“There are an estimated 268,000 episodes of acute myocardial infarction in the UK each year, 92,000 occurring in men and women under 65years of age” (British Heart Foundation 2004).
The initial symptoms of MI can present as severe or persistent chest pain, Dyspnea (labored or difficulty breathing), pallor (abnormal paleness of the skin), fear, sweating, anxiety, peripheral vasoconstriction, and shock. (Medical Clinical Guidelines 2006). The National Heart and Lung Institute (2007) state that Cardiogenic shock is a state in which a weakened heart isn’t able to pump enough blood to meet the body’s needs. The most common cause of shock is damage to the heart muscle from a severe MI.
Typically, the pain of acute MI is severe and constant, the pain can begin in the chest or in the back, the pain may not last long or it can last for more than 15minutes. The pain may radiate to the throat, jaw, neck, shoulders and arms. The pain can sometimes start in the epigastric region, which could be mistaken for an abdominal problem. Some people may mistake the pain of an MI for indigestion; with an MI the rhythm of the heart can be disturbed (T.E.OH 1997). In patients who are elderly or suffer with diabetes mellitus, MI can be painless (Epstein et al 1999). This is because “diabetes can damage the nerves to the heart and the symptoms of MI may not be felt in the usual way therefore this leads to delays and difficulties in diagnosing MI” (British Heart Foundation 2007). The door to needle time is important in the hospital setting, as it requires prompt assessment of patients presenting with chest pain to identify those with STEMI and commencement of thrombolysis within 20mins of arrival. The greatest improvements in mortality can be gained from call to needle time within 6o minutes of calling for help (DOH 2000) The National Service Framework states that the interval between patients arrival and commencement of thrombolytic therapy (door to needle time) should be <20 minutes. Time delay means muscle loss (Medical Clinical Guidelines 2006)
When a patient is having a suspected MI the aim of care is to limit the infarction size, re-establish an optimal cardiac output, relieve pain and detect and prevent any life-threatening complications. It is important to assess is whether the patient’s airway is patent or occluded. Oxygen therapy should be commenced as early as possible in an attempt to limit myocardial damage and to relieve pain (Opie 1994).
Airway; It is important to observe a patients physiological status, if a nurse comes across a patient and observes that they are short of breath, or their breathing is laboured, if the patient is cold and clammy, and cyanosed or unconscious she would check their airway she can do this by performing the head chin tilt and check that they are breathing if they are she would put them in the recovery position. If the patient was conscious and lying down she would assess whether they can sit up unaided if they couldn’t she would ask for assistance and sit them up using the correct manual handling technique.
The nurse would ask the patient if they had any pain, if they complained of chest pain the nurse would ask the patient how long had they had the pain, does it radiate anywhere and how severe is the pain on a scale of 0 to 3, 0 being no pain, 1 mild pain, 2 moderate pain and 3 severe pain, is there any exacerbating or relieving factors, what does the pain feel like e.g. ,sharp, stabbing, dull etc, how frequent is the pain and are there any other symptoms (Roper, Logan, et al 2002). She could ask another member of staff to check the patient’s notes to see if they had a previous MI or if the patient is able to answer she would ask the patient themselves. “Medical history of a coronary heart disease or had a previous MI, previous medical history can also suggest alternative causes of chest pain” (Antman et al 2000). If MI is suspected, Glyceryl Trinitrate (GTN) will be administered this can be taken sub-lingual (under the tongue) in tablet form, it also comes in a spray, it acts by causing venous and coronary dilatation, this helps to reduce preload, and a reduction in after load, therefore allowing blood to flow with less effort from the myocardium which in turn increases the amount of oxygen to the heart and decreases chest pain (Khan 1998).If the pain does not subside then Diamorphine will be administered, this is an is an opiate the initial dose is 1 to 10mg IV at a rate of 1mg per minute until the pain is relieved, the dose is reduced or stopped if toxicity is observed, e.g. depression of respiration, hypotension or vomiting. The drug relieves anxiety, pain, it causes vasodilatation so therefore reduces preload. The nurse is always assessing the patient’s physiological status as well monitoring their observations. Simvastatin 40mg may be given initially, then orally at night, this helps to reduce cholesterol in the blood (British Nurses Foundation 2006). High flow oxygen (O2) 40-60% via the face mask is administered; if the patient is on continual O2 then it would have to be humidified. If a patient suffers with COPD (Chronic Obstructive Pulmonary Disease) the nurse should be cautious in administering O2 they should have 24% as patients with COPD can retain O2. O2 therapy would be used because if the patient was having an MI as their heart would not be receiving the correct blood flow around the body; therefore if the blood supply is not adequate then the O2 would not be as the blood carries O2 around the body. 300mg Aspirin is administered this is an anti coagulant the patient is asked to chew, macerate and swallow. Aspirin reduces the stickiness of platelets in the blood, which helps to prevent blood clots from forming. It will also be given daily as a preventative to help reduce the risk of an MI in the future (Medical Clinical Guidelines 2006).
