European Journal of Cardiovascular Medicine

A significant factor in neonatal mortality and morbidity is birth asphyxia. Signs of asphyxia are linked to about 23% of the 4 million new born fatalities and 8% of all deaths worldwide that occur in children under the age of 5 each year.[1]. In fact, 53–61% of new borns diagnosed with moderate to severe hypoxic-ischemic encephalopathy at referral centers in wealthy nations die or suffer from moderate to severe impairment. [2] Fetal hypoxia, hypercarbia, and acidosis are the results of impaired gas exchange between the fetus and placenta during asphyxia. Thereafter, there is a noticeable redirection of blood flow, with less blood going to the kidneys, intestines, and skin and more blood going to the heart, brain, and adrenal glands. In fact, it has been noted that 50–60% of new borns with severe prenatal hypoxia experience multiple organ failure. If this process continues long enough, aberrant cerebral autoregulation and systemic hypotension combine to reduce cerebral blood flow, resulting in cerebral hypoperfusion and hypoxic ischemic damage. [3]

The key tool used to determine the prognosis and possible outcomes of this ischemic state, particularly in preterm new borns, is ultrasonography data, of which the stage of encephalopathy is a critical sign. Mild encephalopathy instances typically include intact neurons with ischemia that mostly affects the periventricular white matter, sometimes resulting in damage to the thalamus and basal ganglia. It has generally been challenging to anticipate the outcome in cases with mild encephalopathy.

Of course, there are many imaging modalities accessible today; to name a few, there is MRI, CT scanning, and ultrasound. Naturally, USG scanning has a number of benefits. It is inexpensive, straightforward, and provides real-time imaging without radiation exposure. As such, it is an ideal choice in situations when it may be necessary to perform repeated scans in order to track the ischemia's progression. It can be completed in the ward itself and doesn't involve any sedation.

SAMPLE SIZE: 50

STUDY DESIGN: Prospective study

STUDY AREA: Burdwan Medical College & Hospital

PERIOD OF STUDY: From 1st MAY 2021 to 31st JULY 2022.

INCLUSION CRITERIA:

1. Both sexes.
2. Age >=12hours and <= 3 days.
3. Clinically diagnosed to have birth asphyxia

EXCLUSION CRITERIA:

1. Neonates with congenital malformations.
2. Neonates with history of intra uterine infections.
3. Neonates with asphyxia due to cardiopulmonary causes.
4. Neonates whose parents/guardian do not give valid informed consent.

Table 1: Distribution of Whether First Breath Required Stimulation

Table 2: Distribution of Birth Complications

Table 3: Distribution of Presence of Reflex

Table 4: Distribution of Clinical Outcome in the Study Population

In our study, 44 (88.0%) patients had Required Stimulation for First Breath. The value of z is 7.6. The value of p is < .00001. The result is significant at p < .05. In our study, 38 (76.0%) patients had Presence of Birth Complication. The value of z is 5.2. The value of p is < .00001. The result is significant at p < .05. In our study, 43 (86.0%) patients had Presence of Birth Complication. The value of z is 7.2. The value of p is < .00001. The result is significant at p < .05. In our study, 2 (4.0%) patients Clinical Outcome were Death, 7 (14.0%) patients Clinical Outcome Clinical were Mild 15 (30.0%) patients Clinical Outcome were i Moderate, 21 (42.0%) patients Clinical Outcome were Normal and 5 (10.0%) patients Clinical Outcome where patients Clinical Outcome were Severe. The value of z is 4.5149. The value of p is < .00001. The result is significant at p < .05.

Guilherme S. Cassia et al found that colour Doppler brain imaging can yield accurate and thorough information about newborns that have asphyxia. [4]. As a result, numerous attempts have been made to extract data from brain doppler research. The Resistive Index is one of these variables.

The doppler resistive index has been employed as a measure to assess the efficacy of transfusion because, in the event of a significant diastolic velocity decline, the index approaches 1, resulting in a situation in which blood transfusion effectively only takes place at the peak systolic velocity. When the peak systolic velocity itself significantly drops, it also approaches 1, rendering transfusion useless once more. Thus, this characteristic can be utilized to forecast the potential for imminent ischaemia.

The results of this study indicate that there is a strong correlation between the resistive indices for every baby examined. This suggests that there is a high frequency of insults closer to the origin of the anterior cerebral artery and the middle cerebral artery. Furthermore, as the arteries come from the "Circle of Willis," contralateral injury should be anticipated because it's possible that some contributory artery, such the Internal Carotid Arteries, is where the hypoxic ischemic insult originates.

In many clinical circumstances, the resistive index has been employed as a stand-in to monitor for healthy tissue perfusion because of its strong correlation with the vessel's flow. In particular, renal artery resistive indices have been extensively studied for their potential to predict renal tissue perfusion in conditions like chronic renal disease or in the acute setting of pre-renal acute kidney disease. However, clinical application of these indices has proven challenging thus far, possibly as a result of a lack of deeper understanding of flow dynamics and the physiology of the renal vasculature. Only a small number of highly mentioned studies examine this topic in particular in relation to hypoxic-ischemic injuries in the newborn age range. One of these, by B Guan et al. [5] looked at nearly 158 neonates, it is more than three times the sample size obtained here, and it was shown that almost all of them had abnormal cerebral arterial blood flow velocity and resistive indices.

