Titrating Sedation in Mechanically Ventilated Patients by using aRASS score ( maintaining or weaning ventilation ) on Adult Critical Care ( Cardiac and Neuro patients exempted ) - Standard Operating Procedure ( SOP ) for

Publication: 03/10/2016  
Next review: 05/10/2025  
Standard Operating Procedure
ID: 4747 
Approved By: Trust Clinical Guidelines Group 
Copyright© Leeds Teaching Hospitals NHS Trust 2022  


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.

Standard Operating Procedure (SOP) for Titrating Sedation in Mechanically Ventilated Patients by using aRASS score (maintaining or weaning ventilation) on Adult Critical Care (Cardiac and Neuro patients exempted)

Background and indications

Sedation and analgesia are used to facilitate life support treatment whilst relieving any distress.

Excess sedation leads to prolonged length of stay and more morbidity.

Inadequate sedation leads to poor supportive treatment and pain.

Use of a specific assessment tool such as aRASS aids the titration of medication to achieve patient safety but does not hinder waking and weaning plans to aid recovery.

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Procedure method (step by step)

A reminder message about using aRASS will be said during both the medical and nursing huddles and handovers at the start of each shift.

All patients started on sedation (propofol and/or Alfentanil) in Adult Critical Care (ACC) will have a target adapted Richmond Agitation Sedation Score (aRASS) completed on commencement of sedation and then twice a day by a prescriber.

Patients will be assessed as being in one of 3 phases of recovery.
The phases are:-

See chart below for details of types of ventilator support associated with each phase.

This assessment contributes to the setting of infusion rates to either maintain or reduce sedation to aid waking and weaning from a ventilator.

When setting the targets consider planned procedures during the day, sedation holds and potential extubation.

The target aRASS score is determined following a clinical assessment and set by a medical or non-medical identified prescriber.
Adjustments to sedation infusion rates are made with aim of achieving the set aRASS target.
It may be necessary to commence adjunct treatment early to promote progression to the GREEN phase.

Challenges in achieving target aRASS will be dealt with as per flow charts RED, AMBERand GREEN. See appendix’s 1,2 and 3.
If the target aRASS is not able to be maintained or achieved and the patient needs additional treatments then any aRASS changes should be agreed between the clinical team. The decision should be noted in the records.

Patients in the Stable/ Recovery (AMBER) phase are to have an anticipatory plan for potential sedation hold for the next day.

Patients in the Weaning (GREEN) phase green group with a possibility of sedation hold and extubation trial will be highlighted in the morning handover.
Sedation holds will be planned events post daily medical review.

Set or adjust the ventilator mode to enable patients to self-ventilate at the earliest opportunity.

Ventilator Support associated with Phase of Recovery.


Target RASS range

Patient status

Ventilator setting

Resuscitation and stabilisation phase

-5 to -3

High Respiratory support
CVS instability
Anticipated procedure in next 6 hrs
High ICP or neurological Cause

Mandatory Mode
Automode PC
Automode PRVC

Stable and Recovery phase

-2 to -1

Stable and decreasing Respiratory support
Stable and decreasing CVS support
Anticipated sedation Hold in the next 24 hrs

Spontaneous mode
Automode PS

If stable reduce PS gradually

Weaning phase


Planned sedation Hold
If in pain for Analgesics – not to increase propofol
If agitated for anti-delirium drugs

Spontaneous mode with minimal support

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Record: 4747
  • To achieve optimal sedation in mechanically ventilated patients.
  • To promote progression to self-ventilation and avoid resedation events due to agitation (delirium). 
    This SOP links to the SOP for Management of Delirium.
  • The titration of drugs must be aimed at achieving objective targets set for treatments and adjusting for objective scores for patient comfort.
Clinical condition:
Target patient group:
Target professional group(s): Secondary Care Doctors
Secondary Care Nurses
Registered Nurses Working in Critical Care
Adapted from:

Evidence base

Not supplied

Approved By

Trust Clinical Guidelines Group

Document history

LHP version 1.0

Related information

Appendix 1 - Red flowchart

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Appendix 2 - Amber aRASS flowchart

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Appendix 3 - Green flowchart

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Appendix 4 - Bedside SOP for aRASS and sedation

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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.