Best interests decisions

Contents

Overview

When a patient lacks capacity to make a healthcare decision, English law requires that decision to be made in the patient's best interests. This is not a subjective judgement of what the clinician or family would prefer — it is a structured, legally defined process under the Mental Capacity Act 2005. The ICU clinician must understand the process, document it rigorously, and be prepared to explain decisions to families, colleagues, and if necessary, the courts.

Legal Framework

The Mental Capacity Act (MCA) 2005 governs decision-making for patients lacking capacity in England and Wales. The Act's five statutory principles are:

  1. A person must be assumed to have capacity unless it is established that they lack it.
  2. A person is not to be treated as unable to make a decision unless all practicable steps to help them do so have been taken without success.
  3. A person is not to be treated as unable to make a decision merely because they make an unwise decision.
  4. An act done, or decision made, under this Act for or on behalf of a person who lacks capacity must be done, or made, in their best interests.
  5. Before the act is done, or the decision is made, regard must be had to whether the purpose for which it is needed can be as effectively achieved in a way that is less restrictive of the person's rights and freedom of action.

The MCA applies to patients aged 16 and over. Children under 16 are governed by the Children Act 1989 and common law principles.

Assessing Capacity

Capacity is decision-specific and time-specific. A patient may have capacity for some decisions but not others, and this may change over time.

The MCA two-stage test for capacity:

Stage 1 — Diagnostic threshold: Is there an impairment of, or disturbance in, the functioning of the mind or brain? This may be permanent (dementia, intellectual disability) or temporary (delirium, unconsciousness, intoxication, acute psychosis).

Stage 2 — Functional test: As a result of that impairment, is the person unable to:

  • Understand the information relevant to the decision
  • Retain it long enough to make the decision
  • Use or weigh the information as part of the decision-making process
  • Communicate their decision (by any means)

All four elements must be impaired for the person to lack capacity. Capacity should be formally assessed and documented, ideally by the senior clinician responsible for care.

The Best Interests Standard

Section 4 of the MCA sets out the checklist for determining best interests. The decision-maker must:

  • Consider all relevant circumstances
  • Consider whether and when the person may regain capacity
  • Involve the person as much as possible — encouraging participation even if full capacity is absent
  • Consider the person's past and present wishes, feelings, beliefs, and values, including any written statements
  • Take into account the views of relevant people (see below)
  • Not be motivated by a desire to bring about the person's death

Best interests is not a medical concept alone. It includes the person's emotional, psychological, social, cultural, spiritual, and moral interests, not just their clinical condition. A clinician who considers only the medical facts is applying an incomplete best interests analysis.

Consulting Relevant People

The MCA requires the decision-maker to take into account the views of people who can speak to what the patient would have wanted:

  • Spouse, civil partner, or anyone in a long-term caring relationship
  • Close relatives
  • Any named person the patient asked to be consulted
  • Any person with a Lasting Power of Attorney (Health and Welfare)
  • Any Court-Appointed Deputy with authority over the relevant decision

Where no such person is available to be consulted, and the decision is about serious medical treatment, an Independent Mental Capacity Advocate (IMCA) must be appointed (MCA s.37). The IMCA represents the patient's interests and must be consulted before any serious medical treatment is provided.

Family members in England and Wales do not hold legal decision-making authority unless they have a valid, registered Health and Welfare LPA that specifically covers the decision in question. Their role is as consultees — providing information about the patient's likely wishes — not as decision-makers.

Treatment Decisions in Practice

Common best interests decisions in the ICU include:

Intubation and ventilation: In a patient who cannot consent (unconscious, delirious), intubation may be provided as an urgent best interests decision when the clinical situation demands it and delay would cause harm. Documentation of capacity assessment and the best interests reasoning should follow promptly.

Withdrawal of life-sustaining treatment: When continued treatment is not in the patient's best interests — because it is futile, burdensome, or contrary to their known wishes — withdrawal is legally and ethically permissible. This is not euthanasia; it allows the underlying disease to take its natural course. The best interests assessment should be documented in full, including consideration of the patient's wishes, consultation with relevant people, and the clinical rationale.

