a. Get the necessary equipment for the procedure

To perform electrocardiogram (ECG) monitoring, it is necessary to select the proper cardiac electrodes and the monitoring unit. Cardiac electrodes, or leads, pick up the electrical signal from a heart contraction and conduct it to the monitor. They are usually called chest leads (or chest electrodes or precordial leads) and consist of four parts: (1) a conducting wire coated with an electrically neutral plastic, (2) an adapter at one end of the wire that plugs into the electrocardiograph machine, (3) a different adapter at the opposite end of the wire that attaches to a patient electrode, and (4) the patient electrode (Figure 11-1, A). Conducting jelly is added to the surface of the electrode to reduce the skin’s resistance to the heart’s electrical signal. An adhesive ring holds the electrode tightly to the skin. The conducting wire snaps or clips onto the back of the electrode. Typically, three to five of these chest leads are used for a period of hours or days for basic rhythm monitoring or Holter monitoring. Typically, three or four chest leads are used for rhythm monitoring. Holter monitoring typically involves using five chest leads.

Figure 11-1 A, Close-up of the features of a prepackaged monitoring electrode or lead. B, Standard electrode placements for lead II monitoring. This results in the traditional-looking electrocardiogram waveform with upright P, QRS, and T waves. (Note: The electrodes are often labeled as right arm [RA] instead of negative pole, left arm [LA] instead of ground electrode, and left leg [LL] instead of positive electrode.)

(From Eubanks DH, Bone RC: Comprehensive respiratory care, ed 2, St Louis, 1990, Mosby.)

One of the following monitoring units must be selected, based on the patient’s situation:

3. Holter monitoring

Holter monitoring involves recording a patient’s complete ECG for 1 to 3 days through the use of a portable, battery-powered monitor. In addition, the patient keeps a diary of any episodes of chest pain, dyspnea, and so forth. The whole system includes the recording device for the patient’s ECG, a set of chest leads, a carrying bag for the recording device, and a patient activity diary (Figure 11-2).

Figure 11-2 Holter monitoring system for ambulatory electrocardiography.

(From Pagana K, Pagana TJ: Mosby’s manual of diagnostic and laboratory tests, ed 3, St Louis, 2006, Mosby.)

a. Put the equipment together and make sure that it works properly.

Connect the patient’s chest leads cable into the proper monitor. Turn on the monitor, and select the desired electrical signal from the heart (usually lead II). Confirm that the electrical signal is displayed on the monitor, and set any alarm limits.

b. Troubleshoot any problems with the equipment.

Successful ECG monitoring requires that the right electrodes be chosen, put together properly, attached to the patient as indicated, and connected to the correct ECG machine. Any errors will result in an electrical signal that is distorted or absent. Recheck all patient electrodes and wire connections if a problem is seen.

a. Get the necessary equipment for the procedure

To perform a diagnostic (also called 12-lead) ECG, get the proper cardiac electrodes and recording electrocardiogram machine. These electrodes will only be use for a few minutes as the recording of the heart’s activity is being done. They come in two sets, one for the limbs and one for the chest.

A 12-lead ECG test requires a machine capable of receiving electrical input from the four limb leads and six precordial leads (see Figures 11-3 and 11-4). The operator can manually select the lead combinations needed to get the 12 different combinations for a 12-lead ECG tracing. However, modern units do this automatically when the operator turns them on. The various ECG combinations are printed out on ECG paper. Modern units also store the patient’s information on a self-contained computer.

Figure 11-3 Limb electrodes or leads properly placed on all four of the patient’s limbs. Make sure that the right leg lead is placed on the right leg, the right arm lead is placed on the right arm, and so forth. The electrode cables are then plugged into the electrocardiograph machine to record the ECG tracings.

(From Eubanks DH, Bone RC: Comprehensive respiratory care, ed 2, St Louis, 1990, Mosby.)

Figure 11-4 Proper placement of the six precordial leads. (See Table 10-1 for a description of the locations.)

(From Eubanks DH, Bone RC: Comprehensive respiratory care, ed 2, St Louis, 1990, Mosby.)

b. Put the equipment together and make sure that it works properly

The limb leads come as a group of four with one for each arm and leg (Figure 11-3). Precordial leads came in a group of six and are placed on the chest in the positions shown in Figure 11-4. A conducting and adhesive jelly is used to reduce the skin’s resistance and to hold the lead in place. The limb leads are longer, and they may need to be held in place by a rubber strap.

c. Troubleshoot any problems with the equipment

Successful ECG monitoring requires that the right electrodes be chosen, put together properly, attached to the patient as indicated, and connected to the correct ECG machine. Any errors will result in an electrical signal that is distorted or absent. With all types of cardiac leads, bad skin contact, dried conducting jelly, or a disconnected wire results in a distorted or absent electrical signal. Recheck all patient electrodes and wire connections if a problem is seen.

a. Review cardiac monitoring data in the patient record (Code: IIB8) [Difficulty: ELE: R; WRE: Ap]

Review the chart of any patient admitted with a significant cardiopulmonary problem for a record of previous cardiac monitoring. Look for a record of rhythm disturbances.

b. Recommend cardiac monitoring (Code: IC9) [Difficulty: ELE: R, Ap; WRE: An]

Recommend cardiac monitoring in any patient with a significant cardiopulmonary problem. This could include, but is not limited to, congestive heart failure, previous myocardial infarction, suspicion of current myocardial infarction, pulmonary embolism, pneumonia, or other problem that could result in serious hypoxemia.

c. Monitor the cardiac rhythm to evaluate the patient’s response to respiratory care (Code: IIIE6) [Difficulty: ELE: R, Ap; WRE: An]

Many hospitalized patients have serious cardiopulmonary problems. The patient may receive supplemental oxygen or inhaled bronchodilator medications. If a possibility exists that the patient will experience significant changes in heart rate or rhythm, he or she should be continuously monitored. This could include patients with serious cardiopulmonary problems, as listed previously. In addition, it could be a patient with an electrolyte disturbance or who is receiving replacement electrolytes intravenously, especially potassium. A bedside rhythm monitoring unit should have an oscilloscope for viewing the rhythm and additional features for counting the heart rate, setting high and low heart rate alarms, and recording the rhythm on standard ECG paper for a permanent record.

The most common chest electrode pattern used for rhythm monitoring is called lead II. The three chest electrodes are placed as shown in Figure 11-1, B. The negative (right arm, RA) electrode is on the right upper chest. The positive (left leg, LL) electrode is placed on the left lateral chest. The ground (left arm, LA) electrode is placed on the left upper chest. With this electrode configuration, known as the Einthoven triangle, the heart’s electrical signal is followed as it flows from the right atrium to the left ventricle. This results in the so-called normal ECG tracing with upright P, R, and T waves, as shown in Figures 11-5 and 11-6. Table 11-1 shows the sequential electrical events of the normal cardiac rhythm that correspond with those in Figure 11-5.

Figure 11-5 Sequence of electrical events of the cardiac cycle during normal sinus rhythm. (See Table 10-2 for the description of each event.)

