Category: Critical Care Nursing Although detectable troponin levels usually emanate from myocardial cells, they may not always represent irreversible cell death or myocardial ischemia. Renal dysfunction is another factor associated with elevated troponin levels.
Category: Critical Care Nursing Troponin release in the critically ill may not always represent myocardial cell death. Endotoxin, cytokines and inflammatory mediators, along with catecholamines and conditions such as hypotension or hypoxia, may cause the breakdown of troponin.
Category: Critical Care Nursing Demand ischemia (type 2 MI) can also lead to troponin release. Other causes of elevated troponin include sustained brady-/tachy-arrhythmias, hypotension, shock, cardiomyopathy, sepsis, pulmonary embolism and strenuous exercise.
Category: Critical Care Nursing The challenge for the clinician, and particularly for the intensivist, is that although the elevation of serum troponin is highly specific for myocardial cell damage, not all of the damage is a consequence of the rupture of an atherosclerotic plaque.
Category: Critical Care Nursing Troponin elevations are sensitive and specific for myocardial cellular injury. False positives because of fibrin interference or antibodies are infrequent. Even minor increases in troponin values correlate with adverse outcomes in NSTE-ACS.
Category: Critical Care Nursing Creatine kinase (CK) and its isoenzyme MB (CK-MB) were the initial biomarkers of choice for myocardial injury and infarction in the 1970s, but were later superseded by troponin T and I, because of their increased sensitivity and specificity.
Category: Critical Care Nursing With cardiac cell death, proteins are released into the blood and detection of these proteins has played a key role in establishing the diagnosis of ACS, predicting its outcome and directing treatment.
Category: Critical Care Nursing “Nondiagnostic” ECGs are common in the setting of true acute MI, characterizing up to 8% of such patients. Nondiagnostic ECG findings may be due to occlusion of small vessels or insensitivity of the ECG in lateral or posterior myocardial territory.
Category: Critical Care Nursing Preexcitation, bundle branch block, pericarditis, pulmonary embolism, subarachnoid hemorrhage, metabolic disturbances and left ventricular aneurysms can be associated with ST elevation in the absence of acute myocardial ischemia.
Category: Critical Care Nursing Acute coronary syndromes (ACSs) are a group of conditions characterized by acute myocardial ischemia resulting from inadequacy of myocardial blood flow. The ACSs are classified by clinical, biochemical and electrocardiographic data.
Category: Critical Care Nursing Type 4C myocardial infarction is associated with percutaneous coronary intervention restenosis, while type 5 myocardial infarction is associated with CABG (≤48 hours after the procedure).
Category: Critical Care Nursing Type 4A myocardial infarction is associated with percutaneous coronary intervention (≤48 hours after the procedure), while type 4B myocardial infarction is a stent/scaffold thrombosis associated with percutaneous coronary intervention.
Category: Critical Care Nursing Type 3 myocardial infarction involves the cardiac death in patients with symptoms suggestive of myocardial ischemia and presumed new ischemic ECG changes before cardiac troponin (cTn) values become available or are abnormal.
Category: Critical Care Nursing A type 1 myocardial infarction is caused by atherothrombotic coronary artery diseases, while a type 2 myocardial infarction is caused by myocardial injury in the context of a mismatch between oxygen supply and demand.
Category: Critical Care Nursing In pericarditis, pericardiocentesis is performed for therapeutic purposes in the case of tamponade and for diagnostic purposes if tuberculosis, bacterial infection or malignancy is suspected.
