BIS-guided deep sedation (Bispectral Sedation Index) as a temporary bridge to definitive treatment for refractory arrhythmogenic storm

Introduction Arrhythmogenic storm (AT) is the incessant occurrence of ventricular arrhythmias that destabilize the patient. In many cases, deep sedation is necessary to control the condition and treatment of the underlying cause of the AT. Objectively measuring the degree of sedation is not easy in unstable patients, which is why the BIS is a widely used device in anesthesia and can help assess the depth of sedation. Methods Retrospective and descriptive study of our series. Our hospital admits patients with AT refractory to conventional treatment to assess therapeutic options. Our objective is to determine whether the use of BIS can objectively achieve deep sedation and thus temporarily alleviate persistent ventricular arrhythmias for subsequent definitive treatment. Results Seventeen patients met the criteria for BP refractory to initial conventional treatment. 76% were men, with a mean age of 61.5 years. The predominant etiologies were ischemic cardiomyopathy (53%), followed by dilated cardiomyopathy (29.4%). The mean LVEF was 27% (range 10–50%), and the predominant arrhythmia type was monomorphic VT in 76.4%, followed by polymorphic VT (23.5%). Mechanical circulatory support was required in 76% of cases. All our patients were receiving IV antiarrhythmics, orotracheal intubation, and analgesia. Regarding deep sedation, it was established when BIS monitoring was <40. For this purpose, midazolam was used (100% of patients) or in combination with dexmedetomidine (50%) or propofol (20%). Achieving deep sedation (BIS <40) achieved control of ventricular arrhythmias in 12 (70%) cases, serving as a bridge to definitive treatment attempt through complete correction of triggers in 3 (18%), electrophysiological study and attempted ablation in 5 (29%) or heart transplantation in another 3 (18%) cases. It is also worth mentioning that in 4 cases deep sedation managed to mitigate arrhythmias; however, it was decided to limit the therapeutic effort because in 2 cases the ablation was not successful and they were not candidates for transplant and the other 2 due to other complications (sepsis, anoxic encephalopathy). Conclusions Deep sedation guided by BIS <40 helped in almost half of the cases (47%) to mitigate the continued appearance of ventricular arrhythmias, allowing time to attempt a definitive treatment. We believe that more powerful studies are necessary to corroborate our results.