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ACLS Algorithms: From Theory to Practice

ACLS Algorithms: From Theory to Practice

Photo of Greta

by Greta Kviklyte

Life Saver, AMC
Co-authored by Kim Murray, RN, M.S.

posted on Apr 28, 2023, at 8:15 am


To decrease the risk of mortality in cases of cardiac arrest or other cardiovascular emergencies, it is crucial to have a strong understanding of ACLS algorithms. National Heart, Lung, and Blood Institute reports that over 350,000 individuals experience out-of-hospital cardiac arrest each year in the United States, with an additional 209,000 cases occurring in hospitals. However, survival rates are often as low as 10 to 12 percent, depending on where the arrest occurs. These statistics emphasize the significance of remaining knowledgeable about ACLS algorithms and following their best practices.

Every minute that passes between the onset of cardiac arrest and the start of CPR and ACLS measures can significantly increase the likelihood of negative outcomes.

Therefore, being up-to-date with ACLS guidelines is crucial for saving lives. However, the demands and stress of working in healthcare facilities can make it challenging for providers to stay informed. To overcome this challenge, healthcare professionals should frequently review the algorithms and adopt best practices to help commit them to memory.

Mastering the Key Elements of ACLS Algorithms for Cardiac Emergencies

ACLS algorithms provide detailed guidelines for the management of acute coronary syndrome, bradycardia with a pulse, and tachycardia with a pulse. Although there are some minor variations, all algorithms recommend similar actions, such as:

  • Completing the ABCD’s of ACLS and preparing for the possibility of cardiac arrest. ABCD refers to Airway, Breathing, Circulation and Differential Diagnosis.
  • Administering morphine, nitroglycerin, oxygen, and aspirin when required.
  • Obtaining a 12-lead EKG.
  • Implementing adjunctive therapies for ST elevation or referring the patient to the emergency department for further lab work and continuous monitoring of heart rhythms.
  • Other interventions may be necessary, and consultation with cardiology for cardiac catheterization may be required, depending on the severity of the condition.

Highlights of ACLS for Stroke

ems-assiting-patient-on-a-stretcherStrokes are a significant cause of mortality in the United States, claiming around 140,000 lives each year, with someone suffering from a stroke every 40 seconds. According to NIH, the majority of strokes are caused by a blockage in blood flow to the brain, and they cost over $34 billion per year. If left untreated, strokes can cause severe physical damage, cognitive impairment, and even death. However, ACLS algorithms include a series of protocols designed to reduce the risk of poor outcomes from strokes. Key highlights include:

  1. Emergency medical technicians are required to conduct an assessment of the patient’s stroke symptoms before transport to the hospital. This assessment includes documenting the time of occurrence, the severity of symptoms, and checking glucose levels. Additionally, EMTs should inform hospital staff of the patient’s condition before arrival.
  2. Once the patient arrives at the hospital, ACLS algorithms recommend conducting a comprehensive assessment of the patient’s vital signs and heart function. If necessary, treatment for hypoxia and extreme glucose levels should be administered. An MRI of the brain should be ordered, and the stroke team should be activated.
  3. The medical team specializing in treating stroke should conduct a thorough assessment of the patient’s neurological condition, review their medical history, and examine their symptoms.
  4. Based on the results of advanced imaging, the stroke team may consider fibrinolytic therapy or admission to an ICU or stroke unit.

The Primary Algorithm

ACLS provides healthcare professionals with a standardized approach to treating patients in a way that improves their likelihood of survival. As previously mentioned, there are slight variations in the algorithm depending on the suspected cause of the emergency. However, the primary algorithm remains consistent and is as follows:

  1. To start CPR, healthcare providers should first attach the monitor or defibrillator and administer oxygen. However, in cases of out-of-hospital cardiac arrest, this may not be possible, and standard CPR procedures should be initiated. If healthcare providers are unable to provide mouth-to-mouth resuscitation, they can perform hands-only CPR.
  2. Decide whether the rhythm is shockable or not. Pulseless electrical activity (PEA) and asystole are examples of non-shockable rhythms. Shockable rhythms, including ventricular fibrillation (VF) or polymorphous ventricular tachycardia (pVT), require a shock to be treated.
  3. No matter if a shock was given or not, the subsequent step is the same. It includes performing CPR for two minutes and establishing an IV or IO access. Patients with a non-shockable rhythm should be given epinephrine at this stage. On the other hand, those with shockable rhythms may receive another shock, but after that, CPR should continue for two minutes, followed by the administration of epinephrine.
  4. The main distinction is straightforward: administering epinephrine is given after two minutes of diagnosing non-shockable rhythms, while for shockable rhythms, epinephrine is given after four minutes.
  5. If the individual’s heart continues to show a shockable rhythm and spontaneous circulation has not been restored, perform CPR for two more minutes and administer amiodarone. Then, focus on addressing any underlying conditions that may have led to cardiac arrest.
  6. If a non-shockable rhythm is detected and epinephrine is administered, an additional two minutes of CPR should be performed. After that, the healthcare providers should treat any reversible causes of the arrest.
  7. Another significant difference in the overarching ACLS algorithms is the use of amiodarone. Amiodarone is exclusively given to individuals with shockable rhythms and should not be administered to those with non-shockable rhythms.

