Cardiorespiratory Variability and Synchronization in Critical Illness

Abstract

Life support devices (e.g. heart pacemakers, ventilators, dialysis machines) are commonly thought to affect mainly their target organ system. This preliminary study attempts to determine the extent to which mechanical support of one organ system (lungs by mechanical ventilator) affects functions of other systems (heart and blood vessels). We studied changes in cardio-respiratory interactions and in dynamics of cardiovascular system during scheduled transitions (spontaneous breathing trials, SBT) between mechanical and spontaneous ventilation in critically ill patients. This initial study population consisted of 13 patients admitted to a surgical intensive care unit (ICU) following surgery, trauma or complications who were judged candidates for liberation from the ventilator. We collected continuous respiratory, cardiac (ECG), and perfusion (blood pressure and pulse oximetry) signals of mechanically ventilated patients before, during and after SBT. The data were analyzed using spectral analysis, phase dynamics and entropy measures. We found that the mechanical ventilation not only drives lung dynamics but also affects the dynamics of cardiac and vascular systems. Spontaneous cardiovascular rhythms are entrained by the mechanical ventilator and are drawn into synchrony. Sudden interruption of mechanical ventilation typically leads to rapid desynchronization. This synchronization is restored upon reinstitution of mechanical ventilation. The initial data suggest that therapies intended to support one organ system may propagate unanticipated effects to other organ systems. Moreover, sustained therapies may disturb mechanisms that promote natural synchronization and variability and thereby adversely affect recovery of normal organ system interactions.

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Document Details

Document Type
Technical Report
Publication Date
Mar 08, 2008
Accession Number
ADA500041

Entities

People

  • Anton Burykin
  • Timothy G. Buchman

Organizations

  • Washington University in St. Louis

Tags

Communities of Interest

  • Biomedical

DTIC Thesaurus Topics

  • Airway Management
  • Blood
  • Blood Vessels
  • Cardiovascular Physiological Phenomena
  • Cardiovascular System
  • Disease Attributes
  • Diseases And Disorders
  • Electrocardiography
  • Electronic Mail
  • Frequency Modulation
  • Health Services
  • Heart Rate
  • Medical Personnel
  • Power Spectra
  • Statistical Analysis
  • Therapy
  • Thorax

Fields of Study

  • Medicine

Readers

  • Cardiovascular Physiology
  • Control Systems Engineering.