Ch39 Responding to the Field Code.docx

Chapter 39 Responding to the Field Code Unit Summary Upon completion of the chapter and associated learning materials the student will be able to integrate comprehensive knowlegde of causes and pathophysiology into the management of cardiac arrest and prearrest states. Students will be able to explain the importance of the American Heart Association’s five links of survival to a successful code. Students will be able to describe the management acronym SMART and each of its objectives. Students will be able to discuss how progressive communities can improve survival of prehospital cardiac arrest patients. Students will be able to discuss how the use of simulation in training can improve the resuscitation skills of healthcare providers. Students will be able to discuss the revisions made by the American Heart Association and International Liason Committee on Resuscitation to the Emergency Cardiovascular Care and CPR guidelines. Students will be able to summarize the steps of the BLS healthcare algorithm including the proper techniques for performing two-rescuer CPR in adults, children, and infants. Students will be able to discuss when an automated external defibrillator (AED) should be used for an adult, child, or infant. Students will be able to summarize the correct sequence for the use of an AED. Students will be able to identify special situations related to the use of an AED. Students will be able to describe the management of a cardiac arrest based on the analysis of the ECG as either a shockable or nonshockable rhythm. Students will be able to list the “Hs and Ts” and explain how they can be managed in the field. Students will be able to describe the different mechanical devices that are available to assist in delivering improved circulatory efforts during CPR. Students will be able to discuss the ethical issues related to the initiation and cessation of resuscitative efforts. Finally, students will be able to explain the importance of the team concept during a code and the various roles of each team member. National EMS Education Standard Competencies Shock and Resuscitation Integrates comprehensive knowledge of causes and pathophysiology into the management of cardiac arrest and pre-arrest states. Knowledge Objectives Discuss the importance of the American Heart Association’s five links of the Chain of Survival to a successful code. (pp 1851–1852) Describe the management acronym SMART and each of its objectives. (p 1852) Describe how progressive communities can improve survival of prehospital cardiac arrest patients. (p 1852) Discuss the use of simulation in CPR training. (pp 1852–1853) Discuss some of the revisions made by the American Heart Association (AHA) and International Liaison Committee on Resuscitation (ILCOR) to the Emergency Cardiovascular Care (ECC) and CPR guidelines. (pp 1853–1854) Describe how you, your crew, and your agency can incorporate the latest guidelines into the management of field codes. (pp 1852–1854) Discuss some of the theories that have shifted the focus of certain CPR techniques. (p 1854) Summarize the steps of the BLS healthcare provider algorithm and identify the key to a successful outcome in patients with cardiac arrest. (pp 1854–1855) Explain how two-rescuer CPR can benefit the paramedic and the patient. (p 1856) Explain the steps in providing two-rescuer adult CPR, including the method for switching positions during the process. (p 1856) Identify the various age groups of infants and children for the purposes of resuscitation procedures and equipment. (p 1856) Explain the steps in providing child and infant CPR, including the method for switching positions during the process. (pp 1858–1860) Discuss guidelines for circumstances that require the use of an automated external defibrillator (AED) on both adult and pediatric patients experiencing cardiac arrest. (pp 1861–1862) Describe situations in which manual or automated defibrillation would be appropriate. (p 1862) Summarize how to perform manual defibrillation on an adult and child/infant. (p 1862) Summarize how to use an automated external defibrillator. (pp 1864–1865) Describe how to manage a witnessed arrest versus a nonwitnessed arrest. (p 1865) Explain special situations related to the use of automated external defibrillation. (pp 1865–1866) Review the management of a cardiac arrest based on analysis of the electrocardiogram (ECG) as either a shockable (ventricular fibrillation or ventricular tachycardia) or a nonshockable (pulseless electrical activity or asystole) rhythm. (pp 1866, 1868) List the “Hs and Ts” and how they can be managed in the field. (p 1869) Describe the different mechanical devices that are available to assist in delivering improved circulatory efforts during CPR. (pp 1870–1872) Describe the general steps of postresuscitative care. (p 1872) Describe the ethical issues related to patient resuscitation, providing examples of when not to start CPR on a patient. (pp 1872–1873) Explain the various factors involved in the decision to stop CPR once it has been started on a patient. (p 1873) Discuss the value of scene choreography at a field code. (pp 1873–1874) Describe the typical roles of the code team leader and code team members at a field code. (p 1874) Plan for a code by reviewing a sample script for a typical prehospital cardiac arrest resuscitation. (p 1875) Skills Objectives Demonstrate how to perform one- and two-rescuer adult CPR. (p 1857 , Skill Drill 1) Demonstrate how to perform CPR in a child who is between age 1 year and the onset of puberty. (p 1859 , Skill Drill 2) Demonstrate how to perform CPR in an infant who is between ages 1 month and 1 year. (p 1860 , Skill Drill 3) Demonstrate how to perform manual defibrillation in an adult patient. (p 1863 , Skill Drill 4) Demonstrate how to perform manual defibrillation in an infant or child. (pp 1863–1864) Demonstrate how to manage a patient in ventricular fibrillation or ventricular tachycardia. (pp 1864–1865, 1868–1869) Demonstrate how to manage a patient in asystole or pulseless electrical activity. (pp 1869–1870) Demonstrate the steps of postresuscitative care. (p 1872) Demonstrate how to be committed to the success of the team. (pp 1873–1874) Demonstrate the roles of the code team member and the code team leader. (p 1874) Readings and Preparation • Review all instructional materials including Chapter 39 of Nancy Caroline’s Emergency Care in the Streets, Seventh Edition, and all related presentation support materials. • Consider reading the following article ahead of time and summarizing the material for students or including it during classroom discussion. 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care http://circ.ahajournals.org/content/122/18_suppl_3/S639.full.pdf+html Support Materials • Lecture PowerPoint presentation • Case Study PowerPoint presentation Enhancements • Direct students to visit the companion website to Nancy Caroline’s Emergency Care in the Streets, Seventh Edition, at http://www.paramedic.emszone.com for online activities. Invite a local cardiologist to give a presentation on the various aspects of sudden cardiac arrest and how EMS can help increase survival rates. Content connections: The chapter on Cardiovascular Emergencies, and all related presentation support materials, provide a detailed review of cardiac dysrhythmias and appropriate management. Cultural considerations: Not all cultures respond to the death of a family member in the same manner. Students may encounter a wide variety of emotional responses and expression. Take the time to research various cultural responses to death and dying and share the information with the students. Teaching Tips If possible, have a cardiac arrest survivor speak to the class about their experience. Another option would be to extend an invitation to family members of people who experienced an out-of-hopsital cardiac arrest to share their perspective about cardiac arrest and resuscitation. Ask them to provide feedback on how EMS providers could have improved their experience. Unit Activities Writing activities: Assign the students a research paper on the historical perspectives of CPR. Student presentations: Have the students present their findings from their research. Group activities: Invite the students to participate in a BLS instructor course. Visual thinking: Provide the students with examples of several ECGs and have them write out the approriate treatment algorithm. Pre-Lecture You are the Medic “You are the Medic” is a progressive case study that encourages critical-thinking skills. Instructor Directions Direct students to read the “You are the Medic” scenario found throughout Chapter 39. • You may wish to assign students to a partner or a group. Direct them to review the discussion questions at the end of the scenario and prepare a response to each question. Facilitate a class dialogue centered on the discussion questions and the Patient Care Report. • You may also use this as an individual activity and ask students to turn in their comments on a separate piece of paper. Lecture I. Introduction A. In the early 1970s, few people survived a prehospital sudden cardiac arrest. 