Innovative non-invasive method for absolute intracranial pressure measurement without calibration

Ragauskas, Arminas; Daubaris, Gediminas; Džiugys, Algis; Azelis, V.; Gedrimas, Vytautas Leonas

doi:10.1007/3-211-32318-x_73

Cited by 58 publications

(51 citation statements)

References 11 publications

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“…However, most of these correlation-based methods had the same problem—the need of individual patient specific calibration. Seeking to measure absolute ICP values, researchers from Kaunas University of Technology created noninvasive method, which does not need a patient specific calibration [17, 18]. The method is based on direct comparison of ICP value with the value of pressure Pe that is externally applied to the tissues surrounding the eyeball.…”

Section: Introductionmentioning

confidence: 99%

The Difference in Translaminar Pressure Gradient and Neuroretinal Rim Area in Glaucoma and Healthy Subjects

Šiaudvytytė

Janulevičienė

Ragauskas

et al. 2014

Journal of Ophthalmology

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Purpose. To assess differences in translaminar pressure gradient (TPG) and neuroretinal rim area (NRA) in patients with normal tension glaucoma (NTG), high tension glaucoma (HTG), and healthy controls. Methods. 27 patients with NTG, HTG, and healthy controls were included in the prospective pilot study (each group consisted of 9 patients). Intraocular pressure (IOP), intracranial pressure (ICP), and confocal laser scanning tomography were assessed. TPG was calculated as the difference of IOP minus ICP. ICP was measured using noninvasive two-depth transcranial Doppler device. The level of significance P < 0.05 was considered significant. Results. NTG patients had significantly lower IOP (13.7(1.6) mmHg), NRA (0.97(0.36) mm2), comparing with HTG and healthy subjects, P < 0.05. ICP was lower in NTG (7.4(2.7) mmHg), compared with HTG (8.9(1.9) mmHg) and healthy subjects (10.5(3.0) mmHg); however, the difference between groups was not statistically significant (P > 0.05). The difference between TPG for healthy (5.4(7.7) mmHg) and glaucomatous eyes (NTG 6.3(3.1) mmHg, HTG 15.7(7.7) mmHg) was statistically significant (P < 0.001). Higher TPG was correlated with decreased NRA (r = −0.83; P = 0.01) in the NTG group. Conclusion. Translaminar pressure gradient was higher in glaucoma patients. Reduction of NRA was related to higher TPG in NTG patients. Further prospective studies are warranted to investigate the involvement of TPG in glaucoma management.

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Section: Introductionmentioning

confidence: 99%

The Difference in Translaminar Pressure Gradient and Neuroretinal Rim Area in Glaucoma and Healthy Subjects

Šiaudvytytė

Janulevičienė

Ragauskas

et al. 2014

Journal of Ophthalmology

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“…However, there are a few papers in which gauge pressure is erroneously treated as Babsolute intracranial pressure ( Ragauskas et al 2005;Nusbaum 2011;Siaudvytyte et al 2015). In those studies, the intracranial pressure measurements taken noninvasively by means of a two-depth transcranial Doppler method are calculated indirectly on the basis of blood flow velocities in the intracranial and extracranial segments of the ophthalmic artery after applying external pressure over the orbital sclera via inflatable cuff where the tension is gradually increasing by a few mmHg from 0 to 20-28 mmHg.…”

Section: Discussionmentioning

confidence: 99%

The major influence of the atmosphere on intracranial pressure: an observational study

Herbowski¹

2016

Int J Biometeorol

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The impact of the atmosphere on human physiology has been studied widely within the last years. In practice, intracranial pressure is a pressure difference between intracranial compartments and the surrounding atmosphere. This means that gauge intracranial pressure uses atmospheric pressure as its zero point, and therefore, this method of pressure measurement excludes the effects of barometric pressure's fluctuation. The comparison of these two physical quantities can only take place through their absolute value relationship. The aim of this study is to investigate the direct effect of barometric pressure on the absolute intracranial pressure homeostasis. A prospective observational cross-sectional open study was conducted in Szczecin, Poland. In 28 neurosurgical patients with suspected normal-pressure hydrocephalus, intracranial intraventricular pressure was monitored in a sitting position. A total of 168 intracranial pressure and atmospheric pressure measurements were performed. Absolute atmospheric pressure was recorded directly. All values of intracranial gauge pressure were converted to absolute pressure (the sum of gauge intracranial pressure and local absolute atmospheric pressure). The average absolute mean intracranial pressure in the patients is 1006.6 hPa (95 % CI 1004.5 to 1008.8 hPa, SEM 1.1), and the mean absolute atmospheric pressure is 1007.9 hPa (95 % CI 1006.3 to 1009.6 hPa, SEM 0.8). The observed association between atmospheric and intracranial pressure is strongly significant (Spearman correlation r = 0.87, p < 0.05) and all the measurements are perfectly reliable (Bland-Altman coefficient is 4.8 %). It appears from this study that changes in absolute intracranial pressure are related to seasonal variation. Absolute intracranial pressure is shown to be impacted positively by atmospheric pressure.

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“…The 95% confidence range for predictors was Ϯ12 mm Hg for the CPP, varying from 70 to 95 mm Hg. Attempts at estimation of ICP have demonstrated similar confidence intervals (47). Unfortunately, these values are still unacceptable for clinical purposes.…”

Section: Tcd In Traumatic Brain Injury: Intracranial Pressure and Cermentioning

confidence: 97%

Role of transcranial Doppler in neurocritical care

Saqqur

Zygun

Demchuk

2007

Critical Care Medicine

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Transcranial Doppler has several practical applications in neurocritical care. It has its main application in the diagnosis and monitoring of vasospasm in patients with subarachnoid hemorrhage. In addition, it holds promise for the detection of critical elevations of intracranial pressure. Its ability to measure CO2 reactivity and autoregulation may ultimately allow intensivists to optimize cerebral perfusion pressure and ventilatory therapy for the individual patient. Transcranial Doppler findings of brain death are well described and can be useful as a screening tool.

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Innovative non-invasive method for absolute intracranial pressure measurement without calibration

Cited by 58 publications

References 11 publications

The Difference in Translaminar Pressure Gradient and Neuroretinal Rim Area in Glaucoma and Healthy Subjects

The Difference in Translaminar Pressure Gradient and Neuroretinal Rim Area in Glaucoma and Healthy Subjects

The major influence of the atmosphere on intracranial pressure: an observational study

Role of transcranial Doppler in neurocritical care

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