Equine Health Update EHU Vol 19 Issue 3 - Page 33

EQUINE | Proceedings Care should be taken when extrapolating these results to other populations, although the large patient num- bers in most of the studies and the long follow-up times mean the data are strong and should provide clinicians all around the world with useful information. Long-term survival rates approximately one year after colic surgery have been reported to lie between 66 and 91% (Proud- man et al. 2002; Mair and Smith 2005; Mueller et al. 2009; Mezerova and Zert 2008; Christophersen et al. 2011). In a study investigating the pattern of post-operative survival in all horses undergoing exploratory laparot- omy for colic signs (excluding horses with a confirmed diagnosis of grass sickness), there was marked mortal- ity in the days immediately following surgery leading to a cumulative probability of survival of over 0.8 by 10 days postoperatively. This was followed by a period of lower mortality up to approximately 100 days post-op- eratively. Beyond 100 days postoperatively the gradient of the survival curve was less steep, possibly represent- ing a similar mortality to the general equine population (Proudman et al. 2002). Numerous studies have highlighted the prognostic value of clinical parameters representing cardiovascular compromise in predicting survival of horses with colic (Proudman et al. 2002; Proudman et al. 2005a; Proud- man et al. 2005b). Early referral prior to deterioration in the cardiovascular status of any horse with colic will increase long-term survival. A study investigating factors associated with reduced long-term survival in horses undergoing exploratory laparotomy concluded that the following variables ad- versely affected outcome (Proudman et al. 2002): the presence of an intenstinal entrapment in the epiploic fo- ramen, an increased pre-operative packed cell volume, increasing length of intestinal resection, and increasing duration of surgery. As stated before, it has been recog- nised that patterns of survival and key prognostic indi- cators, differ between various types of colic. It is there- fore useful to review the patterns of survival and factors influencing survival that have been reported for various types of colic. Small Intestine Post-operative ileus, repeat laparotomy and elevated post-operative heart rate have been identified as factors reducing short-term survival following small intestinal resection (Morton and Blikslager 2002). Reduced long- term survival of horses recovering from surgery of the small intestine has been shown to be associated with decreased pre-operative total protein and increased pre-operative packed cell volume, increasing duration of surgery and repeat laparotomy (Proudman et al. 2005b). Epiploic Foramen Entrapment Epiploic foramen entrapment (EFE) has been associ- ated with reduced long-term survival following surgery compared to other small intestinal lesions (Proudman et al. 2002; Proudman et al 2005a). A multicentre, interna- tional study describing survival and factors associated with increased likelihood of mortality of horses with EFE undergoing surgical treatment concluded that 78.5% of horses survived to hospital discharge, 50.6% survived to one year, and 34.3% survived to two years. The risk fac- tors associated with reduced survival in horses with EFE were a high pre-operative packed cell volume, increased length of small intestine resected and post-operative il- eus (Archer et al 2011). Type of anastomosis used during a small intestinal re- section Horses with a side-to-side anastomosis were at sig- nificantly increased risk of post-operative colic and the presence of a side-to-side jejuno-caecal anastomosis was significantly associated with reduced survival time (Proudman et al. 2007; Freeman et al. 2000). • Volume 19 no 3 • September 2017 • 33