Health care professionals have a duty to provide patients with adequate information to make an informed decision before undergoing any medical procedure. Only then can a patient provide consent, either expressly or impliedly, to undergo that medical procedure. However, in limited circumstances, health care practitioners are able to provide less information to a patient or, even, seek consent from third parties.
As a rule, health professionals must obtain a consumer’s consent before undertaking any health procedures. This applies even when the proposed treatment would clearly benefit the consumer, and when failure to treat the consumer may result in harm that may have been avoided. The principle applies not only to treatment but also to diagnostic and investigative procedures.
The rule of consent is based on the recognition that competent individuals are entitled to make their own healthcare decisions – even if their decisions may sometimes appear to the health professional as not being in their best interests.
A health professional who treats a consumer without informing them adequately about the procedure (see “What information must be given to a patient?”) can be subject to an action in negligence; if a patient’s consent is not obtained, the health professional can be subject to an action in trespass to the person (commonly called assault).
The law has increasingly emphasised that a consumer must be given adequate information to enable them to make an informed decision about whether to consent to a healthcare procedure. The information that must be given to a consumer includes:
• information about their condition;
• the options for investigation or treatment and their advantages and disadvantages, including what is likely to happen if nothing is done; and
• what the doctor recommends.
Most of the court cases relating to the provision of adequate information to the consumer have concerned the type and amount of information that needs to be given about the potential risks of a proposed procedure.
The High Court of Australia said in Rogers v Whitaker  HCA 58 that a doctor must warn a patient of risks that are “material”, and that a risk is material if:
in the circumstances of the particular case, a reasonable [that is, an “ordinary”] person in the patient’s position, if warned of the risk, would be likely to attach significance to it or if the medical practitioner is or should reasonably be aware that the particular patient, if warned of the risk, would be likely to attach significance to it.
Essentially, this means a consumer should be warned of risks that are likely to be significant to them. This will depend upon:
• the person’s condition;
• the nature of the treatment (more information may be needed for a “cosmetic” procedure than for surgery that is clinically indicated for the consumer’s health or wellbeing);
• the seriousness or likelihood of the risk (serious risks like death, stroke or paralysis should be mentioned even if they are remote; similarly, minor injuries like bruising after venepuncture (entry into a vein) may be material if they are frequent);
• the consumer’s desire for information (questioning, anxious consumers may need to be given more information); and
• the general surrounding circumstances (less information may be justified for life-threatening or urgent procedures than for those that can be delayed).
The test is whether the risk in question is so serious, or so likely to occur, that it is likely to influence the decision of an ordinary person in the person’s position whether to agree to the procedure; or whether the health professional should know that the risk would be significant for the particular individual.
Ultimately, this may depend on the circumstances of a particular case. While there is no ready guide, there have been a number of cases alleging negligence against health professionals for failing to disclose a material risk. In any event, practitioners should always try to respond truthfully and adequately to a consumer’s questions. Therefore, as a health consumer, it is advisable to question health professionals thoroughly, to resolve any doubts about the consequences of a treatment or procedure.
There are several situations in which less information may be justifiable.
The first is an emergency. Here, treatment may be given without any information or consent, if it is necessary to protect the person’s life or health.
For instance, if an individual is unconscious, a health professional may perform whatever procedures are reasonably necessary in the circumstances. It is not necessary to obtain the consent of the consumer’s next of kin, although where practicable, that is generally done as a courtesy and relatives do have lawful authority to consent in some circumstances (see “Capacity to consent”).
The second case in which less information may be required is when the person waives the right to be given information. This would justify the practitioner not fully discussing the risks of a proposed procedure. However, the individual must still be given sufficient information about the procedure to give an effective consent to it.
The third situation is a health professional’s limited discretion (therapeutic privilege) not to disclose information where they have reasonable grounds to believe that disclosing the information may harm the person (e.g. if the individual is suicidal or mentally ill). Even in this case, however, a health professional may not be justified in withholding information if a consumer asks a specific question.
Consent may be express or implied. Hospitals usually require patients undergoing surgery to sign a consent form that often states the person has been given information about the procedure and has consented to it. The fact that a person has signed such a form is evidence they were informed and consented to the surgery, but it is not conclusive evidence. A court may still examine the circumstances in which the form was signed to determine what the person was really told and understood. However, in most cases, consent is implied from a person’s actions, such as rolling up a sleeve to receive a flu vaccine. This type of consent is generally effective, though the law may be less ready to accept that consent was present if the procedure poses a substantial risk to the individual.
Consent must be freely given. A person should not be pressured by a health professional or anyone else into deciding on a particular course of treatment.
The principles that people may not be given healthcare treatment without their consent, and they are entitled to adequate information to make an informed choice, apply to competent adults (that is, to people over 18 who are able to understand their condition and the options for treatment).
If the person is a child (under 18), either parent or a guardian may generally consent to a procedure, and the parent or guardian is entitled to the same information as an adult patient. However, a child may also be able to consent if sufficiently mature to understand the procedure. This will depend on the child’s age and level of maturity, and the particular procedure. Mature minors can consent to simple procedures for their own good, such as a vaccination. On the other hand, greater maturity and understanding will be required for procedures that are risky or contentious, such as contraception.
In the case of non-therapeutic sterilisation of a mentally impaired minor, court authority is required; the parent alone cannot consent.
People who are seriously physically impaired or who have an intellectual disability or mental illness may not be able to consent to medical treatment. Again, this depends on the patient’s level of understanding, their ability to communicate and the nature of the procedure.
It is presumed that patients with an intellectual disability are able to make their own medical decisions unless the doctor considers, after careful consideration, the patient cannot understand.
If they are not competent to decide, consent must be sought from someone else. If the person is over 18 and incapable of giving consent, consent may be given by a “person responsible” under part 4A of the Guardianship and Administration Act 1986 (Vic); see Guardianship and medical treatment.
Electroconvulsive therapy is discussed in Mental illness.