A long-term clinical evaluation of autoflow during assist-controlled ventilation: a randomized controlled trial.
BACKGROUND
Many new mechanical ventilation modes are proposed without any clinical evaluation. "Dual-controlled" modes, such as AutoFlow™, are supposed to improve patient- ventilator interfacing and could lead to fewer alarms. We performed a long-term clinical evaluation of the efficacy and safety of AutoFlow during assist-controlled ventilation, focusing on ventilator alarms.


METHODS
Forty-two adult patients, receiving mechanical ventilation for more than 2 days with a Dräger Evita 4 ventilator were randomized to conventional (n = 21) or AutoFlow (n = 21) assist-controlled ventilation. Sedation was given using a nurse-driven protocol. Ventilator-generated alarms were exhaustively recorded from the ventilator logbook with a computer. Daily blood gases and ventilation outcome were recorded.


RESULTS
A total of 403 days of mechanical ventilation were studied and 45,022 alarms were recorded over a period of 8074 hours. The course of respiratory rate, minute ventilation, Fio(2), positive end-expiratory pressure, Pao(2)/Fio(2), Paco(2), and pH and doses and duration of sedation did not differ between the 2 groups. Outcome (duration of mechanical ventilation, ventilator-associated pneumonia, course of Sequential Organ Failure Assessment score, or death) was not different between the 2 groups. The number of alarms per hour was lower with AutoFlow assist-controlled ventilation: 3.3 [1.5 to 17] versus 9.1 [5 to 19], P < 0.0001 (median [quartile range]). In multivariate analysis, a low alarm rate was associated with activation of AutoFlow and a higher midazolam dose.


CONCLUSIONS
This first long-term clinical evaluation of the AutoFlow mode demonstrated its safety with regard to gas exchange and patient outcome. AutoFlow also allowed a very marked reduction in the number of ventilator alarms.
Lasocki
Sigismond
S
Réanimation Chirurgicale, CHU Bichat, 46 rue Henri Huchard, 75018 Paris, France. sigismond@lasocki.com
Labat
Françoise
F
Plantefeve
Gaetan
G
Desmard
Mathieu
M
Mentec
Hervé
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D012121:Respiration, Artificial / Q000295:instrumentation / Q000379:methods* / Q000592:standards*; D056152:Respiratory Rate / Q000187:drug effects / Q000502:physiology; D013997:Time Factors
D006993:Hypnotics and Sedatives