Cerebral oxygenation monitoring in critically congenital heart neonates during cardiac catheterization

Introduction

Cerebral Oximetry:

NIRS and cerebral oximetry are only two terms for the same technology. The reason they rely on it is that oxyhemoglobin, deoxyhemoglobin, and cytochrome aa3 all have distinct absorption patterns in the 700 to 900 nm region of near infrared light, and biological tissue is rather transparent to this light. The redox status of cytochrome aa3, amounts of oxy- and deoxyhemoglobin, and ScO₂ can be determined by analysing light signals at many wavelengths ^[1].

At this time, the gadgets use either frequency-domain or continuous-wave technology. The intensity of the detected light in relation to the emitted light is measured by continuous wave devices, which have been available for sale for some time. These devices monitor changes in oxygenation levels over time, beginning with an unknown initial value^[2].

One new technology that can measure the phase-shift and intensity of detected light relative to emitted light is frequency-domain

devices. These gadgets can find the initial oxygenation level and track its evolution over time ^[3].

There are clear distinctions between pulse-oximetry and cerebral oximetry. Cerebral oximetry measures the non-pulsatile signal component that represents the circulation of tissues, such as arterioles, capillaries, and venules, in contrast to pulse oximetry, which measures the pulsatile signal component that represents the arterial circulation. Around 85% of the signal from venules contributes to the cerebral oximetry "weighted average" of blood flow in brain tissue. Subtracting the amount of ScO₂ from SaO₂ yields the estimated cerebral oxygen extraction (CEO₂), since ScO₂ is a good approximation of venous SO₂. Brain oximetry shows a banana-shaped amount of tissue around 2 cm below the optical probe ^[1].

A sensor is placed on the skin across the temporal and frontal lobes of the brain in this noninvasive method. This method involves penetrating the brain with a low-intensity near-infrared light beam in order to detect changes in tissue chromophores like haemoglobin ^[4].

The spectral absorption of oxygenated and deoxygenated haemoglobin in the brain can be determined by detecting light at two distinct distances from its source. Analysing the data is as simple as comparing the relative changes over time. The result is shown as an oxygen saturation index (rS02) of the cerebral cortex's combined arterial and venous blood ^[5].

Nearly 70% of the signal originates in the venous compartment, 20% in capillaries, and 10% in arterioles ^[6].

Aim of the work

The goal is to assess brain oxygenation in cases of severe congenital heart defects undergoing cardiac catheterization using near-infrared spectroscopy (NIRS).

Reduced brain injury, including alterations in neurocognitive function and blood biomarkers, is a result of using NIRS cerebral oximetry. Transfusion rates, mortality, and resource utilisation are all decreased, and injuries to

other organs, such as the brain and heart, are also decreased.

Patients and methods

The catheterization laboratory of the paediatric cardiology section at Cairo University Hospital was the site of. beginning on November 1, 2021, and continuing until November 30, 2023, the research will be conducted.

Fifty individuals in direct  need of an invasive cardiac catheterization due to critical congenital heart disease were enrolled in this trial.

Patients : ( Cases & Controls)

Since every patient admitted to the cardiac catheterization unit at Abo El Resh Medical Center's tertiary cardiac and newborn intensive care unit (NICU) had a record from the time of admission until their discharge, we rely on their (Registration) sector.

Five categories were established from the study population based on the results of the echocardiography:

Class 1: TGA (Great Arteries Transposition)

Class 2: Duct-dependent systemic circulation; Coarctation of the aorta (CoA) with ventricular septal defect (VSD), interrupted aortic arch (IAA) with VSD, and functional single ventricle (FSV) with CoA)

As a third group, we have duct-dependent pulmonary circulation, tetralogy of fallot with pulmonary atresia (PA) or pulmonary stenosis (PS), and FSV with PA or PS.

Class 4: Ebstein abnormality, tricuspid dysplasia, and regurgitation lesions

Class 5: Combination lesion, truncus arteriosus, and total abnormal pulmonary venous return ("TAPVR"). In 2018, Merck was based in Kenilworth, New Jersey.

Inclusion criteria for the patients:

1) All youngsters hospitalized to the Abo El Resh medical center had serious congenital heart disease.

2)  1–90 days of age

3) Received admission between November 2021 and November 2023.  Operated on both Saturday and Tuesday.

4) Echocardiography confirmed the diagnosis of critical congenital heart disease.

