Advanced life support
Advanced life support (ALS) is a level of emergency medical care that extends beyond basic life support (BLS) by incorporating advanced interventions to manage life-threatening conditions, particularly cardiac arrest, in prehospital and in-hospital settings.[1][2] These interventions include defibrillation, advanced airway management, intravenous or intraosseous access for medication administration, continuous physiological monitoring, and treatment of reversible causes of arrest, all aimed at restoring spontaneous circulation and improving patient survival.[3][4] The core principles of ALS emphasize high-quality cardiopulmonary resuscitation (CPR) with minimal interruptions, early rhythm assessment and defibrillation for shockable rhythms (such as ventricular fibrillation or pulseless ventricular tachycardia), and timely administration of drugs like epinephrine to support circulation.[1][2] Guidelines from organizations like the Resuscitation Council UK and the American Heart Association, updated in 2025, highlight the importance of team coordination, waveform capnography for CPR quality feedback, and post-resuscitation care to optimize neurological outcomes.[1][2] ALS protocols also incorporate shared decision-making, early warning systems to prevent deterioration, and considerations for special populations, such as opioid-associated arrests or extracorporeal CPR in refractory cases.[1]Overview
Definition and Principles
Advanced life support (ALS) represents a sophisticated tier of emergency medical care that builds upon basic life support (BLS) by incorporating invasive procedures to restore and maintain vital organ perfusion and oxygenation in critically ill patients, particularly those in cardiac arrest, profound shock, or acute respiratory failure.[5][1] These interventions include endotracheal intubation for airway management, intravenous or intraosseous access for fluid and pharmacological administration, and manual defibrillation to treat life-threatening arrhythmias.[5][2] ALS is designed for use by trained healthcare professionals, such as paramedics and physicians, in both pre-hospital and in-hospital settings to address scenarios where BLS alone is insufficient to reverse deterioration.[6] The foundational principles of ALS revolve around the ABCDE systematic approach, which prioritizes airway patency, effective breathing support, circulatory stability, neurological assessment (disability), and full patient exposure for comprehensive evaluation.[7][1] This framework guides rapid, sequential assessment and intervention to identify and treat reversible causes of collapse, minimizing interruptions in care and preventing secondary organ damage through continuous monitoring of physiological parameters like end-tidal CO2 and blood pressure.[5] Emphasis is placed on high-quality, time-sensitive actions—such as achieving return of spontaneous circulation within minutes—to optimize outcomes, with ongoing evaluation to adapt interventions based on patient response.[5] The 2025 guidelines from the Resuscitation Council UK and American Heart Association reinforce these principles, with added emphasis on correct defibrillator pad placement and enhanced post-arrest care.[1][2] ALS operates within legal and ethical frameworks that respect patient autonomy and resource allocation, including adherence to do-not-resuscitate (DNR) or do-not-attempt-resuscitation (DNAR) orders, which must be honored when valid advance care planning documents like Physician Orders for Life-Sustaining Treatment (POLST) are present.[8] These principles are informed by the chain of survival concept, a sequence of linked actions encompassing early recognition and activation of emergency response, high-quality CPR, rapid defibrillation, advanced post-arrest care, and recovery support to maximize survival and neurological intactness.[9] Ethically, shared decision-making with patients or surrogates guides initiation or termination of ALS, balancing beneficence with nonmaleficence in high-stakes scenarios.[8] In terms of impact, ALS has demonstrated survival benefits over BLS alone in some studies, including a two-fold increase in short-term and long-term survival to hospital discharge, particularly when integrated with bystander efforts and for shockable rhythms.[10] However, evidence on long-term outcomes remains mixed across contexts.Distinctions from Basic Life Support