1. CPR training programs in the mid 1970s began to improve outcomes. a. Today EMS crews expect the return of spontaneous circulation (ROSC) during the resuscitation of a patient in cardiac arrest. 2. EMS systems have trained the public in CPR and placed automated external defibrillators (AEDs) in public places, leading to tremendous success in ROSC. a. The ROSC rate in some communities is as high as 40%. b. Careful implementation of the Emergency Cardiovascular Care (ECC) guidelines improves outcomes. 3. The American Heart Association (AHA) and the International Liaison Committee on Resuscitation (ILCOR) revise the guidelines for ECC and CPR every 5 years. II. Improving the Response to Cardiac Arrest A. Chain of Survival 1. After recognition of a cardiac emergency, the following five links in the Chain of Survival are needed: a. Early access to 9-1-1 b. Early high-quality CPR by the public or responders c. Early defibrillation d. Early advanced life support care e. State-of-the-art postresuscitative care at a hospital 2. A team of skilled providers is required, including: a. CPR-trained community members b. First responders with an AED c. EMTs and paramedics who have been well trained in high-quality CPR 3. The prehospital team should practice working together, directed by a code team leader. B. Developing prehospital program objectives: The SMART way 1. Community-based programs to improve the survival of prehospital cardiac arrest patients can benefit from SMART objectives. a. Specific b. Measurable c. Attainable and achievable d. Realistic and relevant e. Timely 2. The following questions can help improve response: a. Is there a universal access number? Does the public know how and when to use it? b. Are all dispatchers/communicators trained to provide hands-only CPR telephone instruction? i. Does their medical director review 100% of the cardiac arrests for response time and compliance with protocols? c. Is a community CPR training program available at little to no cost? i. If so, does the public know? ii. Have 10% to 20% of the population been trained? d. Is learning CPR a high school graduation requirement? i. If not, how can you change this? e. Are 100% of emergency responders trained in CPR and use of the AED? Do all response vehicles have an AED? f. Are AEDs and trained personnel available in all locations of public assembly for 500+ people or in high-risk locations? g. Do all schools have AEDs readily available? Is the AED at all sporting events? h. Are fitness center personnel trained in CPR and AEDs readily available? i. How long does it take for the first emergency responder and paramedics to arrive on the scene? Is this data published regularly? j. Does the EMS medical director review all cardiac arrests and make quality improvements? k. Are cardiac arrests reported using the Recommended Guidelines for Uniform Reporting of Data from Out-of-Hospital Cardiac Arrest, “The Utstein Style”? l. Do all hospitals you transport to participate in the AHA’s Get With The Guidelines quality improvement suite? m. Do prehospital and in-hospital code teams practice regularly with simulated patients? i. Drills should focus on teamwork, following guidelines, and ensuring minimal interruptions in CPR. C. Simulation training, or “mock code” training 1. Simulation modules can help train you for low-frequency, high-risk situations such as lethal dysrhythmias and cardiac arrest. a. These simulations use “high-fidelity” manikins and videotaping to mock the code for review and analysis. i. Actions and results are tracked for critique and review. b. High-fidelity manikins combine with a computer simulator to play out preprogrammed scenarios involving alterations in: i. Vital signs ii. Electrocardiogram (ECG) iii. SpO2 iv. End-tidal carbon dioxide (ETCO2) v. Other parameters D. Development of new CPR guidelines 1. Reemphasis on quality CPR a. During the 1990s CPR quality seemed to slip as providers focused on intubation, drugs, defibrillation, and other aspects of field code management. i. Depth of compressions was inadequate. ii. Rate of compressions was too slow. iii. Almost half the time no compressions were provided. iv. Ventilations were too fast. v. Chest was rarely allowed to fully recoil. b. CPR is important both before and immediately after defibrillation. i. Immediate CPR can double or triple the survival rate with ventricular fibrillation (V-fib) or sudden cardiac arrest. c. CPR guidelines emphasize the importance of high-quality CPR beginning with compressions. i. Base of “resuscitation pyramid” is high-quality compressions (fast, deep, full recoil). ii. Success does not rely on an IV, ET tube, circulatory adjunct, or drugs. iii. Continuous, uninterrupted, high-quality CPR compressions are your best chance of success. 2. Airway management a. There is a reduced emphasis today on “securing” the airway with endotracheal intubation (the “gold standard”). i. Research shows that high-quality compressions can double or triple the chance of survival if administered promptly. ii. Focus on interventions that make a measurable difference in survival (ie, defibrillation). iii. ET tube insertion is not a priority if the airway can be opened and ventilation is successful using basic adjuncts. b. Consider advanced airways if a basic airway is not adequate or the airway needs better protection (eg, vomiting). i. Place advanced airways with minimum interruption in compressions (less than 10 seconds). ii. If this cannot be accomplished, a rescue airway may be used. c. Control of ventilation volume and rate is important with airway maintenance and adjunct placement. i. Ventilations should be 1 second in duration each. ii. Volume should be just enough to see visible chest rise. iii. Do not overventilate. (a) Can cause gastric distention or regurgitation. (b) Excessive gas in the chest significantly reduces coronary artery perfusion. d. Some medical directors have encouraged paramedics to use an impedance threshold device (ResQPOD). i. Placed in the ventilation circuit between the mask and the bag-mask device or automated transport ventilator (ATV) ii. Enhances compressions by creating a vacuum in the chest that allows more blood to flow to the heart and brain iii. Prompt helps keep track of the ventilation rate so as to not exceed the recommended rate. (a) 2 ventilations every 30 compressions, or (b) 1 ventilation every 6 to 8 seconds when an advanced airway is inserted e. If the Chain of Survival is “in place,” there is about a 40% chance of ROSC. i. If the patient wakes up, it is best to not have an ET tube in place. ii. If the patient does not wake up and is a candidate for postarrest hypothermia therapy, you may need to intubate and provide medication to prevent shivering. iii. The decision to place an advanced airway should be based on the patient’s situation, not performed automatically. 3. Blood flow during CPR a. Theories on blood flow during CPR have evolved. b. Heart pump theory: The heart is directly squeezed by compression between the sternum and the spinal column. i. Blood flows from higher pressured chambers to the lowered pressured vessels and organs. ii. Heart valves need to function properly to keep the blood flowing in the right direction and prevent retrograde blood flow. c. Thoracic pump theory: Compression of the sternum raises pressure in the chest cavity. i. Venous collapse prevents backflow of blood; open arteries allow for forward blood flow out of the chest. ii. Administration of epinephrine and other vasopressors can help keep those essential arteries open. d. Harder and faster compressions increase pressure to a greater degree. i. Interruptions in compressions cause blood movement to cease. ii. The current emphasis is on continuous chest compressions with minimum, if any, interruptions. e. Current theories consider the importance of negative intrathoracic pressure. i. Patients in cardiac arrest are not breathing on their own, so they do not produce negative inspiratory pressure to assist in blood flow. ii. During CPR, some negative pressure develops as the sternum and ribs rebound to their normal position during decompression. iii. Thus the 2005 guidelines emphasize “full chest recoil.” iv. Greater negative pressure in the chest (push hard and fast, allow full chest recoil) causes a greater amount of blood to be returned to the heart. (a) Then on the next compression more blood is forced to the heart’s coronary arteries and vital organs. (b) An impedance threshold device or ResQPOD can enhance this negative pressure gradient. III. Adult CPR A. Initial steps for managing an adult in cardiac arrest follow the adult BLS healthcare provider algorithm. 