NEUROTRANSMISORES Y SISTEMAS REALES Los neurotransmisores son sustancias producidas en las

Congenital Diaphragmatic Hernia

• Bochdalek’s Hernia (posterolateral hernia): This is really the persistence of the pleuroperitoneal canal. MC diaphragmatic hernia in children, more common on left side. Classic triad of respiratory distress, apparent dextrocardia and a scaphoid abdomen. Pulmonary hypoplasia is the MC cause of morbidity and mortality.

• Morgagni Hernia (retrosternal anterior hernia): Defect is between the sternal and costal attachments of the diaphragm. Usually occurs on right side, in adults, particularly females. MC involved viscus is the transverse colon.

Ponderal Index (PI) In Neonate

• Ponderal index has been used as an indicator of fetal growth status, especially to assess assymetrical IUGR.

• The Ponderal index is calculated by multiplying the weight in grams by 100 and then dividing it by cube of length in cm.

Ponderal Index = Weight (gm)/Length (cm)³ x100

• A ponderal index below the 10th percentile may be used to identify IUGR infants correctly.

• A low neonatal ponderal index is defined as less than 1 SD below a mean 2.0.

• PI is usually less than 2 in assymmetric growth retarded baby and 2 or more in a baby who has either normal growth or has symmetrical growth retardation.

• Fetal ponderal index can also be calculated by USG examination and compared with neonatal P1. Fetal P1 had been found to be predictor of IUGR with the sensitivity and specificity of 76.9 and 82%, respectively. If the fetal P1 is less than 1 SD, the fetal and neonatal well being is compromised.

Apt Test

• The Apt test is most commonly used in cases of vaginal bleeding late during pregnancy (antepartum hemorrhage) to determine if the bleeding is from the mother or the fetus.

• Exposing the blood to NaOH (alkali) will denature the adult but not the fetal hemoglobin. The fetal hemoglobin will appear pinkish color under the microscope while the adult hemoglobin will appear as a yellow - brownish color. - Positive test à Blood is of fetal origin. - Negative test à Blood is of maternal origin.

• The Apt test can be used after birth (post partum hemorrhage) if the newborn has bloody vomiting, bloody stool, or active bleeding from nasogastric tube. A positive Apt test would mean that the blood is either due to GI or pulmonary bleeding from neonate. A negative Apt test would indicate that the blood is of maternal

origin, suggesting that the neonate swallowed or aspirated maternal blood, either during delivery or during breast feeding (from breast fissures). Kleihauer Betke test (KB test)

• The KB test is the standard test for detecting fetal - maternal hemorrhage. It is used to measure the amount of fetal hemoglobin transferred from a fetus to a mother’s blood stream.

• It is usually performed on Rh(-ve) mothers to determine the required dose of Rho (D) immunoglobulin to inhibit formation of Rh antibodies in the mother and prevent Rh hemolytic disease in future Rh - positive children.

• A standard blood smear is prepared from the mother’s blood and exposed to an acid bath. This removes adult hemoglobin, but not fetal hemoglobin, from the red blood cells. Subsequent staining makes fetal cells (containing HbF) appear rose pink, while adult red cells are only seen as ghosts.

• KB test quantifies the fetal - maternal hemorrhage.

Apt test Kleihauer Betke test

Source of sample Maternal or neonatal Maternal

How it works Adding 1% NaOH Adding acid destroys adult destroys adult HbA but HbA but not fetal HbF not fetal HbF

Assessment type Qualitative Quantitative

Results Positive means blood Reported in estimated ‘ml’s of is of fetal origin fetal blood

Hematopoesis in Fetus

• The anatomic sites of hematopoesis undergo developmental changes during embryonic and fetal life.

• RBC formation can be observed within the developing blood vessels of the yolk sac at 2 weeeks of gestation.

• By 8 weeks of gestation the site of RBC formation begins to shift to the sinusoids of the liver, where granulocyte precursors and megakaryocytes are also seen. Hematopoesis in the liver is maximal till 20-24 weeks and declines thereafter.

• Hematopoesis in the bone marrow is evident by the 4^th month of gestation and this becomes the predominant site of hematopoesis during the rest of gestation and later.

Hematopoiesis After Birth

• Upto puberty: It occurs throughout the seletaon.

• After puberty: Only the vertebrae, ribs, sternum, skull, pelvis and proimal epiphyseal regions of humerus and femur retain red marrow

Circulatory Adjustments at Birth

These are brought about because of a shift from placental dependance for gas exchange in the fetus to pulmonary gas exchange in neonate.

1. Pulmonary circulation: Immediatly after birth lungs expand due to first few breaths of neonate.

– This causes a fall in pulmonary vascular resistance (oxygen causes pulmonary vasodilatation).

– This results in increased flow into pulmonary trunk and arteries.

– The pulmonary artery pressure falls due to lowering of pulmonary vascular resistance.

– The pressure relations between aorta and pulmonary trunk are reversed so that the blood flow through the ductus arteriosus is reversed  Instead of blood flowing from the pulmonary artery to aorta, the direction of flow through ductus, is from aorta to pulmonary trunk.

– Increasing oxygen saturation causes the muscle of ductus to constrict  In full term neonates the ductus arteriosus closes within 10 to 25 days.

2. System circulation and circulation through heart

– Loss of placental circulation and clamping of the cord after birth results in increase in systemic vascular resistance.

– This tends to increase the aortic blood pressure and the left ventricular systolic pressure. The loss of placental circulation results in sudden reduction of flow through ductus venosus which closes off

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 Flow through ductus venosus disappears by the 7th day of posnatal life.

– The loss of placental flow results in a decrease in the volume of blood returning to right atrium

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 Right atrial pressure decreases.

– The left atrial pressure becomes higher than right atrial pressure and the septum primum which acts as a valve of fossa ovalis, approximates with the septum secundum to close off formen ovale.

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 Functional closure of foramen ovale occurs very quickly.

– Over a period of months, the septum primum and septum secundum become firmly adherent resulting in anatomical closure of the foramen ovale.

– After closure of ductus arteriosus, there is establishment of postnatal circulation:

– The blood reaching the right atrium through IVC and SVC is emptied into the right ventricle from where it is pumped into pulmonary trunk.

– After coursing through lungs for gas exchange, it reaches the left atrium and ventricle.

– The left venthcle pumps it out for distribution in the body for oxygenation of the tissues.

– The venous return again comes back to right atrium through IVC and SVC.

– All of the blood leaving the right ventricle, after coursing through lungs, reaches the left ventricle  The two ventricles are connected in series and therefore, the output of right and left ventricles are same (in contrast to fetal circulation, where right ventricular output is more).

Congenital Heart Disease

Left to right shunts (Acyanotic) Right to left shunts (cyanotic)

• VSD (MC congenital heart • Transposition of great arteries (MC

disease) cyanotic lesioin)

• ASD

• PDA

• VSD> ASD > PDA

• Tetralogy of Fallot

• Truncus arteriosus

• Tricuspid atresia

• TAPVR S-I-M 5Ts

ACYNOTIC CONGENITAL HEART DISEASE - LEFT TO