Module 7: Magdalena Flashcards
What are common complications of multiple pregnancies (3)?
- premature birth: about 60% twins born premature. length of pregnancy decrease with each additional baby (for twins, 35 weeks)
- low birth weight (LBW): more than half of twins born with LBW
- twin-to-twin transfusion syndrome (TTTS): occurs when a connection between the two babies’ blood vessels in the placenta causes one baby to get too much blood flow and the other too little
- gestational hypertension or preeclampsia: characterized by high blood pressure, protein in the urine, and generalized edema. baby must be delivered early to prevent serious complication
- gestational diabetes: This condition can cause the baby to grow especially large, increasing the risk of injuries to mother and baby during vaginal birth. Babies born to women with gestational diabetes also may have breathing and other problems during the newborn period.
What is Twin-to-Twin Transfusion Syndrome (TTTS)? treatment?
- TTTS occurs when a connection between the two babies’ blood vessels in the placenta causes one baby to get too much blood flow and the other too little.
- TTTS can be treated with laser surgery to seal off the connection between the babies’ blood vessels.
What are the two types of twins?
- identical (monozygotic): One egg is fertilized and splits to form two embryos. twins share placenta
- fraternal (dizygotic): Two separate eggs are fertilized by two separate sperm to form two separate embryos. separate placenta
What is the difference between monozygotic and dizgyotic twins?
monozygotic (identical)
- One egg is fertilized and splits to form two embryos.
- The fetuses share the same genetic material.
- When the split occurs will determines if the twins will share a placenta, with either one or two amnions, or if they each develop their own placenta.
- In general, the later the split occurs, the more likely that the twins will share one placenta
Dizygotic (fraternal):
- Two separate eggs are fertilized by two separate sperm to form two separate embryos.
- Fraternal twins are more common because each baby develops from a separate egg and sperm.
- Since each has a different egg and a different sperm, it is like siblings being born at the same time.
What is monochorionic diamniotic twins?
For monochorionic diamniotic twins:
- Fetuses share a single placenta.
- They are always identical twins.
- They have a higher risk for complications because two fetuses have to grow on a single placenta.
- The placenta is not always equally divided between the fetuses.
- Each fetus’s blood circulation is connected through blood vessels in the common placenta, and blood may pass disproportionately from one baby to the other, leading to the twin-to-twin transfusion syndrome. (TTTS).
What is dichorionic diamniotic twins?
For dichorionic diamniotic twins:
- Fetuses each have their own placenta with its own chorion and amnion.
- Most of these twins are fraternal; only a minority of these twins will be identical.
What is patent ductus ateriosus (PDA)?
- The ductus arteriosus is a normal pathway in the fetal circulatory system that allows blood to bypass the lungs and flow into the descending aorta to ultimately return to the placenta for oxygenation.
- After birth, as a result of decreasing pressure in the lungs and increased pressure in the aorta, the blood flow changes direction and flows from the aorta to the pulmonary artery (left-to-right shunt).
- Functional closure of the ductus normally occurs within the first few hours to several days after birth.
What is echocardiogram?
- a non-invasive procedure that uses high-frequency sound waves to generate a visual picture of the heart
- The examination allows for evaluation of anatomic structures, including valves, chambers, and vessels, and gives information about the structure and function of the heart, as well as the direction of blood flow through the heart.
What is the direction of blood flow through infants PDA?
- direction of blood flow through infants PDA is LEFT to RIGHT (aorta to pulmonary artery)
- After birth, as a result of decreasing pressure in the lungs and increased pressure in the aorta, the blood flow changes direction and flows from the aorta to the pulmonary artery (left-to-right shunt).
Why is blood being shunted from Left to Right in infant PDA?
- Blood is being shunted in this way because of the pressure gradient between the pulmonary artery and the aorta.
- This pressure gradient is such that the pressure in the aorta is higher than the pressure in the pulmonary artery.
- Blood flows along the path of least resistance: away from areas of higher pressure towards areas of lower pressure.
Why does PDA cause pulmonary hyperperfusion?
- A PDA allows blood to re-enter the pulmonary circuit, thereby increasing pulmonary blood flow.
What are 5 signs and symptoms of PDA that you would expect to see in preterm infant?
- Systolic murmur: due to blood shunting through the ductus arteriosus
- Wide pulse pressures: caused by the run-off of blood flow from the aorta to the pulmonary artery during diastole, therefore lowering diastolic BP and creating a widening pulse pressure
- Hypotension: due to a drop in diastolic pressure
- Bounding peripheral pulses: high stroke volume/wide pulse pressure
- Active precordium: due to increased volume of blood in left heart
**Congestive heart failure is often listed as a sign of PDA. This is certainly true; however, it is a later sign than the five signs listed above.
What is meant by the term “conservative management” for a patent ductus arteriosus?
Conservative management involves strategies:
- to decrease preload (fluid restriction),
- optimize gas exchange (respiratory support), and
- mitigate excessive pulmonary blood flow:
= permissive hypercapnia,
= avoiding metabolic alkalosis,
= avoiding excessive 02 supplementation
What are 3 potential medications that can be used for pharmacological treatment of a PDA?
- Indomethacin,
- ibuprofen, and
- acetaminophen
What are the potential side effects and contraindications of using acetaminophen to treat PDA?
side effects—unpredictable absorption when given enterally, potential for liver toxicity
Contraindications—none
What are the potential side effects and contraindications of using ibuprofen to treat PDA?
Side effects—oliguria, thrombocytopenia (can inhibit platelet aggregation), hyperbilirubinemia (can displace bilirubin from albumin), pulmonary hypertension
Contraindications—infection, active bleeding, thrombocytopenia, NEC, significant renal impairment
What are the potential side effects and contraindications of using indomethacin to treat PDA?
