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Harnessing Local Data to Inform Decision-Making in Critical Care

Ethical discussions are a crucial part of Dr Pauline Yeung’s routine as a critical care doctor treating patients at a “brittle” time in their diseases. And now she is seeking to better inform these decisions through research into outcomes at Hong Kong hospitals.

Dr Yeung, Clinical Assistant Professor in Practice, Division of Respiratory and Critical Care Medicine, joined the University of Hong Kong’s LKS Faculty of Medicine (HKUMed) in early 2019. She is the first person appointed to this position for critical care in the Department of Medicine.

This role allows her to continue her clinical work as an Honorary Associate Consultant in the intensive care unit at Queen Mary Hospital (QMH) alongside research and teaching.

“To come up with locally relevant data is extremely important,” she said. “We know that Chinese people, who make up the bulk of our population, do not behave entirely the same as other ethnic groups.”

Her current path was inspired by a research fellowship at Massachusetts General in Boston in 2017, which encouraged her to pursue research on her return to Hong Kong.

Dr Yeung’s research centres on extracorporeal membrane oxygenation (ECMO), a technique that uses a machine to oxygenate a patient’s blood outside the body, supporting the heart and lungs.

First developed in the 1950s, improvements in the technology have seen ECMO usage grow in the past 15 years, Dr Yeung said.

ECMO is seen as the “cool” technique in the arsenal of critical care options, Dr Yeung said, drawing many to seek out training for the technique. The increased attention on this resource-intensive treatment has made research into outcomes particularly important to help address questions surrounding ethics and risk, she explained.

Dr Yeung inserts part of the ECMO circuit components into a patient who is covered by a blue sheet
Dr Yeung (right) inserts part of the ECMO circuit components into a patient

“If you know the chances of helping a patient, then you can make educated decisions. And if you don’t have that number, it’s really very hard to gauge whether you should offer [ECMO] that has inherent risks to a patient.”

Dr Yeung’s focus is veno-arterial ECMO (V-A ECMO), which is used in cases where the pumping function of a patient’s heart is weak or absent. The technique involves taking blood from the venous system and returning it to the arterial system, replicating the heart’s role until the patient recovers.

Earlier this year, she submitted a paper examining outcomes for patients who received, V-A ECMO, veno-venous ECMO and extracorporeal membrane oxygenation-cardiopulmonary resuscitation (ECMO-CPR) across the seven centres in Hong Kong.

The study compared clinical outcomes in patients from 2010 to 2019 treated at high-volume centres — those that see 20 or more ECMO cases each year — against those in low-volume centres that treat less than 20.

Dr Yeung said Hong Kong’s high ECMO centre-to-population ratio means cases are more widely distributed, limiting the benefits usually seen at high-volume centres. She would therefore like to examine the potential effects of consolidating ECMO services in the city.

For patients who receive ECMO-CPR at QMH, around two out of 10 make it out of the hospital with good neurological recovery, Dr Yeung said, adding that while the number does not appear high, without this technique, none of the patients would survive.

This type of research is crucial for patients and their families who are increasingly requesting “numbers, robust answers and predicted probabilities” when considering treatment options, Dr Yeung said.

Dr Yeung  with her intensive care unit clinical team, all in light blue scrubs, stand in a hospital ward
Dr Yeung (third from left) with her intensive care unit clinical team

A graduate of HKUMed’s Bachelor of Medicine, Bachelor of Surgery programme, Dr Yeung describes treating patients as her “calling”. And she particularly enjoys how the quick decisions made in critical care have a readily perceivable effect on the patient’s condition and how teamwork is integral to the specialty.

“If you are just starting in critical care, you benefit from working closely with your seniors,” she said. “You learn a lot from watching them, how they do things, how they make decisions… it’s wonderful mentorship.”

Her ongoing research focuses on using echocardiography at a patient’s bedside to examine how their heart interacts with the ECMO machine if the flow is increased or decreased.

Average cardiac output is 4.5 to 6 litres a minute, Dr Yeung said, explaining that an ECMO machine can be adjusted to as low as 1 litre a minute to support a patient to up to 4 litres a minute when it is necessary to overtake the heart’s function. However, providing unnecessarily high ECMO flows can damage the patient’s heart.

A diagram showing how V-A ECMO pumps oxygenated blood into the body
A diagram of V-A ECMO

“There are no good guidelines on how much to give, and that is because it is multifactorial,” Dr Yeung said. “And we are still in a period of this exponential use of ECMO, maybe without the most robust of pre-clinical or early clinical data, which is what we are trying to [achieve] with our echocardiography studies.”

This research has taken almost three years because just 30 to 40 patients receive this type of treatment at QMH each year, limiting the potential for data collection.

As a result of these limitations, Dr Yeung is eager to streamline access to ECMO and ICU data in Hong Kong to allow for more research in this field. And she views her dual role as a clinician and academic as providing a unique opportunity to drive collaboration across the territory.

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