Cardiovascular Emergencies Robert S. Kiken DDS Ocean Oral and Maxillofacial Surgery Santa Barbara, CA 1 Management of Office Anesthetic and Medical Emergencies – a Systems Approach Cardiovascular emergencies involving the conducting system Cardiovascular emergencies involving the vascular system Endocrine/Diabetic emergencies 2 Deliver Oxygen & Prevent Hypoxia Deficiency in the amount of oxygen reaching the tissues. Can cause dysrhythmias, cardiac arrest, brain damage, and death. We must have: Adequate Circulation pump and conducting system An unimpaired Airway Uncompromised Breathing 3 1 The Foundation 4 Cardiovascular emergencies involving the conducting system - EKG Interpretation 5 Conduction System: Basic Anatomy SA Node: Bundle of primary His pacemaker Internodal Bundle pathways branches and atria Purkinje AV fibers Node 6 2 SA Node Basic Electrophysiology Depolarization of the Ventricles AV Node Repolarization of the Ventricles Relationship of EKG to Anatomy of Cardiac Conduction system P QRS T 7 The Electrocardiogram Repolarization of Depolarization of the Ventricles the Ventricles Depolarization of the Atria Hypokalemia or other metabolic disturbance What does the EKG tell us? 8 Rules Of EKG Interpretation Look For: Rate Rhythm Regularity 9 3 Rate How fast is the heart beating? 80 beats per Start where an R wave minute falls on a heavy line 10 Another approach to find the rate is to divide 300 by the number of large boxes between R waves. 1 2 3 4 5 6 In this case we’ll divide 300 by 6: 300 ÷ 6 = 50 1 2 In this case we’ll divide 300 by 2: 300 ÷ 2 = 150 11 Automaticity Foci (Ectopic Foci) Foci throughout the heart have the property of “automaticity” i.e. they can initiate an action potential and become the heart’s pacemaker Automaticity foci may be located either: In the atria In the AV Junction In the ventricles 12 4 Automaticity Foci Foci in each of these areas has an inherent discharge rate SA Node 60-100/min INHERENT LEVEL RATE RANGE Atria 60 - 80/min. AV Junction 40 - 60/min. Ventricles 20 - 40/min. 13 As You Count The Boxes, Consider If The Rate Is A Problem. 2 Boxes When there are less than two boxes between R waves or 8 Boxes When there are more than five boxes between R waves (in this example 8 boxes) 14 Rhythm Do all the beats look the same? Is it like wallpaper? And, can you dance to it? 15 5 Rhythm If the beats all look the same… …do they look worrisome? 16 Rhythm Disturbances Arrhythmias may be either: Supraventricular Arrhythmias - above the level of ventricles Combined Arrhythmias -above and within the ventricles Ventricular Arrhythmias - within the ventricles 17 Regularity Are the beats evenly spaced? A ==B C = D { { { { 1 18 6 Principles of EKG : Helpful Hints 19 1. Identify the QRS Complexes Start 150 75 300 100 Can you identify them?...and • What is their rate? 20 2. Is the QRS complex width normal? ½ Normal is < 0.11 sec (no more than ½ large block) 21 7 3. Is there a P wave in front of each QRS? 22 4. Is the P-R interval normal? 3-5 small blocks Normal is 0.12 - 0.20 sec (3-5 small blocks) 23 EKG Interpretation of Cardiac Dysrhythmias Bradycardia Sinus tachycardia Stable tachycardias Unstable tachycardias Arrest rhythms: Ventricular fibrillation & pulseless ventricular tachycardia Asystole & PEA 24 8 Normal Sinus Rhythm and Sinus Dysrhythmias Normal Sinus Rhythm (NSR) Sinus Arrhythmia (Sinus Dysrhythmia) Sinus Bradycardia Sinus Tachycardia 25 Vagus Normal Sinus Rhythm (NSR) SA Defining characteristics: • All components present i.e. P, QRS and T waves • Regular rate and rhythm of AV 60 -100 bpm • PR = 0.12 – 0.20, QRS = < 0.12 Start 150 75 P QRS T 300 100 PR =.12 - .20 QRS < .11 83 26 Normal Sinus Rhythm (NSR) Rate Defining characteristics: • All components present i.e. P, QRS and T waves • Regular rate and rhythm of 60 -100 bpm • PR = 0.12 – 0.20, QRS = < 0.12 27 9 Sinus Arrhythmia Defining characteristics: • Similar to NSR except for irregular rate • Rate varies somewhat with inspiration and expiration • Decrease in PNS on inhalation results in an increase in heart rate • Usually a normal finding Start Start 48 150 75 60 150 75 50 300 100 60 300 100 60 28 Sinus Arrhythmia Rate Defining characteristics: • Similar to NSR except for irregular rate • Rate varies somewhat with inspiration and expiration • Usually a normal finding 29 Premature Atrial Contraction (PAC) Rate Defining characteristics: • Overall NSR except for isolated early P waves • Beat with early P wave usually followed by a beat containing a compensatory pause 30 10 Bradycardia 31 Sinus Bradycardia Defining characteristics: • Like NSR, but with rate < 60 • May be due to increased parasympathetic tone • Seen as a normal finding in athletes Start 150 75 50 50 300 100 60 32 Sinus Bradycardia RATE Defining characteristics: • Like NSR, but with rate < 60 • May be due to increased parasympathetic tone • Seen as a normal finding in athletes 33 11 78 year old medically compromised patient with bradycardia Pre-Op QRS Wider No P Intra-Op PVC 34 Persistent Bradycardia • Causing: • Hypotension • Altered mental status • Signs of shock • Ischemic chest discomfort • Acute heart failure • Treat… 35 Treat Persistent Bradycardia Causing: Symptoms Signs • Chest discomfort • Hypotension • Shortness of breath • CHF • Decreased level of • Ventricular consciousness arrhythmia related • Weakness to the bradycardia • Fatigue • Dizziness • Syncope 36 12 Bradycardia - Treatment Atropine effect takes “foot off of Vagus Nerve the brake” X Dopamine effect – puts “foot on the gas” 37 Diagnosis: Pulse < 60 is “bradycardia,” but treat patient, not monitor Position: Semi-seated, comfortable Initial Management: Observe, ABC’s, 02, IV, Monitor If Stable: • Continue to observe, ABC’s, 02, IV, Monitor If Unstable, Treat With: • Atropine • If atropine ineffective: • Transcutenous pacing • Dopamine • Epinephrine 38 Bradycardia - Atropine • Atropine 0.5 mg IV every 3-5 minutes to total dose of 3 mg. • A dose less than 0.5 mg may further decrease heart rate. • May worsen ischemia or increase infarction size. • Ineffective in cardiac transplant patient. • If type II/2 or 3rd degree block, atropine will likely be ineffective. 39 13 Bradycardia - Dopamine • Dopamine 2-10 mcg/kg/minute. • Has both α- and β-adrenergic actions. • Titrate to target heart rate or vasoconstriction. • Lower dose: inotropy and heart rate. • Higher dose: (>10) vasoconstriction. • Good choice if bradycardia and hypotension. • Adequate intravascular volume. 40 Bradycardia - Epinephrine • Epinephrine 2-10 mcg per minute. • α- and β-adrenergic actions. • Good choice if bradycardia and hypotension. 41 Tachycardia 42 14 Cardiac Dysrhythmias -Tachycardias • Sinus Tachycardia • Atrial Tachycardias - usually “Narrow Complex” • Ventricular Tachycardias - usually “Wide Complex” 43 SA Sinus Tachycardia Defining characteristics: • Similar to NSR except for increased rate of > 100 bpm AV • Frequently seen during adrenergic stimulation 115 Start 150 300 100 44 Sinus Tachycardia Rate Defining characteristics: • Similar to NSR except for increased rate of > 100 bpm • Frequently seen during adrenergic stimulation 45 15 Atrial Dysrhythmias – Usually “Narrow Complex” • Premature Atrial Contraction (PAC) • Paroxysmal Supraventricular Tachycardia (PVST) • Atrial Fibrillation (A. Fib.) • Atrial Flutter (A. Flutter) • Multifocal Atrial Tachycardia (MAT) 46 Ectopic focus Premature Atrial within the Contraction (PAC) atrium Defining characteristics: • Overall NSR except for isolated early P waves • Beat with early P wave usually followed by a beat containing a compensatory pause 2X Y + Z = 2X X X Y Z Compensatory Pause 47 An atrial pacemaker takes over Paroxysmal Supraventricular Tachycardia (PSVT) Defining characteristics: • Regular, narrow complex tachycardia (150- 250 bpm) • Sudden (paroxysmal) onset • Merged P-T waves Merged P-T waves Rate increased from 83 to187 Normal sinus beats 48 16 Paroxysmal Supraventricular Tachycardia (PSVT) Rate Defining characteristics: • Regular, narrow complex tachycardia (150-250 bpm) • Sudden (paroxysmal) onset • Merged P-T waves 49 Atrial Fibrillation (A. Fib.) Defining characteristics: • Multiple ectopic foci within the atria create a wavy baseline consisting of small erratic spikes • An ectopic focus near the AV node may conduct into the ventricles and generate a QRS. • Irregular ventricular rate Ventricular rate highly variable R R R Wavy baseline with small erratic spikes 50 Atrial Fibrillation (A. Fib.) Rate Defining characteristics: • Multiple ectopic foci within the atria create a wavy baseline consisting of small erratic spikes • An ectopic focus near the AV node may conduct into the ventricles and generate a QRS. • Irregular ventricular rate 51 17 An ectopic circular conduction loop Atrial Flutter (A. Flutter) Defining characteristics: • A chaotic circular conduction path creates a “saw tooth” baseline of “flutter waves.” • Slower ventricular rate, usually in a 3:1 or 4:1 ratio to flutter waves A “saw tooth” pattern of F waves F F F F 52 Atrial Flutter (A. Flutter) Rate Defining characteristics: • A chaotic circular conduction path creates a “saw tooth” baseline of “flutter waves.” • Slower ventricular rate, usually in a 3:1 or 4:1 ratio to flutter waves 53 Multifocal Atrial Tachycardia • Irregularly irregular • Distinguished from atrial fibrillation by the presence of P waves. • Pulmonary disease or multi-system issue (sepsis, shock, electrolyte abnormalities) 54 18 Ventricular Dysrhythmias – Usually “Wide Complex” (i.e. the QRS Complex is Wide ) • Premature