On arrival at the hospital the rabbit should have a thorough examination and detailed history taken from the owner by the veterinary surgeon. Most practices will have history forms for each specific species. It is useful for the veterinary nurse to know the normal parameters when dealing with this type of animal, but it is more important to know the presenting parameters for the individual patient. How can we be expected to assess and gauge the nursing care and recovery if we don't have a starting point? Nurses should get used to auscultating the heart and lungs, assessing the pulses and respiratory pattern before any procedures are carried out; this knowledge can then be used in the assessment of a successful recovery.
Normal Ranges
The normal ranges for the rabbit are presented in Figure 1.
The average daily food intake has huge variation due to age, size, environmental temperature, reproductive status and the diet that is normally fed. Whilst not forgetting the health status of the rabbit, disease factors and recovery usually increase the energy requirements but tend to decrease the individual's food intake. Weighing daily and the use of body condition scoring will help with nutritional assessment; the monitoring of faecal output is also useful.
The rabbit's urine is normally clear to cloudy in appearance and may contain triple phosphate or calcium carbonate crystals. Sometimes it may be seen as dark red or orange; this can be related to the excretion of porphyrins which are usually released in times of stress, or when the diet contains too much carotene. To assess whether the colour change is more serious and potentially haemorrhagic a dipstick and microscopic examination are needed.
Figure 1. Normal parameters for the rabbit.
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Bodyweight
(kg)
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Respiratory
rate (bpm)
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Heart/pulse
rate (bpm)
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Body
temperature
(°C)
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Daily water
consumption
(ml/kg)
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Daily urine
production
(ml/kg)
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Up to 6 kg depending on breed of rabbit
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30–60
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150–300
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38.5–40.0
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50–150
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10–35
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Preanaesthesic Preparation
Along with the physical examination it is advisable to take a blood sample to assess the health status of the patient prior to anaesthesia. Many blood analysers have a pre-anaesthetic assay programmed. If there are any concerns over the results then radiography and/or ultrasonography may be indicated. Fluid therapy may be necessary and there might be the possibility of postponing anaesthesia until the patient is more stable.
Rabbits do not need to be starved before anaesthesia as they cannot vomit, although food can be taken away 1–2 hours before so no food is in the oral cavity which can inhibit intubation.
All the equipment for anaesthesia, surgery and recovery should be prepared before induction; this reduces the length of anaesthesia and the potential for prolonged recovery times. Intravenous access routes can be clipped and prepared with local anaesthetic cream to reduce any response to venepuncture; this can be done easily in the ward 15–30 minutes before placement of the 23–24gauge catheter. The veterinary surgeon may also choose to premedicate the patient depending on which anaesthetic protocol they are using.
Anaesthesia and Recovery
The commonest problem seen during anaesthesia in rabbits is respiratory arrest, usually due to an underlying respiratory problem, but it can be due to the anaesthetic regime used. Some injectable drug dosages for induction can be quite high compared to those used for dogs or cats, making the respiratory depression side effects even more pronounced. Some inhalational agents cause excessive breath holding and bradycardia. Intubation is always advisable as assisted ventilation is difficult to maintain on a facemask. If the surgery is on the oropharynx, nasal catheterisation can be used as a form of intubation; this also has its place in recovery for the provision of oxygen therapy.
Lubricate the eyes during anaesthesia as the globe is very prominent and tends to dry, causing irritation, ulceration and abrasions on recovery.
Monitoring Equipment
Monitoring equipment is used during anaesthesia but also for postoperative recovery, especially of critical patients.
Pulse oximeter - gives readings on adequacy of oxygenation and also information on heart rate.
Blood pressure monitoring - either by direct (arterial line) or indirect methods (Doppler and blood pressure cuffs).
Respiratory monitors - may not be reliable when respiration is depressed. Ventilators are becoming more widely used in practices.
ECG - bradycardia due to heart block is the most common abnormality and precedes cardiac arrest. The machine used should be able to detect low-strength signals along with high level of frequency.
Thermometer - most patients become hypothermic during anaesthesia and this is a major factor in prolonged postoperative recovery. Regular checks should be made and the provision of heated blankets or tables in the operating suite, or hot water bottles/ gloves should be made. Temperature should also be carefully monitored throughout recovery.
Oesophageal stethoscope - allows monitoring of both cardiac and respiratory function in larger rabbits.
Postoperative Care
Figure 2 presents important features of postoperative care.
Figure 2. Important features of postoperative care.
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Basic hospital cage
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Quiet ward preferably away from other animals that may be seen as predators. Ideally facing into the middle of the room so they can't see each other and displays of aggression from other rabbits. Rabbits have acute sense of smell so either treat first before dealing with other patients or change clothing.
