My Ph.D. research at the University of Cambridge focused on modelling of brain haemodynamics, particularly describing a terminal situation of cerebral circulation, associated with ischemic strokes. A new methodology was created which can be used for estimating brain’s zero-flow pressure or critical closing pressure (CrCP): a critical threshold for arterial blood pressure (ABP). If ABP falls below CrCP, the local blood pressure inside small vessels (microcirculation) is no longer adequate to keep them open, leading them to a collapse, ceasing blood flow.
The new methodology eliminated the main drawback of previous CrCP methods, which were presenting non-physiological negative values; CrCP can now instead be considered as a reliable tool for physicians. A new CrCP-based mechanism was further introduced, which can quantify the ischemic risk for a patient during haemodynamic changes, like intracranial hypertension or arterial hypotension. In neurointensive care, this mechanism might provide a reference point to guidance of treatment in terms of terminal ischemia associated with collapsing vessels.
Based on this mechanism, the phenomenon of absence of diastolic blood flow was explained as distally collapsed small cerebral vessels, associated with ABP going below CrCP during diastole, possibly then enhancing our understanding of this phenomenon, which could lead to an imminent circulatory arrest and brain death.
Research highlight achievements
- Eliminated the major 60-year drawback of previous methods rendering non-physiological values which were restricting the use of CrCP
- Gave a reliable and trustworthy method to medical professionals for assessing brain haemodynamics
- A total of 37 scientific papers were published, with 1,200+ citations
- New method set the basis of a $170K+ NIH research grant at Baylor College of Medicine, Houston, Texas [Diastolic closing margin predicts brain injury in premature infants; NIH 1K23NS091382-01A1]
1.Critical closing pressure during experimental intracranial hypertension: comparison of three calculation methods. Neurol Res. 2020 May;42(5):387-397.
2.Effect of Mild Hypocapnia on Critical Closing Pressure and Other Mechanoelastic Parameters of the Cerebrospinal System. Acta Neurochir Suppl. 2018; 126:139-142.
3.Critical Closing Pressure During a Controlled Increase in Intracranial Pressure. Acta Neurochir Suppl. 2018; 126:133-137.
4.Increased ICP and Its Cerebral Haemodynamic Sequelae. Acta Neurochir Suppl. 2018; 126:47-50.
5.Critical Closing Pressure During Controlled Increase in Intracranial Pressure – Comparison of Three Methods. IEEE Trans Biomed Eng. Mar 2018; 65(3):619-624.
6.Cerebral Haemodynamics during Experimental Intracranial Hypertension. J Cereb Blood Flow Metab. Feb 2017; 37(2):694-705.
7.Cerebral Critical Closing Pressure: Is the Multiparameter Model Better Suited to Estimate Physiology of Cerebral Hemodynamics? Neurocrit Care. Dec 2016; 25(3):446-454.
8.Elevated Diastolic Closing Margin Is Associated with Intraventricular Hemorrhage in Premature Infants. J Pediatr. July 2016; 174:52-6.
9.The Diastolic Closing Margin Is Associated with Intraventricular Hemorrhage in Premature Infants. Acta Neurochir Suppl. May 2016; 122:147-50.
10.The Ontogeny of Cerebrovascular Pressure Autoregulation in Premature Infants. Acta Neurochir Suppl. May 2016; 122:151-5.
11.Monitoring Cerebral Autoregulation After Subarachnoid Hemorrhage. Acta Neurochir Suppl. May 2016; 122:199-203.
12.Cerebral Critical Closing Pressure During Infusion Tests. Acta Neurochir Suppl. May 2016; 122:215-20.
13.Derangement of Cerebral Blood Flow Autoregulation During Intracranial Pressure Plateau Waves as Detected by Time and Frequency-Based Methods. Acta Neurochir Suppl. May 2016; 122:233-8.
14.The Ontogeny of Cerebrovascular Critical Closing Pressure. Acta Neurochir Suppl. May 2016; 122:249-53.
15.Measurement of Intraspinal Pressure After Spinal Cord Injury: Technical Note from the Injured Spinal Cord Pressure Evaluation Study. Acta Neurochir Suppl. May 2016; 122:323-8.
16.Waveform Analysis of Intraspinal Pressure After Traumatic Spinal Cord Injury: An Observational Study (O-64). Acta Neurochir Suppl. May 2016; 122:335-8.
17.Prospective Study on Non-invasive Assessment of Intracranial Pressure in Traumatic Brain-Injured Patients: Comparison of Four Methods. J Neurotrauma. Apr 2016; 33(8):792-802.
