Near-infrared spectroscopy to detect absence of cerebrovascular autoregulation in preterm infants.

OBJECTIVE

Our aim was to explore clinical parameters that might predict the absence of cerebrovascular autoregulation (CAR) assessed by a negative relationship between mean arterial blood pressure (MABP) and fractional tissue oxygen extraction (FTOE) as measured by near-infared spectroscopy (NIRS) in preterm infants.

METHODS

We included preterm infants (gestational age (GA) <32 weeks). Within 72 h after birth, we recorded the infants' NIRS parameters and MABP for a 24-h period. Fractional tissue oxygen extraction (FTOE) was calculated. For each infant we calculated Spearman rank (rho) correlations. A statistically significant negative correlation between MABP and FTOE indicated the absent CAR. We related the absent CAR to clinical parameters.

RESULTS

Ten (40%) out of 25 infants (median GA 29.1 weeks, range 25.4-31.7, birth weight 1245 g, 560-1780) had a statistically significant negative correlation between MABP and FTOE (rho -0.432 to -0.156), suggesting the absence of CAR. None of the clinical variables predicted the absence of CAR.

CONCLUSIONS

We were unable to predict the absence of CAR in terms of clinical variables. Nevertheless, we found a statistically significant negative correlation between MABP and FTOE using NIRS, suggesting the absence of CAR in almost half of the preterm infants studied.

SIGNIFICANCE

NIRS could be a helpful tool to assess the presence or absence of CAR.