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Pulmonary Hypertension and Thoracic Care: Comprehensive Study Notes

Pulmonary Hypertension: Definition, Epidemiology, and Pathophysiology

  • Pulmonary hypertension (PH) is elevated pulmonary artery pressure due to increased resistance to blood flow through the pulmonary circulation.
  • Mean pulmonary artery pressures (MPAP):
    • Normal MPAP: 12\text{ to }16\ \text{mmHg}
    • At rest, PH considered when MPAP >25\ \text{mmHg}
    • With exercise, MPAP >30\ \text{mmHg}
  • PH can be a primary disease or a secondary complication of another disorder.
  • Etiology involves endothelial injury leading to vascular remodeling: endothelial dysfunction, vascular scarring, and smooth muscle proliferation.
  • Pathophysiology sequence: insult to pulmonary endothelium → endothelial dysfunction → smooth muscle proliferation and vascular remodeling → increased pulmonary vascular resistance → elevated MPAP → right heart strain.
  • Epidemiology: females are affected more than males in Group 1 IPAH; higher risk without known cause in IPAH.
  • If untreated, PH can progress to right-sided heart failure (cor pulmonale) and death.

World Health Organization (WHO) Groups of Pulmonary Hypertension

  • Group 1: Pulmonary arterial hypertension (PAH) – disease of the small pulmonary arteries; artery enlargement and remodeling.
    • Idiopathic PAH (IPAH): typically in young women; unknown cause; may have genetic links or be associated with medications or specific diseases.
  • Group 2: PH due to left-sided heart failure.
  • Group 3: PH due to lung disease and/or hypoxemia.
  • Group 4: PH due to thromboembolic occlusion (cardiovascular system with thromboembolic disease).
  • Group 5: Multifactorial – hematologic or metabolic involvement (e.g., complex systemic diseases).

Group 1: Idiopathic Pulmonary Arterial Hypertension (IPAH)

  • IPAH is PH without an identifiable cause after evaluation.
  • Characteristics:
    • Often affects young women; unknown etiology.
    • Can have genetic predisposition or associations with certain drugs or diseases.
  • Pathophysiology involves progressive constriction and remodeling of small pulmonary arteries leading to increased pulmonary vascular resistance.

Group 2: Left-Sided Heart Failure

  • PH results from backward pressure transmitted from the left heart into the pulmonary circulation.
  • Blood backs up into the pulmonary vasculature, increasing pressures and leading to PH.

Group 3: Lungs and Hypoxemia

  • PH due to chronic lung diseases (e.g., COPD, interstitial lung disease) and/or chronic hypoxemia.
  • Hypoxic vasoconstriction and vascular remodeling contribute to elevated pulmonary pressures.

Group 4: Cardiovascular System and Thromboembolic Occlusion

  • Thromboembolic disease (e.g., chronic thromboembolic pulmonary hypertension, CTEPH) narrows or occludes pulmonary arteries.
  • Recurrent or unresolved clots reduce flow and raise resistance in the pulmonary circulation.

Group 5: Multifactorial: Hematologic or Metabolic Involvement

  • PH associated with hematologic or metabolic disorders (e.g., sickle cell disease, sarcoidosis).

Etiology, Presentation, and Diagnostics of Pulmonary Hypertension

  • PH without known cause can progress to right heart failure and death if untreated.
  • Etiology in some cases remains uncertain but may relate to connective tissue disease, cirrhosis, or HIV.
  • Pathophysiology hallmark: injury to pulmonary endothelium with subsequent vascular remodeling.
  • Diagnostic emphasis: evaluate for group classification; females affected more than males in IPAH.
  • Classic clinical manifestations: dyspnea on exertion and fatigue; other symptoms include exertional chest pain, dizziness, and syncope; abnormal heart sounds.
  • Disease progression signs: dyspnea at rest, right ventricular hypertrophy (RVH).
  • Diagnostic studies include:
    • Right-sided heart catheterization with:
    • Pulmonary artery pressure measurement
    • Cardiac output
    • Pulmonary vascular resistance
    • Electrocardiography (ECG)
    • Chest radiography
    • Pulmonary function tests
    • Echocardiography
    • Computed tomography (CT) scan

Clinical Manifestations and Diagnostic Studies for Pulmonary Hypertension

  • Classic symptoms: dyspnea on exertion, fatigue.
  • Other symptoms: exertional chest pain, dizziness, syncope, abnormal heart sounds.
  • Signs of progression: dyspnea at rest, RVH on ECG, increased S2 intensity, polycythemia.
  • Key diagnostic tool: Right-sided heart catheterization to measure pulmonary pressures and hemodynamics.
  • Additional assessments: ECG, chest x-ray, PFTs, echocardiography, CT scan.