It is essential to adhere to the ACLS algorithm until ROSC is achieved or an authorized individual declares death, such as an RN, physician, justice of the peace, or paramedic. This involves conducting chest compressions, administering electric shocks, providing the appropriate medications, and performing rescue breaths. Depending on the number of staff present, it is possible to address the reversible causes of arrest while performing chest compressions or other algorithm steps. The reversible causes of cardiac arrest can be divided into two groups: those starting with “H” and those starting with “T.”

Causes of Cardiac Arrest Beginning with the Letter “H”

Hypoxia is a serious medical condition that occurs when the lungs are unable to function correctly and cannot provide sufficient oxygen to the body’s tissues. The lack of oxygen supply can cause stress and the buildup of lactic acid in muscles. This also results in a decrease in oxygen supply to the heart muscle, leading to possible tissue death and the loss of electrical activity in the heart’s coronary vessels.

The method of treating hypoxia is based on its underlying cause, which may vary from CO exposure, asphyxiation, and lung disorders, to sedation caused by opioid overdose. Typically, it involves establishing an advanced airway, performing rescue breaths as part of CPR and ACLS, and administration of oxygen.

For individuals suffering from carbon monoxide (CO) poisoning, a crucial distinction must be made. CO binds to hemoglobin more tightly than oxygen, so they might get enough oxygen from an advanced airway to achieve ROSC. However, they require immediate treatment in a hyperbaric chamber. A hyperbaric chamber operates at a higher atmospheric pressure, which compels CO molecules to unbind from hemoglobin. Because oxygen binds easily to hemoglobin when pressure is increased with oxygen, normal oxygen perfusion is restored.

Hypovolemia occurs when there is a significant loss of bodily fluids, mainly blood, which results in decreased blood flow and perfusion. This loss of fluids may happen due to different reasons such as gastrointestinal bleeding, severe diarrhea, and vomiting, ongoing dehydration, or excessive sweating. As the body enters a state of shock, the heart becomes weak and eventually stops beating. An analogy that can be used to understand this is a hand-held water pump. If there is enough water in the pump, it will work correctly. However, if the water level decreases, the pump will struggle to move water through the tubes. The same thing happens to the heart, where a decrease in blood volume makes it more difficult for the heart to pump blood throughout the body.

Although chest compressions and rescue breaths can improve blood circulation, treating the underlying cause of hypovolemia is crucial. Treatment methods include administering plasma, IV fluids, blood, and clotting factors, depending on the specific cause of the decreased volume of bodily fluids. For example, an individual with hemophilia and severe blood loss may require the administration of blood products, clotting factors, and pressure to the wound to stop bleeding and increase blood volume.

Hydrogen Ion Buildup. When the concentration of hydrogen ions in the blood is high, it can result in a condition called hydrogen ion buildup, also known as acidosis. The acidic pH level in the body may be due to respiratory or metabolic actions. An acidic pH level indicates a higher concentration of hydrogen ions in any solution. To determine if someone is suffering from acidosis, an arterial blood gas test can be performed, which provides an immediate diagnosis.

Respiratory acidosis can be treated by ensuring proper ventilation and the administration of oxygen. On the other hand, metabolic acidosis is caused by an imbalance in the body’s acid-base balance and can be treated with the administration of sodium bicarbonate.

Hyper/Hypokalemia. Potassium is a crucial electrolyte utilized by the body to facilitate muscle contraction and nerve impulses known as action potentials. When the level of potassium becomes excessively high (hyperkalemia) or too low (hypokalemia), it can lead to cardiac arrest. These conditions may be caused by various factors, such as chronic kidney disease or an excessive consumption of potassium-rich foods. The heart loses the necessary electrolytes needed to contract and conduct electrical signals, resulting in cardiac arrest.

The treatment for either hyperkalemia or hypokalemia depends on whether the level has increased or decreased. Hypokalemia can be treated by administering potassium through an infusion. Hyperkalemia can be treated through dialysis in those with kidney disease, or medications like sodium bicarbonate or calcium.

Hypothermia is a rare cause of cardiac arrest that happens when the body’s core temperature drops considerably below the normal range. The threshold for hypothermia is around 30°C or 86°F, and when the body temperature drops to this level, the cardiac output decreases significantly, increasing the likelihood of cardiac arrest. Treating hypothermia through CPR and defibrillation may be challenging and ineffective in some cases.

