CPAP Respiratory Therapy

CPAP Overview

Applies continuous pressure to airwaysto improve oxygenation.

Bridge device to improve oxygenationuntil underlying cause of the respiratorydistress 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 hydrogenions 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

ChronicInflammation ofbronchiole tree withincreased mucousproduction

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 andassociated 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 oxygensource

– Mask Leak

– Rebound hypoxia may be more severethan initial hypoxia

Hypotension

– Increased intrathoracic pressure causes

• Decreased venous return

• Decreased cardiac output

– Increased pulmonary pressure causes

Decreased blood flow through pulmonaryvessels

•Decreased cardiac output

Patient Discomfort

– Requires patient cooperation to tolerate atightly fitting mask

• Sensation of smothering or claustrophobia

– Use trial to introduce patient to device priorto securing head strap

– Consider sedation for extreme anxiety withorders 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 oxygenpressure

– Hold mask gently on patient’s faceensuring good seal

– Once patient accepts mask, secure maskwith 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 severedifficulty breathing after 5 minutes,consider increasing PEEP to 10 cmH2O

– Systolic BP must be at least 90 mmHg

– CAREFULLY watch for complications ofincreased PEEP

Discontinuing CPAP

C-PAP usually is not discontinued in the field

High PEEP level may require weaning

Rebound hypoxia can be worse thaninitial hypoxia