B P5 C38 ST Elevation Myocardial Infarction: Management Flashcards
Major components of the time from the onset of ischemic symptoms to reperfusion include:
(1) Time for the patient to recognize the problem and seek medical attention
(2) Prehospital evaluation, treatment, and transportation
(3) Time for diagnostic measures and initiation of treatment in the hospital (e.g., “door-to-device” time for patients undergoing a catheter-based reperfusion strategy and “door-to-needle” time for patients receiving a fibrinolytic agent);
(4) the time from initiation of treatment to restoration of flow.
Most deaths associated with STEMI occur within the first hour of its onset and usually result from _____.
Ventricular fibrillation (VF)
Patient-related factors that correlate with a longer delay until deciding to seek medical attention include:
Older age
Female sex
Black race
Low socioeconomic or uninsured status
History of angina, diabetes, or both
Consulting a spouse or other relative
Consulting a physician
Patients should also be instructed in the proper use of sublingual nitroglycerin and to call emergency services if the ischemic-type discomfort persists for more than _____ minutes.
> 5 minutes
EMS systems have three major components:
Emergency medical dispatch
First response
EMS ambulance response
Patients with STEMI who presented within 3 hours of symptom onset and could not undergo primary PCI within 1 hour were randomized to fibrinolysis and coronary angiography within 6 to 24 hours (n = 944) versus primary PCI (n = 948).
The primary endpoint of death, shock, heart failure, or reinfarction at 30 days occurred in 12.4% of the fibrinolysis arm and 14.3% in the primary PCI arm (p = 0.21). Prehospital fibrinolysis is reasonable in settings in which substantial time can be saved by prehospital treatment because of long transportation times (60 to 90 minutes or longer)
STREAM (Strategic Reperfusion Early After Myocardial Infarction)
Half dose of tenecteplase has similar efficacy and lower rates of ICH in patients >75 years old
Interventions to Improve Door-to-Device Times
- A prehospital ECG for diagnosing STEMI is used to activate the PCI team while the patient is en route to the hospital.
- Emergency physicians activate the PCI team.
- A single call to a central page operator activates the PCI team.
- A goal is set for the PCI team to arrive at the catheterization laboratory within 20 min after being paged.
- Timely data feedback and analysis are provided to members of the STEMI care team.
Efforts to shorten the time until treatment of patients with STEMI include:
(1) Improvement in the medical dispatch component by expanding 911 coverage
(2) Providing AED to first responders
(3) Placing AED in critical public locations
(4) Greater coordination of the EMS ambulance response
Multiple observational studies and several randomized trials have evaluated the potential benefits of prehospital versus in-hospital fibrinolysis. Although none of the individual trials showed a significant reduction in mortality with prehospital-initiated fibrinolytic therapy, earlier treatment generally provides greater benefit, and a meta-analysis of all the available trials demonstrated a ___% reduction in mortality
17%
EMS to needle time: __________
Door to needle time: __________
Dood to device time: __________
FMC to device: __________
Total Ischemic time: __________
EMS to needle < 30 mins
Door to needle < 30mins
Door to device < 90mins
FMC to device: < 120 mins
Total ischemic time < 120mins
A history of _____ and the ______ are the primary tools for screening patients with possible acute coronary syndrome (ACS) for STEMI
Ischemic-type discomfort
Initial 12-lead ECG
_________ should be obtained promptly (≤10 minutes after hospital arrival)
ECG
Critical factors that weigh into selection of a reperfusion strategy include the ____.
(1) Time elapsed since the onset of symptom
(2) Risk associated with STEMI
(3) Time required to initiate an invasive strategy
(4) If that time is expected to be prolonged, the risk related to administering a fibrinolytic
Patients with an initial ECG that reveals ST-segment depression and/or T wave inversion without ST-segment elevation are not considered candidates for immediate reperfusion therapy unless a _____ injury current is suspected
Posterior (or inferobasal)
ABSOLUTE Contraindications in the use of Fibrinolytics in STEMI
- Any previous intracranial hemorrhage
- Structural cerebral vascular lesion (e.g., AVM)
- Malignant intracranial neoplasm (primary or metastatic)
- Ischemic stroke within 3 months except acute ischemic stroke within 4.5 hr
- Suspected aortic dissection
- Active bleeding or bleeding diathesis (excluding menses)
- Significant closed-head or facial trauma within 3 months
- Intracranial or intraspinal surgery within 2 months
- Severe uncontrolled hypertension (unresponsive to emergency therapy)
- For streptokinase, previous treatment within the previous 6 months
RELATIVE Contraindications in the use of Fibrinolytics in STEMI
- History of chronic, severe, poorly controlled hypertension
- Significant hypertension at initial evaluation (SBP >180 mm Hg or DBP >110 mm Hg)†
- History of previous ischemic stroke >3 months
- Dementia
- Known intracranial pathology not covered in Absolute Contraindications
- Traumatic or prolonged (>10 min) CPR
- Major surgery (<3 weeks)
- Recent (within 2 to 4 weeks) internal bleeding
- Noncompressible vascular punctures
- Pregnancy
- Active peptic ulcer
- Oral anticoagulant therapy
This should be administered at the first opportunity after initial medical contact; effective across the entire ACS spectrum and is part of the intial management strategy for patients with suspected STEMI.
Aspirin 162-325mg LD
Control of cardiac pain uses a combination of:
Analgesics (e.g., morphine)
Interventions to improve the balance of myocardial oxygen supply and demand, including:
Oxygen (in the setting of hypoxia)
Nitrates
Beta blockers
This remains the analegsic drug of choice except in patients with well documented hypersensitivity
Morphine
4 to 8 mg can be administered intravenously initially, followed by doses of 2 to 8 mg repeated at intervals of 5 to 15 minutes until the pain is relieved or side effects emerge—hypotension, depression of respiration, or vomiting.
Reduction of anxiety with successful analgesia diminishes the patient’s restlessness and the activity of the autonomic nervous system, with a consequent reduction in the heart’s metabolic demands,
Morphine has beneficial effects in patients with pulmonary edema as a result of peripheral arterial and venous dilation (particularly in those with excessive sympathoadrenal activity); it _____ work of breathing.
Reduces the work of breathing
Slows the HR secondary to combined withdrawal of sympathetic tone and augmentation of vagal tone
Maintaining the patient in a _____ if BP falls can minimize hypotension following the administration of nitroglycerin and morphine.
Such positioning is undesirable in patients with pulmonary edema, but morphine rarely produces hypotension in these circumstances.
Supine position and elevating the lower extremities
By virtue of their ability to enhance coronary blood flow by _____ and to decrease ventricular preload by _____, sublingual (SL) nitrates are indicated for most patients with an ACS
Coronary vasodilation
Increasing venous capacitance
IV administration of ____ may be helpful in treating excessive vagomimetic effects of morphine.
Atopine
NTG should not be given are those with
1.
2.
Suspected RV infarction
Marked hypotension (e.g., systolic BP <90 mm Hg), especially if accompanied by bradycardia