Investigation of the effect of vital parameters on cerebral oxygenation in patients undergoing ventricular tachycardia ablation

Ventricular tachycardia is a tachyarrhythmia that is associated with wide QRS complexes on ECG, originates from the ventricular myocardium and has consequences such as syncope and sudden cardiac death if left untreated. Therefore, VT ablation therapy is indicated, especially in patients with persistent VT attacks and/or a history of multiple shocks despite anti-arrhythmic drug therapy. NIRS monitoring during the procedure is clinically important, especially since the optimal MAP required to maintain end-organ perfusion during VT is unknown. In our prospective observational study; correlation of right and left side measurements of NIRS values with measurements in VT ablation process and clinical characteristics of patients was investigated. After the approval of the ethics committee, the demographic data, intraoperative vital values, intraoperative NIRS and BIS values of the patients who would undergo VT ablation under general anesthesia between 30 June and 31 December 2021 were recorded. The study included 37 patients who underwent ablation for VT with pulse; due to the fact that different values were obtained from each of 37 patients during ablation, 2 separate data sets were obtained from each patient, and a total of 74 VT processes were examined. According to the data obtained from the VT processes, it was determined that the decreases in the right and left NIRS measurements (˃10%) showed a significant correlation with MAP (p= 0.007 and 0.006, respectively) and ETCO2 (p= <0.001 and <0.001, respectively) values in the VT process. However, it was observed that right and left NIRS decreases were significantly different in patients with PAP ˃ 30mmHg compared to patients with PAP ≤30mmHg (p=0.002 and 0.004, respectively). A similar relationship was not found with age, EF, and gender, or with BIS in the VT process. However, when initial left NIRS, right NIRS and MAP values were examined, it was shown that the median values of women were lower than men, and the result was statistically significant (p<0.001, p=0.001, p=0.011, respectively). In our study, both VT data and VF data were evaluated together with the patients' baseline values, and it was found that ETCO2 and NIRS values were positively correlated with or without pulsatile blood flow. In cases where routine NIRS is not used and ETCO2 monitoring is performed under general anesthesia, when there is a sudden ETCO2 and MAP decrease, it should be considered that cerebral oxygenation may be insufficient because these parameters are correlated with NIRS. Due to the rapid response of the NIRS probe to hemodynamic changes and its instant correlation with MAP and ETCO2; in addition to its use in cases where general anesthesia is applied, the use of active NIRS in pulseless VT/VF cases can be considered as it may be effective in determining the quality of compression and in monitoring the return of spontaneous circulation (ROSC).