse. Others will risk further haemorrhage by administering larger volumes of crystalloid and colloid fluids to maintain a normal blood pressure and prevent hypovolaemic shock.

As discussed earlier in this chapter, with external bleeding, direct pressure with sterile dressings and/or bandaging is the recommended method to slow blood loss from distal limbs. If the blood continues to seep through the bandage, to prevent dislodging newly formed clots, it is best to place another pressure bandage over the one in place. Tourniquets can be placed to help to stem heavy bleeding and should be positioned proximal to the wound. Tourniquets should be applied with extreme caution due to the risk of causing ischemia and necrosis if used incorrectly.

What is less evident is trauma‐induced internal bleeding. It can occur within the guttural pouches, lungs, thorax, abdomen, retroperitoneal region, intestinal lumen, musculature and pelvis due to arterial ruptures. Internal bleeding is more difficult for the vet to diagnose and requires the use of ultrasonography, haematological and biochemistry analysis, cytological evaluations and exploratory laparotomy if the patient stabilises. As discussed earlier, if the thoracic cavity has been penetrated, plastic kitchen wrap can be used to prevent ingress of air into the thorax as a first aid measure.

Treatment options are limited due to the inaccessibility of the traumatised area, but keeping the horse box rested in a quiet environment helps to limit further bleeding. If the patient is hypoxic as a result of the blood loss, intranasal oxygen should be administered. Oxygen lines can be fixed to the horse’s mane and run up through the fluid hanger in the stable, then to the outside of the stable. The oxygen canisters should be safely stored out of reach of the horse. A blood transfusion may be required if blood loss has been severe. See Section 14.9 for further information.

Wounds

Detailed wound healing and management content can be found in Chapters 12 and 13.

Traumatic wounds are dealt with in a similar manner as haemorrhages. Wounds often result in bleeding and should receive first aid pressure bandages in the first instance. With the cessation of bleeding, the wound can be flushed, debrided and assessed to identify the structures involved.

After the initial assessment, primary wound closure with sutures or staples may be attempted. A delayed primary closure may be indicated in the presence of contamination, contused or swollen soft tissues. When suturing traumatic wounds, correct skin preparation is vital. All wound edges need to be anatomically apposed, using the least number of sutures necessary to limit the chance of infection being tracked below the skin. Choosing the right suture material and technique affects the success of the closure, with synthetic monofilaments being less reactive and adding strength.

Older wounds that have a compromised blood supply make primary closure difficult, and these often need to heal by second intention. With second‐intention healing, the wound defect relies on epithelisation and contraction to close, which will significantly add to the healing time. This may also include wounds to the body that have significant skin deficits. These wounds will still require covering with innovative ways to secure dressings and bandages to prevent contamination.

Effective nursing care contributes positively to wound healing as it aims to:

• Prevent contamination and provide optimal conditions for wound healing through effective dressing selection and bandaging.
  
• Prevent self‐mutilation of the wound through effective bandaging and instigating nursing interventions if required.
  
• Promote favourable conditions for good wound healing for example, dry, clean environmental conditions, rubber flooring, suitable bedding and an appropriate feeding regime.
  
• Help the patient cope with prolonged box rest by providing mental stimulation and environmental enrichment.

Luxations

A joint luxation is a complete dislocation or complete separation between the bones that normally articulate to form a joint (Figure 14.4). A joint subluxation is a term that refers to a partial dislocation of the joint where there is still some contact between the articular ends of the bones.

With a joint luxation, the severity can range from complete instability of the joint with complete inability to bear weight on the limb to limited misalignment of the joint and a weight‐bearing capacity. Once a veterinary diagnosis has been confirmed and reduction of the luxation is performed, external coaptation for stabilisation of the dislocated joint is compulsory. If an open dislocation exists, the prognosis is guarded and may require numerous cast changes to enable access to the wound for treatment.

Depending on the severity, the horse may return to work, but osteoarthritis is a common complication even with effective immobilisation, box rest and convalescence. If reduction of the luxation cannot be sustained in the correct anatomical position, the joint becomes non‐mobile and arthritic, causing significant and chronic pain.

