Continuous Positive Airway Pressure

For EMT Providers

State Education & Training CommitteeDecember 2012

Goal

The student will be able to correctly utilize service specific CPAP devices in a respiratory compromised patient

[img]http://hammondems.com/images/d_1976.jpg

Objectives

At the completion of this training, the BLS provider will: Describe respiratory anatomy and physiology Verbalize understanding of respiratory

disorders / illnesses Appreciate the benefits and limitations of

CPAP in alleviating patient symptoms List indication and contraindications for use.

Anatomy and Physiology of Respiration

Respiratory Physiology

Nose / Mouth Trachea Mainstem Bronchi Secondary Bronchi Tertiary Bronchi Bronchioles Terminal Bronchiole Alveoli Diaphragm

http://www.uni.edu/schneidj/webquests/spring04/offtowar/respiratory.html

Negative Pressure

Respiration driven by process of negative intrathoracic pressures Negative pressure

Initiates inhalation and acquisition of O2

Assists to increase intrathoracic blood flow

Hemodynamic Effects

Equalization of pressures initiates exhalation and elimination of CO2

Bronchi / Bronchioles

Cartilage structures give way to smooth muscle

May divide up to 25 times before reaching terminal bronchioles

http//medicalpicturesinfo.com/bronchial-tree/

Alveoli

Expand and contract with breathing Contact with pulmonary capillary beds for gas

exchange Inside surface coated with surfactant

Prevents aveoli from sticking together Keeps alveoli open

Atelectasis

Mechanics of Respiration

http://www.teachpe.com/anatomy/respiratory_system.php

Functional Residual Capacity

Lung volume at end of normal exhalation

Muscles of respiration are completely relaxed

http://www.lakesidepress.com/pulmonary/htm

Gas Exchange

http://www.uic.edu/classes/bios/bios100/lectures/circ.htm

Oxygenation

Process of getting oxygen to end organs and tissues Inhaled through lungs Picked up from alveoli on RBCs Off-loaded in exchange for CO2

Measured by pulse oximetry (SpO2)

Ventilation

Process to eliminate carbon dioxide (waste product of energy production) Carried back through venous blood Eliminated through exhalation

Measured by capnography

Capnography

The capnogram wave form begins before exhalation and ends with inspiration. Exhalation comes before inhalation

http://www.lusotech.com.br/catalogo/continuous-waveform-capnography

Capnography Waveform

http://medicscribe.com/:ffeb_network_search_context=blog/amp;s=pain/management

Respiratory Disorders

Respiratory Disorders

A combination of many disease processes responsible for emergencies related to

ventilation, diffusion and perfusion.

Respiratory Distress

Subjective indication of some degree of difficulty breathing Causes

Upper or lower airway obstruction Inadequate ventilation Impaired respiratory muscle function Impaired nervous system Trauma Bronchitis, pneumonia, cancer

Respiratory Failure

Clinical state of inadequate oxygenation, ventilation or both.

Often end-stage of respiratory distress Signs:

Tachypnea (early) Bradypnea or apnea (late) Increased, decreased, or no respiratory effort Tachycardia (early) Bradycardia (late) Cyanosis Altered Mental Status

Mechanism of Heart Failure

Frequently a chronic, yet manageable condition

Left ventricle fails to work as effective pump Blood volume backs up into pulmonary

circulation Most often caused by:

Volume overload Pressure overload Loss of myocardial tissue Impaired contractility

Pulmonary Edema

Cardiac and respiratory system impairment Acute and critical emergency Filling of lungs with fluid

Washes away surfactant Creates pink froth in sputum

Prevents alveoli from expanding Significantly reduces or eliminates ability for gas

exchange to occur

Asthma

Reactive airway disorder Exacerbation precipitated by extrinsic or

intrinsic factors Characterized by reversible bronchial smooth

muscle contraction, increased mucus production and inflammatory airway changes

Persistent signs and symptoms can indicate a tenfold increase in the work of breathing

