Dexmedetomidine to Reduce Vasopressor Resistance in Refractory Septic Shock: α2 Agonist Dexmedetomidine for...

Increasing evidence has suggested the benefits of dexmedetomidine in patients with sepsis. Dexmedetomidine may increase vasopressor sensitivity, which may be of interest in the setting of refractory septic shock. The α2 Agonist Dexmedetomidine for REfractory Septic Shock (ADRESS) pilot study aimed to evaluate the effect of dexmedetomidine on the vasopressor response in patients with refractory septic shock.

This study was a multicenter, randomized, placebo-controlled, double-blind pilot trial.

The study was conducted in 5 ICUs in France.

Inclusion criteria were septic shock (Sepsis-3 definition) and norepinephrine requirement greater than or equal to 0.25 µg/kg/min (0.5 µg/kg/min of norepinephrine tartrate) with persistent circulatory failure (defined by lactate > 2 mmol/L, oliguria, or skin mottling) and invasive mechanical ventilation.

The arterial pressure response to phenylephrine was measured before starting the treatment (0 hr), at 6 hours (primary outcome), and 12 hours. In the treatment arm, dexmedetomidine was given at a fixed dose of 1 µg/kg/hr.

Inclusions were stopped early because of higher mortality in the dexmedetomidine arm. Thirty-two patients of the 36 planned were included. Response to phenylephrine at 6 hours was lower in the dexmedetomidine group than in the placebo group (1.26 ± 0.23 vs. 1.45 ± 0.26; p = 0.048), although this difference was also observed at baseline ( p = 0.029). There were no significant differences between the groups in terms of cumulative norepinephrine dose, lactatemia, Sequential Organ Failure Assessment score, fluid balance, ventilation-free days, or occurrence of bradycardia. Mortality on day 3 was higher in the dexmedetomidine group than in the placebo group, with a difference that diminished and was no longer significant on 30 and 90 days.

Patients in the dexmedetomidine arm had a significantly lower response to phenylephrine at all study times including baseline, which might have contributed to higher early mortality in the dexmedetomidine arm and preclude to conclude on dexmedetomidine efficacy in refractory septic shock. However, heart rate was not decreased in the dexmedetomidine arm.