Effect of Hydrocortison on Post-ischemic Flow-mediated Dilation and on Thenar Oxygen Saturation in Human Septic Shock.

Effect of Intravenous Hydrocortison on Post-ischemic Brachial Artery Dilation and on Thenar Oxygen Saturation in Adult Septic Shock. A Human Placebo-controlled Randomized Study.

The main objectives of the study are 1)to examine the immediate (2 hours) and delayed (8 hours) effects of intravenous hydrocortison on macro and microvascular post-ischemic vasoreactivity, in septic shock adult patients; 2) to examine possible correlations between post-ischemic flow-mediated dilation (FMD) of the brachial artery (assessed by ultrasound imaging) and post-ischemic recovery slope of the thenar oxygen saturation (StO2) (assessed by near-infrared spectroscopy).

Two primary end points, considered as reflecting vasoreactivity will be assessed :

1. Flow-mediated dilation (FMD) of the brachial artery, measured by ultrasound imaging, expressed in mm or in percentage, will be calculated from artery diameters measured before and after a vascular occlusion test (cuff around arm or forearm).
2. recovery slope of thenar oxygen saturation (StO2), assessed by near infrared spectroscopy (NIRS), expressed in %/second, will be recorded after the vascular occlusion test.

The two primary end points (FMD and recovery slope of StO2)will be assessed at the following timepoints :

• baseline (before first injection of placebo or hydrocortison)
• 2 hours after first injection of placebo or hydrocortison
• 2 hours after second injection of placebo or hydrocortison (i.e. 8 hours after first injection)
• 4 to 6 hours after third injection
• 4 to 6 hours after fourth injection (optional)

Inclusion Criteria:

• age over 18 yrs
• consent obtained
• septic shock (according to international definition)
• patient sedated and submitted to invasive mechanical ventilation
• no need for surgery expected within 24 hours after enrollment
• patient has received at least one dose of large spectrum antibiotics
• superior vena cava catheter in place
• patient carrying a thermodilution device for cardiac output measurement
• stable mean arterial pressure within 65-5 mmHg limits for at least 2 hours;

Exclusion Criteria:

• pregnancy
• age below 18 years
• patient treated with iv continuous epinephrine
• chronic occlusive arteriopathy of the upper limbs
• regular or recent treatment with glibenclamide or glipizide
• regular or recent treatment with steroids
• known surrenal insufficiency