In english   
EKL
 Põhikiri
 EKL juhatus
 Koosolekud
 Astu liikmeks
Eesti Kiirabid
 Abi kutsumine
 Piirkonnad
 Kodulehed
Info
 Uudised
 Heategijad
 Kiirabi suvepäevad
 Juhendid kiirabitöötajale
Toimetamised
 Valujoonlaud
 Kvaliteediindikaatorid kiirabis
 Konverentsid
 Projektid
 Koolitus
 Terapeutiline hüpotermia
Põnevat
 Lugemist
 Pildialbumid
 Internet
Seadusandlus
 Katastroofimeditsiin
 Terviseamet

PREHOSPITAL TROMBOLYSES

Ettekandja: Ari Kinnunen

Kuupäev: 01.01.2001

Üritus: NORDIC-BALTIC EMS CONFERENCE “TALLINN 2000”

Ari Kinnunen, MD, PhD

Sudden chest pain: why thrombolysis treatment?

* The size of the infraction is reduced by 20 - 50%
* The risk for severe cardiac insufficiency or cardiogenic * chock is reduced by 50%
* Reduction in mortality even up to 25%
* Myocardial function of the left ventricle is preserved
* Reduction in severe arrythmia
* Poor prognosis = > better effect!

Delay less than 3 hours; every minute counts!

Sudden chest pain: need for thrombolysis?

* The prognosis of the patient is related to the size of the infraction
* The final size of the infraction is determined many hours after the start of the symptoms
* Thrombolysis can minimize the damage to the heart
* Every second AMI patient should receive thrombolysis treatment in time

Sudden chest pain: how to evaluate?

Sudden onset of symptoms?

* 10 - 20% have no chest pain =>
* breathing difficulty, arrhytmia or sudden loss of conscience

Can the symptoms be related to cardiac ischemia?

Sudden chest pain: how to evaluate?

Recent ECG-changes?

* ST-segment elevation in at leasr two leads
* Chest leads 2.0 mm or more
* Extremity leads 1.0 mm or more
* Left Bundle Branch Block with typical clinical picture for AMI
* ST-segment depression in V1 - V3 leads related to posterior wall injury


Sudden chest pain: how to evaluate?

Symtoms started in less than 12 hours?

* Also ealrier if no evident Q-waves

Clinical picture and ECG-changes can be related to

* Early repolarization?
* Perimyocarditis?

Are there contraindications?

* Recent (2-3 weeks) ischemic brain insult
* Recent (2-3 weeks) major trauma or operation
* Gastrointestinal bleeding during the previous month
* Known coagulation disturbance
* Strong suspicion for dissected aortic aneurysm
* Intracranial or intrathetical operation during the previous 2 month
* Known tumor in the Central Nervous System
* Disturbance in brain blood circulation during the previous 6 months
* Pregnancy
* CPR with conciderable chest injuries
* Recent laser treatmient of retina
* Hypertension (> 200/110 mmHg) not reacting to treatment

Thrombolysis not indicated when

* No ECG-changes
* Only T-wave abnormalities or ST-segment depression (except for V1- V3)

PATIENT #1

Female, age 54
Previously:
hypertension
no medication except for hormone substitution
Emergency response:
pain started previous evening ~22.00
call to dispatch center 05.05
first BLS unit on site 05.16
12 channel ECG 05.25
call for Medi-Heli 05.36
Medi-Heli attending patient 05.50
thrombolysis started 06.05

Some 8 hours from onset of continuous pain

transport started 06.29
in hospital 06.46
History:
feeling of "heaviness" and chest pain when leaving work the previous day around 16.00
various pain had continued during the same evening , but the pain had allowed going to sleep.
BLS unit requests Medi-Heli to site
Findings:
On floor, pale, cold sweat, pulse frequency 53, blood pressure 95/70, oxygen saturation 98%, central chest pain
ECG: sinus rhythm, R-depression, ST-segment elevation V3-V4
Pre-hospital diagnosis: AMI
Treatment:
Oxygen by face mask
Ringer infusion 500ml
Morphin 4 + 2 + 2 mg
Metoclopramid 10 mg
Reteplase 10 + 10 units
Heparin 5000 units
Nitrate infusion 0,1 mg/ml 15 ml/h
Transport:
With ground ambulance
No problems or complications
Feed back:
AMI confirmed
Successful thrombolysis


PATIENT #2

Male, age 49
Previously:
Hypertension and type 2 diabetes
Valsartrane and metformin
Emergency response:
pain started 11.05
call to dispatch center 11.20
first BLS unit on site 11.36
12-channel ECG 11.45
call for Medi-Heli 11.28
Medi-Heli attending patient 11.42
thrombolysis started 11.55

Some 50 minutes from onset of continuous pain

transport started 12.25
in hospital 13.05
History:
Was doing wood work outdoors,
sudden onset of chest pain
Findings:
On coach, pale, cold sweat, pulse frequency 80, blood pressure 130/40, oxygen saturation 91%, central chest pain
ECG: sinus rhythm, R-depression, ST-segment elevation II, III, aVF, V5, V6, T-inversion aVR
Pre-hospital diagnosis: AMI
Treatment:
Oxygen by face mask
Ringer infusion 500 ml
Aspirin 250 mg
Metoclopramid 10mg
Morphin 4+2+2 mg
Reteplase 10+10 units
Heparin 5000 units
Nitrate infusion flow dose
Transport:
with ground ambulance
No problems or complications
Feed back
AMI confirmed
Successful thrombolysis


