CPAP

CPAPPre-Hospital TreatmentUsing the Respironics Whisperflow

CPAP is an acronym for:

Continuous

Positive

Airway

PressureCPAP-What is it?

Anatomy Review

Anatomy Review

Alveoli

Chest Wall

Normal Respiration

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 levelPhysiology Review

Diffusion the movement of gas from an area of higher concentration to an area of lower concentration.

This is how respiration occursDiffusion

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

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)Pulmonary Perfusion

AsthmaCOPDCHF/Pulmonary EdemaWhat do we use CPAP for?

A chronic inflammation disorder in the airwaysAcute episodes triggered by somethingThis releases histamine and leukotrienes causingBronchial smooth muscle constrictionBronchial plugging from mucous secretionInflammation changesAsthma

Leads to increased resistance to airflowLeading to hypoxemia and CO2 retention which leads to hyperventilation and respiratory fatigueAsthma

Tripod positionWheezingA silent chest is an ominous sound!Flow rates are to low to generate breath soundsInability to speakPulse > 130Respirations > 30Asthma Pt. Presentation

Consider other causes for wheezingPneumoniaCOPDForeign body aspirationHeart failurePneumothoraxPulmonary embolismToxic inhalationAsthma- Differential Diagnosis

COPDChronic Obstructive Pulmonary Disease

Chronic BronchitisEmphysema

Inflammation of the bronchioles with large amounts of sputum presentMucous obstructionsLeads to gas trappingLeads to hyper inflationLeads to permanent damageShort of breath due to mucous in alveoliBronchitis

History of respiratory infectionProductive coughLarge quantity of sputumShort of BreathCyanosisBronchitis Pt. Presentation

Bronchitis Pt. Presentation

MucousAir comes in , but cant get out

A productive cough 3 months of the year for 2 consecutive yearsBronchitis Blue Bloater

Chronic diseaseResults in destruction and loss of elasticity of the alveolar wallsCaused by:Cigarette smokingExposure to unfriendly environment (ie: asbestos)Emphysema

SkinnyShort of breath all the timeShortness of breath worsens with any activityBarrel chestLong expiratory phase- pursed lipsPink in color (polycythemia)

Emphysema Pt. Presentation

Emphysema- Pink Puffer

Left ventricle unable to emptyLeads to increased pressure in left atriaCauses increased pulmonary pressures which leads to fluid collecting in the lungsCongestive Heart Failure (CHF)

Respiratory distressOrthopneaMust sit or stand to breath comfortablySpasmodic coughing (pink frothy sputum)Paroxysmal Nocturnal DyspneaApprehension (smothering feeling)CyanosisDiaphoresisRales, possible wheezingJVDCHF Pt. Prsentation

Vitals

Increased B/P early (180s/90s)Decreased B/P later as patient tiresTachycardiaIncreased respiratory rate early (high 30s)Decreased respiratory rate as patient tiresCHF Pt. Presentation

Respironics Whisperflow CPAP

Mask and head strapAir filterHosePEEP valves are separateWhisperflow Kit Contents

PositiveEndExpiratoryPressurePEEP

PEEP is measured in cm of waterWe use two different PEEP valves7.5 (yellow) for COPD and asthma10 (green) for CHF/Pulmonary EdemaIf a pt. has a Hx. of COPD the 7.5 is used even if treating the pt. for CHF.How PEEP is Measured

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

Used for the treatment of CHF with pulmonary edema with no hx. of COPDThe higher pressure allows the fluid in the lungs to be returned to the circulatory system10 PEEP

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%How it works-Mechanically

Oxygen Consumption

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

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 bloodEven this small change in partial pressure is enough to make a clinical differencePhysiology of PEEP (cont.)

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

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

Penetrating Chest TraumaSevere HypotensionPersistent Nausea and/or VomitingObtundationRespiratory or Cardiac ArrestInability to Protect their own AirwayContraindications

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

Information for this PowerPoint presentation was obtained from:LEMS Clinical Care GuidelinesCharlottesville Albemarle Rescue SquadReferences