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					   Pre-Hospital Management of
           Chest Pain
Roll of the EMS System in Reducing Morbidity & Mortality
             from Acute Coronary Syndromes

                     June 25, 2007

            Andrew D. McGuire, BS, EMT-P
                  EMS Coordinator
Outline
• Anatomy & Physiology
• ACS Risk Factors
• Pathology
   – Angina
   – Myocardial Infarction
• DH ACS Protocol
• 12-Lead ECG
Thoracic Cavity
Heart Walls and Chambers
The Heart
            •   Four Chamber Pump
            •   Blood fed into RA
            •   From RV to Lungs
            •   Back to LA
            •   To Body from LV
                through Aorta
Coronary Arteries
• Heart Muscle fed by
  Coronary Arteries
• Originate from base of
  Aorta
• LCA
   – LAD: Ant LV & septum
   – LCA: Post LV
• RCA: RA & RV
Electrical Impulses
Physiology

• Pump
   – Diastole
   – Atrial Systole
   – Ventricular Systole
• Pressure
   – Starling’s Law
Risk Factors

•   High blood Pressure
•   Diabetes
•   High Cholesterol
•   Immediate Family History (age < 55-60)
•   Smoking
•   Gender: Males > Females
•   Cocaine Use
Atherosclerosis
                          Pathology of Acute
                               Coronary
                          Syndrome (what is
                          a heart attack, also
                             called “ACS”)


                              From the pre
                          clinical phase to the
                             acute phase of
                               myocardial
                                infarction




From the AHA/ACC STEMI guidelines
Pathology
•   Atherosclerosis
•   Thrombus/Emboli
•   Trauma
•   Spasm
•   Low/No Oxygen
     – Anemia
     – Hypotension
     – Drugs/toxins (CO, cocaine, opiates, cyanide)
     – Hypoxia
Angina

• Pathophysiology
   – Ischemia of heart muscle due to
     inadequate oxygen supply
      • Causes may include partial occlusion,
        spasm, hypotension and anemia
   – Transient in nature
Angina

• Stable: Onset during physical activity, lasting
  3 to 5 minutes, relief with rest or self
  administered nitrates.
• Unstable: Onset at rest, occurring more
  frequently, lasting > 5 minutes, resistance to
  nitrates.
Angina

• Signs and Symptoms
   – Chest Pain/ Pressure
   – Dyspnea
   – Diaphoresis
   – History is Essential
Acute Coronary Syndrome / Myocardial
Infarction
    ACS / Myocardial Infarction
•   Pathophysiology
     – Death and necrosis of
       heart muscle due to
       inadequate oxygen
       supply.
        • Causes may include
          occlusion, spasm,
          microemboli, acute
          volume overload,
          hypotension, acute
          respiratory failure, and
          trauma.
     – Location and size
       dependent on the vessel
       involved.
ACS / Myocardial Infarction
 – Effects of a Myocardial Infarction
    • Dysrhythmias
    • Heart Failure
 – Goals of Treatment
    • Pain Relief
    • Reperfusion
        TIME = MUSCLE
Prevalence of heart attack
• Two types of heart attacks
   – STEMI – or ST elevation myocardial infarction
   – NSTEMI – or non-ST elevation myocardial infarction
• 0.5 million STEMI’s a year in United States
• About 100 per year at Danbury Hospital ED
• Mortality from STEMI has been decreasing
   – Roll of public education – early presentation
• Incidence of STEMI decreasing but NSTEMI increasing
   – Roll of public education – early presentation
Prevalence of heart attack declining
• Overall reduction from
   – Aggressive treatment of diabetes
   – Aggressive treatment of lipid disorders
   – Aggressive treatment of hypertension
   – Smoking cessation programs and public pressure for
     a smoke free environment
Facts about ACS presentation
• 30 percent of patients present with a lethal arrhythmia
• 1 in 300 will fibrillate in the ambulance
• Over 50% of acute myocardial infarctions DO NOT take an
  ambulance to the hospital – but chose to travel by private
  car instead
• Taking an aspirin for symptoms has been associated with
  a delay in therapy – patients should be instructed to call
  911 instead.
• The average delay from symptoms to calling 911 is two
  hours
Common Presenting Symptoms
•   Chest pressure or discomfort
•   Shoulder, neck, arm or jaw pain
•   Dyspnea
•   Syncope
•   Palpitations
•   Diaphoresis
•   Nausea
•   Anxiety
Essential Elements of the History
• Specific location of the chest pain (midsternal, etc.)
• Radiation of pain, if present (e.g., to the jaw, back, or
  shoulders)
• Duration of the pain
• Factors that precipitated the pain (exercise, stress, etc.)
• Type or quality of the pain (dull or sharp)
• Pain scale (1-10)
• Associated symptoms (nausea, dyspnea)
• Anything that worsens, intensifies or alleviates the pain
  (including medications, moving or a deep breath)
• Previous episodes of a similar pain (e.g., angina)
Items of Immediate Assessment (<10 min)
•   Check vital signs
•   Determine oxygen saturation
•   Obtain 12-lead ECG (Paramedic)
•   Obtain a brief, targeted history and
    perform a physical examination
Immediate General Treatment
(AHA Guidelines)
• Oxygen at 4 L/min
• Aspirin 160 to 325 mg
• IV of Normal Saline (EMT-I or P)
• Nitroglycerin SL or spray (EMT-P)
   – EMT-B may assist with patients NTG
• Morphine IV (if pain not relieved
  with nitroglycerin) (EMT-P)
Oxygen Used in
Acute Coronary Syndromes
Why?
• Increases supply of oxygen to ischemic tissue
When?
• Always when AMI is suspected
How?
• Start with nasal cannula at 4 L/min
• Increase to NRB 10-15 LPM as needed
Watch Out!
• Rarely COPD patients with hypoxic
   ventilatory drive will hypoventilate
• Administer O2 despite normal pulse-ox readings!
Aspirin: Actions
Why? (Actions)
  – Blocks formation of thromboxane A2
    (thromboxane A2 causes platelets to
    aggregate and arteries to constrict)
These actions will reduce
   – Overall mortality from AMI
   – Nonfatal reinfarction
   – Nonfatal stroke
Aspirin
• Mechanism of Action:
  Aspirin inhibits platelet aggregation, blocks pain impulses in
  the CNS.


