Rationale:
Previous research has demonstrated that healthy individuals who maintain a slumped seated position have a decrease in pulmonary function when compared to an upright seated position.
Objectives:
The purpose of this study was to investigate the 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:
Nineteen patients (mean age = 70.4, mean BMI = 29.5) with a medical diagnosis of COPD were recruited to participate in this study. Standard spirometric measurements (minute ventilation (VE), forced vital capacity (FVC), and forced expiratory volume in one second (FEV1)) were taken for each patient in each of two sitting postures, slumped and upright. Breathing frequency (bf), heart rate (HR), and blood oxygen saturation (O2 sat)) were also recorded for each of the two postures. Patients assumed each posture for 5 minutes before any measurements were taken, after which time measurements were recorded each minute for an additional 5 minutes.
Results:
A two factor (posture and time) ANOVA with repeated measures on both factors was used to analyze the data. There were no significant differences between the means for HR, O2 sat, and bf (Ps >.05). Paired t-tests likewise did not reveal any significant differences between the slumped and upright positions for FEV1, FVC, and VE (Ps >.05).
Conclusion:
These results suggest that there are no differences in measures of pulmonary function (VE, FVC, and FEV1) and breathing frequency, heart rate, and O2 saturation between slumped and upright sitting in patients with COPD. Unlike healthy subjects who demonstrate improved pulmonary function with upright posture, patients with COPD may not demonstrate the same benefit because a slumped posture may actually place the characteristic flattened diaphragm in a more advantageous biomechanical position than would an upright posture.