Introduction: An existing monitoring database of brain signal recordings in patients with head injury has been re-evaluated with regard to the accuracy of estimation of non-invasive ICP (nICP) and its components, with a particular interest in the implications for outcome after head injury.
Methods: Middle cerebral artery blood flow velocity (FV), ICP and arterial blood pressure (ABP) were recorded. Non-invasive ICP (nICP) was calculated using a mathematical model. Other signals analysed included components of ICP (n” indicates non-invasive): ICP pulse amplitude (Amp, nAmp), amplitude of the respiratory component (Resp, nResp), amplitude of slow vasogenic waves of ICP (Slow, nSlow) and index of compensatory reserve (RAP, nRAP). Mean values of analysed signals were compared against each other and between patients who died and survived.
Results: The correlation between ICP and nICP was moderately strong, R = 0.51 (95% prediction interval [PI] 17 mm Hg). The components of nICP and ICP were also moderately correlated with each other: the strongest correlation was observed for Resp vs. nResp (r = 0.66), while weaker for Amp vs. nAmp (r = 0.41). Non-invasive pulse amplitude of ICP showed the strongest association with outcome, with the difference between those who survived and those who died reaching a significance level of p < 0.000001.
Discussion: When compared between patients who died and who survived mean nAmp showed the greatest difference, suggesting its potential to predict mortality after TBI.
Intracranial pressure Non-invasive ICP Pulse amplitude of intracranial pressure Slow waves of intracranial pressure Traumatic brain injury Outcome
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Conflict of interest
KPB was sponsored by the Graduate Travel and Research Fund of St. Catharine’s College, University of Cambridge, UK and the Clifford and Mary Corbridge Trust. ICM+ software is licensed by the University of Cambridge, Cambridge Enterprise Ltd. PS and MC have a financial interest in a part of its licensing fee. Non-invasive ICP Plugin is protected by patent DE 19600983. BS and MC have a financial interest in part of its licensing fee.
Avezaat CJ, van Eijndhoven JH, Wyper DJ (1979) Cerebrospinal fluid pulse pressure and intracranial volume-pressure relationships. J Neurol Neurosurg Psychiatry 42:687–700PubMedCrossRefGoogle Scholar
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) 146:131–141CrossRefGoogle Scholar
Czosnyka M, Guazzo E, Whitehouse M, Smielewski P, Czosnyka Z, Kirkpatrick P, Piechnik S, Pickard JD (1996) Significance of intracranial pressure waveform analysis after head injury. Acta Neurochir (Wien) 138:531–541, discussion 541–532CrossRefGoogle Scholar
Czosnyka M, Smielewski P, Kirkpatrick P, Laing RJ, Menon D, Pickard JD (1997) Continuous assessment of the cerebral vasomotor reactivity in head injury. Neurosurgery 41:11–17, discussion 17–19PubMedCrossRefGoogle Scholar
Czosnyka M, Smielewski P, Timofeev I, Lavinio A, Guazzo E, Hutchinson P, Pickard JD (2007) Intracranial pressure: more than a number. Neurosurg Focus 22:E10PubMedGoogle Scholar
Geeraerts T, Duranteau J, Benhamou D (2008) Ocular sonography in patients with raised intracranial pressure: the papilloedema revisited. Crit Care 12:150PubMedCrossRefGoogle Scholar
Jonas JB, Pfeil K, Chatzikonstantinou A, Rensch F (2008) Ophthalmodynamometric measurement of central retinal vein pressure as surrogate of intracranial pressure in idiopathic intracranial hypertension. Graefes Arch Clin Exp Ophthalmol 246:1059–1060PubMedCrossRefGoogle Scholar
Kim DJ, Czosnyka Z, Keong N, Radolovich DK, Smielewski P, Sutcliffe MP, Pickard JD, Czosnyka M (2009) Index of cerebrospinal compensatory reserve in hydrocephalus. Neurosurgery 64:494–501, discussion 501–492PubMedCrossRefGoogle Scholar
Lundberg N (1960) Continuous recording and control of ventricular fluid pressure in neurosurgical practice. Acta Psychiatr Scand Suppl 36:1–193PubMedGoogle Scholar
Ragauskas A, Daubaris G, Dziugys A, Azelis V, Gedrimas V (2005) Innovative non-invasive method for absolute intracranial pressure measurement without calibration. Acta Neurochir Suppl 95:357–361PubMedCrossRefGoogle Scholar
Reid A, Marchbanks RJ, Bateman DE, Martin AM, Brightwell AP, Pickard JD (1989) Mean intracranial pressure monitoring by a non-invasive audiological technique: a pilot study. J Neurol Neurosurg Psychiatry 52:610–612PubMedCrossRefGoogle Scholar
Schmidt B, Klingelhofer J, Schwarze JJ, Sander D, Wittich I (1997) Noninvasive prediction of intracranial pressure curves using transcranial Doppler ultrasonography and blood pressure curves. Stroke 28:2465–2472PubMedCrossRefGoogle Scholar
Schmidt B, Czosnyka M, Raabe A, Yahya H, Schwarze JJ, Sackerer D, Sander D, Klingelhofer J (2003) Adaptive noninvasive assessment of intracranial pressure and cerebral autoregulation. Stroke 34:84–89PubMedCrossRefGoogle Scholar
Shimbles S, Dodd C, Banister K, Mendelow AD, Chambers IR (2005) Clinical comparison of tympanic membrane displacement with invasive intracranial pressure measurements. Physiol Meas 26:1085–1092PubMedCrossRefGoogle Scholar
Voulgaris SG, Partheni M, Kaliora H, Haftouras N, Pessach IS, Polyzoidis KS (2005) Early cerebral monitoring using the transcranial Doppler pulsatility index in patients with severe brain trauma. Med Sci Monit 11:CR49–CR52PubMedGoogle Scholar
Xu P, Kasprowicz M, Bergsneider M, Hu X (2010) Improved noninvasive intracranial pressure assessment with nonlinear kernel regression. IEEE Trans Inf Technol Biomed 14:971–978PubMedCrossRefGoogle Scholar