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High‐Frequency Positive‐Pressure Ventilation (HFPPV) Applied for Small Lung Ventilation and Compared with Spontaneous Respiration and Continuous Positive Airway Pressure (CPAP)
Author(s) -
Jonzon A.,
Sedin G.,
Sjöstrand U.
Publication year - 1974
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.1399-6576.1974.tb00779.x
Subject(s) - medicine , insufflation , ventilation (architecture) , anesthesia , continuous positive airway pressure , airway , oxygenation , obstructive sleep apnea , mechanical engineering , engineering
The respiratory and circulatory conditions in high‐frequency positive‐pressure ventilation (HFPPV) in the dog and during routine surgery in man have been investigated previously. From this previous experimental and clinical experience, the insufflation‐expiratory systems could be modified for small lung ventilation (HFPPV‐infant), and the insufflation frequency‐insufflation time systems could be combined into one function. This modified HFPPV system works without any separate insufflation catheter. The respiratory and circulatory conditions during ventilation with this modified system were investigated in a series of healthy cats anaesthetized with pentobarbital. The present version of HFPPV utilizes humidified, warmed, compressed air (gas mixture) which is obtained by means of a slightly modified pneumatic part of a commercially available incubator system. By means of intermittent opening of an electronically controlled valve, this gas mixture gives an intermittent positive pressure ventilation at high frequency. It is possible to regulate alveolar ventilation during HFPPV both by means of driving‐pressure and expiratory‐resistance adjustments, as well as by regulation of the insufflation frequency and insufflation time. In the cat with normal‐compliant lungs, HFPPV gives adequate alveolar ventilation at continuous positive and low intratracheal pressures. As it has been shown that methods with continuous positive airway pressure increase arterial oxygenation and prevent airway closure, HFPPV was compared with yet another positive airway technique, continuous positive airway pressure (CPAP). The experimental studies on HFPPV and CPAP in the cat with normal‐compliant lungs revealed that HFPPV ‐ in contrast to CPAP ‐ gives adequate alveolar ventilation without circulatory interference. The electronically coupled function of insufflation frequency and time (“respirator setting”) in HFPPV was also tested, and it was shown that the arterial P o 2 is mainly influenced by the respirator driving pressure but that the arterial P co 2 and pH are additionally influenced by the respirator setting.