[医药卫生]心电图诊断教程.ppt

HLT0073 Cardiac Diagnostics Instrumentation,Class 9 Instructor: Joanne Lambley, MSc (Kin),Agenda,Emergency Management Components of Emergency Management Plan Equipment on the Crash Cart Medications on the Crash Cart Defibrillators AEDs Manual Medications in the Testing Room,Emergency Management Plan,From ACSM, 2006 All personnel should be trained in CPR Preferably ACLS Should be at least 1 ACLS trained staff and a physician immediately available Communication: Phone numbers for emergency assistance should be posted on all phones Emergency communication devices must be available and working properly ie. Physician call button, Code Blue button,Emergency plans should be: Posted Rehearsed quarterly Specific person should be assigned to regular maintenance of emergency equipment and inventory of drugs RT department maintains crash carts Cardiology technologists inventory emergency drugs in testing rooms Stock (all necessary meds are present) Expiry dates,Equipment and drugs should be in all areas where maximal ETT is performed Only personnel authorized by law to use certain equipment can do so (equipment must be immediately available),Equipment on the Crash Cart,Portable, battery-operated defibrillator monitor Hardcopy printout or memory Cardioversion capability AC power source in case of battery failure Capable of monitoring Blood pressure equipment Airway supplies Oxygen,,Equipment on the Crash Cart,AMBU bag Suction equipment IV fluids and stand IV access equipment Syringes and needles (multiple sizes) Adhesive tape, alcohol wipes, gauze pads Emergency documentation forms,www.sands.ca,Medications on the Crash Cart (not responsible for meds on test 3),Drugs are in IV form VF/pulseless VT Epinephrine Vasopressin Antiarrhythmics Amiodarone Lidocaine Magnesium Procainamide,Medications on the Crash Cart,PEA (pulseless electrical activity), asystole Epinephrine Atropine Acute coronary syndromes: ischemia and chest pain, including: Oxygen Aspirin (oral) Nitroglycerine (oral or IV) Morphine (if pain not relieved with NTG) -adrenergic blockers Heparin,Medications on the Crash Cart,Bradycardias, for example: Atropine Stable and unstable tachycardias, for example: Adenosine -adrenergic blockers Calcium channel blockers Digoxin Procainamide Amiodarone Lidocaine,Defibrillation,Delivery of large amounts of electric current through the chest over a very brief period of time Depolarizes myocardial cells to allow coordinated activity to resume (terminating VF) Electrophysiological event that occurs 300 to 500 milliseconds after shock delivery VF frequently reoccurs after a successful shock,2 Types of Defibrillators,Automated External Defibrillators (AEDs): To be used by lay rescuers or healthcare providers Part of basic life support Manual defibrillators (with cardioversion, pacing capabilities) Advanced life support therapies,Automated External Defibrillators,Increased presence in nonmedical settings Airports Airplanes Shopping centers Casinos,AED,Computerized devices Use voice and visual prompts Guide lay rescuers and healthcare providers to safely defibrillate VF New prototypes may provide information about frequency and depth of chest compressions,AED,Assess heart rhythm through electrodes on torso If needed, the AED advises responder to administer a shock to restore normal rhythm Small, lightweight,/aeds/,AED,,www3.kmu.ac.jp,AED,AED,Microprocessors analyze frequency and amplitude of the ECG signal Filters check for: QRS-like signals Radio transmission 50 or 60 Hz interference Loose electrodes Poor electrode contact Some programmed to detect spontaneous movement by patient or others Proven to be very accurate in rhythm analysis,New BLS and ACLS Guidelines,2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care /content/vol112/24_suppl Webcast: /presenter.jhtml?identifier=3037720#hospital,Defibrillation and CPR,Early defibrillation critical to survival from sudden cardiac arrest Why? Most frequent initial rhythm is VF Treatment for VF is defibrillation Probability of successful defibrillation decreases rapidly as time passes VF tends to deteriorate to asystole within a few minutes CPR prolongs VF and provides some oxygen and substrates to the heart and brain Unlikely to eliminate VF without defibrillation,Defibrillation and CPR,For the best chance of survival, 3 actions must occur with the first few moments: Activation of EMS Provision of CPR Operation of an AED How do we integrate CPR and defibrillation?,Shock First versus CPR First,For an out-of-hospital witnessed arrest, with an AED available: Use the AED as soon as