02.05 Nursing Care and Pathophysiology of Acute Respiratory Distress Syndrome (ARDS)

Overview

Acute Respiratory Distress Syndrome

1. Causes – anything causing inflammatory response in lungs
   1. Bacteremia, Sepsis
   2. Trauma, fat embolus
   3. Burns + Fluid Resuscitation
   4. Massive transfusion
   5. Pneumonia, Aspiration
   6. Drug overdose
   7. Near drowning

Pathophysiology: There are 4 phases within acute respiratory distress syndrome (ARDS). ARDS occurs rapidly and usually within 90 minutes of the body’s inflammatory response and between 24-48 hours of lung injury. In phase 1 there is an injury to the capillary endothelium of the pulmonary system. In phase 2 there is an injury to the basement membrane, interstitial space, alveolar epithelium. The damage to the lungs causes permeability so now fluid fills the alveoli (where it doesn’t belong) and this will impair gas exchange. In phase 3 there is damage to the alveoli because of the fluid that causes atelectasis and hypoxemia. In phase 4 the products of cell damage cause the formation of a hyaline membrane. This membrane is thick and will further prevent oxygen exchange. In this phase with impaired gas exchange, respiratory acidosis occurs. The damage to the lungs that occurs can not be reversed.
Nursing Points

General

1. Inflammatory Response
   1. Cytokines
      1. Alveolar damage
      2. Scarring
      3. Decreases lung compliance
   2. Increased capillary permeability
      1. “Floods” alveoli
      2. Decreases gas exchange
2. Early recognition improves survival

Assessment

1. Symptoms of underlying condition
2. Chest X-ray → diffuse bilateral infiltrates
   1. “White Out”
3. Refractory Hypoxemia
   1. P/F Ratio (PaO2 / FiO2)
   2. Mild  <300
   3. Moderate <200
   4. Severe <100

Therapeutic Management

1. Treat underlying cause
2. Ventilatory Support
   1. High levels of PEEP
   2. Prone position – improve flow into lungs
   3. Special Vent Modes
      1. APRV
      2. Oscillator
3. Prevent Complications
   1. O2 toxicity – keep sats 85-90%
   2. Ventilator Acquired Pneumonia – prevent infection
   3. Barotrauma – keep volumes 4-6 mL/kg
      1. Damage caused by too much pressure in noncompliant lung

Nursing Concepts

1. Oxygenation
2. Gas Exchange
3. Infection Control

Patient Education

1. Educate family on severity of condition and probable course
2. Possible need for tracheostomy
3. Purpose for endotracheal tube and ventilator
4. Recovery time, may need rehab
5. Infection control precautions