The Royal Marsden Hospital Manual of Clinical Nursing Procedures - Lisa Dougherty [390]
Pharmacological support
Only a few drugs are indicated during the immediate management of a cardiac arrest and there is only limited scientific evidence supporting their use. Drugs should be considered only after a sequence of shocks has been delivered (if indicated) and chest compressions and ventilation started (Resuscitation Council 2010b). Central venous access is optimum as it allows for drugs to be delivered rapidly. However, this is dependent on the skills available. If a peripheral intravenous cannula is already in place, it should be used first (Resuscitation Council 2010b). It is also possible to administer drugs using the intraosseous route, which is used commonly in the resuscitation of children.
The drugs used in the treatment of cardiac arrest are as follows.
Adrenaline 1 mg (10 mL of a 1:10,000 solution) given intravenously. The main purpose of adrenaline is to utilize its inotropic effect to maintain coronary and cerebral perfusion during a prolonged resuscitation attempt. It is the first drug used in cardiac arrest of any aetiology. Adrenaline is included in the ALS universal algorithm (Figure 10.48), 1 mg to be given every 3–5 minutes (Resuscitation Council 2005).
Atropine is no longer recommended routinely in patients with asystole or PEA (Resuscitation Council 2010b).
Amiodarone (300 mg in 20 mL) should be considered in VF or pulseless VT. It increases the duration of the action potential in the atrial and ventricular myocardium; thus the QT interval is prolonged. In refractory VT or VF following recovery from cardiac arrest, a further 300 mg may be given followed by an infusion of 900 mg over 24 hours (Resuscitation Council 2010b). Note: lidocaine can still be considered if amiodarone is not available (Resuscitation Council 2010b).
Calcium chloride (10 mL of 10%) is only given during resuscitation when specifically indicated, that is, for the treatment of PEA caused by hyperkalaemia, hypocalcaemia or overdose of calcium channel-blocking drugs (Resuscitation Council 2010b). Although it plays a vital role in the cellular mechanisms underlying myocardial contraction, there is little data supporting any beneficial action for calcium following most cases of cardiac arrest (Resuscitation Council 2010b).
Sodium bicarbonate 8.4% is only used in prolonged cardiac arrest or according to serial blood gas analyses. Potential adverse effects of excessive sodium bicarbonate administration include hypokalaemia, exacerbation of respiratory acidosis and increased affinity of haemoglobin for oxygen. The high concentration of sodium can also exacerbate cerebral oedema. Other adverse effects are increased cardiac irritability and impaired myocardial performance. Sodium bicarbonate is usually given in 25–50 mmol aliquots and repeated as necessary. It can also be given in the special circumstances of tricyclic overdose or hyperkalaemia (Winser 2001).
Magnesium sulphate. Magnesium (4–8 mmol of 50%) should be given in cardiac arrest where there is a suspicion of hypomagnesaemia as this may precipitate refractory VF/VT (Winser 2001). It is important to recognize torsade de pointes. Many of these patients are hypomagnesaemic and/or hypokalaemic and part of effective treatment (prevention of recurrent episodes) will be giving intravenous magnesium and correction of any other electrolyte abnormality. The normal value for magnesium is 0.8–1.2 mmol/L (Wakeling and Mythen 2000).
Figure 10.48 The advanced life support algorithm for the management of cardiac arrest in adults. CPR, cardiopulmonary resuscitation; ECG, electrocardiogram; PEA, pulseless electrical activity; VF, ventricular fibrillation; VT, ventricular tachycardia.
Courtesy of Resuscitation Council (2010b).
Use prefilled syringes (mini-jets) whenever possible for speed and ease of use (Figures 10.49, 10.50, 10.51, 10.52. Drugs should be considered only after chest compressions and ventilation have been started and, where indicated, defibrillation attempted.
Figure 10.49 Mini-jet vial and administration chamber with Luer Lok connector.