Feeding and hydration: Clinically assisted nutrition and hydration (CANH) may be withdrawn as a best interests decision. For patients in a prolonged disorder of consciousness (PDOC), Court of Protection approval is required before withdrawal, following the Supreme Court ruling in An NHS Trust v Y (2018).

Conflict and Escalation

Conflict arises when family members disagree with the clinical team's best interests assessment, or when members of the clinical team disagree with each other.

First response: Invest in communication. Meet with the family, provide clear prognostic information, explore their concerns, and allow time. Many conflicts resolve with patience, honesty, and repeated engagement.

Clinical ethics committee: In complex or persistent conflict, a formal ethics consultation provides a structured, multi-perspective review. The outcome is advisory, not binding.

Court of Protection: Has jurisdiction over all decisions relating to people lacking capacity. It can issue declarations on the lawfulness of proposed treatment (or withdrawal), and can appoint deputies. The Court can be approached where there is genuine uncertainty about the lawfulness of a proposed action, or persistent unresolvable conflict. The process is not as slow as commonly assumed — urgent applications can be heard within hours.

Clinicians are not legally required to obtain Court of Protection approval before withdrawing treatment in most cases, unless the patient is in PDOC. However, seeking the Court's view in cases of genuine uncertainty is appropriate and protects all parties.

Viva Questions

How do you apply the best interests standard when deciding to withdraw life-sustaining treatment from a patient who lacks capacity?

The best interests assessment under the MCA 2005 is a structured process, not simply a clinical opinion. I would begin by confirming the patient lacks capacity using the two-stage MCA test and documenting this. I would then consider all relevant circumstances: the patient's clinical condition, prognosis, and the likely burden and benefit of continued treatment. Critically, I would seek information about the patient's previously expressed wishes, values, and beliefs — from family members, GP records, any written advance statement, and the patient's own documented views. If an ADRT refusing the treatment exists and is valid and applicable, it is legally binding. If a Health and Welfare LPA exists, the attorney's decision must be obtained. Otherwise, family members are consultees whose views inform the decision. If no family is available to be consulted, an IMCA must be instructed. Having gathered this information, I would make the decision in the patient's best interests, weighing clinical evidence against their known values and the views of those who know them. The decision and the process by which it was reached must be documented in detail in the medical notes. A clinical ethics consultation or Court of Protection application should be considered where there is genuine uncertainty or unresolvable conflict.

What is the role of the Independent Mental Capacity Advocate and when must one be instructed?

An IMCA is a statutory advocacy service mandated by the MCA for patients who lack capacity, have no family or friends who can be consulted, and require a serious medical treatment decision. Serious medical treatment includes treatment involving significant risk, major consequences (such as starting, stopping, or withholding life-sustaining treatment), where there is a fine balance between benefit and burden, or where there is a disagreement between those involved in the decision. The IMCA's role is to represent the patient's interests and ascertain what the patient would have wanted. The IMCA is not a decision-maker; they provide information to the treating team and may challenge decisions they believe do not serve the patient's best interests. In the ICU, the IMCA is most commonly required for patients with no family — those who are homeless, estranged from relatives, or whose family cannot be contacted. The IMCA referral should not delay urgent treatment if delay would cause harm, but should be made as soon as practicable in any non-urgent serious medical treatment decision for an unbefriended patient.

A family insists a patient "would have wanted everything done." How do you approach this?

I would begin by exploring what the family means by "everything" — ensuring they understand the specific interventions under discussion and what outcomes they realistically achieve in this patient's clinical context. I would acknowledge their love and concern for the patient and validate the difficulty of the situation. I would then ask what they know about the patient's own views: did the patient ever discuss what they would want at the end of life? What did they value most? Were they afraid of pain, of being dependent, of prolonged unconsciousness? This line of questioning often reveals that the family's insistence reflects their own grief rather than the patient's known preferences. If I have a clinical view that further life-sustaining treatment is not in the patient's best interests — because it is futile or more burdensome than beneficial — I would explain this clearly and compassionately. I would document the conversation. If conflict persists, I would involve a senior colleague, offer a formal family meeting with the palliative care team, and consider a clinical ethics committee referral. I would not simply capitulate to family pressure if I believe treatment is not in the patient's best interests. Family members are consultees, not decision-makers, and the treating team retains legal responsibility for the decision.