Foreign Bodies

Foreign bodies are objects or materials found in the body that do not originate there. They can be microorganisms like bacteria and viruses or objects that enter a body part through trauma via ingestion or inhalation. Horses are frequently treated for the removal of foreign bodies that they step on or are impaled by. They range in size from blackthorns to large stakes, and all must be managed in a way that limits further injury during investigation and removal. Those that penetrate sterile body cavities such as synovial structures, the peritoneum, intestines or the pleural cavity are of the greatest concern. Items that frequently penetrate the hoof, such as nails or wire barbs, are commonly contaminated with soil, faeces and rust. These serve as a transfer mechanism for bacteria, which can lead to severe infection.

Obtaining a detailed history will help to determine if the injury needs to be treated as an emergency that often necessitates referral. Owners should be made aware that keeping the item in situ is recommended until a vet can see the horse; a bandage should be applied around the wound using a padded ring of bandage padding, so the pressure is focused on the surrounding area and not on the foreign body itself, as this would cause further damage and deeper penetration. If a foreign body is removed before the horse is admitted to the hospital, the client should be advised to bring the object with them. The vet can examine the item to determine if any fragments remain in the wound.

Recovery can be prolonged depending on the severity of the wound and what structures are involved. The patient may be box rested to restrict mobility and encourage wound healing with limited complications. Medicinal therapy administered would be prescribed by the case vet according to the individual injury. This may include antibiotics and non‐steroidal anti‐inflammatory drugs (NSAIDs), with regular monitoring of inflammatory markers and haematology values to gauge the success of treatment. The bandage will need to be changed according to the injury and the requirements of the wound. The bandage should be monitored carefully for any damage or strike‐through of exudate. The horse’s overall comfort will need to be assessed, and regular pain soring should be carried out. As the horse is on box rest, offering plenty of forage and fibre‐based feedstuffs will help to maintain intestinal motility and help to prevent impactions. Gastrointestinal function will need to be monitored closely. Environmental enrichment should be provided, and the horse could be groomed regularly to encourage interaction, if appropriate for that individual case.

Thoracotomy

Surgery on the thoracic cavity is rarely performed due to the low incidence of disorders affecting the thorax, the poor prognosis of many conditions and the cost of the procedure and its recovery period.

Thoracotomies in patients with pleuropneumonia or abscesses in the thorax can respond favourably to this invasive surgery if medical management has had limited effect. It is achieved in the standing horse with sedation and the administration of intranasal oxygen andIV fluids. This procedure allows the removal of fibrin, purulent material and abscess debris from the pleural cavity. Sometimes, this procedure is facilitated by a rib resection to enable better access to the affected areas. Thoracotomies can also be carried out to remove neoplastic masses and partial lung resections. Scrupulous management of chest drains is vital, with measures taken to prevent air ingress and avoid infection at the insertion site. The insertion site will need to be monitored for any localised reactions, pain and swelling.

In neonates, rib fractures can be repaired by internal fixation using plates, cortical screws and cerclage wire. These foals usually incur thoracic trauma at birth or during rough handling, resulting in rib fractures or dislocations at the costochondral junction. Complications associated with rib fractures are haemothorax, pneumothorax, myocardial lacerations and contusions, with rapid death if the rib fragments perforate the heart. Internal fixation limits the damage if there are mobile fragments present but must be followed by intrathoracic suction to alleviate pneumothorax. Post‐operative nursing care includes:

• Oxygen administration
  
• Ambulatory support
  
• Administration of analgesia and antibiotics as prescribed by the vet
  
• Regular blood gas monitoring
  
• Surgical wound management
  
• Cautious handling

These foals should be allowed to rest in a position that they feel most comfortable in and quickly learn to lie down unaided.

Laparotomy

Laparotomy in the horse is the most common surgical procedure associated with colic and gastrointestinal disease. A general anaesthetic (GA) with the horse in dorsal recumbency is required to allow full access to the abdominal organs, with a ventral midline incision. While all the intestinal organs are palpable, only about ¾ can be exteriorised for resections or repairs. Following recovery, the horse should be placed in a critical care box with heat lamps and the provision to administer IV fluids. The stable should have a deep, clean bed of shavings and be well ventilated. Any medication required will be prescribed by the case vet depending on each individual case. Post‐operative colic patients require extensive, intensive care treatment and nursing care, which may include:

• Regular critical care checks (according to practice policy) to monitor pain and progress. All body systems are assessed, and clinical parameters are taken. See Chapter 17 for further information.
  