Breathing, With MI the patients breathing is usually laboured, the nurse will monitor the patient’s respiratory rate normal respiratory rate is 8-14 breaths per minute tachypnea (rapid breathing) or dyspnoea (laboured or difficulty breathing) will usually be evident. This can indicate levels of hypoxia (deficiency of oxygen) and the onset of pulmonary oedema (accumulation of fluid in the alveoli of the lungs). Heart rate, normal range is 60-100 beats per minute; predominately the patient will be tachycardic (heart rate over 100 beats per minute.) as a response to the decreased cardiac output, the nurse should take into account that the patient is anxious and this can also cause tachycardia due to the sympathetic response. The nurse should also be aware of specific side effects of infarction as bradycardia (low heart rate under 60 beats per minute.) can be associated with inferior infarction. Blood pressure (BP), there is no fixed dividing line between normal blood pressure and a slightly raised blood pressure. Although the British Hypertension society suggests that the ideal blood pressure is 120-80, normal is less than 130-80 and a high normal is 130-80 to 139-89 (British Heart Foundation 2007); in the majority of cases of MI the BP is usually low, this is caused by poor ventricular function and a reduced cardiac output. Oxygen saturation (02), normal range is 95% -100% when the patient is having an MI O2 therapy is vital to ensure the myocardium is receiving as much O2 as possible as discussed on pg 5. Temperature the normal range is 36.0c-37.9c, this can sometimes be forgotten, but in MI a mild pyrexia (37.5) can be indicative of muscle damage due to an inflammatory response (Woods et al 1995).The nurse will repeat this procedure constantly, by doing this she can determine whether the patient is deteriorating. The patient’s heart rate and blood pressure are often within normal range but the pulse rate can vary from a bradycardia to tachycardia which has been discussed.
With a more severe MI signs of heart failure and shock may be observed see pg 3. Auscultation (listening to the heart with a stethoscope) of the heart may be normal, but a fourth heart sound is common, if a third heart sound is heard then this usually indicates a large MI with extensive muscle damage (T.E.OH 1997).
Circulation, If MI is suspected then certain tests will be performed. The12 lead electrocardiogram, bloods will be taken such as Troponine T (Trop T), U&E, FBC, Cardiac enzymes and possibly INR. The ECG and Trop T are the most important. The (ECG) is the most widely used diagnostic tool. An EGG is not an invasive procedure and it is not painful, it is an assessment of the cardiac rhythm that shows ischemic changes or other abnormalities during the testing period. The ECG is used to diagnose diseases of the heart, once a diagnosis is made then treatment can be commenced, it can also be used to detect some pulmonary conditions such as pulmonary embolism. The ECG is less important than the history and physical examination of the patient, as the ECG can read as normal in the first few hours of an MI. After a few hours their may be ST elevation (STEMI) if the ECG shows STEMI thrombolytic therapy should be commenced. The development of a Q wave will become apparent, The ST segment returns to baseline and the T waves become inverted. The leads that show changes in an MI depend on the part of the heart that is affected (Hampton J 2003).
The diagnosis of MI also depends on the measurement of biochemical markers of cardiac muscle damage especially troponins; a rise in troponine 1 or Trop T levels in a patient whom is suspected to have had an MI is now taken to mean that an infarction has occurred, but the treatment still depend on the results of the ECG. (J.R.Hampton 2003) (S.Vanriper, J.Vanriper 1997). Research has shown that the proteins that help to regulate the heart muscle contraction can be isolated in the serum and it is an indicator of MI. The troponine protein consists of three separate proteins, these are Trop 1, Trop T, and Trop C, each of these have a different function. If a patient has had an MI, the Trop T rises in the serum and correlates with the amount of tissue damage. Trop T is measurable within 4 hours of onset of an MI, and then it peaks at approximately 72hours. It is still detectable in the blood for up to 14 days (J.R.Hampton 2003) (S.Vanriper, J.Vanriper 1997).
If the tests come back as a definite MI the medication that may be given is Atenolol 5mg IV or 50mg orally daily, this is a beta blocker used to treat angina, hypertension. It works by slowing the heart rate and helps to reduce the risk of abnormal heart rhythms developing (Medical Clinical guidelines).
