Pressure support ventilation increases cardiac output in neonates and infants.
Fifteen neonates and infants were investigated during pressure controlled ventilation (PCV) and pressure support ventilation (PSV) on a Servo 300 ventilator. Changes in cardiac output (aortic mean blood flow velocity) were assessed with the Doppler technique. During PSV cardiac output increased by 16% (P < 0.01) compared with PCV with equal ventilation. Mean airway pressure decreased significantly during PSV compared with PCV, which may explain the increased cardiac output. During PSV, when inspiratory/expiratory (I:E) relations are dependent on the patient, we found a lower I:E ratio compared with PCV. It can be assumed that at least part of the decreased mean airway pressure is caused by the lower I:E ratio. As the heart rate was unchanged, the variations in cardiac output were caused by alterations in stroke volume. It is concluded that a patient triggered mode should be preferred providing that the neonate/infant has the ability to elicit the ventilator's triggering system.
Gullberg
N
N
Department of Paediatric Anaesthesia and Intensive Care, Görans Hospital, Karolinska Institute, Stockholm, Sweden.
Winberg
P
P
Selldén
H
H
D000403:Airway Resistance; D001011:Aorta / Q000502:physiology; D001783:Blood Flow Velocity; D002302:Cardiac Output; D006339:Heart Rate; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D011175:Positive-Pressure Respiration; D012119:Respiration; D018608:Ultrasonography, Doppler