Prescribing basics

Benzodiazepine Overdose | Acute Management | ABCDE

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This guide provides an overview of the recognition and immediate management of benzodiazepine overdose using an ABCDE approach.

The ABCDE approach can be used to perform a systematic assessment of a critically unwell patient. It involves working through the following steps:

  • Airway
  • Breathing
  • Circulation
  • Disability
  • Exposure

Each stage of the ABCDE approach involves clinical assessment, investigations, interventions. Problems are addressed as they are identified and the patient is re-assessed regularly to monitor their response to treatment.

This guide has been created to assist students in preparing for emergency simulation sessions as part of their training, it is not intended to be relied upon for patient care.


General management in suspected overdose

Intentional overdose

It is important to remember that in the context of drug overdose it can be difficult to know the types and doses of drugs that have been consumed or injected (therefore mixed overdose should always be considered). In the context of intentional overdose, patients may not be forthcoming about what they have taken. Illicit drugs are often ‘cut’ (diluted) with other components, including those which produce a similar pharmacological effect but which are potentially more harmful (e.g. methanol in illicit alcohol).

Accidental overdose

Benzodiazepine overdose can also occur accidentally when patients combine them with other central nervous system depressants such as alcohol or opioids which potentiate the effect of benzodiazepines. As a result, careful counselling to inform patients of these risks is advised for all patients being treated with benzodiazepines.

Iatrogenic overdose

Benzodiazepine overdose can be iatrogenic as a result of erroneous prescribing or mistakes during the preparation or administration of a drug.


Clinical features

Benzodiazepines enhance the effect of the neurotransmitter gamma-aminobutyric acid (GABA) resulting in sedative, anxiolytic, anticonvulsant and muscle relaxant effects. These properties of benzodiazepines make them a particularly dangerous drug to take in overdose.

Clinical features of benzodiazepine overdose can include:

  • Reduced level of consciousness (including coma): if severe this can result in loss of airway tone and reflexes leading to hypoxia if left untreated.
  • Respiratory depression: decreased respiratory rate can result in hypoxia and inadequate tissue perfusion.
  • Hypotension
  • Bradycardia
  • Rhabdomyolysis
  • Hypothermia

It is important to consider the presence of dual pathology which may relate to the patient’s overdose:

  • Trauma secondary to falls (e.g. head injury)
  • Aspiration pneumonia secondary to a reduced level of conciousness

Tips before you begin

General tips for applying an ABCDE approach in an emergency setting include:

  • Treat all problems as you discover them.
  • Re-assess regularly and after every intervention to monitor a patient’s response to treatment.
  • Make use of the team around you by delegating tasks where appropriate.
  • All critically unwell patients should have continuous monitoring equipment attached for accurate observations.
  • Clearly communicate how often would you like the patient’s observations relayed to you by other staff members.
  • If you require senior input, call for help early using an appropriate SBARR handover structure.
  • Review results as they become available (e.g. laboratory investigations).
  • Make use of your local guidelines and algorithms in managing specific scenarios (e.g. acute asthma).
  • Any medications or fluids will need to be prescribed at the time (in some cases you may be able to delegate this to another member of staff).
  • Your assessment and management should be documented clearly in the notes, however, this should not delay initial clinical assessment, investigations and interventions.
  • TOXBASE (toxbase.org) provides detailed advice on a wide range of biochemical and pharmaceutical agents. In an acute situation, you should request a print out of the TOXBASE article for the drugs that you think the patient has been exposed to.

Initial steps

Acute scenarios typically begin with a brief handover from a member of the nursing staff including the patient’s nameagebackground and the reason the review has been requested.

You may be asked to review a patient with benzodiazepine overdose due to agitationbradypnoea and/or reduced level of consciousness.

Introduction

Introduce yourself to whoever has requested a review of the patient and listen carefully to their handover.

Interaction

Introduce yourself to the patient including your name and role.

Ask how the patient is feeling as this may provide some useful information about their current symptoms.

In the context of benzodiazepine overdose, this may not be possible due to impaired consciousness.

Preparation

Make sure the patient’s notesobservation chart and prescription chart are easily accessible.

Ask for another clinical member of staff to assist you if possible.

If the patient is unconscious or unresponsive, start the basic life support (BLS) algorithm as per resuscitation guidelines.


Airway

Benzodiazepines cause central nervous system depression which can result in loss of consciousness and loss of airway control.

Clinical assessment

Can the patient talk?

Yes: if the patient can talk, their airway is patent and you can move on to the assessment of breathing.

