title: The comfort of breathing: a study with volunteers assessing the influence of various modes of assisted ventilation.
abstract: OBJECTIVE
  To assess the subjective feeling of comfort of healthy volunteers breathing on various modes of ventilation used in intensive care.
  
  
  METHODS
  A randomized, prospective, double-blinded, crossover trial using volunteers.
  
  
  METHODS
  An intensive care unit (ICU) in a teaching hospital.
  
  
  METHODS
  We compared, by using healthy volunteers, the subjective feeling of comfort of three modes of ventilation used during the weaning phase of critical illness. We used healthy volunteers to avoid other distracting influences of intensive care that may confound the primary feeling of comfort. The modes we compared were synchronized intermittent mandatory ventilation, assisted spontaneous breathing, and biphasic positive airway pressure. The imposed ventilation was comparable with 50% of the volunteers' normal respiratory effort. The volunteers breathed via a mouthpiece through a ventilator circuit, and the modes of ventilation were introduced in a randomized manner.
  
  
  RESULTS
  We measured visual analog scores for comfort for the three modes of ventilation and collected a ranking order and open-ended comments. We demonstrated that at the level of support we imposed, assisted spontaneous breathing was the most comfortable mode of ventilation and that synchronized intermittent mandatory ventilation was the most uncomfortable. These results were strongly supported by both the ranking scale and comments of the volunteers.
  
  
  CONCLUSIONS
  Assisted spontaneous breathing was the most comfortable mode of ventilation because the pattern was primarily determined by the volunteer. Synchronized intermittent mandatory ventilation was the most uncomfortable because the ventilatory pattern was imposed on the volunteers, leading to ventilator-volunteer dyssynchrony. We also conclude there is wide individual variation in the subjective feeling of comfort. Whereas the mode of ventilation in ICUs is based primarily on the physiologic needs of the patient, the feeling of comfort may be considered when choosing an appropriate mode of ventilation during the weaning phase of critical illness.
authors: Intensive Care Unit, Leicester Royal Infirmary, UK.
authors: W C
authors: WC
authors: Russell
authors: J R
authors: JR
authors: Greer
mesh_terms: D000328:Adult; D003422:Critical Care / Q000523:psychology*; D006801:Humans; D010147:Pain Measurement; D010342:Patient Acceptance of Health Care; D011175:Positive-Pressure Respiration / Q000523:psychology; D012121:Respiration, Artificial / Q000523:psychology*; D015300:Ventilator Weaning / Q000523:psychology; D014939:Work of Breathing