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A pilot study of left main bronchus pulse oximetry
Critical Care volume 9, Article number: P87 (2005)
To assess the feasibility and accuracy of measuring mixed venous oxygen saturation (SvO2) through the left main bronchus (SpO2trathea). The hypothesis that tracheal oximetry readings are not primarily derived from the tracheal mucosa was also tested. The pulmonary artery lies in close proximity to the bronchus, with nothing but some connective tissues in the interval, raising the possibility that an appropriately located and directed bronchial oximetry probe might be able to derive oximetry readings from the mixed venous system. The present study was undertaken to test the feasibility of measuring SvO2 through the left main bronchus (SpO2 trachea), and to compare SpO2 trachea with the Swan–Ganz catheter SpO2 (SvO2 catheter) and oxygen saturation from pulmonary artery samples (SvO2blood) in hemodynamically stable, well-oxygenated, anesthetized white swines. We also tested the hypothesis that bronchial oximetry readings are primarily derived from the pulmonary artery, not the tracheal mucosa. Furthermore, the stability and accuracy of SpO2 trachea was tested by correlating the oximetry readings with altered SvO2 or with internal environment instability.
Twenty hemodynamically stable, well-oxygenated, anesthetized white swine were studied. A Robertshaw double-lumen tracheal tube was directed toward the left main bronchus using a fibrobronchoscope. A single-use pediatric pulse oximeter was attached to the left lateral surface of the tube. SpO2trathea, Swan–Ganz catheter SpO2 (SvO2catheter) and oxygen saturation from pulmonary artery samples (SvO2blood) were taken with the intracuff pressure at 0–60 cmH2O. The intracuff pressure was then set at 60 cmH2O, and changes of SvO2 were induced using three different concentrations of inspiratory oxygen. The influence of the changes on SpO2trathea, SvO2catheter and SvO2blood was measured respectively at the same time.
SpO2trathea was the same as SvO2catheter and SvO2blood at an intracuff pressure of 10–60 cmH2O, but was less when the intracuff pressure was zero (P < 0.001 compared with SvO2catheter or SvO2blood) in hemodynamically stable states. The descending of SvO2followed with decreased inspiratory oxygen concentration. SpO2trachea agreed with SvO2catheter and SvO2blood at each concentration with significant correlation among them.
Left main bronchus SpO2 is feasible and provides similar readings to SvO2catheter and SvO2blood in hemodynamically stable or low saturation states. Tracheal oximetry readings are not primarily derived from the tracheal mucosa. The technique merits further evaluation.
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Wang, X., Zheng, Y., Tian, J. et al. A pilot study of left main bronchus pulse oximetry. Crit Care 9, P87 (2005). https://doi.org/10.1186/cc3150
- Pulmonary Artery
- Oxygen Saturation
- Pulse Oximetry
- Pulse Oximeter
- Tracheal Tube