title: Exposure to noise during continuous positive airway pressure: influence of interfaces and delivery systems.
abstract: BACKGROUND
  We measured noise intensity and perceived noisiness during continuous positive airway pressure (CPAP) performed with two interfaces (face-mask, helmet) and four delivery systems.
  
  
  METHODS
  Eight healthy volunteers received CPAP in random order with: two systems provided with a flow generator using the Venturi effect and a mechanical expiratory valve (A: Venturi, Starmed; B: Whisperflow-2, Caradyne Ltd); one 'free-flow' system provided with high flow O(2) and air flowmeters, an inspiratory gas reservoir, and a water valve (C: CF800, Drägerwerk, AG); and a standard mechanical ventilator (Servoventilator 300, Siemens-Elema). Systems A, B, and C were tested with a face-mask and a helmet at a CPAP value of 10 cm H(2)O; the mechanical ventilator was only tested with the face mask. Noise intensity was measured with a sound-level meter. After each test, participants scored noisiness on a visual analog scale (VAS).
  
  
  RESULTS
  The noise levels measured ranged from 57+/-11 dBA (mechanical ventilator plus mask) to 93+/-1 and 94+/-2 dBA (systems A and B plus helmet) and were significantly affected by CPAP systems (A and B noisier than C and D) and interfaces (helmet CPAP noisier than mask CPAP). Subjective evaluation showed that systems A and B plus helmet were perceived as noisier than system C plus mask or helmet.
  
  
  CONCLUSIONS
  Maximum noise levels observed in this study may potentially cause patient discomfort. Less noisy CPAP systems (not using Venturi effect) and interfaces (facial mask better than helmet) should be preferred, particularly for long or nocturnal treatments.
authors.affiliation: Institute of Anaesthesia and Intensive Care, Catholic University of the Sacred Heart, Largo Francesco Vito, 1, Rome, Italy. f.cavaliere@rm.unicatt.it
authors.forename: F
authors.initials: F
authors.lastname: Cavaliere
authors.forename: G
authors.initials: G
authors.lastname: Conti
authors.forename: R
authors.initials: R
authors.lastname: Costa
authors.forename: G
authors.initials: G
authors.lastname: Spinazzola
authors.forename: R
authors.initials: R
authors.lastname: Proietti
authors.forename: A
authors.initials: A
authors.lastname: Sciuto
authors.forename: S
authors.initials: S
authors.lastname: Masieri
mesh_terms: D000328:Adult; D001307:Auditory Perception; D045422:Continuous Positive Airway Pressure / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods / Q000523:psychology; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008397:Masks; D008875:Middle Aged; D009622:Noise / Q000009:adverse effects; D010342:Patient Acceptance of Health Care / Q000523:psychology*