Asthma

Evolution of asthma attack Mucus thickens and

accumulates plugging airways

Mucosal edema develops

Muscle spasms constrict small airways

Breathing becomes labored

Exhalation becomes difficult

http://asthma-ppt.com/asthma-pictures.html

Caution

Asthma Anaphylaxis

Causes Smoke, dander, dust, pollen, cold air, mold, cleaning products, perfume, exercise

Nuts, shellfish, milk, eggs, soy, wheat, insect stings, medications, latex

Symptoms Wheezing

Coughing

Shortness of breath

Difficulty breathing

Chest tightness

Face - itchiness, redness, swelling of face & tongue

Airway – trouble breathing, swallowing or speaking

Stomach – abdominal pain, vomiting, diarrhea

Total hives, rash, itchiness, swelling, weakness, pallor, sense of doom, loss of consciousness

Chronic Obstructive Pulmonary Disease

Obstructive lung disease Triad of distinct diseases that often coexist

Asthma Chronic bronchitis Emphysema

Traditionally refers to patients with combination of chronic bronchitis and emphysema

Chronic Bronchitis

Bronchi become filled with excessive mucus Alveoli are not affected Diffusion of gas remains relatively normal

Patients develop low oxygen pressures (PO2) and hypoventilation

Hypoventilation leads to high levels of CO2

and low levels of O2

Emphysema

Results from pathological changes in the lung Permanent abnormal

enlargement of air spaces beyond terminal bronchioles

Collapse of the bronchioles

Destruction of the alveoli

http://health.allrefer.com/health/chronic-obstructive-pulmonary-disease-emphysema.html

Emphysema

Patients have some resistance to airflow, primarily on exhalation Hyper-expansion

caused by air trapped in the alveoli

Breathing becomes an active process

Sanders, M.J. (2005) Paramedic Textbook (3rd ed.) St. Louis: Mosby-Elsevier

Emphysema

Bleb formation

Risk of pneumothorax Interior airway pressure

CO2 Retention Potential worsening with CPAP

ContinuousPositiveAirway

Pressure

The use of CPAP prehospitally reduces the need for intubation by 30% and reduces mortality by 20%

Annals of Emergency Medicine, September 2008

CPAP

Non-invasive ventilation

Continuous O2

delivered at a set positive pressure throughout the respiratory cycle

www.ems1.com/cpap-for-ems

Positive Pressure

PUSHES air into the chest Overcomes airway resistance

Bag valve mask Demand valve Intubation / mechanical ventilation CPAP

Effects of CPAP

Increases functional residual capacity

Increases alveolar surface area available for gas exchange

Increases oxygen diffusion across alveolar membranes

Reduced work of breathing

How CPAP Works

Maintains constant level of airway pressure

Keeps alveoli open (asthma, COPD)

Moves fluid into vasculature (pulmonary edema)

Improves gas exchange

Buys time for medications to work

Indications

Severe Respiratory Distress / Respiratory Failure Accessory muscle use? Persistent hypoxia despite appropriate /

aggressive oxygen therapy? Marked increased work of breathing? Inability to speak full sentences?

Differentiate Pulmonary Edema versus other Respiratory Disorder

Contraindications

Respiratory rate < 10 breaths / minute Systolic blood pressure < 100 mmHg Confusion

Inability to understand directions and cooperate with application of CPAP

History of pneumothorax History of recent tracheo-bronchial surgery

Active nausea or vomiting Despite antiemetic therapy by paramedics

Limitations

CPAP is not a mechanical ventilator

Tight mask seal can create claustrophobic response Consider allowing patient to self-seal (hold

own mask) until initial benefits recognized

CPAP is powered by on-board oxygen supply

Oxygen Utilization

Oxygen Demand

Summary

Pre-hospital studies have proven the effectiveness of CPAP in treating patients with severe respiratory distress, regardless of disease process.

ANY

QUESTIONS

Special Thanks

To:

Peter Canning for time and effort in initial development of program

David Bailey for contributions of supplemental information to enhance presentation

Richard Sanders for development of glossary of terms

Nancy Brunet for final project coordination

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Practical

Skills

Session