Clinical value of color Doppler ultrasonography measurements of full-term newborns with perinatal asphyxia and hypoxic ischemic encephalopathy in the first 12 hours of life and long-term prognosis

Multidisciplinary rehabilitation intervention on mobility and hemodynamics of joint contracture animal model

BACKGROUND

Joint contracture causes a decrease in range of motion (ROM), which severely affects activities of daily living of patients. We have investigated the effectiveness of a multidisciplinary rehabilitation on joint contracture by rat model.

METHODS

We used 60 Wistar rats in this study. The rats were divided into five groups as follows: group 1 was the normal control group; except the group 1, we created left hind limb knee joint contracture using Nagai method for other four groups. The joint contracture modeling group 2 was the model control group for monitoring the spontaneous recovery, and other three groups were given different rehabilitation treatments; for example, group 3 was treadmill running group; group 4 was medication group; group 5 was treadmill running plus medication group. The left hind limbs knee joint ROM and the femoral blood flow indicators (FBFI) including PS, ED, RI, and PI were measured right before and after the 4 weeks of rehabilitation.

RESULT

After 4 weeks of rehabilitation treatments, the measured values of ROM and FBFI are compared with the corresponding values of group 2. Firstly, we did not see clear difference in the values of ROM and FBFI for group 2 before and after 4 weeks spontaneous recovery. The improvement of left lower limb ROM for group 4 and group 5 as compared to the group 2 was statistically significant (p < 0.05), whereas a less recovery for group 3 was observed. However as compared to the group 1, we did not observe full recovery in ROM of group 4 and group 5 after 4 weeks of rehabilitation. The PS and ED level for rehabilitation treatment groups was significantly higher than those modeling ones (Tables 2, 3,  Figs. 4, 5), while the RI and PI values show the contrary trends (Tables 4, 5, Figs. 6, 7).

CONCLUSION

Our results indicate that multidisciplinary rehabilitation treatments had a curative effect on both contracture of joints and the abnormal femoral circulations.

A Scoping Review of Cerebral Doppler Arterial Waveforms in Infants

Cerebral Doppler ultrasound has been an important tool in pediatric diagnostics and prognostics for decades. Although the Doppler spectrum can provide detailed information on cerebral perfusion, the measured spectrum is often reduced to simple numerical parameters. To help pediatric clinicians recognize the visual characteristics of disease-associated Doppler spectra and identify possible areas for future research, a scoping review of primary studies on cerebral Doppler arterial waveforms in infants was performed. A systematic search in three online bibliographic databases yielded 4898 unique records. Among these, 179 studies included cerebral Doppler spectra for at least five infants below 1 y of age. The studies describe variations in the cerebral waveforms related to physiological changes (43%), pathology (62%) and medical interventions (40%). Characteristics were typically reported as resistance index (64%), peak systolic velocity (43%) or end-diastolic velocity (39%). Most studies focused on the anterior (59%) and middle (42%) cerebral arteries. Our review highlights the need for a more standardized terminology to describe cerebral velocity waveforms and for precise definitions of Doppler parameters. We provide a list of reporting variables that may facilitate unambiguous reports. Future studies may gain from combining multiple Doppler parameters to use more of the information encoded in the Doppler spectrum, investigating the full spectrum itself and using the possibilities for long-term monitoring with Doppler ultrasound.

Does abnormal Doppler on cranial ultrasound predict disability in infants with hypoxic-ischaemic encephalopathy? A systematic review

AIM

To evaluate whether abnormal resistive index or cerebral blood flow velocity (CBFV) on cranial ultrasound predicts disability (≥1 year) in infants with hypoxic-ischaemic encephalopathy (HIE).

METHOD

This was a systematic review and meta-analysis of studies comparing developmental outcomes of infants with HIE with normal versus abnormal resistive index or CBFV.

