Department of Emergency and Disaster Medicine Medical University of LODZ

Transcription

1 Electrotherapy in emergency states Department of Emergency and Disaster Medicine Medical University of LODZ

2 defibrillation

3 defibrillation The purpous of defibrillation is to deliver a randomly timed high-energy electrical current to the heart that is fibrillating to restore a normal sinus rhythm

4 DEFIBRILLATION - indications Defibrillation is indicated when ventricular fibrillation or ventricular tachycardia has not spontaneously converted to an organized rhythm. Ventricular fibrillation and ventricular tachycardia are rarely spontaneously reversible and are not compatible with life.

5 ALS algorithm Cardiac arrest BLS attach monitor/defibrillator Check rhythm VF/FT Non FV/FT Give 1 shock Reasume CPR immediatly (5 cycles) CPR for 5 cycles Epinephrine 1mg iv Consider atropine 1mg iv AS

6 DEFIBRILLATION - contraindications There are few contraindications to defibrillation. The main contraindication is in a patient who has made it clear that he or she does not wish to be resuscitated. Defibrillation should not be used for arrhythmias other than ventricular tachycardia or ventricular fibrillation.

7 EQUIPMENT Defibrillator I cardioversion unit Conductive jell elly or pads Suction source, tubing, and catheter Airway management supplies Advanced Cardiac Life Support (ACLS) medications Intravenous sedative agents Cardiac monitor Noninvasive blood pressure monitor Pulse oximeter Oxygen source and tubing Nasal cannula or face mask to deliver oxygen

8 EQUIPMENT The typical detibrillator/cardioversion unit performs cardioversion, detibrillation, transcutaneous cardiac pacing and ecg The unit is self-contained. It plugs into a standard electrical outlet. The unit also contains rechargeable batteries, An oscillosco provides real-time monitoring of the patient's cardiac rhythm. A continuous electrocardiographic (ECG) rhythm strip providing documentation on paper is standard with each unit, producing a hard copy to attach to the patient's medical record. Numerous dials or electronic touchpads with digital displays allow thenumerous dials or e operator to set the working mode ode, energy level, pacemaker settings, and oscilloscope input (ECG leads or "quick-look paddles). The depolarizer within the machine provide direct electric current forthe depolarizer wit cardioversion and defibrillation.

9 The paddles The paddles must be firmly applied to the patient's torso. (They allow a "quick look" and transmit the patient's cardiac rhythm to the oscilloscope) Each paddle bas a button on which a thumb is to be placed. This serves as a safety mechanism. Both buttons must be depressed simultaneously to discharge the current. (This prevents accidental and premature discharge of current, which may injure the patient, the operator, or bystanders.) Some units use self-adhesive disposable patches as an alternative to paddles. Electrically conductive contact medium should always be applied between the electrode and the patient's chest wall. - a gel or paste. (Conductive pads are commercially available but significantly more expensive than gel or paste)

10 Adult padiles The paddles - shapes and tapes are round, oval, or rectangular in shape. They meąsure 8 to 10 cm in greatest diameter. (They can be used on children weighing more than 10 kg or over l year of age, adolescents, and adults.) Pediatric paddles are round, oval, or rectangular in shape. They meąsure 4 to 6 cm in greatest diameter. Larger paddles will allow a greater amount of myocardium to be depolarized while decreasing the current density applied, so as to minimize myocardial injury. The paddles must be at least 2 to 3 cm apart to prevent electrical bridging and burn injury to the child. Using paddles that are too large will deliver the electric current over too great an area and decrease its effectiveness.

11 The paddles - position Anterolateral pad and paddle positioning Anteroposterior pad and paddle positioning

12 TECHNIQUE Stand at the patient's left side. Thurn on the defibrillator unit. Set the display to the "quick- look" paddles. Remove any fluid materiais on the chest wall (conductive jelly, saline, sweat, urine, water), as they can form a bridge between the paddies and result in arcing and thermal bums to the thorax. AIso remove any nitroglycerinarcing patches and thermal bum or ointments from the patient's torso. Ensure that there are no open oxygen sources that could ignite when Ensure the unit that is there are n discharged. Grasp the left paddle (sternum) with the left hand and the right paddle (apex) with the right hand. This is the anterolateral paddle position. Apply the paddles and observe the patient's cardiac rhythm. Set the energy level Charge the paddles Ensure that nurses and other assistans are not touching the patientsensure or the that nurses and stretcher deliver the charge by simultaneously pressing the discharge buttonsdeliver each the charge by si paddle. Observe the monitor and reevaluate the patient's cardiac rhythm and start ALS

13 defibrillation - energy Cardiac rhythm Initial monophasic energy Initial biphasic energy Ventricular fibrillation /pulsless ventricular tachycardia 360J J (device specific)

14 Complications Thermal and electrical burns - Skin burn rns may result, the severity of which increases depending on the energy level utilized and the number of shocks delivered. Care must be taken to avoid contact between the ECG monitor leads and the paddies, or of the paddies with each other, as sparks or fire may result. Burn rns can be minimized by utilizing electrically conductive contact media and firmly applying the paddles to the patient.

15 cardioversion

16 cardioversion Synchronized cardioversion is shock delivery that is timed (synchronized) with the QRS complex. This synchronization avoids shock delivery during the relative refractory portion of the cardiac cycle, when a shock could produce VF. The energy (shock dose) used for a synchronized shock is lower than that used for unsynchronized shocks (defibrillation). These low-energy shocks should always be delivered as synchronized shocks because if they are delivered as unsynchronized shocks they are likely to induce VF.

