Cardiac variability in critically ill adults: influence of sepsis.

OBJECTIVE: To evaluate, in critically ill adults, factors associated with impaired sympathovagal balance. DESIGN: One-month inception cohort study. SETTING: Twenty-six-bed medical intensive care unit of a teaching hospital. PATIENTS: Critically ill adults with an expected duration of intensive care unit stay of > or =48 hrs were enrolled. Patients with permanent arrhythmia or cardiac pacing were not included. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: Sympathovagal balance was assessed on the day after intensive care unit admission by the low-frequency/high-frequency ratio obtained from spectral components of heart rate signal: overall variability, low frequency, and high frequency. RESULTS: Forty-one patients, 13 with sepsis and 28 without sepsis, were assessed. Predictors of low-frequency/high-frequency ratio with the automatic interaction detection method were sepsis and age. Binary logit analysis adjusted for age showed that sepsis remained a strong and independent factor of a low-frequency/high-frequency ratio of <1.50, with an odds ratio of 3.63 (95% confidence interval, 1.47-9.01, p =.005). Use of mechanical ventilation, catecholamines, or sedation did not add any information. The use of the low-frequency/high-frequency ratio in diagnosing sepsis may be supported by a likelihood ratio for low frequency/high frequency <1 at 6.47. CONCLUSIONS: This work suggests that impaired cardiac variability and notably sympathovagal balance (i.e., a low-frequency/high-frequency ratio <1.0) may be a diagnostic test for sepsis.

Correlations between kinematic and rating scale measures of tardive dyskinesia in a developmentally disabled population.

This paper reports a study that examines the relations between Dyskinesia Identification System: Condensed User Scale (DISCUS) scores and a battery of postural and movement kinematic measures in a group of adults diagnosed as being developmentally disabled and screened as having tardive dyskinesia. The results showed that finger tremor measures correlated with the tongue tremor and pill rolling items of DISCUS, whereas the postural stability scores correlated with the toe movement item of DISCUS and the total DISCUS score. There was also a high stability in subject kinematic performance from trial to trial over the postural and movement tests. The pattern of correlations between the DISCUS items and movement kinematic measures is consistent with the proposition that tremor is a centrally rather than peripherally driven phenomenon, although many factors contribute to emergent tremors. These findings provide construct and content validity for the DISCUS as a screening device for tardive dyskinesia and suggest that certain posture and movement kinematic measures could be sensitive measuring methods for tardive dyskinesia in developmentally disabled populations.