American journal of veterinary research
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To study behavioral and cardiopulmonary characteristics of horses recovering from inhalation anesthesia, 6 nonmedicated horses were anesthetized under laboratory conditions on 3 different days, with either halothane or isoflurane in O2. Anesthesia was maintained at constant dose (1.5 times the minimum alveolar concentration [MAC]) of halothane in O2 for 1 hour (H1), halothane in O2 for 3 hours (H3), or isoflurane in O2 for 3 hours (I3). The order of exposure was set up as a pair of Latin squares to account for horse and trial effects. ⋯ For all groups, arterial blood pressure increased throughout the early recovery period and heart rate remained constant. Preanesthesia temperament of horses and the inhalation agent used did not influence the time of the early recovery events (movement of eyelids, ears, head, and limbs), except for head lift. For events that occurred at anesthetic end-tidal percentage < 0.20, or when horses were awake, temperament was the only factor that significantly influenced the nature of the recovery (chewing P = 0.04, extubation P = 0.001, first stand attempt P = 0.008, and standing P = 0.005).(ABSTRACT TRUNCATED AT 400 WORDS)
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A rebreathing method for measurement of pulmonary diffusing capacity for carbon monoxide (DLCO) and functional residual capacity (FRC) was evaluated in conscious horses. Horses were manually ventilated through an endotracheal tube, using a custom-made syringe filled with a gas mixture containing 18-carbon monoxide (18CO) and helium (He). ⋯ In 11 Thoroughbreds, mean (+/- SD) DLCO was 330.3 +/- 56.9 ml.min-1 x mm of Hg-1, and FRC was 20.21 +/- 3.35 L. Body weight normalization yielded mean (+/- SD) values of 0.652 +/- 0.114 ml.min-1 x mm of Hg-1 x kg-1 for DLCO, and 39.9 +/- 6.4 ml.kg-1 for FRC.
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Cardiovascular effects of IV administered ketamine (10 mg/kg) and midazolam (0.5 mg/kg) were determined in 12 healthy isoflurane-anesthetized (1.7% end-tidal concentration) dogs. Six dogs received a ketamine-midazolam combination (K-M) as a bolus over 30 seconds and 6 dogs received K-M as an infusion over 15 minutes. Ketamine-midazolam combination as a bolus and an infusion caused early significant (P < 0.05) reductions in mean systemic blood pressure, cardiac index, and stroke index, which returned to baseline values near the end of the study. ⋯ Four dogs were maintained with 1.7% end-tidal isoflurane to determine temporal effects of isoflurane; these dogs did not receive K-M. Increases in heart rate, cardiac index, stroke index, and left and right ventricular stroke work indexes were significant (P < 0.05) at various sample collection intervals, particularly during the later stages of the study. Isoflurane anesthesia effectively blocked the cardiostimulatory properties of K-M.(ABSTRACT TRUNCATED AT 250 WORDS)