(From Phillips RE, Feeney MK: The cardiac rhythms: a systematic approach to interpretation, ed 3, Philadelphia, 1990, Saunders.)

Figure 11-6 Timing of the electrical events of the cardiac cycle during normal sinus rhythm.

(From Spearman CB, Sheldon RL, Egan DF: Egan’s fundamentals of respiratory therapy, ed 4, St Louis, 1982, Mosby.)

TABLE 11-1 Electrophysiologic Events Represented by the Electrocardiogram Sequential Electrical Events Electrocardiographic of the Cardiac Cycle Representation

From Phillips RE, Feeney MK: The cardiac rhythms: systematic approach to interpretation, ed 3, Philadelphia, 1990, WB Saunders.

Holter monitoring is done to evaluate noncritical, home care patients with a suspected cardiac problem. Because the patient will be mobile for at least 1 day, the limb leads are placed on the upper and lower chest area. Precordial leads are placed normally. The patient wears a tight-fitting undershirt or netlike dressing to keep the leads in place. The patient cannot bathe while the leads are on.

a. Review electrocardiogram data in the patient record (Code: IB8) [Difficulty: ELE: R; WRE: Ap]

Review the chart of any patient admitted with a significant cardiac problem for a record of a previous electrocardiogram. Look for a record of rhythm disturbances or diagnosis of the problem.

b. Recommend an electrocardiogram to obtain additional data (Code: IC9) [Difficulty: ELE: R, Ap; WRE: An]

A diagnostic electrocardiogram (also called a 12-lead ECG) test is indicated if the patient is suspected of having cardiac problems. Symptoms such as syncope, angina pectoris, sudden crushing chest pain, shortness of breath, or unstable heart rate and blood pressure point to a heart problem. Growing evidence indicates that men and women have different signs and symptoms during an acute myocardial infarction (AMI or MI). Men tend to have crushing central chest pain that may radiate down the left arm or the left side of the neck, diaphoresis, cold extremities, shortness of breath, and a feeling of impending doom. Women tend to experience pain in the lower back and the abdominal area. A diagnostic ECG is indicated to document the nature of the cardiac problem or rule out the heart as a source of the symptoms.

c. Perform a diagnostic electrocardiogram (Code: IB9a) [Difficulty: ELE: R, WRE: Ap, An]

The 12-lead ECG involves the use of an electrocardiograph machine with heat-sensitive ECG recording paper, four limb leads, and six precordial leads (see Figures 11-3 and 11-4). Table 11-2 describes the locations of the precordial leads and the positive and negative electrode combinations that are used to record the heart’s electrical signal through the 12 different leads. Each lead individually records the heart’s electrical activity, but it does so from a different position in relation to the heart. These 12 leads give the physician a three-dimensional impression of how the cardiac conduction system and the myocardium are functioning. Abnormal functioning can be diagnosed. Review the normal anatomy and physiology of the heart and its conduction system, if necessary.

Clinical experience is important in performing a diagnostic ECG. Improper placement of the precordial or limb leads can easily result in a misleading ECG tracing and a misdiagnosis. For example, reversing the arm leads causes the QRS to be reversed in lead I. Technical errors in grounding the patient and not keeping the patient still during the ECG also result in useless tracings because of electrical interference and an unstable baseline.

a. Get the necessary equipment for the procedure

The first consideration when deciding which manual resuscitator to select is the size of the patient. Although the volume of the reservoir bag and the tidal volume expelled from it vary among the types of bags, three basic sizes are available. An infant or newborn unit typically has a reservoir bag volume of about 250 mL. A pediatric unit usually has a reservoir bag volume of about 250 to 500 mL, and an adult unit typically has a reservoir bag volume of 1500 to 2000 mL. In addition to all of these reusable units, a number of disposable units are thrown away after one patient use. They also come in comparable infant, pediatric, and adult reservoir bag volumes.

Any unit should deliver 100% oxygen at the flow rate of 15 L/min. An oxygen reservoir system must be added to the basic unit to achieve these oxygen percentages. The valve to the patient must be clearable within 20 seconds if it becomes fouled by vomitus, sputum, or blood.

Neonatal and pediatric units must have a pressure release (pop-off) valve that opens at 40 cm H₂O pressure. The pressure may be adjustable. If an adult unit has a pressure release valve, it must have an override system that is easy to operate.

b. Put the equipment together and make sure that it works properly

Figure 11-7 shows line drawings of a complete set of Laerdal infant, pediatric, and adult manual resuscitators. The following steps should be taken when the function of a manual resuscitator is evaluated:

Figure 11-7 A, Cutaway drawings of a resuscitation bag showing its features and how the one-way valves open and close during exhalation and inhalation. Note that during exhalation, the patient’s breath is vented to the room and supplemental oxygen is drawn from the reservoir bag into the main bag. To deliver a breath to the patient, the operator squeezes the main bag. This opens the valve to the patient and closes the valve from the reservoir bag. B, Photograph showing an adult, child, and infant resuscitation bag with attached face mask and oxygen reservoir bag. These features are found on all modern units: a self-filling main bag, exhalation valve that does not jam at an oxygen flow of 15 L/min or in subfreezing temperatures (it must be clearable of debris within 20 seconds), intake valve for adding draw room air or supplemental oxygen into the reservoir bag, transparent mask that easily conforms to the patient’s face, pressure relief (pop-off) valve that is set to open at 40 cm water, standard 15-mm inner diameter/22-mm outer diameter connector for the endotracheal tube or face mask, and an oxygen enrichment/reservoir system. In addition, some units have an adjustable positive end-expiratory pressure valve (not shown) attached to the exhalation valve.

(A from Cairo JM, Pilbeam SP: Mosby’s respiratory care equipment, ed 8, St Louis, 2010, Mosby. B courtesy Laerdal Medical, Wappingers Falls, NY.)

c. Troubleshoot any problems with the equipment

Check for a reversed or improperly seated one-way valve (spring-loaded, duckbill, or leaf type) if the gas does not enter or exit the unit as it should. In clinical use, mucus, vomitus, and blood can foul the expiratory one-way valve system. By regulation, the valve must be clearable within 20 seconds. Do this by disconnecting the unit from the patient, aiming the adapter into a neutral area, and squeezing the bag to blow out the obstruction. Replace a unit that cannot be promptly cleared of any debris.

a. Get the necessary equipment for the procedure

The following are important considerations when selecting the best mouth-to-valve device (also called a mouth-to-mask device or pocket mask) for the victim:

b. Put the equipment together and make sure that it works properly

Mouth-to-valve resuscitators are relatively simple devices. Most have only two or three pieces: a face mask, a mouthpiece with a one-way valve, and possibly an oxygen T-piece (Figure 11-8). The “male” and “female” connections are designed to fit together in only one way. When they are properly assembled, no air should leak out when the breath is delivered to the victim.

Figure 11-8 Proper positioning to use a mouth-to-valve mask resuscitator. The top rescuer has added supplemental oxygen to the device. The bottom rescuer is ventilating without the use of added oxygen.

