Regular low frequency cardiac output oscillations observed in critically ill surgical patients

Abstract

A serendipitous finding during development of an automated “electronic flow chart” system to gather data on ICU patients [1] was the observation of low frequency oscillations in blood pressure that were not explained by systematic variability in the environment. [2] This finding has since been confirmed by others. [3,4] In the present report, hemodynamic data for critically ill surgical patients was continuously collected and visualized on a computer workstation to search for patterns not noted by standard monitoring. With this system, we observed low‐frequency periodic oscillations in the cardiac output of ten patients, with regular periodicities of 4 to 280 minutes (average = 34 minutes). The mortality rate in these patients was 40%, while the mortality was only 10.8% in 83 similarly monitored intensive care unit (ICU) patients who did not develop regular oscillations in cardiac output. Interestingly, these oscillatory patterns appear to be associated with inadequate resuscitation of increased metabolic rates. The mathematical definition of “chaos” refers to irregular behavior that appears to be random but is actually deterministic. [5] A surprising finding concerning transitions between states of apparent randomness and order in nonlinear systems is that many systems become more organized after being disturbed. Chaotic behavior in biological systems may represent a normal physiologic state, while the loss of chaotic behavior may herald a pathophysiologic state. [6] The mechanism of the regular low frequency oscillations in cardiac output remains to be determined, but the high mortality rate suggests that it is a pathophysiologic marker, perhaps due to inadequate oxygen delivery in under‐resuscitated shock. © 1997 John Wiley & Sons, Inc.

Risk evaluation of diabetes mellitus by relation of chaotic globals to HRV

“…Spectral entropy and; later the new “chaotic global” techniques attempt to overcome this disadvantage; avoiding the vulnerability to thin data. Such computations are useful in monitoring surgical patients under anaesthesia ; or unable to communicate distress as in sleep apnea or dyspnea .…”

“…Especially, long‐range correlations a key feature of complex systems . Chaotic behavior in biological systems may indicate normal physiological status, whereas loss of chaotic tendancies may be a pathophysiological marker . The mechanism of the regular low‐frequency oscillations in cardiac output remains to be assessed conclusively.…”

Report of a Case Series of Ultra Low-Frequency Oscillations in Cardiac Output in Critically Ill Adults with Sepsis, Systemic Inflammatory Response Syndrome, and Multiple Organ Dysfunction Syndrome

“…We serendipitously discovered ultra-low frequency periodic oscillations in cardiac output (ULF-CO) occurring in the physiologic time series of critically ill adults during our testing of software to facilitate continuous physiological monitoring (18). In this case series report, we present the qualitative and quantitative dynamics of ULF-CO, as well as associated clinical conditions and outcomes of these critically ill patients.…”

Oscillations in Cardiovascular Function During Acute Hypoxia in the Newborn Piglet Are Associated With Less Neurological Damage and Occur More Frequently in Females

“…Our own data have shown that serum cortisol concentrations are also related to neurologic damage and cardiovascular function, an effect which may be mediated via the activity of the sympathetic nervous system (SNS) (2). Several studies have reported that the cardiovascular system can exhibit an oscillating response during periods of stress, such as hypoxia and cerebral ischemia (3)(4)(5)(6). Oscillations in cardiovascular function occur at different frequencies.…”

“…In comparison, type-3 waves are slower with a cycle period of 10 to 160 s. They have been observed in the presence of hypoxia, hemorrhage, cold, endotoxic shock, and increased intracranial pressure (4). Type-3 waves in blood pressure have been reported to occur in neonatal rats during acute hypoxia (5).…”