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I09 Postural Asphyxia

1. Security protective marking

1.1 Not protectively marked.

2. Summary of changes to policy

2.1 The following changes were made to this policy on 27 June 2013:

    • Additional point added to 5.1 relating to the responsibility of the safety officer.

2.2 This policy is due for review in June 2016.


3. Introduction

3.1. Postural Asphyxia occurs when a person is placed in a posture that prevents or impedes breathing. If the person cannot move from the position, death can occur very rapidly. Postural Asphyxia can occur in any position that restricts individuals' normal breathing mechanism.


3.2. Underlying circumstances in which this can occur are when:

      • A person is laid face down in a prone position and pressure is applied to the back;
      • A person is handcuffed and left lying in a prone position;
        (It should also be noted that in these circumstances, if left in a prone position, even without weight being placed on the back, the persons own body weight can restrict breathing and cause death. Particular care must be exercised in relation to the transportation of persons who are handcuffed in this way)
      • Positional asphyxia is not limited to restraint in a face down position. Restraining a person in a seated position may also reduce the ability to breathe, if the person is pushed forwards with the chest on or close to the knees. The risk will be higher in cases where the restrained person has a high Body Mass Index (BMI) and/or a large waist;
      • Any position during restraint that would provide a restriction to the normal mechanical process of breathing.

3.3. The risk is heightened under the following circumstances:

      • The person is intoxicated with alcohol or drugs, or has a known history of substance abuse, particularly cocaine;
      • The person has recently been engaged in violent activity (such as fighting with police) and is suffering respiratory muscle fatigue;
      • The person is substantially over-weight;
      • There is some form of obstruction to or blockage of the airway;
      • The person is unconscious for whatever other reason.
        Note:  A heightened level of stress in the individual will result in an increased chance of death when the subject is restrained.

4. Warning signs

      • Gurgling/gasping sounds/foam or mucus coming from the nose or mouth and any other visual signs that the person is struggling to breathe;
      • Verbal complaints of being unable to breathe properly together with increased effort; (It should be noted that persons suffering breathing difficulties may not be able to complain about their discomfort. The problems experienced in trying to breathe will normally result in a physiological response of fighting for air and the subject may thus appear more aggressive. This could lead to the restraint pressure being increased, perpetuating the ‘vicious circle’. Any increased resistance from a person lying in a prone or semi-prone position should be regarded with caution);
      • A violent and noisy person suddenly changes to a passive quiet and tranquil demeanour;
      • Any change in behaviour (both escalative and de-escalative);
      • Blue discoloration to facial skin: (this is difficult or impossible to see with very pigmented skin or darker skin. In these cases cynaosis can be assessed by the colour of the membrane in the eye lids, gums and lips;
      • Loss of or a reduced level of consciousness;
      • Swelling, redness or blood spots to the face or neck;
      • Marked expansion of the veins in the neck;
      • Individual becoming limp or unresponsive.

5. Reducing the risk

5.1. The risk can be reduced by taking the following precautions:

      • Once handcuffed, persons should be raised to their feet and placed on a seat as soon as practicable. Care should, however, be taken not to put pressure on the back as breathing can be restricted even if the person is placed in a recovery position;
      • Monitoring the person’s condition continually whilst being restrained, as death can occur suddenly and develop beyond the point of viable resuscitation within seconds rather than minutes;
      • Whenever possible a 'safety officer' is to be identified.  The role and responsibility of the safety officer is to monitor the health and welfare of the person during restraint; 
      • Getting medical assistance immediately if there is any reason for concern about the person’s condition and notify a supervisory officer if one is not present. Supervisory officers notified of such incidents must attend the scene immediately.

6. In detention

6.1. Should the above occur whilst the person is in detention, a record of what has happened must be made on the Custody Record.

7. Equality impact assessment

7.1. This policy has been assessed with regard to its relevance to race and diversity equality. As a result of this assessment the policy has been graded as having a medium potential impact.

7.2 Attached is the latest equality impact assessment that forms part of the policy review process.


Policy reference: I09 Postural Asphyxia
Policy owner: Head of Human Resources
Contact point: Policy Unit,
Date last reviewed: 27 June 2013
Document last saved: 29 June 2013