Side effects—renal impairment, oliguria, hyperkalemia, white matter damage, NEC, intestinal perforation, platelet dysfunction
Contraindications—thrombocytopenia, intracerebral hemorrhage, active bleeding, sepsis, liver damage with hyperbilirubinemia, intestinal perforation
What is head ultrasound (HUS)?
- uses sound waves positioned over the fontanelles to show the internal structures of the brain, including the ventricles and the blood vessels
When is head ultrasound routinely done in NICU?
- on preterm infants (less than 32 weeks) is on day 3–5 of life,
- at 32 weeks corrected, and
- at term to monitor for brain injury.
What is the most common type of intracranial hemorrhage seen in neonatal period?
Intraventricular hemorrhage (IVH)
- IVH mainly occurs in infants less than 32 weeks gestation, with the incidence increasing with decreasing gestational age
- Approximately half of all IVHs occur within the first 24 hours of life, and 95% within the first five days.
- This really highlights the importance of developmentally supportive care in those first few hours and days!
What are the 2 major risk factors for IVH in neonate?
prematurity:
- The periventricular area of the brain is growing rapidly and is richly supplied by blood vessels.
- These blood vessels are very thin.
- Pressure autoregulation is immature:
= Pressure autoregulation is a physiologic mechanism that functions to prevent increases in systemic blood pressure from creating increases in cerebral blood pressure.
= Pressure autoregulation is immature in preterm infants, meaning that any increase in systemic blood pressure creates an increase in cerebral blood pressure.
hypoxia:
- hypoxia leads to redistribution of blood flow such that more blood is delivered to vital organs—the heart and brain.
- In this way, hypoxia can lead to IVH by increasing cerebral blood flow through fragile blood vessels in the periventricular region of the brain.
- Any perinatal or neonatal event that results in hypoxia or alters cerebral blood flow increases the risk of IVH.
Why are preterm infants at risk for developing IVH (3)?
- They have limited abilities to autoregulate cerebral blood pressure: increases in systemic blood pressure result in higher cerebral blood pressures.
- They are at risk for respiratory distress and hypoxia: causes increased blood flow to the brain (and heart).
- Their blood vessels are thin-walled and fragile: rupture easily if either pressure and/or volume increase.
- The periventricular (subependymal) region of the brain is growing and developing at a rapid pace and is well supplied with blood vessels: therefore, the most vulnerable area for hemorrhage.
- They are frequently stressed by painful, invasive, or uncomfortable procedures: Stress can lead to both hypoxia and elevated blood pressure.
- They frequently need hypertonic IV solutions, volume expansion, and medications: can rapidly expand the intravascular space, leading to increased intracranial blood volume and pressure.
- Hypotension – the fragile germinal matrix of preterm infants is vulnerable at both ends of normal blood pressure boundaries and is especially unable to handle large fluctuations in blood pressure.
- Infection – preterm infants who experience infection either prenatally or postnatally are at an increased risk for IVH.
- Acidosis – severe acidosis is associated with higher odds of IVH in preterm infants.
- Coagulopathy – severe derangement of coagulation is associated with increased risk for IVH in preterm infants.
What are potential cues infant might display would alert to consider the possibility of IVH (3)?
- decreased muscle tone (flaccidity)
- tonic posturing
- hypotension
- level of alertness and state
- apnea
- sudden drop in hematocrit
- pallor, mottling
- temperature instability
- full or tense fontanelle
- seizures
- oculomotor disturbances (abnormal eye movements)
What are nursing strategies we can use to prevent IVH in infants (3)?
- Keep head in a midline position for the first 24h of life (*few initial studies showed positive outcomes).
- Administer prenatal glucocorticoids
- Maintain oxygenation.
- Regulate acid-base balance.
- Ensure IV fluids and medications are administered at the appropriate rates.
- Minimize stress with pain management and comfort measures (DSC).
- Reduce and pace handling.
- Maintain normal body temperature.
- Provide adequate calories, nutrients, and fluids.
- Protect newborn from infection.
- Monitor and maintain blood pressure.
- Suction only as needed.
What is Hypoxic-Ischemic Encephalopathy (HIE)?
- combination of hypoxia and ischemia is a common cause of brain injury in both term and preterm infant
- Hypoxia: low levels of oxygen
- ischemia: low levels of perfusion
**HIE may be due to any condition leading to decreased oxygen supply (hypoxia) and decreased blood supply (ischemia).
What is the first initial insult of HIE?
Hypoxemia and/or ischemia cause:
- a deprivation of glucose and oxygen supply to the brain, which causes a primary energy failure and initiates a cascade of biochemical events that lead to cell dysfunction and ultimately to cell death.
The Sympathetic Nervous System is stimulated:
- resulting in shunting of blood to vital organs (brain, heart, and adrenals) to maintain adequate cardiac output and cerebral perfusion.
- As the hypoxic-ischemic event progresses, there is a decrease in cardiac output and cerebral perfusion, which leads to anaerobic metabolism.
- As the brain reverts to anaerobic metabolism, it causes a rapid depletion of high-energy phosphate reserves (ATP).
- Cellular function is compromised, resulting in an increase of intracellular sodium, calcium and water, tissue acidosis, and electrical failure of neural tissue.
What is the reperfusion injury of HIE?
- This phase is where irreversible cell death begins (6–18 hours after oxygenation and perfusion has been restored).
-The phase begins with a brief period of restored cellular function (normal vital signs, pH, absence of seizures). - Clinical deterioration quickly follows because of mitochondrial dysfunction as a result of the initial insult, and continued cell injury and cell death can occur.
- The period between the primary phase of injury and the secondary phase is the therapeutic window for potential neuro-protective interventions