Thrombolytic therapy should start as soon as STEMI has been diagnosed and the condra- indications excluded.
Disability, if the patient has severe chest pain then, communicating with the patient and their family is essential. It is important to keep them informed of what is happening as they will be feeling scared, the patient will be having numerous investigations and have cardiac monitors attached to them, and the patient will want to feel reassured by the nurse. “The National Institute for Health and Clinical Excellence guidelines state that; Good communication between healthcare professionals and patients is essential. Families and carers should have the opportunity to be involved in decisions about the patients care and treatment, if the patient agrees to this. Families and carers should also be given the information and support they need.”(NICE 2007).
Exposure the nurse will be assessing the patient’s pressure areas and looking for changes in the skin tone. She will be observing the patient from top to toe looking for bruising of an unusual nature, any rashes and repeating the A, B, C, D, and E, method constantly, while observing the patient’s physiological and psychological status whilst maintaining the patient’s privacy and dignity as much as possible. .
MI has a significant impact on the patient affected and their families. Using the patients’ history, clinical examinations, ECG findings and Trop T, levels a diagnosis can be made and patient risk can be stratified. Nurses have an important role to play in the acute presentation and ongoing hospitalisation phase discharge and long-term management of patients with MI (Coady E 2006)
What has been shown is how significant the nurse’s role is in assessment of a patient, it is usually the nurse who first notices the changes in patient status whether it be physical appearance or the clinical evidence. She is the one who decides when to consult the practitioners and she is the one who keeps the professionals, the patient and the relatives updated and reassured as well as carrying out various procedures.
2650 words
REFERENCES:
Antman EM, Cohen M, Bernink PJ et al (2000) The TIMI risk score for unstable angina/non- ST elevation MI: a method for prognostication and therapeutic decision making. Journal of the American Medical Association. 284, 7, 835-842.
Blatchford O, Capewell S (1997): Emergency medical admissions taking stock and planning for winter. British Medical Journal. 315, 7119, 1322-1323.
Brieger D, Eagle K.A, Goodman S.G et al (2004). Acute Coronary Syndromes without chest pain: insight from the Global Registry of acute coronary events. Chest. 126, 2, 461-469.
British Heart Foundation (2004) Coronary Heart Disease Statistics Database. accessed on 21/10/07.
British Heart Foundation (2007) Coronary Heart Disease. accessed on 28/1/08.
Capewell S, McMurray J (2000) “Chest Pain- please admit”: is there an alternative? A rapid cardiological assessment service may prevent unnecessary admissions. British Medical Journal. 320, 7240, 951-952.
Codey E (2006) Managing patients with non ST- segment elevation acute coronary syndrome. Nursing Standard. 20, 37, 56. pg56
Medical Clinical Guidelines (2006) Acute Myocardial Infarction.
Department of Health (2000) National Service Framework for Coronary Heart Disease. The Stationary Office, London.
Epstein O et al (1999) Clinical Examination. Second edition. London, Mosby.
Fox KA (2004) Management of acute coronary syndromes: an update. Heart. 90, 6,698-706.
Hampton, J.R (2003). The ECG in practice. Fourth edition. Churchill Livingstone, London.
Khan, M.G (1998). Manual of Cardiac Drug Therapy. Second edition. London: Belliere Tindall.
McCance K, Huether S (1998) Pathophysiology: The Biological Basis for Diseases in Adults and Children. Third edition. St Louise, Mosby.
The National Institute of Clinical Excellence (2007) Myocardial Infarction guidelines.
The National Heart and Lung Institute (2007) Cardiogenic Shock. . accessed on 28/1/08.
OH, T.E (1997) Intensive Care Manual. 4th ed, Butterworth-Heinemann: Oxford. Pg 43.
Opie, L (1994) Drugs and the Heart, 2nd ed.London : Saunders.
Patient UK (2007) Myocardial infarction, accessed on 21/9/07.
Quinn, T (1996) Myocardial Infarction. Nursing Times. Knowledge for Practice Professional Development Unit. 25, 1-4.
Snell R (2000). Clinical Anatomy for Medical Students. Fifth edition. Philadelphia PA, Lippincott, Williams and Wilkins.
Vanriper S, Vanriper J (1997). Cardiac Diagnostic Tests-A Guide for Nurses. London: WB. Saunders.
Woods, S.L, et al (1995). Cardiac Nursing. Third edition. Philadelphia: JB Lippincott.