(Courtesy Laerdal Medical Corporation, Wappingers Falls, NY.)

c. Troubleshoot any problems with the equipment

If the breath cannot be delivered, check the one-way valve to make sure that it has not been put together backward. Reverse it, if necessary, and ventilate the victim’s airway. Keep the oxygen nipple on the mask or T-piece capped off if it is not being used. Air will leak out during the delivered breath if the cap is left off the nipple.

a. Establish that the patient is unresponsive and needs cardiopulmonary resuscitation

Observing a patient who appears to be dead does not prove that the patient needs CPR. Clinical death must be proved before CPR is begun. Adults should be tapped or gently shaken while you shout, “Are you okay?” Infants should have the bottom of their feet gently slapped while you shout, “Wake up!” The rescuer also can clap his or her hands together loudly to wake a sleeping infant. CPR should never be started on a person who does not need it.

b. Call out for help

Call out for help if the victim does not respond to any attempts at arousal. The second rescuer should be told to call in the cardiac arrest team. Many hospitals have a cardiac arrest button in each patient’s room. If this is the case, the first rescuer can push the button while calling out for help. Dial 911 if the victim is found at home.

c. Open the airway

The head-tilt/chin-lift maneuver is the procedure of choice for opening the airways of all victims except those with a known or suspected cervical (neck) spine injury. The victim is gently positioned on his or her back. In an adult, the head is firmly pushed back with one hand, and the jaw is pulled upward with the fingers of the other hand (Figure 11-9). In an infant, it is not necessary to tilt the head back beyond a neutral position. Children may need to have the head pushed back slightly beyond neutral.

Figure 11-9 Opening the adult’s airway. Top, Airway obstruction produced by the tongue and epiglottis. Bottom, Relief by head-tilt/chin-lift method.

(From Standards and guidelines for cardiopulmonary resuscitation [CPR] and emergency cardiac care [ECC], JAMA 268:2186, 1992.) Copyright © 1992, American Medical Association. All rights reserved.

The jaw-thrust maneuver is the procedure of choice for opening the airway of all victims with a known or suspected cervical spine injury. The rescuer’s elbows are rested on the ground, and the hands are placed on either side of the victim’s jaw. Lifting of the jaw usually opens the airway and eliminates the need to tilt the head back. See Figure 11-10 for the adult maneuver.

Figure 11-10 Opening the adult’s airway by the jaw-thrust method.

(From Watson MA: Cardiopulmonary resuscitation. In: Barnes TA, editor: Respiratory care practice, St Louis, 1988, Mosby.)

Any obstruction that can be seen in the mouth or throat should be removed. The cross-finger technique can be used to open the mouth wide enough so that a finger or suction device can be inserted to remove a blockage (Figure 11-11). An oral airway should be used only in an unconscious patient to keep the tongue from falling back and blocking the airway.

Figure 11-11 The cross-finger method of opening the victim’s mouth to look for an obstruction.

(From Watson MA: Cardiopulmonary resuscitation. In: Barnes TA, editor: Respiratory care practice, St Louis, 1988, Mosby.)

d. Determine that the patient is not breathing

The rescuer places his or her face close to the victim’s face to look for rising and falling of the chest, listen for victim’s air movement, and feel any air movement from the victim’s breathing (Figure 11-12). The entire procedure should not take longer than 10 seconds.

Figure 11-12 Determining breathlessness by looking, listening, and feeling.

(From Standards and guidelines for cardiopulmonary resuscitation [CPR] and emergency cardiac care [ECC], JAMA 268:2187, 1992.) Copyright © 1992, American Medical Association. All rights reserved.

e. Ventilate the patient

1. Mouth-to-mouth breathing

The first rescuer should begin mouth-to-mouth breathing as soon as possible if no spontaneous breathing by the victim occurs once the airway is opened. No matter the age of the victim, an effective seal must be present between the rescuer and the victim. The adult victim’s nose must be pinched closed; often the rescuer’s cheek can block the infant’s nose. The rescuer’s mouth can cover both the nose and mouth of an infant. Alternative methods include mouth-to-nose and mouth-to-stoma ventilation (Figure 11-13).

Figure 11-13 A, Adult mouth-to-mouth, mouth-to-nose (B), and mouth-to-stoma (C) ventilation.

(From Standards and guidelines for cardiopulmonary resuscitation [CPR] and emergency cardiac care [ECC], JAMA 268:2188, 1992.) Copyright © 1992, American Medical Association. All rights reserved.

In an adult, two breaths large enough to raise the victim’s chest should be given. An adequate volume of 500 to 600 mL may be given. Blow into the victim’s mouth for more than 1 second. This is to ensure a large enough volume without having to use much pressure. Keeping the ventilating pressure as low as possible minimizes the risk of forcing air into the stomach. Ensure that the victim exhales completely by watching the chest fall and feeling the air escape against your cheek. Rescue breathing should be performed at a rate of 10 to 12 times per minute (every 4 to 5 seconds) if the victim has a pulse but is apneic.

A child should be given two breaths large enough to raise the victim’s chest. A child obviously needs less volume than an adult. All of the same considerations apply as for the adult. Rescue breathing should be performed at a rate of 12 to 20 per minute (every 3 to 5 seconds) in an infant and a child. A newly born infant should be ventilated at a rate of 40 to 60 per minute.

If the victim’s airway cannot be ventilated, reposition the head and attempt to ventilate again. Failure to ventilate a second time means that the victim has an obstructed airway. The following steps should be taken:

a. Unconscious adult obstructed airway maneuvers

1. Position. Place the victim on his or her back.

2. Heimlich maneuver. Perform the Heimlich maneuver (also known as abdominal thrusts) several times, if needed, by kneeling astride the victim, placing the heel of one hand midline on the abdomen slightly above the navel, but well below the xiphoid process. The other hand is placed on top, and both are quickly thrust upward toward the chest (Figure 11-14). The rescuer can also perform chest thrusts on the markedly obese or obviously pregnant victim. The rescuer’s hands should be placed on the lower half of the sternum as with cardiac compressions. Several compressions should be performed slowly but similarly to a cardiac compression.

3. Finger sweep. Attempt to clear out any foreign body with a finger sweep. Only attempt this when solid material can be seen in the throat of an unconscious patient. First, grasp the victim’s tongue and jaw between your thumb and fingers, and lift the jaw open. Next, insert the index finger of the other hand along the inside of the victim’s cheek and down the back of the throat so as to hook and remove food, gum, dentures, and so on.

b. Unconscious child (1 year old and older) obstructed airway maneuvers

1. Position. Same as the adult position previously described.

2. Heimlich maneuver. Same as the adult maneuver but with up to five thrusts performed if needed. Chest thrusts are not used.

3. Finger sweep. Only attempt this when solid material can be seen in the throat of an unconscious patient. Remember that blindly inserting the index finger may push a foreign body farther down the throat.

c. Unconscious infant obstructed airway maneuver

1. Position. The infant is straddled over the rescuer’s forearm. The infant’s jaw and head are held by the rescuer’s hand. The infant’s head should be lower than the body. Five firm back blows are delivered between the shoulder blades with the heel of the rescuer’s other hand (Figure 11-15).

