Journal of medical engineering & technology
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Respiratory variation in the systemic arterial blood pressure tracing is predictive of the change in cardiac output following volume administration. However, significant inter-individual variability exists. Animal data suggest that systemic arterial respiratory variation loses its predictive ability in the setting of right ventricular failure. ⋯ The correlation between SPoR(pulmonary) and SPoR(radial) was stronger than the correlation between either measure of respiratory variation and any of the ventilatory parameters (r = 0.342, p < 0.001). Respiratory variation in the pulmonary arterial tracing does not appear to be closely related to ventilatory parameters and is more closely related to systemic arterial respiratory variation, a well-validated estimate of volume status. The observed respiratory variation in the pulmonary arterial pressure tracing may be related to cyclical changes in pre-load or after-load that occur with mechanical ventilation and may affect the predictive power of systemic arterial respiratory variation.