An interaction effect analysis of thermodilution-guided hemodynamic optimization, patient condition, and mortality among successful cardiopulmonary resuscitation patients

Abstract

Background Post-cardiac arrest syndrome and target temperature management have an influence on hemodynamics in a complex way. Proper hemodynamic monitoring is necessary among post-cardiac arrest patients. The aim of our study was to investigate the effects of PiCCO™-guided hemodynamic management on short- and long-term mortality in post-resuscitation therapy and to disentangle the relationship between PiCCO™-application, the patients' condition, and mortality by assessing it as an interaction effect. Methods In this longitudinal analysis of 63 comatose patients after successful cardiopulmonary resuscitation cooled to 32–34˚C, 30 patients received no PiCCO™ monitor application and 33 received PiCCO™. Primary and secondary outcomes were 30-day and one-year mortality. Kaplan-Meyer curves and corresponding Log-rank tests were used to assess differences in mortality among PiCCO™ vs non-PiCCO™ patients. Interaction effects (patient`s condition vs. PiCCO™ application vs. mortality) were assessed by means of Chi-square tests and logistic regression models. Results 30-day mortality was significantly, and one-year mortality was marginally higher among PiCCO™ patients. We found five interaction patterns between patients’ condition and being monitored with PiCCO™ with regard to mortality after 30 days, which distilled down to three interaction patterns by the end of the first year. More severe patient condition per se was not the cause of higher mortality rate in the PiCCO™ group. Moreover, patients in better health conditions (without ST-elevation myocardial infarction, without cardiogenic shock, without intra-aortic balloon pump device or without stroke in prior history) had worse outcomes in PiCCO™-guided therapy. Furthermore, catecholamine administration worsened both 30-day and one-year mortality among all patients. Conclusions Our analysis showed that there was a complex interaction relationship between PiCCO™-guided therapy, patients’ condition, and 30-day mortality for most conditions. Furthermore, in terms of one-year mortality, there was either no benefit whatsoever of PiCCO™ monitoring on survival or there was worse survival among patients who had no underlying conditions but received PiCCO™ (such as among patients who had no STEMI or had no stroke).