Cardiovascular effects of N-butylscopolammonium bromide and xylazine in horses : Effects of N-butylscopalammonium bromide and xylazine in horses

The cardiovascular effects of medetomidine, detomidine, and xylazine in horses were studied. Fifteen horses, whose right carotid arteries had previously been surgically raised to a subcutaneous position during general anesthesia were used. Five horses each were given the following 8 treatments: an intravenous injection of 4 doses of medetomidine (3, 5, 7.5, and 10 microg/kg), 3 doses of detomidine (10, 20, and 40 microg/kg), and one dose of xylazine (1 mg/kg). Heart rate decreased, but not statistically significant. Atrio-ventricular block was observed following all treatments and prolonged with detomidine. Cardiac index (CI) and stroke volume (SV) were decreased with all treatments. The CI decreased to about 50% of baseline values for 5 min after 7.5 and 10 microg/kg medetomidine and 1 mg/kg xylazine, for 20 min after 20 microg/kg detomidine, and for 50 min after 40 microg/kg detomidine. All treatments produced an initial hypertension within 2 min of drug administration followed by a significant decrease in arterial blood pressure (ABP) in horses administered 3 to 7.5 microg/kg medetomidine and 1 mg/kg xylazine. Hypertension was significantly prolonged in 20 and 40 microg/kg detomidine. The hypotensive phase was not observed in 10 microg/kg medetomidine or detomidine. The changes in ABP were associated with an increase in peripheral vascular resistance. Respiratory rate was decreased for 40 to 120 min in 5, 7.5, and 10 microg/kg medetomidine and detomidine. The partial pressure of arterial oxygen decreased significantly in 10 microg/kg medetomidine and detomidine, while the partial pressure of arterial carbon dioxide did not change significantly. Medetomidine induced dose-dependent cardiovascular depression similar to detomidine. The cardiovascular effects of medetomidine and xylazine were not as prolonged as that of detomidine.

Although short-term survival rates following small intestinal resection reportedly range from 48-88%, there is little information on predicting which horse may or may not survive small intestinal (SI) resection and anastomosis. The aim of this study was to identify factors that contribute to nonsurvival in horses following small intestinal resection. Medical records of horses which recovered from anaesthesia following SI resection were reviewed. Clinical and surgical variables were evaluated for their association with short-term survival using logistic regression and were reported as odds ratios (OR), including the 95% confidence interval (CI), indicating the likelihood of horses not surviving to hospital discharge. Ninety-two records met the criteria for inclusion. Thirty-six (81.8%) of the horses that underwent jejunojejunostomy (JJ) and 34 (70.8%) of the horses that underwent jejunocaecostomy (JC) survived to discharge. Multiple logistic analysis indicated that postoperative ileus (OR = 29.7; 95% CI 2.5-354.6), repeat celiotomy (OR = 18; CI 1.7-187.6), and an elevated heart rate of > or = 60 beats/min (OR = 5.6; CI 1.5-20.6) were the principal factors associated with nonsurvival. A low total plasma protein of <55 g/l (OR = 1.8; CI 0.-7.6) was incorporated in the final model because its inclusion improved the overall validity of the model, Clinicians should be aware of the factors associated with the greatest likelihood of nonsurvival following small intestinal resection, so that they can institute aggressive treatment and accurately inform owners on the likelihood of survival.

To investigate the effects of hyoscine butylbromide and an inflatable rectal balloon catheter on luminal distention during computed tomographic (CT) colonography. One hundred thirty-six subjects undergoing CT colonography were randomized to receive either 20 mg or 40 mg of hyoscine butylbromide or no spasmolytic. Subjects were also independently randomized to undergo CT colonography with an inflatable rectal balloon catheter or a standard thin rectal tube. Multi-detector row CT colonography was performed with patients in prone and supine positions, with colonic segmental distention assessed by a single observer with a four-point scale. A simple assessment of whether distention was adequate for clinical interpretation was also made, and the effect of hyoscine butylbromide and catheter use was examined by using multivariate ordered logistic regression. Administration of hyoscine butylbromide was associated with significantly improved cecal (P =.05), ascending (P =.001), and transverse (P <.001) colonic distention when patients were supine and improved ascending (P <.001) and descending (P <.001) colonic distention when patients were prone. Compared with control subjects, patients given a spasmolytic had odds of 6.49 for clinically adequate distention throughout all colonic segments (P =.001). There was no incremental advantage with use of a 40-mg dose. In contrast, rectal balloon catheter use was not significantly associated with improved distention. Hyoscine butylbromide improves colonic distention during CT colonography and should be routinely administered where it is available. Use of a thin rectal tube for insufflation is adequate. Copyright RSNA, 2003