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Chapter 14 Basic Cardiology For EMT’s Christopher Salo NREMT-P, LPN February 13, 2008
Objectives § Describe the structure and function of the cardiovascular system § Describe EMS care for chest pain patients, including oxygen, aspirin and nitroglycerin § Identify some causes of cardiac emergencies
Quick facts (not Farmer Fun Facts) § The heart beats on average 70 times per minute, 4200 times per hour, 100, 000 beats per day, 365 Million beats per year, and about 30 Billion beats in an average lifetime of 80 years. § The adult heart pumps 7, 500 liters of blood daily. § It takes 20 seconds to pump blood to every cell in your body.
§ Cardiovascular disease is the number one cause of death in the U. S. , and many times the first indication of this disease is an acute coronary event § Cardiac arrest is the most severe manifestation of an acute coronary syndrome, and with rapid intervention the EMT can make the difference between life and death
Basic Anatomy and Physiology § The cardiovascular system consists of: § Heart (The pump) § Major blood vessels (The hoses) § Arteries: Aorta, arteries, arterioles § Veins: Vena Cava, veins, venules § Capillaries: Nutrient, gas and waste product exchange § Blood (The fluid) § Cardiac Conduction System (The power)
The Heart § The heart is simply just a muscle. § It has four chambers: § Left and Right Atrium § Left and Right Ventricles § Valves: § Tricuspid and Bicuspid § Pulmonic and Aortic
Chambers of the heart § Atria: § Right atrium receives deoxygenated blood from the body § Left atrium receives oxygenated blood from the lungs § Ventricles § Right ventricle sends deoxygenated blood to the lungs § Left ventricle sends oxygenated blood to the body § The left and right sides of the heart are divided by the septum.
Major Vessels of the Heart § Vena Cava: Superior and inferior carry blood from body to the right atrium § Pulmonary Artery: Carries blood from right ventricle to the lungs for gas exchange § Pulmonary Vein: Carries freshly oxygenated blood back to the left atrium § Aorta: Carries blood from left ventricle out to the body
Valves § Valves prevent the backflow of blood through the § § system Tricuspid and Bicuspid valves on the right and left between the atria and ventricles Pulmonic valve between the right ventricle and pulmonary artery Aortic (Mitral) valve between the left ventricle and the aorta Veins also have valves to prevent backflow of blood. Arteries do not.
A picture is worth a thousand words
Cardiac conduction system § Each beat of the heart is actually just muscular § § contraction in reaction to an electrical impulse created by the heart itself. (Automaticity) The impulse starts at the Sinoatrial (SA) node located in the right atrium and travels through the atria, causing them to contract and squeeze the blood into the ventricles. (Atrial Kick) The impulse then is held at the Atrioventricular (AV) node, located between the atria and ventricles
Cardiac conduction continued § The impulse is held for a fraction of a second at the AV node to allow the ventricles to fill § The impulse then travels through the Bundle of His to the bundle branches and eventually to the Purkinjie fibers in the ventricles. § The ventricles respond to the impulse by contracting, causing ventricular systole, and forcing the blood out of the ventricles through the arteries
Blood flow through the system § Deoxygenated blood enters the right atrium from § § the inferior and superior vena cava Passes through the tricuspid valve to the right ventricle Is squeezed through the pulmonic valve and into the pulmonary artery to the lungs Gas exchange takes place, becomes oxygenated From the lungs into the pulmonary artery and into the left atrium
Blood flow continued § From the left atrium, through the bicuspid valve § § into the left ventricle Through the aortic valve and into the aorta The coronary artery, the first small vessel off the aorta, feeds blood to the heart itself Oxygenated blood travels through the aorta to all the arteries in the body (except the pulmonic artery) Arteries become smaller and smaller until they become arterioles, the smallest arteries
Blood flow continued § Arterioles connect to capillaries, which are one cell thick. § Cells take oxygen from the blood and rid themselves of waste products at the capillary level § Capillaries connect to venules, the smallest of the veins § Deoxygenated blood travels through larger and larger veins until they reach the vena cava and it starts all over again
Any Questions So Far? Good, now the hard part is over
Angina Pectoris § Angina Pectoris: Chest pain, usually brought on by § § § exertion. Indicates area of the heart is not perfusing adequately, causing ischemia. Usually lasts 2 -15 minutes and may be relieved with rest. Can radiate to neck, arms, jaw, back or shoulders. May have cool, clammy skin, diaphoresis, dyspnea, anxiety, N/V Women, elderly and diabetics may show atypical signs.
Ventricular Fibrillation § Ventricular Fibrillation. Ventricles simply quivering. § Ventricles not squeezing, no pulse, no blood flow § Total disorganized electrical activity in the heart § Early defibrillation is the key!!!
