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Diagnostic sleep study service

This page has information for clinicians who want to refer for diagnostic investigations at the children's sleep service at Evelina London.


External Referrals

External referrals for diagnostic investigations should be made by referral letter stating the background history and investigation required. For queries, emails should be sent to gst-tr.PaediatricSleepSecretaries@nhs.net

Requests may be redirected to other paediatric centres offering diagnostic investigations if referral to those centres is more appropriate.

We do not routinely offer oximetry as a diagnostic service to external referrers.

In some cases, referral for diagnostic investigation only may not be appropriate and outpatient assessment may be more suitable. We will discuss this with referring clinicians.

Our sleep service referral checklist (PDF 1.29Mb) helps us decide if we can accept a patient for referral, fast track if necessary, and move into the most appropriate investigation and management pathway as early as possible.

Internal Referrals

Clinicians within Evelina London can request these directly via EPR (type “sleep” into the order request box and scroll down – the paediatric options are towards the bottom of the list).


Available diagnostic investigations: elective

The department offers a number of different diagnostic investigations. 

Elective studies are booked 6-8 weeks in advance, and are intended to be carried out when children are generally well/at their normal baseline. It is usually not appropriate to carry out an elective sleep study when the child is unwell, and studies may be postponed if a child is unwell at the time of their planned study. 


Diagnostic investigations

Paediatric home oximetry study

This is a limited respiratory sleep study which measures only oxygen saturation and heart rate. It is usually carried out over two nights at home.

Oximetry can be requested by any Evelina London clinician with EPR diagnostic requesting rights, and does not require specific discussion with the sleep team.

This is not a diagnostic test for obstructive sleep apnoea/sleep disordered breathing.

In the context of a clinical diagnosis of OSA/sleep disordered breathing, oximetry can be used as part of overall clinical assessment to assess severity to allow stratification of intervention urgency, and need for peri-operative support. Oximetry can also be used as part of overall respiratory assessment of a patient.

Paediatric cardiorespiratory sleep study

An overnight cardiorespiratory sleep study primarily to assess for obstructive sleep apnoea/sleep disordered breathing. These studies can be carried out in the Children’s Sleep Centre or in the patient’s home.

Cardiorespiratory sleep study can be requested by any Evelina London clinician with EPR diagnostic requesting rights, and does not require specific discussion with the sleep team.

For most patients where obstructive sleep apnoea/sleep disordered breathing is the principal concern, and where oximetry alone is not sufficient, this is an appropriate formal sleep study to request.

Home cardiorespiratory studies

We have a limited capacity to carry out some cardiorespiratory studies as home studies.

These provide slightly less detailed information than an inpatient study, but are able to appropriately diagnose sleep disordered breathing – the differences in study parameters are summarised below.

Study parameterIn-patientHome

Heart rate



Oxygen saturation



Carbon dioxide clearance






Thoracic/abdominal movements












Limb movements



Decision as to whether a study will be carried out in-hospital or at home is made by the sleep study booking team; to utilise our resources efficiently we may not be able to offer families a choice. Please do not promise families these studies will be carried out in a specific location unless you have confirmed this in advance with us. Patients with good clinical reasons for studies to take place in a specific location will be considered – please enter the reason for this on the EPR request. 

Paediatric actigraphy study

A specialised investigation used to assess total sleep time and sleep pattern in the home environment.

It can only be requested following discussion with a paediatric sleep consultant (either Dr Farquhar or Professor Gringras).

Waiting time for this investigation is usually four to six weeks.

Paediatric polysomnography (PSG)

This is a specialised inpatient overnight sleep study and is the 'gold standard' level of sleep study. These studies are usually carried out in the Children’s Sleep Centre.

In addition to parameters measured in a cardiorespiratory sleep study, PSG also includes limited EEG montage which allows identification of sleep stages and a more comprehensive assessment of sleep quality to be made.

PSG can only be requested following discussion with a paediatric sleep consultant. 

Video Telemetry

As PSG uses a limited EEG montage, it is not an investigation for assessment of possible nocturnal seizures. For this combined PSG and video EEG telemetry needs to be requested via the EEG department, not the sleep service. 

This can be requested (by Evelina London clinicians) via the EEG video telemetry EPR request form by ticking the combined sleep study option.

Paediatric polysomnography with multiple sleep latency test

This is a highly specialised inpatient investigation which in addition to overnight PSG assesses daytime sleepiness.

It is principally a diagnostic test for narcolepsy, though can have other uses.

PSG with MSLT can only be requested following discussion with a paediatric sleep consultant.

Available diagnostic investigations: acute

We have very limited capacity to carry out urgent/acute sleep studies. 

All requests for an urgent sleep study must all be discussed with either a sleep consultant and/or the respiratory consultant on service.

