7/12/2014. Cardiovascular Emergencies (Class 11)

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1 Cardiovascular Emergencies (Class 11) Review Circulatory System Anatomy and Physiology Blood flow through the heart Regular anatomy of the heart Electrical anatomy of the heart Arteriosclerosis/atherosclerosis Constant increased pressure causes thickening of arterial wall Deposition of fatty plaque on inner surface of arterial wall Causative factors High salt diet High fat diet Smoking Diabetes Results Roughens inner surface of arterial wall Platelets attach to rough surface Thrombus formation Decreased elasticity Narrowed vessel lumen Angina Definition Ischemic heart pain Now referred to as NSTEMI Pathophysiology Workload of heart increases Coronary arteries are unable to provide adequate blood flow to myocardium for amount of work required Myocardium hurts when hypoxic Causes Arteriosclerosis Atherosclerosis May have "unstable angina" Continuous cardiac pain unresolved by rest, oxygen and nitroglycerin Signs and Symptoms Squeezing, dull pressure, chest pain commonly radiating down the arms or to the jaw resolving in less than 15 minutes Difficulty breathing Rapid, shallow breathing Dyspnea Skin Sudden onset of sweating (this in and of itself is a significant finding). Pallor Cyanosis 1

2 Subnormal temperature Signs and Symptoms Anxiety, irritability restlessness, or mental dullness Feeling of impending doom Pulse Irregular Weak Tachycardia Low or decreasing blood pressure Nausea/vomiting Myocardial Infarction Definition Ischemic heart damage Now referred to as STEMI Pathophysiology Coronary arteries are obstructed Hypoxic myocardial pain Tissue death Myocardial Infarction Causes Arteriosclerosis Atherosclerosis Thrombosis/Embolism (blood clot) Coronary artery spasm Intense muscular contraction of coronary arterial wall Halts distal blood flow May or may not be relieved Signs and Symptoms Squeezing, dull pressure, chest pain commonly radiating down the arms or to the jaw lasting more than 15 minutes Difficulty breathing Rapid, shallow breathing Dyspnea Skin Sudden onset of sweating (this in and of itself is a significant finding). Pallor Cyanosis Subnormal temperature Signs and Symptoms Anxiety, irritability restlessness, or mental dullness Feeling of impending doom Pulse Irregular Weak 2

3 Tachycardia Low or decreasing blood pressure Nausea/vomiting Congestive Heart Failure Definition Failure of the heart to effectively pump blood due to weakening of the muscle tissues Pathophysiology Starling's law Normally, the greater the heart muscle is stretched, the more forceful the resulting contraction Physiologic limit Myofibrils are "overstretched" and can no longer effectively contract Congestive Heart Failure Causes Hypertension Coronary artery disease Myocardial Infarction Heart valve disease Cardiomyopathy Heart muscle grows larger than blood supply Congenital heart disease Alcoholism Left-sided congestive failure (LCHF) Left ventricle cannot pump effectively enough to move blood into systemic circulation LCHF Pulmonary effects Less blood received from Left Atrium Increased atrial pressure Blood remains in pulmonary veins and capillary beds of the lungs Increased pulmonary capillary pressure causes plasma to cross alveolar membrane and enter alveoli Pulmonary edema Decreased oxygen exchange LCHF Systemic effects Less blood pumped to body by the left ventricle Decreased cardiac output Tissue hypoxia Signs & symptoms of LCHF Dyspnea 3

4 Exertional Resting Respiratory noises Rales Rhonchi Wheezing Frothy, pink sputum Cough Atypical chest pain Weakness and fatigue Restlessness Tachycardia Right-sided congestive failure (RCHF) Right ventricle cannot pump effectively enough to move blood into pulmonary circulation RCHF Systemic effects Less blood received from Right Atrium Increased atrial pressure Blood remains in Vena Cava's, systemic veins and capillary beds of the body Increased capillary pressure causes plasma to cross capillary membrane and enter interstitial space Interstitial edema Decreased oxygen exchange RCHF Pulmonary effects Less blood is pumped into pulmonary circulation Less oxygenation of available blood Tissue hypoxia Particularly on exertion Signs & symptoms of RCHF Venous distention Jugulars Other bodily veins Generalized edema Lower extremities Feet Lower legs "Pitting" Indent with finger A "pit" remains Ascites Fluid within peritoneum Plasma crosses capillary wall of intestinal tract Upper abdominal pain Liver becomes engorged and tender Nail Clubbing 4

5 Patients can have both right and left sided congestive heart failure Patient exhibits signs and symptoms of both Emergency Medical Care Airway May need to suction CHF patient Mechanical airway if unresponsive Breathing High flow oxygen» Non-rebreathing 15 LPM Bag-valve-mask assembled and ready Assist and supplement breathing or ventilate as necessary Circulation Check pulse; CPR may be indicated IV normal saline TKO (may use INT) 20cc/kg IV bolus followed by TKO rate if using AED or patient in PEA Place patient in position of comfort Promptly transport Aspirin (ASA) Therapy for all patients with new pain suggestive of MI Description Thrombolytic Actions Reduces overall mortality from acute myocardial infarction (AMI). Reduces additional infarct. Reduces strokes. Blocks formation of Thromboxane A2 which causes platelets to aggregate and arteries to constrict. Contraindications Patients with acute ulcer disease, GI or other bleeding disorders Patients experiencing an asthma attack If the patient has already had an ASA prior to arrival Known hypersensitivity to aspirin Precautions Patients with a history of Asthma, verify patient s known tolerance of aspirin Doses higher than recommended can interfere with Prostacyclin production and benefits (hormone that assists in clotting blood) Side Effects Sweating (usually at higher doses). Nausea (usually at higher doses). Fall in Blood Pressure (usually at higher doses). GI bleeding (usually at higher doses). 5