Management and Therapeutic Approaches in Pulmonary Hypertension

  • Early recognition aims to halt progression.
  • Pharmacologic therapy focuses on:
    • Pulmonary vasodilation
    • Reducing right ventricular overload
    • Reversing remodeling where possible
  • Supportive and disease-modifying measures:
    • Manage fluid status with diuretics to treat edema
    • Anticoagulation to prevent thrombi (where appropriate)
    • Maintain oxygen saturation (target > 90\%) to prevent hypoxia-induced vasoconstriction
  • Specific interventional and surgical options:
    • Thromboendarterectomy (for chronic thromboembolic PH)
    • Atrial septostomy (to decompress the right heart in select cases)
    • Lung transplantation for end-stage disease
  • Nursing and interprofessional management:
    • Education, monitoring, and coordination of care

Cor Pulmonale and Right Ventricular Failure

  • Cor pulmonale refers to enlarged right ventricle secondary to chronic respiratory system disorders (most commonly COPD).
  • Pathophysiology: Chronic hypoxic vasoconstriction and increased afterload cause RV hypertrophy and eventual failure.
  • Manifestations include exertional dyspnea, tachypnea, cough, fatigue; signs include RV hypertrophy on EKG, accentuated S2, polycythemia.
  • May lead to peripheral edema, weight gain, distended neck veins, hepatomegaly, and congestive symptoms.

Pathophysiology Map of Pulmonary Hypertension and Cor Pulmonale

  • Insult occurs (hormonal, mechanical, or other) → pulmonary endothelial injury
  • Endothelial injury leads to smooth muscle proliferation and vascular scarring
  • Sustained pulmonary hypertension develops → right ventricular hypertrophy
  • Progression to cor pulmonale and eventually right-sided heart failure

Lung Transplantation: Indications, Evaluation, and Allocation

  • Indication: End-stage lung disease, including COPD, idiopathic pulmonary fibrosis, cystic fibrosis, PAH, emphysema with A1-antitrypsin deficiency.
  • Preoperative care involves comprehensive evaluation and determination of suitability.
  • UNOS (United Network for Organ Sharing) and the Lung Allocation Score (LAS) govern listing and allocation.

Lung Transplantation: Surgical and Postoperative Aspects

  • Surgical procedures include four types:
    • Single-lung transplantation
    • Bilateral lung transplantation
    • Heart-lung transplantation
    • Lobes from living-related donor
  • Postoperative care is intensive and typically in the ICU with ventilatory support, IV fluids, and immunosuppression.
  • Immunosuppressive regimen commonly includes tacrolimus, mycophenolate mofetil, and prednisone (drug details discussed in accompanying tables).
  • Nutrition support and monitoring for infection and rejection are essential.

Rejection in Lung Transplantation

  • Acute rejection typically occurs 5–10 days after transplantation: fever, fatigue, dyspnea, dry cough, O2 desaturation.
  • Diagnosed by biopsy via bronchoscopy.
  • Treated with high-dose IV corticosteroids.
  • Chronic rejection manifests as bronchiolitis obliterans syndrome (BOS): progressive airflow obstruction not responsive to bronchodilators or corticosteroids; may require additional immunosuppressive therapy.
  • Discharge planning includes infection prevention, self-care, medication management, contact with transplant team, pulmonary hygiene, and rehabilitation.

Thoracic Surgery: Preoperative and Intraoperative Considerations

  • Thoracotomy refers to surgical incisions into the chest wall.
  • Common incisions include:
    • Median sternotomy
    • Lateral thoracotomy
  • Other procedures may involve specific access depending on the operation.

Thoracic Surgeries: Common Procedures

  • Wedge resection
  • Segmentectomy
  • Lobectomy
  • Pneumonectomy
  • Structural variations include single-lung vs bilateral approaches and combinations with other procedures.
  • Video-assisted thoracic surgery (VATS) is a minimally invasive approach.

Video-assisted Thoracic Surgery (VATS)

  • Definition: Minimally invasive surgery using a 2-D video image of the chest cavity.
  • Indications: Diagnosis and treatment of pleural diseases, pulmonary masses and nodules, mediastinal masses, interstitial lung disease, and chest trauma.
  • Advantages: Less postoperative pain, shorter hospital stay, lower morbidity, fewer complications, faster return to normal activities.

