Effects of head-up tilt on intrapulmonary shunt fraction and oxygenation during 1-lung ventilation in the lateral decubitus position
Received 2 March 2009; received in revised form 16 June 2009; accepted 16 July 2009. published online 26 August 2009.
Objective
Hypoxemia is a common problem of 1-lung ventilation. Arterial oxygenation progressively decreases after 1-lung ventilation. The surgical position influences the shunt and arterial oxygenation. Therefore we evaluated the effect of head-up tilt on intrapulmonary shunt and oxygenation during 1-lung ventilation in the lateral decubitus position.
Methods
Twenty patients requiring 1-lung ventilation were included in this study. During 1-lung ventilation, hemodynamic and respiratory variables were measured 15 minutes after horizontal positioning in the lateral decubitus position (baseline), 5 and 10 minutes after a 10-degree head-up tilt (T5 and T10, respectively), and 10 minutes after the patient was returned to a horizontal position (T20). Arterial and mixed venous blood analyses were performed at the same time points.
Results
Arterial oxygenation was increased, and shunt was decreased significantly during head-up tilt position in 1-lung ventilation. These changes were accompanied by decreases in the mean arterial pressure and cardiac filling pressures without significant changes in cardiac index.
Conclusions
Head-up tilt during 1-lung ventilation in the lateral decubitus position caused a significant decrease in shunt and an increase in arterial oxygenation that persisted after the patient was returned to the horizontal lateral decubitus position.
aDepartment of Anesthesiology and Pain Medicine, Ajou University of College of Medicine, Suwon, Korea
bDepartment of Thoracic and Cardiovascular Surgery, Ajou University of College of Medicine, Suwon, Korea
Address for reprints: Yong Woo Hong, MD, PhD, Department of Anesthesiology and Pain Medicine, Ajou University College of Medicine, San 5, Wonchon-dong, Yeongtong-gu, Suwon 443-721, Korea.
ABSTRACT