8Physiology ReviewVentilation- 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.
9Physiology ReviewRespiration- the exchange of oxygen and carbon dioxide between the atmosphere and the body cells-Occurs at the alveolar level
10DiffusionDiffusion – the movement of gas from an area of higher concentration to an area of lower concentration.This is how respiration occurs
11DiffusionIn 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 fluid
12Pulmonary PerfusionPulmonary 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)
13What do we use CPAP for?AsthmaCOPDCHF/Pulmonary Edema
14Asthma A chronic inflammation disorder in the airways Acute episodes “triggered” by somethingThis releases histamine and leukotrienes causingBronchial smooth muscle constrictionBronchial plugging from mucous secretionInflammation changes
15Asthma Leads to increased resistance to airflow Leading to hypoxemia and CO2 retention which leads to hyperventilation and respiratory fatigue
16Asthma Pt. Presentation Tripod positionWheezingA silent chest is an ominous sound!Flow rates are to low to generate breath soundsInability to speakPulse > 130Respirations > 30
17Asthma- Differential Diagnosis Consider other causes for wheezingPneumoniaCOPDForeign body aspirationHeart failurePneumothoraxPulmonary embolismToxic inhalation
19BronchitisInflammation 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 alveoli
20Bronchitis Pt. Presentation History of respiratory infectionProductive coughLarge quantity of sputumShort of BreathCyanosis
21Bronchitis Pt. Presentation MucousAir comes in , but can’t get out
22Bronchitis “Blue Bloater” A productive cough 3 months of the year for 2 consecutive years
23Emphysema Chronic disease Results in destruction and loss of elasticity of the alveolar wallsCaused by:Cigarette smokingExposure to unfriendly environment (ie: asbestos)
24Emphysema Pt. Presentation SkinnyShort of breath all the timeShortness of breath worsens with any activityBarrel chestLong expiratory phase- pursed lipsPink in color (polycythemia)
26Congestive Heart Failure (CHF) Left ventricle unable to emptyLeads to increased pressure in left atriaCauses increased pulmonary pressures which leads to fluid collecting in the lungs
27CHF Pt. Prsentation Respiratory distress Orthopnea Must sit or stand to breath comfortablySpasmodic coughing (pink frothy sputum)Paroxysmal Nocturnal DyspneaApprehension (smothering feeling)CyanosisDiaphoresisRales, possible wheezingJVD
28CHF Pt. Presentation Vitals Increased B/P early (180’s/90’s) Decreased B/P later as patient tiresTachycardiaIncreased respiratory rate early (high 30’s)Decreased respiratory rate as patient tires
32How PEEP is Measured PEEP is measured in cm of water We 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.
337.5 PEEP Used for COPD and Asthma The 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.
3410 PEEPUsed 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 system
35How 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 oxygenFiO2 ~30%
37Physiology of PEEPIt 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.
38Physiology 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 bloodEven this small change in partial pressure is enough to make a clinical difference
39Goals of CPAPChange 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.
40IndicationsHypoxemia with signs and symptoms of COPD, CHF(pulmonary edema), or AsthmaPt. must be breathing and able to protect their airway.
41Contraindications Penetrating Chest Trauma Severe Hypotension Persistent Nausea and/or VomitingObtundationRespiratory or Cardiac ArrestInability to Protect their own Airway
42Application of CPAPHands on demonstration of the application of CPAP to follow at a later date.
43ReferencesInformation for this PowerPoint presentation was obtained from:LEMS Clinical Care GuidelinesCharlottesville Albemarle Rescue Squad