Norepinephrine in low to moderate doses may not increase luminal concentrations of l‐lactate in the gut in patients with septic shock*

Aim: To investigate the effect of different doses of norepinephrine (noradrenaline) on luminal concentrations of l ‐lactate in the rectum and stomach in patients with fluid‐resuscitated septic shock. Methods: This was a paired cross‐over study in which the dose of norepinephrine was titrated to mean arterial blood pressures (MAPs) of 65 and 85 mmHg in random sequence. It was performed in a mixed intensive care unit at a university hospital. Eight patients with fluid‐resuscitated septic shock requiring norepinephrine (>0.1 μg/kg/min) were included. Patients were treated with norepinephrine to a MAP of either 65 or 85 mmHg for 2 h. After a ‘washout’ period of 2 h, the dose of norepinephrine was titrated to the other endpoint of MAP for another 2 h. The concentrations of l ‐lactate in the rectal and gastric lumen were estimated by 1‐h equilibrium dialysis during the second hour of the treatment periods. Results: MAP and central venous oxygen saturation were increased by increasing the dose of norepinephrine [median (range) (μg/kg/min): 0.07 (0.00–0.60) and 0.18 (0.11–1.00) at MAPs of 65 and 85 mmHg, respectively], whereas the metabolic markers were unaffected [luminal concentrations (mmol/l) of l ‐lactate in the rectum of 1.9 (0.8–6.4) and 1.8 (0.9–5.7) ( P = 0.94) and in the stomach of 1.1 (0.1–10.0) and 1.3 (0.3–9.7) ( P = 0.88) at MAPs of 65 and 85 mmHg, respectively]. Conclusion: In this small study, luminal concentrations of l ‐lactate in the rectum and stomach were unaffected by norepinephrine at low to moderate doses. These data suggest that norepinephrine may not increase luminal concentrations of l ‐lactate in the gut in patients with fluid‐resuscitated septic shock.