Advanced life support (ALS) builds upon the foundational interventions of basic life support (BLS) by incorporating more sophisticated, often invasive techniques to address life-threatening emergencies, particularly in cardiac arrest scenarios. BLS is primarily limited to non-invasive maneuvers such as chest compressions, rescue breaths, and the use of automated external defibrillators (AEDs) to maintain circulation and oxygenation until advanced help arrives.[11] In contrast, ALS extends these efforts with advanced airway management devices like endotracheal intubation or supraglottic airways, administration of antiarrhythmic and vasopressor drugs such as epinephrine and amiodarone, and invasive monitoring tools including arterial lines and capnography to guide resuscitation efforts.[11][12] These enhancements allow ALS providers to target underlying rhythms and physiological derangements more precisely, transitioning from supportive care to therapeutic intervention.[12] Recent studies indicate that while ALS improves short-term outcomes like return of spontaneous circulation, evidence for long-term survival benefits over BLS is mixed, with some research suggesting no additional advantage or potential harm due to delays in transport.[13][14] The integration of ALS has demonstrated measurable improvements in clinical outcomes over BLS alone, particularly in out-of-hospital cardiac arrest (OHCA) cases. For instance, a prospective study of 1,423 adult non-traumatic OHCA patients in Taipei found that those receiving ALS achieved a return of spontaneous circulation (ROSC) rate of 29%, compared to 21% for those treated with BLS-D (basic life support with defibrillation), representing an odds ratio of 1.51 (95% CI 1.15-2.00).[15] This absolute increase underscores ALS's role in enhancing immediate resuscitation success, though long-term survival benefits may vary based on factors like response time and patient characteristics.[15] Meta-analyses of pre-hospital care further support that ALS can elevate ROSC and short-term survival rates by addressing reversible causes more effectively than BLS's supportive measures.[16] ALS is typically reserved for settings where trained professionals can deliver care, differing markedly from BLS's applicability to lay responders in community or immediate response contexts. BLS protocols empower bystanders, first aid providers, or minimally trained individuals to initiate life-saving actions without specialized equipment, emphasizing rapid activation of emergency services.[11] ALS, however, is deployed by paramedics, physicians, or nurses in pre-hospital ambulance environments or hospital settings, where access to medications, advanced diagnostics, and transport capabilities enables sustained intervention during transfer to definitive care.[11] This distinction ensures that ALS complements rather than replaces BLS, with the ABCDE (Airway, Breathing, Circulation, Disability, Exposure) approach in ALS incorporating BLS elements while escalating to targeted therapies.[11] The training requirements for ALS reflect its complexity, demanding significantly more preparation than BLS to equip providers with the skills for high-stakes decision-making. BLS certification, offered by organizations like the American Heart Association, typically involves 4 to 4.5 hours of instruction for initial providers, covering core skills in a classroom or blended format, and is renewable every two years with about 4 hours.[17] In comparison, ALS training, such as Advanced Cardiovascular Life Support (ACLS), requires extensive education spanning 15.5 to 16.5 hours for initial certification, including video prework, hands-on simulations, and scenario-based testing on pharmacology and team dynamics, with renewals taking 8.5 to 9.5 hours.[12] This rigorous threshold ensures that only qualified healthcare professionals undertake ALS, minimizing risks associated with invasive procedures.[12]Historical Context
Origins in Emergency Medicine
The origins of advanced life support (ALS) in emergency medicine trace back to mid-20th-century innovations that extended resuscitation capabilities beyond basic techniques. In the 1950s, researchers at Johns Hopkins University, including William Kouwenhoven, James Jude, and Guy Knickerbocker, developed the first portable external defibrillator, weighing approximately 200 pounds, which enabled closed-chest defibrillation without surgical intervention.[18] This breakthrough, demonstrated in animal and human studies, marked a pivotal shift toward treating cardiac arrest in non-hospital settings by restoring normal heart rhythm electrically.