6 Dosage 160 mg to 325 mg Route Patients should chew one aspirin and take one by mouth If history of Angina, consider nitroglycerin (NTG) Medication name Generic - nitroglycerin Trade Nitrostat; Nitrobid; Nitrol Abbreviation - NTG Actions Relaxes blood vessels Decreases workload of heart Indications (must have all of the following criteria): Exhibits signs and symptoms of chest pain, Has physician prescribed NTG, and Has specific authorization by medical direction. Contraindications Hypotension or blood pressure below 100 mmhg systolic. Head injury Infants and children Patient has already met maximum prescribed dose prior to EMT-Basic arrival Medication form Tablet Sub-lingual spray Paste (old) Dosage One dose, repeat in 3-5 minutes if no relief, BP > 100, and authorized by medical direction up to a maximum of three doses Administration Obtain order from medical direction either on-line or off-line Perform focused assessment for cardiac patient Take blood pressure» Must be above 100 mmhg systolic Contact medical control if no standing orders Assure right medication, right patient, right route, patient alert Check expiration date of nitroglycerin Question patient on last dose administration, effects, and assures understanding of route of administration Ask patient to lift tongue and place tablet or spray dose under tongue (while wearing gloves) or have patient place tablet or spray under tongue Have patient keep mouth closed with tablet under tongue (without swallowing) until dissolved and absorbed Emergency Medical Care [Administration] (Cont.) 6

7 Record activity and time Perform reassessment Recheck blood pressure within 2 minutes Monitor blood pressure May require Trendelenburg positioning if precipitous drop Ask patient about effect on pain relief Seek medical direction before re-administering Record reassessments Side effects Hypotension Headache Sublingual burning Pulse rate changes Automated External Defibrillation (AED) Significantly increases survival of cardiac arrest victims when the patient is quickly defibrillated. Defibrillator s microprocessor evaluates the patient's rhythm and confirms the presence of a rhythm for which a shock is indicated. Normal chemo-electrical activity of the heart Depolarization Electro-chemical change resulting in contraction of the heart muscle Normally, fluid surrounding heart muscle fiber is high in sodium, low in potassium Normally, fluid inside cell is low in sodium, high in potassium Electrical stimulus from conduction system hits cell Cell permeability changes Sodium rushes in making interior of cell more positive than before Cell contracts Normal chemo-electrical activity of the heart Repolarization Electrochemical change resulting in restoration of heart muscle to state where it can once again contract Potassium is pumped out of the cell making the interior more negative After certain charge is reached, cell wall opens up and allows sodium to exit Potassium re-enters the cell and the cell is back to normal awaiting the next nervous stimulus Also known as the refractory period because cannot contract while repolarizing Rhythms Normal sinus rhythm Normal electrical signature of the heart P wave represents atrial depolarization QRS complex represents ventricular depolarization T wave represents ventricular repolarization 7

8 Ventricular fibrillation Wavy baseline Quivering of heart muscle Defibrillation indicated During ventricular fibrillation, cells are in mixed state of depolarization and repolarization Defibrillation causes all cells to depolarize and repolarize at the same time Afterwards, can resume normal electrical activity Asystole Flatline No movement of heart muscle Defibrillation useless Ventricular tachycardia Jagged, irregular baseline Poor ventricular refill, hence low or absent blood pressure Defibrillation indicated ONLY if patient unconscious Premature Ventricular Contractions (PVC s) Occasional premature beat Defibrillation NOT indicated PEA - Pulseless electrical activity (EMD - Electro-mechanical dissociation) Occasionally, the heart muscle fails to contract even in presence of normal electrical activity Heart monitor will show some type of rhythm, but the patient will have no pulse Always treat the patient, not the monitor Advantages of automated external defibrillation Speed of operation - first shock can be delivered within one minute of arrival at the patient's side Remote defibrillation through adhesive pads Defibrillation is "hands-off" Safer method Better electrode placement Has larger pad surface area Provokes less anxiety in EMT-Basic Rhythm monitoring - option on some defibrillator models Types of automated external defibrillators Fully automated - defibrillator operates without action by EMT-Basic, except to turn on power. Semi-automated - defibrillator uses a computer voice synthesizer to advise EMT-Basic 8

9 as to the steps to take based upon its analysis of the patient's cardiac rhythm. Interruption of CPR Chest compressions and artificial ventilations are stopped when the rhythm is being analyzed and when shocks are delivered Defibrillation is more effective than CPR, so stopping CPR during process is more beneficial to patient outcome CPR may be stopped up to 90 seconds if three shocks are necessary Resume CPR only after up to the first three shocks are delivered Safety considerations Attach defibrillator to only unresponsive, pulseless, nonbreathing patients to avoid delivering inappropriate shocks Defibrillator advises shocks for ventricular tachycardia when the rate exceeds a certain value, for example, above 180 beats per minute No person should be touching patient when rhythm is being analyzed and when shocks are delivered Water/rain Metal Defibrillator failure is most frequently related to improper device maintenance, commonly battery failure. Assure proper battery maintenance and battery replacement schedules Important to request ALS backup to continue the chain of survival The Chain of Survival EMS is only one part of a chain of people and systems that, when they work together, can increase the survival rate of pre-hospital cardiac arrest Trained or untrained bystanders that initiate the 911 system Trained bystanders who initiate CPR and/or defibrillation First responders EMT s Advanced life support In-hospital care Skill Cardiac Arrest Management/AED Skills Manual pages 61 & 62 Video Skill Chest Pain Therapy Skills Manual pages 66 & 67 Video 9

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