December 3, 2024
SINGAPORE – A 35-year-old Singaporean woman living in South Korea made the headlines last week after it was reported that she had fallen into a vegetative state after suffering cardiac arrest during gastroscopy.
The Straits Times reported that Ms Tong Ming Yan, a former teacher, had suffered irreversible brain damage following the procedure under sedation as part of a comprehensive health screening.
What are the risks associated with the procedure?
AskST takes a look.
Q: What is gastroscopy, and why do you need to be sedated for it?
A: Gastrointestinal endoscopy, otherwise known as gastroscopy, is an examination of the upper gastrointestinal tract, using a long flexible telescope to do so.
“It is a simple and useful way for doctors to examine the oesophagus, stomach and the first part of the small intestine called the duodenum,” said Dr Melvin Look, a consultant surgeon in gastrointestinal, laparoscopic and obesity surgery.
Describing gastroscopy as a “very safe procedure for diagnosis”, the director of private practice PanAsia Surgery said gastroscopy is usually done to investigate symptoms such as reflux, abdominal discomfort and bloating.
The procedure can also be conducted for therapeutic reasons, such as to remove polyps and cancers.
While the patient can be awake for the procedure, this can be uncomfortable as air may be used to distend the stomach for better visualisation, Dr Look said, noting that most gastroscopy cases are conducted under moderate sedation, allowing the patient to sleep for about 10 to 15 minutes.
Q: Why would gastroscopy be included as part of a health screening?
A: “Routine screening gastroscopy is frequently offered in countries such as Japan and South Korea, because the risk of stomach cancer in those countries is relatively high,” said Dr Look.
Data from the National Cancer Centre of Korea identified stomach cancer as the most common type of cancer in South Korea between 1999 and 2018.
Dr Look said that routine screening gastroscopy is less common in Singapore due to the decline in incidences of stomach cancer here in recent years.
“There is, however, a moderate risk in Chinese males above the age of 50, and in anyone who has a family history of stomach cancer,” he cautioned.
Patients with a history of helicobacter pylori infection of the stomach – characterised by symptoms such as burning pain in the stomach and nausea – could benefit from a stomach examination due to a higher risk of cancer.
While screening gastroscopy is not routinely done here, doctors may recommend it if a patient is already scheduled for a colonoscopy to screen for colorectal cancer and polyps, as the gastroscopy will take no more than 10 minutes, said Dr Look.
Q. What are the risks associated with gastroscopy, and how likely is cardiac arrest to occur as a result of the procedure?
A: The procedural risks associated with gastroscopy are “very small”, said Dr Look.
He noted though that there may be a risk of bleeding or perforation of the stomach, should large polyps or cancers be found and removed during the procedure.
The risks of sedation for gastroscopy are also small when administered by an experienced doctor or anaesthetist, he said.
“There may, however, be a small risk of cardiac and respiratory problems in elderly patients or those who are frail and have pre-existing medical problems.”
Dr Look noted that gastroscopies performed in Singapore are “extremely safe” as they are done by specialists in gastroenterology or general surgery, unlike in other countries where gastroscopies can be performed by general practitioners or nurse practitioners.
“Even in public hospitals where procedures may be done by trainees, it is always under the supervision of a specialist,” he said.
While gastroscopy does not directly affect the heart, studies have shown that three to four cases of cardiac arrest happen during or after the procedure for every 10,000 patients.
This usually happens to patients who already have a cardiac condition, said Dr Look.
“Cardiac arrest can also occur if there is an obstruction of the airways during sedation that results in a drop in oxygenation levels,” he said, adding that over-sedation could also lead to a drop in blood pressure that precipitates a cardiac arrest.