110 Carl F. Ihler et al. type of the intestinal lesion is often difﬁcult (Blikslager & Roberts 1995). The identiﬁcation of signiﬁcant clinical and laboratory variables for the prognosis might therefore be useful when taking the decision whether to let the pa- tient undergo further treatment or not. From an animal welfare point of view a reliable prognosis is also important when veterinarians in general practice consider transportation of severe clinical colic cases long distances for further treatment in hospitals. From a multivariable model Parry et al. (1983) concluded that variables assessing cardiovascu- lar function were good prognostic guides. From other studies clinical and laboratory variables such as heart rate, packed cell volume (PCV), colour of mucous membranes, capillary reﬁll time (CRT), acid- base variables and plasma lactate are valuable prognostic predictors (Pas- coe et al. 1990, Reeves et al. 1990, Sandholm et al. 1995, Furr et al. 1995, Thoefner et al. 2000). The ﬁbrin degradation product, D-dimer, is valuable in assessment of the cardiovascular status. Increased levels indicate that excessive amount of ﬁbrin is formed within the vascular system as a result of disseminated intra-vascu- lar coagulation. D-dimer is of special interest because the values can be measured as a horse side test. Sandholm et al. (1995) concluded that D-dimer values in plasma were valuable as a predictor for outcome in equine gastrointestinal colic cases. The purpose of the present study was to evalu- ate clinical and laboratory variables as prognos- tic indicators in medically and surgically treated colic cases in a hospital situation. Materials and methods Cases The present study was a prospective study con- sisting of 106 horses with colic symptoms caused by gastrointestinal disorders referred to The Norwegian School of Veterinary Science, Acta vet. scand. vol. 45 no. 1-2, 2004 by veterinarians in general practise for further examination and treatment from March out De- cember 1997 (50 horses) and 1999 (56 horses). In the 2 periods of the study all referred colic cases were included. The horses were all non- responders to the initial treatment in general practise such as non-steroid anti-inﬂammatory drugs (NSAIDs), ﬂuid therapy and laxatives. In 14 horses, for which the clinical examination indicated that surgical treatment was required, such treatment was not performed due to eco- nomical or other reasons. These horses were eu- thanised and excluded from the study. Of the ﬁnal 92 horses 30 horses were warm- blooded riding horses, 15 Norwegian cold- blooded trotters, 15 Standard-bred trotters, 16 Thoroughbreds and 16 horses of different pony and pleasure horse breeds. The age ranged from 6 months to 25 years (median = 8.0 years). Horses discharged from the hospital in good general condition without any signs of colic were classiﬁed as survivors. For survivors the hospitalisation period ranged from 3 to 16 days. Non-survivors were all euthanised when con- sidered to be at the terminal stage, where no re- sponse to treatment of the life threatening clin- ical situation, was detected. This was done to prevent unnecessary suffering. Clinical examination All horses were clinically examined immedi- ately after arrival in the hospital according to a standard protocol. Rectal temperature (°C), de- gree of abdominal pain (1-3), heart and respira- tory rate (per min), colour of mucous mem- branes (normal, abnormal), CRT (sec), ab- dominal auscultation (no sounds, decreased, normal and increased activity), rectal examina- tion ﬁndings and any reﬂux of gastro-intestinal content through a naso-pharyngeal tube (0-1) were recorded. The colour of the mucous mem- branes was assessed using the gingival mem- brane and classiﬁed as normal or abnormal (hy-