1. The key to a successful outcome is how quickly compressions are initiated. a. Establish unresponsiveness and lack of “normal” breathing. b. Spend no more than 10 seconds determining pulselessness. c. If there is no pulse, begin CPR and continue for 2 minutes or five cycles of 30 compressions and 2 ventilations. d. Always bring your AED or defibrillator/monitor on any potential cardiac arrest call. e. In all patients, begin CPR and attach the AED as soon as it is available. 2. The public is generally not taught to take a pulse or perform rescue breathing or two-person CPR. 3. Bystanders are often reluctant to begin CPR for the following reasons: a. CPR steps may have been too complicated and hard to remember. i. The new guidelines emphasize simpler, hands-only CPR with the focus on compressions. b. Training methods may have been inadequate, and skill retention typically declines rapidly after a course. i. A video-based watch-and-do method has been incorporated into most courses. c. Some people are afraid of transmitted diseases and are reluctant to perform mouth-to-mouth resuscitation. i. Barrier devices and hands-only/compression-only CPR is encouraged in such cases. d. Many bystanders who were trained but did not help with a cardiac arrest stated that they were afraid of doing the wrong thing. B. Two or more rescuer CPR 1. Two-rescuer CPR is less tiring and facilitates effective chest compressions. a. A team approach to CPR and AED use is far superior to the one-rescuer approach. b. Once one-rescuer CPR is in progress, additional rescuers can easily be added. c. Prior to assisting with CPR, a second rescuer should: i. Apply the AED. ii. Set up airway adjuncts including a bag-mask device and suction. iii. Insert an oral airway. d. If CPR is in progress, the second rescuer should enter the procedure after a cycle of 30 compressions and two ventilations. 2. Rotate the compressor every 2 minutes. a. A third rescuer should kneel on the other side of the patient’s chest from the rescuer performing compressions. b. The “on-deck compressor” can take over after five cycles or 2-minute intervals. c. Studies show that the compressor tires after 2 to 5 minutes. i. Quality will suffer if the compressor is not replaced. 3. To properly perform two-rescuer adult CPR, refer to Skill Drill 39-1. 4. Once an advanced airway has been inserted, compressions and ventilations are no longer in cycles. a. They are asynchronous with the compressor providing at least 100 per minute without pauses for breaths and the ventilator giving 8 to 10 breaths/min (every 6 to 8 seconds). b. Switch compressors every 2 minutes with no more than 10-second pauses, if any. IV. CPR for Infants and Children A. The guidelines use definitions of age groups for the purposes of resuscitation. 1. Newly born—an infant within the first few hours after birth 2. Neonate—an infant within the first month after birth 3. Infant—1 month to 1 year 4. Child—age 1 year to adolescence (signs of puberty) 5. Adult—adolescent and older B. In most cases, cardiac arrest in infants and children follows respiratory arrest, which triggers hypoxia and ischemia of the heart. 1. Children consume oxygen two to three times as rapidly as adults. a. You must open the airway and provide artificial ventilation. i. Often this will allow the child to resume spontaneous breathing and prevent cardiac arrest. ii. Airway and breathing are a focus of pediatric BLS. 2. Respiratory problems in children can have a number of different causes, including the following: a. Injury, both blunt and penetrating b. Infections of the respiratory tract or another organ system c. Foreign body in the airway d. Submersion e. Electrocution f. Poisoning or drug overdose g. Sudden infant death syndrome 3. Pediatric BLS can be divided into four steps: a. Determine responsiveness b. Circulation c. Airway d. Breathing C. Technique for children 1. CPR technique has a few slight variations for children. a. To properly perform CPR on a child, refer to Skill Drill 39-2. 2. Switching rescuer positions is the same for children as for adults—every 2 minutes of CPR. a. If the child is past the onset of puberty, use the adult CPR sequence, including the use of the AED. 3. Once an advanced airway has been inserted, compressions and ventilations are no longer in cycles. a. They are asynchronous with the compressor providing at least 100 per minute without pauses for breaths and the ventilator giving 8 to 10 breaths/min (every 6 to 8 seconds). b. Switch compressors every 2 minutes with no more than 10-second pauses, if any. D. Technique for infants 1. CPR technique for an infant varies slightly. a. To properly perform CPR on an infant, refer to Skill Drill 39-3. 2. With two rescuers, compressions can also be performed using the two thumb-encircling-hands technique. a. If the chest does not rise, or rises only a little, open the airway with a head-tilt chin-lift. b. Reassess for signs of spontaneous breathing after five cycles of CPR. V. Defibrillation A. When an unresponsive patient is receiving CPR, the AED is one of the first pieces of equipment you will obtain from the ambulance. 1. Defibrillation delivers a surge of electric energy to the heart. 2. A paramedic is likely to administer electricity in one of three ways: a. Defibrillation b. Cardioversion c. Transcutaneous pacing (TCP) 3. Defibrillation is appropriate when a cardiac arrest patient is in V-fib or pulseless V-tach. 4. Cardioversion and TCP are reserved for patients who are not yet in cardiac arrest. 5. If you are the first responder, you are likely to use an AED as opposed to a manual defibrillator. a. Many communities have placed AEDs in public places. b. Adhere to the following guidelines: i. Adults: Use a standard adult AED unit. ii. Children (age 1 year to the onset of puberty): Use an AED with pediatric dose-attenuation if available. (a) If unavailable, use a standard adult AED. iii. Infants (ages 1 month to 1 year): A manual defibrillator should be used if available. (a) Otherwise use a pediatric dose-attenuator. (b) If neither is available, use a standard adult AED with the pads in the A/P position. iv. Newborns (birth to age 1 month): Focus on CPR with emphasis on ventilation. 6. Carry out defibrillation as soon as possible in two rhythms—V-fib and pulseless V-tach. a. If you witness the arrest, begin CPR with chest compressions and attach the AED as soon as it is available. b. If the arrest was not witnessed, perform five cycles of CPR before applying the AED. i. The heart is more likely to respond to defibrillation within the first few minutes of ventricular fibrillation. ii. If the arrest interval is prolonged: (a) Metabolic waste products accumulate in the heart. (b) Energy stores are rapidly depleted. (c) The chance of successful defibrillation is reduced. iii. A 2-minute period of CPR before AED use with prolonged arrest (greater than 4 to 5 minutes) can: (a) Restore oxygen to the heart. (b) Remove metabolic waste products. (c) Increase the chance of successful defibrillation. c. If the cardiac arrest is not witnessed and CPR is not in progress, immediately start CPR and continue for 2 minutes before delivering the first shock. i. If the rhythm converts to V-fib or pulseless V-tach and the defibrillator is already attached, perform CPR only long enough to charge the defibrillator and then defibrillate. ii. Defibrillation is not useful in asystole. (a) No evidence that the myocardial cells are spontaneously depolarizing. (b) Defibrillation of asystole is harmful due to the unnecessary interruption of compressions. (c) If you are unsure about asystole after checking more than one lead, resume CPR and follow the asystole pathway in the pulseless arrest algorithm. B. Manual defibrillation 1. Some defibrillators can perform manual or automated defibrillation. 2. In manual defibrillation, you interpret the cardiac rhythm and determine if defibrillation is needed. a. Manual units require you to select the appropriate dose. i. A default setting of 200 J is usually used. ii. Settings may range from 120 J to 200 J, depending on the manufacturer. b. After you deliver a shock, immediately begin chest compressions for a 2-minute cycle, then reassess for pulse return and rhythm change. i. If your unit has both manual and AED mode, it is faster to use the manual mode. (a) You can interpret the rhythm more quickly than the AED. 3. To properly perform manual defibrillation in an adult, refer to Skill Drill 39-4. 