Preoperative pulse rate variability and the hemodynamic response to tracheal intubation: a retrospective secondary analysis.

Individual hemodynamic responses to tracheal intubation vary considerably. We examined whether preoperative pulse rate variability (PRV), a photoplethysmography-derived surrogate of heart rate variability, is associated with this response. In this retrospective secondary analysis, 183 adults undergoing elective surgery under general anesthesia were analyzed. A 3-min photoplethysmogram was recorded in the supine, resting, unsedated state immediately before induction, and time-domain (mean pulse-to-pulse interval [mean PPI], RMSSD, and pNN50) and frequency-domain (LF power, HF power, and LF/HF) PRV indices were computed. A hemodynamic response was defined as a systolic blood pressure rise >15 mmHg, or a heart rate rise to >90 beats/min or by >30% (≥ 10% if baseline ≥90 beats/min); patients were classified as response-present or response-absent. Of 183 patients, 101 (55.2%) were response-present and 82 (44.8%) response-absent. LF/HF was higher in the response-present group (1.84 [1.32-2.60] vs 1.37 [0.78-2.44]; unadjusted P = 0.018), but no index remained significant after correction for multiple comparisons (LF/HF adjusted P = 0.109; all others adjusted P ≥ 0.301). Discrimination was limited (AUC 0.602; 95% CI 0.518-0.684). In a sensitivity analysis using a blood-pressure-only response definition, no PRV index differed significantly. After correction for multiple comparisons, no preoperative PRV index differed significantly between patients with and without a hemodynamic response to tracheal intubation. LF/HF was higher in the response-present group before correction, but the effect size was small and the discriminative performance limited. These findings do not support preoperative PRV for identifying patients at risk and are hypothesis-generating only. Trial Registration number: KCT0005840.