2. Heimlich maneuver. The infant is sandwiched by the rescuer’s other arm, and the head and body are supported and turned to a supine position. The head should remain lower than the body. Five chest thrusts are performed in the same location and manner as cardiac compressions but at a slower rate. These steps can be done by placing the infant on the rescuer’s lap.

3. Finger sweep. Same as finger sweep in the unconscious child, mentioned previously.

Figure 11-14 Administering the Heimlich maneuver to an unconscious adult victim of an airway obstruction.

(From Standards and guidelines for cardiopulmonary resuscitation [CPR] and emergency cardiac care [ECC], JAMA 268:2193, 1992.) Copyright © 1992, American Medical Association. All rights reserved.

Figure 11-15 Administering (A) back blows and (B) chest thrusts to an infant victim of an obstructed airway.

(From Standards and guidelines for cardiopulmonary resuscitation [CPR] and emergency cardiac care [ECC], JAMA 268:2258, 1992.) Copyright © 1992, American Medical Association. All rights reserved.

2. Manual resuscitator (bag-valve)

A manual resuscitator should be used during hospital-based CPR as soon as one is available. The resuscitation mask must be held to the victim’s face so that no air leak occurs during the forced inspiration (Figure 11-16). An assistant can hold the mask tightly to the face so that the rescuer who is pumping the resuscitation bag can use both hands. This has been shown to produce a larger tidal volume. If the victim’s airway contains an endotracheal tube or tracheostomy tube, the expiratory valve adapter fits directly over the tube adapter. Rescue breathing continues with the previously mentioned considerations for volume and rate. After an adult victim has had an endotracheal tube placed, the tidal volume goal is 500 to 600 mL over a 1-second period to produce a visible chest rise.

Figure 11-16 Ventilation of an adult with a manual resuscitation bag and mask.

(From Eubanks DH, Bone RC: Comprehensive respiratory care, ed 2, St Louis, 1990, Mosby.)

f. Add supplemental oxygen (ELE code: IIID6) [Difficulty: ELE: R, Ap, An]

The victim should be given 100% oxygen as soon as possible. There is no contraindication for giving pure oxygen during a resuscitation effort. This can be done easily if a manual resuscitator is used to ventilate the victim. All modern units are capable of delivering 100% oxygen when receiving an oxygen flow of at least 10 to 12 liters/minute and a reservoir is added.

g. Determine pulselessness

The carotid pulse is felt for in all victims except children younger than 1 year. The carotid pulse is found by gently feeling with two or three fingers in the groove between the larynx and the sternocleidomastoid muscle on either side of the neck (Figure 11-17). Check for 5 to 10 seconds to be sure that the victim is pulseless and not just bradycardic. In addition, check for other signs of circulation such as spontaneous breathing, coughing, and movement. An infant younger than 1 year should have the pulse felt in the brachial artery; the carotid artery is difficult to find in such young children because they have short, chubby necks.

Figure 11-17 Determining pulselessness by checking the carotid pulse of an adult.

(From Standards and guidelines for cardiopulmonary resuscitation [CPR] and emergency cardiac care [ECC], JAMA 268:2189, 1992.) Copyright © 1992, American Medical Association. All rights reserved.

The femoral pulse can be felt for as an alternative site in victims in the hospital who are wearing few clothes. Once the CPR team has arrived and two-person CPR is instituted, the femoral pulse may be most accessible for monitoring the pulse and the effectiveness of the chest compressions.

h. Perform external chest compressions

The absence of a palpable pulse confirms a cardiac arrest. Blood must be pumped by external chest compressions of the heart. The victim must be supine on a hard surface. A CPR backboard is placed behind a victim who is in bed.

In adults and large children or those older than 8 years, the heel of the rescuer’s hand is placed over the lower half of the sternum. This is found by placing the middle finger of one hand in the notch where the ribs meet the sternum, placing the index finger next to it, and placing the other hand next to the finger. The first hand is placed over it, the elbows are locked, and the shoulders are directly over the hands. This creates the most efficient pumping action (Figure 11-18). The rescuer pivots from the hips, with half of the time spent pumping down and half of the time releasing pressure. The hands should always touch the victim’s chest. The sternum must be compressed 4 to 5 cm (1.5 to 2.0 inches) in an adult at a rate of 100 compressions per minute for an actual rate of more than 80 per minute.

Figure 11-18 Cardiac compression of an adult. A, Locate tip of xiphoid process. B, Place two fingertips at xiphoid process. C, Place palm of other hand on sternum next to fingers. D, Arm and body positions for cardiac compression.

(From Barnes TA, editor: Respiratory care practice, St Louis, 1988, Mosby.)

In a child 8 years old or younger, hand position is found as in the adult. The child’s sternum must be compressed with one hand to a depth of 2.5 to 4 cm (1 to 1.5 inches). Half of the time should be spent on compression and half on relaxation. The rate should be 100 compressions per minute for a rate of more than 80 per minute between ventilations.

In newly born infants and older infants, the preferred method of chest compressions is called the two thumbs–encircling hands technique (Figure 11-19). This method works best when a second rescuer can ventilate the infant. It also is acceptable to compress with two or three fingers placed over the middle of the sternum one finger’s width below an imaginary line drawn between the nipples (Figure 11-20). This method is easier when one rescuer must provide ventilations and compressions. In either case, the child’s sternum must be compressed to a depth of 1.3 to 2.5 cm (0.5 to 1 in.). Half the time should be spent on compression and half the time on relaxation. A newly born infant should have a rate of at least 120 compressions per minute to achieve an actual rate of 90 per minute.

Figure 11-19 The preferred way to provide chest compressions on a newly born neonate is called two thumbs-encircling hands. This method is best when one rescuer can provide chest compressions and another can ventilate the patient. The two thumbs are placed over the sternum and below an imaginary line between the nipples. If the newborn is very small, the two thumbs can overlap.

(From Wilkins RL, Stoller JK, Kacmarek RM: Egan’s fundamentals of respiratory care, ed 9, St. Louis, 2009, Mosby.)

Figure 11-20 Locating the proper finger position for chest compressions on an infant.

(From Standards and guidelines for cardiopulmonary resuscitation [CPR] and emergency cardiac care [ECC], JAMA 268:2256, 1992.) Copyright © 1992, American Medical Association. All rights reserved.)

The steps for one- and two-person hospital-based CPR follow.

a. Interpret the results of a diagnostic electrocardiogram (Code: IB10a) [Difficulty: ELE: R, Ap; WRE: An]

1. ECG paper

Before discussing 12-lead ECG interpretation, it is important to understand how ECG paper is designed so that the heart’s electrical signal traced on it can be understood. This special paper is heat sensitive and, after exiting the ECG machine, shows a black line from the heated stylus. Figure 11-21 shows the grid markings on the paper and how to interpret the ECG tracing for voltage and time. Each large square box is 5 mm in height and represents 0.5 millivolts (mV) of the heart’s electrical force. The large square box is divided into five smaller boxes that are 1 mm in height and represent 0.1 mV. Timing of the ECG tracing is determined by the speed with which the paper passes under the heated stylus. Normally, this is 25 mm/sec. At this speed, each large square box is 20 seconds, and each of the five small boxes is 0.04 seconds; 300 large boxes compose 1 minute’s time (0.20 seconds ¥ 300 = 60 seconds).

