Color doppler evaluation of the influence of type of delivery, sex, postnatal age and time post feeding on full term healthy newborns cerebral blood flow

Quantification of brain-wide vascular resistivity via ultrafast Doppler in human neonates helps early detection of white matter injury

Preterm birth is associated with cerebrovascular development disruption and can induce white matter injuries (WMI). Transfontanellar ultrasound Doppler is the most widely used clinical imaging technique to monitor neonatal cerebral vascularisation and haemodynamics based on vascular indexes such as the resistivity index (RI); however, it has poor predictive value for brain damage. Indeed, these RI measurements are currently limited to large vessels, leading to a very limited probing of the brain's vascularisation, which may hinder prognosis. Here we show that ultrafast Doppler imaging (UfD) enables simultaneous quantification, in the whole field of view, of the local RI and vessel diameter, even in small vessels. Combining both pieces of information, we defined two new comprehensive resistivity parameters of the vascular trees. First, we showed that our technique is more sensitive in the early characterisation of the RI modifications between term and preterm neonates and for the first time we could show that the RI depends both on the vessel diameter and vascular territory. We then showed that our parameters can be used for early prediction of WMI. Our results demonstrate the potential of UfD to provide new biomarkers and pave the way for continuous monitoring of neonatal brain resistivity.

Low frequency cerebral arterial and venous flow oscillations in healthy neonates measured by NeoDoppler

BACKGROUND

A cerebroprotective effect of low frequency oscillations (LFO) in cerebral blood flow (CBF) has been suggested in adults, but its significance in neonates is not known. This observational study evaluates normal arterial and venous cerebral blood flow in healthy neonates using NeoDoppler, a novel Doppler ultrasound system which can measure cerebral hemodynamics continuously.

METHOD

Ultrasound Doppler data was collected for 2 h on the first and second day of life in 36 healthy term born neonates. LFO (0.04-0.15 Hz) were extracted from the velocity curve by a bandpass filter. An angle independent LFO index was calculated as the coefficient of variation of the filtered curve. Separate analyses were done for arterial and venous signals, and results were related to postnatal age and behavioral state (asleep or awake).

RESULTS

The paper describes normal physiologic variations of arterial and venous cerebral hemodynamics. Mean (SD) arterial and venous LFO indices (%) were 6.52 (2.55) and 3.91 (2.54) on day one, and 5.60 (1.86) and 3.32 (2.03) on day two. After adjusting for possible confounding factors, the arterial LFO index was estimated to decrease by 0.92 percent points per postnatal day (p < 0.001). The venous LFO index did not change significantly with postnatal age (p = 0.539). Arterial and venous LFO were not notably influenced by behavioral state.

CONCLUSION

The results indicate that arterial LFO decrease during the first 2 days of life in healthy neonates. This decrease most likely represents normal physiological changes related to the transitional period. A similar decrease for venous LFO was not found.

Early Use of Transcranial Doppler Ultrasonography to Stratify Neonatal Encephalopathy

BACKGROUND

The dynamic nature of neonatal hypoxic-ischemic encephalopathy (HIE) after birth necessitates reliable biomarkers to identify infants with evolving brain injury. This prospective cohort aims to use serial Doppler ultrasonography (US) to measure cerebral blood flow velocity and resistance index (RI) to help detect the time and evolution of the clinical encephalopathy.

METHODS

A total of 60 neonates were enrolled all ≥36 weeks' gestation with perinatal acidemia, defined as a blood gas pH ≤ 7.0 or base deficit ≥16 mmol/L and encephalopathy including a matched control group without encephalopathy. Each neonate received one to three serial Doppler recordings starting at six to 24 hours of life. Mean RI ≤ 0.55 was considered abnormal.

RESULTS

Mean RIs obtained shortly after birth were significantly lower with increasing severity of encephalopathy. On the first Doppler recordings, abnormal mean RIs were seen in 11 of 18 (61%) neonates with mild, 13 of 17 (76%) with moderate, and two of two (100%) with severe HIE. Of the neonates with mild HIE and abnormal mean RIs, congruity abnormal amplitude electroencephalography (45%), brain magnetic resonance imaging (45%), and abnormal head ultrasound (44%) are here reported.

CONCLUSIONS

Doppler measurements can provide bedside adjunct biomarkers indicating the time and severity of neonatal HIE.

Utility of Doppler ultrasound in early-onset neonatal sepsis

Background:

Neonatal sepsis is an important cause of morbidity and mortality among newborns. As there is paucity of literature regarding early alteration of the cerebral blood flow (CBF) in neonatal sepsis our study aims to evaluate the changes in the CBF velocities and Doppler indices in neonates with early-onset neonatal sepsis (EONS) and to evaluate the predictive accuracy of cerebral blood flow velocities (CBFV) by using ultrasound Doppler as a diagnostic marker of EONS.

Methods:

This cross-sectional analytical study was conducted over a period of 2 years with 123 neonates enrolled in the study. The neonates were divided into two groups: Group I (with 54 neonates) - neonates with EONS and group II (with 69 neonates) - age-matched neonates without any signs of sepsis. Ultrasound Doppler examination was performed and the cerebral hemodynamics assessed in neonates during the first seventy two hours of life. Doppler indices and CBFV were measured in the internal carotid artery (ICA), middle cerebral artery (MCA), and vertebral artery (VA) of either side. Data were analyzed using the statistical program SPSS version 23.0 (SPSS Inc., Chicago, IL, USA). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were calculated at different selected cutoff values for CBFV parameters.

