Anesthesia for Video-Assisted Thoracoscopic Surgery (VATS)

Abstract

Thoracoscopy involves intentionally creating a pneumothorax and then introducing an instrument through the chest wall to visualize the intrathoracic structures. Recent application of video cameras to thoracoscopes for high-definition magnified viewing coupled with the development of sophisticated surgical instruments and stapling devices has greatly expanded the endoscopist’s ability to do increasingly more complex procedures by thoracoscopy. Recent advances include uniportal surgical techniques and preoperative CT-guided micro-coil localization of very small lesions.

Clinical Case Discussion

A 67-year-old male with a right upper lobe non-small cell lung tumor is scheduled for VATS right upper lobectomy (see Fig. 24.12). He has COPD, preoperative FEV1 is 57% predicted, and DLCO is 60%. No other comorbidities. After intravenous induction of anesthesia, he is intubated with a left double-lumen tube. After turning the patient to the left lateral position and confirming the position of the double-lumen tube with fiber-optic bronchoscopy, one-lung anesthesia is begun with sevoflurane (1MAC) and a FiO2 of 1.0, pressure-control ventilation, tidal volume 6 ml/kg, and resp. rate 12/min. When the surgeon places the VATS camera in the right chest, the lung is not completely collapsed. What can be done to improve lung collapse?

Fig. 24.12

Chest X-ray of a patient with a right upper lobe non-small cell lung cancer scheduled for VATS lobectomy. The patient has moderate COPD as evidenced by the hyperinflation of the lungs and the narrow cardiac silhouette

Answer: The position of the double-lumen tube should be reconfirmed with bronchoscopy. The adequacy of lung isolation should be confirmed by verifying that the inspired and expired tidal volumes of the left lung match using side-stream spirometry (the expired tidal volume is often a small percentage lower than the inspired volume due to the greater uptake of oxygen than the production of CO2). The use of FiO2 1.0 to the operative lung prior to the initiation of one-lung ventilation will increase the rate of lung collapse, and a low suction (20 cmH20) applied to the non-ventilated lung will also speed collapse (see text).

With the onset of one-lung ventilation, the arterial oxygen saturation begins to slowly decrease. All other vital signs are stable: HR 78, BP 130/82, and PetCO2 32 mmHg. After 20 min of surgery, the SpO2 has fallen to 89% and continues to decline. What is the most appropriate next step?

Answer: After reconfirming the FiO2 and the correct position of the double-lumen tube with bronchoscopy, a recruitment maneuver of the left lung is performed, and PEEP 5cmH2O is added to the left lung. In spite of these therapies, the SpO2 continues to fall and is now 87%. The anesthesiologist suggests applying CPAP to the operative left lung. The surgeon is adamant that he/she will not be able to complete the operation as a VATS procedure if CPAP is necessary and will have to convert to an open thoracotomy.

Is there any other therapy that can improve oxygenation and will not interfere with surgical exposure?

Answer: Guided insufflation of oxygen at 5 L/min into the basilar segments of the right lower lobe is performed for 30 sec via the suction channel of the fiber-optic bronchoscope, while the surgeon monitors the insufflation using the VATS camera (see Chap. 6, Fig. 6.10). After partial re-inflation of the anterior and lateral basal segments of the right lower lobe, the SpO2 increases to 93% and surgery continues. The bronchoscopic segmental insufflation needed to be repeated once again 20 min later when the SpO2 fell to <90%. Surgery was completed without complication or conversion to open thoracotomy. Management of hypoxemia during VATS procedures is outlined in Table 24.4.

Table 24.4 Management of hypoxemia during VATS