N-acetyl-L-cysteine depresses cardiac performance in patients with septic shock.
OBJECTIVE
To investigate the effects of adjunctive therapy with parenteral N-acetyl-L-cysteine in patients with newly diagnosed septic shock.


METHODS
Prospective, randomized, double-blind, placebo-controlled study.


METHODS
Multidisciplinary intensive care unit at a university teaching hospital.


METHODS
Twenty patients (N-acetyl-L-cysteine group [n = 10], placebo group [n = 10]), 15 male and five female, of mean age 64 +/- 15 (SD) yrs and Acute Physiology and Chronic health Evaluation (APACHE) II score 33 +/- 6, with septic shock within 24 hrs of diagnosis.


METHODS
After a 2-hr stabilization period (time-zero minus 2 hrs to time-zero), patients received either N-acetyl-L-cysteine in 5% dextrose (150 mg/kg in 100 mL over 15 mins, followed by 50 mg/kg in 250 mL over 4 hrs, and then 100 mg/kg/24 hrs in 500 mL for 44 hrs; N-acetyl-L-cysteine group) or the equivalent volume of 5% dextrose (placebo group).


RESULTS
Hemodynamic and oxygen transport indices were measured at time-zero minus 2 hrs and time-zero, and at multiple time points thereafter until completion of the trial infusion (time-zero plus 48 hrs). A daily Organ Failure Score was recorded for 14 days. Treatment group demographics and hemodynamic variables did not differ significantly between the two groups at time-zero. Mean (SD), pooled mean arterial pressure (MAP), and cardiac index were 75 +/- 15 mm Hg and 3.9 +/- 1.2 L/min/m2, respectively. Over the next 48 hrs, in the N-acetyl-L-cysteine group, there was a progressive decrease, relative to both time-zero and the placebo group, in MAP, cardiac index, and left ventricular stroke work index (p < .01, repeated-measures analysis of variance). Percentage reductions in these values relative to the placebo group at 48 hrs were 23%, 18%, and 43%, respectively Oxygen transport indices, arterial blood gas analyses, Pao2/Fio2 ratio, and shunt did not differ over time between the groups. There was no difference in either daily Organ Failure Score over time (p > .01, repeated-measures analysis of variance) or hospital mortality rate (90% N-acetyl-L-cysteine group, 50% placebo group) (p > .1, logistic regression) between the two groups.


CONCLUSIONS
Adjunctive therapy with N-acetyl-L-cysteine in newly diagnosed septic shock was associated with a depression in cardiovascular performance, as indicated by progressive reductions in cardiac index, left ventricular stroke work index, and MAP.
Peake
S L
SL
Intensive Care Unit, Queen Elizabeth Hospital, Woodville, Australia.
Moran
J L
JL
Leppard
P I
PI
D018806:APACHE; D000111:Acetylcysteine / Q000494:pharmacology / Q000627:therapeutic use*; D000368:Aged; D002395:Catecholamines / Q000097:blood; D004311:Double-Blind Method; D005260:Female; D006321:Heart / Q000187:drug effects*; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012772:Shock, Septic / Q000188:drug therapy*
D002395:Catecholamines; D000111:Acetylcysteine