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Additive effects of non‐invasive ventilation to hyperoxia on cerebral oxygenation in COPD patients with exercise‐related O 2 desaturation
Author(s) -
Rodrigues Miguel K.,
Oliveira Mayron F.,
Soares Aline,
Treptow Erika,
Neder J Alberto
Publication year - 2013
Publication title -
clinical physiology and functional imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.608
H-Index - 67
eISSN - 1475-097X
pISSN - 1475-0961
DOI - 10.1111/cpf.12024
Subject(s) - medicine , copd , impedance cardiography , oxygenation , hyperoxia , anesthesia , ventilation (architecture) , stroke volume , respiratory minute volume , cardiac output , cardiology , heart rate , hemodynamics , respiratory system , blood pressure , lung , mechanical engineering , engineering
Summary Background It is currently unknown whether potential haemodynamic improvements induced by non‐invasive ventilation ( NIV ) would positively impact upon cerebral oxygenation ( CO x) in patients with moderate‐to‐severe chronic obstructive pulmonary disease ( COPD ). Objective To investigate the effects of NIV on exercise CO x in COPD patients presenting with exercise‐related O 2 desaturation. Methods On a double‐blind trial, 13 males ( FEV 1 = 48·8 ± 15·1% predicted) were randomly assigned to NIV (16 cmH 2 O IPS and 5 cmH 2 O PEEP ) plus HO x ( FiO 2 = 0·4) or sham NIV (7 cmH 2 O IPS and 5 cmH 2 O PEEP to overcome breathing circuit resistance) plus HO x during ramp‐incremental exercise performed on different days. Near‐infrared spectroscopy and impedance cardiography assessed changes (Δ) in CO x and cardiac output ( Q T ), respectively. Results There were no significant between‐intervention differences in peak work rate, ventilation and reported symptoms ( P >0·05). Peripheral oxyhaemoglobin saturation remained above 98% throughout the tests. NIV + HO x was associated with larger increases in Δ CO x, Δ Q T and Δ stroke volume at maximal and submaximal exercise ( P <0·05). Increases in the area under the curve (to an iso‐work rate) of Δ CO x under NIV + HO x were significantly ( P <0·01) correlated with improvements in Δ Q T (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 + HO x ( P >0·05). Conclusions NIV added benefit to HO x in improving central haemodynamics and CO x in O 2 ‘desaturators’ with COPD . The clinical relevance of such beneficial effects on exercise tolerance, however, remains to be demonstrated.