Abstract
OBJECTIVES—To evaluate spontaneous blood pressure and heart rate variability and spontaneous baroreflex sensitivity before and after brain death. METHODS—Spontaneous variability of arterial blood pressure and heart rate—estimated by power spectra of systolic (SBP) and diastolic blood pressure (DBP) and pulse interval (PI)—and spontaneous baroreflex sensitivity (BRS)—estimated by the alpha index and the sequence technique—were evaluated in 11 patients twice: shortly before and 1 hour after the onset of brain death. RESULTS—Significant spectral changes occurred after brain death: a general power reduction in PI spectra; a shift of SBP, DBP and PI powers toward the lower frequencies, resulting in a greater slope of the "1/f" spectral trends; and a marked reduction of SBP and DBP powers (-93%) and of SBP-PI coherence (−63%) at 0.1Hz. The estimated average BRS was relatively high before brain death (around 11 ms/mm Hg), and fell close to 0 or even was not detectable at all after brain death. CONCLUSIONS—Parameters describing spontaneous blood pressure and heart rate variability and indexes reflecting the baroreflex function, which were relatively normal up to a few hours before brain death, underwent marked changes with the onset of brain death. All the changes found are likely to reflect the cessation of activity of the cardiovascular brain stem centres. These findings indicate that techniques of blood pressure and heart rate spectral analysis and of dynamic assessment of baroreflex sensitivity may be useful to complement the diagnosis of brain stem death.
Full Text
The Full Text of this article is available as a PDF (261.4 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bernardi L., Keller F., Sanders M., Reddy P. S., Griffith B., Meno F., Pinsky M. R. Respiratory sinus arrhythmia in the denervated human heart. J Appl Physiol (1985) 1989 Oct;67(4):1447–1455. doi: 10.1152/jappl.1989.67.4.1447. [DOI] [PubMed] [Google Scholar]
- Bertinieri G., Di Rienzo M., Cavallazzi A., Ferrari A. U., Pedotti A., Mancia G. Evaluation of baroreceptor reflex by blood pressure monitoring in unanesthetized cats. Am J Physiol. 1988 Feb;254(2 Pt 2):H377–H383. doi: 10.1152/ajpheart.1988.254.2.H377. [DOI] [PubMed] [Google Scholar]
- Bigger J. T., Jr, Steinman R. C., Rolnitzky L. M., Fleiss J. L., Albrecht P., Cohen R. J. Power law behavior of RR-interval variability in healthy middle-aged persons, patients with recent acute myocardial infarction, and patients with heart transplants. Circulation. 1996 Jun 15;93(12):2142–2151. doi: 10.1161/01.cir.93.12.2142. [DOI] [PubMed] [Google Scholar]
- Castiglioni P., Parati G., Omboni S., Mancia G., Imholz B. P., Wesseling K. H., Di Rienzo M. Broad-band spectral analysis of 24 h continuous finger blood pressure: comparison with intra-arterial recordings. Clin Sci (Lond) 1999 Aug;97(2):129–139. [PubMed] [Google Scholar]
- Challis R. E., Kitney R. I. Biomedical signal processing (in four parts). Part 3. The power spectrum and coherence function. Med Biol Eng Comput. 1991 May;29(3):225–241. doi: 10.1007/BF02446704. [DOI] [PubMed] [Google Scholar]
- Conci F., Procaccio F., Arosio M., Boselli L. Viscero-somatic and viscero-visceral reflexes in brain death. J Neurol Neurosurg Psychiatry. 1986 Jun;49(6):695–698. doi: 10.1136/jnnp.49.6.695. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Crenna P., Conci F., Boselli L. Changes in spinal reflex excitability in brain-dead humans. Electroencephalogr Clin Neurophysiol. 1989 Sep;73(3):206–214. doi: 10.1016/0013-4694(89)90121-1. [DOI] [PubMed] [Google Scholar]
- Di Rienzo M., Castiglioni P., Parati G., Mancia G., Pedotti A. Effects of sino-aortic denervation on spectral characteristics of blood pressure and pulse interval variability: a wide-band approach. Med Biol Eng Comput. 1996 Mar;34(2):133–141. doi: 10.1007/BF02520018. [DOI] [PubMed] [Google Scholar]
- Goldstein B., DeKing D., DeLong D. J., Kempski M. H., Cox C., Kelly M. M., Nichols D. D., Woolf P. D. Autonomic cardiovascular state after severe brain injury and brain death in children. Crit Care Med. 1993 Feb;21(2):228–233. doi: 10.1097/00003246-199302000-00014. [DOI] [PubMed] [Google Scholar]
