Associação entre variabilidade da frequência cardíaca e mortalidade em 14 dias em pacientes com traumatismo cranioencefálico submetidos à cirurgia descompressiva

Abstract

Introduction and rationale: Traumatic brain injury (TBI) is the leading cause of death and sequelae in children and young adults in Western industrialized countries. Heart rate variability has been a widely used predictor of mortality because it is directly related to the autonomic system and serves as a prognostic marker in various conditions such as trauma, diabetes, sepsis, myocardial infarction, and hemorrhagic stroke. A recent study found that heart rate variability (HRV) in patients undergoing decompressive craniectomy was associated with prognosis; however, the association in patients undergoing neurotraumatic surgery in addition to decompressive craniectomy has not yet been evaluated. Objective: To assess whether HRV is associated with mortality within 14 days. Method: Patients ≥18 years old who underwent drainage surgery for intracerebral hematomas following traumatic brain injury at the Dr. João Lúcio Pereira Machado Hospital and Emergency Room were recruited from October 2023 to June 2024. Cardiac autonomic behavior was assessed by analyzing heart rate variability (HRV) in the supine position for 5 min. RR interval data will be captured by a heart rate monitor (Polar RS800, Polar, Kemple, Finland). The parameters analyzed will be in the time domain, frequency domain, and nonlinear domain, calculated using Kubios 3.0 software (University of Kuopio, Kuopio, Finland). Results: The RR interval (RRi) was significantly longer in the survivor group (774 ± 180 ms) compared to the non-survivor group (643 ± 130 ms; p = 0.028; effect size = -0.90). Similarly, the mean heart rate showed a statistically significant difference, being lower in survivors (80.8 ± 18.6 bpm) compared to non-survivors (96.6 ± 18.7 bpm; p = 0.037; effect size = 0.87). Conclusion: This study showed that only the RR interval and mean heart rate were significantly associated with early mortality in patients with severe traumatic brain injury. These results suggest that simple measurements, obtained directly from multiparameter monitors, may have greater clinical applicability than more complex indices of heart rate variability in this scenario.