Noninvasive optical measurement of microvascular cerebral hemodynamics and autoregulation in the neonatal ECMO patient

Abstract

Background Extra-Corporeal Membrane Oxygenation (ECMO) is a life-saving intervention for severe respiratory and cardiac diseases. However, 50% of survivors have abnormal neurologic exams. Current ECMO management is guided by systemic metrics, which may poorly predict cerebral perfusion. Continuous optical monitoring of cerebral hemodynamics during ECMO holds potential to detect risk factors of brain injury such as impaired cerebrovascular autoregulation ( CA ). Methods We conducted daily measurements of microvascular cerebral blood flow ( CBF ), oxygen saturation, and total hemoglobin concentration using diffuse correlation spectroscopy (DCS) and frequency-domain diffuse optical spectroscopy in 9 neonates. We characterize CA utilizing the correlation coefficient ( DCSx ) between CBF and mean arterial blood pressure ( MAP ) during ECMO pump flow changes. Results Average MAP and pump flow levels were weakly correlated with CBF and were not correlated with cerebral oxygen saturation. CA integrity varied between individuals and with time. Systemic measurements of MAP , pulse pressure, and left cardiac dysfunction were not predictive of impaired CA . Conclusions Our pilot results suggest that systemic measures alone cannot distinguish impaired CA from intact CA during ECMO. Furthermore, optical neuromonitoring could help determine patient-specific ECMO pump flows for optimal CA integrity, thereby reducing risk of secondary brain injury.

Microcirculatory Response to Changes in Venoarterial Extracorporeal Membrane Oxygenation Pump Flow: A Prospective Observational Study

“…The finding of contradictory decrease in PVD after increasing VA-EMCO pump flow is compatible with that of Busch et al (31). They suggest that cerebral blood flow and oxygenation are not well-predicted by VA-ECMO pump flow or blood pressure.…”

Continuous Monitoring of Cerebral Autoregulation in Children Supported by Extracorporeal Membrane Oxygenation: A Pilot Study

“…In this overall context, CA impairment in critically ill patients treated by ECMO may be a key factor in the genesis of neurological complications. Recent preliminary studies using different methods have suggested an association with CA disorders and neurological outcome among children supported by ECMO (13)(14)(15).…”

Asymmetric, dynamic adaptation in prefrontal cortex during dichotic listening tasks

“…In terms of optical intrinsic signals, the scattering changes measured in vivo for profound physiological perturbation (e.g., middle cerebral artery occlusion stroke model) are <5%. 62 Other causes of dramatic scattering change, e.g., edema, 65 have little effect on the time scale of this measurement. Given these findings, it seems reasonable to assume that scattering changes would be highly unlikely to influence the apparent BFI signals.…”