09 Apr 2011
By: SALMA KHALIK
THIRTY-SEVEN minutes is not a long time, but it can make a life-and-death difference to someone having a heart attack.
Besides lives, more heart muscles have been saved in the past couple of years, simply by having paramedics verify on the spot if it is a heart attack and what type it is.
They do this by running an electro-cardiogram (ECG) on the suspected heart patient at the scene to find the extent of the blockage, and then transmitting the reading to the hospital even before the patient is put in the ambulance.
While the patient is on the way, the hospital prepares to receive him, and doctors assess the need for an immediate angiogram, a treatment in which a balloon is inflated in an artery to break up a clot. The sooner the artery is unblocked, the better the patient's chances of survival.
Associate Professor Marcus Ong said this expedited emergency procedure has almost halved the time to clear the choke in the patient's plumbing and saved about half the people who would otherwise have died. This works out to between five and 10 people a year.
He goes by "door-to-balloon" time, that is, from the time the patient passes through the hospital door to the time he gets that angiogram. The median time has gone down from 88 minutes to 51 minutes.
The difference: 37 minutes.
Prof Ong, unveiling the results of a nationwide trial on the first day of the two-day Annual Scientific Meeting of Singapore General Hospital (SGH) yesterday, said 37 minutes is also precious for reducing damage done to the patient's heart muscle. These muscles start to die about 90 minutes after the onset of a heart attack. The sooner blood flow is restored, the more muscle is saved.
People with weakened or dead heart muscles are more likely to suffer heart failure, a degenerative condition in which the heart does not pump strongly enough to supply the organs with enough blood. Shortness of breath and swollen ankles are signs.
Dr Ong, a clinician-scientist and senior emergency medicine consultant at SGH, was the lead investigator of the study that involved all public hospitals, the National Heart Centre and the Singapore Civil Defence Force (SCDF), which runs the nation's 46 emergency ambulances.
Explaining how time – and lives – have been saved, he said all 250 paramedics have been trained to do ECGs at the scene; these cannot be done on board speeding ambulances because the vehicle movements skew readings.
Paramedics have also been trained to administer blood thinners and medicine that opens up the arteries, starting damage control early.
Before December 2008, when this study began, patients were given an ECG only on arrival in the hospital, and a medical team activated after that.
Paramedics take an extra 39 seconds to do an ECG at the scene, but hospitals and doctors use the ambulance's travel time to get ready to deliver treatment as soon as the patient arrives.
When a heart attack happens at night, doing the ECG on site is even more crucial because doctors on call need time to be alerted and return to the hospital.
Prof Ong said this is why people who suspect they have had a heart attack should always call 995 for an ambulance rather than try to get to the hospital on their own, even if they live nearby.
About 100 people a month need emergency ballooning following a heart attack.
Since December 2008, SCDF ambulances have sent an average of 168 ECG readings a month to hospitals – more than five each day.
All hospitals havelogged better door-to-balloon times, but a gap still yawns between the best and the worst times. Prof Ong declined to reveal these, but said the average ranges between 20 and 60 minutes.
All hospitals have managed to shave about half an hour off their times.
Before on-site ECGs became routine, only half the patients were ballooned within 90 minutes of arrival.
Now the majority are.
Email: salma@sph.com.sg
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