4. To perform manual defibrillation in an infant or child: a. Confirm unresponsiveness, pulselessness, and apnea. b. Begin CPR if a defibrillator is not immediately available. c. Use defibrillation pads for hands-free system or select the proper paddle size. i. If using paddles, apply conductive gel. d. Place one pad on the anterior chest wall to the right of the sternum, inferior to the clavicle; place the other pad on the left midclavicular line at the level of the xiphoid process. i. Apply firm pressure. e. For children younger than 1 year or who weigh less than 22 lb, you may use anterior-posterior placement. f. Assess the cardiac rhythm to confirm V-fib or pulseless V-tach. g. Select the appropriate energy setting, and charge the defibrillator. h. Ensure that no one is in contact with the patient. i. Deliver the shock at the appropriate setting. j. Give five cycles of CPR. k. Reassess the rhythm. l. If a shockable rhythm persists, give an additional shock at an increased or the same energy. i. Immediately resume CPR. m. Establish IV/IO access and begin medication therapy. i. Consider an advanced airway. ii. Repeat defibrillation after five cycles of CPR if refractory V-fib or pulseless V-tach persists. 5. Most EMS systems use pregelled defibrillator pads instead of paddles. a. Place pads in the same location as you would when using an AED. b. Ensure that there are no air pockets in the pad-skin interface. i. They may result in skin burns and decreased effectiveness. 6. The initial energy setting for defibrillation of pediatric patients is 2 J/kg. a. If this level is not successful, repeat at 4 J/kg. b. Further defibrillation should occur at 4 J/kg after cycles of CPR, as needed. 7. With ongoing CPR, search for and treat any underlying reversible causes (Hs and Ts). 8. Give epinephrine only after two shocks, doubling the dose for the second attempt. 9. Consult with your medical director, medical control physician, or local protocols for transport decisions. 10. Early ROSC (less than 5 min) and V-fib or V-tach as a presenting rhythm are associated with improved neurologic outcome for survivors of pediatric cardiopulmonary arrest. C. Automated external defibrillation 1. Paramedics usually perform manual defibrillation but must know how to use AEDs. 2. An automated external defibrillator (AED): a. Interprets the cardiac rhythm and determines if defibrillation is needed b. Is used by personnel who are not trained in ECG rhythm interpretation c. Can assess the patient’s rhythm and—if V-fib or V-tach is present—charge the pads and prompt the rescuer to deliver a countershock d. Can be preprogrammed so that the user does not have to select a dose e. May be fully automated, though these are now rare 3. A semiautomated AED detects V-fib and rapid V-tach, and a voice prompt may say, “Shock advised. Press to shock.” a. Depress the shock button to defibrillate. 4. Observe safety measures. a. Distance yourself from the patient. b. Do not defibrillate a patient who is in pooled water or is touching metal. c. Remove a nitroglycerin patch and wipe the chest with a dry towel before defibrillation to prevent ignition of the patch. 5. Follow local protocols after AED use. a. One of the following outcomes is likely: i. Pulse is regained. ii. No pulse is regained; AED indicates that no shock is advised. iii. No pulse is regained; AED indicates that a shock is advised. b. For each scenario, the sequence of compressions and defibrillation is the same as manual defibrillation, except the AED determines whether the rhythm is shockable. D. Shockable ECG rhythms 1. The two shockable ECG rhythms are V-fib and pulseless V-tach. a. Shockable rhythm: The heart is quivering but blood is not pumping. b. Defibrillation stuns the heart muscle momentarily and allows the normal conduction system to resume control. c. If the patient is not defibrillated, the V-fib will deteriorate to asystole or flatline. 2. In the first moments of a cardiac arrest, the heart is oxygenated and “ready” to receive a shock. a. Begin CPR, and attach the AED as quickly as possible. b. If a shock is recommended, administer it immediately. c. The chances of a successful defibrillation drop 7% to 10% for every minute that passes. 3. When the V-fib or V-tach is not “fresh,” a rapid shock is not always the best initial treatment. a. When a patient is in cardiac arrest for 4 to 5 minutes or longer, even if the initial ECG showed a shockable rhythm, the success rate is poor. b. Perfusion and oxygenation are needed first. c. Begin CPR, proceed with five cycles or approximately 2 minutes of 30 compressions to two ventilations, and then analyze the ECG. i. If the patient is still in V-fib or V-tach, he or she is ready for a dose of electricity. E. Shock first or compressions first? 1. The decision to deliver a shock first versus provide CPR first is made locally. 2. Many medical directors implement a policy similar to the following: a. If you witness the cardiac arrest, begin CPR with compressions and attach an AED as soon as possible. b. If you do not witness the cardiac arrest, perform five cycles (2 minutes) of CPR prior to applying the AED. c. Deciding whether to count bystander CPR as the first 2 minutes is a judgment call. i. If you observe high-quality compressions, allow the bystander to finish the 2 minutes, unless he or she is tiring, and apply the electrodes around the compressor. 3. The success rate for a biphasic dose is excellent (better than 93%) if the heart is ready to receive the shock. a. If the shock does not work, perform 2 minutes of high-quality CPR. b. Then quickly reanalyze the rhythm and shock as recommended. F. Effective shocks and special circumstances 1. When a shock is effective, occasionally the patient wakes up. 2. The majority of effective defibrillations take a minute or so to bring back circulation. 3. Defibrillation stuns the heart, allowing the pacemaker to begin to beat. a. This may not be enough of a heartbeat to generate a pulse yet. b. After defibrillation, immediately begin compressions. c. The patient may begin to move after a minute or so. 4. After 2 minutes of CPR, take 10 seconds to check for a pulse and review the rhythm. a. If there is ROSC, cease compressions and check for pulse, respirations, and blood pressure. 5. Paddles are rarely used today; defibrillator pads or electrodes are safer. a. ECG is monitored and displayed throughout the arrest, allowing you to observe V-fib or V-tach during compressions and begin to charge up the unit. b. Once the AED is fully charged, the operator should clear all rescuers and deliver the shock. i. Compressions can be delivered while the unit is charging, minimizing the interruption. 6. The code team member who delivers the shock must always first clear the patient! a. Also remove the ventilation device or detach it from the advanced airway to prevent oxygen from flowing across the chest while a shock is being delivered. i. Simultaneous delivery poses a fire hazard. 7. Review these special circumstances for defibrillation. a. Patient is an infant. i. Use the appropriate pediatric pads and an attenuator if available. b. Patient has a hairy chest and the electrodes will not stick. i. Shave the patient just as you would to obtain a 12-lead ECG. c. Patient is submersed in water or soaking wet. i. Move the patient to your ambulance or dry off prior to applying electrodes or providing a shock. d. Patient has an implantable cardioverter defibrillator (AICD) or pacemaker. i. Avoid these devices by a few inches when placing the electrodes. e. Patient has a transdermal medication patch on the chest. i. Remove the patch and wipe the chest dry. ii. Wear disposable gloves to avoid absorbing the nitroglycerin into your skin. VI. The Advanced Cardiac Life Support Algorithm A. The Advanced Cardiac Life Support (ACLS) Algorithm used to manage an adult in cardiac arrest builds on the BLS Healthcare Provider Algorithm. 1. After providing supplementary oxygen, use the monitor or defibrillator to determine whether the patient is still in a shockable rhythm. 2. Two basic pathways for treatment: a. Shockable rhythms (V-fib or V-tach) b. Nonshockable rhythms (asystole or pulseless electrical activity) 3. Medications are drawn up and ready to administer prior to the rhythm checks. a. Medications are administered during CPR without needing to stop compressions. 