[18] The 1960s saw further advancements in prehospital care, exemplified by the establishment of mobile coronary care units. In 1966, cardiologist Frank Pantridge at the Royal Victoria Hospital in Belfast launched the world's first such unit, equipping an ambulance with a portable defibrillator and monitoring tools to provide immediate intervention for out-of-hospital cardiac events.[19] This initiative dramatically improved survival rates for sudden cardiac arrest by bridging the gap between collapse and hospital treatment, influencing global models of mobile emergency response.[19] Concurrently, the 1966 National Academy of Sciences conference on cardiopulmonary resuscitation standardized CPR techniques, integrating external chest compressions with ventilation and defibrillation to form the foundation of ALS protocols.[20] Foundational events in the United States solidified ALS's role in emergency medicine during the late 1960s. The conference's recommendations spurred the creation of the first paramedic programs, with the Miami Fire Department initiating the nation's inaugural program in 1969 under Dr. Eugene Nagel, training firefighters to deliver advanced interventions like intubation and pharmacology in the field.[21] This program achieved the first successful prehospital revival of a cardiac arrest patient that same year, demonstrating ALS's potential to save lives outside hospitals.[21] ALS concepts spread globally in the 1970s, with European medical communities adopting prehospital defibrillation and mobile units inspired by U.S. and U.K. innovations, though formalized standardization emerged later through the European Resuscitation Council, founded in 1992.[22] In the early 1980s, the Resuscitation Council UK began adapting ALS protocols, leading to standardized training courses by the 1990s.[23] Early implementation faced significant challenges, including limited availability of portable equipment—such as bulky defibrillators and radios—and regulatory hurdles, as fewer than 25% of U.S. cities regulated EMS services by 1966, leading to inconsistent training and vehicle standards.[24] These obstacles slowed widespread adoption, with only a minority of personnel receiving advanced training amid disorganized systems prioritizing transport over medical intervention.[24]Evolution of International Guidelines
The evolution of international guidelines for advanced life support (ALS) began in the 1970s with the formalization of standardized protocols by major organizations, marking a shift toward structured, evidence-informed resuscitation practices. In 1975, the American Heart Association (AHA) launched its Advanced Cardiovascular Life Support (ACLS) program, incorporating drug algorithms for managing cardiac arrest rhythms, including interventions like epinephrine and antiarrhythmics to address pulseless ventricular tachycardia and fibrillation.[18][25] This development built on earlier advancements in defibrillation techniques from the 1960s and 1970s, providing a systematic framework for integrating pharmacological support with electrical therapies. A pivotal advancement occurred in 2000 with the issuance of the first comprehensive consensus guidelines by the International Liaison Committee on Resuscitation (ILCOR), formed in 1992 to promote evidence-based international standards.[26] ILCOR's formation facilitated collaboration among resuscitation councils worldwide, synthesizing global research into unified recommendations updated every five years through systematic reviews of randomized controlled trials (RCTs) and meta-analyses.[26] This evidence-driven approach emphasized the integration of high-quality data to refine ALS protocols, ensuring consistency while allowing for regional adaptations. Major revisions in subsequent decades reflected evolving scientific evidence. The 2010 AHA ACLS guidelines prioritized high-quality cardiopulmonary resuscitation (CPR) with a compression rate of at least 100 per minute, depth of at least 5 cm, and full chest recoil, while stressing the minimization of interruptions to less than 10 seconds to improve coronary and cerebral perfusion.[27] By 2020, ILCOR updates incorporated considerations for double-sequential defibrillation in refractory ventricular fibrillation and extracorporeal membrane oxygenation (ECMO) as a rescue therapy for select refractory cases, based on systematic reviews showing potential benefits in survival for out-of-hospital cardiac arrests.[28] Regional variations exist among key organizations adapting ILCOR consensus. The AHA, focused on U.S. practices, updates its guidelines every five years with an emphasis on integrated systems of care, including rapid response teams.