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Pressure characteristics of the Ambu CPAP system and the Servo Ventilator 900C in CPAP mode
Author(s) -
Zetterström H.,
Jonsson L. O.
Publication year - 1987
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/j.1399-6576.1987.tb02530.x
Subject(s) - medicine , anesthesia , servo , continuous positive airway pressure , intensive care medicine , mechanical engineering , obstructive sleep apnea , engineering
Spontaneous breathing was simulated in the Ambu continuous positive airway pressure (CPAP) system and the Servo ventilator 900C by means of a lung model programmed to mimic the respiratory flow patterns of a healthy volunteer and a patient in severe respiratory distress. Changes in airway pressure, flow and volume were recorded during “breathing” with CPAP at 0.5, 1.0 and 1.5 kPa. In the Ambu system, the airway‐pressure decreased during inspiration and increased during expiration, while the mean airway pressure was close to the pre‐set CPAP value. The pressure changes were minimal when the fresh gas flow was increased from 15 to 25 l·min ‐1 . The higher fresh gas (low is recommendable during deep or rapid breathing. In the Servo Ventilator 900C, there was a short initial inspiratory pressure drop, succeeded by a pressure rise above the CPAP value. The expiratory airway pressure was somewhat higher than CPAP. Both systems were found to be recommendable for clinical use.