Cardiovascular Emergencies. January 2016 Continuing Education

Transcription

1 Cardiovascular Emergencies January 2016 Continuing Education

2 Cardiovascular Emergency Objectives Review the anatomy of heart structures, vessels and function. Review of the Cardiac Cycle Blood Flow through the Heart Electrical Conduction System of the Heart Case Study Formulate a field impression from a case study assessment and implement a treatment plan. Skill Drills (pt. assessment, cardiac monitoring, cardioversion) SMO Review

3 Epidemiology In 2007, heart disease contributed to about 34% of all US deaths. Heart disease is the number one killer. Kills 600,000 Americans each year About half in ED or before reaching a hospital During first minutes or hours Prevention strategies include education and early recognition.

4 Anatomy

5 Coronary Arteries Coronary arteries Left coronary artery supplies: Left ventricle Interventricular septum Part of right ventricle Coronary arteries (cont d) Right coronary artery supplies: Right atrium Right ventricle Part of the left ventricle

6 Valves Atria are separated from ventricles by atrioventricular (AV) valves: Tricuspid valve Mitral valve Semilunar valves Pulmonary semilunar valve Aortic semilunar valve

7 The Cardiac Cycle Represents complete depolarization and repolarization of the atria and ventricles Diastole: atria or ventricles are resting Systole: atria or ventricles contracting Relaxation phase: left atrium fills with blood under venous pressure Atrial contraction: blood in each atrium is squeezed into respective ventricle Atrial kick: contribution made by contraction

8 The Cardiac Cycle As ventricular contraction begins: Ventricles contract. Semilunar valves are forced open. Blood from the right ventricle is squeezed into the pulmonary arteries. Left ventricle blood is pushed into the aorta.

9 Blood Flow Through the Heart The heart acts as two pumps, separated by an interventricular septum. Right side: low-pressure pump Superior vena cava collects blood from upper body Inferior vena cava collects blood from lower body Left side: high-pressure pump Pulmonary veins collect blood from the lungs.

10 Blood Flow Through the Heart

11 Blood Flow Through the Heart Preload: initial stretching of cardiac myocytes prior to left-sided contraction Afterload: blood is driven out of the heart against systemic arteries Two circulations: Systemic circulation All blood vessels between left ventricle and right atrium Pulmonary circulation All blood vessels between right ventricle and left atrium

12 Blood Flow Through the Heart

13 The Electrical Conduction System of the Heart Cardiac cells have four properties: Excitability: allows response to electrical impulse Conductivity: ability to pass on electrical impulses Automaticity: can generate own electrical impulses Contractility: ability to contract Specialized conduction tissue propagates electrical impulses to the muscular tissue. Pacemaker: area where electrical activity arises Sets rate for cardiac contraction

14 The Electrical Conduction System of the Heart Sinoatrial node Located in right atrium Receives blood from the RCA Fastest pacemaker Impulses are spread through intermodal pathways, causing depolarization. Electrical impulses move from SA node to the atrioventricular (AV) node Impulse conduction is delayed so the atria will empty into the ventricles. Adapted from 12-Lead ECG: The Art of Interpretation, courtesy of Tomas B. Garcia, MD.

15 The Electrical Conduction System of the Heart Sinoatrial node (cont d): If atrial rate becomes rapid, not all impulses go through AV junction Normally pass: Into bundle of His Into right and left bundle branches Into Purkinje fibers

16 The Electrical Conduction System of the Heart Secondary pacemakers Any conduction system component can act as a secondary pacemaker if the SA node is damaged. The farther removed from the SA node, the slower the intrinsic rate of firing.

17 The Electrical Conduction System of the Heart Measuring the heart s electrical conduction activity Show as a series of waves and complexes on ECG Adapted from 12-Lead ECG: The Art of Interpretation, courtesy of Tomas B. Garcia, MD.

