Applicability of near-infrared spectroscopy to measure cerebral autoregulation noninvasively in neonates: a validation study in piglets

TY - JOUR

T1 - Applicability of near-infrared spectroscopy to measure cerebral autoregulation noninvasively in neonates: a validation study in piglets

AU - Holst Hahn, Gitte

AU - Heiring, Christian

AU - Pryds, Ole

AU - Greisen, Gorm

PY - 2011/8

Y1 - 2011/8

N2 - Impaired cerebral autoregulation (CA) is common and is associated with brain damage in sick neonates. Frequency analysis using spontaneous changes in arterial blood pressure (ABP) and cerebral near-infrared spectroscopy (NIRS) has been used to measure CA in several clinical studies. Coherence of the NIRS and ABP signals (i.e. correlation in the frequency domain) detects impairment of CA, whereas gain (i.e. magnitude of ABP variability passing from systemic to cerebral circulation) estimates the degree of this impairment. So far, however, this method has not been validated. In 12 newborn piglets, we compared NIRS-derived measures of CA with a conventional measure of CA: cerebral blood flow was measured by laser Doppler flowmetry, and changes in ABP were induced by inflating a thoracic aorta balloon. CA capacity was calculated as %ACVR/%AABP (i.e. percentage of full autoregulatory capacity), where CVR (i.e. cerebral vascular resistance) was estimated as ABP/Doppler flux. Correlation between coherence and CA capacity (r = -0.34, n = 24, p < 0.05) and between gain and CA capacity (r = -0.11, n = 24, p > 0.05) was limited. As expected, however, gain was significantly associated with CA capacity in measurements with significant coherence (r = -0.55, n = 15, p = 0.03). In conclusion, our data validate frequency analysis for estimation of CA in clinical research. Low precision, however, hampers its clinical application.

AB - Impaired cerebral autoregulation (CA) is common and is associated with brain damage in sick neonates. Frequency analysis using spontaneous changes in arterial blood pressure (ABP) and cerebral near-infrared spectroscopy (NIRS) has been used to measure CA in several clinical studies. Coherence of the NIRS and ABP signals (i.e. correlation in the frequency domain) detects impairment of CA, whereas gain (i.e. magnitude of ABP variability passing from systemic to cerebral circulation) estimates the degree of this impairment. So far, however, this method has not been validated. In 12 newborn piglets, we compared NIRS-derived measures of CA with a conventional measure of CA: cerebral blood flow was measured by laser Doppler flowmetry, and changes in ABP were induced by inflating a thoracic aorta balloon. CA capacity was calculated as %ACVR/%AABP (i.e. percentage of full autoregulatory capacity), where CVR (i.e. cerebral vascular resistance) was estimated as ABP/Doppler flux. Correlation between coherence and CA capacity (r = -0.34, n = 24, p < 0.05) and between gain and CA capacity (r = -0.11, n = 24, p > 0.05) was limited. As expected, however, gain was significantly associated with CA capacity in measurements with significant coherence (r = -0.55, n = 15, p = 0.03). In conclusion, our data validate frequency analysis for estimation of CA in clinical research. Low precision, however, hampers its clinical application.

U2 - http://dx.doi.org/10.1203/PDR.0b013e3182231d9e

DO - http://dx.doi.org/10.1203/PDR.0b013e3182231d9e

M3 - Journal article

SN - 0031-3998

VL - 70

SP - 166

EP - 170

JO - Pediatric Research

JF - Pediatric Research

IS - 2

ER -