Ventricular Tachycardia § Ventricular Tachycardia§ § Ventricles beating so fast as to not pump blood adequately Limited diastolic period, not allowing ventricles to fill enough to provide adequate cardiac output Can progress to VF if not treated early May or may not have a pulse, pulse may be rapid, weak and thready Defibrillation if pulseless
Asystole § Asystole- Total absence of electrical activity in the heart. § Very low chance of recovery § AED will not allow defibrillation § Perform CPR until advanced care arrives
Pulseless Electrical Activity § PEA- The heart’s electrical system is firing in an organized rhythm, but the myocardium is not responding § No response by the muscle means no pulse, therefore, no circulation § Any rhythm seen on monitor that has no pulse is PEA § No defibrillation in cases of PEA
Signs and Symptoms of cardiac compromise § Squeezing, dull pressure, feeling of heaviness on chest, § § § § or sharp, stabbing pain in chest radiating to arm or jaw Sudden onset of perfuse sweating Pale skin Dyspnea Anxiety, irritability Feeling of impending doom Abnormal pulse or BP Epigastric pain Nausea or vomiting
Case Study § You are an EMT-B working for a basic service. You and your partner are enjoying a relaxing afternoon on a warm fall day. The radio screams to life “Unit XYZ, you are needed to respond to 321 Contact Drive for a 58 year old male with chest pain and shortness of breath”. You scramble to the rig and tear down the road with lights and sirens blaring. As you arrive at the address, a woman rushes out to meet your ambulance, “Please, please, you have to help him. Come on, hurry, I think he is having another heart attack”.
Now What? § Scene safe, BSI…. . Don’t Forget!!! § Scene size up: Number of patients, need for additional resources, get ALS rolling if they haven’t been already § General impression of patient: § 58 y. o. male, average build, sitting, clutching his chest, breathing labored and slightly fast § ABC’s § Seems alert, answers your questions § Skin pale and diaphoretic § History of present illness § SAMPLE history with OPQRST
SAMPLE § Signs and Symptoms: Chest pain, trouble breathing. Pt § § § clutching chest and labored breathing Allergies: Codine and amoxicillin Medications: ASA, NTG, Lasix, Toprol, Glucophage Past medical history: DM, HTN, AMI x 3, cardiac stenting Last oral intake: Ate lunch about 3 hours ago Events: Was cutting firewood for about an hour and developed the pain, came into the house to rest.
OPQRST § Onset- While cutting firewood § Provokes/ Palliative- Rest improves pain, § § exertion worsens it Quality- Sharp, stabbing pain in middle of chest on left side, feels like my last heart attack Radiation- Radiates to left shoulder and jaw Severity- 9/10 Time- 15 minutes ago, hasn’t stopped
What do we do? § While you were asking questions, your partner was getting vitals for you: § BP 164/96, P 104, R 22 and labored § You place him on oxygen, NRB @ 12 -15 LPM § ASSIST him with his Nitroglycerin, but be sure you follow the 5 rights § § § Right Patient Right Route Right Med Right Dosage Right time § If protocols permit, give aspirin, 325 mg total. Have patient chew and swallow. § LOAD AND GO!!!
Ongoing Assessment § Monitor vital signs, to include a pain scale every 5 § § § § minutes. Transport to your intercept or the hospital. How many times can you assist him with his NTG? And how often? What do you need before he takes any nitro? What if he doesn’t tolerate the NRB? In what position would you transport him? Would you transport code 1 or code 3? What if he passes out? What if he stops breathing? What if his heart stops?
Oxygen Therapy § Who gets oxygen? § How are we going to give it? § How much are we going to give? § Who doesn’t get oxygen? § Remember, technically oxygen is a drug, always chart the response to administration.
Nitroglycerin § As EMT-Basics we can ASSIST patients take their § § § Nitroglycerin tablets or sprays. Dosage is 0. 3 -0. 4 mg per tab or spray Make sure you follow the 5 rights. Make sure the medication isn’t expired. Place tablet under the tongue, remind patient not to chew or swallow it, just let it dissolve. Must have systolic BP over 90 prior to administration. Can be given every 3 -5 minutes, up to 3 times provided systolic BP is over 90 and patient is not pain free.
NTG continued § Nitroglycerin is a vasodilator, it works by opening up the vessels to the heart, allowing more oxygen to get to the ischemic areas that are causing the pain. § Pt will most likely develop a headache, possibly some dizziness. § Contraindicated if BP below 90 systolic, HR below 50 or above 100, suspected head injury, or if pt has taken “daddy’s little helpers”
Aspirin § Aspirin has a rapid acting antiplatelet effect, which helps prevent clot formation. § Usual dosage for CP is 160 -325 mg. § Chewable “baby” aspirin 81 mg each. § Give 81 mg X 4, chew and swallow. § Contraindications: Already taken ASA or hypersensitivity to ASA.