Perioperative hypoxaemia early warning based on high-frequency waveform fusion and deep learning

Objective.The accurate prediction of impending intraoperative hypoxaemia events is paramount for patient safety. Current models relying on structural parameters exhibit limitations, including low sampling frequency, weak temporal coherence, and high data attrition rates. Consequently, long-term sequence, high-frequency waveform data are utilised in this study to construct a deep learning-based hypoxaemia prediction model, by which conventional shortcomings are addressed whilst predictive accuracy and robustness are enhanced.Approach.Respiratory, blood oxygenation, and electrocardiogram waveforms were extracted from the VitalDB database. Two processing methods were employed: extraction of waveform-derived variables to construct numerical datasets; and utilisation of the Gramian Angular Summation Field (GASF) and the four-quadrant matrix method to construct image-based datasets. Through multiple dataset construction methods, five datasets were constructed. An LSTM algorithm was employed, using a 5 min learning window and prediction windows ranging from 1 to 13 min, to conduct a comprehensive performance evaluation.Main results.Optimal performance was achieved by all models within a one-minute prediction window. Highly competitive accuracy (0.932), AUC (0.953), and stability (maximum AUC variance 0.067) were demonstrated by the 'Multimodal image model', whilst the poorest performance was exhibited by the 'structured only model'. Moreover, compared to singlemodal models, multimodal models incorporating structured parameters yield only marginal improvements. Consequently, singlemodal data derived solely from raw waveforms are suggested as sufficient for prediction requirements, by which greater application potential is held due to enhanced computational efficiency.Significance.This study systematically demonstrated the significant advantages of high-frequency waveform data. Results indicate that waveform processing methods based on the GASF and the four-quadrant matrix approach can effectively enhance model stability and performance. Furthermore, the singlemodal model relying solely on waveform data, excluding structured parameters, can meet clinical prediction requirements while reducing computational costs. This study provides novel data structures and methodologies for perioperative hypoxaemia prediction.