Point of care ultrasound evaluation of cardio-cerebral coupling

Abstract

Cardio-cerebral coupling (CCC) refers to the dynamic interplay between cardiac function and cerebral blood flow, essential for maintaining hemodynamic stability. Disruptions in CCC are particularly relevant in critical care, where they can exacerbate primary and secondary brain injuries. Ultrasound-based techniques, including transcranial Doppler, transcranial color-coded Doppler, and echocardiography, provide non-invasive methods to assess this relationship at the bedside. This scoping review explores the pathophysiology of CCC, ultrasound methodologies for its evaluation, and its clinical relevance. Key mechanisms such as cerebral autoregulation and neurovascular coupling are discussed, along with ultrasound-derived parameters like pulsatility index, resistance index, and cerebral perfusion pressure. While ultrasound is a valuable tool, its limitations include operator dependency and equipment variability. Emerging evidence suggests that ultrasound-guided protocols, including ultrasound-guided cardio-cerebral resuscitation protocol and ultrasound-guided brain injury treatment protocol, may improve resuscitation strategies and neurocritical care monitoring. Despite its potential, further research is necessary to standardize assessment methods and integrate ultrasound-based CCC evaluation into routine clinical practice. Ongoing multicenter studies are expected to provide robust evidence supporting its clinical utility in managing brain-injured patients.

Keywords: Cardio-cerebral coupling; Transcranial Doppler; Echocardiography; Cerebral blood flow physiology; Cardiovascular physiology; Cerebral autorregulation; Brain circulation assessment

Core Tip: Cardio-cerebral coupling represents the dynamic interplay between cardiac function and cerebral blood flow regulation, crucial for maintaining hemodynamic stability. This article highlights the role of point-of-care ultrasound, including transcranial Doppler, transcranial color-coded Doppler, and echocardiography, in assessing cardio-cerebral coupling at bedside. Ultrasound-derived indices such as pulsatility index, resistance index, and cerebral perfusion pressure offer valuable insights into cerebral autoregulation. While ultrasound is a powerful tool, its clinical utility remains limited by operator dependency and methodological variability. Standardized protocols show promise in optimizing resuscitation strategies and neurocritical care. Further multicenter studies are needed to establish its role in routine clinical practice.