Sequential Changes of Arterial Oxygen Tension in the Supine Position During One-Lung Ventilation

Abstract

Close observation and prompt counteractions including termination of one-lung ventilation (OLV) are crucial for patients under OLV in the supine position, because life-threatening hypoxemia frequently occurs approximately 10 min after starting OLV, even under 100% oxygen inhalation. The left semilateral decubitus position was as effective as the left lateral decubitus position in avoiding life-threatening hypoxemia during OLV.

Gradient of bronchial end-tidal CO2 during two-lung ventilation in lateral decubitus position is predictive of oxygenation disorder during subsequent one-lung ventilation

“…The amount of pulmonary perfusion in LP is larger in the dependent lung than in the nondependent lung. Therefore Pa O 2 during OLV is kept comparatively higher in LP than in SP [13].…”

Pressure-controlled versus volume-controlled ventilation during one-lung ventilation in the prone position for robot-assisted esophagectomy

“…The suggested mechanisms of improving oxygenation during the prone position are alveolar recruitment, improved V/Q matching, and reduced parenchymal lung stress and lung strain through the elimination of compression of the lungs by the heart and redistribution of perfusion and ventilation, which provide the rationale for ventilating patients with acute respiratory distress disease (ARDS) in the prone position [16][17][18][19][20]. However, the development of hypoxemia during OLV depends mainly on the magnitude of the Qs/Qt of the nonventilated lung and the matching of the V/Q in the ventilated lung, in which gravity plays a pivotal role [4,5]. In contrast to the lateral decubitus position, gravity induced preferential redistribution of the pulmonary blood flow to the dependent ventilated lung resulting in improved V/Q is absent during OLV in the prone position, similar to the supine position, resulting in more frequent development of dangerous hypoxemia [4].…”

“…However, the development of hypoxemia during OLV depends mainly on the magnitude of the Qs/Qt of the nonventilated lung and the matching of the V/Q in the ventilated lung, in which gravity plays a pivotal role [4,5]. In contrast to the lateral decubitus position, gravity induced preferential redistribution of the pulmonary blood flow to the dependent ventilated lung resulting in improved V/Q is absent during OLV in the prone position, similar to the supine position, resulting in more frequent development of dangerous hypoxemia [4]. In addition, MIE requires the exposure of the right external thorax, necessitating the use of longitudinal bolsters instead of the more sophisticated chest frames for prone positioning.…”

“…Surgical positions considerably influence the deterioration speed and the nadir value of arterial oxygen tension (PaO 2 ) after the start of OLV [4]. The development of hypoxemia during OLV depends mainly on the intrapulmonary shunt (Qs/Qt) through the nonventilated lung and matching of the ratio of ventilation and perfusion (V/Q) in the ventilated lung.…”

“…The development of hypoxemia during OLV depends mainly on the intrapulmonary shunt (Qs/Qt) through the nonventilated lung and matching of the ratio of ventilation and perfusion (V/Q) in the ventilated lung. In contrast to the lateral decubitus position, OLV in the prone position is devoid of the beneficial effect of gravity on preferential redistribution of the pulmonary blood flow to the dependent areas of a lung, possibly resulting in increased V/Q mismatch [4,5]. Also, the prone position is frequently associated with decreased respiratory compliance and increased peak airway pressure in anesthetized and paralyzed patients when not assuring free abdominal and chest movements, which is further aggravated by CO 2 insufflation [6,7].…”