RESULTS

Twenty-six studies were included (pre-therapeutic hypothermia era, 20; therapeutic hypothermia era, six). Data from 15 studies (pre-therapeutic hypothermia, 10; therapeutic hypothermia, five) were available for meta-analysis. Pooled sensitivity and specificity, summary area under the receiver operating characteristic curve, and diagnostic odds ratio of resistive index or CBFV for predicting 'death or severe disability' were as follows. Pre-therapeutic hypothermia era: 0.83 (95% confidence interval [CI] 0.45-0.97) and 0.92 (95% CI 0.74-0.98), 0.94 (95% CI 0.92-0.96), 54 (95% CI 7-391). Therapeutic hypothermia era (measurements before therapeutic hypothermia): 0.62 (95% CI 0.41-0.80) and 0.96 (95% CI 0.88-0.99), 0.93 (95% CI 0.89-0.94), 23 (95% CI 6-91). Therapeutic hypothermia era (measurements during/after therapeutic hypothermia): 0.51 (95% CI 0.24-0.78) and 0.83 (95% CI 0.73-0.90), 0.81 (95% CI 0.78-0.85), 5 (95% CI 2-13). Overall Grading of Recommendations Assessment, Development and Evaluation (GRADE) rating of evidence was 'low' or 'very low'.

INTERPRETATION

Low-level evidence suggests that abnormal resistive index or CBFV can predict death or disability with high sensitivity and specificity in infants with HIE who are not cooled. The specificity of these tests was high when performed before starting cooling in infants who received therapeutic hypothermia.

WHAT THIS PAPER ADDS

Cerebral doppler ultrasound may be useful in predicting death or disability in infants with hypoxic-ischaemic encephalopathy who are not cooled. Cerebral doppler ultrasound may also be useful in infants who are cooled, if done before starting cooling. Cerebral doppler ultrasound may not be useful when performed during or after completing cooling.

Using Doppler sonography resistive index for the diagnosis of perinatal asphyxia: a multi-centered study

Background and objective

Inhere we evaluated the diagnostic utility of Doppler sonography (DS) of the anterior cerebral artery (ACA), middle cerebral artery (MCA) and the basilar arteries (BA) based on resistive index (RI) for the diagnosis of asphyxia.

Methods

In this multi-centered cross-sectional study, neonates with clinical diagnosis of asphyxia, were considered for study. During the first 24 h, neonates underwent DS. MRI was done for each neonate during the first month, after discharge or during hospital admission, after obtaining clinical stability. Staging based on DS was compared with staging based on MRI.

Results

Overall, 34 patients entered the study. DS of the ACA, MCA, BA all had significant correlation with MRI findings (regarding severity of asphyxia) (r > 0.8 and p < 0.001).

In the receiver-operating-characteristic analysis, ideal cut-off point for diagnoses of asphyxia based on ACA and BA was RI ≤ 0.62 [area under the curve (AUC) = 0.957 and 95% CI: 0.819–0.997; sensitivity = 95.65; specificity = 100; positive predictive value (PPV) = 100; negative predictive value (NPV) = 90.9 and negative likelihood ratio (NLR) = 0.043]. Regarding MCA, similarly, a RI ≤ 0.62 was ideal for differentiating between normal and asphyxiated neonates (AUC = 0.990 and 95% CI: 0.873–1; sensitivity = 91.30; specificity = 100; PPV = 91.2; NPV = 100 and NLR = 0.087).

Conclusion

For evaluating neonates clinically suspected of asphyxia, especially in centers with limited facilities such as MRI, DS can be used as a first line diagnostic modality and RI of ≤ 0.62 is an appropriate cut-off for the diagnosis of perinatal asphyxia.

Early postnatal color Doppler changes in neonates receiving delivery room resuscitation with low 5 min Apgar score-a pilot study

AIMS AND OBJECTIVES

To evaluate the Doppler changes in the intracranial arteries of neonates exposed to perinatal hypoxic insult and compare it with normal neonates.

MATERIALS AND METHODS

Color Doppler of bilateral anterior and middle cerebral arteries was performed within 6 h of birth in 26 healthy neonates and 50 neonates who received delivery room resuscitation (DRR) for perinatal depression and had a 5 min Apgar score <7. Comparisons of resistive index (RI) and peak systolic velocity (PSV) were made between the (a) control group (b) patients with low 5 min Apgar score <7 who without clinical features of neonatal encephalopathy at 24 h (c) neonates with perinatal depression with a clinical evidence of disturbed neurological function at 24 h of birth and examination consistent with mild, moderate, or severe encephalopathy using modified Sarnat and Sarnat's classification.

RESULTS

Significantly higher RI was observed in the neonates with to perinatal depression compared to the normal neonates. Significantly higher RI was seen in the patients with clinical features of neonatal encephalopathy (Group C) compared to group B. RI <0.6 and >0.82 was associated with severe neonatal encephalopathy. Differences in PSV were not statistically significant in the various groups.

