This guide presents an overview of recognition and immediate management of benzodiazepine overdose using an ABCDE approach. The ABCDE approach can be utilized to conduct a systematic assessment of a critically unwell patient which involves working through these steps:
At each stage of the ABCDE approach, clinical assessment, investigations, and interventions must be done. Problems are addressed immediately and the patient is constantly monitored to observe the response to treatment.
This guide has been created to help students in preparing for emergency simulation sessions as part of their training and should not be utilized for patient care.
In the context of drug overdose, it is difficult to know the types and doses of drugs that have been taken or injected, so mixed overdose should be taken into account. Intentional overdose patients may not be open about what they have taken. Drugs are regularly cut (diluted) with other components, including those that produce a similar pharmacological effect but with higher risks (e.g. methanol in illicit alcohol).
Benzodiazepine overdose can also occur accidentally when combined with other central nervous system depressants like alcohol and opioids which amplify the effects of benzodiazepines. In light of this, careful counseling should be given to patients being given benzodiazepines to inform them of risks.
Benzodiazepine overdose can be caused by incorrect prescribing or mistakes in drug administration.
Benzodiazepines heighten the action of the neurotransmitter gamma-aminobutyric acid (GABA) which results in sedative, anxiolytic, anticonvulsant, and muscle relaxant effects. Thus, benzodiazepines are especially hazardous if taken in overdose.
Clinical features of benzodiazepine overdose are:
Dual pathology may also be present relating to the patient's overdose such as trauma due to falls.
Recognizing when the ABCDE approach should be utilized in an emergency setting is important for delivering effective treatment. This approach is used to assess critically unwell patients and features the following key elements: Airway, Breathing, Circulation along with Disability and Exposure.
When applying the ABCDE approach in an emergency setting, keep the following tips in mind:
Acute scenarios typically begin with a brief handover from a member of the nursing staff including the patient's name, age, background and the reason the review has been requested. You may be asked to review a patient with benzodiazepine overdose due to agitation, bradypnoea and/or reduced level of consciousness.
Introduce yourself to whoever has requested a review of the patient and listen carefully to their handover. Also 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.
Make sure the patient's notes, observation 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.
Benzodiazepines can cause central nervous system depression, resulting in loss of consciousness and airway control.
Yes: If the patient can talk, their airway is clear and you can assess breathing.
No:
No matter the cause of airway obstruction, seek immediate expert support from an anaesthetist and the emergency medical team. In the meantime, some basic airway maneuvers can help buy time while awaiting senior help.
Open the patient's airway with a head-tilt chin-lift manoeuvre:
1. Put one hand on the patient's forehead and the other under the chin.
2. Tilt the forehead back while lifting chin forward to extend the neck.
3. Inspect the airway for visible obstruction. If it is, use a finger sweep or suction to remove it.
If the patient may have spinal trauma, do a jaw-thrust instead of a head-tilt chin-lift manoeuvre:
1. Identify the angle of the mandible.
2. With index and other fingers behind the angle of the mandible, apply steady up and forward pressure to lift the mandible.
3. With thumbs, slightly open the mouth by pushing the chin down.
Airway adjuncts can be helpful in keeping the airway clear and should be used alongside the maneuvers mentioned above to keep the airway aligned. An oropharyngeal airway is a curved plastic tube with a flange at 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 can otherwise be poorly tolerated and can cause gagging and aspiration.
To insert an oropharyngeal airway:
1. Open the patient's mouth and check for foreign material that could be pushed into the larynx. If present, try to remove it with suction.
2. Insert the oropharyngeal airway upside-down until reaching the junction of the hard and soft palate, then rotate 180°.
3. Advance the airway into the pharynx.
4. Maintain head-tilt chin-lift or jaw thrust and check patency of the airway by looking, listening, and feeling for signs of breathing.
A nasopharyngeal airway is a soft plastic tube with a bevel at one end and a flange at the other. NPAs are usually better tolerated in patients who are conscious compared to oropharyngeal airways. NPAs should not be used in patients who could have sustained a skull base fracture due to the small but serious risk of entering the cranial vault with the NPA.
To insert a nasopharyngeal airway:
1.
Respiratory depression is a common feature of benzodiazepine overdose.
Review the patient's respiratory rate:
Review the patient's oxygen saturation (SpO2):
Inspect the patient from the end of the bed:
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).
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 SpO2 and raised CO2) due to respiratory depression.
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.
