CPAPCPAP(Continuous Positive Airway (Continuous Positive Airway

Pressure)Pressure)

Cardiogenic Pulmonary Cardiogenic Pulmonary EdemaEdema

Case StudyCase Study

• Call to residence @ 2146Call to residence @ 2146

• 76 y/o male, SOB76 y/o male, SOB

• On arrival:On arrival:•Pt. seated upright in living roomPt. seated upright in living room

•Conscious, obvious resp. distress, agitatedConscious, obvious resp. distress, agitated

•Pale, diaphoretic, clammy, audibly Pale, diaphoretic, clammy, audibly congestedcongested

• Assessment/Questions/Initial Tx ?Assessment/Questions/Initial Tx ?

Case Study (cont’d)Case Study (cont’d)

• Incident Hx; at rest, abrupt onset, Incident Hx; at rest, abrupt onset, now worsenow worse

• PMHx; MI, CHF/Pulm. Edema, HPT, PMHx; MI, CHF/Pulm. Edema, HPT, AAA repair, Renal Tumor, RxAAA repair, Renal Tumor, Rx

• Presentation; sitting upright, Presentation; sitting upright, tachypneic, 1-2 word dyspnea, tachypneic, 1-2 word dyspnea, ↓↓A/E A/E bil. with coarse crackles throughout, bil. with coarse crackles throughout, now RSCPnow RSCP

Case Study (cont’d)Case Study (cont’d)

• Vitals; P 60, Irr, R 36-40, B/P 200/94, Vitals; P 60, Irr, R 36-40, B/P 200/94, SpO2 76 RA, Skin-Pale/Dia. +++/CoolSpO2 76 RA, Skin-Pale/Dia. +++/Cool

• Monitor; Sinus with PVC’s, 12-lead Monitor; Sinus with PVC’s, 12-lead neg.neg.

• Any other questions/info req’d?Any other questions/info req’d?

• Tx?Tx?

Case Study (cont’d)Case Study (cont’d)

• O2 - Device, FiO2?O2 - Device, FiO2?

• Position? Why?Position? Why?

• Rx – Drug(s) of Rx – Drug(s) of choice/availability/benefitchoice/availability/benefit

• DirectiveDirective

• Goals of Tx?Goals of Tx?

Case Study (cont’d)Case Study (cont’d)

• Current options to improve Current options to improve oxygenation/ventilation?oxygenation/ventilation?

• NRB mask - benefits/limitationsNRB mask - benefits/limitations

• BVM - benefits/limitationsBVM - benefits/limitations

• ETT - benefits/limitationsETT - benefits/limitations

• Other options?Other options?

DefinitionsDefinitions

• CHF - inability of heart to maintain CHF - inability of heart to maintain forward circulation of blood. forward circulation of blood.

• Most severe manifestation; Most severe manifestation; pulmonary edemapulmonary edema

• Pulmonary Edema - extravasation of Pulmonary Edema - extravasation of fluid from pulmonary vasculature to fluid from pulmonary vasculature to interstitium/alveoli of lungsinterstitium/alveoli of lungs

Pathophysiological Pathophysiological MechanismsMechanisms

• Imbalance of Starling forcesImbalance of Starling forces

• Damage to Alveolar/Capillary barrierDamage to Alveolar/Capillary barrier

• Lymphatic obstruction/dysfunctionLymphatic obstruction/dysfunction

• IdiopathicIdiopathic

Cardiogenic Pulmonary Cardiogenic Pulmonary EdemaEdema

• Normal fluid shift/removal:Normal fluid shift/removal:•Opposing forces of plasma oncotic pressure Opposing forces of plasma oncotic pressure

and pulmonary capillary hydrostatic pressureand pulmonary capillary hydrostatic pressure

•Lymphatics remove excessLymphatics remove excess

• Abnormal:Abnormal:•Volume in pulmonary veins/left atrial venous Volume in pulmonary veins/left atrial venous

return exceeds left ventricular outputreturn exceeds left ventricular output

•↑↑pulmonary venous pressurepulmonary venous pressure

•↑↑capillary hydrostatic pressurecapillary hydrostatic pressure

Pulmonary Edema (cont’d)Pulmonary Edema (cont’d)

• Pulmonary capillary pressure Pulmonary capillary pressure exceeds plasma colloidal osmotic exceeds plasma colloidal osmotic pressurepressure

•(Norm. PCWP 8-12 mmHg, Normal Colloidal (Norm. PCWP 8-12 mmHg, Normal Colloidal Osmotic Pressure 25-28 mmHg)Osmotic Pressure 25-28 mmHg)

• Fluid shifts to interstitiumFluid shifts to interstitium

• Lymphatic removal does not increase Lymphatic removal does not increase in proportion to fluid accumulationin proportion to fluid accumulation

Pulmonary Edema (cont’d)Pulmonary Edema (cont’d)

