Effects of head-down tilt on intrapulmonary shunt fraction and oxygenation during one-lung ventilation in the lateral decubitus position

Choi, Yong Seon; Bang, Sou Ouk; Shim, Jae Kwang; Chung, Kyung Young; Kwak, Young Lan; Hong, Yong Woo

doi:10.1016/j.jtcvs.2007.05.018

« Previous Next »The Journal of Thoracic and Cardiovascular Surgery
Volume 134, Issue 3 , Pages 613-618, September 2007

Effects of head-down tilt on intrapulmonary shunt fraction and oxygenation during one-lung ventilation in the lateral decubitus position

Yong Seon Choi, MD
- Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, Seoul, South Korea
Sou Ouk Bang, MD
- Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, Seoul, South Korea
- Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, South Korea
Jae Kwang Shim, MD
- Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, Seoul, South Korea
- Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, South Korea
Kyung Young Chung, MD, PhD
- Department of Thoracic and Cardiovascular Surgery, Yonsei University College of Medicine, Seoul, South Korea.
Young Lan Kwak, MD, PhD
- Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, Seoul, South Korea
- Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, South Korea
- Yonsei Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul, South Korea
Yong Woo Hong, MD, PhD
- Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, Seoul, South Korea
- Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, South Korea
- Yonsei Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul, South Korea
- Address for reprints: Yong Woo Hong, MD, PhD, Department of Anesthesiology and Pain Medicine and Anesthesia and Pain Research Institute, Yonsei University College of Medicine, 134 Shinchon-Dong, Seodaemun-Ku, Seoul, South Korea, 120-725.

Received 24 February 2007; received in revised form 24 April 2007; accepted 11 May 2007.

Objective

During one-lung ventilation, surgical positions significantly affect deterioration of oxygenation, and the lateral decubitus position is superior in preventing dangerous hypoxemia compared with the supine position. However, additional head-down tilt causes more compression of the dependent ventilated lung by the abdominal contents and may result in dangerous hypoxemia, as occurs in the supine position. Therefore, we evaluated the effect of head-down tilt on intrapulmonary shunt and oxygenation during one-lung ventilation in the lateral decubitus position.

Methods

Thirty-four patients requiring one-lung ventilation were randomly allocated to the control group (n = 17) or the head-down tilt group (n = 17). Hemodynamic and respiratory variables were measured 15 minutes after one-lung ventilation in the lateral decubitus position (baseline), 5 and 10 minutes after a 10-degree head-down tilt (T5 and T10, respectively), and 10 minutes after the patient was returned to a horizontal position (T20) in the head-down tilt group. Measurements were done at the same time points in the control group without head-down tilting.

Results

In the head-down tilt group, cardiac filling pressures were increased after head-down tilt without any changes in cardiac index. Percent change of shunt to baseline value was significantly increased at T10 and T20 in the head-down tilt group. Percent change of arterial oxygen tension to baseline value was significantly decreased at T5, T10, and T20 in the head-down tilt group, whereas it was decreased only at T20 in the control group.

Conclusion

Head-down tilt during one-lung ventilation in the lateral decubitus position caused a significant increase in shunt and a decrease in percent change of arterial oxygen tension, without causing dangerous hypoxemia.

CTSNet classification: 1, 9, 11

Abbreviations and Acronyms: A-aO₂, alveolar-arterial O₂ gradient, CI, cardiac index, CVP, central venous pressure, HPV, hypoxic pulmonary vasoconstriction, MAP, mean arterial pressure, OLV, one-lung ventilation, Pao₂, alveolar oxygen tension, Pao₂, arterial oxygen tension, PVRI, pulmonary vascular resistance index, VATS, video-assisted thoracoscopic surgery, V/Q, ventilation and perfusion