CONCLUSION

The study presents the changes in early cerebral Doppler parameters observed in neonates with low 5 min Apgar score following DRR compared to the normal neonates. We also present the relations of Doppler parameters with increasing severity of neonatal encephalopathy according to Sarnat classification.

Hemodynamic instability associated with increased risk of death or brain injury in neonates with hypoxic ischemic encephalopathy

OBJECTIVE

To determine the association between hemodynamic instability requiring inotropes and brain injury or death in neonates with hypoxic ischemic encephalopathy (HIE).

METHODS

Retrospective cohort study of 221 neonates with HIE. Brain injury was defined using four HIE patterns based on MRI diffusion or T1 changes. The primary outcome was death or brain injury. Secondary outcomes were abnormal MRI, death, and abnormal EEG. Logistic regression was used to examine the risk of death or brain injury with the use of inotropes while adjusting for confounding factors.

RESULTS

Brain injury or death occurred more often in neonates who received inotropes (71.1%, 69/97) compared to those who did not (44.3%, 55/124). The use of inotropes was associated with increased risk of death or brain injury (OR 3.11; 95% CI 1.39-7.004) and abnormal MRI (OR 2.78; 95% CI 1.22-6.34) after adjusting for confounding factors. Mortality was significantly higher in neonates exposed to inotropes (21.6%, 21/97) compared with those who did not receive inotropes (4%, 5/124), P < 0.001.

CONCLUSION

In infants with HIE, hemodynamic instability requiring inotropes in the first 72 hours of life was associated with increased risk of death or brain injury detected by MRI.

Early diagnosis and outcome prediction of neonatal hypoxic-ischemic encephalopathy with color Doppler ultrasound

PURPOSE

To describe the ultrasound presentation of the brain and cerebral hemodynamics in neonates with hypoxic-ischemic encephalopathy (HIE) by comparison with control subjects.

MATERIAL AND METHODS

During June 2012 to April 2013, full term neonates who had clinical evidence of HIE were enrolled. Healthy newborns without HIE were used as a control group. Cerebral parenchyma, size of lateral ventricles and hemodynamic parameters of cerebral arteries were studied using two-dimensional duplex and color Doppler ultrasound. Neonates with moderate and severe HIE were followed-up with ultrasound for at least 3 months.

RESULTS

A total of 158 consecutive neonates (82 boys and 76 girls), including 54 with mild HIE, 60 with moderate HIE and 44 with severe HIE were included. One hundred and twenty healthy newborns were randomly selected as a control group. Abnormal ultrasound findings of brain parenchyma were found in 25/54 (46.3%) neonates with mild HIE whereas they were found in 58/60 (96.7%) neonates with moderate HIE and 44/44 (100%) neonates with severe HIE. Almost all neonates with severe HIE had decreased cerebral artery blood flow velocity and increased resistance index of cerebral arteries. Of the 104 neonates with moderate or severe HIE, follow-up ultrasound examination revealed cystic parenchymal lesions in 12/104 (11.5%), progressive ventricular dilatation and brain atrophy in 12/104 (11.5%), mild ventricular dilatation in 15/104 (14.4%) and leukoencephalomalacia in 2/104 (1.9%) neonates.

CONCLUSION

Ultrasound features such as the size of lateral ventricles, altered brain parenchymal echogenicity and cerebral blood flow parameters are useful for the early diagnosis of HIE and help predict outcome.

Rodent Hypoxia-Ischemia Models for Cerebral Palsy Research: A Systematic Review

Cerebral palsy (CP) is a complex multifactorial disorder, affecting approximately 2.5-3/1000 live term births, and up to 22/1000 prematurely born babies. CP results from injury to the developing brain incurred before, during, or after birth. The most common form of this condition, spastic CP, is primarily associated with injury to the cerebral cortex and subcortical white matter as well as the deep gray matter. The major etiological factors of spastic CP are hypoxia/ischemia (HI), occurring during the last third of pregnancy and around birth age. In addition, inflammation has been found to be an important factor contributing to brain injury, especially in term infants. Other factors, including genetics, are gaining importance. The classic Rice-Vannucci HI model (in which 7-day-old rat pups undergo unilateral ligation of the common carotid artery followed by exposure to 8% oxygen hypoxic air) is a model of neonatal stroke that has greatly contributed to CP research. In this model, brain damage resembles that observed in severe CP cases. This model, and its numerous adaptations, allows one to finely tune the injury parameters to mimic, and therefore study, many of the pathophysiological processes and conditions observed in human patients. Investigators can recreate the HI and inflammation, which cause brain damage and subsequent motor and cognitive deficits. This model further enables the examination of potential approaches to achieve neural repair and regeneration. In the present review, we compare and discuss the advantages, limitations, and the translational value for CP research of HI models of perinatal brain injury.

