SPEAKERS at the ESFM congress challenged some of the more traditional concepts in feline surgery.
According to the RVC’s Sandra Corr, for example, the idea of the “golden period” of wound infection – i.e. that contaminated wounds treated within a short time period are less likely to get infected – has fallen out of favour.
Surgeons now believe that whether a contaminated wound becomes infected or not is more likely related to two other factors: how much initial contamination there was and what blood supply to the wound is like.
Armed with this new knowledge, vets are advised not to rush into closing a wound. Dr Corr said: “We used to talk about a golden period of six hours. People now realise it’s not the time but the level of contamination and the extent of the ischaemia that matter and will tell you whether a contaminated wound will become infected or not. And, if you try to close these too soon, this can inadvertently result in infection.”
Dr Corr gave delegates an excellent, and very practical, guide to feline surgical emergencies. She highlighted open fractures, shearing injuries, conditions with nerve involvement and the less frequent septic arthritis as “true emergencies” – those that should not be left to the following day.
Another development in companion animal surgery is the recognition that measures against iatrogenic infections – including those involving MRSA and other resistant bacteria – need to be considered. Whereas a road traffic accident degloving injury can be full of debris, the real danger now is from inclinic micro-organisms.
According to Dr Corr, a key objective with an open wound is to prevent further contamination. The injury should be handled from start to finish in sterile fashion.
This point was reinforced by Dr Tim Hackett of Colorado State University who said: “Don’t get the inhouse bacteria into degloving wounds. I’m not worried about debris from the street – it’s the bacteria that live on the bottom of my treatment table that will cause problems.”
With open fractures or shearing injuries, the wound should be given a thorough flush – often with 2-3 litres of a sterile fluid. Hartmann’s is a good choice and, according to Dr Corr, additives such as chlorhexidine or antibiotics are not necessary. With regards to identifying what bacteria are present in an open wound, Dr Corr explained that swabbing did not always produce results. However, if you are going to swab, do so after the flush, not before, as it’s the organisms that remain afterwards that are more likely to infect.
As Dr Corr said: “You don’t often culture useful organisms but it’s a waste of the client’s money to swab before lavage.”
Another simple tip for helping open wounds to heal is to use wet-to-dry dressings. These are saline- or Hartmann’s-soaked swabs that are put against the wound surface and bandaged in place. As they dry they attach to necrotic debris and can be pulled away, gently debriding the wound.
Stop using them when granulation tissue starts to appear (usually in a couple of days), as you won’t want to lift this tissue off.
Expensive but effective
John Williams, of Oakwood Veterinary Referrals, also recommended a silverbased dressing called Acticoat. According to John, this product, which is soaked in sterile water and then placed directly onto the wound, is expensive but effective at killing bacteria.
“It’s not a cheap option,” he explained, but is said to kill some 99% of antibiotic-resistant bacteria including Pseudomonas and MRSA.
Another key point was the need to make sure that trauma cats received adequate nutrition. All of the surgeons advocated the use of the oesophagostomy tube. It is better tolerated than a nasogastric tube as it allows cats a more natural mobility and patients can go home with the tube fitted.
An oesophagostomy tube can be fitted when the cat is under general anaesthetic for another procedure and a premeasured feeding tube – Tim Hackett recommends a 20 French size – can be placed and checked radiographically. The tube should not extend through the gastrooesophageal sphincter as this can cause reflux oesophagitis.
With an oesophagostomy tube cats aren’t restricted to a liquid diet and owners can feed their cat a blended version of its normal diet (although it is recommended that this is tested in-practice first to check the food is suitable).
Laurent Garosi, of Davies Veterinary Specialists, was on-hand to discuss trauma to the nervous system. He said that neurological evaluation should not be overly complicated, and that a good clinical exam could give more information on prognosis than expensive diagnostic imaging techniques such as MRI. Most owners, he said, simply wanted a “functional cat” at the end of treatment.
A key area to assess is the brainstem – if this part of the brain has been damaged then the prognosis for recovery is much poorer. Vets should be aware of the signs of brainstem damage such as a decreased level of mental status, abnormal posture and an absence of reflexes such as the oculocephalic reflex.
