Comparison of optical measurements of critical closing pressure acquired before and during induced ventricular arrhythmia in adults

Abstract

. Significance: The critical closing pressure (CrCP) of cerebral circulation, as measured by diffuse correlation spectroscopy (DCS), is a promising biomarker of intracranial hypertension. However, CrCP techniques using DCS have not been assessed in gold standard experiments. Aim: CrCP is typically calculated by examining the variation of cerebral blood flow (CBF) during the cardiac cycle (with normal sinus rhythm). We compare this typical CrCP measurement with a gold standard obtained during the drops in arterial blood pressure (ABP) caused by rapid ventricular pacing (RVP) in patients undergoing invasive electrophysiologic procedures. Approach: Adults receiving electrophysiology procedures with planned ablation were enrolled for DCS CBF monitoring. CrCP was calculated from CBF and ABP data by three methods: (1) linear extrapolation of data during RVP ( ; the gold standard); (2) linear extrapolation of data during regular heartbeats ( ); and (3) fundamental harmonic Fourier filtering of data during regular heartbeats ( ). Results: CBF monitoring was performed prior to and during 55 episodes of RVP in five adults. and demonstrated agreement ( , (95%CI, 0.72 to 1.38). Agreement between and was worse; was higher than (mean ± SD; ). Conclusions: Our results suggest that DCS-measured CrCP can be accurately acquired during normal sinus rhythm.

Optimizing a two-layer method for hybrid diffuse correlation spectroscopy and frequency-domain diffuse optical spectroscopy cerebral measurements in adults

“… 33 Recent work has shown the promise of using a SI model to recover the fast DCS measurements of pulsatile blood flow during the cardiac cycle to assess intracranial pressure. 62 – 66 The use of layered head models can improve accuracy at the cost of higher instability from correlation noise ( Fig. 9 ).…”

Diffuse Optical Monitoring of Cerebral Hemodynamics and Oxygen Metabolism during and after Cardiopulmonary Bypass: Hematocrit Correction and Neurological Vulnerability

“…The use of optical neuromonitoring may aid in monitoring the efficacy of therapeutic strategies to reduce inflammation, and subsequent injury, during and following CPB. Advanced optical techniques to non-invasively estimate intracranial pressure are under development and could provide further discrimination in the future [77][78][79][80][81][82].…”

Pathlength-selective, interferometric diffuse correlation spectroscopy (PaLS-iDCS)

“…As an alternative, diffuse correlation spectroscopy (DCS), a diffuse optical technique used to estimate microvascular perfusion 10 , allows for a non-invasive, continuous estimate of blood flow in the brain. DCS has been validated against several gold-standard perfusion monitoring techniques including arterial spin labeled MRI 11,12 , Xenon-CT 13 , positron emission tomography 14 , and tracer bolus tracking 15 , and has been used extensively in research to assess CBF in multiple clinical scenarios, including major cardiac surgeries [16][17][18][19] and longterm monitoring of acute brain injury in the neuro ICU 13,[20][21][22] . Traditionally, DCS has been performed using continuous wave illumination, which, due to the partial volume effect, intrinsically links the measurement source-detector separation (SDS), cerebral sensitivity, and signal-to-noise ratio of the measurement 23 .…”