Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.763592
Title: Monitoring of cerebral oxygenation, cerebrovascular reactivity and circulatory function in preterm infants
Author: Sortica da Costa, Cristine
ISNI:       0000 0004 7651 9642
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2018
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Abstract:
Monitoring of cerebral oxygenation, cerebrovascular reactivity and circulatory function in preterm infants Brain injury in the preterm infant is associated with death and lifelong disability. Cerebral hypoxia and fluctuations in cerebral blood flow in the first two days of life have been implicated in the pathophysiology of haemorrhagic and ischaemic brain injury. Monitoring of haemodynamic changes during the early transitional circulation from in-utero to ex-utero life are currently based on standard measurements of systemic oxygenation and mean arterial blood pressure, with no reliable assessment of end-organ perfusion. In this thesis, measurements using near-infrared spectroscopy (NIRS) and functional echocardiography were made to assess cerebral perfusion and systemic blood flow in a cohort of preterm infants undergoing intensive care. This thesis is divided into four sections: i) The feasibility of continuous monitoring of cerebral oxygenation and cerebrovascular reactivity is demonstrated in a series of case reviews, and the association between cerebral oxygenation and cerebrovascular reactivity with outcome of brain injury and mortality is described. ii) Combining measurements of systemic blood flow with end organ perfusion was applied to define MABPOPT in preterm infants based on an index of cerebrovascular reactivity. Deviations below MABPOPT were associated with intraventricular haemorrhage and mortality. iii) The complexity of brain and systemic signals was studied by using multi-scale entropy analysis. Most studies using cerebral NIRS or systemic measurements of blood flow use linear analysis; however, a complex biological system, such as the human brain, includes many regulatory mechanisms that interact in a complex manner, resulting in effects that cannot be understood wholly through the analysis of its individual constituents. Lower complexity of brain signals was observed in infants who developed intraventricular hemorrhage or died. iv) Changes in systemic and cerebral oxygenation in a cohort of preterm infants in the first 48 hours of life was assessed using functional echocardiography. The patterns of changes in cardiac output and cerebral oxygenation in infants who did and did not have intraventricular haemorrhage are discussed. Furthermore, the relationship between the presence of a haemodynamically significant ductus arteriosus and brain injury is assessed.
Supervisor: Austin, Topun ; Czosnyka, Marek Sponsor: Cambridge Overseas Trust ; CAPES
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.763592  DOI:
Keywords: Prematurity ; Cerebral autoregualtion ; Cerebrovascular reactivity ; Arterial blood pressure ; NIRS ; Brain injury ; Functional echocardiography
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