Pre-Hospital Treatment Using the Respironics Whisperflow CPAP Pre-Hospital Treatment Using the Respironics Whisperflow

CPAP-What is it? CPAP is an acronym for: Continuous Positive Airway Pressure

Anatomy Review

Anatomy Review

Alveoli

Chest Wall

Normal Respiration

Physiology Review Ventilation- The mechanical exchange of air between the lungs and the atmosphere. Pulmonary ventilation refers to the total exchange of gas. Alveolar ventilation refers only to the effective ventilation within the alveoli.

Physiology Review Respiration- the exchange of oxygen and carbon dioxide between the atmosphere and the body cells -Occurs at the alveolar level

Diffusion Diffusion – the movement of gas from an area of higher concentration to an area of lower concentration. This is how respiration occurs

Diffusion In order for respiration to take place and be efficient you must have: Functional alveoli and capillary walls An interstitial space between the alveoli and the capillary wall that is not enlarged or filled with fluid

Pulmonary Perfusion Pulmonary perfusion- the process of circulating blood through the pulmonary capillary bed, in order for this to occur you must have: A properly functioning heart (Pump) Proper vascular size (Tank) Adequate blood volume / hemoglobin (fluid)

What do we use CPAP for? Asthma COPD CHF/Pulmonary Edema

Asthma A chronic inflammation disorder in the airways Acute episodes “triggered” by something This releases histamine and leukotrienes causing Bronchial smooth muscle constriction Bronchial plugging from mucous secretion Inflammation changes

Asthma Leads to increased resistance to airflow Leading to hypoxemia and CO2 retention which leads to hyperventilation and respiratory fatigue

Asthma Pt. Presentation Tripod position Wheezing A silent chest is an ominous sound! Flow rates are to low to generate breath sounds Inability to speak Pulse > 130 Respirations > 30

Asthma- Differential Diagnosis Consider other causes for wheezing Pneumonia COPD Foreign body aspiration Heart failure Pneumothorax Pulmonary embolism Toxic inhalation

COPD Chronic Obstructive Pulmonary Disease Chronic Bronchitis Emphysema

Bronchitis Inflammation of the bronchioles with large amounts of sputum present Mucous obstructions Leads to gas trapping Leads to hyper inflation Leads to permanent damage Short of breath due to mucous in alveoli

Bronchitis Pt. Presentation History of respiratory infection Productive cough Large quantity of sputum Short of Breath Cyanosis

Bronchitis Pt. Presentation Mucous Air comes in , but can’t get out

Bronchitis “Blue Bloater” A productive cough 3 months of the year for 2 consecutive years

Emphysema Chronic disease Results in destruction and loss of elasticity of the alveolar walls Caused by: Cigarette smoking Exposure to unfriendly environment (ie: asbestos)

Emphysema Pt. Presentation Skinny Short of breath all the time Shortness of breath worsens with any activity Barrel chest Long expiratory phase- pursed lips Pink in color (polycythemia)

Emphysema- “Pink Puffer”

Congestive Heart Failure (CHF) Left ventricle unable to empty Leads to increased pressure in left atria Causes increased pulmonary pressures which leads to fluid collecting in the lungs

CHF Pt. Prsentation Respiratory distress Orthopnea Must sit or stand to breath comfortably Spasmodic coughing (pink frothy sputum) Paroxysmal Nocturnal Dyspnea Apprehension (smothering feeling) Cyanosis Diaphoresis Rales, possible wheezing JVD

CHF Pt. Presentation Vitals Increased B/P early (180’s/90’s) Decreased B/P later as patient tires Tachycardia Increased respiratory rate early (high 30’s) Decreased respiratory rate as patient tires

Respironics Whisperflow CPAP

Whisperflow Kit Contents Mask and head strap Air filter Hose PEEP valves are separate

PEEP Positive End Expiratory Pressure

How PEEP is Measured PEEP is measured in cm of water We use two different PEEP valves 7.5 (yellow) for COPD and asthma 10 (green) for CHF/Pulmonary Edema If a pt. has a Hx. of COPD the 7.5 is used even if treating the pt. for CHF.

7.5 PEEP Used for COPD and Asthma The lower pressure prevents alveolar damage to COPD pts. due to the loss of elasticity in the alveoli If the 10 peep was used it could cause destruction of alveoli which would be detrimental to the pt.

10 PEEP Used for the treatment of CHF with pulmonary edema with no hx. of COPD The higher pressure allows the fluid in the lungs to be returned to the circulatory system

How it works-Mechanically Causes Venturi effect-Can generate large flows (140 L/min) with relatively little oxygen use. Mixes large quantities of ambient air with a little supplemental oxygen FiO2 ~30%

Oxygen Consumption

Physiology of PEEP It changes the partial pressure of oxygen in the blood Deoxygenated blood has a lower partial pressure of oxygen than alveolar air so oxygen transfers from the air into the blood.

Physiology of PEEP (cont.) 7.5 cm/H2O CPAP increases the partial pressure of alveolar air by approximately 1% This increase in partial pressure ‘forces’ more oxygen into the blood Even this small change in partial pressure is enough to make a clinical difference

Goals of CPAP Change the pressure gradient to force more oxygen into the blood Maintain positive pressure in the lungs to force fluid out. Prevents complete collapse of alveoli during exhalation allowing greater surface area for improved gas exchange.

Indications Hypoxemia with signs and symptoms of COPD, CHF(pulmonary edema), or Asthma Pt. must be breathing and able to protect their airway.

Contraindications Penetrating Chest Trauma Severe Hypotension Persistent Nausea and/or Vomiting Obtundation Respiratory or Cardiac Arrest Inability to Protect their own Airway

Application of CPAP Hands on demonstration of the application of CPAP to follow at a later date.

References Information for this PowerPoint presentation was obtained from: LEMS Clinical Care Guidelines Charlottesville Albemarle Rescue Squad