Figure 11-21 ECG paper with added details on how to interpret time and voltage.

(From Patel JM, McGowan SG, Moody LA: Arrhythmias: detection, treatment, and cardiac drugs, Philadelphia, 1989, Saunders.)

The following 10 features should be examined and time interval measured in every ECG:

1. Heart rate

2. Rhythm

3. P wave

4. PR interval

5. QRS interval

6. QRS complex

7. ST segment

8. T wave

9. QT interval

10. U wave

The systematic evaluation of these factors usually results in a clear understanding of the patient’s cardiac function. All of these factors are discussed and illustrated in this chapter. Before evaluating the ECG paper tracing for possible cardiac arrhythmias, first rule out any artifacts and determine the patient’s heart rate.

3. Heart rate

The heart rate can be most accurately found by counting it for 1 minute; however, this time-consuming method is not always practical. An approximate heart rate can be quickly found. First, find a heartbeat tracing in which the R wave is on a heavy vertical line. Then count the number of large boxes between this first R wave and the next R wave. Approximate heart rates can be estimated as follows:

• Two large boxes = 150 beats/min (300 divided by 2)

• Three large boxes = 100 beats/min (300 divided by 3)

• Four large boxes = 75 beats/min (300 divided by 4)

• Five large boxes = 60 beats/min (300 divided by 5)

• Six large boxes = 50 beats/min (300 divided by 6)

For example, in Figure 11-22, during inspiration there are three large boxes between R waves for a heart rate of about 100/minute. During exhalation there are four large boxes between R waves for a heart rate of about 75/minute.

Figure 11-22 Sinus arrhythmia showing slightly increased heart rate during inspiration and slightly decreased heart rate during exhalation.

(From Goldberger AL: Clinical electrocardiography: a simplified approach, ed 7, St Louis, 2006, Mosby.)

a. Normal sinus rhythm.

Obviously, the normal cardiac rhythm must be understood to distinguish it from the abnormal rhythms. The normal adult’s cardiac rhythm is usually called normal sinus rhythm (NSR) and has these characteristics:

• Heart rate between 60 and 100 beats/min while at rest

• Rhythm that varies by no more than ± 10% between QRS complexes

• P wave before every QRS complex and upright in lead II

• A QRS complex follows every P wave

• Proper timing of the components of the ECG rhythm

Figure 11-6 shows the timing of the components of a normal sinus rhythm.

b. Abnormal cardiac rhythms.

The following list of abnormal cardiac rhythms (usually called arrhythmias or dysrhythmias) includes many of those that are commonly encountered in clinical practice. It is beyond the scope of this text to discuss all possible arrhythmias. Instead, those that are either frequently seen or dangerous are described. Each of the following cardiac irregularities is (1) defined, (2) exemplified, (3) described, (4) discussed in terms of its clinical significance, and (e) accompanied by a treatment (if any) description.

1. Arrhythmias with a sinoatrial node origin. The following three arrhythmias all originate from the sinoatrial (SA) node. The electrical signal follows the normal pathway and results in contraction of both atria and ventricles, as expected. They are distinguished from NSR by the differences in rate and regularity of the impulses.

a. Sinus arrhythmia. This arrhythmia is characterized by normal complexes but is a heart rate that varies with the respiratory cycle (see Figure 11-22 for an example). Notice how the QRS complexes are closer together on inspiration than on expiration. This is because the increased venous return to the heart during inspiration causes the heart to fill more quickly, so that the pulse rate quickens. The opposite rhythm effect is sometimes seen with a patient on a mechanical ventilator. No cardiac treatment is needed. Every attempt should be made to lower the intrathoracic pressure in the mechanically ventilated patient.

b. Sinus tachycardia. Sinus tachycardia in the adult is defined as a heart rate of more than 100 beats/min while at rest. All complexes are normal, and the rate is seldom more than 140 (see Figure 11-23 for an example). Causes include caffeine, anxiety, fever, pain, or hypotension. Correction of the problem results in the heart rate decreasing to the normal range. Cardiac drugs are not needed.

c. Sinus bradycardia. Sinus bradycardia is defined as a heart rate of less than 60 beats/min while at rest (Figure 11-24). All complexes remain normal. This is commonly seen in well-trained athletes during rest and in patients receiving digitalis or morphine. Cardiac drugs are not needed.

Figure 11-23 Sinus tachycardia.

(From Goldberger AL: Clinical electrocardiography: a simplified approach, ed 7, St Louis, 2006, Mosby.)

Figure 11-24 Sinus bradycardia.

(From Golderberger AL: Clinical electrocardiography: a simplified approach, ed 7, St Louis, 2006, Mosby.)

If sinus bradycardia is associated with a myocardial infarct, it may result in fainting or congestive heart failure (pulmonary edema). The patient must be treated not only for the heart attack but also to increase the heart rate. Atropine is the first medication given to speed the heart rate. A pacemaker is needed if the patient does not respond to medications and continues to have symptoms.

2. Arrhythmias with an abnormal atrial origin. The following three arrhythmias originate in either one or both atria from a source other than the SA node. The electrical signal travels through the atria, which contracts them. It then moves on to the atrioventricular (AV) node and the ventricles, which contract normally. All of these arrhythmias result in faster than normal atrial contraction and often in a faster than normal ventricular contraction.

a. Paroxysmal atrial tachycardia. Paroxysmal atrial tachycardia (PAT) (also known as paroxysmal supraventricular tachycardia [PSVT]) is a series of three or more premature atrial contractions. It is characterized by a heart rate between 140 and 250 beats/min with an average rate of 180. The ECG tracing will show a normal QRS complex after each P wave (Figure 11-25). Notice the abnormal origin of the P wave seen during the PAT episode. The recommended term for any abnormal origin to a heartbeat is focus. The term foci refers to more than one abnormal site to a heartbeat.

Figure 11-25 A short run of paroxysmal trial tachycardia (PAT). Although a short run is probably not dangerous, a long run should be treated.

(From Wilkins RL, Dexter JR, Heuer AJ: Clinical assessment in respiratory care, ed 6, St Louis, 2010, Mosby.)

