Correlation Analysis of Environmental Noise in the Intensive Care Unit with the Incidence of Delirium and Heart Rate Variability in Patients After Percutaneous Coronary Intervention

Abstract

Objective: To investigate the correlation between environmental noise in the intensive care unit (ICU) and the occurrence of delirium and heart rate variability (HRV) in patients after percutaneous coronary intervention (PCI), thereby providing a clinical basis for optimizing the ICU environment, reducing delirium incidence, and improving patient prognosis. Methods: We enrolled 132 patients admitted to the ICU after PCI between January 2023 and January 2024. Environmental noise was continuously monitored for 72 h. We assessed delirium using the Nursing Delirium Screening Scale, and HRV parameters, including the standard deviation of normal-to-normal RR intervals (SDNN), the root mean square of successive differences between adjacent RR intervals (rMSSD), low-frequency power (LF), and high-frequency power (HF), were recorded via dynamic electrocardiography. We evaluated data using Pearson correlation analysis and logistic regression analysis. Results: The mean ICU noise level was 51.74 ± 4.82 dB, and the incidence of delirium was 35.61%. Noise levels were significantly higher in the delirium group than in the non-delirium group (P < 0.05). Pearson analysis revealed that noise levels were negatively correlated with SDNN, rMSSD, and HF (r = −0.429 to −0.356, P < 0.01), and positively correlated with LF (r = 0.398, P = 0.001). Multivariate logistic regression analysis identified ICU environmental noise [odds ratio (OR) = 1.171], age (OR = 1.060), and postoperative pain score (OR = 1.288) as independent risk factors for delirium (P < 0.05). Conclusion: Environmental noise levels in the ICU after PCI generally exceed recommendations. High noise levels are associated with abnormal HRV parameters and an increased risk of delirium. Optimizing the ICU acoustic environment may help reduce the incidence of delirium and improve patient outcomes.