[29] The European Resuscitation Council (ERC) tailors its protocols for European contexts, with the 2015 guidelines highlighting enhanced post-resuscitation care, such as targeted temperature management to improve neurological outcomes.[30] The Australian and New Zealand Committee on Resuscitation (ANZCOR) provides adaptations suited to Australasian healthcare settings, incorporating local epidemiology and resources into ALS algorithms.[31] The evidence basis for these guidelines relies heavily on RCTs and meta-analyses, ensuring recommendations are grounded in high-impact studies. For instance, 2023 AHA focused updates on antiarrhythmic drugs for shock-refractory ventricular fibrillation/pulseless ventricular tachycardia drew from trials like the ARREST study (demonstrating amiodarone's survival benefits) and subsequent analyses, including the ROC ALPS trial, which informed balanced considerations of amiodarone versus lidocaine without a clear superiority in overall outcomes but with subgroup advantages for both in witnessed arrests.[32] The 2025 ILCOR and AHA updates further refined protocols, including suggestions for double sequential external defibrillation and vector change strategies for refractory ventricular fibrillation, as of October 2025.[33][29] This iterative process continues to refine ALS protocols, prioritizing patient-centered metrics like survival with favorable neurology.[32]Core Components
Airway and Breathing Interventions
In advanced life support (ALS), airway and breathing interventions prioritize securing a patent airway and providing effective oxygenation and ventilation to support cerebral and systemic perfusion during cardiac arrest or peri-arrest states. Initial management typically involves bag-valve-mask (BVM) ventilation to deliver oxygen while minimizing interruptions in chest compressions.[34] Advanced techniques, such as endotracheal intubation (ETI) or supraglottic airway (SGA) placement, are considered once basic measures are established, particularly by trained providers to reduce hypoxia risks.[34] Endotracheal intubation remains a primary method for definitive airway control in ALS, involving insertion of an endotracheal tube through the vocal cords to isolate the trachea from the esophagus. Placement should occur without excessive pauses in CPR, ideally under direct visualization, with success rates ranging from 52% to 98% depending on provider experience and patient factors.[34] Confirmation of correct tube position is essential and achieved using quantitative waveform capnography, which detects end-tidal CO2 (ETCO2) with 100% specificity for tracheal placement, though sensitivity may decrease after prolonged arrest due to low pulmonary blood flow.[34] Supraglottic airways serve as rapid alternatives to ETI, particularly in scenarios requiring quick insertion without laryngoscopy. Devices such as the laryngeal mask airway (LMA) or i-gel provide a seal above the glottis, facilitating ventilation while allowing ongoing CPR; SGAs demonstrate faster placement times and potentially higher rates of return of spontaneous circulation (ROSC) compared to ETI in some systems.[34] These are recommended for providers proficient in their use, with backup plans for failed attempts to avoid delays.[34] Ventilation strategies in ALS aim to deliver adequate tidal volumes (approximately 500-600 mL in adults) while preventing hyperventilation, which can compromise coronary perfusion. With BVM, positive end-expiratory pressure (PEEP) valves (5-10 cm H2O) may be incorporated to improve oxygenation, especially in patients with poor lung compliance.[35] Once an advanced airway is secured, asynchronous ventilations are provided at 8-10 breaths per minute (one every 6 seconds), synchronized with visible chest rise to avoid barotrauma.[36] In transport or prolonged resuscitation, mechanical ventilators can maintain these parameters, targeting normocapnia to support hemodynamic stability.[34] Monitoring tools are integral to optimizing airway and breathing interventions. Waveform capnography not only confirms placement but also assesses ventilation quality, with ETCO2 targets of 35-45 mmHg indicating effective gas exchange post-placement; during CPR, values above 10 mmHg (ideally >20 mmHg) correlate with better cardiac output and ROSC likelihood.[34] Pulse oximetry monitors peripheral oxygen saturation (SpO2), aiming for >94% to ensure adequate tissue oxygenation without excessive supplemental oxygen that could induce hyperoxia.[36] Complications of airway interventions include aspiration of gastric contents, particularly with delayed securement, and esophageal intubation if confirmation is inadequate. In difficult airways—characterized by anatomical challenges or limited access—video laryngoscopy enhances first-attempt success rates over direct laryngoscopy, reducing trauma and hypoxia risks.[37] Alternatives like SGAs are preferred initially in such cases to maintain ventilation until expertise allows ETI.[34]Circulation and Defibrillation Techniques
