ABSTRACT: The contrast between the sterile, clinical confines of the small animal theatre and the dirty, draughty farm environment, is a massive one. Dirt, dust, hair, faeces, bedding, rain, contamination of nearly every kind! So how does assisting in this location differ from that in the surgery? Correct' theatre practice isn't disregarded; but adaptability, organisation and resourcefulness take over Equipment and personnel sterility, correct preparation of the surgical site, and adequate anaesthesia or sedation are all adhered to But overcoming obstacles such as handling and restraint, equipment availability, how much help is available, difficult working conditions, and environmental contamination all make for a potentially complicated procedure and an asepsis nightmare!

The most common farm procedure requiring assistance is the Caesarean section. Nurses take part in numerous Caesareans over the course of their careers and, consequently, understand how vital an assistant is in aiding the vet with delivery of a healthy neonate, whilst maintaining the health and welfare of the mother.

A bovine Caesarean section is indicated in cases of dystocia, usually caused by malpresentation or an oversized calf. It’s also considered if there is foetal mortality and an embryotomy (dismemberment of the foetus within the uterus) is not possible. In some cases, however, it can be a pre-arranged elective procedure – for management purposes or breed- specific problems, for instance.

Be prepared!

To be able to respond fast and efficiently to a farm call, an easily transportable ‘Caesar box’ should be ready to grab when needed. This box contains the surgical kit, drugs and equipment that may be required (Table 1). The farm may be many miles from the surgery, so returning to collect forgotten items means wasted time and money.

All farm vets have stocks of medication and equipment in their cars, but maintaining a proper ‘Caesar kit’, kept within the surgery, ensures that it is available to any ‘on-call’ vet. Contents of the kit and their quantities will vary slightly according to personal preference.

On return from a visit, the box will need to be checked for breakages (commonly the box will be the item that is trodden on by the cow!) whilst the kit must be checked for losses (even large items become surprisingly invisible amongst straw and are easily left behind!). It is then cleaned (because it is usually filthy with straw, dung and blood) and then restocked, ready for future use.

Appropriate clothing

Suitable clothing is as fundamental on farm as it is in theatre, but biosecurity is just as important as sterility. All those attending a farm visit should use the following:

•   Clean overalls, which must be smart, easily washed and offer basic protection for the clothes underneath

•   Waterproofs (because farm work is a messy business) and short- or long sleeved tops with elasticated, tight- fitting cuffs around arms and wrists. Some vets wear long 'calving gowns’, similar to theatre gowns but waterproof. All are easily cleaned and disinfected, offering protection for the wearer and preventing the spread of disease from farm to farm

•   Wellington boots are imperative!

•   They must be scrubbed and disinfected properly between procedures and farms

•   A warm hat and thermal underwear is also highly recommended in winter!

Handling and restraint

Before any examination begins, the patient must be suitably restrained – ideally, contained within a cattle crush with side openings for easy access to her abdomen. A ‘yoke’ secures her head and neck, whilst side bars give minimal sideways movement. Belly straps running underneath support her weight should she try to lie down.

These modern crushes are expensive and not many farms will have such an ‘ideal’ situation (Figure 1).

Figure 1: Ideal restraint for a Caesarean operation

In many cases a halter is placed on the cow’s head and tied to a strong, immovable structure; (cows have incredibly strong necks, so tying to a flimsy gate is not recommended!). Once secured, she is examined by the vet and if the decision is made to perform surgery, preparation can begin.

The patient’s temperament and health status, and the vet’s personal preference, will dictate whether sedation is used and how much. This is commonly xylazine (Rompun, Bayer) and will be injected by the vet intravenously, usually via the jugular vein.

Most surgical procedures in ruminants are performed under sedation rather than a general anaesthetic, so the animal remains standing throughout. The risks of sedation are also far lower for both the cow, and importantly, the calf.

Ruminants are prone to bloat, regurgitation, hypoventilation and poor arterial oxygenation if recumbent for any length of time, and are more likely to suffer post-anaesthetic myopathy and neuropathy. The ideal dose of xylazine (0.05-0.1 mg/kg IV) should facilitate adequate sedation, but avoid recumbency and the side effects of higher doses and general anaesthesia.

Setting up the 'theatre'

Whilst the vet is administering sedation, the nurse can prepare the kit and equipment.

Two buckets of warm water are required – one for preparation of the surgical site, and the other for personnel use. A source of electricity must be identified to power appropriate lights and for the electric clippers.

A makeshift ‘theatre trolley’ may be created out of anything from a wheelbarrow to a bale of straw. It must be positioned far enough away to avoid being trodden or kicked if the cow moves, but close enough for access to instruments (Figure 2).

Figure 2: Surgical kit ready for action

Clippers, local anaesthetic, 30ml syringes, 18G x 1.5" needles, cotton wool and antibacterial scrub are the initial requirements, then the surgical kit and suture materials.