18 The Electrical Conduction System of the Heart

19 ECG Monitoring and Dysrhythmia Recognition Integral to interpreting the ECG rhythm is understanding the components of the normal ECG. You should become familiar with the following electrical events: P wave QRS complex T wave PR interval

20 ECG Monitoring and Dysrhythmia Recognition Each wave represents specific electrical events: P wave = Atrial depolarization QRS complex = Ventricular depolarization T wave = Ventricular repolarization P-R interval = Conduction from atria to ventricles Atrial repolarization is buried in the QRS complex

21 ECG Monitoring and Dysrhythmia Recognition The electrocardiogram (ECG).

22 ECG Monitoring and Dysrhythmia Recognition The relationship of the ECG (the heart s electrical activity) to the anatomical sequence of the heart s mechanical actions.

23 ECG Monitoring and Dysrhythmia Recognition MONITORING SYSTEMS Although varied, all heart monitors have the same basic components, including an oscilloscope or screen for viewing and a printer for a hard copy of the ECG. Remember how to interpret the ECG paper. Time is measured horizontally, and electrical amplitude is measured vertically.

24 ECG Monitoring and Dysrhythmia Recognition A breakdown of the ECG paper.

25 ECG Monitoring and Dysrhythmia Recognition ANALYZING THE ECG Interpreting ECG s is nothing more than assessing five parameters of the rhythm and applying a few rules. Rate Regularity QRS width P waves P-R Interval

26 ECG Monitoring and Dysrhythmia Recognition

27 Patient Assessment Cardiovascular common complaints: Chest pain Dyspnea Fainting Palpitations Fatigue Ensure scene safety. Anticipate the need for other resources. Look for clues to identify the potential problem

28 Primary Assessment Form a general impression. Observe general appearance. Assess for apparent life threats. Determine level of consciousness.

29 Primary Assessment Airway and breathing Determine airway patency. Check open airway for rate, quality, and effort of breathing. Consider oxygen therapy initiation.

30 Primary Assessment Circulation Check pulse: Conscious: radial pulse Unconscious: carotid pulse Note rate, regularity, and overall quality. Assess skin color and condition.

31 Primary Assessment Transport decisions Determine if immediate transport is needed. If unsure, continue assessment until answer can be determined.

32 History Taking Chest pain is often the presenting symptom of Acute Myocardial Infarction (AMI). Use OPQRST. Dyspnea is another chief complaint of ACS. A first indicator of left-sided heart failure When did it start? Suddenly or gradually? Continuous or intermittent? During activity or at rest? Does any position make it better or worse? Ever had it before? Cough? Associated symptoms?

33 History Taking Palpitations: sensation of abnormally fast or irregular heartbeat Often caused by dysrhythmia Inquire about: Onset, frequency, and duration Previous episodes Patients may also report: Feeling of impending doom Feeling nausea or having vomited Inquire about medical history.

34 Medications for Patients with Cardiovascular Diseases Patients may be taking a wide variety of medications. It is not always possible to identify the problem based on medications.

35 Case Study January 2016 CE Cardiovascular Emergencies

36 Part 1 You and your partner are enjoying the rare treat of a quiet Sunday shift. You are watching television, and your partner is studying for final exams. You are about to drift off when the pager disrupts the tranquility. You are dispatched to the medical school library for an unknown medical emergency. On arrival you and your partner are led to the third floor stacks where you find a 22- year-old man complaining of palpitations.

37 Part 1 (cont d) Primary Assessment Appearance Level of Consciousness Recording Time: 0 minutes Young, well-nourished man; appears anxious and nervous A (Alert to person, place, and day) Airway Open Breathing Circulation Normal rate, adequate volume Strong and rapid radial pulses with pink, warm, diaphoretic skin

38 Part 1 (cont d) What are some potential causes of palpitations? What questions would you like to ask your patient at this time?

39 Part 2 You ask your partner to obtain an initial set of vital signs while you begin your patient assessment. When asked about the palpitations, the patient tells you that they began about 45 minutes ago while he was studying for finals. He is a first-year medical student and needs to do well on finals to avoid being placed on academic probation. He admits to being awake for the past 36 hours with the help of Monster energy drinks and caffeine pills.

40 Part 2 (cont d) His last oral intake was pizza last night around 11:00 PM. He denies any medical history or allergies and emphatically denies the use of any drugs other than the caffeine pills.