• IV catheter site checks as these patients are more prone to developing thrombophlebitis. See Chapter 17 for further information.
  
• Gastric decompression to relieve excess gas and fluid, such as enteral reflux.
  
• IV crystalloid fluids may be required as many post‐operative colic patients require limited oral fluid intake. The amount and type of fluid should be prescribed by the vet, and the amount required worked out carefully. The patient should be monitored closely. Daily serum electrolyte tests may indicate the need for supplementation.
  
• Prokinetics drugs such as lidocaine to stimulate gut movement and prevent ileus.
  
• Analgesia, may include NSAIDs such as phenylbutazone or flunixin meglumine and/or opioids such as morphine, to reduce pain and inflammation [35].
  
• Antibiotics help to prevent and treat any infection. These should be prescribed by the case vet after careful consideration of the British Equine Veterinary Association (BEVA) ProtectMe guidelines and the individual practice policy for reducing antimicrobial resistance.
  
• Polymyxin‐B to help to treat endotoxaemia [35].
  
• Repeated haematology and biochemistry analysis, including frequent lactate measurements.
  
• Surgical wound and abdominal support management. Depending on the wound closure method used, this may include changing a belly band.
  
• Environment enrichment to include grooming and walks if appropriate
  
• Periodic mouthwashes with fresh water if the patient is being starved for any length of time [35].
  
• Reintroduction to eating in the form of offering grass around 48 hours post‐op, but only if the clinical parameters are improving.

Colic patients are usually discharged from the practice 5–14 days following surgery. Each patient should be treated as an individual when it comes to a home care plan, but generally, the horse will require a period of box rest for around two months before being allowed small paddock turnout. Full turnout and ridden exercise may be introduced approximately four months following surgery depending on progress [35].

Caesarean Section

Dystocia in the mare is a true emergency and can be life‐threatening to the mare and foal. A rapid veterinary assessment with obstetrical manipulation should be carried out, moving quickly onto a controlled vaginal delivery or a caesarean section under GA if a conscious delivery is not possible. Mares have an explosive second stage of labour, and if the foal is not delivered within 90 minutes of chorioallantoic membrane rupture, its chance of survival is minimal. For this reason, some hospitals will perform a caesarean section immediately upon the mare’s arrival, forgoing the time it would take to attempt a controlled vaginal delivery.

The post‐surgical care is similar to that of a colic patient and includes monitoring and administering IV fluid therapy and medications. There may be the added challenge of having a neonate in the stable; thus, attention must be directed towards ensuring the foal does not become entangled in fluid administration lines. Abdominal dressings and support bandages help limit the formation of oedema and discourage the foal from nudging the surgical site when searching for the udder. The placenta must be removed soon after recovery, preferably within three to five hours and examined thoroughly to prevent complications from retained foetal membranes. The consequences of this are potentially life‐threatening and may lead to endotoxaemia, endometritis, peritonitis and laminitis. As a precaution, the mare may have her feet iced or placed in cold boots to assist in preventing laminitis. An abdominal drain can be placed cranial to the incision during surgery to use for large volume peritoneal flush postoperatively. Analgesia and antibiotics will be administered according to the treating vet’s instructions. Regular pain scoring and critical care checks are required.

Obstetrical treatments will include uterine flushing with a sterile isotonic solution twice daily until the syphoned‐out fluid runs clear. Extra care must be taken to limit the flush volumes as it could strain the uterine incision, risking leakage into the peritoneum. The foal should be monitored carefully, and treatment provided as required. For more information on foals, please see Chapter 15.

Hypocalcaemia

Hypocalcaemia or low blood calcium is a relatively uncommon condition but can lead to synchronous diaphragmatic flutter if left untreated. This is because the function of the phrenic nerve as it passes over the right atrium, is compromised from the electrolyte imbalance. It is stimulated and contracts the diaphragm at the same time as atrial depolarisation. These contractions cause the horse to have what looks like ‘hiccups’; this unique clinical sign is often referred to as ‘the thumps’. The abnormal stimulation of the phrenic nerve results in a synchronised heart and respiration rate.

