The cardiac R-R variation and sympathetic skin response in the intensive care unit

Background and Purpose: The central and peripheral nervous systems are often affected in intensive care unit (ICU) patients, especially those with prolonged assisted ventilation and sepsis or systemic inflammatory response syndrome (SIRS). The autonomic nervous system, however, has been under-investigated in such patients. We evaluated autonomic nervous system (ANS) function in 29 ICU patients with various neurological disorders. Methods: Testing involved cardiac R-R variation (CRRV) as an index of parasympathetic function and the sympathetic skin response (SSR) for sympathetic assessment. Results: Only those 8 patients with sepsis-related neuropathy or encephalopathy had abnormal CRRV, while the SSR was absent in all but 2 patients. Conclusions: Our preliminary study revealed a high incidence of autonomic dysfunction in ICU patients with various neurological disorders.