In advanced life support (ALS), circulation is primarily restored and maintained through high-quality cardiopulmonary resuscitation (CPR), which aims to generate adequate cardiac output during cardiac arrest. High-quality CPR involves chest compressions at a rate of 100 to 120 per minute and a depth of 5 to 6 cm in adults, with full chest recoil between compressions and a compression fraction exceeding 80% to minimize interruptions.[38] These parameters, derived from extensive clinical evidence, optimize coronary and cerebral perfusion pressures, improving the likelihood of return of spontaneous circulation (ROSC).[34] End-tidal carbon dioxide (ETCO₂) monitoring during CPR provides a surrogate for CPR quality, with values greater than 10 mm Hg indicating adequate compressions and targets above 20 mm Hg associated with higher ROSC rates.[34] For hypovolemia as a reversible cause of cardiac arrest, intravenous (IV) or intraosseous (IO) fluid resuscitation is essential to restore intravascular volume and support hemodynamic stability. Isotonic crystalloids, such as normal saline or lactated Ringer's, are administered via IV or IO access, with initial boluses of 500 to 1000 mL guided by clinical response and avoiding fluid overload.[34] IO access is particularly valuable in emergencies when IV placement is challenging, offering comparable flow rates and rapid drug/fluid delivery with success rates exceeding 90% in trained hands.[39] This approach addresses circulatory collapse from blood loss or dehydration, integrating with the broader ALS algorithm to treat the underlying "H's and T's."[40] Defibrillation is a cornerstone intervention for shockable rhythms such as ventricular fibrillation (VF) or pulseless ventricular tachycardia (pVT), delivering electrical shocks to depolarize the myocardium and restore sinus rhythm. Biphasic waveform defibrillators are preferred due to their higher efficacy at lower energy levels compared to monophasic devices, with initial shocks recommended at 120 to 200 joules (J) for VF/pVT.[34] Escalating energy strategies (e.g., 200 J, then 300 J, then 360 J) may be employed for refractory VF, as randomized trials show improved termination rates without increased harm.[41] A single-shock approach followed by immediate CPR resumption is emphasized to limit peri-shock pauses, which can reduce survival odds by up to 50% per 5-second delay.[34] For hemodynamically unstable tachyarrhythmias with a pulse, such as unstable supraventricular tachycardia or wide-complex tachycardia, synchronized cardioversion is indicated to deliver a timed shock on the R-wave, preventing induction of VF. Initial energies start at 50 to 100 J for narrow-complex rhythms, 100 J for monomorphic wide-complex tachycardia, and ≥200 J (biphasic) for atrial fibrillation or flutter, escalating as needed; use maximum energy for polymorphic ventricular tachycardia based on device specifications.[34] Sedation is considered if the patient is conscious and time permits, prioritizing rapid intervention to avert deterioration.[39] These protocols, updated in the 2025 guidelines, reflect evidence from international consensus reviews showing first-shock success rates over 90% with biphasic devices at ≥200 J for certain atrial arrhythmias.[40] Advanced monitoring enhances circulation management by providing real-time data to guide interventions. Invasive arterial blood pressure monitoring via arterial lines allows detection of ROSC through waveform appearance or rising diastolic pressures during ongoing CPR, enabling earlier cessation of compressions if spontaneous circulation returns.[34] Electrocardiogram (ECG) interpretation is fundamental for distinguishing shockable rhythms (VF/pVT) from non-shockable ones (asystole/PEA), with continuous monitoring to assess rhythm changes post-defibrillation or drug administration.[42] Point-of-care ultrasound (POCUS) may complement ECG by evaluating cardiac activity without interrupting compressions, though it should not delay defibrillation.[34] Mechanical chest compression devices, such as the LUCAS system, serve as adjuncts in scenarios requiring prolonged resuscitation efforts, such as extended transport or provider fatigue. These piston-driven devices deliver consistent compressions at 100 to 102 per minute and 5 to 6 cm depth, maintaining quality when manual CPR is unsustainable.[43] However, routine use is not recommended outside specific contexts due to insufficient evidence of survival benefit over manual CPR in most out-of-hospital arrests, though they are widely adopted in EMS for logistical advantages.[40] Transition to manual compressions is advised for rhythm checks or defibrillation to avoid delays.[43]Vascular Access and Pharmacological Interventions
