A number of drugs influenced the accuracy of the LiDCO sensor in vitro but, based on published pharmacokinetic data, only xylazine, ketamine, lidocaine, and rocuronium may cause biases at clinically relevant concentrations. These findings need to be confirmed in vivo. Relevant (>3 mV) changes in sensor voltages due to the presence of drugs may indicate possible interactions with the LiDCO sensor.

ABSTRACT:The first case of post anaesthetic myelopathy in a horse is described. A two year old 530 kg Shire stallion underwent surgical removal of a granuloma in the ventral sternal region under general inhalation anaesthesia in dorsal recumbency. Total duration of the operation was 85 min. The anaesthesia was uneventful except for profuse sweating and arterial hypertension observed during the whole period. During recovery the horse was not able to stand, and flaccid paralysis of hind limbs, absence of reaction to an induced pain stimulus on the hind limbs and no patellar or anal reflex was recorded; in addition, tail tonus was weak. Panniculus reflex was absent distally from the 17 th intercostal space. Head, neck and front limb movement was not affected. The horse did not respond to treatment by intravenous administration of dexamethasone, hypertonic or isotonic saline. The status deteriorated and the horse was euthanised 4 h after the end of anaesthesia. The main pathological findings were haemorrhage, oedema and malacia of L5-L6 spinal cord segments and cauda equina. Histological examination of the spinal cord revealed haemorrhage and areas of necrosis predominantly in the grey matter of L5 and L6 segments. Impairment of spinal cord perfusion due to haemodynamic changes associated with dorsal recumbency and general anaesthesia is presumed. Predisposition factors could include young age, dorsal recumbency and high weight.

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Out of the total number of 434 horses that underwent colic surgery, small intestine was operated in 195 (44.9%) patients, caecum in 10 (2.3%) horses, large colon surgery was performed in 196 (45.2%) cases and small colon surgery in 14 (3.2%) horses. In 12 patients (2.8%) two different parts of the gastrointestinal tract were affected simultaneously, one horse suffered from peritonitis, torsion of the uterus developed in two mares and three animals had negative surgical findings. Of 434 horses, 371 (85.5%) survived. After small intestinal surgery, 159 patients (81.5%) recovered from anaesthesia and were discharged home as well as seven horses (70%) after caecal surgery, 175 horses (89.3%) after large colon surgery and 14 horses (100%) following small colon surgery. 75 out of 103 horses (72.8%) were discharged home after the small intestinal resection and 89 of 98 horses (90.8%) with small intestinal problems where no resection was needed. In total, 43 of the patients that underwent one surgery did not survive the immediate postoperative period. The most frequent lethal complications in horses following the small intestinal surgery included peritonitis (five horses) and paralytic ileus (four horses) and in horses with large colon problems it was typhlocolitis (six cases). Relaparotomy was indicated in 41 of 434 horses (9.4%) that recovered from colic surgery. 21 out of the 41 (51.2%) relaparotomised colic patients were released from the clinic. All successfully repeated surgeries were carried out to overcome primary small intestine ileus problems, and in 14 of these cases (66.7%) resection and anastomosis were performed. The most common finding, diagnosed in 9 of 21 reoperated horses, was paralytic ileus. Of 20 relaparotomised horses that did not survive, three animals were lost after the introduction of anaesthesia, nine horses were euthanised after the abdominal cavity revision, one horse did not recover after the surgical procedure and seven horses did not survive the postoperative period. In 15 of 20 dead horses, the cause of the first surgical intervention was small intestinal ileus, in other four horses there was a large colon problem and in the last patient, it was a stomach disease. In 13 of 15 (86.7%) horses with small intestinal problems and in three of four (75%) patients with large colon disease, either resection or bypass was performed. In the remaining four non-surviving horses of 20 relaparotomised ones, peritonitis and/or adhesion formation was diagnosed at the second surgery, in three horses anastomosis complications were the main problem. Peritonitis or paralytic ileus led to death or euthanasia in four of seven horses that recovered after relaparotomy.

ABSTRACT:This research aimed to determine the effect of aerosolized salbutamol administration on systemic and pulmonary hemodynamic, pulmonary mechanics and oxygen balance in healthy horses during general anaesthesia. Six healthy Thoroughbreds (body weight range 471-587 kg) underwent two general anaesthesias in dorsal recumbency with and without aerosolized salbutamol administration in randomized order with a one month washout period. The anaesthesia was induced by 1.1 mg/kg of xylazine, 0.02 mg/kg of diazepam and 2.2 mg/kg of ketamine, maintained with isoflurane in oxygen and air and horses were mechanically ventilated. Measurement of arterial and pulmonary arterial blood pressures, cardiac output and arterial and mixed venous blood gas analysis was carried out. Spirometry was performed using a Horse-lite. After achieving a steady state, baseline (T 0 ) values of cardiac output, systemic and pulmonary arterial blood pressures, heart rate, dynamic compliance, airway resistance and arterial and mixed venous blood gas values and pH were recorded in both groups. In the S-group (salbutamol), 2 µg/kg of aerosolized salbutamol were administered synchronously with inspirium into the tracheal tube. In both groups data were recorded at 15, 30, 45 and 60 min (T 15 , T 30 , T 45 , T 60 ) after the baseline. PaO 2 /FiO 2 ratio, oxygen consumption (VO 2 ), oxygen delivery (DO 2 ), pulmonary shunt values were calculated. Data were tested for normality and compared within each group: T 0 value with T 15 , T 30 , T 45 , T 60 values using Wilcoxon's test with Bonferoni correction (significance level 0.0125). For each time point, comparisons were made between the S-and C-groups (control) using Wilcoxon's test. In the S-group, there was a significant increase in values (mean ± SD) of cardiac output (l/min), T 0 (38 ± 7), a peak at T 15 (64 ± 25.5), significantly higher values persisted throughout the period of anaesthesia; heart rate (beats/min), T 0 (32 ± 2), T 15 (40 ± 6), T 30 (38 ± 5); DO 2 (l/min), T 0 (5.8 ± 0.8), a peak at T 15 (9.6 ± 3.2), significantly higher values persisted until the end of anaesthesia and VO 2 (l/min), T 0 (1.1 ± 0.5), T 30 (1.6 ± 0.7) and T 45 (1.8 ± 0.5). In the C-group, there was a significant decrease in values of PaO 2 /FiO 2 ratio from T 0 (176 ± 67) to a minimum at T 60 (114 ± 36) and in DO 2 from T 0 (6 ± 2.3) to a minimum at T 60 (4.3 ± 1.2). A comparison of the S-and C-groups did not reveal any difference in the baseline data. Subsequently, significantly higher values of cardiac output, heart rate, DO 2 , and the PaO 2 /FiO 2 ratio were found in the S-group compared to the C-group. Pulmonary arterial blood pressure was significantly lower in the S-group. Aerosolized salbutamol administration in healthy horses during general anaesthesia caused hemodynamic changes which resulted in an elevation of oxygen delivery. It can have a positive effect on arterial oxygenation, but the effect varies between individuals.