Respiratory variation of systolic and diastolic time intervals within radial arterial waveform: a comparison with dynamic preload index.

Abstract Background A blood pressure (BP) waveform contains various pieces of information related to respiratory variation. Systolic time interval (STI) reflects myocardial performance, and diastolic time interval (DTI) represents diastolic filling. This study examined whether respiratory variations of STI and DTI within radial arterial waveform are comparable to dynamic indices. Methods During liver transplantation, digitally recorded BP waveform and stroke volume variation (SVV) were retrospectively analyzed. Beat-to-beat STI and DTI were extracted within each BP waveform, which were separated by dicrotic notch. Systolic time variation (STV) was calculated by the average of 3 consecutive respiratory cycles: [(STI max − STI min )/STI mean ]. Similar formula was used for diastolic time variation (DTV) and pulse pressure variation (PPV). Receiver operating characteristic analysis with area under the curve (AUC) was used to assess thresholds predictive of SVV ≥12% and PPV ≥12%. Results STV and DTV showed significant correlations with SVV ( r = 0.78 and r = 0.67, respectively) and PPV ( r = 0.69 and r = 0.69, respectively). Receiver operating characteristic curves demonstrated that STV ≥11% identified to predict SVV ≥12% with 85.7% sensitivity and 89.3% specificity (AUC = 0.935; P P Conclusion Respiratory variations of STI and DTI derived from radial arterial contour have a potential to predict hemodynamic response as a surrogate for SVV or PPV.