title: Plasma NE concentrations do not accurately reflect sympathetic nervous system activity in human sepsis.
abstract: Plasma norepinephrine concentrations ([NE]) when raised in patients with sepsis are thought to indicate increased activity of the sympathetic nervous system (SNS). However, increased SNS activity may occur without a concomitant rise in plasma [NE]. Measurement of NE kinetics (clearance and spillover) is a more accurate and direct assessment of SNS activity. In the present study plasma [NE] and NE kinetics were measured in six patients with intra-abdominal sepsis (septic) using tritiated NE infused to achieve a plateau plasma concentration. The measurements were repeated in the same patients after they had recovered (nonseptic). NE clearance and spillover were both significantly higher (P < 0.05) in the septic compared with the nonseptic state. However, there was no statistically significant difference in plasma [NE] between the two conditions. Plasma [NE] indicates no alteration in SNS activity during the septic state, whereas NE kinetics indicate increased activity of the SNS during sepsis. The results suggest that plasma [NE] is a poor indicator of SNS activity during septic illness.
authors.affiliation: Department of Surgery, University of Manchester, Hope Hospital, Salford, United Kingdom.
authors.forename: D J
authors.initials: DJ
authors.lastname: Leinhardt
authors.forename: J
authors.initials: J
authors.lastname: Arnold
authors.forename: K A
authors.initials: KA
authors.lastname: Shipley
authors.forename: M M
authors.initials: MM
authors.lastname: Mughal
authors.forename: R A
authors.initials: RA
authors.lastname: Little
authors.forename: M H
authors.initials: MH
authors.lastname: Irving
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007239:Infections / Q000097:blood* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood*; D009994:Osmolar Concentration; D012016:Reference Values; D013564:Sympathetic Nervous System / Q000503:physiopathology*
chemical_list: D009638:Norepinephrine