Assessment of Oxygen Delivery as an Early Predictor of Postoperative Pulmonary Complications During One-lung Pulmonary Ventilation in Thoracic Surgery. A Pilot Study

One-lung ventilation (OLV) is necessary to facilitate surgical exposure in thoracic surgery. OLV can lead to hypoxemia due to the collapse of the non-dependent lung with potentially increased atelectasis in the dependent lung. Hypoxemia, the low oxygen level in the blood, during OLV can be detected by a decrease in arterial hemoglobin oxygen saturation (SaO2) measured by pulse oximetry (SpO2%). Although the incidence of hypoxemia during OLV is currently considered less than 4%, SaO2 is not well correlated to the oxygen supply to the tissues, determined by oxygen delivery (DO2), thus normal values of SaO2 can be associated with abnormal values of DO2 and on the contrary, hypoxemic values of SaO2 can be associated with normal values of DO2. Hypoxemia in patients with cardiovascular, cerebrovascular and/or pulmonary disease leads to an increased risk of complications related to low oxygen supply.

Postoperative pulmonary complications (POPCs) can lead to increased perioperative morbidity and mortality, increased incidence of admission to an intensive care unit, prolonged hospital stay and increased medical cost.

To the best of our knowledge, there are no studies in thoracic surgery, including esophagectomies, where intraoperative Oxygen Delivery (DO2) or DO2 index (DO2i) is used as a strategy for early detection of POPCs. There are also no studies that have determined the critical level of DO2 and DO2i or Percentage of Oxygen Extraction (O2ER) and Percentage of Oxygen Extraction index (O2ERi) in thoracic surgery associated with POPCs.

The aim of this study is to determine if the use of DO2 and DO2i as a continuous non-invasive monitor of oxygen supply to the tissues during OLV, may help us determine the critical DO2 and DO2i to predict POPCs.