اشتباهات شایع در آی سی یو 12: درد قفسه سینه در بیماران آی سی یو

Be Concerned About Chest Pain Even if it is Found to be Noncardiac in Nature

Laith Altaweel MD

Chest pain in the intensive care unit (ICU) is a common and potentially serious complaint. The differential diagnosis of chest pain is broad, and the physician must not be limited to cardiac etiologies, although myocardial infarction and angina must always be considered. The initial approach to chest pain requires a rapid evaluation, history, physical, electrocardiogram, chest radiograph, and the consideration of additional laboratory and radiologic tests.

The initial approach should be to ensure that the patient has hemodynamic and respiratory stability. This usually results from an assessment of the patient's vital signs and clinical condition. The patient who is bradycardic and hypotensive requires more urgent diagnosis than the patient in pain who is awake and conversant. If the condition is stable, a concise history regarding the nature of the pain should be obtained. A mnemonic that may be helpful in asking the necessary questions is OLDCAAR (Table 316.1). Classic symptoms of myocardial infarction or ischemia include chest pain that may be characterized as sharp, dull, pressure, tearing, or crushing or a feeling of doom. Patients may complain of radiation to the chin, left arm, or back. Associated symptoms may include nausea, vomiting, diaphoresis, and palpitations. The astute clinician should consider atypical symptoms such as “gas†or heartburn to be cardiac in etiology until proven otherwise.

A focused physical exam should be performed looking first for cardiovascular problems such as a difference in the pulses between the limbs, pulses paradoxus, pulse volume and rate, new murmurs, rubs, or gallops. It is important to note that the exam may be normal despite a cardiac etiology. Additional physical signs may provide insight to other etiologies. For example, rhonchi or rales, absent breath sounds, or hyper-resonance may point toward a pulmonary etiology, whereas abdominal tenderness, masses, absent or abnormal abdominal sounds, guarding. and rebound may provide insight into an abdominal component.

 

TABLE 316-1 OLDCAAR MNEMONIC

O: Onset of pain: When? What was the patient doing at the time?

L: Location of pain? Pinpoint or diffuse?

D: Duration of pain, days or seconds? Comes and goes or persists?

C: Character of pain: dull, sharp, lancinating, ripping, tearing, etc.

A: Associated symptoms such as nausea, vomiting, diaphoresis, palpitations

A: Alleviating/aggravating factors such as position, belching, deep breathing

R: Radiating to back, arm, abdomen, neck

Watch Out For

A chest radiograph should be obtained to look for a pneumothorax, widened mediastinum, effusion, new infiltrates, free subdiaphragmatic air, rib fractures, and malpositioned endotracheal, nasogastric, or chest tubes. An electrocardiogram should always be obtained. Changes suggestive of cardiac ischemia or infarction can often be seen as changes in the ST segment, T wave morphology, or the presence of Q waves, which can indicate cardiac ischemia or infarct. Cardiac serum markers such as troponin and creatinine phosphokinase MB can also identify myocardial injury. If the clinical history and ECG suggest cardiac ischemia, the treatment for acute cardiac syndromes should be initiated.

Pulmonary embolism (PE) is a constant concern for ICU patients, many of whom have at least one risk factor, which include immobilization, burns, a hypercoagulable state, and heart failure. PE can present with pleuritic chest pain, tachypnea, and dyspnea. Large PEs can result in cardiovascular collapse with hypotension from obstructive cardiogenic shock. Echocardiogram may reveal a dilated right ventricle with reduced function and a septal shift. The chest radiograph will likely be normal and a computed tomography (CT) angiogram or ventilation/ perfusion scan will be necessary to confirm the clinical suspicion. The treatment for a PE in the setting of hemodynamic stability is anticoagulation.

The symptoms of aortic dissection often overlap with those of myocardial ischemic pain. The sudden onset of severe, sharp chest pain that may or may not radiate to the back is a typical symptom. A chest x-ray is usually not helpful but may reveal a widened mediastinum, the separation of intimal calcification from the aortic knob, the deviation of the trachea, or the blurring of the aortic margins. Comparison with a recent radiograph is helpful. Contrast-enhanced CT is usually the best confirmatory test. The initial management should focus on blood pressure control and be followed by surgical consultation.

A pneumothorax can occur in ICU patients secondary to iatrogenic causes such as central venous catheter placement or ventilator-associated barotrauma. Pulmonary diseases such as chronic obstructive pulmonary disease, asthma, and acute respiratory distress syndrome are risk factors. If a patient with a pneumothorax develops hypotension, jugular venous distension, absence of breath sounds, hyper-resonance to percussion, and tracheal deviation, then the development of a tension pneumothorax is likely. A tension pneumothorax is of special concern for patients on mechanical ventilation receiving positive pressure. Immediate needle decompression and chest tube placement may be life saving in this condition.

Esophageal rupture can also cause chest pain and is a life-threatening condition that can lead to lethal mediastinitis. The history may suggest ingestion of a caustic substance, forceful vomiting, or iatrogenic trauma (e.g., nasogastric tube placement, esophageal dilation). Physical examination may reveal subcutaneous emphysema or mediastinal crackling on auscultation, known as Hamman's crunch. Chest radiograph may show pneumothorax, pneumomediastinum or pneumoperitoneum, pleural effusion, or subcutaneous emphysema. A water-soluble contrast study or esophagoscopy confirms the diagnosis.

Intravenous contrast-enhanced spiral computed tomography can be helpful in evaluating for many of these conditions within the differential diagnosis of chest pain including pulmonary embolism, aortic dissection, pericardial effusion, or anterior pneumothorax. If the clinical scenario suggests one of these diagnoses but other, more fundamental testing is not definitive, contrast-enhanced spiral CT may be indicated. In addition, an echocardiogram may be useful for evaluating the patient for regional wall motion abnormalities, which may occur with coronary ischemia, left and right ventricular function, pulmonary hypertension, valvular disease, and pericardial effusion or tamponade.

Suggested Readings

Fink MP, Abraham E, Vincent JL, et al., eds. Textbook of Critical Care, 5th ed. Philadelphia: Elsevier Saunders, 2005:120–123.

Lee T. Chest discomfort and palpitations. In: Kasper D, ed. Harrison's Online, 16th edition. New York: McGraw-Hill, 2005.

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