4. As long as the patient has an effective BLS airway and is adequately ventilated, placement of an advanced airway should never take priority over delivery of high-quality compressions or a shock when needed. a. Practice intubation techniques so you can insert the advanced airway device with no more than a 10-second interruption in chest compressions. B. Managing patients in ventricular fibrillation or ventricular tachycardia 1. Patients with V-fib or pulseless V-tach are the most likely to be resuscitated. a. Continue to perform high-quality CPR, and do a rhythm check at each 2-minute point. i. If the patient is in a shockable rhythm, administer a single shock and immediately begin compressions. b. With three rescuers and an advanced airway, compressions and ventilations can be asynchronous. c. Prepare and administer medications while performing CPR. d. A timekeeper can remind the team leader about upcoming actions. 2. Drug therapy for V-fib or V-tach includes a vasopressor. a. Epinephrine (1:10,000) is given as a 1-mg IV push. i. Repeat this dose every 3 to 5 minutes as long as the pulse is absent. b. Vasopressin is given as 40 units IV push, one time only. i. A single dose may be substituted for the first or second epinephrine dose (but not both). 3. After the third shock, you may decide to administer an antidysrhythmic. a. Amiodarone is given as a 300-mg bolus during CPR. i. May be repeated once at 150 mg in 3 to 5 minutes after the initial dose. b. If amiodarone is unavailable, you may administer lidocaine. i. 1 to 1.5 mg/kg IV push, then 0.5 to 0.75 mg/kg ii. Maximum of 3 doses, or 3 mg/kg c. Do not combine these two antidysrhythmics. 4. If the patient has torsades de pointes, consider administering magnesium. a. Loading dose 1 to 2 g IV or IO 5. Allow drugs to circulate; reanalyze at the next 2-minute point. a. If the patient remains in a shockable rhythm: i. Administer another shock. ii. Consider other treatable causes (Hs and Ts). C. Managing patients in pulseless electrical activity or asystole 1. Pulseless electrical activity (PEA): Organized cardiac rhythm (other than ventricular tachycardia) on the monitor with no detectable pulse a. Continue to provide high-quality CPR. b. Rhythm check at each 2-minute point. c. If the patient is in a nonshockable rhythm, consider the potential cause (Hs and Ts). i. Some issues can be managed in the field; others will require intervention in the emergency department. d. With three rescuers and an advanced airway, compressions and ventilations can be asynchronous. e. Prepare and administer medications while performing CPR. f. A timekeeper can remind the team leader about upcoming actions. 2. Drug therapy for PEA or asystole includes a vasopressor. a. Epinephrine (1:10,000) is given as a 1-mg IV push. i. Repeat this dose every 3 to 5 minutes as long as the pulse is absent. b. Vasopressin is given as 40 units IV push, one time only. i. A single dose may be substituted for the first or second epinephrine dose (but not both). 3. Consider and manage reversible causes (Hs and Ts). a. If the patient changes to V-fib or V-tach, move back to the shockable side of the algorithm. b. Allow drugs to circulate; reanalyze at the next 2-minute point. 4. Paramedics are trained to follow the current algorithms and use good medical judgment. a. High-fidelity simulators provide excellent learning opportunities for low-frequency, high-risk, or high-impact calls. 5. Key points when managing cardiac arrest: a. Perform high-quality CPR beginning with compressions and minimizing interruptions from start to completion of the code. i. Organize the code around 2-minute cycles of 30:2 (compressions to ventilations). ii. Then switch compressors and analyze the rhythm. iii. If an advanced airway is inserted, switch to asynchronous compressions of at least 100 per minute, and ventilate every 6 to 8 seconds (a rate of 8 to 10 per minute). b. If a shockable rhythm is identified, continue compressions until the defibrillator is charged to the appropriate dose. i. Stop, clear, and deliver the shock. ii. Immediately begin compressions unless the patient wakes up. c. Without interrupting CPR, obtain IV/IO access and administer epinephrine every 3 to 5 minutes for the duration of the code (provided the patient is not hypothermic). i. After a cycle of CPR and shock, if necessary, administer an antidysrhythmic drug for V-fib/V-tach. d. For asystole or PEA, do not deliver shocks. e. For all arrests, consider and treat reversible causes. f. If you decide to insert an advanced airway, confirm and monitor with waveform capnography and switch to asynchronous compressions/ventilations. i. Never overventilate; this causes a deadly restriction on coronary perfusion. g. If the patient experiences ROSC, capnography might show a sustained increase in ETCO2. i. Turn to monitoring vital signs. ii. Obtain a 12-lead ECG. iii. Prepare for transport. VII. Mechanical Adjuncts to Circulation A. Several devices can provide immediate feedback on the quality of compressions (rate, depth, and chest recoil). 1. Four devices show promise in improving the quality and consistency of compressions and improving blood flow during CPR: a. Impedance threshold device (ITD) b. Three mechanical compression adjuncts i. AutoPulse ii. Thumper iii. Lucas 2 B. Impedance threshold device (ITD) 1. Marketed as ResQPOD in the United States. 2. Enhances the vacuum in an adult’s chest that forms during the chest recoil phase of CPR. a. When the chest wall reexpands, a vacuum pulls air into the lungs and blood back into the heart. i. An ITD prevents that unnecessary air from rushing into the chest, maximizing the vacuum during the recoil phase of the compression. (a) Results in enhanced return of blood that increases cardiac output, blood pressure, and perfusion to vital organs (b) Use may improve circulation during CPR and increase ROSC. 3. Given a strong recommendation (Class IIa rating) by the AHA in its 2005 guidelines 4. Should be removed from the ventilation system as the patient’s pulse returns i. Use in conjunction with compressions. C. Load-distributing band CPR or vest CPR device 1. The AutoPulse device delivers consistent, uninterrupted adult chest compressions and thus improves hemodynamics during cardiac arrest. a. Automated, portable device b. Easy-to-use, load-distributing LifeBand squeezes the entire chest, thereby improving blood flow to the heart and brain during cardiac arrest. c. Can free up rescuers to focus on other lifesaving interventions and eliminate fatigue. 2. The AutoPulse can be integrated into a code as follows: a. Ensure that CPR with high-quality compressions is in progress. b. Align the patient on the AutoPulse platform. c. Close the LifeBand chest band over the chest. d. Press the start button (AutoPulse performs the compressions automatically). e. Provide bag-mask ventilation at a rate of two ventilations for every 30 compressions. i. Each ventilation should be given over 1 second. f. With an advanced airway, compressions are continuous (at least 100/min), and the ventilation rate is 8 to 10 per minute. g. After 2 minutes of CPR, reassess for pulse and/or shockable rhythm (maximum interruption of 10 seconds). D. Thumper CPR device 1. Adjunct to adult CPR that provides continuous chest compressions (at least 100 per minute) and ventilations. a. Can be used with a pocket mask or an advanced airway. b. Powered by oxygen and delivers oxygen when it ventilates. i. Goes through a large volume of oxygen. ii. Carry additional portable oxygen tanks equipped with high-pressure hose adapters to facilitate rapid transfer of the gas. iii. Use these high-pressure adapters in the ambulance, and have them available for use in the emergency department. 2. The Thumper has been particularly useful in lengthy arrests. a. Can produce excellent CPR compressions for a long time b. Apply as early as possible to avoid interruptions in manual CPR. E. Mechanical piston device 1. Depresses the adult sternum via a compressed gas-powered plunger mounted on a backboard. 2. More recent device is the Lucas 2 mechanical piston device. a. Similar to the Thumper with a piston that compresses the chest b. Does not offer ventilation because many services use an ATV for this purpose c. Portable and easy to deploy i. A small back plate fits behind the patient and allows the piston to snap down directly into the back plate. d. Powered by a small battery at the top of the piston, eliminating need for air hoses 3. Any adjuncts to circulation must be easy to deploy without interrupting high-quality manual CPR compressions. a. Otherwise they will not be used early in the field code. b. If your agency purchases an adjunct, practice with it and make sure it arrives on the scene as early as possible. VIII. Postresuscitative Care A. Postresuscitative care is an important component of caring for cardiac arrest patients. 