Wire-fronted cages, so unobtrusive observation can occur, but also for ventilation and reduction of overheating. Ambient environmental temperature of 21–23°C, no higher than 27°C as heatstroke will occur. Paper-lined with provision of hay and bedding material, adequate food and water bowls. Hide-boxes for insecure rabbits to reduce stress.
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Basic recovery kennel
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Heat source until the patient has fully recovered, regular temperature taking to ensure not overheating.
Environmental temperature 30–35°C until righting reflex returns then 25–30°C and then reduce to 20–25°C when fully recovered. Dimmed lighting to reduce stress in recovery. Soft bedding so corneal abrasions do not occur on recovery. Food and water supplied as soon as sufficiently alert.
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Recumbent patients
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Extra padding in kennel to reduce occurrence of pressure sores. Regular bed checks for urine and faeces to reduce risk of skin scalding. Regular turning if needed.
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Surgery wounds
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No shavings or anything that can contaminate the wound. Soft padding if needed.
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Incubators
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Provision of oxygen, heat and humidity useful for young or very ill animals.
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On a daily basis the patient should be weighed, faecal and urine output monitored, food and water consumption measured and all recorded on kennel sheets, along with clinical observations, body temperature, and pulse and respiration rates.
Sudden changes in bodyweight can provide an indication as to the degree of dehydration
Smaller faecal pellets or a decrease in number can indicate decreased appetite
Decreased urine output can indicate reduced kidney function or dehydration
Increased temperature, respiration and heart rate could indicate infective process
Reduced pulse quality could indicate shock
Lack of movement could indicate pain
Hydration status should be assessed in an area that is relatively hairless - inguinal region, inside of pinnae or scrotal skin. Intravenous catheters should be placed prior to anaesthesia, especially if the blood tests reveal a degree of dehydration, and intravenous fluid therapy should be continued until the patient is eating and drinking sufficiently to sustain hydration levels. If an intravenous route is not accessible then an intraosseous catheter can be used, although care is required if metabolic bone disease is suspected, or spontaneous fractures could occur. Maintenance rates of 2–4 ml/kg/hr can be administered. If the patient is in shock then 50 ml/kg for 1 hour can be administered, but the rate should then be reduced to the maintenance rate.
On recovery the most immediate nursing task is to get the patients to eat. Anorexia for more than 48 hours is potentially life threatening, and obese patients are at risk of hepatic lipidosis. Always provide appropriate food; sudden diet changes can be fatal. A fresh water supply in a suitable container for the rabbit, i.e., a bowl or drinking bottle, should be provided. All the dietary details should be taken in the history on admission so the rabbit's normal foods can be obtained for the duration of the hospital stay. Now is not the time to be forcing an already stressed, potentially ill patient to completely change its diet. Ensure the food is fresh and all pelleted diets are in date, as stale food will also discourage the patient from eating. An unbalanced diet or sudden change due to infection, toxins or administration of certain antibiotics will alter the gastrointestinal microflora resulting in maldigestion and ileus.
The rabbit's digestive system should be in a constant state of movement and the stomach is never normally empty, usually containing a moist lattice of food/fibre and fur. When the rabbit becomes stressed the gastrointestinal tract slows down due to the release of adrenaline, ingesta then spends more time in the stomach. As the rabbit stops eating or drinking it reabsorbs any fluid from the stomach into the bloodstream; this then causes the lattice within the stomach to form a hard ball with the potential for causing obstruction and gastric stasis.
The caecum contains small amounts of potentially harmful bacteria (Clostridium and Escherichia coli). These are kept under control by feeding plenty of fibre but not too much protein and carbohydrate. If the bacteria start to multiply endotoxins are produced which can cause rapid and fatal disease.
If the patient does not eat then assisted feeding is needed. There are highly palatable and high-fibre diets available to the veterinary practice which can be made into a gruel and syringe fed throughout the day. If syringe feeding is not well tolerated then naso-oesophageal tubes have been illustrated although care does have to be taken to ensure there are no respiratory problems as rabbits are obligate nasal breathers. Another regime used by some veterinary surgeons is to stomach tube the rabbits prior to recovery from anaesthesia to help reduce risk of gastrointestinal ileus. Oesophagostomy tubes could also be used, although the patient needs to be stable enough to undergo an anaesthetic for this procedure.
Prokinetics can be given perioperatively as pre-emptive treatment, one single injection may be sufficient to stimulate gut motility. Where there is prolonged ileus treatment should be more aggressive where a combination of drugs may be needed.
Pain management promotes healing, feeding and recovery. Assessing pain in rabbits can sometimes be difficult as they do not show overt behaviour. Clinical signs include increased respiration, polydipsia or adipsia, anorexia, reduced faecal output, altered behaviour and posture. Pain relief should be given during surgery and continued into recovery.