This week, Prof John Williams specialist in small animal surgery provides vets with an update on one of the genuine emergencies we see in dogs.
Having been busy co-editing and writing for the new edition of the BSAVA Manual of Canine and Feline Abdominal Surgery, I was researching for the updated chapter on Gastric Dilatation & Volvulus (GDV) and thought it would be a good time to bring the findings of a paper on 306 cases of this life threatening condition to people’s attention (Mackenzie G, Barnhart M, Kennedy S, DeHoff W, Schertel E. A Retrospective Study of Factors Influencing Survival Following Surgery for Gastric Dilatation-Volvulus Syndrome in 306 Dogs. J Am Anim Hosp Assoc. 2010 Mar;46(2):97–102.)
The most striking feature of this study is that survival rates are improving, with a reported overall mortality of 10%, and those cases which simply underwent derotation and gastropexy the mortality was only 3%. The mortality rate did increase to 20% when gastrectomy and splenectomy were performed, this again is lower than previous reports where it is over 30%. Previously, overall mortality rates of around 15 – 50 % have been commonly reported for this acutely life threatening disorder.
The take home messages for me, from this paper were
-All the cases were referred to a surgical referral centre.
-There is some leeway in time from the onset of clinical signs before surgery needs to be performed.
-Total fluid resuscitation appears to be the key step in successful survival of these patients.
*Though patient stabilisation and surgery still needs to be carried out in a timely fashion.
-Anaesthetic times were less than half those previously reported -though not statistically significant- the mean surgical time was 48 minutes (median time was 30 minutes).
There are clear and well identified statistically significant factors which increased the mortality rate in this study.
-Pre-operative cardiac arrhythmias
*4 out of 12 dogs with intermittent ventricular arrhythmia died
*No dogs with ventricular tachycardia died
-Carrying out splenectomy alone (15% mortality)
-Performing gastrectomy alone (9% mortality)
-Splenectomy combined with partial gastrectomy (20 % mortality)
-Postoperative cardiac arrhythmias
*4 out of 28 dogs that developed ventricular tachycardia died
*Intermittent ventricular arrhythmia postoperatively did not significantly affect mortality
Interestingly in this report there was a lower mortality rate for those dogs that had an ‘increased time from presentation to surgery’. This clearly goes against the logic that surgery should be carried out as soon as possible to minimise the risk of tissue ischaemia and its sequelae. The authors argue that their goal was complete fluid resuscitation prior to anaesthesia and surgery and that they aimed to achieve this in a timely manner. In their study the median time from presentation to surgery was one hour, the shortest time interval was 15 minutes and the longest 5 hours. Another factor which was of great interest was that the duration of clinical signs had no effect on the mortality rate, the median duration was 6 hours with a range of 2- 12 hours.
So, plenty to consider that may change your view on management of GDV. In the initial stages your main goal has to be fluid resuscitation in these patients. Secondly gastric decompression is important to prevent impairment of venous return. But once the dog is stabilised the option is there to refer to a specialist surgeon to complete the surgery. GDV needn’t strike fear into the front-line vet and at Northwest Surgeons the team of specialist surgeons and anaesthetists are poised to help you at any stage.
Full Article >