Effect of body positions on spirometric indices in healthy subjects

Different body positions have been shown to produce different lung function indices in diseased patients. However, this has not been well studied in the healthy Indian population. We aimed to study the effects of different body positions on spirometric lung function indices in healthy subjects. Methods : 60 non-smoking, asymptomatic, healthy male and female subjects between the ages of 18 to 25 underwent spirometry testing using the ndd ultrasonic spirometer, following ATS/ERS 2005 norms for quality. The following 5 positions were tested in a randomly generated sequence: sitting, supine, crook lying, right side lying and left side lying. The best of 3 repeatable values were considered for analysis. Differences in spirometric indices were analysed by comparing the mean± SD values using the paired t test. Results : FVC values were highest in the sitting position and lowest in the crook lying and left side lying positions. FEV1 was highest in the left side lying position and the lowest was crook lying. PEFR vales were highest in the sitting position and lowest in the supine position. Please see table 1. Table1: Spirometric indices in different body positions Positions(Mean ± SD) Left side lying Crook lying Right side lying Sitting Supine FEV1 L 2.66 ± 0.53 2.61 ± 0.63 2.64 ± 0.46 2.62 ±0.48 2.62 ± 0.44 FVC L 3.23 ± 0.79 3.17 ± 0.80 3.17 ± 1.04 3.35 ±0.62 3.22 ± 0.66 PEFR L/s 6.46 ± 1.70 6.42 ± 1.69 6.34 ± 1.29 6.83 ±1.22 6.20 ± 1.43 Conclusion : Overall the sitting position was found to be the most beneficial followed by left side lying followed by crook lying, supine lying and the least beneficial position was found to be the right side lying.