Causes can include:

• Endurance exercise, particularly in hot weather
  
• Lactation from two weeks prior to foaling up to a few days post‐weaning
  
• Dehydration
  
• Transportation
  
• Intestinal disease
  
• Trauma
  
• Endocrinology disorders
  
• Renal failure
  
• Endotoxemia and sepsis

Hypocalcaemia is diagnosed by low serum calcium (4–6 mg/100 ml:1–1.5 mmol/L) concentrations [36]. Low serum magnesium may be found in transit cases. Treatment is with calcium borogluconate IV (given to effect) added to isotonic IV fluids [36]. The heart should be auscultated during therapy. If left untreated, the horse can develop seizures, but with urgent electrolyte rebalance, the condition is easily corrected.

Shock

Shock is defined as inadequate tissue oxygenation resulting in decreased perfusion to vital organs. The consequences of untreated shock are severe as a lack of oxygen supply to the tissues will have significant effects on all organs, in particular the brain, heart and kidneys [5]. If the state of shock is prolonged, it may lead to organ failure and death [5]. Please see Table 14.5 for the different classifications of shock.

Indications for Fluid Therapy

Fluid administration for maintenance or replacement purposes is one of the foundations of equine critical care and must be readily available for use in any equine practice. Its main purpose is to restore circulating volume and improve cardiac output, which will in turn, improve tissue perfusion and correct imbalances in electrolyte and acid–base abnormalities.

Fluid therapy is beneficial for:

• Maintaining adequate levels of hydration when disease or circumstances prevent the patient from drinking and sustaining hydration themselves.
  
• Restoring deficits that have caused dehydration.
  
• Replacing continuing fluid losses when a disease process continues.
  
• Overhydrating for treatment of a condition that requires increased fluid retention, for example, softening a large intestinal impaction.

Clinical signs of dehydration may include the following:

• The horse may appear quiet and dull
  
• Mucous membranes may be congested (dark red) and tacky to touch
  
• Increased CRT (over two seconds)
  
• Tachycardia
  
• Poor skin turgor
  
• Decreased urine output
  
• Slower jugular refill time

Haematological analysis may suggest a high PCV and an increased total plasma protein. Horses with dehydration can have biochemistry abnormalities associated with dehydration like an increased urea, creatinine and lactate. The percentage of dehydration relates to the amount (%) of body weight lost. Clinical signs relating to dehydration can be seen as follows [37]:

• Less than 5% dehydration: Clinical signs may not be apparent.
  
• 5–7% dehydration: Clinical signs may include tacky or dry mucous membranes, a prolonged CRT and mild depression.
  
• 8–10% dehydration: Clinical signs will present as above with the addition of prolonged skin tenting, weak peripheral pulses, cool extremities, moderate tachycardia and depressed mentation.
  
• 10–12% dehydration: Clinical signs will present as above with the addition of cold extremities, obtunded mentation, severely prolonged skin tenting and severe tachycardia.
  
• 12% dehydration and over: Clinical signs will present as above and the patient may be moribund or comatose, recumbent and have severe tachycardia or bradycardia.

Dehydration ranging over 10–12% is fatal if not addressed rapidly and aggressively.

Types of Fluids

A decision on what type of fluid to administer needs to be determined based on biochemistry analysis and the disease state. The standard baseline electrolyte solutions used in equine practice are 0.9% sodium chloride (saline) and balanced electrolyte solutions.

There are two categories of IV fluids routinely used in equine practice:

• Crystalloids
  
• Colloids

Infusion Pumps and Syringe Drivers

Fluid infusion pumps used in human medicine have long been utilised in equine practice (Figure 14.5). They are calibrated medical devices that draw IV solutions from a standard fluid bag through a giving set, past pumps that use a peristaltic action to deliver the fluid to the patient. They are set to a predetermined infusion rate and have mechanisms in place to prevent air ingress, as well as alarms to signal when there are disturbances to the fluid flow. They can be safely used in foals and horses of all sizes because their veins are large enough to cope with the pressures that the pump delivers on them without risk of vessel damage and extravasation. Some infusion pumps can save the total volumes infused over a specified time on their software, making it easier for the veterinary team to calculate gains against losses. The maximum rate is 999 ml/hour, which is not sufficient for maintenance infusions in the adult horse but is very useful for foals, smaller infusions and administering TPN.

Syringe drivers are also medical devices that can be used in equine practice. Smaller volumes of solutions and medications are mixed in syringes and secured to the driver. An actuator is programmed to push the syringe plunger at a set rate, delivering controlled and constant volumes to the patient.

