CPAP Respiratory therapy EMT-B

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  CO2 Level in 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 CO 2 transported in the blood is dissolved in plasma  Perfusion-blood flow through the pulmonary arterioles.

Ventilation

Diffusion

Perfusion

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.

Congestive Heart Failure  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.

Congestive Heart Failure  Pulmonary edema washes out surfactant  – Increased work of breathing to maintain open alveoli

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

Physiological Benefits of C-PAP  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

Hazards/Complications of C-PAP  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

Hazards/Complications of C-PAP  Hypotension  – Increased intrathoracic pressure causes  Decreased venous return  Decreased cardiac output  – Increased pulmonary pressure causes  Decreased blood flow through pulmonary vessels  Decreased cardiac output

Hazards/Complications of C-PAP  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

Procedure  Prepare Patient  – Position Stretcher at 45 degrees or higher  – Inform patient of procedure

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

Procedure  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

Procedure  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 C-PAP  C-PAP usually is not discontinued in the field High PEEP level may require weaning  Rebound hypoxia can be worse than initial hypoxia