Helium-oxygen reduces work of breathing in mechanically ventilated patients with chronic obstructive pulmonary disease.
OBJECTIVE
To evaluate whether helium-oxygen mixture reduces inspiratory work of breathing (WOB) in sedated, paralyzed, and mechanically ventilated patients with acute exacerbation of chronic obstructive pulmonary disease (COPD).


METHODS
Open, prospective, randomized, crossover study in the medical intensive care unit in a university hospital.


METHODS
23 patients admitted for acute exacerbation of COPD and mechanically ventilated.


METHODS
Total WOB (WOBt), elastic WOB (WOBel), resistive WOB (WOBres), and WOB due to PEEPi (WOBPeepi) were measured. Static intrinsic positive end expiratory pressure (PEEPi), static compliance (Crs), inspiratory resistance (Rins), inspiratory (tinsp) and expiratory time constant (texp) were also measured. These variables were compared between air-oxygen and helium-oxygen mixtures.


RESULTS
WOBt significantly decreased with helium-oxygen (2.34+/-1.04 to 1.85+/-1.01 J/l, p<0.001). This reduction was significant for WOBel (1.02+/-0.61 J/l to 0.87+/-0.47, p<0.01), WOBPeepi (0.77+/-0.38 J/l to 0.54+/-0.38, p<0.001), and WOBres (0.55+/-0.19 J/l to 0.44+/-0.24, p<0.05). PEEPi, Rins, tinsp and texp significantly decreased. Crs was unchanged.


CONCLUSIONS
Helium-oxygen mixture decreases WOB in mechanically ventilated COPD patients. Helium-oxygen mixture could be useful to reduce the burden of ventilation.
Gainnier
Marc
M
Medical Intensive Care Unit, Hôpital Sainte-Marguerite, 13274 Marseille 9, France. Marc.Gainnier@mail.ap-hm.fr
Arnal
Jean-Michel
JM
Gerbeaux
Patrick
P
Donati
Stéphane
S
Papazian
Laurent
L
Sainty
Jean-Marie
JM
D000368:Aged; D018592:Cross-Over Studies; D005260:Female; D006371:Helium / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D010100:Oxygen / Q000627:therapeutic use*; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology* / Q000628:therapy*; D012121:Respiration, Artificial; D014939:Work of Breathing / Q000187:drug effects*
D006371:Helium; D010100:Oxygen