Cerebral blood flow velocity and neurodevelopmental outcome in infants undergoing surgery for congenital heart disease

BACKGROUND

Cerebral blood flow velocity (CBFV) measured by transcranial Doppler sonography has provided information on cerebral perfusion in patients undergoing infant heart surgery, but no studies have reported a relationship to early postoperative and long-term neurodevelopmental outcomes.

METHODS

CBFV was measured in infants undergoing biventricular repair without aortic arch reconstruction as part of a trial of hemodilution during cardiopulmonary bypass (CPB); CBFV (Vm, mean; Vs, systolic; Vd, end-diastolic) in the middle cerebral artery and change in Vm (rVm) were measured intraoperatively and up to 18 hours post-CPB. Neurodevelopmental outcomes, measured at 1 year of age, included the psychomotor development index (PDI) and mental development index (MDI) of the Bayley Scales of Infant Development-II.

RESULTS

CBFV was measured in 100 infants; 43 with D-transposition of the great arteries, 36 with tetralogy of Fallot, and 21 with ventricular septal defects. Lower Vm, Vs, Vd, and rVm at 18 hours post-CPB were independently related to longer intensive care unit duration of stay (p<0.05). In the 85 patients who returned for neurodevelopmental testing, lower Vm, Vs, Vd, and rVm at 18 hours post-CPB were independently associated with lower PDI (p<0.05) and MDI (p<0.05, except Vs: p=0.06) scores. Higher Vs and rVm at 18 hours post-CPB were independently associated with increased incidence of brain injury on magnetic resonance imaging in 39 patients.

CONCLUSIONS

Postoperative CBFV after biventricular repair is related to early postoperative and neurodevelopmental outcomes at 1 year of age, possibly indicating that low CBFV is a marker of suboptimal postoperative hemodynamics and cerebral perfusion.

Sildenafil mediates blood-flow redistribution and neuroprotection after neonatal hypoxia-ischemia

BACKGROUND AND PURPOSE

The best conceivable treatment for hypoxia-ischemia (HI) is the restoration of blood flow to the hypoxic-ischemic region(s). Our objective was to examine whether boosting NO-cGMP signaling using sildenafil citrate, a phosphodiesterase-type 5 inhibitor, could modify cerebral blood flow and reduce lesions in the developing brain.

METHODS

HI was induced in P7 Sprague-Dawley rats by unilateral carotid artery occlusion and hypoxia, and followed by either PBS or sildenafil. Blood-flow velocities were measured by ultrasound imaging with sequential Doppler recordings to evaluate collateral recruitment. Cell death, blood-brain barrier integrity, and glial activation were analyzed by immunohistochemistry. Motor behavior was evaluated using an open-field device adapted to neonatal animals.

RESULTS

Sildenafil citrate (10 mg/kg) induced collateral patency, reduced terminal dUTP nick-end labeling-positive cells, reactive astrogliosis, and macrophage/microglial activation at 72 hours and 7 days post-HI. Sildenafil also reduced the number of terminal dUTP nick-end labeling-positive endothelial cells within lesion site. Seven days after HI and sildenafil treatment, tissue loss was significantly reduced, and animals recovered motor coordination.

CONCLUSIONS

Our findings strongly indicate that sildenafil citrate treatment, associated with a significant increase in cerebral blood flow, reduces HI damage and improves motor locomotion in neonatal rats. Sildenafil may represent an interesting therapeutic strategy for neonatal neuroprotection.