- Goldstein B., Kempski M. H., DeKing D., Cox C., DeLong D. J., Kelly M. M., Woolf P. D. Autonomic control of heart rate after brain injury in children. Crit Care Med. 1996 Feb;24(2):234–240. doi: 10.1097/00003246-199602000-00009. [DOI] [PubMed] [Google Scholar]
- Goldstein B., Toweill D., Lai S., Sonnenthal K., Kimberly B. Uncoupling of the autonomic and cardiovascular systems in acute brain injury. Am J Physiol. 1998 Oct;275(4 Pt 2):R1287–R1292. doi: 10.1152/ajpregu.1998.275.4.R1287. [DOI] [PubMed] [Google Scholar]
- Ivan L. P. Spinal reflexes in cerebral death. Neurology. 1973 Jun;23(6):650–652. doi: 10.1212/wnl.23.6.650. [DOI] [PubMed] [Google Scholar]
- Johansson B., Bohr D. F. Rhythmic activity in smooth muscle from small subcutaneous arteries. Am J Physiol. 1966 Apr;210(4):801–806. doi: 10.1152/ajplegacy.1966.210.4.801. [DOI] [PubMed] [Google Scholar]
- Kero P., Antila K., Ylitalo V., Välimäki I. Decreased heart rate variation in decerebration syndrome: quantitative clinical criterion of brain death? Pediatrics. 1978 Sep;62(3):307–311. [PubMed] [Google Scholar]
- Kita Y., Ishise J., Yoshita Y., Aizawa Y., Yoshio H., Minagawa F., Shimizu M., Takeda R. Power spectral analysis of heart rate and arterial blood pressure oscillation in brain-dead patients. J Auton Nerv Syst. 1993 Aug-Sep;44(2-3):101–107. doi: 10.1016/0165-1838(93)90022-m. [DOI] [PubMed] [Google Scholar]
- Knüttgen D., zur Nieden K., Müller-Gorges M. R., Jahn M., Doehn M. Computer aided analysis of heart rate variability in brain death. Int J Clin Monit Comput. 1997 Feb;14(1):37–42. doi: 10.1007/BF03356577. [DOI] [PubMed] [Google Scholar]
- Kuper I. H., van Leeuwen M. A., van Riel P. L., Sluiter W. J., Houtman N. M., Cats H. A., van Rijswijk M. H. Influence of a ceiling effect on the assessment of radiographic progression in rheumatoid arthritis during the first 6 years of disease. J Rheumatol. 1999 Feb;26(2):268–276. [PubMed] [Google Scholar]
- Malliani A., Pagani M., Lombardi F., Cerutti S. Cardiovascular neural regulation explored in the frequency domain. Circulation. 1991 Aug;84(2):482–492. doi: 10.1161/01.cir.84.2.482. [DOI] [PubMed] [Google Scholar]
- Mancia G., Parati G., Castiglioni P., di Rienzo M. Effect of sinoaortic denervation on frequency-domain estimates of baroreflex sensitivity in conscious cats. Am J Physiol. 1999 Jun;276(6 Pt 2):H1987–H1993. doi: 10.1152/ajpheart.1999.276.6.H1987. [DOI] [PubMed] [Google Scholar]
- Novak V., Novak P., deMarchie M., Schondorf R. The effect of severe brainstem injury on heart rate and blood pressure oscillations. Clin Auton Res. 1995 Feb;5(1):24–30. doi: 10.1007/BF01845495. [DOI] [PubMed] [Google Scholar]
- Pagani M., Somers V., Furlan R., Dell'Orto S., Conway J., Baselli G., Cerutti S., Sleight P., Malliani A. Changes in autonomic regulation induced by physical training in mild hypertension. Hypertension. 1988 Dec;12(6):600–610. doi: 10.1161/01.hyp.12.6.600. [DOI] [PubMed] [Google Scholar]
- Parati G., Di Rienzo M., Bertinieri G., Pomidossi G., Casadei R., Groppelli A., Pedotti A., Zanchetti A., Mancia G. Evaluation of the baroreceptor-heart rate reflex by 24-hour intra-arterial blood pressure monitoring in humans. Hypertension. 1988 Aug;12(2):214–222. doi: 10.1161/01.hyp.12.2.214. [DOI] [PubMed] [Google Scholar]
- Porret C. A., Stergiopulos N., Hayoz D., Brunner H. R., Meister J. J. Simultaneous ipsilateral and contralateral measurements of vasomotion in conduit arteries of human upper limbs. Am J Physiol. 1995 Dec;269(6 Pt 2):H1852–H1858. doi: 10.1152/ajpheart.1995.269.6.H1852. [DOI] [PubMed] [Google Scholar]
- Tulen J. H., Man in 't Veld A. J., Van Roon A. M., Moleman P., Van Steenis H. G., Blankestijn P. J., Boomsma F. Spectral analysis of hemodynamics during infusions of epinephrine and norepinephrine in men. J Appl Physiol (1985) 1994 May;76(5):1914–1921. doi: 10.1152/jappl.1994.76.5.1914. [DOI] [PubMed] [Google Scholar]
- Winchell R. J., Hoyt D. B. Analysis of heart-rate variability: a noninvasive predictor of death and poor outcome in patients with severe head injury. J Trauma. 1997 Dec;43(6):927–933. doi: 10.1097/00005373-199712000-00010. [DOI] [PubMed] [Google Scholar]
- deBoer R. W., Karemaker J. M., Strackee J. Hemodynamic fluctuations and baroreflex sensitivity in humans: a beat-to-beat model. Am J Physiol. 1987 Sep;253(3 Pt 2):H680–H689. doi: 10.1152/ajpheart.1987.253.3.H680. [DOI] [PubMed] [Google Scholar]