The ABCDE approach explainedBMJ 2016; 355 doi: https://doi.org/10.1136/sbmj.i4512 (Published 24 October 2016) Cite this as: BMJ 2016;355:i4512
The resuscitation room (“resus”) in the emergency department is where patients with immediately life threatening illnesses and injuries are managed. For a medical student it can be a daunting environment to enter for the first time: the resus team has to move quickly to keep patients alive, and it can be hard to keep up to speed with what’s going on.
Despite what might seem like chaos, the team uses a systematic method for managing all acutely ill patients called the ABCDE (A-E) approach. It is a way of systematically assessing each of a patient’s vital systems—airway, breathing, circulation, disability, and exposure.
The aim of the assessment is to identify and stabilise the patient’s most life threatening problems first, before moving on to the next vital system to achieve some clinical improvement to buy time for further treatment and making a diagnosis.1 Once the team has completed an A-E assessment, it repeats the steps to reassess each system to determine if clinical features are improving or deteriorating.
As a student, you will not be expected to manage patients in resus on your own, but an understanding of the steps entailed in an A-E assessment (table 1⇓) before your first placement in the emergency department can help you follow the interventions. As a foundation doctor, you will learn more about the specifics of giving lifesaving treatment by attending the compulsory advanced life support course. For more detailed information on how to perform the steps of an A-E assessment, read the guidance provided by the Resuscitation Council UK.1
This article uses a clinical scenario to show you how the team in resus would use the A-E approach to manage a critically ill patient who has been in a house fire.
Box 1: The A-E in reality
In reality, the A-E process is performed simultaneously, rather than in a linear fashion—that is, establishing intravenous access, administering high flow oxygen and fluids, and checking blood glucose levels are often done at the same time by various members of the team. However, a team leader (usually a senior doctor) should have a clear overview of what the team is doing and continue to think through the A-E approach in a systematic, logical way. This ensures nothing important is missed and simplifies what patients require in an emergency situation, focusing on dealing with the most important issues first.
Box 2: Who’s who in the resuscitation team?
This is usually a senior emergency department doctor (registrar or consultant) who stands at the foot of the bed and leads the patient’s care. Team leaders have a hands-off approach so that they can maintain situational awareness and delegate jobs to the rest of the team.
Emergency medicine doctors (foundation year 2 doctors, core medical trainees, and emergency medicine registrars)
They are often among the first at the bedside in an acute situation. They might carry out the initial A-E assessment and perform practical tasks such as establishing intravenous access, obtaining arterial blood gases, and carrying out catheterisation. They also prescribe necessary drugs and fluids and request investigations such as chest radiography.
Emergency medicine nurses
They might put patients on a cardiac monitor, take vital signs, and administer analgesia and fluids. They can carry out bedside tests such as electrocardiography, blood glucose measurement, and urine analysis, and assist with procedures such as catheterisation.
Other specialty doctors who can be called to assist the resus team
Anaesthetist—leads airway management, making sure there is a stable patent airway, and is part of the cardiac arrest and trauma team.
Medical team—(registrar, foundation doctors, and core trainees) part of the cardiac arrest team.
Surgical team—(registrar, foundation doctors, and core trainees) part of the trauma team. The orthopaedics, neurosurgery, plastics, and maxillofacial team may also form part of the trauma team, depending on the hospital.
The A-E approach in action
You are a medical student on your first night shift with the resuscitation team in the emergency department. It is 2300 hours, and a 60 year old man (Mr B) is brought in by ambulance having been rescued from a house fire. The ambulance crew hands over to the emergency department junior doctor and nurse and tells them that the man was found in his living room, which was filled with smoke. The nurse is concerned that she cannot record his blood pressure and that Mr B has not received any analgesia.
What should the team do now?
2300 hours: the junior doctor starts by assessing Mr B’s airway. The quickest way to do this is by talking to the patient to see if he can respond. If he is able to talk back in a clear voice, the airway is deemed patent and you can move on to step B.
In this scenario, the patient’s history should give you a high index of suspicion for a smoke induced inhalation injury, which can result in airway oedema and obstruction. The junior doctor inspects for signs of smoke inhalation injury, such as burns to the mouth, nose, and face; singed nasal hairs; and the presence of carbonaceous sputum. This is followed by listening for signs of impending airway obstruction such as hoarseness in the voice, stridor, or snoring. The nurse undresses the patient and attaches him to a monitor.
2302 hours: Mr B is able to talk but with a hoarse voice and has partial thickness burns to his face.
The junior doctor asks the nurse to give 15 L high flow oxygen through a non-rebreather mask—this should be done for all critically ill patients. As there is potential for rapid airway obstruction, the junior doctor calls the emergency department registrar for help and the anaesthetist in case the patient needs to be intubated.
The junior doctor carries out a swift, basic respiratory examination using the look, listen, and feel approach. Meanwhile, the nurse records the oxygen saturation (SpO2) and measures the patient’s respiratory rate. Respiratory rate is an extremely sensitive marker of critical illness and an important predictor of serious events such as cardiac arrest and admission to the intensive care unit.34 Despite the importance of respiratory rate, it is often neglected or poorly documented. If in doubt, it should be counted for a full minute.
2306 hours: Mr B has a respiratory rate of 22 breaths/min, SpO2 of 99% on high flow oxygen, and is using accessory muscles to breathe.
The junior doctor keeps the patient on oxygen and obtains arterial blood gases (ABG) to determine the effectiveness of Mr B’s gas exchange, acid-base status, and carbon monoxide level, as Mr B has been in a house fire. The ABG results show: pH 7.38, pCO2 4.9 kPa, pO2 11.3 kPa, HCO3 (bicarb) 23 mmol/L—which are within the normal parameters. Mr B’s HbCO (carboxyhaemoglobin) is 1.4%: a normal level of HbCO is <5% in non-smokers, so Mr B’s HbCO level is within the normal parameters.
