title: Positive outcome of average volume-assured pressure support mode of a Respironics V60 Ventilator in acute exacerbation of chronic obstructive pulmonary disease: a case report.
abstract: BACKGROUND
  We were able to treat a patient with acute exacerbation of chronic obstructive pulmonary disease who also suffered from sleep-disordered breathing by using the average volume-assured pressure support mode of a Respironics V60 Ventilator (Philips Respironics: United States). This allows a target tidal volume to be set based on automatic changes in inspiratory positive airway pressure. This removed the need to change the noninvasive positive pressure ventilation settings during the day and during sleep. The Respironics V60 Ventilator, in the average volume-assured pressure support mode, was attached to our patient and improved and stabilized his sleep-related hypoventilation by automatically adjusting force to within an acceptable range.
  
  
  METHODS
  Our patient was a 74-year-old Japanese man who was hospitalized for treatment due to worsening of dyspnea and hypoxemia. He was diagnosed with acute exacerbation of chronic obstructive pulmonary disease and full-time biphasic positive airway pressure support ventilation was initiated. Our patient was temporarily provided with portable noninvasive positive pressure ventilation at night-time following an improvement in his condition, but his chronic obstructive pulmonary disease again worsened due to the recurrence of a respiratory infection. During the initial exacerbation, his tidal volume was significantly lower during sleep (378.9 ± 72.9mL) than while awake (446.5 ± 63.3mL). A ventilator that allows ventilation to be maintained by automatically adjusting the inspiratory force to within an acceptable range was attached in average volume-assured pressure support mode, improving his sleep-related hypoventilation, which is often associated with the use of the Respironics V60 Ventilator. Polysomnography performed while our patient was on noninvasive positive pressure ventilation revealed obstructive sleep apnea syndrome (apnea-hypopnea index = 14), suggesting that his chronic obstructive pulmonary disease was complicated by obstructive sleep apnea syndrome.
  
  
  CONCLUSIONS
  In cases such as this, in which patients with severe acute respiratory failure requiring full-time noninvasive positive pressure ventilation therapy also show sleep-disordered breathing, different ventilator settings must be used for waking and sleeping. On such occasions, the Respironics V60 Ventilator, which is equipped with an average volume-assured pressure support mode, may be useful in improving gas exchange and may achieve good patient compliance, because that mode allows ventilation to be maintained by automatically adjusting the inspiratory force to within an acceptable range whenever ventilation falls below target levels.
authors.affiliation: Osaka Hospital, Neyagawakoen 2276-1, Neyagawa City, Osaka, 572-0854, Japan. ryoheikunn@msf.biglobe.ne.jp.
authors.forename: Miyuki
authors.initials: M
authors.lastname: Okuda
authors.forename: Makoto
authors.initials: M
authors.lastname: Kashio
authors.forename: Nobuya
authors.initials: N
authors.lastname: Tanaka
authors.forename: Takashi
authors.initials: T
authors.lastname: Fujii
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Okuda