Results:

Lower resistance and higher peak systolic velocity and end diastolic velocity have been documented in neonates with EONS.

Conclusion:

Our study shows that the cerebral hemodynamics in neonates with EONS is altered which can be assessed bedside by noninvasive ultrasound Doppler examination.

Cerebral blood flow velocities and cerebrovascular resistance in normal-term neonates in the first 72 hours

AIM

To determine the range of cerebral blood flow velocities (CBFVs) and Doppler indices of cerebrovascular resistance in normal-term neonates as a baseline for a study of hypoxic-ischaemic encephalopathy.

METHODS

The CBFVs, resistive index (RI) and pulsatility index (PI) were measured in the anterior and middle cerebral arteries (ACA and MCA) of 38 normal neonates.

RESULTS

The mean peak systolic, end diastolic and time-averaged velocities (PSV, EDV and TAV) were 36.3 ± 6.6, 12.4 ± 3.9 and 22.0 ± 4.0 cm/s (ACA) and 41.4 ± 13.2, 13.0 ± 5.5 and 25.8 ± 7.9 cm/s (MCA), respectively. All CBFVs in the ACA correlated with gestation; only EDV was correlated to post-natal age. The RI in the ACA (0.67 ± 0.06) and MCA (0.68 ± 0.07) were correlated (r = 0.72, P < 0.001); RI correlated to post-natal age. Two infants with RI < 0.55 were both fed within 25 mins of the study; RI correlated with post-prandial time (dichotomous, pivot 25 min). The mean PI was 1.11 ± 0.18 (ACA) and 1.17 ± 0.23 (MCA). Correlations were observed with post-natal age and post-prandial time (dichotomous). The average angle of insonation was greater in the ACA than in the MCA (median of 5° vs. 18°).

CONCLUSIONS

Results corresponded with previous published studies. No correlation was observed between Doppler indices and gestation as component velocities all increase with advancing gestation. Less variation and smaller standard deviation of CBFV's was associated with a smaller angle of insonation. Low RIs (<0.55), without a pathological cause, warrants further study.

Comparison of Umbilical Cord Milking and Delayed Cord Clamping on Cerebral Blood Flow in Term Neonates

OBJECTIVE

To compare the effect of umbilical cord milking (UCM) and delayed cord clamping (DCC) on cerebral blood flow in term neonates.

METHODS

This randomized controlled trial was conducted at a teaching hospital in India during 2012 to 2013. Two hundred newborns (>36wk) were randomized to UCM and DCC groups. UCM was done on 25cm of cord length. In DCC group, clamping was delayed by 60 to 90s. Resistive Index (RI), Pulsatility Index (PI) and cerebral blood flow velocities of middle cerebral artery (MCA) were measured at 24 to 48h of life.

RESULTS

Baseline characteristics and hemodynamic parameters were comparable. Mean PI [1.18 (0.26)] and RI [0.65 (0.08)] in UCM group was comparable to mean PI [1.18 (0.25)] and RI [0.65 (0.08)] in DCC group. The peak systolic velocity and end diastolic velocity (cm/s) of blood flow in MCA for UCM group were 34.94 (11.82) and 11.71 (4.75) respectively, while in DCC group they were 37.24 (12.63) and 13.07 (4.78) (p 0.23 and 0.07) respectively. Indices among growth retarded babies were not different.

CONCLUSIONS

DCC and UCM had similar effect on cerebral blood flow velocities and Doppler indices in MCA, in term neonates.

Relationship of neonatal cerebral blood flow velocity asymmetry with early motor, cognitive and language development in term infants

The objective of this study was to examine the relationships of Doppler cerebral blood flow velocity (CBFV) asymmetry measures with developmental outcomes in term infants. Doppler CBFV parameters (peak systolic velocity [PSV] and mean velocity [MV]) of the bilateral middle cerebral arteries of 52 healthy term infants were prospectively examined on postnatal days 1-5, and then their motor, cognitive and language development was evaluated with the Bayley Scales of Infant and Toddler Development, Third Edition, at 6, 12, 18 and 24 months of age. The left CBFV asymmetry measure (PSV or MV) was calculated by subtracting the right-side value from the left-side value. Left CBFV asymmetry measures were significantly positively related to motor scores at 6 (r = 0.3-0.32, p < 0.05) and 12 (r = 0.35, p < 0.05) months of age, but were not related to cognitive or language outcome. Thus, the leftward hemodynamic status of the middle cerebral arteries, as measured by cranial Doppler ultrasound in the neonatal period, predicts early motor outcome in term infants.

Is there any influence of breastfeeding on the cerebral blood flow? A review of 256 healthy newborns

OBJECTIVE: To investigate whether breastfeeding influence the cerebral blood-flow velocity. MATERIALS AND METHODS: The present study included 256 healthy term neonates, all of them with appropriate weight for gestational age, 50.8% being female. Pulsatility index, resistance index and mean velocity were measured during breastfeeding or resting in the anterior cerebral artery, in the left middle cerebral artery, and in the right middle cerebral artery of the neonates between their first 10 and 48 hours of life. The data were analyzed by means of a paired t-test, Brieger's f-test for analysis of variance and linear regression, with p < 0.01 being accepted as statistically significant. RESULTS: Mean resistance index decreased as the mean velocity increased significantly during breastfeeding. Pulsatility index values decreased as much as the resistance index, but in the right middle cerebral artery it was not statistically significant. CONCLUSION: Breastfeeding influences the cerebral blood flow velocities.