Abstract
Methods for mechanical cardiac support by intermittent increases in the intrathoracic pressure have recently been described. In the present study the responses of the arterial pressure waveform to mechanical ventilation with and without synchronized external chest compression (SEC) in the presence of acute ventricular failure (AVF) were evaluated by measuring the systolic pressure variation (SPV). SPV, the difference between the maximal and minimal values of systolic blood during a single positive pressure breath, consists of delta up and delta down components when systolic blood pressure during a short apnea is used as reference value. During intermittent positive pressure ventilation (IPPV) alone, AVF caused SPV to decrease significantly from 8.8 +/- 4.0 to 5.7 +/- 1.9 mm Hg, and further to 3.1 +/- 1.1 mm Hg after volume loading (P less than 0.02). The decrease in SPV was due to a significant decrease in the delta down component, whereas the delta up became the major component of the reduced SPV. The application of SEC caused significant increases in the delta down, delta up, and overall SPV during AVF without volume loading. However, during AVF with volume loading, SEC increased only the delta up component of the SPV, signifying a transient increase in the left ventricular stroke output. It is concluded that the disappearance of the delta down component of the SPV is characteristic of congestive heart failure. Analysis of the arterial waveform offers a readily available monitoring tool for the differentiation of the possible effects on increased intrathoracic pressure.(ABSTRACT TRUNCATED AT 250 WORDS)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.