Does heart rate variability predict hypotension and bradycardia after induction of general anaesthesia in high risk cardiovascular patients?*

Abstract

SummaryThis study investigated whether heart rate variability predicts haemodynamic events in high risk patients, defined as Revised Cardiac Risk Index score = 3, scheduled for general anaesthesia. Fifty patients underwent baseline measurement of heart rate variability and were then assigned according to haemodynamic events (hypotension or bradycardia) after standardised induction of anaesthesia into 'stable' (n = 39) and 'unstable' patients (n = 11). Unstable patients had significantly lower baseline total power. Total power < 500 ms 2 .Hz )1 was associated with high sensitivity and specificity for the prediction of hypotension or bradycardia. Prospectively, 29 patients with total power < 500 ms 2 .Hz )1 were compared with 21 patients with total power > 500 ms 2 .Hz )1 . Differences were found in the lowest mean arterial pressure and heart rate after induction of anaesthesia. We conclude that the pre-operative total power of heart rate variability in high risk patients may indicate the occurrence of haemodynamic events with high sensitivity and specificity. Heart rate variability may be a suitable tool to identify patients at high risk of a haemodynamic event and may be used to indicate need for intensive monitoring and, perhaps, prophylactic treatment. Patients with underlying cardiovascular disease are at high risk of peri-operative cardiovascular events and death [1,2]. Adverse events during anaesthesia and surgery may increase the risk further in this patient population. Specifically, following induction of general anaesthesia, hypotension and bradycardia are often observed and may lead to insufficient organ perfusion and ischaemic events [3][4][5]. Haemodynamic parameters are controlled, to some extent, by the autonomic nervous system. The activity of the autonomic nervous system is reflected in the heart rate variability (HRV) [6][7][8]. Several authors have demonstrated depressed long-term HRV in patients with underlying cardiovascular disease [9][10][11] and HRV has proved to be highly predictive for cardiovascular morbidity and mortality in these patients [12][13][14]. Recently, short-term HRV analysis (5 min) has been shown to be a reliable tool to predict hypotension after spinal anaesthesia [15,16]. The low to high frequency ratio (LF ⁄ HF) was demonstrated to be a highly sensitive parameter to predict hypotension [17] and LF ⁄ HF-guided prophylactic therapy was able to prevent hypotension [18]. Only preliminary data have been published on the incidence of hypotension or bradycardia after induction of general anaesthesia in patients with underlying autonomic dysfunction [19,20]. A retrospective subgroup analysis of a small number of patients with diabetes demonstrated that pre-operative depression of sympathetic and parasympathetic activity was correlated with a significantly greater incidence of hypotension after induction of anaesthesia. However, these results were not confirmed prospectively.This study was designed to investigate the predictive power of HRV in patients with underlying cardiovascu...

Sympathetic withdrawal is associated with hypotension after hepatic reperfusion

“…In previous studies, total HRV power has been found to be associated with the development of hypotension during general anesthesia [15,32]. Hanss et al [15] reported that preoperative total power of HRV is associated with the occurrence of hypotension and bradycardia during anesthesia, and that HRV may be a suitable tool to identify preoperatively patients at high risk of hemodynamic events.…”

“…These observations suggest that there is a relationship between cardiovascular autonomic control and hemodynamic stability during liver transplantation surgery. Furthermore, cardiovascular autonomic indices derived from power spectral analysis, such as the ratio of low frequency power to high frequency power (LF/HF) or the total power of heart rate variability (HRV), have attracted attention with regard to their potential use in predicting hypotensive episodes in patients undergoing anesthesia or hemodialysis [13][14][15]. However, the association between cardiovascular autonomic indices and reperfusion-related hemodynamic instability during liver transplantation remains to be established.…”

Use of heart rate variability analysis to determine the risk of cardiac ischaemia in high‐risk patients undergoing general anaesthesia

“…The predictive value of TP for cardiac ischaemia was superior compared with LF ⁄ HF. Previous data from our group obtained in patients undergoing spinal anaesthesia showed that a threshold value of LF ⁄ HF > 2.5 was best able to predict hypotension with high sensitivity and specificity [15][16][17]. We tested a threshold value of LF ⁄ HF > 2.5 for prediction of cardiac ischaemic events and length of hospital stay in this study.…”

“…One hundred patients participated in the study. We have previously published results concerning the use of TP for prediction of intra-operative hypotension in the same group of patients [17]. The patients were followed during the postoperative period and for 1 year after discharge as part of our investigation.…”

“…The patients were followed during the postoperative period and for 1 year after discharge as part of our investigation. Demographic data and baseline haemodynamic data have been published [17].…”