Vitamin B1 (Thiamine) is a water-soluble vitamin that plays an important role in various biological processes. The active form is thiamine pyrophosphate, an essential cofactor in enzyme systems involved in carbohydrate metabolism and energy production. Recently, the role of thiamine in critically ill patients has gained prominence and septic shock has deserved special attention (1,2). It is important to emphasize that in these situations the clinical syndromes have low sensitivity and specificity for clinical diagnosis, which means that a high level of suspicion must be exercised in these situations. Donnino et al (3) analyzed 88 patients with septic shock in a prospective, randomized, double-blind study. The study showed that the administration of thiamine at a dose of 200 mg every 12 hours for 7 days had a significant impact on mortality only in patients who had reduced serum levels of thiamine. Woolum et al (4 ) retrospectively analyzed the impact of a single dose of Thiamine administered in the 24 hours that preceded the diagnosis of septic shock and compared with patients who did not receive the vitamin and identified improvement in lactate clearance and reduction in 28-day mortality in the thiamine group. Petsakul et al (5) evaluated the effect of thiamine administration in patients with septic shock and need for vasopressors and showed a significant reduction in the vasopressor dose in addition to improvement in lactate clearance. A recent meta-analysis including 5 studies and 645 patients with septic shock analyzed the impact of thiamine use on mortality. The study included 3 prospective randomized studies and 2 retrospective observational studies. The result showed a borderline beneficial effect on mortality. Regarding to HAT (Hydrocortisone, ascorbic acid and thiamine) therapy after the initial study by Marik et al. (7 ) at least 3 prospective randomized studies failed to repeat the good results of the initial study (8,9,10).

The sepsis management protocol at the São Domingos hospital underwent important changes from December 2021 to October 2022. In December, changes were incorporated in the protocol based on the new version of the Surviving Sepsis Campaign 2021 that had been launched the previous month ( 11). In April 2022 the SOSD (salvage, optimization, stabilization and de-resuscitation) systematics (12) was incoporated in the management of septic shock and in October 2022 thiamine use was implemented. Thiamine was incorporated into the protocol, although there are still no robust studies to indicate its use because, despite the implementation of previous measures with exceptional results in sepsis, between January and September 2022, mortality from sepsis was 1.69%, in the septic shock we had evolved little or nothing with mortality in the same period of 70%. In October, thiamine was started in isolated cases and as of November 2022, the investigators started using thiamine systematically and in all cases of septic shock at a dose of 200 mg EV every 12 hours for 7 days. In this controlled before-and-after study, the investigators compared outcomes of patients treated for septic shock between November 2022 and March 2023 with patients diagnosed with septic shock treated between May and September 2022.