17 Cardioversion - indications Delivery of synchronized shocks (cardioversion) is indicated to treat unstable tachyarrhythmias associated with an organized QRS complex and a perfusing rhythm (pulses). The unstable patient demonstrates signs of poor perfusion, including altered mental status, ongoing chest pain, hypotension, or other signs of shock (eg, pulmonary edema). Synchronized cardioversion is recommended to treat unstable supraventricular tachycardia due to reentry, atrial fibrillation, and atrial flutter. These arrhythmias are all caused by reentry, an abnormal rhythm circuit These arrhythmia that allows a wave of depolarization to travel in a circle. The delivery of a shock can stop these rhythms because it interrupts the circulating (reentry) pattern. unstable monomorphic VT.

18 TECHNIQUE Stand at the patient's left side. Thurn on the cardioversion unit. Set the display to the "quick- look" paddles. Remove any fluid materiais on the chest wall (conductive jelly, saline, sweat, urine, water), as they can form a bridge between the paddies and result in arcing and thermal bums to the thorax. AIso remove any nitroglycerinarcing patches and thermal bum or ointments from the patient's torso. Ensure that there are no open oxygen sources that could ignite when Ensure the unit that is there are n discharged. Grasp the left paddle (sternum) with the left hand and the right paddle (apex) with the right hand. This is the anterolateral paddle position. Apply the paddles and observe the patient's cardiac rhythm. Set the energy level Charge the paddles Ensure that nurses and other assistans are not touching the patientsensure or the that nurses and stretcher deliver the charge by simultaneously pressing the discharge buttonsdeliver each the charge by si paddle. Observe the monitor and reevaluate the patient's cardiac rhythm

19 The paddles - position Anterolateral pad and paddle positioning Anteroposterior pad and paddle positioning

20 Cardioversion - energy Cardiac rhythm Initial monophasic energy Initial biphasic energy Atrial fibrillation J No dates Atrial flutter and other supraventricular tachycardias J No dates Ventricular tachycardias 100J No dates

21 complication Thermal and electrical burns Occasionally hypertension, other arrhythmias, ventricular fibrillation or heart block may develop. Systemic emboli may occur from ciots in the Ieft atrium becoming disiodged if the underiying rhythm prior to the cardioversion or defibriiiation is atrial fibrillation. Do not appiy the paddles directly over an impianted defibrillator or pacemaker. The eiectric discharge can permanently damage these devices. Avoid injury to yourself or others by ensuring that no one is in contactavoid injury to with the bed or the patient when the shock is administered. Such injuries can lange from mild shocks and burn rns to cardiac dysrhythmias.

22 Transcutaneous cardiac pacing

23 Transcutaneous cardiac pacing Pacing can be considered in patients with severe, symptomatic, or hemodynamically unstable bradyarrhythmias that do not respond to pharmacologic therapy Pacing is not recommended for patients in asystolic cardiac arrest. Transcutaneous pacing is recommended for treatment of symptomatic Transcutaneous bradycardia pacing is when a pulse is present. Healthcare providers should be prepared towhen initiate a pulse is prese pacing in patients who do not respond to atropine (or second-line drugs if these do not delay definitive management). Immediate pacing is indicated do if the not delay definitiv patient is severely symptomatic, especially when the block is at or below patient theis severely sym His Purkinje level. If the patient does not respond to transcutaneoushis pacing, Purkinje level. If th transvenous pacing is needed.

24 TECHNIQUE Explain the purpose of TCP to the patient or their representantive Prepare the skin for placement of the electrode patches. Clean any dirt and debris from the skin. lf necessary, use soap and water Clean any dirt and d to clean the skin. Avoid flammable cleaning liquids, such as alcohol- containing solutions. in patients with excessive body hair, shaving may be I required to ensure in patients with exc good skin-electrode contact. The pacing electrodes must be applied to the thorax Connect the electrodes to the pacing generator. Set the pacing rate to 80 beats per l minute. In the setting of a unconscious patients, it is recommended to turn the stimulating current to maximal output (200 ma) to ensure ventricular capture. Once capture is achieved, the current may be gradually decreased Until loss of capture, which defines the pacing current threshold. In conscious bradycardic patients, pacing is begun in the demand min ode conscious at bradyc rates slightly faster than the native rhythm and at minimal current output. rates slightly faster Gradually increase the current by 5 to 10 ma at a time until cardiac capture Gradually increase is documented, which defines the pacing threshold, or until intolerable discomfort devęlops. The finałł current output should be set at the pacing threshold or 5 tothe 10 ma fina above it.

25 The paddles - position Alternative transcutaneous pacing electode positiones Transcutaneous pacing electode positiones

26 ASSESSMENT OF SUCCESSFUL PACING Assess electrical capture by monitoring the ECG on the oscilloscope of the pacemaker unit or the cardiac monitor. Successful capture is usually characterized by a widening QRS complex and, especially, a broad T wave. The hemodynarnic response to transcutaneous pacing must also be assessed, either by palpable pulse rate, noninvasive blood pressure monitoring, or arterial catheter blood pressure monitoring.

27 COMPLICATIONS Patients who are conscious or who regain consciousness during transcutaneous pacing will experience discomfort because of pectorai muscle contractions. On higher levels of current output, the patient may experience strong, painful "knocks" on the chest. Coughing may occur due to diaphragmatic pacing. Analgesia with narcotics and sedation with benzodiazepines may be necessary to make this discomfort more tolerable until transvenous cardiac pacing can be instituted.

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