The Science Journal of the American Association for Respiratory Care

2008 OPEN FORUM Abstracts

PATTERNS OF TIDAL VOLUME DELIVERY DURING MECHANICAL VENTILATION: A RETROSPECTIVE REVIEW OF 2004-2007

Carl Haas1, Kimberly Bauser1, Linda Folk1, Susan Henning1, Paul Loik1, Bob McClish1, Michael Bandy1, Sue Hieber1



Background: Ventilator settings can influence patient outcome. ARDSNet demonstrated that a VT of 6 mL/kg of predicted body weight (PBW) with a Pplat ?30 cmH2O improved survival in ALI/ARDS patients. Studies suggest using VTs >10-12 mL/kg PBW may increase the likelihood of developing ALI/ARDS. Study Objectives: To determine: 1) tidal volume in mL/kg PBW, 2) VT vs Pplat relationship, and 3) PEEP levels used over a 4-year period.

Methods: A retrospective review of a departmental database from 2004-2007. Data included patient gender and height, and ventilator settings and airway pressures. PBW was calculated from the ARDSNet formula and used to compute VT in mL/kg PBW. Data from the first full day of MV was analyzed.

Results: Mean VT decreased each year. Mean VT in 2004 for 3 of 6 adult ICU's was >10 mL/kg PBW vs <9 mL/kg for all six ICUs in 2007. Females were ventilated with larger VTs than males by 10-13%. Mean Pplat remained constant. PEEP levels increased slightly each year; 12% of patients used >8 cmH2O in 2004 vs >30% in 2007. The % of patient with VT <10 mL/kg & Pplat <30 increased each year, while those with a VT >12 mL/kg decreased.

Conclusion: VT declined each year. To help ensure clinician awareness of the specific VT delivered, therapists are required to chart VT in mL/kg PBW. Whether these changes impacted development of ALI is unknown.