title: Noninvasive positive pressure ventilation using a helmet in patients with acute exacerbation of chronic obstructive pulmonary disease: a feasibility study.
abstract: BACKGROUND
  Noninvasive positive pressure ventilation (NPPV) with a facemask (FM) is effective in patients with acute exacerbation of their chronic obstructive pulmonary disease. Whether it is feasible to treat these patients with NPPV delivered by a helmet is not known.
  
  
  METHODS
  Over a 4-month period, the authors studied 33 chronic obstructive pulmonary disease patients with acute exacerbation who were admitted to four intensive care units and treated with helmet NPPV. The patients were compared with 33 historical controls treated with FM NPPV, matched for simplified acute physiologic score (SAPS II), age, PaCO2, pH, and PaO2:fractional inspired oxygen tension. The primary endpoints were the feasibility of the technique, improvement of gas exchange, and need for intubation.
  
  
  RESULTS
  The baseline characteristics of the two groups were similar. Ten patients in the helmet group and 14 in the FM group (P = 0.22) were intubated. In the helmet group, no patients were unable to tolerate NPPV, whereas five patients required intubation in the FM group (P = 0.047). After 1 h of treatment, both groups had a significant reduction of PaCO2 with improvement of pH; PaCO2 decreased less in the helmet group (P = 0.01). On discontinuing support, PaCO2 was higher (P = 0.002) and pH lower (P = 0.02) in the helmet group than in the control group. One patient in the helmet group, and 12 in the FM group, developed complications related to NPPV (P < 0.001). Length of intensive care unit stay, intensive care unit, and hospital mortality were similar in both groups.
  
  
  CONCLUSIONS
  Helmet NPPV is feasible and can be used to treat chronic obstructive pulmonary disease patients with acute exacerbation, but it does not improve carbon dioxide elimination as efficiently as does FM NPPV.
authors.affiliation: Istituto di Anestesiologia e Rianimazione, Università Cattolica del Sacro Cuore, Rome, Italy. m.antonelli@rm.unicatt.it
authors.forename: Massimo
authors.initials: M
authors.lastname: Antonelli
authors.forename: Mariano Alberto
authors.initials: MA
authors.lastname: Pennisi
authors.forename: Paolo
authors.initials: P
authors.lastname: Pelosi
authors.forename: Cesare
authors.initials: C
authors.lastname: Gregoretti
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Squadrone
authors.forename: Monica
authors.initials: M
authors.lastname: Rocco
authors.forename: Luca
authors.initials: L
authors.lastname: Cecchini
authors.forename: Davide
authors.initials: D
authors.lastname: Chiumello
authors.forename: Paolo
authors.initials: P
authors.lastname: Severgnini
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Proietti
authors.forename: Paolo
authors.initials: P
authors.lastname: Navalesi
authors.forename: Giorgio
authors.initials: G
authors.lastname: Conti
mesh_terms: D000142:Acidosis, Respiratory / Q000503:physiopathology; D000208:Acute Disease; D000368:Aged; D002245:Carbon Dioxide / Q000097:blood / Q000378:metabolism; D023381:Endpoint Determination; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal; D008297:Male; D008397:Masks; D008991:Monitoring, Physiologic; D011175:Positive-Pressure Respiration / Q000295:instrumentation*; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000628:therapy*; D012129:Respiratory Function Tests; D016896:Treatment Outcome; D015300:Ventilator Weaning
chemical_list: D002245:Carbon Dioxide