Objective—To determine whether sublingual detomidine gel administration to horses would be effective in providing an appropriate degree of sedation and restraint to facilitate completion of veterinary and husbandry procedures under field conditions.
Animals—270 client-owned horses known to require sedation or strong restraint to enable veterinary and husbandry procedures to be performed.
Procedures—Horses randomly received a single dose of detomidine gel (0.04 mg/kg [0.018 mg/lb]) or placebo gel administered sublingually. Horses were sedated to facilitate cleaning the prepuce, cutting of hair with electric clippers, hoof trimming or application of shoes, manual dental floating (ie, rasping or filing of the teeth to remove irregularities), nasogastric passage of a stomach tube or endoscope, and radiography. The primary determinant of efficacy was an assessment by a veterinarian on the ability or inability to successfully conduct the procedure.
Results—171 horses met all the study protocol criteria. One hundred twenty-nine horses were treated with detomidine. The procedure was completed successfully for 76% (98/129) of the detomidine-treated horses, while the procedure was completed successfully for only 7% (3/42) of the placebo-treated horses. The percentage of horses in which the procedure was successfully completed was significantly different between detomidine-treated horses and placebo-treated horses. No serious adverse effects were reported.
Conclusions and Clinical Relevance—Detomidine gel administered to horses sublingually at a dose of 0.04 mg/kg provided an appropriate degree of sedation and restraint to facilitate completion of veterinary and husbandry procedures in horses known to require sedation for such procedures.
Objective—To determine whether inhaled nitric oxide
(NO) prevents pulmonary hypertension and improves
oxygenation after IV administration of a bolus of
dexmedetomidine in anesthetized sheep.
Animals—6 healthy adult sheep.
Procedure—In a crossover study, sevoflurane-anesthetized
sheep received dexmedetomidine (2 µg/kg,
IV) without NO (DEX treatment) or with inhaled NO
(DEX-NO treatment). Cardiopulmonary variables,
including respiratory mechanics, were measured
before and for 120 minutes after bolus injection of
Results—Dexmedetomidine induced a transient
decrease in heart rate and cardiac output. A short-lived
increase in mean arterial pressure (MAP) and
systemic vascular resistance (SVR) was followed by a
significant decrease in MAP and SVR for 90 minutes.
Mean pulmonary arterial pressure (MPAP) and pulmonary
vascular resistance increased transiently after
dexmedetomidine injection. The PaO2 was significantly
decreased 3 minutes after injection and reached a
minimum of (mean ± SEM) 13.3 ± 7.8 kPa 10 minutes
after injection. The decrease in PaO2 was accompanied
by a sudden and prolonged decrease in dynamic
compliance and a significant increase in airway resistance,
shunt fraction, and alveolar dead space. Peak
changes in MPAP did not differ between the 2 treatments.
For the DEX-NO treatment, PaO2 was significantly
lower and the shunt fraction significantly higher
than for the DEX treatment.
Conclusions and Clinical Relevance—Inhalation of
NO did not prevent increases in pulmonary arterial
pressures induced by IV administration of
dexmedetomidine. Preemptive inhalation of NO
intensified oxygenation impairment, probably through
increases in intrapulmonary shunting. (Am J Vet Res