PATIENT #3

Male, age 72
Previously:
History not available
No information available about medication
Emergency response:
pain started 08.30
call to dispach center 08.47
first BLS unit on site 08.52
12-channel ECG 09.29
call for Medi-Heli 09.07
Medi-Heli attending patient 09.18
History
Was connecting a trailer to his car, sudden "attck", followed by fatique and poor general condition
BLS unit requests Medi-Heli to site
Findings
On ambulance stretcher, pale, cold sweat, pulse frquency 65, blood pressure not detectable but radial pulse was present, oxygen saturation 85%
Severe oainin upper abdomen/lower throax, central/facial cyanosis, poor peripheral blood circulation, GCS speech4, eyes 2, mobility 5
ECG: sinus rhythm, ST-segment elevation aVR, ST-segment depression V2-V4
Pre-hospital diagnosis: ruptured aortic aneurysm
Treatment:
Oxygen by face mask
Ringer infusion 500ml + 500ml
Morphin 6+4+10 mg
Transport towards hospital with capacity for vascular surgery
Development:
Conscience level detoriorate further => intubation
Sinus bradycardia => asystole
Patient declared dead 09.50
Feed back from autopsy:
Massive recent AMI


PATIENT #4

Male, age 50
Previously :
Coronary disease, previous AMI 1988, By-passsurgery 1990
Obesity, hyperlipidemia, heavy smoker
Metoprolor, isosorbide nitrate and small dose Aspirin
Emergency response:
pain started 20.00
to regional health care center 20.20
first 12-channel ECG 20.30
call to dispatch center 20.48
transport unit on site 20.51
second 12-channel ECG 21.00
call for Medi-Heli 21.19
Medi-Heli attending patient 21.28
thrombolysis started 21.30

1 hour and 30 minutes from onset of continuous pain

transport started 22.02
in hospital 22.23
History:
To health care center due to chest pain
Pain increased in the center
Findings:
On strecher, pulse frequency 90, blood pressure95/75, oxygen saturation 94%, central chest pain
ECG: sinus rhythm, ST-segment elevation III, aVR, ST-segment depression + T-inversion aVL, V2 - V5
Pre-hospital diagnosis: AMI
Treatment:
Oxygen by face mask
Ringer infusion 500 ml + 500 ml + 500 ml
Aspirin 250 mg
Morphin 4 + 2 + 2 mg
Reteplase 10 + 10 units
Heparin 5000 units
Nitrate infusion low dose
Metoprolol 1 + 1 mg
Transport:
With ground ambulance
No problems or complications
Feed back
Second AMI confirmed
Successful thrombolosis


PATIENT # 5

Male, age 43
Previously:
Thompsen's disease (congenital disorder causing muscular fatique)
November 1996: episode with chest pain and reversible negative T-waves in ECG
At present time no medication
Emergency response:
pain started 12.00
to regional health care center 16.00
first 12-channel ECG 16.19
call to dispatch center 16.42
transport unit on site 17.42

(not available earlier)

second 12-channel ECG 17.02
call for Medi-Heli 16.42
Medi-Heli attending patient 16.50
thrombolysis started 17.20

5 hours and 20 minutes from onset of continuous pain

transport started 17.38
in hospital 17.56
History
sudden onset of chest pain at rest => to regional health care center
Findings
On coach, calm patient, pale, pulse frequency 70,blood pressure 120/80, oxygen saturation 97%, central chest pain
ECG: sinus rhythm, ST-segment elevation III, aVF, ST-segment depression and T-inversion V1-V4
Pre-hospital diagnosis: AMI
Treatment
Oxygen by face mask
Ringer infusion 500 ml
Aspirin 250 ml
Nitrate infusion low dose
Metoclopramid 10 mg
Morphin 4 + 2 + 2 mg
Streptokinase 1,5 million units infusion / 1 hour
Metoprolol 1 mg
Transport
With ground ambulance
No problems or complications
Feed back
AMI confirmed
Successful thrombolysis


PATIENT #6

Male, age 70
Previously:
Coronary artery disease, AMI 1985 and 1997
Metoprolol, enalapril, isosorbide nitrate and warfarin
Emergency response:
call to dispatch center 15.28
first BLS unit on site 15.35
Medi-Heli attending patient 15.38
12-channel ECG 16.10
thrombolysis started 16.16

Some 47 minutes from cardiac arrest due to VF

transport started 16.20
in hospital 16.35
History
In a bus on his way home from the airport after spending 9 days in China
Flight Beijing - Helsinki 9 hours
Sudden gasping and unconsciousness => immediate call to alarm center
Findings:
Collapsed in bus seat, VF
ECG: sinus rhythm, ST-segment elevation V2 - V4
Pre-hospital diagnosis: Cardiac arrest due to VF caused by AMI
Treatment:
DC x 5 => ROSC 15.47
Intubation
Ringer infusion 500 ml
Reteplace 10 + 10 units
Heparin 5000 units
Transport
With ground ambulance
No problems or complication
Feed back:
AMI confirmed
Successful thrombolysis
Pneumonia
Slow recovery of brain condition

Application: Cardiac Arrest

The table shows the distribution of response times for cardiac arrest patients in Staffordshire, UK, in one year, 1998/9.

