Autonomic nervous system monitoring in intensive care as a prognostic tool. Systematic review

Abstract

ObjectiveTo present a systematic review of the use of autonomic nervous system monitoring as a prognostic tool in intensive care units by assessing heart rate variability.MethodsLiterature review of studies published until July 2016 listed in PubMed/Medline and conducted in intensive care units, on autonomic nervous system monitoring, via analysis of heart rate variability as a prognostic tool (mortality study). The following English terms were entered in the search field: ("autonomic nervous system" OR "heart rate variability") AND ("intensive care" OR "critical care" OR "emergency care" OR "ICU") AND ("prognosis" OR "prognoses" OR "mortality").ResultsThere was an increased likelihood of death in patients who had a decrease in heart rate variability as analyzed via heart rate variance, cardiac uncoupling, heart rate volatility, integer heart rate variability, standard deviation of NN intervals, root mean square of successive differences, total power, low frequency, very low frequency, low frequency/high frequency ratio, ratio of short-term to long-term fractal exponents, Shannon entropy, multiscale entropy and approximate entropy.ConclusionIn patients admitted to intensive care units, regardless of the pathology, heart rate variability varies inversely with clinical severity and prognosis.

Heart rate variability as a marker of recovery from critical illness in children

“…[1–3], The resultant disruption in systemic homeostasis due to ANS dysregulation or dysfunction has been associated with organ dysfunction, increased illness severity, and poor outcomes. [4–8] The most common method of objectively assessing ANS dysregulation is through measurement of HRV, which reflects the normal, physiologic alterations in the intervals in time between consecutive heart beats that occur when there is balance of sympathetic and parasympathetic inputs on the electrical conduction system of the heart. [9].…”

Heart Rate Variability Using The Analgesia Nociception Index as A Predictor of Illness Severity and Mortality in Critically Ill Patients with COVID-19.

“…The high-frequency component of HRV and energy level (total power) were recorded using the analgesia nociception index monitor (ANI monitor, MDoloris Medical Systems, Lille, France). ANI monitor provides a number from 0 to 100, which is a percentage estimate of the balance between the parasympathetic nervous system (HFnu) and the added activity of the different spectral components, i.e., the total power or energy [7][8][9].…”

“…Heart rate variability (HRV) refers to the variation between one heartbeat and the next, a process that is in uenced by different components of the ANS, including breathing (respiratory sinus arrhythmia) and other physiological factors [7][8][9].…”

“…To do this, it performs a spectral analysis of the different spectral bands of HRV taken from a patient's electrocardiogram (ECG). The high-frequency component (HF between 0.15 Hz and 0.4 Hz) is mediated by the parasympathetic nervous system or vagal tone; the low-frequency component (LF between 0.15 to 0.04 Hz) is mainly in uenced by barore ex mechanisms and the sympathetic nervous system; and, lastly, the very low-frequency component (VLF between 0.04 to 0.003 Hz) is in uenced by thermoregulation and different hormonal factors [9]. The total power of the RR interval variability encompasses the sum of all spectral bands and represents the total activity of the ANS [7][8][9].…”

“…There is a strong scienti c evidence that demonstrates the usefulness of monitoring HRV in critically ill patients [9,10]. Many papers conclude that critically ill patients with lower HRV and lower total activity of the ANS (total power) have a greater number of complications and higher mortality [9][10][11][12][13].…”