Effect of One-Lung Ventilation With or Without Low-Pressure Carbon Dioxide Insufflation on Cardiorespiratory Variables in Cats Undergoing Thoracoscopy

Objectives: To document a technique for one-lung ventilation (OLV) in cats and evaluate the effect of low-pressure carbon dioxide insufflation and OLV (OLV-CDI) on cardiorespiratory variables in cats. Study design: Prospective randomized study. Animals: Cats (n=6). Methods: General anesthesia was induced using a standardized anesthetic protocol. A thermodilution catheter was placed into the pulmonary artery using fluoroscopic guidance. Two 6mm thoracoscopic cannulae were placed at a subxiphoid and intercostal location, respectively, to allow direct observation of all lung lobes. OLV was induced using an endobronchial blocker, which was placed into the right and left main stem bronchi in randomized order using bronchoscopic guidance. Cardiorespiratory variables were measured at 5 and 30minutes after induction of OLV and subsequently at 5 and 30minutes after initiation of OLV-CDI at intra-thoracic pressures of 3mmHg. Results: Left-sided OLV was successful in 5 cats, right-sided OLV was successful in 2 cats, and neither was successful in 1 cat. No significant effects on hemodynamic variables or oxygen delivery were observed after right or left-sided OLV alone. Hemodynamic variables were also well-preserved after OLV-CDI; however, oxygen delivery was significantly lower after left OLV-CDI compared with right OLV-CDI, and in 2 cats, severe desaturation occurred after L-OLV-CDI before the 30minute time point. Conclusions: OLV can be used in cats for thoracoscopic interventions. Although right OLV-CDI was tolerated better than left OLV-CDI, the technique requires further investigation before it can be recommended for widespread clinical use.