Lateral Position Test: A Simple, Inexpensive, Yet Accurate Method of Studying the Separate Functions of the Lungs

¹ Chief, Pulmonary Function Laboratory, Fitzsimons General Hospital, Denver, Colorado
² Chief, Anesthesia and Operative Service, Fitzsimons General Hospital, Denver, Colorado

We performed the lateral position test on 16 patients and compared the results with those of bronchospirometry. The lateral position test is based on the observed increase in functional residual capacity (FRC) when a subject moves from the supine to the lateral decubitus position. The greater increase in FRC occurs when the better functioning lung lies uppermost. The standard deviation limits of the linear least squares regression lines between the lateral position test on the one hand and relative oxygen consumption and minute ventilation on the other were ± 5.35 percent and ± 6.31 percent respectively. Therefore, we conclude that the lateral position test accurately reflects the relative distribution of oxygen uptake and minute ventilation of the right and left lung.