Metabolic encephalopathy in critically ill patients suffering from septic or nonseptic multiple organ failure

Objective: Evaluation of changes in the peak latencies of sensory evoked po tentials in different patient groups, to evaluate differences in metabolic encephalopathy of critically ill patients with multiple organ failure as a result of septic or nonseptic conditions. Design: Prospective cohort study. Setting: Intensive care units of the university hospital, Vienna. Patients. Patients (n = 103) treated on an intensive care unit because of m ultiple organ failure with additional metabolic encephalopathy. Multiple or gan failure was induced by sepsis (group A; n = 56), surgery (group B; n = 29), or both (group C; n = 18). Interventions: None. Measurements and Main Results: Metabolic encephalopathy was determined by m easuring median nerve-stimulated short-latency and long-latency sensory evo ked potentials. No differences in the peak latencies of the sensory evoked potentials were detected among the groups. Septic patients had a N70 peak l atency of 131 +/- 21 msecs, nonseptic postsurgical patients of 132 +/- 17 m secs, and septic postsurgical patients of 134 +/- 17 msecs. The cervicomedu llary N13 to cortical N20 conduction times were 6.4 +/- 1 msec, 6.4 +/- 1.4 msecs, and 6.8 +/- 1.2 msecs, respectively. All measured peak latencies we re significantly prolonged compared with peak latencies of healthy controls . The severity of illness assessed by the Acute Physiology and Chronic Heal th Evaluation III score was not different between the three groups. An incr ease of the delay of N70 peak latencies was significantly correlated with t he severity of illness (r(2) = .15; p < .00005). Conclusion: There was no difference in sensory evoked potential measurement s detectable among septic patients with multiple organ failure, nonseptic p ostsurgical patients with multiple organ failure, and septic postsurgical p atients with multiple organ failure. The N70 peak latency was significantly correlated with the severity of illness but not with the presence or absen ce of sepsis. In postsurgical patients with multiple organ failure and supe rimposed sepsis, the N70 peak latencies were not further prolonged compared with postsurgical patients without sepsis.