ACUTE MYOCARDIAL INFARCTION 1. Assess all patients with chest pain immediately, even if only to check their vital signs and ECG. 2. Immediate 12 leads ECG. 3. Attached to bedside ECG monitor in coronary unit for 48 hours (the at-risk time for cardiac arrest due to ventricular arrhythmia). DIAGNOSIS 1. The diagnosis is made on the history and ECG. 2. Cardiac enzymes (CK, CK-MB and troponins) are unhelpful in deciding whether to thrombolyse; they are a retrospective guide to diagnosis. 3. ECG criteria for thrombolysis are: 2 mm ST elevation in two or more of the chest leads (V1–V6) 1 mm ST elevation in two or more of limb leads (II, III and aVF or I and aVL) New left bundle branch block. MANAGEMENT Take a brief history: type of pain, time of onset, previous episodes of pain, contraindications for thrombolysis, previous thrombolysis, allergies. Examine the patient quickly but include the vital signs (including both arm blood pressures), JVP, heart and lung examinations, all peripheral pulses and O2 saturations. If the diagnosis is clear, your plan should be: 1. Move the patient to the CCU. 2. Cardiac monitor 3. 100% O2 via reservoir mask (caution if COPD) 4. IV access and send bloods for FBC, clotting, U+Es, glucose, lipids, cardiac enzymes. 5. Do a Glucostix. If blood sugar BS > 10, then start an insulin sliding scale even if there is no history of diabetes. 6. 2.5–15 mg IV diamorphine or morphine, with 10 mg IV metoclopromide for pain. Reduces patient restless, anxiety, and relieve lung congestion. Usually combined with antiemetic metoclopramide 10mg IV. Dose 2- 8 mg every 5 – 15 minutes, till improvement or appearance of toxicity. Morphine side-effect: (vomiting, hypotension “usually subside with lower limbs elevation and atropine IV”, respiratory depression, bradycardia,). 2-3 mg\kg of morphine as total dose frequently well tolerated. The antidote of morphine is naloxone IV 0.1-0.2 mg. 7. Other pain killer Meperidine, Pentazocine, Thoracic epidural anaesthesia. 8. 300 mg aspirin orally. Aspirin, forms part of the initial management strategy and should be continued indefinitely, unless contraindicated. Quick blocker of thromboxane A2 in platelets (antiplatelet effect). Immediately after the diagnosis of acute MI a dose of 160 – 325 mg should be given. Better to chew the tablet to promote buccal absorption. Aspirin and thrombolysis therapy have synergistic effect. 9. organize a portable chest X-ray. 10. Nitrate S\L. To decrease ventricular preload, enhance coronary blood flow, Contraindicated in inferior AMI, hypotension, and bradycardia. Long acting nitrate should be avoided in the early course of AMI because they produce haemodynamic changes. IV nitrate can be use for both, persisting cardiac pain and pulmonary edema (if BP allows). 11. Minimizing, myocardial oxygen consumption by: Maintaining the patient at physical, and mental rest. Mild sedation. Quite atmosphere. Use beta blocker to reduce heart rate, unless there is LVF or bradycardia less than 50 beats\ m. 12. Primary PTCA (immediate catheterization and PTCA), mainly if thrombolytic therapy is failed or contraindicated. 13. V Metoprolol a beta antagonist, 5-10mg, particularly if heart rate more than 100\m. All patients should receive beta-blocker therapy, unless contraindicated (such as: COLD, very poor ejection fraction EF…). Withdrawing them after 3 years in low risk cases. 14. All patients with pulmonary oedema and the reduced EF (less than 40%) should receive angiotensin converting enzyme inhibitors (ACE inhibitor). ACE inhibitor should be continued usually for life. 15. Anticoagulation therapy with warfarine is indicated in large anterior Q-wave, usually for 3 months. 16. Ensure there are no contraindications for thrombolysis: active bleeding, e.g. trauma, melaena suspected aortic dissection prolonged resuscitation recent head trauma or suspicion of intracranial haemorrhage pregnancy blood pressure > 200/120; give IV nitrates to reduce blood pressure, then thrombolyse recent major trauma or surgery (e.g. laparotomy within 2 weeks) recent stroke (within 6–8 weeks or previous haemorrhagic stroke) active proliferative diabetic retinopathy – discuss with your seniors. 17. Give either streptokinase (SK) 1.5 mu or tissue plasminogen activator (tPA) or its equivalent – check your local guidelines. 18. Treatment of complications. 19. The 2nd day a gradual mobilization should be started if the patient is pain-free. 20. In non-complicated AMI a discharge can be given on the 6th day. 21. After discharge the patient should be advice for: Exercise testing 24h-Holter monitoring. Coronary angiography in high risk group. Not to drive car for one month. To start his usual work after 2 months, unless his doctor advice him for other instruction. POINTS TO WATCH POST-THROMBOLYSIS Hypotension This might be due to bleeding or to primary cardiogenic shock. Give IV colloid via a large peripheral cannula in case of obvious bleeding. Call for senior advice if no obvious bleeding seen. Get an urgent echo to assess the LV function. Repeat 12-lead ECG. Put in urinary catheter to measure urine hourly. The patient might need a central line or Swan–Ganz catheter plus inotropic support. This is common with streptokinase. Stop the infusion and, if the blood pressure improves, restart at half the rate. If the blood pressure remains low, consider giving tPA. Haemorrhage is an alternative cause of hypotension. Allergic reaction Stop thrombolysis. Give IV chlorpheniramine 10 mg and IV hydrocortisone 100 mg. Reduced consiousness level CS This strongly suggests intracranial bleeding. Stop thrombolysis an urgent CT head is needed. Bleeding Into the gut, urinary tract or from vascular puncture. Stop infusion and give blood and FFP/aprotinin. Get advice from your local haematologist. Points to watch post-MI Pulmonary oedema Give furosemide (frusemide) IV 80 mg. Call senior help. Listen for new murmurs of VSD or acute mitral regurgitation. Get an urgent echo. If not improving, give another 80 mg furosemide (frusemide) IV and start an IV nitrate infusion. Right ventricular infarction Low blood pressure with raised JVP, but the chest is often clear. Do a right-sided ECG and look for ST elevation in V4R; this indicates RV infarction. Give IV fluids, not diuretics in this situation. Try 250 mL of colloid over 15 min. RHYTHM DISTURBANCES Symptomatic bradycardia. Give IV atropine 0.5 mg every 5 min to a maximum of 3 mg total. If still bradycardic, proceed to temporary pacing. Complete heart block. In anterior MI or if symptomatic or haemodynamically compromised, put in a temporary pacing wire; otherwise observe on the CCU. Ventricular tachycardia. Call for senior help. If asymptomatic, give IV amiodarone. If symptomatic, the patient needs immediate cardioversion. Note that accelerated idioventricular rhythm (‘slow VT’) at around 90–120/min is common in the hours after an MI and does not usually require treatment. CHEST PAIN Pericarditis. ECG shows saddling of ST segments. The pain is sharp and worse on leaning forward, lying flat, and on inspiration. Give NSAIDs, e.g. diclofenac 50 mg three times a day. Angina. ECG shows no resolution of ST segments, or re-elevation of ST segments. The patient might need rethrombolysing or urgent angioplasty. Musculoskeletal. Point tenderness on chest – treat with simple analgesia.
Posted on: Fri, 26 Sep 2014 20:39:57 +0000
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