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 CO2 retention 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.
If the patient loses consciousness and there are no signs of life on assessment, put out a crash call and commence CPR.
Always re-assess the patient after any intervention.
Bradycardia, hypotension, and cardiac arrhythmias are all common features of benzodiazepine overdose.
Hypotension is a common clinical feature of benzodiazepine overdose.
Capillary refill time may be prolonged in the context of benzodiazepine overdose.
Calculate the patient's fluid balance:
Insert at least one wide-bore intravenous cannula (14G or 16G) and take blood tests as discussed below.
Collect blood tests after cannulating the patient including:
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.
Patients who have overdosed on benzodiazepines may be hypotensive. Hypotensive patients require fluid resuscitation:
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.
If the patient loses consciousness and there are no signs of life on assessment, put out a crash call and commence CPR.
Always re-assess the patient after any intervention.
When assessing a patient for benzodiazepine overdose, it is important to assess their level of consciousness. To do this, providers can use the AVPU scale: Alert, Verbal, Pain, Unresponsive. If more detail is required, the Glasgow Coma Scale (GCS) can be used.
As part of the assessment, providers should inspect the size and symmetry of the patient's pupils. Dilated pupils may indicate benzodiazepine overdose, while pinpoint pupils may suggest opioid overdose.
Reviewing the patient's drug chart for medications which may cause neurological abnormalities (e.g. opioids, benzodiazepines) can provide useful information.
Measuring capillary blood glucose can help to identify possible causes of a reduced level of consciousness, such as hypoglycaemia or hyperglycaemia. Checking ketone levels may point to a diagnosis of diabetic ketoacidosis (DKA), if the blood glucose is elevated.
The normal reference range for fasting plasma glucose is 4.0 - 5.8 mmol/l. Hypoglycaemia is defined as plasma glucose of less than 3.0 mmol/l and in-hospital patients with a blood glucose of ≤4.0 mmol/L should be treated if they are symptomatic.
If intracranial pathology is suspected, then a CT head should be requested after discussion with a senior.
If the patient's consciousness level causes concern, a senior should be alerted immediately. A GCS of 8 or below requires urgent help from an anaesthetist. Providers should re-assess and maintain the patient's airway during this time.
Flumazenil is a GABA receptor antagonist which is used to reverse the central nervous system and respiratory depression caused by benzodiazepines.
It should only be used where the CNS depression is severe enough to require ventilation, the patient has only taken benzodiazepines, and they are not known to be benzodiazepine dependent. Incorrect use could precipitate seizures due to the GABA antagonism.
Only administer enough flumazenil to reverse the respiratory depression to reduce the risk of side effects. Doses can be found on TOXBASE or the BNF.
If the patient loses consciousness and there are no signs of life on assessment, put out a crash call and commence CPR.
Remember to re-assess the patient after any intervention.
It may be necessary to expose the patient during your assessment. Prioritise patient dignity and conservation of body heat.
Inspect the patient for evidence of injection sites, injuries or infection. Also, review the output of the patient's catheter and any surgical drains.
Measure the patient's temperature. Benzodiazepine overdose is typically associated with hypothermia, whereas amphetamine overdose is typically associated with hyperthermia.
Consider warming (e.g. Bair Hugger™) with cases of hypothermia (consult senior input).
Catheterise the patient to closely monitor urine output to guide fluid resuscitation and need for escalation.
If the patient loses consciousness and there are no signs of life on assessment, put out a crash call and commence CPR.
Re-assess the patient using the ABCDE approach to identify any changes in their clinical condition and assess the effectiveness of your previous interventions. Recognise deterioration quickly and act upon it immediately. Seek senior advice if the patient shows no signs of improvement or if you have any worries. Have another member of the clinical team aid you in your ABCDE assessment, and use an effective SBARR handover to communicate key information effectively to other medical staff.
Once you have stabilised the patient, take a history to explore relevant medical history. If the patient is confused, you might be able to get a collateral history from staff or family members. Review the patient's notes, charts and recent investigation results. Check regular medications are prescribed appropriately. Clearly document your ABCDE assessment, including history, examination, observations, investigations, interventions and the patient's response.
To ensure accurate communication of information, it is important to utilize appropriate documentation guides when discussing patient care.
Discuss the patient's clinical condition with a senior clinician using an SBARR style handover. Questions which may need to be asked include:
The following shift of doctors should be made aware of any patient who has recently deteriorated.