Preparing the patient

The left para-lumbar fossa (the concave area in the upper part of the flank, bordered by the last rib and costal arch, the lumbar transverse processes and by the tuber coxae) is clipped and prepared surgically with aseptic scrub.

The nurse should follow correct surgical site preparation – scrubbing from the centre outwards as well as from top to bottom of the site, taking account of the upright position of the cow, to avoid water running down over any pre scrubbed area.

The vet will inject local anaesthetic in the form of an ‘L’ block, or line bloc; or will undertake para-vertebral anaesthesia. The most common technique is the *L’ block, so called because of the upside- down L-shape line of injections into the subcutaneous tissue and muscular layers of the abdominal wall. Essentially this forms a ‘wall’ of anaesthesia, desensitising the flank for a standing laparotomy.

The nurse can be drawing up local anaesthetic whilst the vet is injecting, and exchanging full syringes for empty ones. This saves time, as around 100ml will be used in total. The surgical site is scrubbed a second time whilst the vet is preparing for surgery. Hands, arms and the front of the waterproofs are all scrubbed. The surgical kit can be passed aseptically to the vet who will lay out the instruments to suit, on the instrument trolley.

If the cow is a little fractious, holding the tail in a constant, upright, vertical position can help to discourage her from kicking whilst the vet begins surgery. Alternatively, the nurse may be required to ‘scrub in’ to pass and hold instruments, or act as a ‘human retractor’ to aid visualisation of the uterus.

Surgery

The vet makes a 20-30cm vertical incision in the left flank through the skin, then blunt dissection of the external and internal abdominal oblique and transverse muscle layers. An incision is then made into the peritoneum, caudal to the rumen. The position of the foetus is identified and an incision is made in the uterus over the metatarsal/metacarpal area (depending on whether the calf is presented in anterior or posterior position).

Once the calf’s lower legs have been exteriorised, a co-ordinated effort from both vet and scrubbed assistant/s applying suitable downward traction will facilitate removal of the calf from the uterus.

Following delivery, the uterus is closed with an absorbable monofilament material, such as Vicryl, using a continuous inverted suture pattern. Uterine contraction is rapid, especially if xylazine sedation has been used, and the scrubbed nurse may be required to hold on to either side of the ever-shrinking uterus to enable the vet to close the incision as quickly as possible. A grip of steel may be needed! (Figure 3).

Figure 3: The rapidly contracting uterus

The vet will also aim for fast but efficient suturing of muscle and skin, allowing the mother to attend to her calf as quickly as possible.

Antibiotic spray is applied to the closed skin wound and injections of oxytocin, antibiotics and non-steroidal, anti-inflammatories, such as meloxicam (Metacam, Boehringer) are all given.

Care of the neonate

Ensure that the calf’s airways are clear by removing foetal membranes from the nostrils and mouth. The calf can be suspended by its hind limbs to assist drainage. Rubbing the body vigorously with straw will stimulate breathing.

The respiratory rate should be 20-40 brpm and assessment of pulse rate and quality should reveal a normal heart rate of 90-110 bpm. The mucous membranes should be moist and pink, with a CRT of <2 seconds.

Prevent hypothermia by providing deep bedding and a draught-free environment. The calf’s rectal temperature should be around 37°-38°C (100°-102°F).

Finally, remember that too much human interference may contribute to rejection of the calf; but obviously the need for stimulation and/or resuscitation will far outweigh the potential risks (Figure 4).

Figure 4: A healthy newborn calf

This picture of an uncomplicated bovine Caesarean section is straightforward, but there are a number of complications that can give rise to a far more demanding procedure. Personal preference on the part of the veterinary surgeon will mean that the supporting nurse must be flexible in his or her approach as there are a number of potential variations in the drugs used, patient and incision positioning and suture materials.

Dealing with such ‘large’ animals means that a nurse needs to be physically strong, as well as aware of the potential dangers, to ensure the safety of all involved. These attributes, thankfully, are needed to a far lesser extent in the small animal theatre.

Uncomfortable conditions are invariably the norm, where dripping sweat or freezing cold may be encountered compared to a small animal theatre where the weather is nothing more than a passing comment!

Finally, the mess – whilst similar in principle to any Caesarean – will be on a much, much larger scale. Thankfully for the nurse, however, there is no scrubbing down of walls and floors post op! 

Author

Fiona Lord RVN MBVNA A1

Fiona began nursing in 1999. Since qualifying, she has worked in both mixed and small animal practices, gaining most experience as a locum before joining her current practice seven
years ago. During her time in small animal nursing, her interests included emergencies, critical care and medical nursing; but having discovered an interest in the large animal side of the practice, Fiona is now the dedicated Farm Animal Nurse’.

To cite this article use either

DOI: 10.1111/j.2045-0648.2012.00170.x or Veterinary Nursing Journal Vol 27 pp 164-167

Veterinary Nursing Journal • VOL 27 • May 2012 •