No:

  • Look for signs of airway compromise: these include cyanosis, see-saw breathing, use of accessory muscles, diminished breath sounds and added sounds.
  • Open the mouth and inspect: look for anything obstructing the airway such as secretions or a foreign object.

Interventions

Regardless of the underlying cause of airway obstruction, seek immediate expert support from an anaesthetist and the emergency medical team (often referred to as the ‘crash team’). In the meantime, you can perform some basic airway manoeuvres to help maintain the airway whilst awaiting senior input.

Head-tilt chin-lift manoeuvre

Open the patient’s airway using a head-tilt chin-lift manoeuvre:

1. Place one hand on the patient’s forehead and the other under the chin.

2. Tilt the forehead back whilst lifting the chin forwards to extend the neck.

3. Inspect the airway for obvious obstruction. If an obstruction is visible within the airway, use a finger sweep or suction to remove it.

Jaw thrust

If the patient is suspected to have suffered significant trauma with potential spinal involvement, perform a jaw-thrust rather than a head-tilt chin-lift manoeuvre:

1. Identify the angle of the mandible.

2. With your index and other fingers placed behind the angle of the mandible, apply steady upwards and forward pressure to lift the mandible.

3. Using your thumbs, slightly open the mouth by downward displacement of the chin.

Oropharyngeal airway (Guedel)

Airway adjuncts are often helpful and in some cases essential to maintain a patient’s airway. They should be used in conjunction with the maneuvres mentioned above as the position of the head and neck need to be maintained to keep the airway aligned.

An oropharyngeal airway is a curved plastic tube with a flange on one end that sits between the tongue and hard palate to relieve soft palate obstruction. It should only be inserted in unconscious patients as it is otherwise poorly tolerated and may induce gagging and aspiration.

To insert an oropharyngeal airway:

1. Open the patient’s mouth to ensure there is no foreign material that may be pushed into the larynx. If foreign material is present, attempt removal using suction.

2. Insert the oropharyngeal airway in the upside-down position until you reach the junction of the hard and soft palate, at which point you should rotate it 180°. The reason for inserting the airway upside down initially is to reduce the risk of pushing the tongue backwards and worsening airway obstruction.

3. Advance the airway until it lies within the pharynx.

4. Maintain head-tilt chin-lift or jaw thrust and assess the patency of the patient’s airway by looking, listening and feeling for signs of breathing.

Nasopharyngeal airway (NPA)

A nasopharyngeal airway is a soft plastic tube with a bevel at one end and a flange at the other. NPAs are typically better tolerated in patients who are partly or fully conscious compared to oropharyngeal airways. NPAs should not be used in patients who may have sustained a skull base fracture, due to the small but life-threatening risk of entering the cranial vault with the NPA.

To insert a nasopharyngeal airway:

1. Check the patency of the patient’s right nostril and if required (depending on the model of NPA) insert a safety pin through the flange of the NPA.

2. Lubricate the NPA.

3. Insert the airway bevel-end first, vertically along the floor of the nose with a slight twisting action.

4. If any obstruction is encountered, remove the tube and try the left nostril.

Other interventions

If the patient has clinical signs of anaphylaxis (e.g. angioedema, rash) commence appropriate treatment as discussed in our anaphylaxis guide.

CPR

If the patient loses consciousness and there are no signs of life on assessment, put out a crash call and commence CPR.

Re-assessment

Make sure to re-assess the patient after any intervention.


Breathing

Respiratory depression is a common feature of benzodiazepine overdose.

Clinical assessment

Observations

Review the patient’s respiratory rate:

  • normal respiratory rate is between 12-20 breaths per minute.
  • Bradypnoea is a common clinical feature of benzodiazepine overdose.

Review the patient’s oxygen saturation (SpO2):

  • normal SpOrange is 94-98% in healthy individuals and 88-92% in patients with COPD who are at high-risk of COretention.
  • Hypoxaemia may occur in benzodiazepine overdose due to respiratory depression.

See our guide to performing observations/vital signs for more details.

Inspection

Inspect the patient from the end of the bed:

  • Cyanosis: bluish discolouration of the skin due to poor circulation or inadequate oxygenation of the blood.

Auscultation

Auscultate the chest to screen for evidence of other respiratory pathology (e.g. coarse crackles may be present if the patient has developed aspiration pneumonia).

Investigations and procedures

Arterial blood gas

Take an ABG if indicated (e.g. low SpO2) to quantify the degree of hypoxia.

Patients with benzodiazepine overdose are at risk of developing type 2 respiratory failure (i.e. low SpOand raised  CO2) due to respiratory depression.