Preoperative and Postoperative Cardiopulmonary Assessment

  • Preoperative assessment includes:
    • Cardiopulmonary status evaluation
    • Chest x-ray, ECG, PFTs, blood tests (BUN, creatinine, glucose, electrolytes), coagulation studies, CBC
    • Anesthesia consultation
    • Smoking cessation counseling
  • Patient education includes postoperative care expectations, oxygen therapy, airway management, IV fluids, transfusion needs, and chest tube management.
  • Postoperative care emphasizes pain management, respiratory therapy (incentive spirometry, coughing, deep breathing), chest tube management, and monitoring for complications.

Pain Management and Respiratory Support Postoperatively

  • Pain control modalities include patient-controlled analgesia (PCA), epidural analgesia, and nerve blocks.
  • Assess respiratory status: respiratory rate, effort, breath sounds, sputum volume and color, chest tubes, and chest radiographs.
  • Vigilance for infection: monitor temperature and systemic signs.

Thoracentesis: Diagnostic and Therapeutic Fluid Removal

  • Thoracentesis involves aspiration of pleural fluid for diagnosis and therapy.
  • Typical removal: about 1000$-$1200\ \text{mL}; larger volumes can cause hypotension, hypoxemia, or re-expansion pulmonary edema.
  • Post-procedure: chest x-ray to assess for pneumothorax; monitor vital signs, oxygen saturation, and respiratory status.

Chest Trauma and Thoracic Injuries

  • Ribs: The most common chest injury from blunt trauma; ribs 5–9 are most frequently fractured due to being least protected by chest wall muscles.
  • Complications of displaced rib fractures include injury to the pleura, lungs, heart, and other internal organs.
  • Pain with inspiration and coughing leads to splinting and shallow breathing, increasing risk of pneumonia and atelectasis.

Management of Chest Trauma: Pain Control and Respiratory Therapy

  • Goals: decrease pain to promote adequate ventilation and clearance of secretions.
  • Analgesia options include NSAIDs, opioids, and thoracic nerve blocks.
  • Emphasize deep breathing, coughing, incentive spirometry, and appropriate use of analgesics to prevent pulmonary complications.

Flail Chest: Definition, Consequences, and Management

  • Flail chest: 3 or more consecutive ribs in 2 or more places fracture, causing chest wall instability.
  • Leads to paradoxical chest wall movement (paradoxical breathing) and inefficient ventilation.
  • Management focuses on ensuring adequate ventilation and oxygenation, analgesia, and sometimes mechanical ventilation.
  • Severe cases may require surgical stabilization of the chest wall.

Pneumothorax: Types and Management

  • Pneumothorax is the collapse of a lung due to air in the pleural space.
  • Types include spontaneous pneumothorax (blebs rupture on lung surface), iatrogenic pneumothorax (puncture during a procedure), tension pneumothorax (air in pleural space with no exit), Hemothorax (blood in pleural space), and Hemopneumothorax (air and blood in pleural space).

Tension Pneumothorax

  • A medical emergency where air enters the pleural space but cannot escape, causing rapid pressure buildup and mediastinal shift.

Pneumothorax, Hemothorax, and Hemopneumothorax: Visual Summary

  • Pleural cavity complications:
    • Pneumothorax: collapsed lung with air in pleural space
    • Hemothorax: blood in pleural space
    • Hemopneumothorax: both air and blood in pleural space

Chest Tubes and Drainage Systems

  • Chest tube insertion location typically depends on the issue (air vs fluid).
  • Common insertion guidelines include the second intercostal space for air drainage and other sites for fluid drainage.
  • Chest tube drainage units (CDU) come in two major types:
    • Wet suction: suction provided by a collection chamber with water seal; suction typically set to overcome approximately 20\ \text{cm H}_2\text{O} pressure.
    • Dry suction: fixed or adjustable suction settings, controlled without a water column.
  • Dry suction allows higher or lower suction as required by clinical goals.
  • Flutter valve (Heimlich valve) is another drainage option for certain pneumothorax patients.

CDU: Close-Up Takeaways for Nursing and Clinician Practice

  • When assessing a CDU setup:
    • Know the type of CDU in place and why it is used for the patient.
    • Confirm the chest tube is functioning and connected properly.
    • Check suction setting and confirm it matches orders.
    • Look for air leaks by observing bubbles in the water seal chamber and differentiate new vs. pre-existing leaks.
    • Determine whether suction is continuous or if patient can be off suction as ordered.
    • Determine whether the CDU is connected to gravity if suction is off.
    • Monitor drainage volume and rate; measure and document drainage.
    • Identify any pneumothorax on chest radiographs if indicated.

Takeaways: CDU Management and Patient Care

  • Understand the type of CDU in use and its purpose for the patient’s chest tube.
  • Regular assessment of suction and drainage ensures effective pleural space management and early detection of problems.
  • Promptly identify leaks and changes in drainage that may indicate complication.
  • Maintain patient stability during suction adjustments and modality changes.