Early heart rate variability evaluation enables to predict ICU patients' outcome.

Heart rate variability (HRV) is a mean to evaluate cardiac effects of autonomic nervous system activity, and a relation between HRV and outcome has been proposed in various types of patients. We attempted to evaluate the best determinants of such variation in survival prediction using a physiological data-warehousing program. Plethysmogram tracings (PPG) were recorded at 75 Hz from the standard monitoring system, for a 2 h period, during the 24 h following ICU admission. Physiological data recording was associated with metadata collection. HRV was derived from PPG in either the temporal and non-linear domains. 540 consecutive patients were recorded. A lower LF/HF, SD2/SD1 ratios and Shannon entropy values on admission were associated with a higher ICU mortality. SpO2/FiO2 ratio and HRV parameters (LF/HF and Shannon entropy) were independent correlated with mortality in the multivariate analysis. Machine-learning using neural network (kNN) enabled to determine a simple decision tree combining the three best determinants (SDNN, Shannon Entropy, SD2/SD1 ratio) of a composite outcome index. HRV measured on admission enables to predict outcome in the ICU or at Day-28, independently of the admission diagnosis, treatment and mechanical ventilation requirement.Trial registration: ClinicalTrials.gov identifier NCT02893462.

Predictors of residual pulmonary vascular obstruction after pulmonary embolism: Results from a prospective cohort study.

BACKGROUND: We aimed to determine the prevalence of residual pulmonary vascular obstruction (RPVO) after symptomatic pulmonary embolism (PE) and to identify risk factors for RPVO. METHODS: On the basis of a prospective cohort of patients with a documented symptomatic venous thromboembolism, we included patients who had an acute PE and underwent a ventilation/perfusion lung scan at 3 to 24 months during the follow-up after PE. RPVO score was assessed for each patient. Initial pulmonary vascular obstruction at PE diagnosis was also assessed when available. Univariable and multivariable analyses were performed with preselected data to identify predictors for persistent defect defined as RPVO ≥ 5%. RESULTS: Among the 537 included patients, 278 (51.8%) had RPVO ≥ 5%, and 191 (35.6%) had RPVO ≥ 10%. In primary multivariate analysis on overall population, age ≥ 65 years (odds ratio [OR] 2.25, 95% CI, 1.45-3.52) and chronic respiratory failure (OR 3.19, 95% CI, 1.22-10.04) were independent predictors of RPVO ≥ 5%. In secondary multivariate analysis restricted to 256 patients with available initial pulmonary vascular obstruction score at index PE (IPVO), age ≥ 65 years (OR 2.78, 95% CI, 1.41-5.53), unprovoked PE (OR 2.11, 95% CI, 1.11-4.07) and IPVO ≥ 20% (OR 2.94, 95% CI, 1.68-5.20) were found to be independent risk factors for RVPO ≥5%. CONCLUSION: In this selected population of patients with an acute PE, age ≥ 65 years, unprovoked PE and IPVO ≥ 20% at PE diagnosis appeared to be risk factors for residual pulmonary vascular obstruction measured at three to 24 months.