Continuous, on-line, real-time spectral analysis of SAP signals during cardiopulmonary bypass

M. W. Yang, T. B.J. Kuo, S. M. Lin, K. H. Chan, S. H.H. Chan

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)


We communicated the application of continuous, on-line, real-time power spectral analysis of systemic arterial pressure (SAP) signals during cardiopulmonary bypass when the heart was functionally but reversibly disconnected from the blood vessels. Based on observations from 15 cases of successfully completed coronary artery bypass grafting procedures, we found that the very low (0.00-0.08 Hz), low (0.08-0.15 Hz)-, high (0.15-0.25 Hz)-, and very high (0.801.60 Hz) frequency components of SAP signals exhibited differential changes before, during, and after cardiopulmonary bypass. In particular, the very low-frequency component, which purportedly represents the contribution of vasomotor activity to SAP, presented only a mild decrease in power during hypothermic cardioplegia. Interestingly, the total peripheral resistance also manifested only a slight reduction during the same period. On the other hand, the low-, high-, and very high frequency components were essentially eliminated. These results unveiled an active role for the blood vessels in the maintenance of SAP during cardiopulmonary bypass, possibly as a result of a maintained vasomotor tone as reflected by the sustained very low frequency component of the SAP signals.

Original languageEnglish
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Issue number6 37-6
Publication statusPublished - 1995
Externally publishedYes


  • cardioplegia
  • coronary artery bypass grafting
  • power spectrum
  • systemic arterial pressure
  • vasomotor tone

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)


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