We propose to study the different phenotypes of transcranial doppler (TCD) derived cerebral blood flow velocity parameters in Indian children with sepsis or septic shock and its association with the clinical outcome in these children.

Dysregulated, self-sustaining, and uncontrolled intravascular inflammation during sepsis lead to rapidly progressing end organ dysfunction culminating in septic shock and multi organ dysfunction. Research in children revealed loss of hemodynamic coherence, i.e., microcirculatory alterations despite normal systemic haemodynamics. Cerebral microcirculation is gradually compromised during sepsis, with significant reductions in the function of capillaries and blood perfusion in small vessels. To develop efficacious adjunctive therapeutic approaches that improve outcomes in paediatric sepsis, mechanisms of neurological injury must be determined. Transcranial Doppler Ultrasound (TCD) is a portable, non-invasive method to assess the cerebral blood flow velocities (CBFVs) and haemodynamics in the major cerebral vessels. The measurement of CBF velocity (CBFV) with TCD can be considered a surrogate of CBF, if it is assumed that the diameter of the vessel remains constant. Therefore, the changes in CBFV detected by TCD could represent the hemodynamic changes mediated by microcirculation. TCD derived CBFVs and morphologic waveforms are determined by the mean arterial pressure, the tone and patency of the systemic and cerebral vessels, and the intracranial and central venous pressures. Alterations to any of these factors results in distinct changes to measured TCD parameters and waveform morphology. Thus, TCD is used as a point of care tool to determine specific mechanisms of focal or global cerebral dysfunction in several clinical scenarios. The rationale behind doing this study is to look for different patterns in TCD derived cerebral hemodynamic parameters in children with septic shock in PICU.

This study is to be done in children of 1 – 18 years age group being admitted in PICU with sepsis or septic shock. Cerebral blood flow velocities, pulsatility index and resistive index will be recorded using transcranial doppler ultrasound at predetermined intervals. Different phenotypes of TCD derived cerebral blood flow velocities in children with sepsis or septic shock will be evaluated. Its correlation with the hemodynamic parameters and its association with the clinical outcomes in pediatric septic shock will be studied.