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Concept of “true ICP” in monitoring and prognostication in head trauma

  • M. CzosnykaEmail author
  • L. Steiner
  • M. Balestreri
  • E. Schmidt
  • P. Smielewski
  • P. J. Hutchinson
  • J. D. Pickard
Part of the Acta Neurochirurgica Supplementum book series (NEUROCHIRURGICA, volume 95)

Summary

Objective

To propose a new coeffient, which contains information about both the absolute ICP and the position of the ‘working point’ on the pressure-volume curve.

Method

ICP was monitored continuously in 187 sedated and ventilated patients. The RAP coefficient was calculated as the running (3 minutes) correlation coefficient between slow changes in pulse amplitude and mean ICP. RAP has value 0 on the flat part of the Pressure-Volume Curve and +1 on the ascending exponential part. Then RAP decreases to zero or becomes negative when ICP increases further and affects cerebrovascular pressure-reactivity (which flattens the pressure-volume curve). Variable tICP=ICP*(1−RAP) has been called ‘trueICP’. It magnifies the critical values of ICP when cerebrovascular reactivity is exhausted and dampens those states where absolute ICP is elevated but vascular reactivity is not affected.

Results

Both Mean ICP and RAP were independently correlated with outcome (ANOVA:ICP-GOS: F=22; p<0.00001, RAPGOS: F=9; p<0.001). ‘TrueICP’ had stronger association with outcome: F=28; p<0.000001. Mortality in those patients having ‘trueICP’ above the threshold of 19 mm Hg was above 80%, while the mortality in those having cICP below 19 mm Hg was only 20% (F=80; p<10−8). ‘TrueICP’ was also suitable for continuous monitoring: sustained rise in tICP above 19 mm Hg was strongly associated with fatal complications.

Conclusion

The proposed variable is a powerful predictor of fatal outcome following head injury. It is sensitive to both the rising absolute ICP and the critical loss of cerebrovascular regulation.

Keywords

Intracranial pressure head injury monitoring outcome 

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References

  1. 1.
    Avezaat CJJ, van Eijndhoven JHM (1984) Cerebrospinal fluid pulse pressure and craniospinal dynamics. Thesis. A Jongbloed and Zoon Publishers, The HagueGoogle Scholar
  2. 2.
    Balestreri M, Czosnyka M, Steiner LA, Schmidt E, Smielewski P, Matta B, Pickard JD (2004) Intracranial hypertension: what additional information can be derived from ICP waveform after head injury? Acta Neurochir (Wien) 146(2): 131–141CrossRefGoogle Scholar
  3. 3.
    Eijndhoven JHM van, Avezaat CJJ (1986) Cerebrospinal fluid pulse pressure and the pulsatile variation in cerebral blood volume: an experimental study in dogs. Neurosurgery 19: 507–522PubMedGoogle Scholar
  4. 4.
    Langfitt TW, Weinstein JD, Kassell NF (1965) Cerebral vasomotor paralysis produced by intracranial pressure. Neurology (Minneap) 15: 622–641PubMedGoogle Scholar
  5. 5.
    Lofgren J, von Essen C, Zwetnow NN (1973) The pressurevolume curve of the cerebrospinal space in dogs. Acta Neurol Scand 49: 557–574PubMedCrossRefGoogle Scholar
  6. 6.
    Marmarou A, Maset AL, Ward JD, Choi S, Brooks D, Lutz HA, Moulton RJ, Muizelaar JP, DeSalles A, Young HF (1987) Contribution of CSF and vascular factors to elevation of ICP in severely head injured patients. J Neurosurg 66: 883–890PubMedCrossRefGoogle Scholar
  7. 7.
    Miller JD, Becker DP, Ward JD, Sullivan HG, Adams WE, Rosner MJ (1977) Significance of intracranial hypertension in severe head injury. J Neurosurg 47(4): 503–516PubMedCrossRefGoogle Scholar
  8. 8.
    Nornes H, Aaslid R, Lindegaard KF (1977) Intracranial pulse pressure dynamics in patients with intracranial hypertension. Acta Neurochirur (Wien) 38: 177–186CrossRefGoogle Scholar
  9. 9.
    Portnoy HD, Chopp M, Branch C, Shannon M (1982) Cerebrospinal fluid pulse waveform as an indicator of cerebral autoregulation. J Neurosurg 56: 666–678PubMedCrossRefGoogle Scholar
  10. 10.
    Smielewski P, Czosnyka M, Zabolotny W, Kirkpatrick P, Richards HK, Pickard JD (1997) A computing system for the clinical and experimental investigation of cerebrovascular reactivity. Int J Clin Monitor Comput 14: 185–198CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • M. Czosnyka
    • 1
    Email author
  • L. Steiner
    • 1
    • 2
  • M. Balestreri
    • 1
    • 3
  • E. Schmidt
    • 1
    • 4
  • P. Smielewski
    • 1
  • P. J. Hutchinson
    • 1
  • J. D. Pickard
    • 1
  1. 1.Academic Neurosurgical UnitAddenbrooke’s HospitalCambridgeUK
  2. 2.Department of AnaesthesiaUniversity Hospital BaselBaselSwitzerland
  3. 3.Department of Anaesthesia and Intensive Care (IInd) Policlinico San MatteoPaviaItaly
  4. 4.Department of NeurosurgeryHopital PurpanToulouseFrance

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