Effect of aerosolized albuterol sulfate on resting energy expenditure determined by use of open-flow indirect calorimetry in horses with recurrent airway obstruction.
OBJECTIVE
To evaluate effects of sedation on stability of resistance of the respiratory system (RRS) and measures of resting energy expenditure (REE) by use of open-flow indirect calorimetry (IC) and treatment with aerosolized albuterol on REE in horses with recurrent airway obstruction (RAO).


METHODS
9 clinically normal horses and 8 horses with RAO.


METHODS
In phase 1, RRS was measured by using forced oscillometry (FOT) in 5 clinically normal horses before and after sedation with xylazine. In phase 2, REE was measured in 4 clinically normal horses between 20 and 25 minutes and again 35 to 40 minutes after sedation with xylazine. In phase 3, IC was performed between 20 and 25 minutes and FOT was performed between 30 and 35 minutes after xylazine administration in 8 horses with RAO; after administration of 450 microg of albuterol, IC and FOT were repeated.


RESULTS
In phase 1, RRS values were significantly lower 5 and 10 minutes after sedation. In phase 2, diminishing sedation did not significantly affect REE. In phase 3, there was a significant decrease in mean RRS (1.15 +/- 0.25 vs 0.84 +/- 0.14 cm H20/L/s) and REE (30.68 +/- 17.89 vs 27.46 = 16.54 kcal/kg/d) after albuterol administration.


CONCLUSIONS
FOT and IC are useful in obtaining repeatable measurements of RRS and REE, respectively, in sedated horses. Concurrent bronchodilation and decreased REE after albuterol administration suggest that increased work of breathing as a result of airway obstruction may contribute to increased energy demands in horses with RAO.
Mazan
Melissa R
MR
Lung Function Laboratory, Department of Clinical Sciences, School of Veterinary Medicine, Tufts University, North Grafton, MA 01536, USA.
Hoffman
Andrew M
AM
Kuehn
Heike
H
Deveney
Edward F
EF
D000336:Aerosols / Q000494:pharmacology / Q000627:therapeutic use; D000420:Albuterol / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D001481:Basal Metabolism / Q000187:drug effects*; D002153:Calorimetry, Indirect / Q000662:veterinary*; D006734:Horse Diseases / Q000188:drug therapy / Q000503:physiopathology; D006736:Horses / Q000502:physiology*; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D008173:Lung Diseases, Obstructive / Q000188:drug therapy / Q000503:physiopathology* / Q000662:veterinary*; D009991:Oscillometry / Q000662:veterinary; D012143:Respiratory Physiological Phenomena / Q000187:drug effects; D012137:Respiratory System / Q000187:drug effects / Q000503:physiopathology; D014991:Xylazine / Q000494:pharmacology
D000336:Aerosols; D006993:Hypnotics and Sedatives; D014991:Xylazine; D000420:Albuterol