Comparison of Differential Lung Ventilation and CPAP during One Lung Ventilation for Video Assisted Lung Surgery; Preliminary Results

Background: One Lung Ventilation (OLV) is a ventilation technique used during lung resection operation in order to facilitate optimal surgical condition. OLV may result in hypoxemia due to the shunt created. Several techniques are used to overcome that hypoxemia, one is continuous positive airway pressure (CPAP) to the non-dependent lung. Another technique is ventilating the non-dependent lung with minimal volume, thus creating differential ventilation. This study was design to compare the efficacy of CPAP to that of differential ventilation to the non-dependent lung during video assisted thoracoscopic surgery (VATS).

Patients and Method: This is a prospective study of 30 adult patients undergoing VATS lobectomy. Each patient was ventilated in 4 modes: bilateral lung ventilation, OLV, OLV+CPAP and OLV+differential ventilation. Fifteen patients are ventilated with CPAP first and differential ventilation later, and the other 15 patients were ventilated with differential ventilation first and CPAP later. Ten minutes separated each mode. We measure the patient`s oxygen partial pressure in arterial blood gas during each mode of ventilation. The surgeons, who are blinded to the ventilation technique, are asked to assess the surgical conditions at each stage.

Results: In preliminary analysis of 17 patients we found the differential ventilation to be significantly superior to CPAP during OLV by improving blood oxygen partial pressure. No significant difference was found between the two regarding the surgeons` assessment of the surgical field condition.

Conclusions: Differential lung ventilation improves oxygenation of patients during OLV. It is superior to CPAP and may be used where CPAP failed.