Patients with long runs of PAT usually complain of a sudden onset of pounding or fluttering in the chest. This is often associated with breathlessness, weakness, and angina pectoris in patients with coronary artery disease. Because of these problems, long runs of PAT must be treated. Treatment usually progresses in the following sequence: (1) give a sedative, (2) stimulate the vagus nerve by rubbing the carotid sinus (Figure 11-26), (3) give propranolol (Inderal) or a similar medication, and (4) perform synchronized cardioversion. (This last procedure is described in Chapter 18.) Obviously, if the patient responds to one treatment method, no need exists to go on to the next.

b. Atrial flutter. Atrial flutter is characterized by a single, fast, abnormal atrial focus that fires at a rate of about 250 to 350 beats/min. This rate is so fast that the AV node does not pass all of them along to the ventricles. On an ECG, a ratio between the fast flutter waves and the QRS complex is seen. Usually this ratio is 2 : 1, but it may be 3 : 1, 4 : 1, or more. (See Figure 11-26 for several example ECG tracings of atrial flutter.) As with PAT, the fast ventricular rate found in atrial flutter is not well tolerated. An attempt must be made to suppress the abnormally fast atrial focus. Carotid sinus pressure, digoxin (Lanoxin), and synchronized cardioversion are the preferred treatments to slow the heart rate.

c. Atrial fibrillation. This condition is identified by the variably shaped fibrillation waves and the irregular spacings between the QRS complexes. Each focus is seen on the ECG as a separately shaped wave. As with atrial flutter, the AV node does not pass the electrical current from each fibrillation wave through to the ventricles. However, with atrial fibrillation, the ratio is not set, and variable spacing is seen between the QRS complexes and an inconsistent rate (Figure 11-27). Patients with atrial fibrillation do not completely empty their atria. Often this results in the formation of blood clots that become pulmonary or cerebral emboli. Digitalis and synchronized cardioversion usually are effective treatments. Heparin or Coumadin may be added to prolong the blood-clotting time.

3. Arrhythmias with an atrioventricular node origin. Both of the following arrhythmias originate in an AV node. The patient may or may not have a normal SA node, atria, and ventricles.

a. Atrioventricular block. AV block is most commonly caused by digitalis toxicity, arteriosclerosis, or myocardial infarction. The latter two may result in scarring, inflammation, or edema. These slow or prevent the transmission of the electrical signal from the SA node through the AV node and to the ventricles. First-degree AV block is seen with an increased PR interval of at least 0.20 seconds. Each P wave is followed by a normal QRS complex (Figure 11-28). It does not require any treatment. Second-degree AV block results in some P waves being blocked out completely with no ventricular response. This more serious condition comes in two different variations. Wenckebach (also known as Mobitz type I) is characterized by a progressively longer PR interval until a P wave is not conducted through at all. Then the cycle starts over again and continues to repeat itself. (See Figure 11-29 for examples.) Medications such as atropine or isoproterenol may be used to increase the heart rate. Mobitz type II is seen on the ECG as a rhythm in which the PR interval is normal for those that result in a QRS complex, but some P waves are completely blocked (Figure 11-30). The ratio between those P waves that conduct and those that are blocked off may be 2 : 1, 3 : 1, or 4 : 1. Mobitz type II is a sign of severe conduction-system disease. The usual treatment is to place a cardiac pacemaker into the patient. Third-degree AV block also is known as complete heart block (Figure 11-31). No P waves are conducted through to the ventricles. The ventricles beat about 40 times per minute based on the intrinsic rate of the bundle of His and Purkinje fibers. Obviously, a heartbeat this slow is not normal or healthy. Patients have no stamina and frequently faint. A cardiac pacemaker must be placed into these patients.

b. Junctional premature beats. A junctional premature beat is also known as a premature AV nodal contraction (PNC), nodal beat, or junctional beat (Figure 11-32). This arrhythmia involves the AV node sending out a premature electrical signal and becoming the primary pacemaker instead of the SA node. The ventricles contract normally with the expected QRS complex.

4. Arrhythmias with a ventricular origin myocardial infarction. A myocardial infarction (MI) or acute myocardial infarction (AMI), commonly known as a heart attack, is an occlusion of a coronary artery that results in the death of some segment of the heart muscle. Often the patient with partial or complete coronary artery occlusion has symptoms of shortness of breath, central chest pain, pain that radiates down the left arm or up the left side of the neck, or a feeling of stomach upset. If an ECG is performed, it may show ST-segment depression as a sign of myocardial hypoxia (Figure 11-33). If the patient is properly treated, an MI may be prevented by opening the blocked artery.

Figure 11-26 Two examples of atrial flutter. A, Note the variable appearance of the flutter waves in different leads. This example shows a 2 : 1 ratio between atrial contractions and ventricular contractions. B, This shows how the ventricular rate is decreased after carotid sinus pressure is applied. The “F” letterings show flutter waves from a single focus. The “R” letterings mark R waves when the electrical signal traveled through the atrioventricular node to stimulate the ventricles.

(From Goldberger AL: Clinical electrocardiography: a simplified approach, ed 7, St Louis, 2006, Mosby.)

Figure 11-27 Atrial fibrillation. Note the variable shapes to the fibrillation waves, indicating their different origins. Also note how the distances between the R waves change considerably. This depends on when an electrical signal from the atria passes through the atrioventricular node to the ventricles.

(From Wilkins RL, Dexter JR, Heuer AJ: Clinical assessment in respiratory care, ed 6, St Louis, 2010, Mosby.)

Figure 11-28 First-degree atrioventricular block results in a PR interval that is longer than the normal interval of five small blocks or 20 seconds. ECG strip A shows a PR interval of 0.30 seconds. ECG strip B shows a PR interval of 0.24 seconds.

(A From Conover MB: Understanding electrocardiography, arrhythmias, and the 12-lead ECG, ed 4, St Louis, 1984, Mosby. B From Conover MB: Understanding electrocardiography, ed 8, St Louis, 2003, Mosby.)

Figure 11-29 Two examples of Wenckebach (Mobitz type I) second-degree atrioventricular block. Note how the PR interval progressively lengthens with each beat until one P wave is not conducted through at all. The cycle then repeats itself.

(From Goldberger AL: Clinical electrocardiography: a simplified approach, ed 7, St Louis, 2006, Mosby.)

Figure 11-30 Mobitz type II second-degree heart block. Note how some P waves are conducted through the atrioventricular node with a resulting QRS complex, and other P waves are not conducted.

(From Aehlert B: ECGs made easy, ed 3, St Louis, 2006, Mosby.)

Figure 11-31 Two examples of third-degree (complete) heart block. Both show P waves that have no relation with the QRS complexes. The top example has QRS complexes of the normal width, indicating that the atrioventricular (AV) junction is acting as the pacemaker. The bottom example has QRS complexes that are wider than normal because the ventricles are being paced from below the AV junction. Instead, an idioventricular pacemaker is determining the patient’s heart rate.

(From Goldberger AL: Clinical electrocardiography: a simplified approach, ed 7, St Louis, 2006, Mosby.)

Figure 11-32 Two electrocardiogram tracings of junctional premature beats. They are from the same patient but from different leads. Arrows, Retrograde P waves of opposite polarity from normal.

(From Goldberger AL, Goldberger E: Clinical electrocardiography, St Louis, 1981, Mosby.)

Figure 11-33 An electrocardiogram tracing showing ST segment depression. This is usually caused by myocardial hypoxia and can lead to a myocardial infarction if not promptly treated.

