Cerebral Hemodynamics and Intracranial Compliance Impairment in Critically Ill Covid-19 Patients: A Pilot Study

Abstract

Introduction: One of the possible mechanisms by which the new coronavirus (SARS-Cov2) could induce brain damage is the impairment of cerebrovascular hemodynamics (CVH) and intracranial compliance (ICC) due to the elevation of intracranial pressure (ICP). The main objective of this study was to assess the presence of CVH and ICC alterations in patients with COVID-19 and evaluate their association with short-term clinical outcome.Methods: 50 consecutive critically ill COVID-19 patients were studied with transcranial Doppler (TCD) and a non-invasive monitoring of ICC. Subjects were included upon ICU admission; CVH was evaluated using mean flow velocities in the middle cerebral arteries (mCBFV), pulsatility index (PI) and estimated cerebral perfusion pressure (eCPP) while ICC was assessed by using the P2/P1 ratio of estimated ICP curve (B4C device). The primary composite outcome was unsuccessful weaning from respiratory support or death on day 7.Results: At the first assessment (n= 50) only P2/P1 (1.20 [1.00-1.28] vs. 1.00 [0.88-1.16]; p=0.03) and eICP (14 [11-25] vs. 11 [7-15] mmHg; p=0.01) were significantly higher among patients with unfavorable outcome (UO) than others. Patients with UO had a significantly higher CVH/ICC score (9 [8-12] vs. 6 [5-7]; p<0.001) than those with favorable outcome; the area under the receiver operating curve (AUROC) for CVH/ICC score to predict UO was 0.86 (95% CIs 0.75-0.97); a score > 8.5 had 63 (46-77)% sensitivity and 87 (62-97)% specificity to predict UO. For those patients undergoing a second assessment (n=29) after a median of 11 (5-31) days, all measured variables were similar between the two time-points. No differences in the measured variables between ICU non-survivors (n=30) and survivors were observed.Conclusions: ICCI and CVH disturbances are often present in COVID-19 severe illness and could accurately predict early poor outcome.

A Novel Noninvasive Technique for Intracranial Pressure Waveform Monitoring in Critical Care

“…The first clinical study that applied this new technology successfully correlated the P2/P1 ratio with ICP in children with hydrocephalus [24], whereas another study assessed cerebrovascular disorders using transcranial Doppler and B4C devices in patients with severe COVID-19. In this study, a progressive score from 5 to 20 was created by combining the results of both techniques, indicating that the worse the cerebral hemodynamics and B4C P2/P1 ratio alterations, the higher the probability of either the impossibility of mechanical ventilation weaning or even death until seven days after examinations (p < 0.00001) [37], with a B4C P2/P1 ratio alteration, observed more frequently among patients who are obese (p = 0.029) [38]. Another study has observed an elevation in the P2/P1 ratio and TTP features extracted from B4C waveforms in patients with end-stage renal disease before and after hemodialysis sessions (p < 0.01), suggesting that ICC is disturbed in these patients [39].…”

A Novel Noninvasive Technique for Intracranial Pressure Waveform Monitoring in Critical Care

“…The first clinical study that applied this new technology successfully correlated the P2/P1 ratio with ICP in children with hydrocephalus [24], whereas another study assessed cerebrovascular disorders using transcranial Doppler and B4C devices in patients with severe COVID-19. In this study, a progressive score from 5 to 20 was created by combining the results of both techniques, indicating that the worse the cerebral hemodynamics and B4C P2/P1 ratio alterations, the higher the probability of either the impossibility of mechanical ventilation weaning or even death until seven days after examinations (P<0.00001) [37], with B4C P2/P1 ratio alteration observed more frequently among patients who are obese (P=0.029) [38].…”