Background: We tried to determine whether the severity of additional mean arterial pressure (MAP) elevation after endotracheal intubation during general anesthesia could be predicted with preanesthetic recurrence quantification analysis of heart rates in hypertensive and normotensive patients.
Methods: Twenty-four newly diagnosed hypertensive patients and 34 normotensive patients were included. We defined ΔMAP = maximal mean MAP after endotracheal intubation – average MAP before general anesthesia. We classified each of the hypertensive and normotensive patients into mild (ΔMAP ≤ 35 mmHg [median value of ΔMAP in the hypertensive patients]) and severe group (ΔMAP > 35 mmHg). Using preanesthetic RR interval data, we calculated classical linear and non-linear indices of RR interval dynamics, and performed recurrence quantification analysis to calculate three preanesthetic recurrence indices, percentage of recurrence (%REC), percentage of determinism (%DET), and maximal length of recurrence (Lmax).
Results: In the hypertensive patients, all preanesthetic classical indices showed no significant difference between the mild and severe group and showed no significant linear correlation with the ΔMAP. However, the Lmax was significantly higher in the severe than in the mild group (16.10 ± 3.79 vs. 7.90 ± 0.73, P < 0.005) and, moreover, linearly correlated with the ΔMAP (r = 0.671, P = 0.001). In the normotensive patients, all preanesthetic classical and recurrence indices showed no significant difference between the two groups.
Conclusion: In hypertensive patients, the severity of additional MAP elevation after tracheal intubation during general anesthesia can be predicted by the preanesthetic recurrence quantification analysis of heart rates.