Korean J Anesthesiol.  2012 Mar;62(3):256-259. 10.4097/kjae.2012.62.3.256.

The effects of incremental continuous positive airway pressure on arterial oxygenation and pulmonary shunt during one-lung ventilation

• Kim YD
• Ko S
• Kim D
• Lim H
• Lee JH
• Kim MH

• KMID: 2299353
• DOI: http://doi.org/10.4097/kjae.2012.62.3.256

Abstract

BACKGROUND
Although one lung ventilation (OLV) is frequently used for facilitating thoracic surgical procedures, arterial hypoxemia can occur while using one lung anesthesia. Continuous positive airway pressure (CPAP) in 5 or 10 cmH2O to the non-ventilating lung is commonly recommended to prevent hypoxemia. We evaluated the effects of incremental CPAP to the non-ventilating lung on arterial oxygenation and pulmonary shunt without obstruction of the surgical field during OLV.
METHODS
Twenty patients that were scheduled for one lung anesthesia were included in this study. Systemic and pulmonary hemodynamic data and blood gas analysis was recorded every fifteen minutes according to the patient's positions and CPAP levels. CPAP was applied from 0 cmH2O by 3 cmH2O increments until a surgeon notifies that the surgical field was obstructed by the expanded lung. Following that, pulmonary shunt fraction (QS/QT) was calculated.
RESULTS
There were no significant differences of QS/QT between supine and lateral positions with two lung ventilation (TLV). OLV significantly decreased arterial oxygen partial pressure (PaO2) and increased QS/QT compared to TLV. PaO2 and QS/QT significantly improved at 6 and 9 cmH2O of CPAP compared to 0 cmH2O. However, there were no significant differences of PaO2 and QS/QT between 6 and 9 cmH2O CPAP. In 18 patients (90%), surgical fields were obstructed at 9 cmH2O CPAP.
CONCLUSIONS
This study suggests that 6 cmH2O CPAP effectively improved arterial oxygenation without interference of the surgical field during OLV when CPAP was applied from 0 cmH2O in 3 cmH2O increments.

Keyword

Continuous positive airway pressure; One lung ventilation; Oxygenation; Surgical field

MeSH Terms

Anesthesia
Anoxia
Blood Gas Analysis
Continuous Positive Airway Pressure
Hemodynamics
Humans
Lung
One-Lung Ventilation
Oxygen
Partial Pressure
Thoracic Surgical Procedures
Ventilation
Oxygen