possible For an out-of-hospital unwitnessed arrest: Provide 2 minutes of CPR, then defibrillate,One Shock vs Three Shocks,Interruption in chest compressions is associated with a decreased probability of cardioversion from VF AEDs provide 3 “stacked” shocks Results in a delay of 37 seconds between delivery of the first shock and delivery of the first post-shock chest compression Usually the first shock is 90% effective If the first shock is ineffective, the chance that shocks 2 and 3 will defibrillate patient is low Better to resume CPR after 1 shock,Protocol,For VF/pulseless VT: Deliver 1 shock Immediately reassume CPR beginning with chest compressions Do not delay to recheck rhythm or pulse After 2 minutes of CPR, AED should analyze rhythm and deliver another shock if indicated If unshockable rhythm detected, resume CPR,Monophasic versus Biphasic,Monophasic waveforms: Deliver current of one polarity (one direction of current flow) In older models of defibrillators Biphasic waveforms: Passes sequential waves of current through the heart in opposite directions Allow lower levels of energy to be delivered with the same or better result,Electrode Placement,Place on victims bare chest Right (sternal) chest pad placed on right superior-anterior (infraclavicular) chest Left (apical) chest pad placed on left interior-lateral chest (lateral to the left breast),Electrode Placement,If an implantable medical device is located where a pad should be placed, position the pad at least 1 inch from the device Do not place pads directly on top of a transdermal medication patch Nitroglycerin Nicotine Hormone replacement Analgesics Why? The patch may: Block delivery of energy from the electrode pad to the heart Cause burns to the skin Remove medication patches and wipe the skin before attaching pads,Electrode Placement,Remove victim from water and wipe the chest before attaching electrodes Wipe chest is patient is extremely diaphoretic AEDs can be used if the patient is lying in snow or ice If the electrodes will not adhere due to chest hair, pull off electrode pad to remove the hair and place a new one on the chest,Inhospital Use of AEDs,Defibrillation may be delayed: Unmonitored hospital beds Outpatient clinics Diagnostic facilities Several minutes may elapse before Code Blue teams arrive with a defibrillator, attach it, and deliver shocks AEDs may provide early defibrillation (goal of 3 minutes from collapse),Manual Defibrillation,Use electrode paste with paddles or gel pads Ensure paddles are in full contact with skin Avoid touching paddles to ECG leads Do not allow gel to smear across chest Do not place paddles over ICD or pacemaker May block flow of current to the heart,Fire Hazard,Fire can be ignited by sparks from poorly applied defibrillator paddles in the presence of an oxygen-rich atmosphere Ventilator tube disconnected from tracheal tube and left adjacent to victims head Blows oxygen across chest during defibrillation Use of self-adhesive defibrillation pads best way of minimizing sparks,Synchronized Cardioversion,Shock delivery that is timed (synchronized) with the QRS complex “sync” mode Searches for the peak of the QRS complex Avoids shock delivery during the “vulnerable period” of cardiac repolarization (which is more likely to induce VF),Synchronized Cardioversion,Indicated to treat unstable tachyarrhythmias with an organized QRS complex and a perfusing rhythm (pulse) Unstable patient has signs of poor perfusion: Altered mental status Ongoing chest pain Hypotension Unstable supraventricular tachycardia: Reentry, atrial fibrillation, atrial flutter Unstable monomorphic VT,Pacing,Not recommended for patients in asystole Better to maximize chest compressions Pacing is recommended for treatment of symptomatic bradycardia,Maintaining Devices,User checklists have been developed to reduce equipment malfunction and operator errors Majority of malfunctions due to: Failure to maintain defibrillator Failure to maintain power supply,Meds in the Testing Room,Nitroglycerin spray (may be given by Tech) Relaxes vascular smooth muscle, dilates large coronary arteries and increases coronary collateral circulation Sublingual delivers 0.4 mg per spray Relief usually occurs in 1 to 2 minutes Monitor blood pressure before and after dose Repeat at 5 min intervals Call MD if first dose does not improve chest pain or if BP falls (patient should be sitting or lying down),Meds in the Testing Room,Ventolin and Atrovent (may be given by Tech) Patients with a history of asthma may be at greater risk of bronchospasm from persantine Given prior to persantine