1. If an effective cardiac rhythm is restored in the field, provide immediate transport. a. If the patient is comatose after ROSC, begin hypothermia treatment immediately. 2. Following is a summary of postresuscitative care: a. Stabilize the cardiac rhythm. i. Administer an antidysrhythmic drug for post–V-fib or post–V-tach. ii. Administer atropine or use a transcutaneous pacemaker for symptomatic bradycardia. b. Normalize the blood pressure. i. Administer a dopamine or norepinephrine infusion to raise the systolic pressure to at least 100 mm Hg. c. Elevate the head to 30° if blood pressure allows. IX. When to Start and When to Stop CPR A. It is a paramedic’s responsibility to start CPR in all patients who are in cardiac arrest, with two exceptions. 1. Do not start CPR if the patient has obvious signs of death (absence of a pulse and breathing) along with any one of the following findings: a. Rigor mortis: Stiffening of the body after death b. Dependent lividity (livor mortis): Skin discoloration caused by pooling of blood c. Putrefaction: Decomposition of the body d. Evidence of nonsurvivable injury i. Decapitation ii. Dismemberment iii. Burned beyond recognition 2. Do not start CPR if the patient and his or her physician have previously agreed not to resuscitate. a. CPR in the terminal stage of an incurable disease only prolongs the patient’s death. b. Documentation of patient’s wishes may not be readily producible by the family or caregiver. i. Do not resuscitate (DNR) orders ii. Medical Orders for Life-Sustaining Treatment (MOLST) forms iii. Advance directives c. In such cases, begin CPR under the rule of implied consent and contact medical control. d. If a valid DNR, MOLST, or living will is produced, resuscitative efforts may be withheld. e. Learn state laws, local protocols, and system standards for treating terminally ill patients. i. Some EMS systems have computer notes on preregistered patients specifying the treatment desired. ii. Other states have specific EMS DNR forms that allow providers to withhold care when the patient, family, and physician have agreed to this in advance. 3. In all other cases, begin CPR on anyone in cardiac arrest. a. Do not stop until one of the following events occurs: i. Patient starts breathing and has a pulse (ROSC). ii. Patient is transferred to another health care provider of equal or more advanced training. iii. You are no longer physically able to perform CPR. iv. Physician assumes responsibility for the patient and gives direction to terminate the resuscitative efforts. 4. Always continue CPR until care is transferred to a physician or higher medical authority. a. Your medical director or a designated medical control physician may order you to stop CPR. b. Every EMS system should have clear standing orders or protocols. B. Terminating resuscitative efforts 1. The 2010 AHA guidelines say the following about lengthy resuscitative efforts and transport: a. Few instances require transporting a nontraumatic cardiac arrest patient who has failed a successfully executed prehospital ACLS resuscitation effort to an emergency department to continue the resuscitation attempt. b. In the absence of mitigating factors, prolonged resuscitative efforts are unlikely to succeed. i. If ROSC of any duration occurs, it may be appropriate to consider extending the resuscitative effort. c. Rare exceptions may include severe prehospital hypothermia and drug overdose. 2. Transporting a deceased patient who is refractory to proper BLS and ALS is usually not appropriate. a. Protocols for pronouncement of death and appropriate transport of the body should be established. C. Termination rules 1. CPR quality is compromised during transport; survival is linked to optimizing scene care. a. For a patient who is receiving only BLS, consider terminating BLS support before transport if all of the following criteria are met: i. The arrest was not witnessed by anyone. ii. No ROSC after three full rounds of CPR and AED analysis. iii. No AED shocks were delivered. b. If ALS personnel are present, consider terminating resuscitative efforts before transport if all of the following criteria are met: i. The arrest was not witnessed by anyone. ii. Bystander CPR was not provided. iii. No ROSC after complete ALS care in the field. iv. No AED shocks were delivered. c. The transportation decision should involve preplanning by the regional and service medical directors. X. Scene Choreography and Teamwork A. Teamwork divides tasks while multiplying the chances for successful resuscitation. Each person has a role, and regular practice leads to better outcomes. 1. All team members must be totally committed to the success of the team rather than to personal achievements. 2. Code team members who are rested, fit, well nourished, have a positive attitude, practice their skills, know the “plays,” and work together as a team are ready to resuscitate patients. 3. To be successful, take the following steps: a. Know the plays expertly and automatically through practice. b. Listen to your “coaches.” c. Have a “practice ethic.” i. Run mock codes or simulations frequently. ii. Collect data on the cumulative time of interruptions of compressions so that the team can improve performance. iii. Measurement and feedback help improve performance. d. Success equals practice, a positive mental attitude, well-designed plays (ie, the algorithms), and excellent coaching. e. The team’s effectiveness is about succeeding as a group. B. Code team member and code team leader roles 1. You should know your role and the roles of other team members. a. This will help you understand your role and anticipate next steps. 2. You must be prepared, have practiced regularly, have mastered the algorithms, and be committed to success. 3. Code team member roles a. Ventilator—manage the airway. i. Duties include: (a) Suctioning (b) Ventilating with a bag-mask device or ATV (c) Inserting an advanced airway device (d) Maintaining manual in-line immobilization of the head and neck b. Active compressor—provide high-quality chest compressions. i. Compress for 2 minutes and be the on-deck compressor for 2 minutes. c. On-deck compressor—at the 2-minute point, be ready to relieve the compressor without any interruption in compressions. i. Duties include: (a) Assisting with application of a mechanical CPR adjunct device (if available) (b) Checking on vital signs (c) Preparing the patient for transport d. Other support personnel i. Analyze the ECG and deliver shocks. ii. Gain venous (IV or IO) access. iii. Provide documentation for the patient care report. iv. Support family members. 4. Code team leader roles a. The code team leader: i. Must know and be able to perform all skills expertly ii. Will occasionally serve as the backup for a team member iii. Is often responsible for making sure everything gets done correctly and at the right time b. The roles of the code team leader may include all of the following: i. Obtain the patient’s history and perform the physical exam. ii. Interpret the ECG. iii. Keep track of time. iv. Make a medication decision following the algorithm. v. Delegate tasks to code team members. vi. Complete documentation after the resuscitation attempt. vii. Talk with medical control. viii. Control the resuscitation scene. c. Code team leaders should: i. Help train future team leaders. ii. Seek to improve the effectiveness of the entire team through continuous quality improvement. iii. Practice after the resuscitation to help prepare for the next code. XI. Plan for a Code A. The following sample plan focuses on a prehospital EMS agency response to a cardiac arrest in a private home, assuming a five-person team that could arrive on different units at different times in the first few minutes. 1. Compressor 1 a. Performs high-quality chest compressions i. At least 100/min, press hard and fast, full chest recoil b. Stays in position and compresses for 2 minutes; then rests for 2 minutes i. For the duration of the time the patient is pulseless c. May assist with application of the Thumper or other adjunct to circulation i. Provided Compressor 2 is continuing uninterrupted compressions 2. Compressor 2 a. Performs high-quality chest compressions i. At least 100/min, press hard and fast, full chest recoil b. Stays in position and compresses for 2 minutes; then rests for 2 minutes i. For the duration of the time the patient is pulseless c. May assist with application of the Thumper or other adjunct to circulation i. Provided Compressor 1 is continuing uninterrupted compressions 3. Ventilator a. Provides ventilations at a ratio of 30:2, ensuring visible chest rise with each ventilation (1 second in duration) b. May need to suction briefly as necessary, then switch over to the ATV as appropriate c. Assists with the transition from BLS airway to advanced airway (not a high priority) d. Once an advanced airway is placed, ventilate 8 to 10 times/min to achieve visible chest rise over a 1-second duration for each ventilation. 