The effect of body position on pulmonary function: a systematic review.

BACKGROUND: Pulmonary function tests (PFTs) are routinely performed in the upright position due to measurement devices and patient comfort. This systematic review investigated the influence of body position on lung function in healthy persons and specific patient groups. METHODS: A search to identify English-language papers published from 1/1998-12/2017 was conducted using MEDLINE and Google Scholar with key words: body position, lung function, lung mechanics, lung volume, position change, positioning, posture, pulmonary function testing, sitting, standing, supine, ventilation, and ventilatory change. Studies that were quasi-experimental, pre-post intervention; compared ≥2 positions, including sitting or standing; and assessed lung function in non-mechanically ventilated subjects aged ≥18 years were included. Primary outcome measures were forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC, FEV1/FVC), vital capacity (VC), functional residual capacity (FRC), maximal expiratory pressure (PEmax), maximal inspiratory pressure (PImax), peak expiratory flow (PEF), total lung capacity (TLC), residual volume (RV), and diffusing capacity of the lungs for carbon monoxide (DLCO). Standing, sitting, supine, and right- and left-side lying positions were studied. RESULTS: Forty-three studies met inclusion criteria. The study populations included healthy subjects (29 studies), lung disease (nine), heart disease (four), spinal cord injury (SCI, seven), neuromuscular diseases (three), and obesity (four). In most studies involving healthy subjects or patients with lung, heart, neuromuscular disease, or obesity, FEV1, FVC, FRC, PEmax, PImax, and/or PEF values were higher in more erect positions. For subjects with tetraplegic SCI, FVC and FEV1 were higher in supine vs. sitting. In healthy subjects, DLCO was higher in the supine vs. sitting, and in sitting vs. side-lying positions. In patients with chronic heart failure, the effect of position on DLCO varied. CONCLUSIONS: Body position influences the results of PFTs, but the optimal position and magnitude of the benefit varies between study populations. PFTs are routinely performed in the sitting position. We recommend the supine position should be considered in addition to sitting for PFTs in patients with SCI and neuromuscular disease. When treating patients with heart, lung, SCI, neuromuscular disease, or obesity, one should take into consideration that pulmonary physiology and function are influenced by body position.

Diagnosis and conservative management of late tracheotomy complications in chronic ventilator-dependent patients.

BACKGROUND: Complications associated with long-term tracheotomy are obstruction of the distal end of the tube by granulation tissue and tracheomalacia. These complications have traditionally been surgically treated. METHODS: Prospective study in a chronic ventilator-dependent division, including 234 consecutive patients with tracheotomy and mechanical ventilation. Endoscopic evaluation was performed in patients in whom there was respiratory distress with difficulty in passing a suction catheter through the tube, and/or increased inspiratory resistance and increased peak inspiratory pressure. RESULTS: Nineteen patients were diagnosed with granulation or tracheomalacia. Two patients were treated by surgical removal of the obstructing tissue. Nonsurgical patients were conservatively managed with symptoms' resolution by bypassing the pathology with a longer tube than the previous one or by an adjustable flange tube under endoscopic visualization, with a median symptom-free period of 433 days (range, 55-1230 days). CONCLUSION: In nonsurgical candidates, insertion of a longer tube is a conservative and feasible long-term treatment.