Using Heart Rate Variability to Stratify Risk of Obstetric Patients Undergoing Spinal Anesthesia

Abstract

In this study, we evaluated whether point correlation dimension (PD2), a measure of heart rate variability, can predict hypotension accompanying spinal anesthesia for cesarean delivery. After the administration of spinal anesthesia with bupivacaine, hypotension was defined as systolic blood pressure </=75% of baseline within 20 min of intrathecal injection. Using the median prespinal PD2 (3.90) to form 2 groups, LO and HI, all 11 hypotensive patients were in the LO group, and all 11 patients without hypotension were in the HI group. Baseline heart rate in the LO group was 95 bpm (10.2 sd), versus 81 bpm (9.6 sd) in the HI group. PD2 shows promise as a predictor of hypotension in pregnant women receiving spinal anesthesia.

Recipes for obstetric spinal hypotension: The clinical context counts

“…[11] While a number of practical predictors such as body mass index, maternal age and baseline heart rate have shown potential, results have been conflicting and applied predominantly to elective patients. Autonomic indices such as heart rate variability have also shown promise, [12] but have yet to be translated into a practical clinical tool. Given the high incidence of hypotension, [1,9] research in this area should focus on predicting which patients will have severe hypotension, where outcomes relating to maternal and fetal safety are more likely to be affected.…”

Correlation between heart rate variability and haemodynamic fluctuation during induction of general anaesthesia: comparison between linear and non‐linear analysis*

“…While frequency-domain measures of HRV, such as spectral analysis, focus on the status of cardiac autonomic activity, it is proposed that non-linear indices may provide insight into the overall structure of the heart rate regulating system. Although it was reported that pre-operative point dimension correlation (PD2), as a non-linear index of HRV, predicted hypotension after spinal anaesthesia [10], there is no previous report examining the correlation between non-linear index of HRV and circulatory response to induction of general anaesthesia.The MemCalc method, which is a combination of the maximum entropy method for spectral analysis and the non-linear least squares method for fitting analysis (Tarawa, Suwa Trust, Tokyo, Japan), has recently been developed [11,12]. This method enables us to estimate reliable HRV from a series of RR intervals over 30 s and recognises the abnormal RR interval of premature beats or artefacts, including noise, and removes it automatically.…”

La variabilité de la fréquence cardiaque et de la tension artérielle comme indicateurs du bloc sensitif lors de l’analgésie péridurale pour le travail obstétrical

“…Several studies have used analysis of HR variability to predict hypotension after spinal anesthesia, [15][16][17] to prevent hypotension prior to spinal anesthesia, 18 to predict morbidity and mortality from arrhythmias, 19,20 as a predictor of mortality in head trauma patients, 21,22 and as an index of survival in the critically ill patients. [22][23][24] The results presented here provide another example of how analyses of HR and BP variability could eventually be used to assess the degree of somatosensory blockade while monitoring autonomic changes that might compromise hemodynamic stabil-ity in our patients.…”