Improved Oxygenation During Thoracotomy with Selective PEEP to the Dependent Lung

Abstract

In 22 patients during thoracotomy in the lateral position, the effects of selective positive end-expiratory pressure (PEEP) to the dependent lung while simultaneously ventilating the non-dependent lung at zero end-expiratory pressure (ZEEP) on (1) inspired O2 concentration required to maintain adequate Pao2 during thoractomy and 2) alveolar-arterial oxygen difference (AaO2D) while breathing 100 percent O2 at the end of thoractomy were examined and compared to ventilation of both lungs at ZEEP, Selective PEEP to the dependent lung resulted in adequate PaO2 with a lower inspired O2 concentration (44 +/- SD 6% versus 70 +/- SD 21%), and a smaller AsO2D while breathing 100 percent O2 189 +/- SD 31 versus 342 +/- SD 69 torr) at the end of thoracotomy.

Determination of the side-separated pulmonary right-to-left shunt volume

“…From the test we gained interesting new insights. In agreement with Brown, et al (9), THT in Two-LV (PEEP +6 cmH2O) does not deteriorate oxygenation (PaO2 : 473.5 ! 69.4 vs. 469.9 !…”

Effect of Positive End‐Expiratory Pressure on Oxygen Delivery During 1‐Lung Ventilation for Thoracoscopy in Normal Dogs

“…Methods to improve oxygenation during 1‐lung ventilation and thoracoscopy need to be evaluated to minimize anesthetic risk to the patient. Such methods may include varying tidal volume, 20 continuous positive airway pressure (CPAP) to the nonventilated lung, 17,22 and the application of positive end‐expiratory pressure (PEEP) to the ventilated lung 18,28–31 …”

“…It has been shown that the effect of PEEP should be determined and optimized by measuring DO 2 52 . DO 2 to peripheral tissues is determined by both CO and arterial oxygen content (CaO 2 ) 16,17,28–30,53 . If PEEP induces a significant reduction in CO that outweighs the gain in CaO 2 , the net results will be adverse for the patient.…”

“…Such methods may include varying tidal volume, 20 continuous positive airway pressure (CPAP) to the nonventilated lung, 17,22 and the application of positive end-expiratory pressure (PEEP) to the ventilated lung. 18,[28][29][30][31] PEEP has been used to treat different respiratory conditions or during surgery to improve arterial oxygen saturation. 26,28,32,33 PEEP decreases ventilation-perfusion (V/Q) mismatch by increasing the distention of poorly ventilated alveoli and by recruitment of collapsed alveoli.…”

The effect of positive end expiratory pressure on the respiratory profile during one‐lung ventilation for thoracotomy*

“…Applying PEEP would help to splint the alveoli throughout the respiratory cycle and thus improve oxygenation. However, several studies on the effects of PEEP during OLV produced conflicting evidence, some showing improvement [12][13][14][15][16] and others no benefit or worsening of P a O 2 [17][18][19][20][21].…”