Septic shock was associated with significantly reduced heart rate variability (p=0.007), diastolic blood pressure variability (p=0.003), and baroreflex control (p=0.003) compared to controls.
Observational (n=26)
The onset of septic shock is characterized by impaired sympathetic modulation on the heart and vessels despite high circulating catecholamines, suggesting central autonomic regulatory impairment contributes to circulatory failure.
p-value: p=0.007
The autonomic cardiovascular control was investigated in 10 patients with septic shock, 10 patients with sepsis syndrome, and six tilted healthy subjects. Overall variability, high- and low-frequency components (AUC, HF, and LF, beats/min(2)/Hz or mm Hg(2)/Hz) from heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressures spectra were obtained from 5-min recordings. LF(HR)/HF(HR) and the square root of LF(SBP)/LF(HR) (alpha) were used as indices of sympathovagal interaction and baroreflex control of the heart, respectively. Compared with tilted control subjects and patients with sepsis syndrome, septic shock is characterized by reduction in: (1) HR variability, i.e., decreased AUC(HR) (p = 0.007), LF(HR) (p = 0.002), and LF(HR)/HF(HR) (p = 0.0002); (2) DBP variability, i.e., decreased AUC(DBP) (p = 0.003) and LF(DBP) (p = 0.001), (3) alpha (p = 0.003). In septic shock, LF(HR)/HF(HR), alpha, and LF(DBP) correlated with mean blood pressure (r = 0.67, p = 0.04, r = 0.64, p = 0.03, and r = 0.88, p = 0.0008, respectively), and with plasma norepinephrine levels (r = -0.65, p = 0.03, r = -0.79, p = 0.006, and r = -0.69, p = 0.03, respectively). In conclusion, onset of septic shock is characterized by high concentrations of circulating catecholamines but impaired sympathetic modulation on heart and vessels, suggesting that central autonomic regulatory impairment contributes to circulatory failure.
Annane et al. (Sun,) conducted a observational in Septic shock and sepsis syndrome (n=26). Septic shock vs. Sepsis syndrome and tilted healthy subjects was evaluated on Heart rate variability (AUC(HR)), diastolic blood pressure variability (AUC(DBP)), and baroreflex control (alpha) (p=0.007). Septic shock was associated with significantly reduced heart rate variability (p=0.007), diastolic blood pressure variability (p=0.003), and baroreflex control (p=0.003) compared to controls.