title: Patient comfort during pressure support and volume controlled-continuous mandatory ventilation.
abstract: BACKGROUND
  Pressure-support ventilation (PSV) is more comfortable than volume controlled-continuous mandatory ventilation (VC-CMV) in acute hypercapnic respiratory failure, in patients undergoing noninvasive ventilation. Physiologic measurements of patient status have been compared in PSV and VC-CMV in endotracheally intubated patients, but patient perception of comfort has not been measured in this population.
  
  
  OBJECTIVE
  To determine if PSV is more comfortable than VC-CMV (volume-cycled, flow-limited) in intubated mechanically ventilated patients.
  
  
  METHODS
  In a randomized prospective trial, patients underwent PSV and VC-CMV for 30 min each, separated by a 30 min washout with the baseline ventilation mode (pressure-regulated volume-control ventilation [PRVC]). The level of pressure support was set as the plateau pressure on VC-CMV with a tidal volume of 8 mL/kg minus the end-expiratory pressure. After each mode the patient was asked to mark his or her comfort level on a visual analog scale.
  
  
  RESULTS
  Eleven of the 14 patients were more comfortable during PSV. The baseline mean comfort score (during PRVC) was 62 +/- 18 (95% confidence interval 51.7-72.5). The mean comfort score for PSV was 83 +/- 11 (95% confidence interval 76.9-89.6). The mean comfort score for VC-CMV was 70 +/- 18 (95% confidence interval 59.4-79.9). PSV was significantly more comfortable than VC-CMV (p = 0.02) or PRVC (p = 0.009), whereas the comfort scores for VC-CMV and PRVC were not significantly different (p = 0.278). Respiratory rate, blood pressure, heart rate, minute ventilation, and blood oxygen saturation showed no difference between PRVC, VC-CMV, and PSV.
  
  
  CONCLUSIONS
  On average the patients felt more comfortable during PSV than during VC-CMV or PRVC, so PSV may be the preferred mode for awake intubated patients.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Henry Ford Hospital, 2799 W Grand Boulevard, K-17, Detroit MI 48202, USA. abetens1@hfhs.org
authors.forename: Alan D
authors.initials: AD
authors.lastname: Betensley
authors.forename: Imran
authors.initials: I
authors.lastname: Khalid
authors.forename: John
authors.initials: J
authors.lastname: Crawford
authors.forename: Robert A
authors.initials: RA
authors.lastname: Pensler
authors.forename: Bruno
authors.initials: B
authors.lastname: DiGiovine
mesh_terms: D000328:Adult; D000368:Aged; D016001:Confidence Intervals; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D012121:Respiration, Artificial / Q000379:methods* / Q000592:standards; D012131:Respiratory Insufficiency / Q000503:physiopathology / Q000628:therapy*; D012189:Retrospective Studies; D013990:Tidal Volume / Q000502:physiology*; D016896:Treatment Outcome