18.Intraspinal Pressure and Spinal Cord Perfusion Pressure after Spinal Cord Injury: an Observational Study. J Neurosurg Spine. Aug 2015; 14:1-9.
19.Cerebral Critical Closing Pressure in Hydrocephalus Patients undertaking Infusion Tests. Neurol Res. Aug 2015; 37(8):674-82.
20.Ontogeny of Cerebrovascular Critical Closing Pressure. Pediatr Res. Jul 2015; 78(1):71-5.
21.Expansion Duroplasty improves Intraspinal Pressure, Spinal Cord Perfusion Pressure and Vascular Pressure Reactivity Index in Patients with Traumatic Spinal Cord Injury. J Neurotrauma. Jun 2015; 32(12):865-74.
22.Comparison of Frequency and Time Domain Methods of Assessment of Cerebral Autoregulation in Traumatic Brain Injury. J Cereb Blood Flow Metab. Feb 2015; 35(2):248-56.
23.Cerebral Vasospasm affects Arterial Critical Closing Pressure. J Cereb Blood Flow Metab. Feb 2015; 35(2):285-91.
24.Increased Blood Glucose is related to Disturbed Cerebrovascular Pressure Reactivity after Traumatic Brain Injury. Neurocrit Care. Feb 2015; 22(1):20-5.
25.Bilateral Failure of Cerebral Autoregulation is related to Unfavorable Outcome after Subarachnoid Hemorrhage. Neurocrit Care. Feb 2015; 22(1):65-73.
26.A non-invasive estimation of Cerebral Perfusion Pressure using Critical Closing Pressure. J Neurosurg. Jan 2015; 9:1-11.
27.The Ontogeny of Cerebrovascular Pressure Autoregulation in Premature Infants. J Perinatol. Dec 2014; 34(12):926-31.
28.Relationship of Vascular Wall Tension and Autoregulation following Traumatic Brain Injury. Neurocrit Care. Oct 2014; 21(2):266-74.
29.Baroreflex and Cerebral Autoregulation are Inversely Correlated. Circ J. Sep 2014; 78(10):2460-7.
30.Repeatability of Cerebrospinal Fluid Constant Rate Infusion Study. Acta Neurol Scand. Aug 2014; 130(2):131-8.
31.Pressures, Flow, and Brain Oxygenation during Plateau Waves of Intracranial Pressure. Neurocrit Care. Aug 2014; 21(1):124-32.
32.Monitoring of Spinal Cord Perfusion Pressure in Acute Spinal Cord Injury: Initial Findings of the Injured Spinal Cord Pressure Evaluation Study. Crit Care Med. Mar 2014; 42(3):646-55.
33.Cessation of Diastolic Cerebral Blood Flow Velocity – the role of Critical Closing Pressure. Neurocrit Care. Feb 2014; 20(1):40-8.
34.Model-based Indices describing Cerebrovascular Dynamics. Neurocrit Care. Feb 2014; 20(1):142-57.
35.Critical Closing Pressure during Intracranial Pressure Plateau Waves. Neurocrit Care. Jun 2013; 18(3):341-8.
36.Cerebral Autoregulation after Subarachnoid Haemorrhage: Comparison of Three Methods. J Cereb Blood Flow Metab. Mar 2013; 33(3):449-56.
37.Critical Closing Pressure determined with a Model of Cerebrovascular Impedance. J Cereb Blood Flow Metab. Feb 2013; 33(2):235-43.
- Multi-Modal Monitoring for Brain Injury in Critically Ill Children. Pediatric Critical Care Medicine. May 2014; 15(Issue 4_suppl): 68, Abstract 290 – Abstracts of the 7th World Congress on Pediatric Critical Care
- Measurement and Optimisation of Spinal Cord Perfusion Pressure in Acute Spinal Cord Injury. British Journal of Neurosurgery. Oct 2013: 27(5):556, Abstract WM1-2 – Proceedings of the 2013 Autumn meeting of the Society of British Neurological Surgeons
- Improving the Physiological Interpretation of Cerebral Critical Closing Pressure. Cerebrovascular Diseases. May 2013; 35, Abstract O7 – 18th Meeting of the European Society of Neurosonology and Cerebral Hemodynamics and 3rd Meeting of the Cerebral Autoregulation Network
Invited manuscript Reviewer
- BioMedical Engineering OnLine
- Brain Sciences
- Neurocritical Care – received a Top Reviewer Award, October 2019
- Scientific Reports
- Trauma Cases and Reviews