• Onset and Duration:
  Onset:      15 to 30 minutes
  Duration:   4 to 6 hours
Aspirin:
Indications, Dose, Precautions
When? (Indications) As soon as possible!
   – Standard therapy for all patients with new pain
     suggestive of AMI
   – Give within minutes of arrival
How? (Dose) (4) 81 mg tablets taken as soon as possible
Watch Out! (Precautions)
   – Relatively contraindicated in patients with active peptic
     ulcer disease, asthma or on Coumadin therapy
   – Contraindicated in patients with known aspirin
     hypersensitivity
   – Bleeding disorders
Pre-Hospital ACS Protocol
1. Primary BLS Level Care
   a. Initial assessment
   b. Oxygen, Vital signs, SpO2 monitoring

2. Aspirin (ASA):
   a. (4) 81 mg tabs Baby ASA PO
   b. Do not give ASA if the patient:
         i. Has a known allergy to ASA
         ii. Took 324 mg of ASA within last 8 Hours
Pre-Hospital ACS Protocol
  If suspected STEMI/12-Lead ECG
  transmitted, identify the call to the
  ED as a “Cardiac Alert” – report to
  the ED physician (same as Trauma
            Alert protocol)
Aspirin / Chest Pain
 Documentation of aspirin must be done by the EMT/EMT-I who
 administered it. The following must be documented on the
 PCR, in addition to the normal information and data:

  –   Time and dose administered
  –   Route of administration
  –   EMT administering the ASA
  –   Problems or complications (i.e. vomiting)
  –   Response, if any, to the treatment
  –   Vital signs after administration

 This data needs to be documented on the paramedic intercept
              PCR as well as the primary responder.
Key Issue – the 12 lead ECG
• A normal tracing does not preclude a heart attack
• Use of primary angioplasty or thrombolytic therapy is
  restricted to patients with STEMI and typical symptoms of
  heart attack
   – Thus the 12 lead is critical for determining acute
     therapy
   – Obtaining a 12 lead electrocardiogram in the field and
     transmitting it to medical control reduces the time of
     delivery for urgent care
12 Lead ECG examples
STEMI = 1 mm ST elevation in limb leads or 2 mm elevation in precordial leads

               limb leads                   precordial leads




                       No acute changes – not STEMI
                             could be NSTEMI
STEMI = 1 mm ST elevation in limb leads or 2 mm elevation in precordial leads

               limb leads                     precordial leads




                        Acute changes – Anterior STEMI
STEMI = 1 mm ST elevation in limb leads or 2 mm elevation in precordial leads

