Ventricular Septal Defect in an infant - Nursing Case Study

Pathophysiology

• Primary mechanism: Ventricular Septal Defect (VSD) in an infant involves an opening in the septum that separates the right and left ventricles of the heart. This hole allows oxygen-rich blood from the left ventricle to mix with oxygen-poor blood in the right ventricle, leading to oxygenated blood being pumped back to the lungs instead of the body.

• Secondary mechanism: The excessive blood flow to the lungs due to VSD puts extra pressure on the heart and pulmonary arteries. Over time, this can cause the heart to enlarge and pump harder, potentially leading to heart failure.

• Key complication: The increased blood flow and pressure in the lungs due to VSD can eventually cause pulmonary hypertension, a serious condition where the blood vessels in the lungs become narrow and damaged, leading to breathing difficulties and decreased oxygen levels in the blood.

Patient Profile

Demographics:

6 months old, male, no occupation

History:

• Key past medical history: Born premature at 32 weeks, frequent episodes of respiratory infections

• Current medications: Furosemide, Spironolactone

• Allergies: No known drug allergies

Current Presentation:

• Chief complaint: Persistent cough, feeding difficulties, and sweating

• Key symptoms: Fast breathing, poor weight gain, excessive sweating particularly during feeds, fatigue, and a bluish tint to the skin (cyanosis)

• Vital signs: Increased heart rate (170 beats per minute), increased respiratory rate (50 breaths per minute), oxygen saturation at 88% on room air, blood pressure at 70/45 mmHg, temperature at 98.6°F.

Section 1

Change in Patient Status:

Throughout the day, the infant's condition deteriorates. His respiratory rate increases to 60 breaths per minute and oxygen saturation drops to 84% on room air. His heart rate remains high at 180 beats per minute and his blood pressure is slightly decreased at 65/40 mmHg. The cyanosis becomes more pronounced, particularly around the lips and nail beds. The infant appears lethargic and struggles to stay awake during feeds, often falling asleep before finishing.

The patient also develops edema in his lower extremities, a sign of worsening heart failure. His weight increases by 200 grams overnight, likely due to fluid retention. On auscultation, a loud harsh holosystolic murmur is heard at the left lower sternal border, indicative of the increased blood flow through the VSD. Crackles are also heard on lung auscultation, suggesting pulmonary edema. The infant's deteriorating condition, combined with the physical exam findings, indicates that his heart failure is progressing and his body is struggling to compensate for the VSD.

These changes in the patient's status require immediate medical attention. The healthcare team needs to consider adjusting the current medications or introducing new ones to better manage the infant's heart failure and pulmonary hypertension. Moreover, the possibility of surgical intervention to correct the VSD should be discussed. This situation calls for clinical reasoning to balance the risks and benefits of the available treatment options, keeping in mind the patient's age, size, and overall health status.

Section 2

Change in Patient Status:

Following the worsening condition, the healthcare team decides to initiate further diagnostic tests to assess the severity of the heart failure and the extent of the VSD. The echocardiogram shows an enlarged left ventricle and an increased shunting of blood through the VSD, further suggesting a worsening heart condition. In addition, the B-type natriuretic peptide (BNP) level, a key marker for heart failure, rises to 900 pg/mL, well above the normal range of less than 100 pg/mL for infants.

In response to these findings, the healthcare team adjusts the infant's treatment plan. The dose of diuretics is increased to help manage the fluid retention and pulmonary edema. The team also adds an angiotensin-converting enzyme (ACE) inhibitor to the medication regimen to help reduce the workload on the heart and improve heart function. The infant's oxygen saturation improves slightly to 88% with these interventions, but his respiratory rate remains high and he continues to struggle with feeds. The healthcare team is closely monitoring the infant's response to these interventions while also considering the potential need for surgical intervention. These decisions require careful clinical reasoning, taking into account the infant's current condition, potential risks and benefits, and the urgency of the situation.

Section 3

New Diagnostic Results:

Despite the interventions, the infant's condition does not show significant improvement. The healthcare team therefore decides to conduct further diagnostic tests to gain a better understanding of the situation. A cardiac catheterization is performed to measure the pressures within the heart chambers and the pulmonary artery, as well as to get a closer look at the anatomy of the VSD. The results reveal a pulmonary artery pressure of 22 mmHg, significantly higher than the normal range of 8-20 mmHg for infants, indicating increased pressure in the blood vessels of the lungs due to the left-to-right shunt. The size of the VSD is also noted to be large, which explains the severe symptoms and signs.

In addition, new blood tests show an elevated lactate level of 4.2 mmol/L, which is above the normal range of 0.5-2.2 mmol/L, suggesting that the infant's tissues are not getting enough oxygen. This could be due to the heart's inability to pump enough blood, leading to insufficient oxygen supply to the body. The infant's hemoglobin level is also found to be low at 9.2 g/dL, potentially contributing to the oxygen supply problem.

This new information calls for a reevaluation of the current treatment strategy. The healthcare team must now consider whether the current medications are sufficient or if the infant's condition warrants more aggressive interventions, such as surgical repair of the VSD. This decision involves a complex process of clinical reasoning, considering the potential risks and benefits, the infant's current condition, and the urgency of the situation.

Section 4

Change in Patient Status:

Over the next 24 hours, the infant's condition continues to deteriorate. Despite supplemental oxygen therapy, the infant's oxygen saturation levels remain low, ranging between 85-90%. The infant also becomes increasingly tachypneic, with a respiratory rate averaging around 60 breaths per minute. The infant’s heart rate also remains elevated at 180 beats per minute, and the infant appears uncomfortable, often crying and difficult to soothe.

The infant's feeding tolerance also decreases, with the infant often becoming fatigued during feeds and only able to take half of the usual volume. The infant's weight has decreased by 5% from birth weight, indicating poor growth and feeding issues. These changes in the infant's status, combined with the new diagnostic results, signal the need for a significant shift in the treatment approach. The healthcare team must now grapple with whether to escalate treatment to surgical intervention to correct the VSD, weighing the potential risks of surgery against the increasing risk of the infant's declining health status.

Section 5

New Complications:

The next day, the infant's condition further deteriorates. The healthcare team notes an increased work of breathing, with nasal flaring and subcostal retractions evident. The infant's oxygen saturation levels drop further, averaging around 82-87%, even with the supplemental oxygen therapy. Auscultation of the chest reveals decreased breath sounds on the left side, suggesting potential development of a pneumothorax, a known complication of VSD.

In addition to respiratory complications, the infant's feeding issues escalate. Despite a change to high-calorie formula and feeding via a nasogastric tube, the infant continues to lose weight, now down 8% from birth weight. Blood tests also show hyponatremia and hypokalemia, suggesting that the infant may be experiencing malnutrition and dehydration. This combination of respiratory and nutritional complications further complicates the decision-making process regarding surgical intervention. The team must consider the infant's ability to withstand surgery and potential post-operative complications, given the current compromised health status.