Arterial carbon dioxide pressure (PaCO₂) increases 6 mm Hg during the first minute of total obstruction, with an additional 3 to 4 mm Hg increase each passing minute.⁷ If the obstruction is not corrected, the patient’s condition will continue to deteriorate resulting in cardiopulmonary arrest. This occurrence is especially tragic when the obstruction could have been corrected by simply stimulating the patient to take deep breaths or by repositioning the airway via a chin lift or jaw thrust. (These maneuvers will be discussed in more detail later.) Additional techniques include the use of a nasal or oral airway. When deciding which of these two airways to use, the PACU nurse should remember that the nasal airway is usually less stimulating and thus tolerated better in the patient emerging from general anesthesia. The nasal airway should, however, not be used with patients with known or suspected basal skull fractures, because of the possibility of inadvertent intracranial placement of the airway. Nasal airways should also not be used with patients presenting with severe coagulopathy due to the increased incidence of nasal bleeding associated with insertion of the nasal airway.⁸

If the obstruction persists, advanced airway management procedures with the esophageal-tracheal Combitube, Laryngeal Tube or King LT, laryngeal mask airway, or endotracheal tube may be indicated. Obviously, prevention of cardiopulmonary arrest is more desirable than treatment. When a cardiopulmonary arrest does occur, emergency procedures must be administered rapidly and decisively before irreversible damage occurs.⁸

Emergency equipment

The perianesthesia nurse, faced with a cardiopulmonary event, has an obvious advantage over a layman or health care provider faced with a similar event outside the hospital. This advantage is based on the numerous resources available to the PACU nurse to aid in the diagnosis and treatment of an actual or pending adverse cardiopulmonary event. These resources include the monitoring modalities, medications, essential equipment, and access to the patient’s medical history, which can give valuable insight into possible underlying causes and pathology leading up to the adverse event. Another advantage is the availability of assistance and consultation from other health care professionals.

The routine use of various monitoring modalities in the PACU is invaluable for the diagnosis of many developing patient complications that could precipitate a cardiopulmonary arrest. The use of pulse oximetry, for example, can be extremely helpful in the diagnosis of problems concerning patient oxygenation, as in the case of a progressing airway obstruction. The use of a capnograph may be helpful in the early detection of adverse respiratory events such as hypoventilation. The routine use of an ECC monitor assists the nurse in identifying life-threatening arrhythmias such as pulseless ventricular tachycardia (VT), ventricular fibrillation (VF), asystole, and pulseless electrical activity (PEA). These and other monitoring modalities provide the nurse with a more definitive means of diagnosis and opportunity for early intervention.⁸

All advanced cardiac life support equipment should be immediately available to the perianesthesia nurse. This equipment is usually found on a designated code cart or tray that is located in a designated area of the PACU. The cart should contain various emergency items including a defibrillator and monitor; emergency pharmacologic agents; equipment for circulatory, airway, and respiratory management; and specialty trays for various emergency procedures. Usually the individual PACU or health care institution establishes the general setup and contents of the cart. Each PACU nurse must be familiar with the location of the cart, its contents, and their proper use. The immediate availability of emergency equipment and pharmacologic agents is essential for successful cardiopulmonary resuscitation.

Management of cardiac arrest

Usually some event occurs that alerts the PACU nurse to the onset of a cardiopulmonary emergency. This event may be in the form of a witnessed collapse of a patient or the onset of a life-threatening arrhythmia such as pulseless VT, VF, asystole, or PEA.

Cardiopulmonary resuscitation

Chest compressions

As stated previously, cardiac arrest can be caused by four heart rhythms: VF, pulseless VT, PEA, and asystole. VF consists of disorganized electrical activity in which VT consists of organized electric activity of the ventricular myocardium. The electrical activity exhibited in these rhythms is insufficient to generate enough forward blood flow to sustain life. PEA encompasses a group of organized electrical rhythms with insufficient or absent mechanical ventricular activity. Although this rhythm may generate ventricular electrical activity on the monitor, the ventricle does not mechanically respond, resulting in the absence of a clinically detectable pulse. PEA has previously been referred to as electromechanical dissociation or nonperfusing rhythm. Asystole, also known as ventricular asystole, consists of the absence of detectable ventricular activity with or without atrial electrical activity.⁸

Ventricular fibrillation and pulseless ventricular tachycardia

During the first few minutes of witnessed VF cardiac arrest, the primary limiting factor for the delivery of oxygen to the heart and brain is blood flow and not arterial oxygen content. As a result, in the initial step of CPR, uninterrupted chest compressions take priority over positive pressure ventilation.⁸ External cardiac compression should be performed with the patient in a horizontal position on a firm surface. If a bed board is to be used, care must be taken not to delay the initiation of compressions while one is being retrieved. If the patient is on an air-filled mattress, the mattress should be deflated when performing CPR.¹⁰

To begin compressions, the rescuer should be positioned at the patient’s side. The rescuer should place the heel of one hand on the center (middle) of the chest between the patient’s nipples (the lower half of the sternum; Fig. 57-1). The heel of the rescuer’s free hand should be placed on top of the hand already positioned on the patient’s chest. The rescuer should keep the arms straight with shoulders directly over the adult patient’s sternum. The adult sternum should be depressed at least 2 inches (5 cm; Fig. 57-2). Rescuers should “push hard, push fast” at a rate of at least 100 compressions/min. Evidence appears to support the premise that this rapid compression rate effectively benefits the patient in terms of blood flow and blood pressure. Interruptions to chest compression should always be minimized to as few as possible with each interruption lasting less than 10 seconds. The chest should be allowed to completely recoil after each compression. Incomplete recoil has been associated with high intrathoracic pressures and decreased hemodynamics, including decreased coronary perfusion, cardiac index, myocardial blood flow, and cerebral perfusion. If two rescuers are present, it is recommended that they rotate giving compressions every 2 minutes. This is done to prevent rescuer fatigue, which can lead to decreased compression effectiveness such as insufficient rate, depth of compression, and incomplete recoil of the chest. It has been found that significant fatigue and shallow compressions are common after 1 minute of CPR, although the rescuer might not recognize that fatigue affecting effective compressions is present. Rescuers should consider switching roles during any intervention that is associated with appropriate interruptions in chest compressions such as defibrillation. The rescuers should strive to accomplish this switch in less than 5 seconds.⁹ The actual ratio between ventilations and chest compressions will be discussed in the third segment of the CABs, which addresses breathing.