Non-invasive ventilation in chronic obstructive pulmonary disease patients: helmet versus facial mask.
BACKGROUND
The helmet is a new interface with the potential of increasing the success rate of non-invasive ventilation by improving tolerance.


OBJECTIVE
To perform a physiological comparison between the helmet and the conventional facial mask in delivering non-invasive ventilation in hypercapnic patients with chronic obstructive pulmonary disease.


METHODS
Prospective, controlled, randomized study with cross-over design. In 10 patients we evaluated gas exchange, inspiratory effort, patient-ventilator synchrony and patient tolerance after 30 min of non-invasive ventilation delivered either by helmet or facial mask; both trials were preceded by periods of spontaneous unassisted breathing.


METHODS
Arterial blood gases, inspiratory effort, duration of diaphragm contraction and ventilator assistance, effort-to-support delays (at the beginning and at the end of inspiration), number of ineffective efforts, and patient comfort.


RESULTS
Non-invasive ventilation improved gas exchange (p<0.05) and inspiratory effort (p<0.01) with both interfaces. The helmet, however, was less efficient than the mask in reducing inspiratory effort (p<0.05) and worsened the patient-ventilator synchrony, as indicated by the longer delays to trigger on (p<0.05) and cycle off (p<0.05) the mechanical assistance and by the number of ineffective efforts (p<0.005). Patient comfort was no different with the two interfaces.


CONCLUSIONS
Helmet and facial mask were equally tolerated and both were effective in ameliorating gas exchange and decreasing inspiratory effort. The helmet, however, was less efficient in decreasing inspiratory effort and worsened the patient-ventilator interaction.
Navalesi
Paolo
P
Pneumologia Riabilitativa e Terapia Intensiva Respiratoria, Fondazione S. Maugeri IRCCS, Via S. Maugeri 10, 27100, Pavia, Italy. paolo.navalesi@fastwebnet.it
Costa
Roberta
R
Ceriana
Piero
P
Carlucci
Annalisa
A
Prinianakis
George
G
Antonelli
Massimo
M
Conti
Giorgio
G
Nava
Stefano
S
D000368:Aged; D000369:Aged, 80 and over; D018592:Cross-Over Studies; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008397:Masks; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000628:therapy*; D012121:Respiration, Artificial / Q000295:instrumentation*