(From Wilkins RL, Dexter JR, Heuer AJ: Clinical assessment in respiratory care, ed 6, St Louis, 2010, Mosby.)

Often, however, the patient comes to the hospital too late, and an MI with heart damage is present. If the damaged area is large enough, the heart fails to pump adequately, and the patient dies. A smaller infarct weakens the heart. In addition, the damaged or dying tissue acts as an abnormal focus for the arrhythmias discussed next. The ECG changes that occur during the acute stage of an MI and as the heart heals are shown in Figure 11-34 and are listed here:

• The initial ECG may be normal. This happens about 15% of the time. The patient should be admitted for observation and cardiac enzyme studies if symptoms are present.

• The first sign of an MI is an elevated ST segment. This occurs within a few hours of the injury.

• Next the T wave inverts. This happens within hours to days of the infarct.

• The ST segment returns to the normal baseline position within days to weeks.

• After a period of weeks to months, the T wave becomes upright again. A lasting ECG change is an enlarged Q wave as shown.

a. Premature ventricular contraction. A premature ventricular contraction (PVC) is an abnormal, fast contraction of the ventricles that originates from a focus below the AV node (Figure 11-35). This is usually a sign of a diseased or hypoxic ventricle. Pathologic causes include arteriosclerotic heart disease or MI. An example of an isolated PVC is shown in Figure 11-36 and has these traits:

• It is premature and happens before the normal heartbeat.

• No P wave is present.

• The QRS complex is bizarre looking and more than 0.12 seconds wide.

• The T wave is inverted.

• Usually, a fully compensatory pause occurs before the next normal heartbeat.

Figure 11-34 The sequence of electrocardiogram rhythms commonly seen after a myocardial infarction. See the text for a description of each step in the sequence.

Figure 11-35 Premature ventricular contraction (PVC; arrow) is detected when an impulse is propagated from a ventricular focus before the next normal beat is due. The QRS complex is commonly widened and not preceded by a P wave. A longer than usual (compensatory) pause follows. Retrograde activation of the atria may occur after a premature contraction, or the normal sinus P waves may continue. The sinus P waves after the PVC are blocked by conduction-system refractoriness.

(From Conover MB: Understanding electrocardiography, ed 8, St Louis, 2003, Mosby.)

Figure 11-36 Premature ventricular contractions (PVCs) cause a fully compensatory pause. Note that the interval between the two sinus beats that surround the PVC (R₃ and R₄ in this case) is exactly two times the normal interval between the sinus beats R₁ and R₂. Notice that the P waves come on time, except that the third P wave is interrupted by the PVC and therefore does not conduct normally through the atrioventricular junction. The next (fourth) P wave also comes on time. The fact that the sinus node continues to pace despite the PVC results in the fully compensatory pause.

(From Goldberger AL: Clinical electrocardiography: a simplified approach, ed 7, St Louis, 2006, Mosby.)

A single PVC is not dangerous unless it originates during the T wave, when the heart is especially vulnerable to electrical stimulation (Figure 11-37). Then, it can cause ventricular fibrillation.

Figure 11-37 An electrocardiogram tracing showing multifocal premature ventricular contractions (PVCs). Counting from the left, after the normal beat, note that the next beat and sixth beat are PVCs. Because they look different, they do not originate at the same abnormal focus. Therefore the patient has multifocal PVCs. This dangerous situation should be quickly corrected.

(From Wilkins RL, Dexter JR, Heuer AJ: Clinical assessment in respiratory care, ed 6, St Louis, 2010, Mosby.)

If all PVCs look the same, they originate from the same area (focus) and are called unifocal. All patients with PVCs should be watched more closely and probably treated when their PVCs are seen more frequently than 1 in 10 beats, seen in groups of two or three, or seen in multiple configurations. For example, two different-looking PVCs mean that two different ventricular foci are firing prematurely (Figure 11-38). These different looking PVCs would be called multifocal. Bigeminy occurs when every second beat is a PVC; trigeminy is when every third beat is a PVC. These dangerous situations must be rapidly treated. Lidocaine (Xylocaine) is given intravenously if the heart rate is more than 60 beats/min. If that does not work, procainamide hydrochloride (Pronestyl) is added. Additionally, the patient is given supplemental oxygen to improve oxygenation to the irritable heart.

b. Ventricular tachycardia. Ventricular tachycardia (VT or V tach) is a serious consequence of untreated premature ventricular contractions. VT is defined as a series of three or more consecutive PVCs. Runs of VT may be fairly short or prolonged. The rate counted during VT is between 110 and 250 beats/min. Cardiac output decreases dramatically during this arrhythmia. If the patient has a stable blood pressure, VT is treated with lidocaine as an antiarrhythmic. Synchronized cardioversion is needed if the lidocaine is ineffective. If the VT is sustained and the patient is unresponsive, pulseless, hypotensive, or, in pulmonary edema, defibrillation (also called unsynchronous cardioversion) is necessary. The medication amiodarone HCl (Pacerone) may also be used to help stop ventricular tachycardia. If left untreated, VT usually progresses to either ventricular flutter (Figure 11-39) or ventricular fibrillation (discussed next). Ventricular flutter looks similar on the ECG to VT except that the rate is usually faster and the rhythm less regular. Its treatment is the same as that for VT and, if left untreated, it will progress to ventricular fibrillation. Both of these arrhythmias originate from a single fast ventricular focus, as shown in Figure 11-35.

c. Ventricular fibrillation. Ventricular fibrillation (VF or V fib) is caused when multiple, fast ventricular foci are firing (see Figure 11-40 for the electrical pathways). When several ventricular foci are firing in an uncoordinated manner, the rhythm is chaotic and without any pattern. Virtually no cardiac output occurs. The patient is pulseless and without any blood pressure. This is a true medical emergency. If it is not treated immediately, brain death will occur within minutes. CPR must be started to provide oxygen to the brain. The treatment of choice for VF is defibrillation as quickly as possible. No attempt is made to synchronize the electrical shock. Figure 11-41 shows the usual position of the defibrillator paddles. It is hoped that with prompt CPR efforts and electrical defibrillation, the patient’s heartbeat will return to a normal sinus rhythm (see Figure 11-5).

d. Ventricular asystole. Ventricular asystole (or asystole) occurs when no cardiac electrical signal and no myocardial activity are present. The ECG tracing shows a flat line, indicating the absence of cardiac electrical activity. The presence of this arrhythmia is ominous. When seen after a full attempt at CPR, it indicates a nonfunctioning heart. The patient will almost assuredly die. Some physicians may elect to defibrillate the patient in asystole in an attempt to generate some sort of rhythm. Because of the dire consequences of ventricular asystole, it is wise to double-check all the equipment. This includes the ECG leads or defibrillator paddles being used to check the rhythm, all electrical connections, and the functioning of the ECG monitor to be sure that no technical error can be found.

Figure 11-38 Electrocardiogram tracing showing normal sinus rhythm that suddenly converts to ventricular tachycardia. This can happen if a premature ventricular contraction occurs early in the heart’s repolarization process and is called the R-on-T phenomenon. If ventricular tachycardia is not treated promptly, it will deteriorate into ventricular flutter or ventricular fibrillation.