               limb leads                     precordial leads




                       Acute T wave changes – not STEMI
                                could be NSTEMI
STEMI = 1 mm ST elevation in limb leads or 2 mm elevation in precordial leads

               limb leads                      precordial leads




                         Acute changes – Inferior STEMI
STEMI = 1 mm ST elevation in limb leads or 2 mm elevation in precordial leads

               limb leads                      precordial leads




                         Acute changes – Inferior STEMI
ST Elevation in Leads II, III & aVF – Inferior Wall MI!
In the treatment of Heart Attack the
Goal is a Door to Balloon Time of less
then 90 minutes
• Each year, nearly 400,000 patients have ST-
  elevation myocardial infarction
• Many patients are treated with emergency
  angioplasty
• Recent national guidelines set a goal of door-to-
  balloon time of less than 90 minutes in 75 % of
  the time
                                    Where are we,
                                     where do we
                                    want to be, and
                                    what can we do
                                     to get there?




From the AHA/ACC STEMI guidelines
In the treatment of Heart Attack less
time means lives saved

                               Longer delay
                               times means
                               higher in
                               hospital
                               mortality.

                               NRMI-2 data. from
                               Cannon et al, JAMA
                               283(22); 2941
How the time is used to get to 90 minutes

                                                                                     Seen by MD to                                 Ready for
                                                                                     complete care                                 Transfer to
                                            Seen by MD                                                                             Cath. Lab
Pt arrives to                                                 Call back from
                   EKG to MD              then call placed
ED to EKG                                    to PAMD              PAMD
                                                                                                            30 minutes

          15 minutes                                 5 minutes                                   Cath Called by MD to All Cath Ready



                                                                                                           30 minutes

                                                                                                                         • Cath Team
                                                                                                                           responds to call


                                                                               • Transportation between
                                                    • Informed                   ED and Unit
                       • Procedure                    Consent                  • Service Elevator

                                                                               Leaves ED to
                       Stick to Balloon              Cath Arrival to
                                                                               Patient Arrives
                             Time                     Stick Time
                                                                                to Cath Lab


                        15 minutes                     20 minutes                5 minutes
How to shorten Door to Balloon Time –
Remote ECG Transmission
                                  Seen by MD
 Pt arrives to                                     Call back from
                    EKG to MD   then call placed
 ED to EKG                         to PAMD             PAMD



           15 minutes                      5 minutes
Danbury Hospital – Plans for therapy
•   Open Heart Surgery – available now
•   Primary Angioplasty – available now
•   Thrombolytic therapy – available now
•   Catheterization and treatment of NSTEMI
    – available now
                             Danbury Hospital D2B time
                Q1 October-Decemeber 2005 vs. Q2 January-March 2006
          100
                                                                      D2B time


          98


          96
minutes




          94


          92
                  N= 15 pts                          N= 14 pts
          90


          88
                      Q1                                 Q2
                12 Lead EKG taken in the field vs. not taken in the field
                        Danbury Hospital Door to Balloon time
          120
                                                                                 113
                                  12 leads in field

                                  12 lead Not obtained in the field
          100
                             92


          80
                                                                      72
minutes




          60     57



          40
                N=4         N=3                                       N=4        N=3
          20



           0
                       Q1                                                   Q2
        ECG transmission from the field saves time
        and lives in real life
bulance EKG Transmission to ED Prior to Arrival

                                      15% of all EKGs were
                                      transmitted from Oct 2005 to
                                      March 2007
   3rdQ: 116.5 min.

                           103 min.
          95.5
                                                                          90 Minute goal
                                 85
                                                          76.25 min.                            30 minutes
                                                                                               saved when
                                                                                                  ECG’s
                                                               56.5                            transmitted
                                                                                              from the field
 n=50                   n=43                          n=8
WalkIns                A mb-No                      A mb-Yes
                 Ambulance Transfer           Ambulance Transfer
                  EKG Transmission?
                 No ECG transmission           ECG transmission

                                                            First 99 AMI treated at Danbury
Summary
•   50% of ACS patients still self-referring to the ED
•   Public education on role of 911 system still needed
•   More aggressive ASA administration by EMS
•   12-Lead ECG & Transmit to the ED when STEMI identified
•   Patch in as a “Cardiac Alert”

    In a short period of time, we have demonstrated how
      our role in the pre-hospital setting is having a direct
         impact in the outcome (decreased morbidity &
       mortality) of ACS patients in the Greater Danbury
                               Area.

				
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