The Heart Rate Variability And Prognosis Evaluation In Critical Illness

ObjectiverWe used heart rate variability( HRV) analysis to meaure and judge critically ill patients' prognosis .Methods:All the patients were divided into three groups based on Acute Physiology-and Chronic Health Evaluation(APACHE) II, 0?, 10?9, >20.And we computed predicted death rates(R), the R > 0.5 is belong to one group,R<0.5 fall to another.Then 24-hour holter were recorded within 24 hours .To compute 5-miniute short-term and 24-hour long-term HRV and to compare the deference among the groups.Logistic regression was used to observe the relation between the indexes of HRV and the prognosis of the patients.Results: The indexes of short-term HRV: VLF, LF, LF/HF, RR5 and the indexes of long-term HRV: SDNN, SDANN were significantly decreased in the patients with APACHE II score >20 or R>0.5. The mean HRs were higher in the patients with APACHE II score >20 or R>0.5. besides the indexs above-mentioned,rMSSD is also decreased in death group. But there was no defference were found in the vagal mediated indexes of HRV: HF, rMSSDs, PNN50, among the groups.To compute the risk (Pr) of fatality with the logistic regress equation.In the evaluation of prognosis,the sensitivity of Pr >0.5 and APACHE II score >20 were higher than R>0.5,the specificity of Pr >0.5 and R>0.5 were higher than APACHE II score >20.Conclusion:When the APACHEII score>20 or R>0.5,the indexes of short-term HRV, VLF,LF,LF/HF,RR5 and the indexes of long term HRV,SDNN,SDANN significantly decreased.The indexes of above significantly decreased in the deaths than that in survivors,rmssd decreased too.The mean HRs were higher in the patientswith APACHE II score >20, R>0.5 and the deaths.In the indexes of HRV,HR and3LF/HF have closely relation to prognosis,which combined with APACHE II system can improve the sensitivity and specificity of their prognosis evaluation.