Clinical physiology (Oxford, England)
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Clinical Trial
The static pressure-volume relationship of the respiratory system determined with a computer-controlled ventilator.
The pressure-volume relationship of the respiratory system offers a guideline for setting of ventilators. The occlusion method for determination of the static elastic pressure-volume (Pel(st)/V) relationship is used as a reference and the aim of the study was to improve it with respect to time consumption and precision of recording and analysis. The inspiratory Pel(st)/V curve was determined with a computer-controlled ventilator using its pressure and flow sensors. ⋯ The difference in compliance between measurements was 1.6 +/- 1.3 ml cmH2O(-1) or 1.2 +/- 0.9%. The position of the curve differed between measurements by 15 +/- 10 ml or by 1.1 +/- 0.9%. In a patient with acute lung injury the feasibility of applying a numerical method for a more detailed description of the Pel(st)/V curve was illustrated.
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Comparative Study
Finger-to-brachial comparability of 'modelflow' stroke volume improves after pulsewave reconstruction.
Modelflow is a method that determines stroke volume (SV) from central or peripheral continuous blood pressure signals. Pulsewaves are changed along the arterial tree; distortion occurs as the mean pressure level gradually declines. These changes might jeopardize the determination of SV from a distal measurement site. ⋯ RTF had no additional effect. We concluded that the FIN-to-BAP comparability can be increased by brachial reconstruction techniques, which correct for the pressure gradient. This can be adequately performed without additional measurements, allowing its application to measurements already taken.