Transcript
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.
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
Functional Residual Capacity
Lung volume at end of normal exhalation
Muscles of respiration are completely relaxed
http://www.lakesidepress.com/pulmonary/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
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 WheezingCoughingShortness of breathDifficulty breathingChest tightness
Face - itchiness, redness, swelling of face & tongueAirway – trouble breathing, swallowing or speakingStomach – abdominal pain, vomiting, diarrheaTotal 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
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
Summary
Pre-hospital studies have proven the effectiveness of CPAP in treating patients with severe respiratory distress, regardless of disease process.
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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