Following Acquired Brain Injury, where the person has significant cognitive impairment, it is generally most appropriate to provide care and treatment under the Adults with Incapacity (Scotland) Act 2000. At times it may be necessary to provide care and treatment using compulsory measures i.e. the Mental Health (Care and Treatment) (Scotland) Act 2003. However, these ‘Acts’ do not cover all situations, and in some cases it may be appropriate and necessary to provide care and treatment in emergency situations under ‘common law’ principles.
The term ‘common law’ refers to law which does not come from statutes but instead is based on custom and principles, institutional writings and judicial precedent (case law).
Many of the principles referred to as ‘common law’ are derived from or enshrined in ‘case law’ i.e. legal precedents established by judgements on specific legal cases. Brief summaries of some of the cases most relevant to guidance on consent under common law may be found on the General Medical Council website.
The most important common law principles which may be used as a basis for providing emergency care and treatment to patients who lack capacity are those of:
- Necessity
- Duty of care
The Principles of Necessity and Duty of Care
The common law principles of necessity and duty of care may be necessary in order to provide care and treatment without consent in emergency situations. These principles are described in the General Medical Council Guidelines:
‘When an emergency arises in a clinical setting and it is not possible to find out a patient’s wishes, you can treat them without their consent, provided the treatment is immediately necessary to save their life or to prevent a serious deterioration of their condition. The treatment you provide must be the least restrictive of the patient’s future choices. If the patient regains capacity while in your care, you should tell them what has been done, and why, as soon as they are sufficiently recovered to understand.’ Please see http://www.gmc-uk.org/guidance/ethical_guidance/consent_guidance_scope_of_treatment_in_emergencies.asp
This means that under common law principles it is acceptable to act in a patient’s best interests, without the use of additional legislation (such as the Adults with Incapacity Act or Mental Health Act) in the following circumstances:
a) the care and treatment is urgent and there is not time to consider the use of alternative legislation (e.g. the patient is 
unconscious and requires immediate treatment)
and
b) the care and treatment is necessary to save their life or prevent serious deterioration and/or prevent harm.
In considering whether action can be taken under the principles of necessity or duty of care it may be helpful to consider what would happen if that action was not taken:
- Would failure to act allow greater harm to occur?
- Would failure to act be negligent?
If the person does not rapidly regain capacity, the use of appropriate legislation i.e. Adults with Incapacity or the Mental Health Act should be considered as soon as possible.
Examples of situations where the use of common law (i.e. the principles of necessity and duty of care) may apply include:
- A patient is found unconscious following suspected opiate overdose: the patient requires immediate medical treatment to save their life. Treatment can and should be provided under common law (in the form of the principles of necessity and duty of care). If the patient regains capacity the details and rationale for the treatment provided (when unconscious) should be explained to them. If the patient does not regain capacity, further medical treatment should be provided under Section 47 of the Adults with Incapacity Act.
- A patient who is not detained under the Mental Health Act is found engaging in serious life threatening self-harm: under the common law principles of necessity and duty of care appropriate and proportional action may be taken (i.e. removal of the means of self-harm with physical restraint if necessary) even if the patient is not detained. Once the emergency has been resolved, consideration should be given to the use of the Mental Health Act in order to continue to provide care and treatment.
- Following brain injury a patient is attempting to leave hospital. They are disorientated, distressed, at risk of falls and unaware of common dangers due to their significant cognitive impairment: in this situation it is advisable to use the Mental Health Act to detain the patient in order to prevent them from leaving (either nurse’s power to detain or Emergency Detention). However, if no doctor or appropriately qualified nurse (Registered Mental Health Nurse or Learning Disability Nurse) is immediately available, then the use of the Mental Health Act is not possible. Under these circumstances it is acceptable (under the principles of necessity and duty of care) for any person to keep the patient safe and/or escort them back to the hospital. Consideration should then be given to the use of the Mental Health Act to continue to provide care and treatment.
