ACUTE RESPIRATORY DISTRESS SYNDROME (ARDS) – Clinical Manifestations, Pathophysiology, Assessment and Diagnostic Findings and Management
It is the clinical syndrome which is characterized by a sudden and progressive pulmonary edema, increased bilateral infiltrates on chest X-ray, and the absence of an elevated atrial pressure.
Patient often demonstrates reduced lung compliance. A wide range of factors are associated with the development of ARDS. The main cause of death in ARDS is nonpulmonary multiple system organ failure, often with sepsis. Etiological factors related to acute respiratory distress syndrome:
Aspiration (gastric secretion, drowning)
Drug ingestion and overdose
Hematological disorder
Prolonged inhalation of high concentrations of oxygen, smoke and corrosive substance
Major surgery
Fat embolism
Systemic sepsis
Shock, trauma
CLINCIAL MANIFESTATIONS
ARDS is an acute event that typically develops over 4 to 48 hours. The acute phase of ARDS is marked by a rapid onset of severe dyspnea that usually occurs 12 to 48 hours after initiating the event. Other signs and symptoms include:
- Increased pulse rates
- Low PaO2
- Dyspnea
- Marked restlessness
- Decreased mental status
- Tachycardia
- Sudden breathlessness
- Low blood oxygen levels
- Lung inflammation
- Tachypnea
- Hypotension
PATHOPHYSIOLOGY
Acute lung injury —- inflammation and inflammatory response —- release of mediators —- ↑ Capillary membrane, ↓ in airway diameter and injury to pulmonary vasculature
Permeability —- alveolar flooding —- with loss of surfactant —- alveolar collapse
↑ Airway resistance — ↓ Lung compliance —- ↑ work of breathing alveolar hypoventilation —- intrapulmonary shunting hypoxemia
Pulmonary vasoconstriction —- microemboli formation —- pulmonary hypertension alveolar dead space —- ↓ cardiac output
ASSESSMENT AND DIAGNOSTIC FINDINGS
On the physical examination, intercostal retraction and crackles may be present as the fluid begins to leak into the alveolar interstitial space. Common diagnostic tests performed in patient with potential ARDS include:
- Echocardiography
- ABG
- CT scan of thorax
- Chest X-ray
- Sputum culture
- Pulmonary artery catheterization
MANAGEMENT
- The primary focus in the management of ARDS includes identification and treatment of the underlying condition. The supportive therapy almost always includes intubation and mechanical ventilation. In addition, circulatory support, adequate fluid volume, and nutrition support are important.
- Supplement oxygen is used by the patient to begin the initial spiral of hypoxemia. As the hypoxemia progresses intubation and mechanical ventilation are required
TREATMENT OF ARDS
- Intravenous fluids are given to provide nutrition and prevent dehydration and are carefully monitored to prevent fluid from accumulating in lungs
- Antibiotic therapy is provided for infection
Pharmacological Management
In pharmacological management following drugs are included:
- Antianxiety to reduce the anxiety
- Diuretics to eliminate fluid from lungs
- Antibiotics for the infection
- Anti-inflammatory drugs
Nutritional Therapy
Adequate nutritional therapy support is vital in the treatment of ARDS. Patient with ARDS requires 35 to 45 kcal/kg/day to meet caloric requirement. Enteral feeding is the first consideration; however, parental nutrition may also be required.
Complications
- Dysrhythmias
- Multiorgan failure
- Renal failure
- Infection
- Stress ulcer
- Decreased cardiac output
Nursing Management
General Measure
- A patient with ARDS is critically ill and requires close monitoring in the intensive care unit because his/her conditions could quickly become life-threatening. The nurse must closely monitor the patient for deterioration in oxygenation with a change in position. Oxygenation is sometimes increased in the ARDS patient in prone position. The position is elevated for improvement of oxygenation
- A patient is extremely anxious and agitated because of the increase in hypoxemia and dyspnea. It is important to reduce the patient’s anxiety because anxiety increases oxygen expenditure by preventing rest. Rest is essential to limit oxygen consumption and reduce oxygen need.
Nursing Assessment
- Assess breathing sound
- Assess sign of hypoxemia and hypercapnea
- Note the changes suggesting increased work of breathing or pulmonary
- Determine hemodynamic status and compare it with previous value
- Analyze the ABG and improve the previous values
Nursing Diagnosis
- Ineffective airway clearance related to increase or tenacious secretion
- Impaired gas exchange related to inadequate respiratory center activity or chest wall movement, airway obstruction, or fluid in lung
- Acute pain related to inflammatory process of dyspnea
Nursing Intervention
- Maintain airway clearance:
Administer medication to increase alveolar function
Perform chest physiotherapy to remove mucus
Administer IV fluids
Suction patient as needed to assist with removal of secretions
- Relieving pain:
Watch patient for sign of discomfort and pain
Position the head elevated
Give prescribed morphine and monitor for pain-relieving sign
- Reducing anxiety
Correct dyspnea and relive physical discomfort
Speak calmly and slowly
Explain diagnostic procedure
Listen to the patient
