Assessment of neuro-cardiovascular uncoupling in acute brain injury patients

Acute brain injury results in decreased heart rate variability (HRV) and baroreflex function. The aim of the study was a longitudinal investigation of heart rate dynamics and relation with the severity of neurological dysfunction and outcome. Metrics used were performed in 20 consecutive brain injured patients and included power spectral analysis, approximate entropy (ApEn) and transfer function (TF), as a measure of baroreflex sensitivity. There was no significant difference between survivors with different Glasgow Outcome Score (GOS = 2-5), while the six non-survivors (brain dead) with GOS = 1 had decreased variability, ApEn and TF values in relation with survivors. Mean and minimum values of different frequency components of the power spectrum were significantly associated with survival.