The priorities of airway management during cardiopulmonary resuscitation are to minimise interruptions in chest compressions, to optimise blood flow and oxygen delivery to vital organs and to minimise delays in defibrillation if the initial rhythm is shockable. Thus, during the initial treatment of cardiac arrest, unusually, the circulation takes priority over the airway. Maintaining a patent airway will enable ventilation and oxygenation of the lungs, which becomes increasingly important after the first 3–4 minutes of sudden primary cardiac arrest (i.e. of cardiac cause). The optimal airway management strategy during cardiac arrest is uncertain. Many cardiac arrest patients are treated with multiple airway devices and this stepwise approach to airway management is difficult to study in controlled trials. The results of three recent randomised clinical trials suggest tracheal intubation should only be used in those settings with a high intubation success rate. While early oxygenation and ventilation are logically more important after asphyxial cardiac arrest existing resuscitation guidelines recommend the same sequence of actions regardless.

Introduction

Parenteral drug administration refers to drugs given by routes other than the digestive tract. The term parenteral is usually used for drugs given by injection or infusion. The enteral route usually refers to taking drugs by mouth. The common parenteral routes are listed in Table 7.1. In the USA the Food and Drug Administration (FDA) lists over 100 routes of drug administration (www.fda.gov/cder/dsm/).

Most hospital patients receive parenteral drugs at some time during their stay. Parenteral drug use is also increasingly common in the community setting (O'Hanlon, 2008). The intravenous (IV) route is associated with errors in several stages of the medication process (prescribing, preparing and administration) and this route has been associated with a higher number of errors than any other route (Hunt & Rapp, 1996; Cousins et al., 2005).

In one hospital ward study, there was at least one error made during preparation and administration in 212 (49%) out of 430 intravenous drug doses (Taxis & Barber, 2003). It is therefore important to only give drugs parenterally if it is not possible to use the simpler oral route – it is essential that the medication prescription is reviewed regularly and drug treatments changed to the safer oral route at the earliest opportunity.

Introduction

The pharmacology of resuscitation is largely based on anecdotal evidence and descriptive research rather than on objective scientific experimentation. Our understanding of the pharmacokinetics (PK) and pharmacodynamics (PD) of drugs used to resuscitate victims of cardiac arrest is also limited by ethical and experimental constraints.

Animal models of cardiac arrest and cardiopulmonary resuscitation (CPR), jointly with clinical studies, have considerably increased our understanding of the pathophysiology of cardiac arrest and significantly improved our ability to resuscitate victims of cardiac arrest. The great majority of such studies, however, were designed to address interventions to improve resuscitation rather than to investigate the pharmacological profile of drugs used in settings of cardiac arrest and reperfusion. Even less evidence is available on the PK of administration of multiple drugs, a more complex but realistic scenario. During resuscitative efforts, i.e., low flow reperfusion, significant shunting of blood to vital organs occurs. The use of vasopressors in this setting further modifies the patterns of blood flow distribution, in all likelihood affecting the PK of concomitantly administered drugs.

The time from onset of cardiopulmonary arrest until restoration of an effective spontaneous circulation is the single most important determinant of long-term survival and neurological outcome. Prompt initiation of CPR and defibrillation of ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT) are more likely to alter patient outcome than is pharmacologic management. Nevertheless, treatment with pharmacologic agents is frequently required in patients with VF or VT that is refractory to electrical shocks and in patients with asystole or pulseless electrical activity (PEA).