[Relationship between heart rate variability and serum levels of thyroid hormones, cortisol and prognosis in patients with systemic inflammatory response syndrome].

OBJECTIVE

To explore the relationship of autonomic nerve system regulation function in patients with systemic inflammatory response syndrome (SIRS) to hypothalamo-pituitary-adrenal axis and to find useful markers to predict the prognosis of patients with SIRS.

METHODS

Acute physiology and chronic health evaluation II (APACHE II) and multiple organ dysfunction syndrome (MODS) scores were obtained and heart rate variability (HRV) was analyzed with both time-domain and frequency-domain methods. The serum levels of thyroid hormone and cortisol (COR) were measured by radio-immunoassay.

RESULTS

(1) The patients with SIRS showed significantly higher APACHE II scores and MODS scores but lower HRV when compared with the non-SIRS patients and control group (P<0.05 or P<0.01). In addition, in the SIRS group, the non-survivors were found to have statistically higher APACHE II and MODS scores as well as lower HRV than the survivors (all P<0.01). (2) Multiple regression analysis revealed that there was a negative correlation between the outcome of the patients and standard differentiation of NN interval (SDNN), and there was a positive correlation between the outcome of the patients and APACHE II and MODS scores (P<0.01 and P<0.05). The correction rates of prediction in good or bad outcome were 81.1% and 74.5%, respectively. SDNN<or=55 ms may be the prognostic threshold value, and the sensitivity, specification, positive and negative prediction values were 76.2%, 76.7%, 90.4% and 52.6% respectively. (3) The patients with SIRS showed lower thyroid hormone levels of triiodothyronine(T3), tetraiodothyronine(T4), thyroid stimulating hormone(TSH), and higher concentration of COR compared with the non-SIRS patients and healthy controls, and they were correlated with the prognosis of the patients (P<0.05 or P<0.01). (4) In the SIRS group there were positive correlations between concentrations of T3, TSH and HRV, and opposite results were also obtained between the HRV and the concentration of COR, showing negative correlation (P<0.05 or P<0.01). (5) In the death group, there were positive correlations between concentrations of T3, T4, TSH and HRV (P<0.01 or P<0.05). Also in this group, there were positive correlations between MODS scores and COR, but negative correlation between COR and SDNN (P<0.05 or P<0.01).

CONCLUSION

Evidently the neuroendocrine system exerts significant influences on the severity of disease, function of organs and prognosis. SDNN, concentration of COR, APACHE II and MODS scores were the useful indexes to evaluate the prognosis of the patients with SIRS.