Indicators of dysautonomia in severe Guillain-Barre syndrome

This study sought to establish quantitative criteria for dysautonomia in ar tificially ventilated patients with Guillain-Barre syndrome (GBS). Such cri teria would help to identify patients at risk for cardiovascular complicati ons. This retrospective controlled clinical study compared hourly cardiovas cular monitoring data from 36 successive, artificially ventilated GBS patie nts with that from 11 artificially ventilated control patients with myasthe nia. Tolerance limits for daily means, extremes, and variations in heart ra te (HR) and blood pressure (BP) were estimated from the most abnormal subgr oups of the treatment days of our control patients. These exceeded previous ly suggested arbitrary cutoff values for dysautonomia. The range in systoli c 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 patient s with mean systolic BP above 165 mmHg also had persistent tachycardia (mea n HR > 125 bpm), or were treated with beta-blockers. This pattern of sympat hetic hyperactivity was combined with probable vagal hyperactivity (bradyca rdia < 48 bpm) in 6 patients. Hypotension (minimal systolic BP < 85 mmHg) a nd unprovoked bradycardia indicated sympathetic hypoactivity in 3 patients. Except in one patient who suffered from asystole on his first day on the I CY, all episodes of bradycardia were preceded by increased daily systolic B P variation (> 85 mmHg), which thus proved to be a sensitive and prognostic ally valuable indicator of dysautonomia in GBS.