Response time / Number of cardiac calls
0 to 1 / 11
1 to 2 / 62
2 to 3 / 89
3 to 4 / 171
4 to 5 / 164
5 to 6 / 187
6 to 7 / 198
7 to 8 / 176
8 to 9 / 189
9 to 10 / 98
10 to 11 / 63
11 to 12 / 52
12 to 13 / 32
13 to 14 / 18
14 to 15 / 17
15 to 16 / 15
16 to 17 / 16
17 to 18 / 7
18 to 19 / 4
19 to 20 / 5
20 to 21 / 1
21 to 22 / 1
22 to 23 / 1
23 to 24 / 1
Total 1578

There were 1572 patients taken to hospital with cardiac arrest.

168 of these were alive on reaching hospital. (This is 10.6% of patients.)

150 survived and were discharged. (This is 8.9 of patients.)

We wish to find out how many additional patients would have survived if there had been one

additional ambulance on duty at all times.

We assume that an additional ambulance will cut 10 seconds from response time. This is slightly higher than our estimate for Surrey, because Staffordshire is a slightly smaller ambulance service fewer ambulances, and there is a scale effect.

There are two ways of proceeding.

Method 1.

This assumes that we know which patients survive, and we know the associated response times.

Then we can graph the survival curve


Graph 1.

We now draw a line of best fit for this graph.

Now we say: if we had an additional ambulance, we will on average arrive 10 seconds quicker.

So, on the graph, the response that previously too, say, 4 minutes now has the survival rate of the response that previously took 3 minutes and 50 seconds.

Graph 2.


By considering various points such as this, we can draw in the new survival curve.

The area under the curve represents the total number of expected survivors. The area under the new curve is obviously larger than the one under the old curve, and so represents lives saved.

However, I do not have this data at the moment. If any of you have such data, you could do the exercise for your own service.

In the absence of data about the survival of each patient by response time, we undertake a slightly more circuitous method od analysis.

Method 2.

For this method, we do not need to know which patients survive. All we know is that 168 patients did so. We also need to assume a survival curve. The curve we have found in the cardiac literature appears to be an "artist's impression" of the distribution of survival by time of defibrillation. (Not response time, which will be lower.)

From this curve we read off that 75% of cardiac arrest patients survive if defibbed in 0 to 1 minutes, 60% if defibbed in 1 to 2 minutes, 46% in 2 to 3 minutes, etc. We apply these percentages to the number of patients in our response-time table, and add them up. We find that it gives an estimate of 347 survivors, far more than actual.

Now we say: if ot took an extra minute to defib the patient after arrival, or an extra minute before the ambulance was called, then the 60% figure will now refer to 2 to 3 minutes, not 1 to 2 as above, etc. Adding up all these figures (that is, lagging the previous figures by one minute) leads to an estimate of 276 survivors, still too many.

Supposing that (response time + 2 minutes) equals defib time, we find 221 survivors, (response time + 3 minutes) gives us 178 survivors, and (response time + 4 minutes) gives 145 survivors.

We find that if we lag response time by 3 minutes 17 seconds, we get 168 survivors (which, you recall, is the actuall number alive going into hospital).

If we lag 3 minutes 47 seconds, we get 150 survivors (= number alive OUT of hospital).

So we have consistency between the number of actual survivors, on one hand, and the (lagged response time plus particular form of the survival curve ) on the other.

But now for the real bonus! In that 30 seconds between a lag of 3 mins 17 seconds and 3 mins 47 seconds, an estimated 18 people would have died (168 - 150). That is at the rate of 36 per minute of response time, or 6 people per 10 seconds of response time.

CONCLUSION: An additional ambulance will save an estimated 6 lives a year, for cardiac arrest alone.

The annual cos of an ambulance is £250,000, so the cost per life saved will be about £41,000 or £42,000. (This, of course, says that an ambulance will do nothing else, or, perhaps, that it does nothing else that is worthwhile!)

How long will a cardiac arrest survivor live, on average? If it is 1 year, the cost per life year added will be £42,000. If it is 2 years, it will be £21000; if 3 years, £14000.

I have not looked hard for figures of length of survival. If you know about them, then I would like to hear from you. My belief is that the mean length of survival is quite high, so the cost of saving these lives will be correspondingly low.

So you see that the methodology developed here can be very useful. If it is developed further, the methods will be able to tell policy makers and pokiticians how much should be spent on ambulances, and give you a framework for evaluating your own ambulance service.


Graph 1
Graph 2
 Eesti Kiirabi Liit, Riia 18, 51010 Tartu, EE672200221005141882 ekl@kiirabi.ee