Influence of antibiotic therapy with hemodynamic optimization on 30-day mortality among septic shock patients cared for in the prehospital setting

Background: In order to reduce septic shock mortality, international guidelines recommend early treatment implementation, antibiotic therapy (ABT) and hemodynamic optimisation, within 1-h. This retrospective multicentric study aims to investigate the relationship between prehospital ABT delivered within 1st hour and mean blood pressure (MAP) >= 65 mmHg at the end of the prehospital stage, and 30-day mortality among patients with septic shock.Methods: From May 2016 to December 2021, patients with septic shock requiring pre-hospital Mobile Intensive Care Unit intervention (MICU) were retrospectively analysed. To assess the relationship between 30-day mortality and prehospital ABT delivered within 1st hour and/or MAP >= 65 mmHg at the end of the prehospital stage, Inverse Probability Treatment Weighting (IPTW) propensity score method was performed.Results: Among the 530 patients included, 341 were male gender (64%) with a mean age of 69 +/- 15 years. One-hundred and thirty-two patients (25%) patients received prehospital ABT, among which 98 patients (74%) were treated with 3rd generation cephalosporin. Suspected pulmonary, urinary and digestive infections were the cause of sepsis in respectively 43%, 25% and 17%. The 30-day overall mortality was 31%. A significant association was observed between 30-day mortality rate and (i) ABT administration within the first hour: RRa = 0.14 [0.04-0.55], (ii) ABT administration within the first hour associated with a MAP >= 65 mmHg: RRa = 0.08 [0.02-0.37] and (iii) ABT administration within the first hour in the prehospital setting associated with a MAP < 65 mmHg at the end of the prehospital stage: RRa = 0.75 [0.45-0.85]. Patients who received prehospital ABT after the first hour have also a 30-day mortality rate decrease: RRa = 0.87 [0.57-0.99], whereas patients who did not received ABT had an increased 30-day mortality rate: RRa = 2.36 [1.89-2.95].Conclusion: In this study, we showed that pre-hospital ABT within the first hour and MAP >= 65 mmHg at the end of prehospital stage are both associated with 30-day mortality decrease among patients suffering from septic shock cared for by a MICU. Further prospective studies are needed to confirm these preliminary results.