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

Evaluation of changes in the peak latencies of sensory evoked potentials 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.

Prospective cohort study.

Intensive care units of the university hospital, Vienna.

Patients (n = 103) treated on an intensive care unit because of multiple organ failure with additional metabolic encephalopathy. Multiple organ failure was induced by sepsis (group A; n = 56), surgery (group B; n = 29), or both (group C; n = 18).

None.

Metabolic encephalopathy was determined by measuring median nerve-stimulated short-latency and long-latency sensory evoked potentials. No differences in the peak latencies of the sensory evoked potentials were detected among the groups. Septic patients had a N70 peak latency of 131+/-21 msecs, nonseptic postsurgical patients of 132+/-17 msecs, and septic postsurgical patients of 134+/-17 msecs. The cervicomedullary 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 were significantly prolonged compared with peak latencies of healthy controls. The severity of illness assessed by the Acute Physiology and Chronic Health Evaluation III score was not different between the three groups. An increase of the delay of N70 peak latencies was significantly correlated with the severity of illness (r2 = .15; p < .00005).

There was no difference in sensory evoked potential measurements detectable among septic patients with multiple organ failure, nonseptic postsurgical patients with multiple organ failure, and septic postsurgical patients with multiple organ failure. The N70 peak latency was significantly correlated with the severity of illness but not with the presence or absence of sepsis. In postsurgical patients with multiple organ failure and superimposed sepsis, the N70 peak latencies were not further prolonged compared with postsurgical patients without sepsis.