Chest X-ray

A chest X-ray may be indicated if abnormalities are noted on auscultation (e.g. reduced air entry, coarse crackles) to screen for evidence of aspiration pneumonia. A chest X-ray should not delay the emergency management of opioid overdose.

See our CXR interpretation guide for more details.

Interventions

Oxygen

Administer oxygen to all critically unwell patients during your initial assessment. This typically involves the use of a non-rebreathe mask with an oxygen flow rate of 15L. If the patient has COPD and a history of COretention you should switch to a venturi mask as soon as possible and titrate oxygen appropriately.

If the patient is conscious, sit them upright as this can also help with oxygenation.

CPR

If the patient loses consciousness and there are no signs of life on assessment, put out a crash call and commence CPR.

Re-assessment

Make sure to re-assess the patient after any intervention.


Circulation

Bradycardia and hypotension are common features of benzodiazepine overdose. Cardiac arrhythmias may also be seen.

Clinical assessment

Blood pressure

Hypotension is also a common clinical feature of benzodiazepine overdose.

Capillary refill time

Capillary refill time may be prolonged in the context of benzodiazepine overdose.

Fluid balance assessment

Calculate the patient’s fluid balance:

  • Calculate the patient’s current fluid balance using their fluid balance chart (e.g. oral fluids, intravenous fluids, urine output, drain output, stool output, vomiting) to inform resuscitation efforts.
  • Reduced urine output (oliguria) is typically defined as less than 0.5ml/kg/hour in an adult.

Investigations and procedures

Intravenous cannulation

Insert at least one wide-bore intravenous cannula (14G or 16G) and take blood tests as discussed below.

See our intravenous cannulation guide for more details.

Blood tests

Collect blood tests after cannulating the patient including:

  • FBC: to screen for anaemia and signs of infection.
  • U&Es: to assess renal function (impaired renal function increases cerebral sensitivity to benzodiazepines).
  • CK: benzodiazepine overdose can cause rhabdomyolysis.
  • CRP: to screen for evidence of infection.
  • Lactate: to screen for evidence of reduced end-organ perfusion.
  • Coagulation studies: to screen for coagulopathy.
  • Toxicology screen: to screen for other drugs which may have been taken as part of a mixed overdose (e.g. opiates).

ECG

Record a 12-lead ECG to screen for arrhythmias which may develop in the context of benzodiazepine overdose.

Attach 3-lead continuous ECG monitoring if available.

See our guides to recording and interpreting an ECG for more details.

Interventions

Intravenous fluids

Patients who have overdosed on benzodiazepines may be hypotensive.

Hypotensive patients require fluid resuscitation:

  • Administer a 500ml bolus Hartmann’s solution or 0.9% sodium chloride (warmed if available) over 15 mins.
  • Administer 250ml boluses in patients at increased risk of fluid overload (e.g. heart failure).

After each fluid bolus, reassess for clinical evidence of fluid overload (e.g. auscultation of the lungs, assessment of JVP).

Repeat administration of fluid boluses up to four times (e.g. 2000ml or 1000ml in patients at increased risk of fluid overload), reassessing the patient each time.

Seek senior input if the patient has a negative response (e.g. increased chest crackles) or if the patient isn’t responding adequately to repeated boluses (i.e. persistent hypotension) as they may require vasopressors +/- inotropes.

See our fluid prescribing guide for more details on resuscitation fluids.

CPR

If the patient loses consciousness and there are no signs of life on assessment, put out a crash call and commence CPR.

Re-assessment

Make sure to re-assess the patient after any intervention.


Disability

Clinical assessment

Consciousness

In the context of benzodiazepine overdose, a patient’s consciousness level may be reduced.

Assess the patient’s level of consciousness using the AVPU scale:

  • Alert: the patient is fully alert, although not necessarily orientated.
  • Verbal: the patient makes some kind of response when you talk to them (e.g. words, grunt).
  • Pain: the patient responds to a painful stimulus (e.g. supraorbital pressure).
  • Unresponsive: the patient does not show evidence of any eye, voice or motor responses to pain.

If a more detailed assessment of the patient’s level of consciousness is required, use the Glasgow Coma Scale (GCS).

Pupils

Assess the patient’s pupils:

  • Inspect the size and symmetry of the patient’s pupils: dilated pupils are associated with benzodiazepine overdose. The presence of pinpoint pupils may suggest opioid overdose.

Drug chart review

Review the patient’s drug chart for medications which may cause neurological abnormalities (e.g. opioids, benzodiazepines).

