Artikel
Reduced heart-rate variability in brain-dead patients as compared to comatose patients with and without brain stem lesions and healthy volunteers
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Autoren
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Imre Bondar
- Klinik für Neurochirurgie, Universität Magdeburg, Deutschland
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André Stegemann
- Klinik für Neurochirurgie, Universität Magdeburg, Deutschland
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Raimund Firsching
- Klinik für Neurochirurgie, Universität Magdeburg, Deutschland
| Veröffentlicht: | 16. September 2010 |
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Gliederung
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Objective: Heart rate variability (HRV) is defined as variation of the beat-to-beat R-R time interval between consecutive heart beats in the electrocardiogram (ECG). HRV reflects autonomic control of the cardio-vascular system, which may be impaired in patients with lesions of brain stem areas associated with autonomic control functions. The aim of the present study was to compare the HRV between patients exhibiting the clinical criteria of brain death and comatose patients without and with a brain stem lesion as verfied by MRI and with healthy volunteers
Methods: HRV was assessed in 11 healthy volunteers, in 20 comatose patients without a brain stem lesion in the MRI, in 24 comatose patients with a brain stem lesion verified by MRI and in 21 patients fulfilling the clinical criteria of brain death. The ECG was digitized by means of an analog-to-digital converter and sampled for a period of 30 minutes once a day (500 Hz sampling rate, 12 bit resolution). For each patient, consecutive normal R-R time intervals [s] were determined from these time-series and used to calculate the standard deviation of beat-to-beat intervals (SDNN) and the root mean square of successive differences (RMSSD), two common HRV parameters. Analysis of variance (ANOVA) was used to compare group differences for statistical significance
Results: Patients exhibiting the clinical criteria of brain death showed a marked and statistically significant (p<0.05) reduction of both HRV-paramerters (SDNN=0.0056±0.0054, RMSSD=0.003) as compared to comatose patients with (SDNN=0.019±0.018, RMSSD=0.018) and without a brain stem lesion (SDNN=0.031±0.027, RMSSD=0.032) and healthy volunteers (SDNN=0.080±0.028, RMSSD=0.059).
Conclusions: Our results show that HRV is markedly reduced in patients exhibiting the clinical criteria of brain death as compared to comatose patients with and without brain stem lesions. The assessment of HRV might provide a novel noninvasive approach to confirmation of the cessation of brain stem function.
