Elevated serum bleomycin-detectable iron concentrations in patients with sepsis syndrome

Objective To determine serum bleomycin-detectable free iron in patients with septic shock and to relate these findings to both outcome and a marker of free radical damage.Design A prospective observational study.Setting A nine-bed intensive care unit in a university teaching hospital.Patients Sixteen consecutive patients with septic shock, defined as: (1) Clinical evidence of acute infection; (2) hypo- or hyperthermia (<35.6° or >38.3°C); (3) tachypnoea (>20 breaths/min or ventilated); (4) tachycardia (>90 beats min); (5) shock (systolic pressure <90 mmHg) or on inotropes. Fourteen patients also had secondary organ dysfunction.Measurements and results Bleomycin-detectable iron concentrations were elevated in all patients (37.2±11.0 mol/l vs 5.1±3.3 mol/l in healthy subjects,P<0.0001), but there was no difference between patients who died and those who survived (39.2±9.3 and 36.2±12.3 mol/l, respectively). Thiobarbituric acid reactive substances 9an index of lipid peroxidation) were higher in those who died (3.33±2.29 mol/l) than in the surviving patients (0.99±0.14 mol/l,P<0.01) or healthy subjects (0.92±0.39 mol/l,P<0.01). Free iron did not correlate with thiobarbituric acid-reactive substances. However, a significant correlation was found between lipid peroxidation and clinical severity (APACHE II) score (r=0.54,P<0.05).Conclusions The present study provides evidence of lipid peroxidation in patients who die with septic shock. The data suggest that ironcatalysed hydroxyl radical generation does not form an important contribution to this lipid peroxidation in patients with sepsis.