Advertisement

How Does Moderate Hypocapnia Affect Cerebral Autoregulation in Response to Changes in Perfusion Pressure in TBI Patients?

  • Christina Haubrich
  • Luzius Steiner
  • D. J. Kim
  • Magdalena Kasprowicz
  • Piotr Smielewski
  • Rolf R. Diehl
  • John D. Pickard
  • Marek Czosnyka
Chapter
Part of the Acta Neurochirurgica Supplementum book series (NEUROCHIRURGICA, volume 114)

Abstract

In traumatic brain injury, the hypocapnic effects on blood pressure autoregulation may vary from beneficial to detrimental. The consequences of moderate hypocapnia (HC) on the autoregulation of cerebral perfusion pressure (CPP) have not been monitored so far.

Thirty head injured patients requiring sedation and mechanical ventilation were studied during normocapnia (5.1 ± 0.4 kPa) and moderate HC (4.4 ± 3.0 kPa). Transcranial Doppler flow velocity (Fv) of the middle cerebral arteries (MCA), invasive arterial blood pressure, and intracranial pressure were monitored. CPP was calculated. The responsiveness of Fv to slow oscillations in CPP was assessed by means of the moving correlation coefficient, the Mx autoregulatory index. Hypocapnic effects on Mx were increasing with its deviation from normal baseline (left MCA: R 2 = 0.67; right MCA: R 2 = 0.51; p < 0.05). Mx indicating normal autoregulation (left: −0.23 ± 0.23; right: −0.21 ± 0.24) was not significantly changed by moderate HC. Impaired Mx autoregulation, however, (left: 0.37 ± 0.13; right: 0.33 ± 0.26) was improved (left: 0.12 ± 0.25; right: −0.0003 ± 0.19; p < 0.01) during moderate HC. Mx was adjusted to normal despite no significant change in CPP levels. Our study showed that short-term moderate HC may optimize the autoregulatory response to spontaneous CPP fluctuations with only a small CPP increase. Patients with impaired autoregulation seemed to benefit the most.

Keywords

Intracranial pressure Cerebral autoregulation Traumatic brain injury Moderate hypocapnia Transcranial Doppler 

Notes

Acknowledgements

The authors are in debt to the whole team participating in data collection and all the nursing and research staff at the Department of Neurosurgery.

Funding Disclosure

Dr. C Haubrich is supported by a Feodor-Lynen scholarship of the Alexander-von-Humboldt Foundation; Dr. M Kasprowicz is a scholar of the Foundation for Polish Science, Dr. M. Czosnyka and Dr. P. Smielewski are supported by MRC grant No.: G9439390, ID 65883. Dr. M. Czosnyka is on unpaid leave from Warsaw University.

Conflict of interest statement

ICM+software (www.neurosurg.cam.ac.uk/icmpluswww.neurosurg,cam,ac.uk/icmplus) is licensed by the University of Cambridge, UK, and P. Smielewski and M. Czosnyka have a financial interest in the licensing fee.

References

  1. 1.
    Czosnyka M, Smielewski P, Kirkpatrick P, Menon DK, Pickard JD (1996) Monitoring of cerebral autoregulation in head-injured patients. Stroke 27:1829–1834PubMedCrossRefGoogle Scholar
  2. 2.
    Miller JD, Becker DP (1982) Secondary insults to the injured brain. J R Coll Surg Edinb 27:292–298PubMedGoogle Scholar
  3. 3.
    Muizelaar JP, Ward JD, Marmarou A, Newlon PG, Wachi A (1989) Cerebral blood flow and metabolism in severely head injured children, part 2: autoregulation. J Neurosurg 71:72–76PubMedCrossRefGoogle Scholar
  4. 4.
    Bratton S, Chestnut RM, Ghajar J, McConnell Hammond FF, Harris OA, Hartl R, Manley GT, Nemecek A, Newell DW, Rosenthal G, Schouten J, Shutter L, Timmons SD, Ullman JS, Videtta W, Wilberger JE, Wright DW (2007) Hyperventilation. J Neurotrauma 24:S87–S90PubMedCrossRefGoogle Scholar
  5. 5.
    Piechnik SK, Yang X, Czosnyka M, Smielewski P, Fletcher SH, Jones AL, Pickard JD (1999) The continuous assessment of cerebrovascular reactivity: a validation of the method in healthy volunteers. Anesth Analg 89:944–949PubMedGoogle Scholar
  6. 6.
    Reinhard M, Roth M, Müller T, Guschlbauer B, Timmer J, Czosnyka M, Hetzel A (2004) Effect of carotid endarterectomy or stenting on impairment of dynamic cerebral autoregulation. Stroke 35:1381–1387PubMedCrossRefGoogle Scholar
  7. 7.
    Cold GE, Christensen MS, Schmidt K (1981) Effect of two levels of induced hypocapnia on cerebral autoregulation in the acute phase of head injury coma. Acta Anaesthesiol Scand 5:397–401CrossRefGoogle Scholar
  8. 8.
    Imberti R, Bellinzona G, Langer M (2002) Cerebral tissue PO2 and SjvO2 changes during moderate hyperventilation in patients with severe traumatic brain injury. J Neurosurg 96:97–102PubMedCrossRefGoogle Scholar
  9. 9.
    Newell DW, Weber JP, Watson R, Aaslid R, Winn HR (1996) Effect of transient moderate hyperventilation on dynamic cerebral autoregulation after severe head injury. Neurosurgery 1:35–43; discussion 43–34CrossRefGoogle Scholar
  10. 10.
    Møller K, Skinhøj P, Knudsen GM, Larsen FS (2000) Effect of short-term hyperventilation on cerebral blood flow autoregulation in patients with acute bacterial meningitis. Stroke 31:1116–1122PubMedCrossRefGoogle Scholar
  11. 11.
    Steiner LA, Balestreri M, Johnston AJ, Coles JP, Chatfield DA, Pickard JD, Menon DK, Czosnyka M (2005) Effects of moderate hyperventilation on cerebrovascular pressure-reactivity after head injury. Acta Neurochir Suppl 95:17–20PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag/Wien 2012

Authors and Affiliations

  • Christina Haubrich
    • 1
    • 2
  • Luzius Steiner
    • 3
  • D. J. Kim
    • 1
  • Magdalena Kasprowicz
    • 1
    • 4
  • Piotr Smielewski
    • 1
  • Rolf R. Diehl
    • 5
  • John D. Pickard
    • 1
  • Marek Czosnyka
    • 1
  1. 1.Department of Academic NeurosurgeryAddenbrooke’s HospitalCambridgeUK
  2. 2.Department of NeurologyUniversity Hospital AachenAachenGermany
  3. 3.Department of AnaesthesiaUniversity Hospital LausanneLausanneSwitzerland
  4. 4.Institute of Biomedical Engineering and InstrumentationWroclaw University of TechnologyWroclawPoland
  5. 5.Department of NeurologyAlfried-Krupp-KrankenhausEssenGermany

Personalised recommendations