41 Part 2 (cont d) Vital Signs Recording Time: 5 minutes Skin Pink, warm, and diaphoretic Pulse 210 beats/min, regular; strong radial pulses Blood Pressure 112/74 mm Hg Respirations 20 breaths/min, nonlabored SaO 2 95% on room air

42 What Rhythm is your patient in?

43 Remember.. SVT Rate > 150

44 Part 2 (cont d) What are some of your concerns based on this information? What interventions should you consider at this point?

45 Part 3 Your partner has applied the cardiac monitor and is giving oxygen at 4 L/min via nasal cannula. The cardiac monitor displays a narrow complex tachycardia at a rate of 212 beats/min. While looking for a site to insert an intravenous (IV) line, you ask the patient to bear down hard as if he were having a bowel movement. There is no change in his rate and rhythm. You insert an 18-gauge IV catheter in his right forearm and prepare to administer 6 mg of adenosine (Adenocard).

46 Part 3 (cont d) You rapidly administer the 6 mg of adenosine, followed by a 10- ml fluid bolus. The monitor showed a transient decrease in the HR to 165 beats/min, which quickly picked back up to a rate of 206 beats/min. Anthony tells you that he experienced the strangest sensation in his chest when you gave him the medication and asks what you gave him.

47 Part 3 (cont d) Reassessment Skin Pulse ECG Blood Pressure Respirations SaO2 Pupils Recording Time: 11 minutes Pink, warm, and diaphoretic 206 beats/min, regular; strong distal pulses Supraventricular tachycardia 110/78 mm Hg 20 breaths/min, nonlabored 99% on nasal cannula at 4 L/min of oxygen Equal and reactive to light

48 Part 3 (cont d) How does adenosine work? What should you tell your patient before you administer adenosine?

49 Part 4 Since the initial dose of adenosine caused a transient drop in the HR, you decide to administer 12 mg of adenosine after 2 minutes has passed. This time, you let Anthony know that you will be administering the medication and give it followed by a 10-mL flush. The monitor showed a 3-second period of asystole followed by a gradual increase in the HR to approximately 210 beats/min. After waiting 2 minutes, you administer another 12 mg of adenosine, the third and final dose, with similar results.

50 Part 4 (cont d) Reassessment Skin Pulse ECG Blood Pressure Respirations SaO 2 Pupils Recording Time: 17 minutes Pink, warm, and diaphoretic 210 beats/min, regular; strong distal pulses Supraventricular tachycardia 114/76 mm Hg 18 breaths/min, nonlabored 99% on nasal cannula at 4 L/min of oxygen Equal and reactive to light

51 Part 4 (cont d) How should your treatment proceed?

52 Part 5 (cont d) After about a minute passes, you note that the HR on the cardiac monitor begins to steadily decrease, finally stabilizing at 94 beats/min. Both you and Anthony can breathe a sigh of relief. You contact the receiving ED, give your report, and receive no further orders. On arrival at the ED, a diltiazem drip is started. He is admitted overnight for observation on the telemetry floor. After an uneventful night, Anthony is discharged home with strong suggestions not to overindulge in energy drinks and caffeine pills and to find healthier study habits!

53 Part 5 (cont d) Reassessment Skin Pulse Recording Time: 25 minutes Pink, warm, and dry 94 beats/min, regular; strong distal pulses ECG Blood Pressure Respirations SaO 2 Pupils Normal sinus rhythm 124/76 mm Hg 18 breaths/min, nonlabored 99% on nasal cannula at 4 L/min of oxygen Equal and reactive to light

54 Part 5 (cont d) Per ALS Code 7 of our SMOs what are the 5 signs of hypoperfusion? How should you treat this patient if he started to display signs of hypoperfusion? What is the first and second dose of this treatment?

55 Skill Drills 1. ALS Pt. Assessment with Cardiac Monitoring 2. Synchronized Cardioversion

56 SMO Review ALS Code 1 Initial Medical Care / Routine Cardiac Care ALS Code 7 Tachycardias

57 References Region 7 Standing Medical Orders, 2011 edition American Academy of Orthopedic Surgeons, Emergency Care in the Streets, 7 th Edition, Chapter 17, 2014 American Heart Association, Advanced Cardiac Life Support Textbook, May 2011.