Cerebral blood flow during reperfusion predicts later brain damage in a mouse and a rat model of neonatal hypoxic-ischemic encephalopathy

Children with severe neonatal hypoxic-ischemic encephalopathy (HIE) die or develop life-long neurological impairments such as cerebral palsy and mental retardation. Decreased regional cerebral blood flow (CBF) is believed to be the predominant factor that determines the level of tissue injury in the immature brain. However, the spatio-temporal profiles of CBF after neonatal HIE are not well understood. CB17 mouse and Wistar rat pups were exposed to a unilateral hypoxic-ischemic (HI) insult at eight or seven days of age. Laser speckle imaging sequentially measured the cortical surface CBF before the hypoxic exposure and until 24h after the hypoxic exposure. Seven days after the HI insult, brain damage was morphologically assessed by measuring the hemispheric volumes and by semi-quantitative scoring for neuropathologic injury. The mean CBF on the ipsilateral hemisphere in mice decreased after carotid artery ligation. After the end of hypoxic insult (i.e., the reperfusion phase), the mean CBF level gradually rose and nearly attained its pre-surgery level by 9h of reperfusion. It then decreased. The degree of reduced CBF during reperfusion was well correlated with the degree of later morphological brain damage. The correlation was the strongest when the CBF was measured in the ischemic core region at 24h of reperfusion in mice (R²=0.89). A similar trend in results was found in rats. These results suggest that the CBF level during reperfusion may be a useful predictive factor for later brain damage in immature mice. This may enable optimizing brain damage for detail analyses.

Ultrasonic assessment of cerebral blood flow changes during ischemia-reperfusion in 7-day-old rats

A model of ischemic brain injury in 7-day-old rat pups has been developed to study perinatal ischemia. It combines permanent occlusion of the distal left middle cerebral artery (LMCA) and transient occlusion of homolateral common carotid artery (LCCA). At removal of the clip on LCCA, reflow allowed brain reperfusion through cortical anastomoses. In 10 rat pups, we measured blood flow velocities (BFV) in main cerebral arteries with 12-MHz ultrasound imaging. At basal states, peak systolic BFV in proximal LMCA was 16.0 +/- 3.0 cm.s(-1). Occlusion of LMCA did not yield significant modifications. Occlusion of LCCA involved only a decrease in BFV to 9.5 +/- 2.6 cm.s(-1) (p < 0.001). Indeed, LMCA was then supply by the right internal carotid and the vertebral arteries through the circle of Willis. In three rat pups, release of occlusion of LCCA was followed by restoration of BFV in the left internal carotid artery and in LMCA, in seven pups, by a reversed flow in the LICA and lower BFV in LMCA (11.9 +/- 2.3, p < 0.05). BFV returned to basal values from h5 to h48 in all animals. In addition, ultrasound imaging is a useful, reproducible, non invasive, easy-to-repeat, method to assess and monitor arterial cerebral blood flow supply in small animals. It helps to characterize changes occurring during cerebral ischemia and reperfusion, particularly the depth of the hypoperfusion, as well as the variability of reflow. In preclinical studies, this method could help to identify what can be assigned to a neuroprotective treatment and what depends on changes in cerebral blood flow supply.

Blood flow velocities in the anterior cerebral artery and basilar artery in asphyxiated infants

OBJECTIVE

The aim of this series was to determine whether cerebral blood flow velocities (CBFVs) in the anterior cerebral artery (ACA) and basilar artery (BA) correlate with the severity of asphyxia in infants and whether these velocity measures can be useful for predicting early developmental prognosis.

METHODS

We measured CBFVs in the ACA and BA by using pulsed Doppler sonography in 29 healthy and 17 asphyxiated infants (11 with mild asphyxia [median gestational age, 38 weeks; median birth weight, 2856 g] and 6 with severe asphyxia [38.5 weeks; 2910 g]).

RESULTS

In the mildly asphyxiated infants, the median diastolic and systolic velocities in the ACA were 10.4 and 32.5 cm/s, respectively, and those in the BA were 10.5 and 33.1 cm/sec. In the severely asphyxiated infants, the median diastolic and systolic velocities in the ACA were 19.8 and 40.5 cm/s, and those in the BA were 30.2 and 60.5 cm/s. The BA:ACA ratios (CBFV in the BA/CBFV in the ACA) in both the diastolic and systolic periods were higher in the severely asphyxiated infants than in the mildly asphyxiated infants (0.94 versus 1.35; P< .01; 1.01 versus 1.38; P< .01).

CONCLUSIONS

These preliminary results suggest that CBFVs in the BA correlate with the degree of neonatal asphyxia and may be useful to predict the neurodevelopmental outcome. We submit that the increased CBFV in the BA may represent the preferential blood flow to the brain stem region.