4. Code team leader a. Responsible for initial ECG analysis and defibrillation with a single shock (200 J) b. Responsible for overall timing of the code and reassessment after 2 minutes of CPR cycles with the interruption not to exceed 10 seconds c. After the initial shock (or ascertaining “no shock” rhythm), establishes IV or IO access (no medications down the tube) d. Then begins administration of a vasopressor every 3 to 5 minutes i. 1 mg epinephrine 1:10,000, with vasopressin as an acceptable substitute for the first or second—but not both—doses of epinephrine. e. Helps to transition the airway from BLS to an advanced airway and continues with single shocks every 2 minutes if the patient is still in V-tach or V-fib f. Makes the decision with input from the team and medical control to terminate resuscitation if there is no ROSC in the first 15 minutes g. If there is ROSC, administers the appropriate antidysrrhythmic, ensures appropriate ventilations, and helps prepare for transport 5. EMS field supervisor a. Brings in the Thumper or other adjunct and works with a compressor to transition to mechanical CPR compressions with minimal interruption b. Assists the medic with IV or IO, advanced airway placement, and preparation of medications, and contacts medical control, per local protocols B. Managing the field code is complex, but not impossible. 1. Have confidence and expect patients to survive if you come on the scene and someone is already performing CPR. XII. Summary A. The Chain of Survival helps you manage cardiac arrest and includes recognition of a cardiac emergency, early access to 9-1-1, early high-quality CPR by the public or responders, early defibrillation, early advanced life support care, and transport to a hospital for state-of-the-art postresuscitative care. B. CPR guidelines emphasize the importance of high-quality CPR beginning with compressions (push hard and fast, and allow full chest recoil). C. Only consider advanced airways if a basic airway is not adequate or the airway needs better protection due to vomiting. Focus on CPR with high-quality compressions. D. The basic principles of BLS are the same for infants, children, and adults. AHA defines an infant as between the ages of 1 month and 1 year. A child is between age 1 year and puberty. Adulthood is from onset of puberty and older. E. First assess circulation. If the patient has no pulse, start chest compressions at the appropriate rate and depth. F. CPR can be performed with one or two rescuers. Two-rescuer CPR or a team approach is always best. Adult CPR performed alone or with another rescuer has a 30:2 ratio of compressions to ventilations. G. Perform defibrillation as soon as possible in the presence of two rhythms—ventricular fibrillation and pulseless ventricular tachycardia. The chance of success declines rapidly with time. H. With a manual defibrillator, you interpret the cardiac rhythm and determine if defibrillation is needed. An automated external defibrillator does this for you. I. Defibrillation is indicated for patients in nontraumatic cardiac arrest who are older than 1 month. If you are using an automated external defibrillator on a child between age 1 year and the onset of puberty, use pediatric-sized pads and a dose-attenuating system (energy reducer) if available. J. The ACLS algorithm separates the treatment approach into two basic pathways: shockable rhythms (ventricular fibrillation or ventricular tachycardia) or nonshockable rhythms (asystole or pulseless electrical activity). K. For all arrests, regardless of the rhythm, consider and treat reversible causes as appropriate. L. For asystole or pulseless electrical activity, do not deliver shocks. M. Certain devices may be used as adjuncts to circulation to help improve compression quality, including the impedance threshold device, mechanical piston device, and load-distributing band. N. If an effective cardiac rhythm is restored in the field, transport immediately. If the patient is comatose after ROSC consider hypothermia treatment depending on protocol. O. Terminating resuscitative efforts in an adult with a prehospital cardiac arrest should follow the ALS termination of resuscitation rule. P. Teamwork divides tasks while multiplying the chances for a successful resuscitation. Q. Every team member and the team leader should know all the roles during a resuscitation attempt. Post-Lecture This section contains various student-centered end-of-chapter activities designed as enhancements to the instructor’s presentation. As time permits, these activities may be presented in class. They are also designed to be used as homework activities. Assessment in Action This activity is designed to assist the student in gaining a further understanding of issues surrounding the provision of prehospital care. The activity incorporates both critical thinking and application of paramedic knowledge. Instructor Directions 1. Direct students to read the “Assessment in Action” scenario located in the Prep Kit at the end of Chapter 39. 2. Direct students to read and individually answer the quiz questions at the end of the scenario. Allow approximately 10 minutes for this part of the activity. Facilitate a class review and dialogue of the answers, allowing students to correct responses as may be needed. Use the quiz question answers noted below to assist in building this review. Allow approximately 10 minutes for this part of the activity. 3. You may wish to ask students to complete the activity on their own and turn in their answers on a separate piece of paper. Answers to Assessment in Action Questions 1. Answer: A. Intubate early Rationale: Even brief disruptions of CPR can cause diminished coronary artery perfusion pressure, thereby decreasing blood flow to and oxygenation of myocardial tissues. An ischemic heart muscle is less likely to be susceptible to resuscitation efforts. Oxygen and ventilator support may be effectively provided using bag-mask ventilation. 2. Answer: A. True Rationale: Studies have shown that rescuers who become fatigued have decreases in the quality of compressions after 2 to 5 minutes. When two or more rescuers are present, the recommendation is that the compressor should be rotated after five cycles or 2 minutes of compressions. Switch time should be limited to no more than 5 to 10 seconds. Given that compressions cannot achieve normal cardiac output, any impediments to high-quality compressions should be minimized. 3. Answer: C. You witness the patient arrest after connecting the cardiac monitor/defibrillator Rationale: Although the heart is more receptive to defibrillation in the first seconds of an arrest when ventricular fibrillation/ventricular tachycardia is present, unless you are prepared to deliver the shock immediately, high-quality CPR should be performed prior to defibrillation. The AED should be attached as quickly as possible because the chance for successful defibrillation decreases by 7% to 10% every minute. Particularly in arrests that are not witnessed or if you did not witness high-quality CPR being performed, the heart needs to be prepared by providing perfusion and oxygenation of the heart muscle before defibrillation occurs. 4. Answer: D. None of the above Rationale: Although there may be some special circumstances or modifications that need to be made, defibrillation is not contraindicated for these reasons. If the patient is wet or submerged, he or she should be removed from the water and dried before application of electrodes or shock delivery. Pacemakers and automatic implantable cardioverter defibrillators should be avoided by moving placement of the electrodes a few inches from the device(s). There are appropriate pediatric and infant pads, as well as attenuators, and these should be used when available. 5. Answer: B. False Rationale: The majority of successful defibrillations require a minute or more to produce a return of spontaneous circulation (ROSC), and a pulse may not be immediately detectable following shock delivery. Compressions should be initiated after defibrillation. Analysis of the patient’s rhythm and pulse check should be performed following five cycles or 2 minutes of CPR. Use of defibrillator pads or electrodes allows ECG monitoring throughout the arrest and minimizes disruption of compressions. 6. Answer: C. Defibrillation Rationale: Defibrillation is appropriate for the patient in ventricular fibrillation/ventricular tachycardia. Asystole and pulseless electrical activity are considered nonshockable rhythms, and emphasis should be placed on restoring perfusion, oxygenation, and determining potential causes. 