Senior members of the paediatric sleep team are always happy to discuss patients and offer advice as to how the most appropriate diagnostic information for patients can be achieved as quickly as possible.

Cancellation slots

Where urgent studies are requested for out-patients, we are able to offer short-notice cancellation slots to families if these become available before their electively booked study date. Please indicate if families are happy to be offered appointments at short-notice on the request form, and include best contact details for them. Cancellation slots cannot be guaranteed.

If assessment is needed more urgently than this, then children would normally need to be admitted to Evelina London by their consultant, and options for assessment discussed with the sleep/respiratory teams. 

Available diagnostic investigations: acute

Paediatric inpatient O/ CO2 study

This is an inpatient overnight limited respiratory and measures only oxygen saturation, carbon dioxide level and heart rate.

These studies are predominantly carried out on Snow Leopard Ward, but can be carried out elsewhere in the hospital.

These studies must be discussed with a respiratory consultant before being requested – prioritisation and review of studies is usually carried out by the consultant on service for paediatric respiratory medicine. 

Paediatric urgent cardiorespiratory sleep study

We have capacity to do one urgent study per week; this is usually overnight on a Tuesday.

Determination of priority for urgent sleep study sits with the respiratory consultant on service and, if there are multiple patients needing urgent studies, prioritisation will be decided by them. 


Senior sleep team

If you have any queries in relation to diagnostic sleep studies, please discuss with a senior member of the team.

These are:

  • Professor Paul Gringras (head of department, consultant in sleep medicine)
  • Jane Orgill (chief sleep physiologist)
  • Dr Desaline Joseph (consultant in sleep medicine)
  • Kiran van den Eshof (deputy chief sleep physiologist)
  • Dr Michael Farquhar (consultant in sleep medicine)

Please contact by email in the first instance: PaediatricSleepSeniorTeam@gstt.nhs.uk

Alternatively you can call the Children’s Sleep Centre directly on 53287. 

Other useful information



We are based primarily in the Children’s Sleep Centre, on the 1st and 2nd floors of D Block, South Wing, St Thomas’ Hospital. A small number of studies are currently carried out in the sleep beds on Savannah Ward; we aim transition the majority of these studies to the Children’s Sleep Centre in 2019/2020.

The Sleep Centre is a dedicated five bedroom unit which is only used for sleep studies. It is staffed overnight by specialist paediatric sleep physiologists.


Patients and families are asked to attend the Sleep Centre for 5pm, and to leave by 7.30am the following morning.

On admission, patients are briefly reviewed by a member of the medical team.

Care by parent

For children to have studies in the Sleep Centre, a parent/carer must be resident with their child for the night. The parent/carer must carry out all routine care, including medical treatment/administration of medications, which the child would usually have at home overnight.

At present, if children have complex medical needs, have significant manual handling needs (eg hoisting) or parents are not able to do normal routine care for their child overnight, the sleep study will be carried out in the one of the two dedicated inpatient sleep study beds on Savannah Ward in Evelina London. Please note that a parent is still required to be resident with their child for the study. 

Final decision regarding the most appropriate location for any study to be carried out will be made by the sleep team.


All studies are reviewed within 24 hours by a physiologist and sleep consultant. Immediately abnormal results are prioritised and notified to the requesting clinician if appropriate.

Detailed analysis is then carried out by sleep physiologists and commented on by one of the paediatric sleep consultants; inpatient O2 / CO2 studies are usually reviewed by the on-call respiratory consultant.

Urgent or significantly abnormal studies are prioritised.

Requesting clinicians are notified by email when completed study results are uploaded to EPR. External clinicians are sent results by letter.

In the case of urgent or significantly abnormal results, the patient’s responsible referring consultant will also be directly contacted by a sleep consultant.

Clinical responsibility for reviewing the investigation result and correlating with the child's clinical status remains with the referring clinical team. We are always happy to provide input into interpreting a result where this is helpful.

Due to the complexity of inpatient sleep studies, there may be a delay of four to six weeks from the study date until a report is available (for non-urgent studies or studies which are not significantly abnormal). 

Oximetry results are usually available less than a week from the date the study is returned to the Children's Sleep Centre.

Sleep study results are not directly communicated to families, as appropriate interpretation of results is only possible in the overall clinical context of the child’s care. Results are expected to then be communicated to families by the referring clinician.



Outpatient appointment enquiries

Tel: 020 7188 4000


General enquiries (not relating to outpatient appointments)

Tel: 020 7188 4649
Email: gst-tr.PaediatricSleep

Monday-Friday, 9am-5pm

Sleep studies (enquiries relating to appointments for diagnostic sleep studies which have been already discussed)

Tel: 020 7188 3427

Monday-Friday, 8am-4pm

For clinic referral contacts, please see our referrals page.
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