Did something go wrong during your sedation for a colonoscopy or gastroscopy?

Understanding procedural sedation: what normally happens

Procedural sedation means giving a patient medication to make them drowsy, relaxed, or unconscious during a medical procedure. During a colonoscopy — a camera examination of the large bowel — or a gastroscopy — a camera examination of the upper digestive tract — clinicians routinely use sedation to keep the patient still and comfortable.

The sedation drugs most commonly used in Australian endoscopy suites include propofol, midazolam, and fentanyl. Each drug affects breathing and blood pressure. Propofol, in particular, can cause rapid drops in both oxygen levels and blood pressure if the team gives too much, or if the patient has underlying health conditions that increase their sensitivity to the drug.

A properly run sedation involves far more than just injecting medication. The clinical team — which may include an anaesthetist, a sedation nurse, or a gastroenterologist depending on the setting — must assess the patient beforehand, attach monitoring equipment, watch the readings throughout the procedure, and respond immediately if anything changes. For more general information about endoscopic procedures and sedation, Healthdirect Australia provides a useful starting point.

When things start to go wrong

Hypoxia and hypotension during sedation do not always announce themselves loudly. A patient under sedation cannot tell the team they feel dizzy or short of breath. That is precisely why continuous monitoring exists — to catch what the patient cannot report.

Some warning signs appear on the monitors before the patient shows obvious physical distress. Others develop quickly and require an immediate response. The clinical team must recognise both.

Each of these signs requires a specific, trained response. Supplemental oxygen, repositioning the airway, reducing or reversing the sedation drug, or calling for emergency assistance — the right action depends on what the monitor shows and how quickly the team acts.

A delay of even two to three minutes in responding to a significant oxygen drop can cause permanent brain damage. Speed is not optional. It is the standard.

A common pattern — where care can break down

Most sedation-related harm during endoscopy does not happen because something unforeseeable occurred. It happens because a predictable risk was not managed properly. The Australian Commission on Safety and Quality in Health Care has identified sedation monitoring and response as a key area of patient safety concern in procedural settings.

Failure to assess risk before sedation

Before any sedation, the clinical team must review the patient’s medical history. Obesity, sleep apnoea, heart disease, lung disease, and advanced age all increase the risk of sedation complications. When a clinician fails to identify these factors — or identifies them but does not adjust the sedation plan — the patient enters the procedure at elevated risk without adequate safeguards in place.

Inadequate monitoring during the procedure

Australian guidelines require continuous monitoring of oxygen saturation and blood pressure throughout any sedation procedure. Some endoscopy units, particularly busy day procedure centres, have experienced situations where a nurse was responsible for monitoring multiple patients, or where monitoring alarms were silenced or ignored. When nobody watches the monitor closely, early warning signs go unnoticed until the patient is already in crisis.

Excessive or poorly titrated sedation doses

Propofol and other sedation agents require careful dose adjustment based on the patient’s weight, age, and health status. Giving a standard adult dose to an elderly patient, a small-framed person, or someone with compromised organ function can push them into a level of sedation far deeper than intended. The team must titrate — meaning give small amounts and wait to see the effect — rather than administering a fixed dose all at once.

Delayed or absent emergency response

When oxygen levels drop or blood pressure falls, the team must act within seconds. Delayed recognition, hesitation about whether to stop the procedure, or failure to call for help quickly enough can all turn a manageable event into a catastrophic one. Some facilities lack adequate emergency equipment or trained personnel to manage a sedation emergency on site.

Premature discharge from recovery

Sedation complications do not always occur during the procedure itself. Some patients develop hypotension or airway problems in the recovery area, particularly in the first 30 minutes after the procedure ends. Discharging a patient before their vital signs have fully stabilised — or leaving them without adequate observation in recovery — creates a second window of serious risk.

Why this matters legally

Every clinician who treats a patient owes that patient a duty of care — a legal obligation to provide treatment that meets the standard a competent professional in the same field would apply. In the context of procedural sedation, this duty covers the entire arc of care: assessment, monitoring, response, and recovery.

Not every complication during sedation amounts to negligence. Some patients experience adverse reactions even when the team does everything correctly. The law does not require perfection. What it requires is that the clinical team acted as a reasonably competent practitioner would have acted in the same circumstances.

The question a court asks is not “did something go wrong?” but “did the team fall below the standard that a reasonable clinician would have met?” If the answer is yes — and if that failure caused the patient’s harm — the law may recognise a claim. For a broader explanation of how this works, see Reframe Legal — Medical Negligence.

When sedation-related hypoxia or hypotension may amount to medical negligence

The NSW Civil Liability Act 2002 is the main law governing medical negligence claims in this state. In plain terms, it sets the standard for what “reasonable care” means and limits certain types of compensation. Under this framework, a claim requires proof that the clinician’s conduct fell below the standard of a competent peer — and that this failure caused measurable harm.

Several specific scenarios in procedural sedation may cross that line.

