Additive effects of non‐invasive ventilation to hyperoxia on cerebral oxygenation in COPD patients with exercise‐related O2 desaturation. (21st January 2013)

• Record Type: Journal Article
• Authors: Rodrigues, Miguel K.; Oliveira, Mayron F.; Soares, Aline; Treptow, Erika; Neder, J Alberto
• Is Part Of: Clinical physiology and functional imaging. Volume 33:Number 4(2013:Jul.)
• Page Start: 274
• Page End: 281
• Publication Date: 2013-01-21
• Subjects: Physiology, Pathological -- Periodicals; Diagnostic imaging -- Periodicals; 612
• DOI: 10.1111/cpf.12024
• Languages: English
• ISSNs: 1475-0961

Abstract

<abstract abstract-type="main" xml:lang="en" id="cpf12024-abs-0001"> <title>Summary</title> <sec id="cpf12024-sec-0001" sec-type="section"> <title>Background</title> <p>It is currently unknown whether potential haemodynamic improvements induced by non‐invasive ventilation (NIV) would positively impact upon cerebral oxygenation (COx) in patients with moderate‐to‐severe chronic obstructive pulmonary disease (COPD).</p> </sec> <sec id="cpf12024-sec-0002" sec-type="section"> <title>Objective</title> <p>To investigate the effects of NIV on exercise COx in COPD patients presenting with exercise‐related O<sub>2</sub> desaturation.</p> </sec> <sec id="cpf12024-sec-0003" sec-type="section"> <title>Methods</title> <p>On a double‐blind trial, 13 males (FEV<sub>1 </sub>= 48·8 ± 15·1% predicted) were randomly assigned to NIV (16 cmH<sub>2</sub>O IPS and 5 cmH<sub>2</sub>O PEEP) <italic>plus </italic>HOx (FiO<sub>2 </sub>= 0·4) or sham NIV (7 cmH<sub>2</sub>O IPS and 5 cmH<sub>2</sub>O PEEP to overcome breathing circuit resistance) <italic>plus </italic>HOx during ramp‐incremental exercise performed on different days. Near‐infrared spectroscopy and impedance cardiography assessed changes (Δ) in COx and cardiac output (Q<sub>T</sub>), respectively.</p> </sec> <sec id="cpf12024-sec-0004" sec-type="section"> <title>Results</title> <p>There were no significant between‐intervention differences in peak work rate, ventilation and reported symptoms (<italic>P</italic>>0·05). Peripheral oxyhaemoglobin saturation remained above 98% throughout the tests. NIV + HOx was associated with larger increases in Δ COx, Δ Q<sub>T</sub> and Δ stroke volume at maximal and submaximal exercise (<italic>P</italic><0·05). Increases in the area under the curve (to an iso‐work rate) of Δ COx under NIV + HOx were significantly (<italic>P</italic><0·01) correlated with improvements in Δ Q<sub>T</sub> (r = 0·82) and Δ stroke volume (r = 0·87). There was, however, no significant correlation between enhancement in these physiological responses with changes in peak work rate with NIV + HOx (<italic>P</italic>>0·05).</p> </sec> <sec id="cpf12024-sec-0005" sec-type="section"> <title>Conclusions</title> <p>NIV added benefit to HOx in improving central haemodynamics and COx in O<sub>2</sub> 'desaturators' with COPD. The clinical relevance of such beneficial effects on exercise tolerance, however, remains to be demonstrated.</p> </sec> </abstract>