Tricuspid Atresia in a newborn - Nursing Case Study

Pathophysiology

• Primary mechanism: Tricuspid atresia is a congenital heart defect where the tricuspid valve doesn't develop, leading to a missing or abnormally developed right ventricle. This blocks the normal blood flow from the right atrium to the right ventricle, decreasing oxygen supply to the body.

• Secondary mechanism: Atrial septal defect or a patent foramen ovale (holes in the wall between the atria) often coexist, allowing some oxygen-poor blood to flow into the left atrium. Oxygen-rich and oxygen-poor blood mix here and is pumped into the body, causing cyanosis.

• Key complication: Over time, the extra workload on the left ventricle can lead to heart failure. Additionally, the lack of a normal right ventricle and tricuspid valve can cause an increase in pressure in the veins bringing blood back to the heart from the body, leading to liver and other organ damage.

Patient Profile

Demographics:

Newborn (2 weeks old), Female

History:

• No past medical history (newborn)

• No current medications

• No known allergies

Current Presentation:

• Chief complaint: Feeding difficulties, extreme lethargy, and cyanosis (blue coloration of the skin)

• Key symptoms: Shortness of breath, weak pulse, poor weight gain, and abnormal heart sounds

• Vital signs: Heart rate 180 bpm, Respiratory rate 65 breaths per minute, Oxygen saturation 72%, Temperature 36.8°C, Blood pressure 70/45 mmHg

Section 1

Change in patient status:

Over the next several hours, the newborn's condition continues to deteriorate. Her heart rate increases to 200 bpm while her oxygen saturation drops to 68%. She becomes increasingly lethargic and her cyanosis deepens, indicating an increased inability for her body to oxygenate tissues effectively. Her respiratory rate also escalates to 75 breaths per minute, signaling respiratory distress. On auscultation, the abnormal heart sounds have become more pronounced, suggesting an exacerbation of the existing heart condition.

The nurse also notes that the newborn's abdomen appears distended, a potential sign of liver congestion due to increased pressure in the veins carrying blood back to the heart. The nurse also palpates a firm liver edge extending 2 cm below the right costal margin. The newborn's weight continues to drop, reflecting poor feeding and possible organ damage. These changes in the patient's status indicate a worsening of her condition, likely due to the increased workload on the left ventricle and the lack of a normal right ventricle and tricuspid valve. The newborn's condition mandates immediate intervention to prevent further deterioration and organ damage.

Section 2

New diagnostic results:

The neonatal Intensive Care Unit (NICU) team decides to perform an echocardiogram to further evaluate the newborn's heart condition. The results show an underdeveloped right ventricle and a complete blockage of the tricuspid valve, confirming the diagnosis of tricuspid atresia. Additionally, the echocardiogram reveals an atrial septal defect, which allows some oxygen-rich blood to mix with oxygen-poor blood, providing a temporary oxygen supply to the body. However, this is not a long-term solution, as noted by the newborn's worsening condition.

The newborn's labs return with an elevated B-type natriuretic peptide (BNP) level of 900 pg/mL, which is indicative of heart failure. Her arterial blood gas (ABG) results show a pH of 7.28, a PaCO2 of 50 mmHg, a PaO2 of 60 mmHg, and a bicarbonate level of 22 mEq/L, indicating respiratory acidosis and hypoxemia. These results are consistent with the newborn's increased respiratory rate and decreased oxygen saturation, confirming the newborn is struggling to oxygenate her body effectively. The combination of the diagnostic results and the newborn's physical presentation emphasizes the urgent need for intervention.

Section 3

Change in Patient Status:

Over the next 24 hours, the newborn's condition continues to deteriorate. She becomes increasingly lethargic and her respiratory distress intensifies, with her respiratory rate increasing to 70 breaths per minute and her oxygen saturation dropping to 85% despite an increased flow of oxygen via nasal cannula. Her color is pale and her extremities are cool to touch, which indicates poor peripheral perfusion. Her heart rate is also elevated at 180 beats per minute.

The team notes a decrease in the baby's urinary output (0.5 mL/kg/hr), which may signal decreased kidney function due to poor cardiac output. Additionally, the baby's abdomen appears to be distended and firm to touch - a possible sign of hepatic congestion due to right-sided heart failure. These new findings are concerning, as they suggest the baby's heart is not effectively pumping blood to her body, leading to a decrease in oxygen and nutrient supply to her organs. The NICU team needs to act swiftly to address these signs of decompensating heart failure.

Section 4

New Diagnostic Results:

Urgent echocardiography confirms the diagnosis of tricuspid atresia, showing a small right atrium, an absent or diminutive tricuspid valve, and an atrialized section of the right ventricle. The newborn's blood tests reveal a significant metabolic acidosis with a blood pH of 7.22 and a bicarbonate level of 17 mEq/L. Her lactate level is also elevated at 5 mmol/L, indicating tissue hypoperfusion.

The complete blood count shows a high white blood cell count of 20,000 per microliter, suggesting a possible infection. Her hemoglobin level is 15 g/dL, which is normal for her age, but her hematocrit is at 45%, indicating a possible response to chronic hypoxia. Her kidney function tests are also abnormal with blood urea nitrogen (BUN) at 30 mg/dL and creatinine of 1.2 mg/dL, further confirming decreased renal perfusion. These results indicate worsening cardiac output, leading to multi-organ dysfunction. The team decides to consult with the pediatric cardiology team for emergent intervention, knowing that timely decision-making is crucial in preventing further decompensation.

Section 5

The pediatric cardiology team quickly arrives to review the newborn's current condition. The initial assessment reveals an increased heart rate of 170 beats per minute, and a respiratory rate of 60 breaths per minute. The newborn's oxygen saturation has dropped to 85% on room air. On auscultation, a heart murmur is noted, consistent with the echocardiography findings. The baby's skin is cool and mottled, a sign of poor perfusion. Capillary refill time is prolonged, at 4 seconds, and there is noted hepatomegaly on abdominal palpation.

The medical team decides to initiate prostaglandin E1 infusion to keep the ductus arteriosus open, ensuring blood flow to the lungs and systemic circulation. The baby is also started on broad-spectrum antibiotics, considering the elevated white blood cell count and the potential for sepsis. Despite these interventions, the baby's blood gas analysis after an hour shows a worsening metabolic acidosis with a blood pH of 7.18, bicarbonate of 15 mEq/L, and a lactate level of 7 mmol/L. These findings suggest that the baby's condition is deteriorating, likely due to inadequate cardiac output and tissue perfusion, emphasizing the need for more aggressive measures.