Application III: A Study on Intermittent Mandatory Ventilation (IMV)

Abstract

Intermittent mandatory ventilation (IMV) is a ventilatory mode with a complex pattern of breaths. An IMV-cycle begins with a mandatory breath (MB) imposed on the patient by the ventilator, which is followed by a sequence of spontaneous breaths (SB). Since pleural pressure during inspiration rises in the MB and falls in the SB, we assumed that the gas exchange in mandatory breaths is different from that in spontaneous breaths. It is difficult, however, to investigate this hypothesis quantitatively by comparing the mean values of a period of IMV with the mean values of a period of CPPV and of CPAP. Mandatory and spontaneous breaths have to be compared separately. Consequently, we had to use methods suitable for a breath-by-breath analysis. In other words, this study demonstrates special advantages of the measuring system introduced in the present volume. We are able to show that each single breath is investigated separately and the results of the breaths of a certain type i.e., spontaneous and mandatory breaths — can subsequently be grouped. Moreover, the comparison of IMV with CPAP provides the opportunity to demonstrate the measuring system as it is applied for spontaneous breathing.