The immediate treatment for hypothermia is rewarming the body. However, the order of administering CPR and rewarming may vary depending on the facilities available. If it is possible to use external warming methods such as blankets and heat sources without interfering with the rewarming process, CPR can be initiated. Hypothermia has unique implications in that it may be advisable to delay CPR until rewarming is directed. If no such direction is available, it is recommended to perform ACLS and rewarming simultaneously. Although hypothermia is a cause of cardiac arrest, it is also one of the few conditions where tissue preservation may occur while in a hypothermic state.

Causes of Cardiac Arrest Beginning with the Letter “T”

two-healthcare-professionals-reading-algorithmsA tension pneumothorax is a condition where air enters the space between the protective membranes surrounding the lungs. These membranes are essential for proper lung function, as they create a negative-pressure space through the expansion of the lungs. When perforation occurs, air can enter the space and cause pressure to build up, equalizing the pressure between the pleural space and the atmosphere. As a result, the lungs cannot function correctly, and the person may have difficulty breathing or be unable to draw oxygen into their body.

To cure a tension pneumothorax, the air present in the pleural space should be removed through either needle decompression or a chest tube.

Cardiac tamponade is a medical condition that arises when the pericardial sac, a fluid-filled sac surrounding the heart, fills up with either blood or fluid. The excess fluid causes the heart to experience additional pressure, leading to the constriction of the ventricles, limiting the heart’s capacity to expand and reducing blood flow. The most common cause of cardiac tamponade is perforation of the pericardial sac.

To treat cardiac tamponade, medical professionals must remove the fluid or blood that has accumulated in the pericardial sac. This is done through a procedure called pericardiocentesis, which involves inserting a needle into the sac to drain the fluid. Alternatively, surgical options like thoracotomy may also be utilized.

Toxins. In this article, we only focus on toxins that enter the body through animal bites or consumption of poisonous substances, although it is possible for any substance to become toxic in the bloodstream.

Except for specific antidotes like rattlesnake antivenom, there are currently no particular recommendations for treating toxicity during ACLS. Therefore, treatment can only begin if the toxin is identified and there is a specific antidote available. If the toxin is unknown, it’s not practical to try treatment until a toxicologist has been consulted after the patient has been successfully resuscitated.

Thrombosis happens when a major vessel is blocked, and pulmonary thrombosis occurs when there is a blockage in the pulmonary artery or vein, which is also known as a pulmonary embolism. The heart is unable to receive sufficient blood flow as a result of this blockage. On the other hand, coronary thrombosis occurs when there is a blockage in one of the vessels that provide blood flow to the cardiac tissue. This results in a heart attack or myocardial infarction.

To treat a pulmonary embolism, several options are available, including fibrinolytic therapy, embolectomy, or anticoagulants. Surgical intervention is necessary for the first option, while medications can treat the embolus for the latter. In contrast, treating coronary thrombosis is more complex and involves procedures like angioplasty, stent placement, or even coronary bypass surgery. The severity of the blockage and the probability of its recurrence will determine the best course of treatment.

Keep Your ACLS Certification Updated

The application of ACLS Algorithms can help to reduce mortality from cardiac arrest and improve treatment outcomes in both cardiac arrest and medical emergencies. Although the algorithm is commonly associated with cardiac arrest, it can also be applied to other conditions like stroke, arrhythmias, or heart problems such as heart attack that may lead to cardiac arrest. Therefore, it is important to regularly review and update your ACLS skills to ensure that you are well-equipped to handle any emergency situation.

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About Greta

Greta is a dedicated life saver and a distinguished expert in the field of medical content creation and editing. Her impressive array of certifications in ACLS, CPR, PALS, and BLS underscores her commitment to excellence in the medical field. With over four years of invaluable experience in medical education, Greta plays an indispensable role within the Advanced Medical Certification team, shaping the way healthcare professionals around the world acquire and apply vital knowledge.

Greta's profound expertise serves as the driving force behind the development and distribution of medical content that has significantly enhanced the capabilities of countless healthcare practitioners across the globe.

In addition to her medical qualifications, Greta holds a prestigious academic distinction in Marketing and Global Business from Vilnius University. Her academic journey has been enriched by immersive studies in Slovakia and Portugal during her time as an exchange student, providing her with a global perspective that complements her medical expertise.

Beyond her professional commitments, Greta possesses a genuine passion for global exploration, with a particular focus on immersing herself in diverse cultures and appreciating the intricacies of the natural world. While residing in Vilnius, Lithuania, she continues to make substantial contributions to the field of medical education, leaving an indelible mark on the sector.

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