• Stages:Stages:•↑↑Lt. atrial pressure opens/distends small Lt. atrial pressure opens/distends small

pulmonary vesselspulmonary vessels

•Fluid/colloids shift to interstitiumFluid/colloids shift to interstitium

•Continual filtration overwhelms lymphaticsContinual filtration overwhelms lymphatics

•Fluid accumulates/surround Fluid accumulates/surround alveoli/bronchioles (compromises small alveoli/bronchioles (compromises small airways first)airways first)

• Increases space between capillaries/alveoliIncreases space between capillaries/alveoli

•Disrupts alveolar membrane-floods alveoliDisrupts alveolar membrane-floods alveoli

Pulmonary Edema (cont’d)Pulmonary Edema (cont’d)

• Effects:Effects:– Decreases vital capacityDecreases vital capacity– Causes abnormalities in gas exchangeCauses abnormalities in gas exchange– Decreases respiratory volumeDecreases respiratory volume– Leads to hypoxemiaLeads to hypoxemia

Pulmonary Edema (cont’d)Pulmonary Edema (cont’d)

• Vicious cycle ensues:Vicious cycle ensues:•↓↓CO stimulates sympathetic activityCO stimulates sympathetic activity

•Renin-Angiotensin-Aldosterone systemRenin-Angiotensin-Aldosterone system

•Catecholamine production:Catecholamine production:– ↑ ↑ PVRPVR– ↑↑ MVO2MVO2– exacerbates myocardial ischemiaexacerbates myocardial ischemia– ↓↓ LV filling/emptying/functionLV filling/emptying/function– Further Further ↑ ↑ pulmonary capillary hydrostatic pressurepulmonary capillary hydrostatic pressure– More fluid shiftMore fluid shift

Pulmonary Edema (cont’d)Pulmonary Edema (cont’d)

• Cardiac causes:Cardiac causes:•CADCAD

•Loss of LV muscle/functionLoss of LV muscle/function

•Valvular heart diseaseValvular heart disease

•Decreased diastolic ventricular complianceDecreased diastolic ventricular compliance

•Congenital heart diseaseCongenital heart disease

•MyocarditisMyocarditis

• Infectious endocarditisInfectious endocarditis

•↑ ↑ B/PB/P

Pulmonary Edema (cont’d)Pulmonary Edema (cont’d)

• Precipitated by:Precipitated by:• IschemiaIschemia• DysrhythmiaDysrhythmia• Cardiac/extra cardiac infectionCardiac/extra cardiac infection• P.E.P.E.• Physical/environmental stressPhysical/environmental stress• Non-compliance/changes to RxNon-compliance/changes to Rx• Dietary changesDietary changes• Iatrogenic volume overloadIatrogenic volume overload• PregnancyPregnancy• HyperthyroidismHyperthyroidism

DifferentialsDifferentials• ARDSARDS• AnaphylaxisAnaphylaxis• Acute anemiaAcute anemia• BronchitisBronchitis• COPDCOPD• MyopathiesMyopathies• PneumoniaPneumonia• PneumoPneumo• Shock (septic)Shock (septic)• P.E.P.E.

TreatmentTreatment

• ABC’sABC’s• Improve oxygenation/ventilationImprove oxygenation/ventilation•O2 to keep SpO2 O2 to keep SpO2 > 90%> 90%•Assist ventilations or provide non-invasive Assist ventilations or provide non-invasive

positive pressure ventilationpositive pressure ventilation

• 3 Goals:3 Goals:•↓↓ PreloadPreload•↓↓ AfterloadAfterload• Inotropic supportInotropic support

Treatment (cont’d)Treatment (cont’d)

• Preload reduction:Preload reduction:•↓↓’’s pulmonary capillary hydrostatic pressures pulmonary capillary hydrostatic pressure•↓↓’’s rate of fluid shifts rate of fluid shift

• Afterload reduction:Afterload reduction:•↑↑’’s COs CO•↑↑’’s Renal perfusions Renal perfusion

• Inotropic support:Inotropic support:•For those that won’t tolerate For those that won’t tolerate

preload/afterload reduction 2º to hypotensionpreload/afterload reduction 2º to hypotension

NitroglycerinNitroglycerin

• VasodilatorVasodilator• Used with normotensive/hypertensive Used with normotensive/hypertensive

patientspatients• Most effective, predictable and rapid-Most effective, predictable and rapid-

acting Rx available for preload acting Rx available for preload reductionreduction

• Often occurs within 5 min.Often occurs within 5 min.• Usually with some afterload reduction Usually with some afterload reduction

as wellas well

Nitroglycerine (cont’d)Nitroglycerine (cont’d)

• ↓↓’’s MVO2 by s MVO2 by ↓↓’ng workload’ng workload• ↑↑’’s coronary blood flows coronary blood flow• ↑↑’’s forward blood flows forward blood flow• ↓↓’’s pulmonary hydrostatic s pulmonary hydrostatic

pressure/pulmonary congestionpressure/pulmonary congestion• SL spray:SL spray:

•Onset 1-3 min.Onset 1-3 min.•Half-life 5 min.Half-life 5 min.

