Respiratory variation of systolic and diastolic time intervals within radial arterial waveform: a comparison with dynamic preload index.
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: [(STImax- STImin)/STImean]. 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< .001). DTV ≥11% identified to predict SVV ≥12% with 71.4% sensitivity and 85.7% specificity (AUC = 0.829; P< .001). STV ≥12% and DTV ≥11% identified to predict PPV ≥12% with an AUC of 0.881 and 0.885, respectively.


CONCLUSIONS
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.
Department of Anesthesia and Pain Medicine, Laboratory for Cardiovascular Dynamics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
Ji Hyun
JH
Park
Department of Anesthesia and Pain Medicine, Laboratory for Cardiovascular Dynamics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea. Electronic address: kshwang@amc.seoul.kr.
Gyu-Sam
GS
Hwang
D000328:Adult; D003971:Diastole / Q000502:physiology*; D005260:Female; D006801:Humans; D016031:Liver Transplantation; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000706:statistics & numerical data; D017534:Radial Artery / Q000502:physiology*; D012121:Respiration, Artificial; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013318:Stroke Volume / Q000502:physiology; D013599:Systole / Q000502:physiology*; D013995:Time
Dynamic index; Respiratory variation; Systolic and diastolic time interval