[Noradrenaline in the "high output-low resistance" state of patients with abdominal sepsis]

We investigated the impact of norepinephrine administration on hemodynamics, oxygen metabolism and renal function in patients in severe septic shock. PATIENTS AND METHODS. Twenty-six patients with extremely low resistance who were between 24 and 87 years of age were included in the study. In 7 patients, acute necrotizing pancreatitis and superinfection was diagnosed; 19 patients suffered from diffuse peritonitis. The entrance criteria for the study were: a mean arterial pressure (MAP) of below 60 torr or, in chronic hypertensive patients, a decrease in systolic pressure of more than 50 torr compared to previous values, despite volume optimization, and dopamine greater than 20 micrograms/kg per min and cumulative doses of dopamine/dobutamine greater than 30 micrograms/kg per min, respectively. Cases with tachycardia greater than 140/min were also included in the study even when the inotropic medication dose was lower. After registration of baseline values, dopamine was reduced to 2.5 micrograms/kg per min, and norepinephrine was administered starting at a dose rate of 0.05 micrograms/kg per min, until a MAP of greater than 60 torr could be maintained. RESULTS. Of the 26 patients investigated, 16 survived; 10 patients with persisting sepsis died due to multiple organ failure (mortality: 38.5%). During the study period, a norepinephrine dosage ranging between 0.1 and 2 micrograms/kg per min was necessary to stabilize the arterial pressure. The mean dose rate was 0.3 micrograms/kg per min. The mean arterial pressure and systemic vascular resistance index showed a statistically significant increase of 30 and 20%, respectively, just after 1 h and distinctly remained above the initial values in the further course. The cardiac index remained constant or increased slightly. After 24 h a statistically significant increase in stroke volume and a decrease in heart rate could be observed. Creatinine clearance increased significantly from the control value of 73 +/- 48 ml/min to 114 +/- 37 ml/min after 48 h under norepinephrine treatment. O2-delivery and O2-consumption did not change significantly, although they showed a slight tendency to increase. CONCLUSION. When patients are in a septic high output-low resistance condition, particular attention must be paid to maintaining sufficient mean arterial pressures. Our results suggest that this essential goal can be achieved by norepinephrine. The mean arterial pressure and glomerular filtration rate improved markedly, and there was no evidence of bad effects such as an increased afterload on critical parameters like cardiac index, O2-delivery and O2-consumption.