Hypotension during endotoxemia in aged humans

Background and objective The aim of this study was to determine possible ag e-associated differences in human blood pressure regulation during an immun ological challenge in healthy subjects. Methods Eight healthy young volunteers (median age 24 yr) and nine healthy elderly volunteers (median age 66 yr) received an intravenous bolus injecti on of Eschericia coli endotoxin (2 ng kg(-1)). Blood pressure, heart rate a nd core temperature were monitored during the first 7 h. Plasma catecholami ne concentrations were measured at hourly intervals. Results The elderly showed a significantly more pronounced decrease in mean arterial pressure 4-7 h after endotoxin administration compared with the y oung controls (ANOVA; age x time; P < 0.0005). This mainly reflected a decr ease in the systolic blood pressure in the elderly. The heart rate of both groups increased without difference between groups. Increased plasma epinep hrine concentrations were found 2-3 h after endotoxin administration in bot h groups. Five hours after the endotoxin challenge, the epinephrine concent ration had returned to control values in the elderly group only, in spite o f decreased blood pressure. Conclusion In conclusion, healthy elderly subjects fail to maintain a const ant mean arterial pressure in response to the immunological challenge of en dotoxemia.