Effects of Upper Trunk Flexion on Ventilation Volume in Semi-Fowler’s Position: Cross-Sectional Study

Introduction

Semi-Fowler’s position with the trunk raised 30° from supine improves respiratory function and reduces cardiovascular stress. Upper trunk flexion’s effects on ventilation remain uninvestigated despite known cardiovascular benefits.

Objective

To compare ventilation volumes between semi-Fowler’s position with upper trunk flexion (UT30) and whole trunk elevation (WT30) in a cross-sectional study.

Methods

Fourteen healthy young women participated. Ventilation parameters were measured in supine (SPIN), UT30, and WT30 positions. Tidal volume, minute ventilation, respiratory rate, RR intervals, and subjective breathing difficulty were assessed and analyzed using linear mixed models. Results: Both UT30 and WT30 showed significantly higher tidal volume than SPIN (p<0.05).

Minute ventilation was significantly higher in UT30 compared to SPIN. RRi was significantly lower in WT30 compared to SPIN, with no difference between UT30 and SPIN.

Conclusion

Upper trunk flexion improves ventilation volume similar to whole trunk elevation while maintaining cardiovascular stability, potentially benefiting patients requiring respiratory support with minimal hemodynamic compromise.

KEY POINTS

This study investigates the effect of upper trunk flexion in a semi-Fowler’s position on ventilation volume, comparing it with a conventional semi-Fowler’s position that raises the entire trunk.

Upper trunk flexion in a semi-Fowler’s position resulted in a significant increase in tidal volume, comparable to that achieved by raising the entire trunk. This suggests that upper trunk flexion can effectively enhance ventilation volume without fully elevating the trunk.

Upper trunk flexion offers a simple yet effective intervention to improve ventilation in clinical settings, particularly beneficial for patients who cannot tolerate full Fowler’s positioning.