OBJECTIVE:

To study the effect of continuous infusion of vasopressin on the splanchnic circulation in patients with severe septic shock.

DESIGN:

Prospective clinical study.

SETTING:

ICU in a teaching hospital.

PATIENTS:

Eleven consecutive patients with documented septic shock who remained hypotensive despite norepinephrine infusion at a rate > or =0.2 microg/kg/min.

INTERVENTIONS:

Insertion of a gastric tonometry catheter, and continuous infusion of vasopressin 0.04 U/min during 4 h. Measurements and main results: Difference between gastric and arterial CO(2) partial pressure (P[g-a]CO(2) gap), mean arterial pressure, and cardiac index were recorded at baseline and after 15 min, 30 min, 60 min, 120 min, and 240 min.

RESULTS:

The median P(g-a)CO(2) gap increased from 5 mm Hg at baseline to 19 mm Hg after 4 h (p = 0.022). Mean arterial pressure increased from 61 +/- 13 mm Hg at baseline to 68 +/- 9 mm Hg after 4 h (p = 0.055). No significant changes in cardiac index were noted.

CONCLUSIONS:

In norepinephrine-dependent patients in septic shock, continuous infusion of low-dose vasopressin results in a significant increase of the P(g-a)CO(2) gap compatible with GI hypoperfusion.