5) The parent's legal approval and written authorization

Exclusion criteria for the patients:

1-Hemorrhagic Ischemic Cerebrovascular Disease          

Two, abnormalities of the central nervous system that occur during birth

3- Kernicterus  

4- Illnesses related to biochemistry (Neurometabolic disorders)

5- Disorders affecting brain development                

6- Seizures in  patients

Discussion

A critical congenital heart defect is one that is obvious at birth and requires medical attention within a year of life due to structural abnormalities in the heart. Out of all the newborn deaths due by birth defects, congenital heart disease makes up 30-50%. There were more than 13,000 infant fatalities in the US attributable to congenital heart defects between 1999 and 2006, prior to the implementation of essential congenital heart disease newborn screening ^[7].

Any form of congenital heart defect (CHD) requiring medical intervention within the first year of a person's life is considered serious, according to the American Heart Association (AHA). The more realistic way to put it is that it's Congenital Heart Disease (CHD) if it required medical treatment or caused death within the first 28 days of life. Eckersley et al., (2016) used this categorization to choose the forms of congenital heart disease (CHD) that may benefit from a screening module used in the early stages ^[8].

Patients with coronary heart disease are at increased risk for brain damage during and after cardiac treatments such as catheterization or surgery. Cognitive abilities, physical skills, social interaction, behaviour, language, focus, and executive function are just few of the areas that might be impacted by neurodevelopmental disability.^[9] is a reference to a study that was carried out by Kim and colleagues in the year 2021. ^[10] is about a study that was carried out by Zhu and colleagues in the year 2020.

In the catheterization lab of the pediatric cardiology division at Cairo University Hospital, researchers carried out a prospective observational cohort study. The research will run from November 1, 2021, to November 30, 2023. Fifty infants and newborns in serious need of invasive cardiac catheterization due to congenital heart defects were enrolled in this study ^[15].

With an emphasis on the advantages of INVOS and an assessment of the immediate prognosis within 6 months after the procedure, this prospective study sought to examine the short-term fate of critically sick babies undergoing cardiac catheterization.

Fifty people took part in the study. Fifty neonates who needed an invasive cardiac catheterization immediately due to a serious congenital heart defect were the subjects of the study. The procedures were conducted on Saturdays and Tuesdays during the study period, which lasted from November 2021 to November 2023. Fifty instances served as a control group that did not receive INVOS monitoring; these patients were compared to them. In the perspective of just one center experience, this amount is substantial, particularly when contrasted with others^[16].

Echocardiography diagnoses were used to classify the study population into five groups.

First category: TGA, or transposition of the main arteries.

Condition such as functional single ventricle (FSV) with coarctation of the aorta (CoA) or interrupted aortic arch (IAA) with ventricular septal defect (VSD) is part of Group 2, which includes situations where the duct is dependent on the systemic circulation.^[17]

Group 3 includes situations where the pulmonary circulation is dependent on a duct, such as tetralogy of Fallot (TOF) with pulmonary atresia (PA) or pulmonary stenosis (PS), or functional single ventricle (FSV) with PA or PS^[18].

Regurgitation lesions, tricuspid dysplasia, and Ebstein's abnormalities are all part of Group 4.

The fifth category includes lesions that cause blood to mix, such as truncus arteriosus and total anomalous pulmonary venous return, or TAPVR. The 2018 Merck headquarters are in Kenilworth, New Jersey^[20].

Both NIRS and cerebral oximetry mean the same thing. The absorption spectra of oxyhemoglobin, deoxyhemoglobin, and cytochrome aa3 are different, and their reliance on the relative transparency of biological tissue to near-infrared light (700-900 nm) is crucial. Various light signals at different wavelengths can be used to evaluate cytochrome aa3 redox status, oxy-and deoxyhemoglobin levels, and ScO₂ concentrations ^[11].

At this time, the devices use either continuous-wave or frequency-domain technology. Because they compare the amount of light that is detected to the amount of light that is emitted, continuous wave devices have been available for a while. Over time, relative to an unknown initial point, the authors ^[12] show variations in oxygenation levels.

Cerebral oximetry and pulse-oximetry differ in a number of important ways. The use of near-infrared light signals is common in both cerebral oximetry and pulse oximetry. The non-pulsatile signal component, which indicates circulation in tissues including venules, capillaries, and arterials, is especially monitored by cerebral oximetry. Conversely, pulse oximetry measures arterial blood flow by monitoring the pulsatile signal component. A "weighted average" of tissue circulation is produced by cerebral oximetry, which shows that 85% of the signal comes from venules. Since ScO₂ is similar to venous SO₂, the difference between SaO₂ and ScO₂ (CEO₂ 5 SaO₂ 2 ScO₂) can be used as a sign of cerebral O₂ extraction (CEO₂). Using cerebral oximetry, a banana-shaped tissue compartment with a diameter of about 2 cm is illuminated ^[13].