The junior doctor looks for signs of shock—defined as circulatory failure leading to hypoperfusion of vital organs. These are tachycardia, tachypnoea, cool peripheries, increased capillary refill time, and hypotension. Acute confusion and reduced urine output are also signs of shock, which might become more evident later on. It is important to appreciate that some patients may not exhibit these signs until late on in their clinical course.
A normal blood pressure in particular can be falsely reassuring, especially in young patients whose physiological reserve and compensatory mechanism can withstand prolonged periods of shock without a substantial drop in blood pressure. When assessing the circulation, an abdominal examination can also show potential surgical causes for shock—for example, perforated viscus or ruptured abdominal aortic aneurysm.
2308 hours: Mr B has a heart rate of 112 beats/min, blood pressure of 84/40 mm Hg, and is cool and clammy.
Mr B is showing signs of shock, as indicated by the observations above. Although the cause of the shock is unclear at this stage, the junior doctor prescribes an initial bolus of 500 mL of crystalloid solution over 15 minutes, as guided by the National Institute for Health and Care Excellence (NICE) algorithm for fluid therapy in adults.5 The healthcare assistant gains intravenous access and takes blood for full blood count, urea and electrolytes, and clotting screen. Additional tests such as those for troponin levels, liver function, and C reactive protein can be added later, depending on the suspected diagnosis. Some emergency departments will have a “point of care” testing machine that can produce full blood count and blood gas results in minutes. The nurse administers the intravenous fluid through a cannula.
Whenever an intervention, such as intravenous fluids, is given, repeat assessment from A to E should be done to assess the effectiveness of the intervention—for example, blood pressure should be checked again.
The junior doctor checks Mr B’s pupils, consciousness level (using the alert, voice, pain, unresponsive scale or Glasgow coma scale), and capillary blood glucose level, which is commonly forgotten. Some doctors advocate remembering the phrase, “Don’t ever forget glucose” under the assessment of “D” to emphasise its importance.6
2310 hours: Mr B’s pupils are equal and reactive, glucose is 6.7 mmol/L, and his Glasgow coma scale score is 15 (fully awake).
None required at this point.
The junior doctor inspects Mr B’s body for any external signs that may explain the cause of his illness—for example, external haemorrhage, needle marks, bruises, and long bone deformities. In this case, he also looks closely for other areas of the body that may have been burnt. The nurse checks Mr B’s temperature as part of the exposure assessment.
2311 hours: Mr B’s temperature is 36.7°C and further examination shows partial thickness burns to his anterior chest. Surface burns are present on about 5% of the body.7
The junior doctor prescribes morphine as analgesia, which is administered by the nurse, who also covers the burns with burns dressings and cling film.
The team then reassess the patient and the effects of the medical interventions—that is, the team repeats the A-E assessment.
2320 hours: the emergency department registrar arrives in resus and reviews the case with the junior doctor and nurse.
2325 hours: the anaesthesia registrar and foundation doctor arrive in resus and begin to reassess Mr B’s airway. Suddenly, Mr B’s SpO2 drops to 89% on oxygen, and he starts to have stridor. The anaesthetists decide to intubate Mr B and share their plan with the team. The emergency department registrar assumes the role of team leader at this point and prepares the team for emergency intubation.
2330 hours: the anaesthesia registrar attempts to intubate Mr B. Despite several attempts, this is difficult because of his oedematous airway. A supraglottic device (i-Gel) is also used, but ventilation proves impossible, even with a bag valve mask. Mr B’s SpO2 drops to 85%. The emergency department registrar asks the nurse to fetch the surgical airway kit and position it by the anaesthetists.
2335 hours: Mr B’s heart rate is now 140 beats/min and the SpO2 has dropped to 80%. The team decides to move on to a surgical airway, and this is finally achieved. After a few ventilations, Mr B’s SpO2 increases to 97%.
0030 hours: Mr B is transferred to the intensive care unit.
The intensive care unit team continues to monitor Mr B and manage him with intravenous fluids, analgesia, and antibiotics to prevent wound infection. A nasogastric tube is inserted to make sure nutrition is maintained. The plastic surgery team and specialist nurses review Mr B’s wounds and provide appropriate dressings to ensure wound healing. Mr B remains intubated until his airway oedema resolves. The intensive care unit team start to liaise with the burns unit to take over Mr B’s care.
A. Anticipate and be aware of the situation. Think about what could go wrong and plan ahead. In the scenario above, the junior doctor realised that Mr B had signs of smoke inhalation injury and sought to involve the anaesthetists and the emergency department registrar early on. Similarly, the emergency department registrar (team leader) requested a surgical airway kit in anticipation of a difficult airway.
B. Brief the team. The team leader should regularly brief the team on what the plan is and keep others informed of what the rest of the team is doing.
C. Communicate clearly. Every member of the team should verbalise their concerns. Use closed loop communication to avoid any misunderstandings. In the scenario above, when the team leader asks the healthcare assistant to recannulate Mr B, the assistant should verbally acknowledge the request and state when it is done.
D. Delegate and distribute the workload. By delegating the role of recannulating Mr B, the team leader was able to maintain an overview of the management and let the anaesthetist focus on the task of intubation.
E. Know your environment and equipment. As a medical student, familiarise yourself with the resus environment before you start. In the scenario, the emergency department registrar and the nurse knew where the surgical airway kit was kept and knew how the ventilator worked, which made the process easier and safer.
Originally published as: Student BMJ 2016;24:i4512
Competing interests: None declared.
Provenance and peer review: Commissioned; externally peer reviewed.