During many in- and out-of-hospital resuscitation attempts less than half the time is devoted to chest compressions. Interrupting compressions reduces myocardial perfusion and is detrimental to the ultimate success of resuscitation. Maintaining uninterrupted chest compressions must be the first priority during cardiopulmonary resuscitation.
The relative importance of chest compressions, ventilation, and defibrillation during resuscitation must be adjusted for the context of the rescue situation and the personnel available.
When an arrest is witnessed, the arrest is likely to be of cardiac (rather than respiratory) cause, and advanced care will be available within a short time, closed chest compressions alone may be as efficacious as compressions and mouth-to-mouth ventilation.
Fluctuations in intrathoracic pressure play a significant role in blood flow during most resuscitations, and the cardiac pump mechanism contributes under some circumstances.
The critical myocardial blood flow is associated with aortic "diastolic" pressure exceeding 40 mm Hg.
Cardiac output is severely depressed during cardiopulmonary resuscitation (CPR), ranging from 10% to 33% of prearrest values in experimental animals. Nearly all of the cardiac output is directed to organs above the diaphragm.
During CPR, measurement of blood gases reveals an arterial respiratory alkalosis and a venous respiratory acidosis because the arterial PCO2 is reduced and the venous PCO2 is elevated.
Exhaled end-tidal CO2 is an excellent noninvasive guide to the effectiveness of standard CPR.
Immediate defibrillation is most effective if applied within 4 to 5 minutes of collapse. Otherwise, a brief period of 2 to 3 minutes of chest compressions before defibrillation may improve survival.
Amiodarone and lidocaine are used during cardiac arrest to aid defibrillation when ventricular fibrillation is refractory to electrical countershock therapy or when fibrillation recurs following successful conversion.
Outcome studies prospectively comparing standard and high-dose epinephrine have not demonstrated conclusively that higher doses will improve survival.
Evidence currently suggests that, like other potent vasopressors, vasopressin is equivalent to but not better than epinephrine for use during CPR.
In contrast to pharmacologic therapy, 2 studies demonstrate improved neurologic outcomes when mild therapeutic hypothermia (89.6°F-93.2°F [32°C-34°C]) is induced for 12 to 24 hours in cardiac arrest survivors who remained comatose after hospital admission.
In the hospital, resuscitation from cardiac arrest depends on the rapid response of a well-trained cardiopulmonary resuscitation (CPR) team that usually includes physicians, nurses, respiratory care providers, and pharmacists. The anesthesiologist is usually a team member and frequently is expected to be the team leader. The team must be coordinated and communicate readily. The goals of published CPR guidelines and widely taught courses in basic life support (BLS), advanced cardiac life support (ACLS), and pediatric advanced life support (PALS) are to provide the knowledge base and framework for effective teamwork.1 To function within the team, the anesthesiologist must be thoroughly familiar with ACLS protocols. Team leadership requires in-depth, current knowledge of physiology, pharmacology, and alternative CPR techniques. This chapter provides the scientific background on which current CPR practice is based. It focuses exclusively on cardiac arrest. ...