title: New versus Conventional Helmet for Delivering Noninvasive Ventilation: A Physiologic, Crossover Randomized Study in Critically Ill Patients.
abstract: BACKGROUND
  The helmet is a well-tolerated interface for noninvasive ventilation, although it is associated with poor patient-ventilator interaction. A new helmet (NH) has proven to attenuate this limitation of the standard helmet (SH) in both bench study and healthy volunteers. The authors compared a NH and a SH in intensive care unit patients receiving noninvasive ventilation for prevention of postextubation respiratory failure; both helmets were also compared with the endotracheal tube in place before extubation.
  
  
  METHODS
  Fourteen patients underwent 30-min trials in pressure support during invasive ventilation and then with a SH and a NH in a random order. The authors measured comfort, triggering delays, rates of pressurization (airway pressure-time product [PTP] of the first 300 [PTP(300-index)] and 500 [PTP(500-index)] ms from the onset of effort, and the first 200 ms from the onset of insufflation [PTP200]), time of synchrony between effort and assistance (Time(synch)/Ti(neu)), respiratory drive and frequency, arterial blood gases (ABGs), and rate of asynchrony.
  
  
  RESULTS
  Compared with SH, NH improved comfort (5.5 [5.0 to 6.0] vs. 8.0 [7.8 to 8.0]), respectively, P < 0.001), inspiratory trigger delay (0.31 [0.22 to 0.43] vs. 0.25 [0.18 to 0.31] s, P = 0.007), and pressurization (PTP(300-index): 0.8 [0.1 to 1.8] vs. 2.7 [7.1 to 10.0]%; PTP(500-index): 4.8 [2.5 to 9.9] vs. 27.3 [16.2 to 34.8]%; PTP200: 13.6 [10.1 to 19.6] vs. 30.4 [24.9 to 38.4] cm H2O/s, P < 0.01 for all comparisons) and Time(synch)/Ti(neu) (0.64 [0.48 to 0.72] vs. 0.71 [0.61 to 0.81], P = 0.007). Respiratory drive and frequency, ABGs, and rate of asynchrony were not different between helmets. Endotracheal tube outperformed both helmets with respect to all variables, except for respiratory rate, ABGs, and asynchronies.
  
  
  CONCLUSIONS
  Compared with a SH, a NH improved comfort and patient-ventilator interaction.
authors.affiliation: From Anesthesia and Intensive Care, "Maggiore Della Carità" Hospital, Novara, Italy (C.O., G.C., R.V., A.M., P.B., F.D.C.); Anesthesia and Intensive Care, Sant'Andrea Hospital, ASL VC, Vercelli, Italy (F.L., P.N.); the Medical Statistics and Cancer Epidemiology Unit, Eastern Piedmont University "A. Avogadro," Novara, Italy (T.C., C.M.); the Department of Translational Medicine, Eastern Piedmont University "A. Avogadro," Novara, Italy (F.D.C., P.N.); and CRRF Mons. L. Novarese, Moncrivello (VC), Italy (P.N.).
authors.forename: Carlo
authors.initials: C
authors.lastname: Olivieri
authors.forename: Federico
authors.initials: F
authors.lastname: Longhini
authors.forename: Tiziana
authors.initials: T
authors.lastname: Cena
authors.forename: Gianmaria
authors.initials: G
authors.lastname: Cammarota
authors.forename: Rosanna
authors.initials: R
authors.lastname: Vaschetto
authors.forename: Antonio
authors.initials: A
authors.lastname: Messina
authors.forename: Paola
authors.initials: P
authors.lastname: Berni
authors.forename: Corrado
authors.initials: C
authors.lastname: Magnani
authors.forename: Francesco
authors.initials: F
authors.lastname: Della Corte
authors.forename: Paolo
authors.initials: P
authors.lastname: Navalesi
mesh_terms: D000328:Adult; D000368:Aged; D003422:Critical Care / Q000379:methods*; D016638:Critical Illness; D018592:Cross-Over Studies; D004867:Equipment Design; D005260:Female; D006260:Head Protective Devices; D006801:Humans; D008297:Male; D008875:Middle Aged; D063087:Noninvasive Ventilation / Q000295:instrumentation*; D011446:Prospective Studies