Does sitting posture in chronic obstructive pulmonary disease really matter? An analysis of 2 sitting postures and their effect [corrected] on pulmonary function.

Purpose: The purpose of this study was to investigate changes that occur in pulmonary function when postural changes in the sagittal plane are made in a seated position in patients diagnosed with chronic obstructive pulmonary disease (COPD).

Methods: Fourteen patients diagnosed with COPD participated in this study. Standard spirometric measurements (minute ventilation, forced vital capacity, and forced expiratory volume in 1 second) were taken for each patient in each of 2 sitting postures: slumped and upright. Breathing frequency, heart rate, and blood oxygen saturation were also recorded for each of the 2 postures. Patients assumed each posture for 5 minutes before any measurements were taken, after which measurements were recorded each minute for an additional 5 minutes.

Results: A 2-factor (posture and time) analysis of variance with repeated measures on both factors was used to analyze the data. There were no significant differences between the means for heart rate, blood oxygen saturation, and breathing frequency. Paired t tests likewise did not reveal any significant differences between the slumped and upright positions for forced expiratory volume in 1 second, forced vital capacity, and minute ventilation.

Conclusions: These results suggest that there are no differences in measures of pulmonary function (minute ventilation, forced vital capacity, and forced expiratory volume in 1 second) and breathing frequency, heart rate, and blood oxygen saturation between slumped and upright sitting in patients with COPD. Based on this evidence alone, it may be inappropriate to instruct a patient with COPD to sit upright to improve respiratory function. However, further study is warranted before any definite recommendations can be made regarding sitting posture and respiratory performance in individuals with COPD.