Efeitos do modo ventilat???3rio sobre vari????veis hemogasom????tricas em equinos submetidos ???? mudan???§a de dec???obito durante a anestesia geral inalat???3ria com halotano

摘要

The effects of spontaneous (SV) and controlled ventilation (CV) were compared in horses undergoing changes in body position during anesthesia. Sixteen animals were equally distributed in two groups: SV and CV. All surgical procedures were commenced on left lateral recumbency (LLR) and 75 minutes later the animals were repositioned on right lateral recumbency (RLR). Arterial blood gas analyses were performed at 30 and 75 minutes after each recumbency (M1 and M2 for LLR and M3 and M4 for RLR). Hypercapnia (Pa CO 2 >45mm Hg), respiratory acidosis (p H <7.35), and significant decrease in Pa O 2 after 75min of change in body position (M4: 205.8?±124.7mm Hg) in comparison to Pa O 2 values before the change of position (M1: 271.8?±84.8mm Hg) were observed during SV. When compared to the SV group, CV resulted in significantly higher Pa O 2 levels (52 to 96% increase). It was concluded that the change in the body position in spontaneously ventilating halothane-anesthetized horses causes impairment in arterial oxygenation. The use of CV since the beginning of anesthesia prevents the respiratory acidosis and maintains arterial oxygen levels that are closer to values expected during the use of 100% O 2.