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Anaesthetic Negligence

Catherine Henry Lawyers
Catherine Henry Lawyers

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Anaesthetic Awareness

Anaesthesia is a medically induced state of unconsciousness and pain relief, used to help people to undergo surgery. Anaesthesia may be used locally by creating a numbing sensation in a particular part of the body while maintaining consciousness or globally (also known as general anaesthetic) by causing a person to lose consciousness and sensation for the duration of a procedure.

Examples of anaesthetic drugs

Fentanyl is an opioid drug, now commonly used in anaesthesia and pain management. It is more potent than morphine. It has a rapid onset and usually lasts between one and two hours.

Midazolam is a type of benzodiazepine drug. It is used prior to the administration of general anaesthesia to induce sleepiness, decease anxiety and cause a loss of ability to create new memories. Depending on the manner of administration, Midazolam commences working within 15 minutes of administration. The effects last between one and six hours.

Nitrous oxide, also known as laughing gas, is a gas compound that has been widely used in anaesthesia and pain management for many years. It is often mixed with oxygen and inhaled through a mask. Nitrous oxide is often used in dentistry procedures and also during childbirth as the patient may remain awake and conscious.


Both general and local administration of anaesthetic carry a degree of risk. Anaesthetic administration is a careful balancing act as administering too little or too much anaesthetic can lead to serious harm.

Administering too little anaesthetic can prevent the drug from fully taking effect. This may mean that a person experiences pain during a procedure or, in the case of general anaesthesia, a person regains consciousness during a procedure.

Administering too much anaesthetic can lead to more serious, potentially life-threatening effects. Over-administration can cause various systems to slow down or cease function entirely. This can include a significant reduction in breathing or blood circulation, or a complete closure of airways. A sustained period of reduced air or blood flow can cause serious damage to the brain.

Best practice

Since anaesthesia carries such significant risks to the patient, it should only be induced in the right circumstances and with a sufficient number of qualified staff present.


In order for a patient to give proper consent, a doctor must ensure that the patient is aware of both the procedure to be undertaken as well as any risks involved with the procedure and the use of anaesthesia. This could be – but often is not – provided in a written format, such as a pamphlet or brochure.

Prior to the procedure, a doctor must undertake an assessment of the patient to determine whether they are at risk of any adverse effects. This assessment includes reviewing past reactions to anaesthesia, current medications and current medical conditions or allergies suffered by the patient. Indicators of increased risk include age, weight, chronic disease, and previous adverse reactions to sedation. If this preliminary assessment reveals any risk factors, a full assessment of the patient’s airways, cardiovascular system and respiratory system should be undertaken.

The proceduralist

In all but the lightest of conscious sedation, the staff on hand must include a proceduralist, the practitioner administering the sedation and an additional staff member. If general anaesthesia is to be administered, an anaesthetist or other specially trained practitioner must be present, as well as a fourth person to assist the anaesthetist.

The practitioner administering the anaesthesia must be highly trained. If they are not an anaesthetist, they must have a thorough understanding of the effects of the medication to be administered, the ability to monitor the patient and modify the dosage in response to their reaction and the ability to detect and manage any complications which arise.

Anaesthetic awareness

When a patient receives anaesthetic prior to a procedure, the surgeon and the anaesthetist both have duties of care to ensure that the anaesthetic has taken effect prior to the commencement of the procedure.

If a procedure is commenced prior to anaesthesia having taken effect, the patient may not be appropriately sedated and may experience pain and trauma as a result. This scenario is commonly referred to as anaesthetic awareness because the patient is aware and awake during the operation.

It has been estimated that the incidence of anaesthetic awareness is as much as 10%.

How we can help

If you are looking for information or assistance in regard to what you believe may have been anaesthetic error, we can help you navigate the process.

We have acted for clients who have been administered too much anaesthetic and also those who were not administered enough anaesthetic and remained aware during the procedure.

Our health law team is highly respected in the health and medical litigation area, with specialist knowledge accumulated over more than 30 years.

Our team can assist you by providing expert advice and legal support regarding your options. Contact us today.

*The material provided in our information sheets is for general knowledge only and is not a substitute for independent legal advice. For further information about the issues affecting you, please contact one of our experienced and professional lawyers for expert advice.

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