Indicators of dysautonomia in severe Guillain-Barré syndrome

This study sought to establish quantitative criteria for dysautonomia in artificially ventilated patients with Guillain-Barré syndrome (GBS). Such criteria would help to identify patients at risk for cardiovascular complications. This retrospective controlled clinical study compared hourly cardiovascular monitoring data from 36 successive, artificially ventilated GBS patients with that from 11 artificially ventilated control patients with myasthenia. Tolerance limits for daily means, extremes, and variations in heart rate (HR) and blood pressure (BP) were estimated from the most abnormal subgroups of the treatment days of our control patients. These exceeded previously suggested arbitrary cutoff values for dysautonomia. The range in systolic BP was increased in 27 GBS patients, despite an upper limit of normal (85 mmHg) that was double the value suggested in previous work. All 16 patients with mean systolic BP above 165 mmHg also had persistent tachycardia (mean HR > 125 bpm), or were treated with beta-blockers. This pattern of sympathetic hyperactivity was combined with probable vagal hyperactivity (bradycardia < 48 bpm) in 6 patients. Hypotension (minimal systolic BP < 85 mmHg) and unprovoked bradycardia indicated sympathetic hypoactivity in 3 patients. Except in one patient who suffered from asystole on his first day on the ICU, all episodes of bradycardia were preceded by increased daily systolic BP variation (> 85 mmHg), which thus proved to be a sensitive and prognostically valuable indicator of dysautonomia in GBS.