Furosemide Furosemide (Peterborough Region Only)(Peterborough Region Only)

• Long-standing mainstay of therapyLong-standing mainstay of therapy• Thought to have two physiological Thought to have two physiological

effects:effects:• Immediate venodilationImmediate venodilation•Diuretic affectDiuretic affect

• May in fact be more harmful than May in fact be more harmful than beneficialbeneficial

• Move away from use in many Move away from use in many prehospital servicesprehospital services

Morphine Morphine (Peterborough Region Only)(Peterborough Region Only)

• Third drug in “classic” treatmentThird drug in “classic” treatment• Again, thought to have two major benefits:Again, thought to have two major benefits:

• Preload/Afterload reduction through vasodilationPreload/Afterload reduction through vasodilation• Anxiolytic/Analgesic effectsAnxiolytic/Analgesic effects

• No sound evidence supports morphine-No sound evidence supports morphine-mediated preload reductionmediated preload reduction

• Recent studies show morphine use an Recent studies show morphine use an independent predictor of mortalityindependent predictor of mortality

• Use has declined both in-hospital and Use has declined both in-hospital and prehospitalprehospital

Non-invasive VentilationNon-invasive Ventilation

• Delivery of ventilatory support without Delivery of ventilatory support without need of invasive artificial airwayneed of invasive artificial airway

• Will often eliminate the need for Will often eliminate the need for intubation/tracheostomyintubation/tracheostomy

• Benefits:Benefits:•Easier to wean off ventilatorEasier to wean off ventilator

•Preserves normal cough/swallowing/speech Preserves normal cough/swallowing/speech mechanismsmechanisms

NPPV (cont’d)NPPV (cont’d)

• Two methods:Two methods:•BiPAP (Bilevel Positive Airway Pressure)BiPAP (Bilevel Positive Airway Pressure)

•CPAP (Continuous Positive Airway Pressure) CPAP (Continuous Positive Airway Pressure)

CPAPCPAP

• Delivered by nasal or face maskDelivered by nasal or face mask• Pt. breathes through mask against a Pt. breathes through mask against a

continuous positive a/w pressurecontinuous positive a/w pressure• Can be delivered by either volume or Can be delivered by either volume or

pressure controlled ventilatorpressure controlled ventilator• Delivers set pressure with each Delivers set pressure with each

breath, maintained throughout the breath, maintained throughout the respiratory cyclerespiratory cycle

CPAP (cont’d)CPAP (cont’d)

• Mechanism:Mechanism:• Increases gas exchange 2Increases gas exchange 2º to increased alveolar º to increased alveolar

ventilationventilation

•Prevents alveolar collapse during exhalation by Prevents alveolar collapse during exhalation by maintaining a positive intra-alveolar pressuremaintaining a positive intra-alveolar pressure

•↑↑’’s intrathoracic pressure, reducing s intrathoracic pressure, reducing preload/afterload and improving cardiac outputpreload/afterload and improving cardiac output

CPAP (cont’d)CPAP (cont’d)

• Benefits:Benefits:•Reduces need for intubationReduces need for intubation

•Pt. saves energy otherwise spent trying to Pt. saves energy otherwise spent trying to reopen collapsed alveolireopen collapsed alveoli

•↓↓’ ’ WOB: improves alveolar ventilation while WOB: improves alveolar ventilation while simultaneously resting respiratory musclessimultaneously resting respiratory muscles

•↓↓’’s metabolic rate/substrate need to fuel s metabolic rate/substrate need to fuel respiratory effortrespiratory effort

CPAP (cont’d)CPAP (cont’d)

• Advantages:Advantages:•Avoidance of intubation-related traumaAvoidance of intubation-related trauma

•Decreased incidence of nosocomial Decreased incidence of nosocomial pneumoniapneumonia

•Enhances pt. comfortEnhances pt. comfort

•Shorter duration of ventilator use/facilitates Shorter duration of ventilator use/facilitates weaningweaning

•Decreased hospital stayDecreased hospital stay

•Decreased costsDecreased costs

CPAP (cont’d)CPAP (cont’d)

• Usage:Usage:•Currently utilized primarily in-hospital Currently utilized primarily in-hospital

setting and by critical care EMS systemssetting and by critical care EMS systems•Also used in-homeAlso used in-home•Wide-scale EMS use previously limited by Wide-scale EMS use previously limited by

cost/complexity of technologycost/complexity of technology•Newer technology and sig. reduced costs Newer technology and sig. reduced costs

lend to increased use pre-hospitallend to increased use pre-hospital•Numerous systems incorporating CPAP as Numerous systems incorporating CPAP as

standard for pulmonary edema therapystandard for pulmonary edema therapy