Investigations

Blood glucose and ketones

Measure the patient’s capillary blood glucose level to screen for causes of a reduced level of consciousness (e.g. hypoglycaemia or hyperglycaemia). The normal reference range for capillary blood glucose is 4.0-11.0 mmol/L.

A blood glucose level may already be available from earlier investigations (e.g. ABG, venepuncture).

If the blood glucose is elevated, check ketone levels which if also elevated may suggest a diagnosis of diabetic ketoacidosis (DKA).

See our blood glucose measurement, hypoglycaemia and diabetic ketoacidosis guides for more details.

Imaging

Request a CT head if intracranial pathology is suspected after discussion with a senior.

See our guide on interpreting a CT head for more details.

Interventions

Maintain the airway

Alert a senior immediately if you have any concerns about the consciousness level of a patient. A GCS of 8 or below warrants urgent expert help from an anaesthetist. In the meantime, you should re-assess and maintain the patient’s airway as explained in the airway section of this guide.

Flumazenil

Flumazenil is a GABA receptor antagonist, allowing it to directly reverse the central nervous system (CNS) and subsequent respiratory depression caused by benzodiazepines. 

Flumazenil should only be used when:

  • CNS depression is severe enough that patients are requiring ventilation
  • You are confident that only benzodiazepines have been taken (e.g. no possibility of a mixed overdose)
  • The patient is not known to be benzodiazepine dependent

Use outside of these conditions risks precipitating seizures (e.g. if a patient has also taken tricyclic antidepressants) which are particularly difficult to treat due to the GABA antagonism caused by Flumazenil.

Only enough flumazenil to reverse the respiratory depression should be administered to reduce the risk of side effects. Doses can be located on TOXBASE or in the BNF.

CPR

If the patient loses consciousness and there are no signs of life on assessment, put out a crash call and commence CPR.

Re-assessment

Make sure to re-assess the patient after any intervention.


Exposure

It may be necessary to expose the patient during your assessment: remember to prioritise patient dignity and conservation of body heat. 

Clinical assessment

Inspection

Inspect the patient for evidence of injection sites, injuries or infection.

Review the output of the patient’s catheter and any surgical drains.

Temperature

Measure the patient’s temperature:

  • Benzodiazepine overdose is typically associated with hypothermia
  • Amphetamine overdose is typically associated with hyperthermia

Interventions

Warming

Consider warming (e.g. Bair Hugger™) in hypothermia (seek senior input).

Catheterisation

Catheterise the patient to closely monitor urine output to guide fluid resuscitation and need for escalation.

CPR

If the patient loses consciousness and there are no signs of life on assessment, put out a crash call and commence CPR.

Re-assessment

Make sure to re-assess the patient after any intervention.


Reassess ABCDE

Re-assess the patient using the ABCDE approach to identify any changes in their clinical condition and assess the effectiveness of your previous interventions.

Deterioration should be recognised quickly and acted upon immediately.

Seek senior help if the patient shows no signs of improvement or if you have any concerns.

Support

You should have another member of the clinical team aiding you in your ABCDE assessment, such a nurse, who can perform observations, take samples to the lab and catheterise if appropriate.

You may need further help or advice from a senior staff member and you should not delay seeking help if you have concerns about your patient.

Use an effective SBARR handover to communicate the key information effectively to other medical staff.


Next steps

Well done, you’ve now stabilised the patient and they’re doing much better. There are just a few more things to do…

Take a history

Revisit history taking to explore relevant medical history. If the patient is confused you might be able to get a collateral history from staff or family members as appropriate.

See our history taking guides for more details.

Review

Review the patient’s notescharts and recent investigation results.

Review the patient’s current medications and check any regular medications are prescribed appropriately.

Document

Clearly document your ABCDE assessment, including history, examination, observations, investigations, interventions, and the patient’s response.

See our documentation guides for more details.

Discuss

Discuss the patient’s current clinical condition with a senior clinician using an SBARR style handover.

Questions which may need to be considered include:

  • Are any further assessments or interventions required?
  • Does the patient need a referral to HDU/ICU?
  • Does the patient need reviewing by a specialist?
  • Should any changes be made to the current management of their underlying condition(s)?

Handover

The next team of doctors on shift should be made aware of any patient in their department who has recently deteriorated.


References

  1. Generic core material: prehospital emergency care course/core material. Editorial leads: Andrew Thurgood, Darren Walter. Clinical review team: Andrew Thurgood [et al.]. Contributors, Adrian Noon [et al.]
  2. TOXBASE: Diazepam. Available from: [LINK].
  3. BNF. Flumazenil. Available from: [LINK].

 

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