It's interesting to note that the data do not, in fact, point to a straight-line correlation between the clinical result and the cerebral artery resistive index values. In order to examine this in the context of the current study, the clinical outcomes were transcoded to an integer scale using a numerical code. Values on the scale ranged from 1 to 5, with 5 representing "Death" and 1 representing "Normal”. Curiously, though, the scatter plot showed that RI values clustered around each event, even if the order of the outcomes did not directly change as RI values increased. Upon examining the data graphs, it appeared reasonable that the transcoding of "Normal" to 2 from 1—thus replacing the original meaning of 1 as "Mild"—would result in a nearly direct correlation with RI levels.

This suggests that whereas hypoxic-ischemic states and outcomes are associated with high RI values, low values should also be avoided. Low RI values indicate a decreasing difference between the systolic and diastolic values. It is hypothesized that this decreasing change in velocity can be attributed to a state where the pressure remains constant, or that the pulse pressure is null. This is a significant indicator of a poor prognosis for the baby's cardiac state because it increases the likelihood of decreased perfusion, which raises the possibility of a worse clinical outcome.

A similar scenario was reported by Lou et al When it is stated that cerebral blood flow in asphyxiated babies becomes pressure passive, meaning that perfusion decreases with hypotension and increases sharply with a little increase in blood pressure.[6] This lack of autoregulation is seen more commonly in premature infants. Another study by Pearlman et al established a significant relationship between fluctuation of cerebral blood flow velocity in neonates with respiratory distress syndrome [7]. One noteworthy finding in the data is that there were only two instances of "Death" in the sample, and in both occasions, there was a 100% incidence of not exhibiting any typical reflexes, such as the Moro's reflex or finger grabbing. It is evident that the absence of these reflexes is a poor prognosis factor, but it's intriguing to note how this relates to the results of another study. by Narayan S, et al. [8] who observed a strong correlation between neuromotor result and ultrasonographic resistive indices. Taking into account the inclusion criteria of asphyxiated births, it can be observed that the mean resistive index values for the ACA and MCA, respectively, are both over 0.7, but also correlates to the finding of Jain H et al. [9] who showed that resistive index values were lower in cerebral vessels in asphyxiated neonates on the first and third days of life. The question of what resistive index values are appropriate baseline values has now generated a great deal of discussion and debate in the literature. Normal developmental processes in the infant have an impact on the cerebral circulation's arterial hemodynamics. In full-term babies, the resistive index (RI) in the anterior cerebral artery decreases to 0.7 (range 0.6 to 8) from a mean of 0.78 (range 0.5 to 1) in preterm infants. This is further supported by the current study's results, which showed extremely similar mean values for the middle cerebral artery and anterior cerebral artery resistive indices. While the range of published normal values is wide, there shouldn't be a lot of variation within a single subject. Any deviation from baseline readings of greater than 50% ought to be regarded as abnormal. It may be possible to understand the phenomenon underlying the single outlier instance by taking into account this paradigm shift, which states that values differing from a baby's own normal baseline are more significant than values differing from an average baseline determined from the research population: Situation 9 The pattern in the remaining data seems to be broken by case number 9. The absence of reflexes upon examination is one of the case's intriguing features, which it shares with previous cases that ended in death. Furthermore, it is possible that the infant had lower baseline readings from the beginning. It's also feasible that the outlier example represents a more severe pathophysiological pathway linked to lower RI values, as was previously discussed. In this case, the lower RI value is merely a step in an unrecorded decline that occurred before cardiac output was too low. It follows that attempts to use the resistive indices to directly estimate the patient's prognosis may be complicated by the possibility that these parameters are additional determining factors about the case's prognosis. To rule this out and see precisely how these elements affect the case's outcome, more research with a bigger sample size is necessary. This may be related to the results of a study conducted by Liv, Cav, and Huang96, which indicates that patients who are severely asphyxiated may have a considerably raised (RI 81 >0.90) or strongly lowered (RI>0.90) or markedly decreased (RI<0.01) resistive index.

Based on this study, the conclusion that may be arrived at is:

1. It has been demonstrated that ultrasonography can be used to evaluate a newborn who has asphyxia..
2. The clinical outcome of a neonate receiving hypoxic-ischemic insults is positively connected with the resistant indices of the middle cerebral artery and anterior cerebral artery.
3. Bad clinical outcomes are associated with both extremely high and low RI values.
4. Every instance where the clinical outcome was death had no neuromotor reflexes..
5. 10% of cases had a severe clinical outcome, indicating that in order to address the poor prognosis, treatment needs to be improved.
6. An anomalous instance was noted, indicating that additional research into the impact of additional potential contributors, such as the existence of reflexes, was necessary..
7. To fully comprehend the pathophysiology of hypoxic-ischemic injury, more research is necessary.

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