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Congestive Heart Failure and Pulmonary Edema Nestor Nestor, MD June 21, 2006 Goals and Outline 1. Pathophysiology of Congestive Heart Failure (CHF) 2. Recognizing CHF and Pulmonary Edema (PE) 3. Prehospital Treatment 1. Pathophysiology Terminology • Heart Failure: The inability of the heart to maintain an output adequate to maintain the metabolic demands of the body. • Pulmonary Edema: An abnormal accumulation of fluid in the lungs. • CHF with Acute Pulmonary Edema: Pulmonary Edema due to Heart Failure (Cardiogenic Pulmonary Edema) The Heart is Two Pumps in Series O2 CO2 LA RV tissue Like any pump: • The heart generates pressure to deliver blood to the body • Therefore it also must… Pull blood out of the veins Fluid (and some cells) from stagnating blood leak out… alveolus capillary lymphatic Three Pathophysiological Causes of Failure • Increased work load (HTN) • Myocardial Dysfunction (ASCVD) • Decreased Ventricular Filling (Valvular, cardiomyopathy, etc.) Normal Heart RV LV Myocardial Infarction Hypertension Dilated Cardiomyopathy Heart Failure - Concepts • Cardiac Output (L/min) • Afterload (BP) – Primarily arterial and systolic function • Preload (volume) – Primarily a venous and diastolic function • Frank-Starling Length: Tension Ratio – Why preload effects output CHF: A Vicious Cycle Low Output Increased Preload Increased Afterload Norepinephrine Increased Salt Vasoconstriction Renin Angiotension I Angiotension II Aldosterone Renal Blood Flow Airway no gas exchange Gas exchange CO2 flow O2 Infiltration of Interstitial Space Normal Micro-anatomy Micro-anatomy with fluid displacement Perivascular cuffs in early pulmonary edema cuff Normal lung Early pulmonary edema The ultimate insult: alveolar flooding flow Precipitating Causes • • • • • • Non-Compliance with Meds and Diet Increased Sodium Diet (Holiday Failure) Acute MI Arrhythmia (e.g. AF) Infection (pneumonia, viral illness) Pregnancy 2. Recognizing CHF and Pulmonary Edema Acute Pulmonary Edema History, History, History • Acute or chronic onset • Prior episodes • Weight gain • Medications Symptoms • Fatigue • GI Symptoms • Nocturia • Chest Pain • DOE • Orthopnea • PND • Profound Dyspnea Vitals • Tachypnic • Tachycardic • Hypoxic • Hypertensive (even “normal” may be too high) • or Hypotensive in severe failure Physical Exam • • • • • • Anxious Pale Clammy Confusion Edema Diaphoretic • • • • • • Rales Rhonchi S3 Gallop JVD Pink Frothy Sputum Cyanosis Pitting Edema JVD 3. Prehospital Treatment EMS Management • • • • • • Sit upright High Flow O2 Nitroglycerine (If SBP > 100) Morphine Diuretics (furosemide) Ventilatory Support – CPAP – BVM – Intubation and ventilation Pharmacological Treatment: Nitroglycerine (NTG) • Relaxes arteries and veins • 0.4 mg sub lingual or 1 spray • Repeat x2 every 5 min if SBP > 100 • Consider 1” NTG paste to CW Pharmacological Treatment: Morphine • Also relaxes arteries and veins • Reduces anxiety and O2 demand • 2-4 mg IV Pharmacological Treatment: Furosemide (Lasix) • A diuretic, reducing fluid overload • Requires good enough cardiac output to reach the kidneys • 40mg IV • May require more if already taking Lasix Pharmacological Treatment: Beta Blockers (Lopressor)??? • Not useful in acute CHF • Decrease HR and output, worsening failure • May cause/worsen bronchoconstriction • However they are used in stable, compensated failure so they may be on a pt’s med list Ventilatory Support: CPAP Continuous Positive Airway Pressure CPAP is oxygen therapy in its most efficient form. Simple Masks Venturi Masks CPAP Why does oxygen pass into the blood? The Pressure Gradient Deoxygenated blood has a lower partial pressure of oxygen so oxygen transfers from the air into the blood. CPAP and Patient Airway Pressure ‘The application of positive airway pressure throughout the whole respiratory cycle to spontaneously breathing patients. CPAP increases the pressure gradient • 7.5cm H2O CPAP increases the partial pressure of the alveolar air by approximately 1%. • This increase in partial pressure ‘forces’ more oxygen into the blood. • Even this comparatively small change is enough to make a clinical difference. Physiological Effects Of CPAP • Increases the volume of gas remaining in lungs at end-expiration • CPAP distends alveoli preventing collapse on expiration • Greater surface area improves gas exchange • Reduces work of breathing Application CPAP And Pulmonary Edema CPAP increases transpulmonary pressure CPAP improves lung compliance CPAP improves arterial blood oxygenation CPAP redistributes extravascular lung water Redistribution Of Extravascular Lung Water With CPAP CPAP And Acute Respiratory Failure CPAP prevents airway collapse during exhalation CPAP overcomes inspiratory work imposed by auto-peep (pursed lip breathing) CPAP may avoid intubation and mechanical ventilation Caution • COPD and Asthmatic patients do not respond predictably to CPAP • Higher risk of complications such as pneumothorax When Not To Use Mask CPAP Pneumothorax (evolve into tension) Hypovolemia (further limit preload) Severe facial injuries Patients at risk of vomiting Common Complications With CPAP Gastric distension Pulmonary barotrauma Reduced cardiac output Hypoventilation CPAP Flow Sheet No Exclusion Criteria Present -Respiratory/Cardiac Arrest -Pt.unable to follow commands -Unable tp maintain patent airway independently -Major Trauma -Suspicion of a Pneumothorax -Vomiting or Active GI Bleed -Obvious signs/Symptoms of Pulmonary infection 2 or more of the following Respiratory Distress Inclusion Criteria -Retractions of accessory muscles -Brochospasm or Rales on Exam -Respiratory Rate > 25/min. -O2 Sat. < 92% on high flow O2 Administer CPAP using Max FIO2 Reassess Patient -Continue CPAP -Continue COPD/Asthma/Pulmonary Edema Protocol -Contact Medical Control with a Report Deteriorating -Contact Medical Control with report -Discontinue CPAP unless advised by Medical Control -Continue Asthma/COPD/Pulmonary Edema Protocols , Stable or Improving Ventilatory Support: Intubation • Definitive (but not first) treatment of pulmonary edema • Positive pressure redistributes edema fluid as in CPAP but to a greater extent • Mechanical ventilation greatly reduces O2 demand • Sedation/paralysis also reduces O2 demand and increases compliance Ultimate Therapies • If pt stabilizes: long term therapy with beta blockers and ACE inhibitors • If cardiac output remains unacceptable: – Beta agonists – LVAD – Transplant In Summary 1. Heart failure is the result of an acute event (MI, AF) or chronic decompensation 2. Pulmonary edema frequently results from cardiac failure but may also result from other disease processes (ARDS) or direct insult 3. Correct diagnosis is crucial and depends on good history and exam 4. Therapy is both pharmacological and ventilatory support Thank You