Gold Cross Ambulance

Continuous Positive Airway Pressure(CPAP)

Airway Endorsement for EMT-Basic

Sheridan Memorial Hospital

Ruth Wyckoff, M.D.

21 January 2012

Outline1. Definition

2. Goals

3. Physiological effects

4. Delivery systems

5. Applications

6. Contraindications

7. Complications

Definition

• Pressurized method of noninvasive ventilation with or without mechanical assistance.

Goals

• Reduce pre-hospital intubations

• Increase functional residual capacity (FRC)

• Provide a stable airway pressure

• Decrease work of breathing (WOB)

Lung and Aveoli

Functional Residual Capacity (FRC)

• Definition: Volume of gas remaining in lungs after expiration

• CPAP prevents alveolar collapse on expiration

• Greater surface area improves gas exchange

Partial Pressure•The pressure of a gas mixture is equal to the sum of the partial pressures of its constituents.

•This allows oxygen into the blood during inspiration and CO2 out during expiration.

•Example : Air at sea level has a pressure of 1000cm H20.

•Air is 21% oxygen and 79% nitrogen and other gasses.

•partial pressure of oxygen is 1000 X 21% = 210cm H20

So why does oxygen pass into the blood?

Pressure Gradient

Deoxygenated blood has a lower partial pressure of oxygen than alveolar air so oxygen transfers from the air into the blood.

CPAP and Patient Airway Pressure

‘The application of positive airway pressure throughout the whole

respiratory cycle to spontaneously breathing patients.

7.5cm H20 CPAP•Atmospheric pressure can be expressed as 1000cm H2O

•7.5cm H2O CPAP increases the pressure of the alveolar air by approximately 1%.

•This increase in partial pressure ‘forces’ more oxygen into the blood.

•Even this comparatively small change is enough to make a clinical difference as CPAP alters the pressure gradient

ARDS

• CPAP overcomes inspiratory work imposed by auto-peep

• CPAP prevents airway collapse during exhalation

• CPAP improves arterial blood gas values

• CPAP may avoid intubation and mechanical ventilation (Miro 1993)

X-ray ARDS

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Reducing fluid in the lungs

• CPAP decreases intra-alveolar fluid volume• Facilitates movement of water

• Move from less to more compliant• Improves oxygenation, compliance

Redistribution of extravascular pulmonary

fluid

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Pneumonia

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Congestive Heart Failure (CHF)

• Definition: Interstitial fluid interferes with gas exchange = pulmonary edema • Increased myocardial workload• Higher O2 demands

Over age of 65 - 10/1000 patientAverage length of stay (LOS) = 6.7 daysThose intubated extend LOSIntubated pts have 4x mortality

Pulmonary Edema

Radiographic evidence

COPD and Asthma

• Both with increased WOB• Hypercapnia• Higher mortality with intubation• Difficulity to wean once intubated

Acute Respiratory Distress Syndrome (ARDS)

• Characteristics• Hypoxemia• Reduced compliance• Large intrapulmonary shunt

• CPAP in early stages may • Correct hypoxemia• Improve compliance• Reduce intrapulmonary shunt• (Schmidt 1975)

Essential Components Of A CPAP System

1. Flow generator

2. CPAP valve

Whisperflow Flow Generators

Caradyne Isobaric CPAP Valve

Patient Connections - Face Mask

The High Flow System In Operation

Air Supply In

Total Flow 60 L/min

Application of CPAP

Application Continued

CPAP System

Clinical Applications of CPAP

Condition Area for TreatmentARDS EmergencyCHF/Pulmonary edema EmergencyAcute Respiratory Failure EmergencyCOPD/Asthma EmergencyAnesthesia Pre OperativeAtelectasis ICU/General WardAlternative to Mechanical Ventilation ICU/General WardWeaning from Mechanical Ventilation ICU/General WardSleep Apnea Home

Contraindications

• Relative• Claustrophobia• Nasal Congestion• Mouth breathing

• Absolute• Cardiac/resp arrest• Hypotension• Need for emergent airway• Pneumothorax• Facial or neurological

injuries, deformities• Upper airway obstruction• High risk of aspiration• Unconscious

Common Complications With CPAP

• Irritation to skin and eyes • Nasal congestion• Dry nose, epistaxis• Sore throat• Barotrauma• Gastric distention• Reduced cardiac output• Hypoventilation

CPAP Training Flow Sheet

2 or more of the following Respiratory Distress Inclusion Criteria

-Retractions of accessory muscles-Brochospasm or Rales on Exam

-Respiratory Rate > 25/min.-O2 Sat. < 92% on high flow O2

Administer CPAP using Max FIO2

-Continue CPAP-Continue COPD/Asthma/Pulmonary Edema Protocol

-Contact Medical Control with a Report

-Contact Medical Control with report-Discontinue CPAP unless advised by Medical Control-Continue Asthma/COPD/Pulmonary Edema Protocols

Stable or Improving Reassess Patient Deteriorating

No Exclusion Criteria Present

-Respiratory/Cardiac Arrest-Pt.unable to follow commands

-Unable tp maintain patent airway independently-Major Trauma

-Suspicion of a Pneumothorax-Vomiting or Active GI Bleed

-Obvious signs/Symptoms of Pulmonary infection

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Supporting Literature• JAMA December 28, 2005 “Noninvasive Ventilation

in Acute Cardiogenic Edema”, Massip et. al.• Meta-analysis with good to excellent data• 45% reduction in mortality• 60% reduction in need to intubate

• Kosowsky JM, et al. EMS transports for difficulty breathing: is there potential role for CPAP in prehospital setting?. Acad Emerg Med. 2000 Oct; 7(10) 1165.• Strict criteria but demonstrated small number of pts

benefit

Cont’d Literature

Reviews in Cardiovascular Medicine, vol. 3 supl. 4 2002, “Role of Noninvasive Ventilation in the Management of Acutely Decompensated Heart Failure”

“Though BLPAP has theoretical advantages over CPAP, there are questions regarding its safety in a setting of CHF. The Key to success in using NIV to treat severe CHF is proper patient selection, close patient monitoring, proper application of the technology, and objective therapeutic goals. When used appropriately, NIV can be a useful adjunct in the treatment of a subset of patients with acute CHF at risk for endotracheal intubation.”