The automatic selection of ventilation parameters during the initial phase of mechanical ventilation.
OBJECTIVE
To test a method that allows automatic set-up of the ventilator controls at the onset of ventilation.


METHODS
Prospective randomized crossover study.


METHODS
ICUs in one adult and one children's hospital in Switzerland.


METHODS
Thirty intubated stable, critically ill patients (20 adults and 10 children).


METHODS
The patients were ventilated during two 20-min periods using a modified Hamilton AMADEUS ventilator. During the control period the ventilator settings were chosen immediately prior to the study. During the other period individual settings were automatically determined by the ventilatior (AutoInit).


RESULTS
Pressure, flow, and instantaneous CO2 concentration were measured at the airway opening. From these measurements, series dead space (V(DS)), expiratory time constant (RC), tidal volume (VT, total respiratory frequency (f(tot), minute ventilation (MV), and maximal and mean airway pressure (Paw, max and Paw, mean) were calculated. Arterial blood gases were analyzed at the end of each period. Paw, max was significantly less with the AutoInit ventilator settings while f(tot) was significantly greater (P < 0.05). The other values were not statistically significant.


CONCLUSIONS
The AutoInit ventilator settings, which were automatically derived, were acceptable for all patients for a period of 20 min and were not found to be inferior to the control ventilator settings. This makes the AutoInit method potentially useful as an automatic start-up procedure for mechanical ventilation.
Laubscher
T P
TP
Hamilton Bonaduz AG, Switzerland.
Frutiger
A
A
Fanconi
S
S
Brunner
J X
JX
D000328:Adult; D000368:Aged; D001784:Blood Gas Analysis; D002648:Child; D002675:Child, Preschool; D018592:Cross-Over Studies; D006801:Humans; D008176:Lung Volume Measurements; D008875:Middle Aged; D008991:Monitoring, Physiologic; D011175:Positive-Pressure Respiration / Q000379:methods*; D011446:Prospective Studies; D012131:Respiratory Insufficiency / Q000097:blood / Q000503:physiopathology / Q000628:therapy*; D013813:Therapy, Computer-Assisted / Q000379:methods*