In advanced life support (ALS), establishing rapid vascular access is essential for delivering medications and fluids during cardiac arrest and peri-arrest states, with intravenous (IV) access preferred as the initial route due to its reliability and speed in most clinical settings.[44] Peripheral IV cannulation, typically in large veins such as the antecubital or external jugular, allows for immediate drug administration and is recommended first by the American Heart Association (AHA).[34] If peripheral IV access cannot be rapidly obtained, intraosseous (IO) access serves as a viable alternative, enabling equivalent drug delivery through devices inserted into the proximal tibia, humerus, or sternum, with no significant differences in outcomes compared to IV routes in randomized trials.[34] Examples of IO systems include the EZ-IO for humeral or tibial insertion and the FAST1 for sternal access, both facilitating rapid infusion rates up to 250 mL/min for fluids and medications.[45] Central venous access, such as via internal jugular or subclavian veins, is reserved for prolonged resuscitation or when peripheral and IO routes fail, though it carries higher risks of complications like pneumothorax and should not delay initial therapy.[34] Pharmacological interventions in ALS primarily target vasopressor support and antiarrhythmic therapy to improve return of spontaneous circulation (ROSC) and hemodynamic stability. Epinephrine remains the cornerstone vasopressor, administered at a dose of 1 mg IV or IO every 3-5 minutes during cardiac arrest, enhancing coronary and cerebral perfusion but without proven long-term neurological benefits.[46] For shock-refractory ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT), amiodarone is recommended as the first-line antiarrhythmic, with an initial bolus of 300 mg IV or IO, followed by a second dose of 150 mg if needed, improving short-term survival to hospital admission.[46] Other agents, such as lidocaine (1-1.5 mg/kg IV/IO initial dose), may be used as alternatives to amiodarone in refractory VF/VT, though evidence favors amiodarone for better outcomes.[46] Fluid therapy in ALS focuses on volume resuscitation for hypotension or shock, using crystalloids like normal saline or lactated Ringer's in boluses of 500-1000 mL IV, titrated to maintain mean arterial pressure (MAP) above 65 mm Hg post-ROSC or in peri-arrest hypovolemia.[47] In distributive shock such as sepsis, initial fluid boluses precede vasopressors, with norepinephrine preferred as the first-line agent at infusions starting at 0.1-0.5 mcg/kg/min IV to support perfusion without excessive vasoconstriction.[34] Vasopressin offers no survival advantage over epinephrine alone in cardiac arrest and is not routinely recommended.[44] Dosing in ALS requires careful consideration of patient factors, with most vasopressors and antiarrhythmics using fixed adult doses (e.g., epinephrine 1 mg regardless of weight) to ensure rapid administration, though weight-based adjustments apply to agents like lidocaine (1-1.5 mg/kg).[46] Contraindications include avoiding beta-blockers in bradycardic states due to risk of further hypotension, and calcium channel blockers like verapamil in wide-complex tachycardia of unknown origin to prevent hemodynamic collapse.[34] All interventions emphasize minimizing delays, as timely access and drug delivery correlate with improved ROSC rates in observational data.[34]| Medication | Indication | Dose and Route | Source |
|---|---|---|---|
| Epinephrine | Cardiac arrest (all rhythms) | 1 mg IV/IO every 3-5 min | AHA 2025 Algorithm |
| Amiodarone | Refractory VF/pVT | 300 mg IV/IO bolus; repeat 150 mg | AHA 2025 Algorithm |
| Lidocaine | Alternative for refractory VF/pVT | 1-1.5 mg/kg IV/IO; repeat 0.5-0.75 mg/kg | AHA 2025 Algorithm |
| Norepinephrine | Septic or post-ROSC shock | Infusion 0.1-0.5 mcg/kg/min IV | AHA Part 9 |