Comparison of three methods of temperature measurement in hypothermic, euthermic, and hyperthermic dogs.

OBJECTIVE: To assess the reliability and accuracy of a predictive rectal thermometer, an infrared auricular thermometer designed for veterinary use, and a subcutaneous temperature-sensing microchip for measurement of core body temperature over various temperature conditions in dogs. DESIGN: Prospective study. ANIMALS: 8 purpose-bred dogs. PROCEDURES: A minimum of 7 days prior to study commencement, a subcutaneous temperature-sensing microchip was implanted in 1 of 3 locations (interscapular, lateral aspect of shoulder, or sacral region) in each dog. For comparison with temperatures measured via rectal thermometer, infrared auricular thermometer, and microchip, core body temperature was measured via a thermistor-tipped pulmonary artery (TTPA) catheter. Hypothermia was induced during anesthesia at the time of TTPA catheter placement; on 3 occasions after placement of the catheter, hyperthermia was induced via administration of a low dose of endotoxin. Near-simultaneous duplicate temperature measurements were recorded from the TTPA catheter, the rectal thermometer, auricular thermometer, and subcutaneous microchips during hypothermia, euthermia, and hyperthermia. Reliability (variability) of temperature measurement for each device and agreement between each device measurement and core body temperature were assessed. RESULTS: Variability between duplicate near-simultaneous temperature measurements was greatest for the auricular thermometer and least for the TTPA catheter. Measurements obtained by use of the rectal thermometer were in closest agreement with core body temperature; for all other devices, temperature readings typically underestimated core body temperature. CONCLUSIONS AND CLINICAL RELEVANCE: Among the 3 methods of temperature measurement, rectal thermometry provided the most accurate estimation of core body temperature in dogs.

Pilot study on the effect of subcutaneous administration of lactated Ringer's solution on biochemistry parameters in healthy euvolemic cats.

Subcutaneous fluid administration is a commonly used therapy in veterinary practice. Its safety and efficacy have been demonstrated in human clinical studies, but have only rarely been discussed in the veterinary literature. This prospective observational study was performed to evaluate changes during a 24 h period in serum biochemistries associated with administration of lactated Ringer's solution subcutaneously to healthy cats. Lactated Ringer's solution was administered subcutaneously once to ten healthy, euvolemic cats at a dose of 22 mL kg-1. Blood biochemistry analytes were sampled at baseline and at serial time points for a total of 24 h. Changes in biochemical analytes at each time point were compared to baseline and evaluated for statistical significance. Serum blood urea nitrogen (BUN) was significantly less than baseline at 4, 6, 12, 18, and 24 h post-infusion. Serum creatinine was significantly less than baseline at 2, 4 and 6 h. Packed cell volume (PCV) was significantly less than baseline at 6, 12, 18, and 24 h. Total plasma proteins were significantly less than baseline at all time points. Serum electrolytes did not change from baseline at any time point. Urine specific gravity was significantly increased from baseline only at 6 h post-Lactated Ringer's solution (LRS) administration. Subcutaneous administration of lactated Ringer's solution appears to result in haemodilution with minimal change to serum electrolyte concentrations in clinically normal, euvolemic cats.