Creating Working Space for Thoracoscopic Surgery

For certain thoracoscopic interventions such as pericardial window, thoracic duct ligation and lung biopsy, a pneumothorax that forms within the chest when the first cannula is placed and air is allowed to enter the pleural cavity, will provide adequate working space for the procedure to be completed safely. For these procedures, anesthesia concerns are similar to those for any “open” thoracotomy. Intravenous access should be established along with an indwelling arterial catheter for direct measurement of arterial blood pressure if possible. Variables monitored during the procedure will include heart rate and rhythm (on an ECG), oxygen saturation by pulse oximetry, end-tidal capnography and/or intermittent blood gas analysis and continuous arterial pressure. Positive pressure ventilation preferably with a mechanical ventilator will be mandatory for anesthetic maintenance as it is for open thoracic surgery.

To increase the working space in the thoracic cavity during more advanced thoracoscopic procedures there are several techniques that can be used. Intermittent ventilation can be used for shorter procedures and is variably tolerated by animals under anesthesia. Animals with normal pulmonary parenchyma may tolerate long breaks between ventilation, however those with cardiorespiratory disease may be less tolerant. Intermittent ventilation is generally frustrating for more complex procedures where intermittent inflation of lung fields obscures visualization making iatrogenic trauma to pulmonary parenchyma during instrument exchanges more likely and generally prolongs the procedure.  [...]