(From Wilkins RL, Dexter JR, Heuer AJ: Clinical assessment in respiratory care, ed 6, St Louis, 2010, Mosby.)

Figure 11-39 Example of an electrocardiogram showing ventricular flutter. If this arrhythmia is not treated promptly, it will deteriorate into ventricular fibrillation.

(From Kacmarek RM, Mack CW, Dimas S: The essentials of respiratory care, ed 3, St Louis, 1990, Mosby.)

Figure 11-40 Multiple disorganized contractions of the ventricles characterize ventricular fibrillation and represent cardiac arrest. It may be of sudden onset or may follow premature ventricular contractions, ventricular tachycardia, or ventricular flutter.

(From Stein E: Clinical electrocardiography: a self-study course, Philadelphia, 1987, Lea & Febiger.)

Figure 11-41 Schematic drawing of automated external defibrillator and its attachment to the patient.

(Modified from Cummins RO: Advanced cardiac life support, Dallas, Tex., 1994, American Heart Association.)

b. Draw an arterial blood gas sample (Code: IB9f, IIIE2a) [Difficulty: ELE: R, Ap; WRE: An]

Blood for arterial blood gas (ABG) determination is usually drawn in any hospital-based CPR effort. It should not be done at the expense of time that should be spent starting effective ventilations and chest compressions or defibrillating the heart. The blood gas values give important information on the patient’s oxygenation and helps to determine whether the patient is acidotic. Changes in the ventilation efforts and medications such as bicarbonate are based on information from the ABGs. See Chapter 3 for the discussion on arterial blood sampling.

The femoral site is usually the best to draw from in a CPR situation because it is the largest artery and the easiest to hit. It is far enough from the chest that blood can be drawn without interfering in the chest compression efforts.

c. Interpret the results of arterial blood gas analysis (ELE code: IIIE4a) [Difficulty: ELE: R, Ap, An]

The full discussion of ABG interpretation is presented in Chapter 3. During a CPR attempt, the key things to look for are the patient’s Pao₂ and PaCO₂, because they relate to the adequacy of ventilations and chest compressions. If the patient has an acidotic pH and a normal or low PaCO₂, the patient has an uncorrected metabolic acidosis. Intravenous (IV) sodium bicarbonate is indicated.

d. Perform endotracheal intubation (Code: IIIB3) [Difficulty: ELE: R, Ap; WRE: An]

Oral endotracheal intubation is usually performed during a CPR attempt. See Chapter 12 for a complete discussion of endotracheal tubes, intubation equipment, and the process of performing intubation. Current CPR guidelines indicate that if an endotracheal tube cannot be placed into a patient, a laryngeal mask airway (LMA) or Combitube may be inserted to provide a secure airway.

e. Make the recommendation to defibrillate the patient

Defibrillation sends a specific amount of direct electrical current (DC) through the patient’s chest wall and heart. Its purpose is to stimulate the entire cardiac muscle and electrical system so that the source of an abnormal signal will be suppressed. The SA node usually then takes over as the normal pacemaker. Chapter 18 includes a table listing the stepped progression of power used in defibrillation.

Synchronized defibrillation (cardioversion) (see Chapter 18) should be performed under the following circumstances: atrial flutter, PAT, atrial fibrillation, and ventricular tachycardia unless the patient is pulseless, unresponsive, hypotensive, or in pulmonary edema.

Unsynchronized defibrillation should be performed as soon as possible under the following circumstances: ventricular fibrillation or ventricular tachycardia when the patient is pulseless, unresponsive, hypotensive, or in pulmonary edema.

f. Recommend ACLS protocol agents (Code: IIIG4d) [Difficulty: ELE: R, Ap; WRE: An]

g. Administer ACLS protocol medications by endotracheal installation (Code: IIID5c) [Difficulty: ELE: R, Ap; WRE: An]

Cardiac medications may be instilled down the endotracheal tube when a resuscitation attempt is under way and the patient does not have a functional central or peripheral IV line. The following medications may be instilled into adult patients: naloxone (Narcan), atropine, vasopressin (Arginine), epinephrine, and lidocaine (Xylocaine). (Hint: Use “NAVEL,” from the first letters of the generic name of these medications, to help remember them.) Naloxone should only be given intravenously to a newborn infant. The dose of any medication is based on the patient’s size and may be larger than that given intravenously. This is because the medication is diluted through the airways and must be absorbed through the mucous membrane. Previous adult guidelines indicated that the endotracheal dose should be 2 to 2.5 times greater than the normal IV amount. The medication should be diluted by adding 10 mL of normal saline or distilled water. ‘

The following steps for instillation are recommended:

h. Observe the size of the patient’s pupils and their reaction to light

Normally the pupils constrict when a light being shined into them. The pupils dilate within 30 to 40 seconds after cardiac arrest and do not constrict normally when the brain is hypoxic. If CPR is being done properly to deliver oxygen to the brain, the pupils should constrict normally. Fixed (nonreactive) and dilated pupils are ominous signs. Even if the heart can be restarted, the brain has probably had irreversible damage.

In several conditions, the pupils do not react as expected. The pupils remain constricted if the victim has received morphine sulfate or other opiates. The pupils are dilated if the victim has received atropine, quinidine, or epinephrine. Hypothermia also causes the pupils to dilate.

i. Recommend (Code: IC10) [Difficulty: ELE: R, Ap; WRE: An] and perform capnography or exhaled carbon dioxide measurement (Code: IB9c) [Difficulty: ELE: R; WRE: Ap, An] to evaluate the adequacy of resuscitation

The general discussion of capnography was presented in Chapter 5, and exhaled carbon dioxide monitoring was presented in Chapter 12. Either can be used to help confirm that the endotracheal tube is properly located within the trachea and the patient is exhaling carbon dioxide. It also is helpful if the patient is being transported or the endotracheal tube is being repositioned. In addition, clinical evidence suggests that monitoring the exhaled carbon dioxide level during a CPR attempt is helpful in evaluating the patient’s metabolic response. In general, if chest compressions and assisted ventilation are effective, carbon dioxide will be removed from the tissues and circulated to the lungs for exhalation. If the CPR efforts are ineffective, little exhaled carbon dioxide is measured. The absence of exhaled carbon dioxide, despite a proper CPR effort, is a grave sign.

a. Terminate the treatment or procedure based on the patient response (Code: IIIF1) [Difficulty: ELE: R, Ap; WRE: An]

The practitioner should make a recommendation to the physician to stop a procedure being performed as an adjunct to CPR if the patient is having an adverse reaction to it. For example, bag and mask ventilation may force air into the stomach; recommend intubation. Always notify the physician of any change in the patient’s condition or if a complication to any CPR-related procedure is seen.

b. Recommend discontinuing treatment based on the patient’s response (Code: IIIG1i) [Difficulty: ELE: R, Ap; WRE: An]

The physician will make the decision to stop futile CPR activities that are taking place in the hospital.