[Effects of oxygeninspired fractions and different ventilatory modalities on the age of dogs]

ABSTRACT

The objective was to evaluate different ventilatory modalities in dogs of different ages submitted to the inspired fraction of oxygen (FiO₂) of 40% and 100%. Thirty-six dogs from three age groups (GJ 0-5, GA 5-10 and GG 10-15 years) were used, without standardization of weight, gender, race and surgical procedure. They were premedicated with acepromazine and morphine (0.02 and 0.5mg/kg), induced to general anesthesia with propofol dose/effect, maintenance of the anesthetic plane with isoflurane in 1.3V% and oxygen supply according to FiO₂ established for the group. The animals were submitted to 4 different ventilation modalities, spontaneous ventilation (VS), volume-cycled ventilation (VCV), pressure-cycled ventilation (VCP) and pressure-cycled ventilation with PEEP (VCPP) and remained 30 minutes in each modality. The cardiovascular parameters remained stable for all FiO₂, ventilatory modalities and ages. Regarding ventilatory parameters, in FiO₂ and PaCO₂ of 45mmHg and 29% of shunt, in FiO2 100%, PaCO₂ of 43mmHg and 13% of shunt were observed. Regarding the different ages, adult and geriatric animals presented higher values of Shunt (26 and 22%) and PaCO₂ (44 and 46mmHg). It was concluded that the inspired fraction of 40% and the volume-cycled ventilatory modality were more efficient.

Keywords:
dogs; ventilatory modalities; oxygen inspired fraction; age; hemogasometry