Effect of Body Positions on Peak Expiratory Flow Rate Following Abdominal Surgery

Postoperative pulmonary complications following abdominal surgery are frequent and are associated with increased morbidity and mortality and hospital length of stay¹. The manipulation of abdominal cavity during upper abdominal surgery (UAS) decreases lung volume and capacity. This leads to shallow and rapid breathing, absence of deep breaths and paradoxical abdominal movements, which may cause pulmonary complications with altered ventilation-perfusion or pulmonary shunts that result in hypoxemia and atelectasis². The basic mechanism of PPCs is a lack of lung inflation that occurs because of a change in breathing to a shallow, monotonous breathing pattern with out periodic sighs, prolonged recumbent positioning and temporary diaphragmatic dysfunctions³.

Mucocilliary clearance also is impaired postoperatively, which along with the decreased cough effectiveness, increases risks associated with retained pulmonary secretions⁴. Atelectasis occurs regularly during general anesthesia induction, persists postoperatively and may contribute to significant morbidity and additional healthcare costs⁵. Two major causes of post operative Atelectasis are breathing with a rapid and shallow pattern of breathing and a reduced functional residual capacity, which in turn affects the gas exchange properties of the lung by increasing the ventilation/perfusion (v/q) mismatch, the situation may be further aggravated by hypoventilation due to sedation, pain and increased mechanical load⁶.

Body positioning has potent and direct effects on various steps in the oxygen transport pathway in health and in disease. Body position has been shown to affect lung volumes and muscle biomechanics⁷.

Subjects will be divided randomly into 3 groups with 20 in each group.

Group A-Long sitting position, Group B-Three-quarter sitting position, Group C-Chair sitting position. Patient in each specific group is made to sit comfortably in the above mentioned position. Routine chest physiotherapy including deep breathing exercises and incentive spirometry is given to all the 60 patients. Peak expiratory flow rate and thoracic excursion measurements of all the subjects were taken on 2nd and 7th post-operative day in their respective positions.

Results of the study showed significant improvement in PEFR and Thoracic excursion measurement in all three positions like Three quarter sitting, Long sitting, Chair sitting position. The results observed in the study has shown that the chair sitting position is most effective position for expiratory maneuvers for any physical therapy intervention following abdominal surgery compared to the other two positions like three quarter and long sitting. The more upright the patient is positioned the greater the neurological arousal and greater the stimulus to breathe, and increase alveolar ventilation and perfusion and hence augments V/Q matching⁸. This is noted with the significant improvement in PEFR and Thoracic excursion measurements.