BASIC LIFE SUPPORT CARDIOPULMONARY RESUSCITATION AND CARDIAC ARREST: BASIC AND ADVANCED LIFE SUPPORT 219 Table 32.1: Anti-dysrhythmic drugs: the Vaughan–Williams/Singh classification Class Example Mode of action Comment I Rate-dependent block of Na� conductance a Quinidine Procainamide Disopyramide Intermediate kinetics between b and c Prolong cardiac action potential b Lidocaine Rapid dissociation from Na� Mexiletine channel Useful in ventricular tachydysrhythmias c Flecainide Slow dissociation from Na� channel Prolong His–Purkinje conduction: worsen Propafenone survival in some instances II Atenolol Beta blockers: slow pacemaker Improve survival following myocardial depolarization infarction III Amiodarone Prolong cardiac action potential Effective in supra-, as well as ventricular Sotalol tachydysrhythmias. Predispose to torsades de Dofetilide Ibutilide pointes (a form of ventricular tachycardia) IV Verapamil Calcium antagonists: block cardiac Used in prophylaxis of recurrent SVT. Largely Diltiazem voltage-dependent Ca2� conductance superseded by adenosine for treating acute attacks. Negatively inotropic Table 32.2: Drugs/ions not classified primarily as anti-dysrhythmic, but used to treat important dysrhythmias Digoxin (rapid atrial fibrillation) Atropine (symptomatic sinus bradycardia) Adenosine (supraventricular tachycardia) Adrenaline (cardiac arrest) Calcium chloride (ventricular tachycardia caused by hyperkalaemia) Magnesium chloride (ventricular fibrillation) When a person is found to have collapsed, make a quick check to ensure that no live power lines are in the immediate vicinity. Ask them, ‘Are you all right?’, and if there is no response, call for help. Do not move the patient if neck trauma is suspected. Otherwise roll them on their back (on a firm surface if possible) and loosen the clothing around the throat. Assess airway, breathing and circulation (ABC). Tilt the head and lift the chin, and sweep an index finger through the mouth to clear any obstruction (e.g. dentures). Tight-fitting dentures need not be removed and may help to maintain the mouth sealed during assisted ventilation. If the patient is not breathing spontaneously, start mouthto-mouth (or, if available, mouth-to-mask) ventilation. Inflate the lungs with two expirations (over about 2 seconds each) Unresponsive? Shout for help Open airway Not breathing normally? 2 rescue breaths Check pulse No pulse? Precordial thump if arrest witnessed 30 chest compressions 2 breaths 30 compressions Continue until breathing and pulse restored of emergency services arrive Figure 32.1: Adult basic life support.
220 CARDIAC DYSRHYTHMIAS Shockable (VF/pulseless VT) 1 Shock 150–360 J biphasic or 360 J monophasic Immediately resume: CPR 30:2 for 2 min Unresponsive? Open airway look for signs of life CPR 30:2 Until defibrillator/monitor attached Assess rhythm During CPR: • Correct reversible causes* • Check electrode position and contact • Attempt/verify: i.v. access airway and oxygen • Give uninterrupted compressions when airway secure • Give adrenaline every 3–5 mins • Consider: amiodarone, atropine, magnesium *Reversible causes Hypoxia Tension pneumothorax Hypovolaemia Cardiac tamponade Hypo/hyperkalaemia/other metabolic disturbance Toxins Hypothermia Thrombosis (coronary or pulmonary) and check that the chest falls between respirations. If available, 100% oxygen should be used. Check for a pulse by feeling carefully for the carotid or femoral artery before diagnosing cardiac arrest. If the arrest has been witnessed, administer a single thump to the precordium. If no pulse is palpable, start cardiac compression over the middle of the lower half of the sternum at a rate of 100 per minute and an excursion of 4–5 cm. Allow two breaths per 30 chest compressions. Drugs can cause fixed dilated pupils, so do not give up on this account if drug overdose is a possibility. Hypothermia is protective of tissue function, so do not abandon your efforts too readily if the patient is severely Call resuscitation team Non-shockable (pulseless electrical activity/asystole) Immediately resume: CPR 30:2 for 2 min hypothermic (e.g. after being pulled out of a freezing lake). Mobilize facilities for active warming. ADVANCED LIFE SUPPORT Figure 32.2: Adult advanced life support. (Redrawn with permission from the European Resuscitation Council Guidelines, 2005.) Basic cardiopulmonary resuscitation is continued throughout as described above, and it should not be interrupted for more than 10 seconds (except for palpation of a pulse or for administration of DC shock, when personnel apart from the operator must stand well back). ‘Advanced’ life support refers to the treatment of cardiac dysrhythmias in the setting of cardiopulmonary