Noninvasive ventilation in cats.
OBJECTIVE
The primary objective of this study was to assess the feasibility of noninvasive mechanical ventilation (NIV) in cats. The secondary objective was to determine whether cardiovascular parameters and anesthetic drug requirements associated with noninvasive ventilation differ from those associated with invasive ventilation.


METHODS
Randomized, cross-over design.


METHODS
A research laboratory in a veterinary teaching hospital.


METHODS
Eight healthy adult cats, 3 intact females and 5 intact males, weighing between 3 and 6 kg, were used.


METHODS
Each cat was randomly assigned to NIV via nasal mask, or invasive ventilation using an endotracheal tube. Mechanical ventilation was performed for 6 hours. Anesthesia was provided using continuous infusions of propofol and butorphanol. After a minimum 9-day washout period, the procedure was repeated using the alternate ventilation interface.


RESULTS
Cardiovascular parameters (heart rate, rectal temperature, direct arterial blood pressure), arterial blood gases, drug requirements, sedation score, and ventilation parameters, were monitored throughout the procedures. These values were evaluated using ANCOVA for repeated measures. All cats were effectively ventilated using NIV. There were no significant differences in cardiovascular parameters, drug requirements, or sedation scores between groups. Although PaCO(2) values did not differ, PaO(2) values were significantly higher in the invasively ventilated group. Inspiratory tidal volumes were similar between groups, whereas expiratory tidal volumes were significantly lower in the NIV group. Inspiratory pressures were significantly higher in the NIV group. Respiratory frequency was significantly higher in the invasively ventilated group.


CONCLUSIONS
NIV of cats is possible. However, currently it does not confer any cardiovascular benefit over invasive ventilation and drug requirements are similar. Use of a correctly fitted mask is essential for successful NIV as air leaks account for the observed discrepancy between inspiratory and expiratory volumes. Further investigation into this modality is warranted.
Brown
Judy E
JE
Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada. jebrown@uoguelph.ca
Bersenas
Alexa M E
AM
Mathews
Karol A
KA
Kerr
Carolyn L
CL
D000818:Animals; D002415:Cats; D018592:Cross-Over Studies; D005260:Female; D007442:Intubation, Intratracheal / Q000662:veterinary; D008297:Male; D011659:Pulmonary Gas Exchange; D012123:Pulmonary Ventilation; D012121:Respiration, Artificial / Q000295:instrumentation / Q000379:methods / Q000662:veterinary*