CPAP Respiratory Therapy
CPAP Overview
Applies continuous pressure to airways to improve oxygenation.
Bridge device to improve oxygenation until underlying cause of the respiratory
distress can be treated.
Primary goal of CPAP
The primary goal of CPAP is to decrease the work of breathing so the patient
doesn’t deteriorate, doesn’t require intubation—which is associated with
increased mortality—and doesn’t suffer respiratory arrest.
C-PAP vs. PEEP
C-PAP non-invasive
PEEP for intubated patients
Terms used interchangeably
Control of breathing
C2 level in the arterial blood
Hypoxic drive
Gas Exchange
Ventilation-allow oxygen to move from the air into the venous blood and carbon
dioxide to move out.
Diffusion-Blood carries oxygen, carbon dioxide, and hydrogen ions between
tissues and the lungs. The majority of CO2 transported in the blood is dissolved in
plasma
Perfusion-blood flow through the pulmonary arterioles.
Congestive Heart Failure
The primary cause of respiratory distress with heart failure is increased work of
breathing.
In heart failure, the heart cannot efficiently pump the blood delivered to it.
The role of CPAP in the treatment of heart failure is twofold
1. The PEEP helps keep the alveoli open during exhalation, and inspiratory
pressure helps to open additional alveoli, relieving the work of breathing;
2. The pressure generated by CPAP helps move fluid back into the vascular
system.
COPD
Chronic Obstructive Pulmonary Disease
Emphysema
Chronic Bronchitis
Asthma
Emphysema
Loss of elasticity of lung tissue
Difficulty exhaling
Air trapping
CO2 retention
Break down of
alveolar walls
Decrease surface area for gas exchange
Chronic Bronchitis
Chronic Inflammation of bronchiole tree with increased mucous production
Difficulty exhaling
– Air trapping
– CO2 retention
Asthma
Intermittent Bronchoconstriction
Difficulty exhaling
– Air trapping
– CO2 retention
Physiological Benefits of C-PAP
Increase in alveolar pressure
– Stop fluid movement into alveoli
– Improves gas distribution
– Prevents alveolar collapse
– Improves re-expansion of alveoli
Reduces work of breathing
Reduces respiratory muscle fatigue
Increases intrathoracic pressure
– Improves cardiac output to a point
– Too much PEEP decreases cardiac output
Decreases need for intubation and associated complications
Hazards/Complications of C-PAP
Airway
– Mask impairs access to patient’s airway
– C-PAP does not ventilate the patient
– Gastric distension / vomiting
• Aerophagia (swallowing air) sensitive patients
– Gastric stapling
– Upper GI surgery
Hypoxia
– Loss of oxygen supply
• Empty oxygen tank
• Disconnection of Oxy-PEEP from oxygen source
– Mask Leak
– Rebound hypoxia may be more severe than initial hypoxia
Hypotension
– Increased intrathoracic pressure causes
• Decreased venous return
• Decreased cardiac output
– Increased pulmonary pressure causes
Decreased blood flow through pulmonary vessels
•Decreased cardiac output
Patient Discomfort
– Requires patient cooperation to tolerate a tightly fitting mask
• Sensation of smothering or claustrophobia
– Use trial to introduce patient to device prior to securing head strap
– Consider sedation for extreme anxiety with orders from Medical Control (ALS)
Procedure
Prepare Patient
– Position Stretcher at 45 degrees or higher
– Inform patient of procedure
Mask Application
– Trial to introduce device
• Explain patient will feel positive oxygen pressure
– Hold mask gently on patient’s face ensuring good seal
– Once patient accepts mask, secure mask with straps
– Deflate mask as needed to get good seal
On-Going Care / Monitoring
– Reassess at least every 5 minutes
• Patient’s impression of difficulty breathing
• Vital signs
• Lung sounds
• SpO2
– Observe for complications
• Hypotension
• Barotrauma
• Worsening dyspnea
If patient continues to have severe difficulty breathing after 5 minutes, consider
increasing PEEP to 10 cm H2O
– Systolic BP must be at least 90 mmHg
– CAREFULLY watch for complications of increased PEEP
Discontinuing CPAP
C-PAP usually is not discontinued in the field
High PEEP level may require weaning
Rebound hypoxia can be worse than initial hypoxia