Severe Pulmonary Hypertension with Extracorporeal Membrane Oxygenation - Nursing Case Study

Pathophysiology

• Primary mechanism: Severe pulmonary hypertension results from persistently high blood pressure in the arteries of the lungs. This leads to increased resistance in the pulmonary vasculature, straining the right side of the heart and leading to right heart failure.

• Secondary mechanism: In response to severe pulmonary hypertension, the body may reduce blood flow to the lungs, leading to hypoxemia or low blood oxygen levels. This exacerbates the strain on the heart and can lead to organ damage due to inadequate oxygen supply.

• Key complication with ECMO: ECMO (Extracorporeal Membrane Oxygenation) is used as a life support mechanism in severe cases. It oxygenates blood outside the body, bypassing the lungs. However, it can lead to complications like bleeding, infection, and organ damage due to the invasive nature of the treatment and potential for blood clots.

Patient Profile

Demographics:

72-year-old female, retired school teacher

History:

• Key past medical history: Diagnosed with Severe Pulmonary Hypertension 4 years ago, history of chronic obstructive pulmonary disease (COPD), previous episode of pneumonia

• Current medications: Warfarin, Digoxin, Furosemide, Bosentan, Sildenafil, Supplemental oxygen therapy

• Allergies: Penicillin

Current Presentation:

• Chief complaint: Progressive shortness of breath, fatigue, and fainting spells

• Key symptoms: Worsening breathlessness, chest pain, syncope, lower extremity edema

• Vital signs: Blood pressure 115/70 mmHg, pulse 105 bpm, respiratory rate 28 breaths per minute, oxygen saturation 82% on room air, temperature 98.2°F

Section 1

New Diagnostic Results:

Upon further investigation, a transthoracic echocardiogram (TTE) was performed, revealing significant right ventricular hypertrophy, indicating an enlargement of the heart's right ventricle due to the increased pressure in the pulmonary arteries. Furthermore, a right heart catheterization confirmed severe pulmonary hypertension, with a mean pulmonary artery pressure of 60 mmHg (normal range 10-20 mmHg) and a pulmonary vascular resistance of 8 Woods units (normal range 1-3 Woods units).

The patient's blood gas analysis showed pH 7.32 (normal range: 7.35-7.45), PaCO2 55 mmHg (normal range: 35-45 mmHg), PaO2 60 mmHg (normal range: 80-100 mmHg), HCO3 29 mEq/L (normal range: 22-28 mEq/L), indicating respiratory acidosis with compensatory metabolic alkalosis, a common finding in patients with severe COPD. The worsening of the patient's breathlessness and lower oxygen saturation, despite supplemental oxygen therapy, suggests the progression of her pulmonary hypertension and COPD.

These findings necessitate immediate medical intervention to manage the patient's severe pulmonary hypertension and prevent further deterioration of her condition. The clinical team must consider the risks associated with ECMO, including bleeding, infection, and organ damage, while also recognizing its potential to improve the patient's oxygenation and alleviate strain on her heart. The patient's warfarin therapy may need to be adjusted to mitigate the risk of bleeding associated with ECMO.

Section 2

Response to Interventions:

Due to the severity of the patient's condition, the medical team decided to initiate ECMO support after carefully considering the associated risks. The patient was anticoagulated with heparin instead of warfarin to reduce the risk of bleeding. Initial settings for the ECMO machine were set at a blood flow rate of 3.5 L/min and sweep gas flow rate of 2 L/min.

Post initiation of ECMO, the patient's oxygen saturation improved significantly to 92% on a FiO2 of 60% and her respiratory rate decreased from 30 breaths per minute to a more comfortable 18 breaths per minute. However, despite the improvement on ECMO, the patient's hemodynamic status remained unstable. Her blood pressure dropped to 90/60 mmHg from a baseline of 130/85 mmHg and her heart rate increased to 110 beats per minute from 80 beats per minute. These findings suggest possible complications such as bleeding or cardiac tamponade necessitating urgent further evaluation. The clinician must carefully assess these changes and consider the need for additional interventions such as vasopressor support or exploration for possible bleeding.

Section 3

Change in Patient Status:

Almost 24 hours after initiation of ECMO, the patient's blood pressure remained consistently low at 90/60 mmHg and her heart rate was still elevated at 110 beats per minute. The team's concern escalated when the patient suddenly became acutely confused and agitated. Her Glasgow Coma Scale (GCS) score dropped from 15 to 12, and her pupils were noted to be unequal with the left pupil 3 mm and the right pupil 5 mm, neither reactive to light. These changes prompted the team to suspect intracranial bleeding, a serious complication of anticoagulation therapy.

New Diagnostic Results:

An urgent non-contrast CT head was ordered, which revealed a small subdural hematoma on the right side. Additionally, laboratory results showed a significant drop in her hemoglobin from 12 g/dL to 8 g/dL and her platelet count was 90,000 per microliter, down from a baseline of 200,000 per microliter. Her activated partial thromboplastin time (aPTT) was elevated at 70 seconds, indicating a high risk of bleeding due to excessive anticoagulation. This new information confirmed the team's suspicion of intracranial bleeding and posed a complex challenge of balancing the risk of clotting in the ECMO circuit against the risk of worsening intracranial bleeding.

Section 4

New Complications:

As the patient's condition continued to deteriorate, her blood pressure further dropped to 85/50 mmHg, and her heart rate increased to 120 beats per minute. The patient also started to exhibit signs of increased intracranial pressure such as worsening confusion, restlessness, and a decreased level of consciousness. Her GCS score further dropped to 9, indicating a serious deterioration in her neurological status. To add to the complexity, her oxygen saturation levels started to decrease from 95% to 88%, suggesting possible clot formation in the ECMO circuit or worsening pulmonary hypertension.

The nursing team quickly responded by notifying the physician and intensivist on call. Inotropic support was initiated to maintain her blood pressure and the anticoagulation therapy was adjusted under the guidance of the hematologist to prevent further intracranial bleeding. The respiratory therapist was also called to assess the ECMO circuit for any signs of clotting. Despite these interventions, the patient's condition remained critical, setting the stage for a challenging course of treatment and care. The team now had to think critically about the feasibility of continuing ECMO therapy and dealing with the potential complications, while ensuring the patient's safety and wellbeing.

Section 5

Change in Patient Status:

Despite the interventions, the patient's vital signs continued to decline. Her blood pressure dropped further to 75/45 mmHg and heart rate increased to 130 beats per minute. The oxygen saturation levels also plummeted to 80%, indicating severe hypoxia. Furthermore, the patient's neurological status worsened, with her GCS score dropping to 7. She became less responsive and showed signs of anisocoria, with the left pupil becoming larger than the right.

The patient's deteriorating condition raised serious concerns about the effectiveness of the current interventions and the development of potential new complications such as an intracranial hemorrhage or even brain herniation due to the increased intracranial pressure. The team had to reassess their approach and consider additional diagnostic tests to evaluate the cause of the neurological changes and persistent hypoxia. The intensivist also suggested the possibility of transitioning the patient to a more advanced form of ECMO or even considering a lung transplant, given the severity of her pulmonary hypertension.