Ultrasound-tagged near-infrared spectroscopy does not disclose absent cerebral circulation in brain-dead adults

A. Caccioppola, M. Carbonara, M. Macrì, L. Longhi, S. Magnoni, F. Ortolano, F. Triulzi, E. R. Zanier, T. Zoerle, N. Stocchetti

Research output: Contribution to journalArticlepeer-review

Abstract

Background: Near-infrared spectroscopy, a non-invasive technique for monitoring cerebral oxygenation, is widely used, but its accuracy is questioned because of the possibility of extra-cranial contamination. Ultrasound-tagged near-infrared spectroscopy (UT-NIRS) has been proposed as an improvement over previous methods. We investigated UT-NIRS in healthy volunteers and in brain-dead patients. Methods: We studied 20 healthy volunteers and 20 brain-dead patients with two UT-NIRS devices, CerOx™ and c-FLOW™ (Ornim Medical, Kfar Saba, Israel), which measure cerebral flow index (CFI), a parameter related to changes in cerebral blood flow (CBF). Monitoring started after the patients had been declared brain dead for a median of 34 (range: 11–300) min. In 11 cases, we obtained further demonstration of absent CBF. Results: In healthy volunteers, CFI was markedly different in the two hemispheres in the same subject, with wide variability amongst subjects. In brain-dead patients (median age: 64 yr old, 45% female; 20% traumatic brain injury, 40% subarachnoid haemorrhage, and 40% intracranial haemorrhage), the median (inter-quartile range) CFI was 41 (36–47), significantly higher than in volunteers (33; 27–36). Conclusions: In brain-dead patients, where CBF is absent, the UT-NIRS findings can indicate an apparently perfused brain. This might reflect an insufficient separation of signals from extra-cranial structures from a genuine appraisal of cerebral perfusion. For non-invasive assessment of CBF-related parameters, the near-infrared spectroscopy still needs substantial improvement.

Original languageEnglish
Pages (from-to)588-594
JournalBritish Journal of Anaesthesia
Volume121
Issue number3
DOIs
Publication statusPublished - 2018

Keywords

  • brain death
  • brain monitoring
  • cerebral blood flow
  • near-infrared spectroscopy
  • ultrasound-tagged near-infrared spectroscopy

ASJC Scopus subject areas

  • Anesthesiology and Pain Medicine

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