7. Answer: C. Pulmonary embolism Rationale: On the basis of the history of recent hip surgery, you should have a high index of suspicion that pulmonary embolism is the likely cause of the patient’s arrest. The patient was less mobile, providing the opportunity for pulmonary embolism formation. The patient may have also been less mobile due to sedation secondary to her prescription pain medications. Potential for toxins should also be considered based on the age of the patient and the risk for unintended overdose of the narcotic pain medication. This may have resulted in respiratory arrest or prolonged hypoxia. The patient also takes medication for hypothyroidism. Depending on medication compliance and therapeutic levels, she may have also had diminished circulation in peripheral vessels, further increasing the potential for pulmonary embolism. Additional Questions 8. Rationale: Due to the multiple tasks required during resuscitation and the importance of minimal disruption of compressions, role assignment and practice multiply the chances of a successful resuscitation. Knowing your role, as well as the roles of others, in the field resuscitation allows you to anticipate and plan for next steps as you progress through the resuscitation. Regular practicing of the skills you are trained for and authorized to perform improve your success when you are called on to participate. You also have the benefit of a global perspective of the management of the field resuscitation when you are familiar with treatment algorithms and patient care protocols. Effective choreography minimizes disruption of care and avoidable delays in treatment. 9. Rationale: In both rules, a patient experiencing an unwitnessed arrest prior to the arrival of EMS or emergency responders is unlikely to be successfully resuscitated. This is particularly true if no bystander CPR has been provided and the heart, brain, and other vital organs have experienced long periods without perfusion. The absence of a shockable rhythm further supports the unlikelihood of a heart that would be receptive to resuscitation efforts or the presence of an underlying condition that would make prolonged resuscitative efforts futile. If available, full ALS care should be attempted prior to moving the patient to the ambulance and before termination of efforts are considered. In this case, the patient experienced an unwitnessed arrest, received no bystander CPR, and no shockable rhythms were detected once the AED was applied. The potential for successful resuscitation, even with prolonged efforts, is unlikely. Assignments A. Review all materials from this lesson and be prepared for a lesson quiz to be administered (date to be determined by instructor). B. Read Chapter 40, Management and Resuscitation of the Critical Patient, for the next class session. Unit Assessment Keyed for Instructors 1. Identify the five links of the Chain of Survival. Answer: The Chain of Survival comprises five vital links. These include early access to emergency care, early high-quality CPR, early defibrillation, early advanced life support care, and transport to a hospital that can provide state-of-the-art postresuscitation care. (pp 1851-1852) 2. Describe how allowing full chest recoil while performing CPR can enhance coronary blood flow. Answer: While performing CPR, some negative pressure develops in the chest as the sternum and ribs rebound to their normal position during the relaxation phase. The negative pressure allows blood to return to the heart. When a greater amount of negative pressure can be achieved in the chest, a greater amount of blood flow returns to the heart. This increased blood return to the heart permits a larger amount of blood to be circulated to the coronary arteries with each compression. (p 1854) 3. What steps should be taken to ensure high-quality CPR? Answer: It is important to always provide high-quality CPR. High-quality CPR consists of a compression rate of at least 100 per minute, a compression depth of a least 2 inches for adults or one third the depth of the chest in infants and children, allowing for complete chest recoil after each compression, minimizing interruptions in chest compressions, and avoiding excess ventilation. (p 1856) 4. Identify common causes of respiratory problems that can lead to cardiopulmonary arrest in children. Answer: In most cases, cardiac arrest in infants and children is secondary to respiratory arrest. Several respiratory problems can lead to cardiopulmonary arrest in children and include: blunt or penetrating trauma; infections of the respiratory tract or other organ system; foreign body obstruction; drowning; electrocution; poisoning or drug overdose; and sudden infant death syndrome. (pp 1857-1858) 5. At what point during a cardiac arrest should an AED be attached? Answer: If you witness the cardiac arrest, begin CPR starting with chest compressions and attach the AED as soon as possible. However, if the cardiac arrest was unwitnessed, particularly if the call-to-arrival time is longer than 4 minutes, perform five cycles (2 miniutes) of CPR prior to applying the AED. (p 1862) 6. Which vasopressors are recommended for use during a cardiac arrest with ventricular fibrillation or pulseless ventricular tachycardia? Answer: The AHA recommends the administration of epinephrine and/or vasopressin during a cardiac arrest. Epinephrine is given as a 1 mg IV push. This dose may be repeated at three to five minute intervals as long as the patient remains pulseless. Vasopressin is given as a 40 unit IV push. A single dose of vasopressin may be substituted for either the first or second dose of epinephrine, but not both. (p 1868) 7. What are the two antidysrhythmic agents that may be administered during a cardiac arrest with ventricular fibrillation or pulseless ventricular tachycardia? Answer: The first antidysrhytmic that can be used in this situation is amiodarone. Amiodarone is given as a 300 mg IV bolus. If needed, a second bolus of 150 mg may be given 3 to 5 minutes following the initial dose. Lidocaine can be used if amiodarone is unavailable. The initial dose of lidocaine is 1 to 1.5 mg/kg, which can be followed by repeated doses of 0.5 to 0.75 mg/kg at 3 to 5 minute intervals, up to a maximum of three doses or 3 mg/kg. (pp 1868-1869) 8. Which medications should be administered when treating a patient in pulseless electrical activity or asystole? Answer: Drug therapy for patients in pulseless electrical activity or asystole includes a vasopressor such as epinephrine or vasopressin. As in the treatment of ventricular fibrillation or pulseless ventricular tachycardia, epinephrine is given as a 1 mg IV push. This dose may be repeated at three to five minute intervals as long as the patient remains pulseless. Vasopressin is given as a 40 unit IV push. A single dose of vasopressin may be substituted for either the first or second dose of epinephrine, but not both. (p 1869) 9. Describe how the impedance threshold device (ITD) works. Answer: The ITD has been shown to enhance the vacuum in an adult’s chest, which forms during the chest recoil phase of CPR. This vacuum pulls air into the lungs and air into the heart. The ITD selectively prevents unnecssary air from entering the chest, thereby maximizing the vacuum during the recoil phase of the compression, and increasing blood return to the heart. (p 1870) 10. Under what circumstances should you not start CPR? Answer: CPR should not be initiated if the patient has obvious signs of death such as absence of a pulse and breathing, along with any one of the following: rigor mortis; dependent lividity (livor mortis); putrefaction, and evidence of a nonsurvivable injury such as decapitation, dismemberment, or burned beyond recognition. (p 1872) Unit Assessment 1. Identify the five links of the Chain of Survival. 2. Describe how allowing full chest recoil while performing CPR can enhance coronary blood flow. 3. What steps should be taken to ensure high-quality CPR? 4. Identify common causes of respiratory problems that can lead to cardiopulmonary arrest in children. 5. At what point during a cardiac arrest should an AED be attached? 6. Which vasopressors are recommended for use during a cardiac arrest with ventricular fibrillation or pulseless ventricular tachycardia? 7. What are the two antidysrhythmic agents that may be administered during a cardiac arrest with ventricular fibrillation or pulseless ventricular tachycardia? 8. Which medications should be administered when treating a patient in pulseless electrical activity or asystole? 9. Describe how the impedance threshold device (ITD) works. 10. Under what circumstances should you not start CPR?