Sedation for Echocardiography for Children with Congenital Heart Disease

Publication: 09/09/2013  --
Last review: 07/05/2018  
Next review: 07/05/2021  
Standard Operating Procedure
ID: 3422 
Approved By: Trust Clinical Guidelines Group 
Copyright© Leeds Teaching Hospitals NHS Trust 2018  


This Standard Operating Procedure is intended for use by healthcare professionals within Leeds unless otherwise stated.
For healthcare professionals in other trusts, please ensure that you consult relevant local and national guidance.

Sedation for Echocardiography for Children with Congenital Heart Disease

Background and indications for standard operating procedure/protocol

This guideline should be used for echocardiography that may cause the child distress; not every child requires sedation, and it should not be a substitute for adequate preparation and non-pharmacological interventions.

This guideline is based on the NICE clinical guideline 112, Sedation in Children and Young People, 20101 and current practice in Paediatric Cardiology.

The pharmacological interventions described in this guideline normally result in the patient being under a deep level of sedation.

NICE defines deep sedation as a drug-induced depression of consciousness during which patients are asleep, and cannot be easily roused, but do respond purposefully to repeated or painful stimulation.

Back to top

Procedure method (step by step)


Assess the patient’s suitability for sedation by reviewing:

  • Current medical and surgical conditions
  • Weight
  • Past medical history - including any previous problems with sedation/anaesthesia
  • Current medication and allergy status
  • Physical status - including airway
  • Psychological and developmental status

Ensure the patient has been clerked and that valid consent for pre-procedure sedation has been taken by medical staff (either in pre-assessment clinic or on the ward) and that this has been documented in the medical notes.

The patient should be fasted before sedation, applying the 2-4-6 rule:

  • 2 hours for clear fluids
  • 4 hours for breast milk
  • 6 hours for solids and formula milk

Before giving sedation, confirm and record the time of the last food and fluid intake in the nursing records.

Baseline observations should be documented pre-sedation. After sedation has been given, the patient should be monitored as follows:

  • Respiratory rate
  • Heart rate (continuous ECG monitoring)
  • Oxygen saturations
  • Blood pressure
  • Sedation score

Observations should be recorded at five minute intervals. The PAWS (Paediatric Advanced Warning Score) chart should be used.

NICE guidelines recommend monitoring end tidal CO2 (capnography) during deep sedation, but this is not current practice on the Paediatric Cardiology ward at LTH. This has been discussed at Clinical Governance June 2015 - to continue current practice.

When to seek advice senior medical advice (ST3 or above):

  1. concern about potential airway/breathing problem
  2. neonates
  3. contraindications to medication (see below)
  4. if the patient has any renal or hepatic impairment
  5. patients with arrhythmias


Trained staff should always supervise sedation. Two trained healthcare professionals should be present and there must be immediate access to resuscitation equipment. A saturation monitor should be attached when the patient is given the sedation and should remain in place until the patient is awake. If this is not possible, this should be documented in the patient’s medical notes, including the reason why.

Sedation should be given 20-30 minutes before planned echocardiography, with an appreciation that there is inter-patient variability in onset time. If adequate sedation has not been achieved 45 minutes after sedation has been given, consider a second half-dose after discussion with a Paediatric Cardiologist.





Stat Dose

Maximum Dose

<6 months

Chloral Hydrate




6 - 12 months

Chloral Hydrate




>1 year

Chloral Hydrate




Chloral hydrate is used prior to procedures to reduce anxiety and provide sedation. It is rapidly absorbed from the GI tract following oral or rectal administration, its active metabolite, trichloroethanol, has a plasma half life of 8-11 hours. The main side effects of chloral hydrate are gastric irritation, nausea, vomiting and flatulence. Contraindications to chloral hydrate are gastritis, acute porphyria and severe cardiac disease. However, it is routinely used in paediatric cardiology patients.

Alimemazine (trimeprazine) is a sedating antihistamine that is used as a premedication for procedures. The half-life of alimemazine is 5-8 hours. Side effects include headache, urinary retention, dry mouth, blurred vision and gastrointestinal disturbances. Alimemazine should only be given to children <2 years following specialist medical advice and should be used with caution in patients with epilepsy, urinary retention, glaucoma and pyloroduodenal obstruction.

Chloral hydrate comes as a 500mg/5mL oral solution and as 25mg, 100mg and 200mg suppositories and these are available as stock on the paediatric cardiology ward. The oral solution can be diluted in water or juice to mask the unpleasant taste and reduce gastric irritation.

Alimemazine comes as a 30mg/5mL oral solution and this is available as stock on the paediatric cardiology ward.

Before the patient is discharged, ensure all of the following criteria are met:

  • Vital signs have returned to pre-sedation levels, including:
    • heart rate
    • blood pressure
    • respiratory rate
    • body temperature
  • That the patient is fully awake and orientated (or returned to pre-sedation levels) and that there is no risk of further reduced levels of consciousness
  • Any nausea, vomiting or pain are adequately managed
  • That parents/carers have been warned that behavioural upsets are common
  • That parents/carers have received verbal and written guidance (“Advice for Parents Whose Child has had Sedation”) on the safe handling of their child
  • That at least one hour has passed since the child woke

Once the child is fully awake, eating and drinking can resume as normal.

It must be documented in the patient’s notes that all the criteria detailed above had been met before the patient is discharged.

Back to top


Record: 3422
Clinical condition:
Target patient group:
Target professional group(s): Secondary Care Doctors
Secondary Care Nurses
Adapted from:

Evidence base

  1. NICE guidelines, 2010. Sedation in Children and Young People, CG112. Available at [Accessed 01/06/2015] (Evidence Level A)
  2. BNF 2014-2015
  3. Martindale: The Complete Drug Reference, accessed via Medicines Complete on 01/06/2015
  4. AHFS Drug Information, accessed via Medicines Complete on 2/1/13
  5. Micromedex, accessed on 01/06/2015
  6. Medicines for Children 2003

Back to top

Approved By

Trust Clinical Guidelines Group

Document history

LHP version 1.0

Related information

Not supplied

Equity and Diversity

The Leeds Teaching Hospitals NHS Trust is committed to ensuring that the way that we provide services and the way we recruit and treat staff reflects individual needs, promotes equality and does not discriminate unfairly against any particular individual or group.