If the team gave a high-risk patient a standard dose without adjustment — and that patient suffered a serious oxygen drop as a result — the failure to assess and titrate may constitute a breach of the duty of care.

If monitoring equipment was not attached, was malfunctioning, or was not watched — and the patient’s oxygen saturation fell to a dangerous level without anyone noticing — the failure to monitor may be the breach that caused the harm.

If the team recognised a drop in oxygen or blood pressure but delayed responding — perhaps because they wanted to finish the procedure first — that delay may be the act that turned a manageable event into a permanent injury.

If the facility discharged the patient from recovery before their vital signs were stable — and the patient collapsed at home or in the car park — the premature discharge may form part of the negligence claim.

Each of these scenarios links a specific failure to a specific harm. That connection — between what the team did or failed to do, and what happened to the patient — is the core of any negligence claim.

When harm becomes long-term or permanent

A sedation event that goes unmanaged for even a few minutes can produce harm that lasts a lifetime. The brain is extraordinarily sensitive to oxygen deprivation. After approximately four minutes without adequate oxygen, brain cells begin to die. After ten minutes, the damage is often irreversible.

Physical consequences

Patients who survive a serious hypoxic event during sedation may wake up with cognitive impairment — difficulty thinking, remembering, or speaking. Some experience motor deficits, meaning they lose control of movement in their limbs. Others suffer damage to the heart muscle from prolonged low blood pressure. A small number do not survive.

Psychological consequences

Waking up in an intensive care unit after what was supposed to be a routine bowel check is a profoundly disorienting experience. Many patients develop post-traumatic stress disorder. Family members who witnessed the emergency or received a call that their loved one had collapsed during a colonoscopy also carry significant psychological burden.

Financial consequences

Long-term brain injury requires ongoing rehabilitation, specialist care, and often full-time support at home. Many patients cannot return to work. Some require modifications to their home or vehicle. The financial impact compounds over years — and in severe cases, over decades.

What compensation can cover in sedation-related negligence cases

NSW law allows people harmed by medical negligence to seek compensation for a range of losses. This includes pain and suffering, lost income — both past and future — the cost of ongoing medical treatment, and the cost of care provided by family members or professional carers.

In sedation-related cases, where the harm is often severe and permanent, compensation claims can be substantial. The figures below reflect general ranges across different levels of injury severity.

Each case is assessed on its own facts. These figures are general ranges only. Brain injury following sedation-related hypoxia often falls into the severe category, where compensation accounts for lifetime care needs and total loss of earning capacity.

Time limits apply in NSW. Generally, a person has three years from the date they knew — or ought reasonably to have known — that they suffered harm as a result of negligence. For cases involving cognitive impairment, the rules around time limits can be more complex.

Bringing it together — do the pieces fit?

If you or someone you love experienced a serious event during a colonoscopy or gastroscopy, it can be hard to know what questions to ask. The medical records may be difficult to read. The clinical team may have offered little explanation. You may have been told it was “just one of those things.”

But the law asks specific questions — and those questions have answers that come from the records, the monitoring data, and the clinical guidelines that applied at the time.

Understanding how a negligence claim works can help you decide whether to take the next step. Reframe Legal — How Medical Negligence Claims Work in NSW explains the process in plain language.

You don’t need certainty to understand your position

Many people who experienced a serious sedation event spend months — sometimes years — wondering whether what happened was normal. Clinicians rarely volunteer the information that something went wrong. Medical records can be dense and difficult to interpret without training.

Legal clarity does not require you to already know the answer. It comes from examining the facts: what the records show, what the monitoring data captured, what the guidelines required, and what the team actually did. A lawyer with experience in medical negligence can read those records and identify whether the standard of care was met.

Uncertainty is not a reason to do nothing. For people who want to understand their rights around informed consent — including whether the team properly explained the risks of sedation before the procedure — Reframe Legal — Informed Consent and Medical Negligence provides a detailed explanation.

If you have concerns about the conduct of a specific clinician, AHPRA — Australian Health Practitioner Regulation Agency is the body that registers and regulates health practitioners across Australia. AHPRA handles complaints about individual practitioners separately from any legal claim.

About the lawyer behind this article

Dr Rosemary Listing is a NSW lawyer with a PhD focused on medical negligence. Her academic background gives her an unusual ability to read medical records, interpret monitoring data, and identify where clinical care fell below the accepted standard.

In her experience, the harm in these cases rarely comes from the procedure itself. It comes from what the team failed to notice, failed to act on, or failed to document. A few minutes of inattention can produce decades of consequences for the patient and their family.

People who approach Dr Listing are not looking to blame anyone. Most want to understand what happened to them — and whether the care they received met the standard they were entitled to expect. That is the question her work is designed to answer.

Dr Listing’s role is to examine the facts, apply the legal standard, and give her clients an honest assessment of where they stand. She does not offer false reassurance — and she does not dismiss concerns that deserve careful examination.

This article is general legal information only. It does not constitute legal advice. Each person’s circumstances are different. The law discussed applies to New South Wales, Australia. Time limits apply to legal claims.