Enteral Fluids

In some cases, enteral fluids will be required. Enteral fluids may be administered via a nasogastric tube.

The main advantages of giving enteral fluids by nasogastric tube are as follows:

• Less expensive than IV fluids
  
• Does not require sterile supplies
  
• Absorption via the gastrointestinal tract is a natural process and physiologically normal, making fluid imbalances unlikely.

Horses can comfortably receive a bolus of 6–8 l, although it is not uncommon for the stomach to accommodate about 20 l or more when gastric reflux is present. Due to the small size of the equine stomach, care should be taken not to overload the patient with fluids, as discomfort and rupture can occur. Hypovolaemia amplifies absorption in the gastrointestinal tract, and the fluids administered will enter the circulation within an hour. Administering fluids by this method is contraindicated in the presence of ileus, intestinal obstructions or marked bowel inflammation. An oral fluid delivery system can be constructed that utilises gravity‐fed administration into a soft (silicone) nasogastric tube that is fixed in place. It delivers a continuous ‘trickle’ rate of fluids into the stomach. This is only advised with patients who are standing and not showing signs of colic. Careful monitoring is required with the use of oral fluid delivery systems, as the position of the tube within the stomach can alter, and this can change the rate of fluid administration.

Administering tap water via a high enema is effective in rehydrating horses that are unable to drink. Because the permeability of the rectal mucosa is good and this method is easily tolerated, rectal fluid therapy could benefit patients who cannot tolerate nasogastric fluid administration. Sterile fluids are not required, and the risk of fluid overload is low with this method.

Indications for enteral fluids:

• Increase fluid absorption of gastrointestinal ingesta, for example, to soften large intestine impactions.
  
• Correct electrolyte imbalances
  
• Maintain a zero‐balance state
  
• Treat dehydration in the presence of ongoing losses
  
• Trigger the gastrocolic reflex, which in turn stimulates intestinal motility.

For more information regarding nasogastric tubing, see Chapter 17.

Fluid Balance

Because water is the body’s most essential nutrient, clinicians must attempt to keep patients in a zero‐fluid balance. This means maintaining a state where the amount of fluid excreted from the body is exactly equal to that which is introduced, resulting in an equilibrium. In veterinary practice, daily fluid balance is measured by calculating the difference between all intakes, such as IV fluids, enteral and/or parental nutrition, and all outputs, for example, waste excreted and losses, not including insensible losses. Insensible fluid losses are the volumes of body fluids lost in daily physiological functions that cannot easily be measured, mainly from respiration, perspiration and the water in faeces. When fluid balance is disrupted, it can lead to an altered balanced state. Negative fluid balance results in clinical dehydration as there is insufficient water content in the interstitial space. This results in less water intake than the output from faeces, urine, sweat and respiration.

Fluid overload or positive fluid balance is not perceived to be a great concern in the adult horse but should be closely monitored in neonates during fluid therapy. The most common cause is overhydration with IV fluids, which results in the presence of excess water in the interstitial and intracellular spaces. This can be a desirable effect in the presence of large intestinal impactions. Systemic overhydration from large‐volume fluid therapy forces water into the ingesta, promoting colonic secretion, which enables it to soften and exit the body. Urinary output will be increased at this time, with a diluted concentration, but should normalise once the fluid rate is returned to normal.

Other causes include an increase in total body sodium concentrations with an associated rise in extracellular water, which occurs in some disease states. These may include congestive heart failure, kidney failure, oliguria and liver failure.

Fluid Calculations

Calculating fluid requirements is estimated and depends on the clinical signs, the laboratory data and the expected characteristic of the disease condition. It considers the maintenance, deficits and projected losses over a 24‐hour period, while the horse is regularly monitored. Neonates have different daily maintenance requirements because they have greater body fluid content in proportion to the adult. Their extracellular fluid space (ECF) is also greater when compared to an adult. This, along with a higher metabolism, rapid growth and fluid losses, results in larger fluid requirements per kilogram.

Daily maintenance requirements of adult horses and foals are as follows [37]:

• Adults: 40–60 ml/kg/24 hours
  
• Foals: 80–100 ml/kg/24 hours

The percentage (%) of dehydration must be determined through haematology testing. Once the % dehydration has been determined, the litres of deficit can be calculated using the following equation:

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