Thesis (Ph.D.) - Cairo University - Faculty of Medicine - Department of Pediatrics

Background:Sepsis-associated encephalopathy (SAE) is one of the most common causes of delirium in intensive care units. Its pathophysiology is complex and related to numerous processes and pathways.Alterations of the cerebral blood flow (CBF) may represent a key component for the development of SAE which may be caused by cerebral vasoconstriction. Transcranial Doppler (TCD) allows real-time accurate detection of CBF. Objectives:to assess changes in cerebral hemodynamic characteristics in pediatric septic encephalopathy patients Methodology: a prospective case control study including 75 critically ill children; 45 patients were diagnosed as severe sepsis or septic shock with encephalopathy, while the other 30 critically ill patients who were neither septic nor encephalopathic served as control.Patients were examined using the TCD on the middle cerebral artery.Pulsatility (PI) and resistive (RI) indices were measured to assess the cerebrovascular resistance (CVR). Results:cerebrovascular resistance (CVR) was higher in the septic group. This is evidenced by significantly higher PI and RI in the septic encephalopathic group than controlone (P<0.01). CO2 reactivity was impaired as there was positive statistically significant correlation between both PI and RI, and PaCO2 (r=0.4, P<0.01 and r=0.374, P=0.01 respectively). The level of consciousness of the patients was assessed by FOUR score; PI was negatively correlated to FOUR score with high significance (r = -0.357, and P=0.016). This means that pulsatility index increased with the more deepening of coma. PI and RI were significantly higher in the non-survivor cases than the survivor ones (P<0.01). By using a regression analysis method; PI was an independent risk of mortality with (O.R= 257, 95%CI= 6.1-108, P<0.01) Conclusion:in pediatric patients with SAE; CVR is higher with decreased cerebral blood flow and CO2 reactivity is impaired

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