Prediction of perioperative complications in colorectal cancer via artificial intelligence analysis of heart rate variability

Figure 1 Heart rate variability in a normal and abnormal state. A: A smart monitoring device for the collection of heart rate variability data; B: Poincaré scatter diagram in a relaxed and stressed state; C and D: Trend chart of time-domain parameters indicating the difference 24 hours before the operation to 3 days after the operation; E and F: Power spectral density analysis of the frequency domain indicates the difference between the non-perioperative complication group and the perioperative complication group. NPC: Non-perioperative complication; PC: Perioperative complication; HF: High-frequency; LF: Low-frequency.