Effects of Implementing Adaptive Support Ventilation in a Medical Intensive Care Unit

• Published in: Respiratory care 2011-07, Vol.56 (7), p.976-983
• Main Authors: CHEN, Chien-Wen, WU, Chin-Pyng, DAI, Yu-Ling, PERNG, Wann-Cherng, CHIAN, Chih-Feng, SU, Wen-Lin, HUANG, Yuh-Chin T
• Format: Article
• Language: English
• Subjects: Acute respiratory distress syndrome; Aged; Analysis; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Artificial respiration; Biological and medical sciences; Care and treatment; Case-Control Studies; Clinical death. Palliative care. Organ gift and preservation; Female; Health aspects; Humans; Intensive care medicine; Intensive Care Units; Logistic Models; Male; Management; Medical sciences; Pilot Projects; Prospective Studies; Respiration, Artificial - methods; Respiratory Insufficiency - therapy; Respiratory Mechanics; Ventilator Weaning
• ISSN: 0020-1324; 1943-3654
• DOI: 10.4187/respcare.00966

Adaptive support ventilation (ASV) facilitates ventilator liberation in postoperative patients in surgical intensive care units (ICU). Whether ASV has similar benefits in patients with acute respiratory failure is unclear. We conducted a pilot study in a medical ICU that manages approximately 600 mechanically ventilated patients a year. The ICU has one respiratory therapist who manages ventilators twice during the day shift (8:00 am to 5:00 pm). No on-site respiratory therapist was present at night. We prospectively enrolled 79 patients mechanically ventilated for ≥ 24 hours on pressure support of ≥ 15 cm H(2)O, with or without synchronized intermittent mandatory ventilation, F(IO(2)) ≤ 50%, and PEEP ≤ 8 cm H(2)O. We switched the ventilation mode to ASV starting at a "%MinVol" setting of 80-100%. We defined spontaneous breathing trial (SBT) readiness as a frequency/tidal-volume ratio of < 105 (breaths/min)/L on pressure support of ≤ 8 cm H(2)O and PEEP of ≤ 5 cm H(2)O for at least 2 h, and all spontaneous breaths. The T-piece SBT was considered successful if the frequency/tidal-volume ratio remained below 105 (breaths/min)/L for 30 min, and we extubated after successful SBT. The control group consisted of 70 patients managed with conventional ventilation modes and a ventilator protocol during a 6-month period immediately before the ASV study period. Extubation was attempted in 73% of the patients in the ASV group, and 80% of the patients in the non-ASV group. The re-intubation rates in the ASV and non-ASV groups were 5% and 7%, respectively. In the ASV group, 20% of the patients achieved extubation readiness within 1 day, compared to 4% in the non-ASV group (P =