Stabilization of Chest Pain
The Approach to Chest Pain

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Introduction


      Patients with chest pain are the leading cause of malpractice losses to emergency physicians and internists. Failure to diagnose myocardial infarction (MI) accounts for 10 percent of the cases filed against emergency physicians. Judgments and settlements in these cases total 25 percent of the dollars paid out to claimants.
      In a recent study, all discharged chest pain patients came back for further testing the next day. Five percent of MI patients had been sent home. What factors lead to inappropriate discharge? Physician inexperience (less than 3 years practice) and atypical presentation.
      Myocardial infarction may become an even bigger cause of litigation in the future. Because thrombolytics can lower mortality and improve cardiac function, suits will be filed by patients who have lost the opportunity to receive this therapy. Back to Index.


Initial Stabilization

      Patients presenting to the emergency department with chest pain should be triaged immediately to the treatment area. Evaluation and stabilization should begin at once.
      The patient with acute chest pain should be approached in much the same manner as the multiple-trauma patient: Stabilize the patient and treat life-threatening conditions while obtaining the historical and physical exam information.
      Any patient who presents in obvious distress, has abnormal vital signs, or who volunteers a history of cardiac-compatible chest pain, should be immediately stabilized with oxygen, cardiac monitor, and IV. In most emergency departments, several care-givers will stabilize the patient, simultaneously placing nasal oxygen, cardiac monitor, and IV, and obtaining vital signs.
      If only one person is available to care for the patient, place oxygen first, to obtain its rapid therapeutic benefits. Most protocols use 4 liters by nasal cannula. Next attach the cardiac monitor (at this point, the most likely urgent need is cardioversion of an evolving arrhythmia such as V-tach). Now start the IV at a keep-open rate. The choice of D5W or normal saline is hotly debated, and probably makes no practical difference. Once the IV is running, take vital signs.
      Just as with trauma care, act to correct a life-threatening abnormality found during initial stabilization before progressing on with the work-up. For example, if V-tach is seen when placing the cardiac monitor, the physician takes action: he checks skin color, skin temperature, and radial pulse; he decides the patient is unstable, and orders an unsynchronized counter-shock. No vital signs; no 12-lead ECG — when the clinical threshold for action is reached, the physician should act.
      As a second example, suppose initial vital signs show significant hypotension. The physician immediately obtains the specific information he needs to act: he quickly looks at the neck veins, listens for rales, and checks the heart tones. Then he intervenes. For example, he might order a saline fluid challenge.
      Acting on information as it is received continues during the “history and physical” portion of the evaluation. Once the physician knows the pain is cardiac-compatible, he should not wait until after the Babinski reflexes are tested to give nitroglycerin. Nitroglycerin should be ordered as soon as the indications for (and lack of contraindications to) its use are established. Similarly, morphine is given when it’s determined that the nitroglycerin has been ineffective. These interventions should be considered part of the stabilization process. Back to Index.


Obtaining the Chest Pain History

      Most of the important decisions the physician must make will be based on the history of the chest pain. When physical findings and lab tests are non-specific, as they often are in chest pain patients, the history alone will decide whether the patient is admitted to the hospital.
      The history looks for clues to life-threatening causes of chest pain: myocardial infarction, unstable angina, pulmonary embolism, pneumothorax, mediastinitis (esophageal rupture), and aortic dissection. “Pertinent negatives” (absence of symptoms that would make any of these diagnoses more likely) are an important part of the historical documentation.
      Obtain an accurate description of the pain’s onset, duration, severity, nature, location, aggravating or alleviating factors, and prior episodes. Specifically note the presence or absence of radiation of pain and any associated symptoms (nausea, shortness of breath, sweats) and their severity.
      Have the patient describe how the pain started. The pain of angina or myocardial infarction builds up, while aortic dissection and pulmonary embolism tend to cause “instant severe pain.” What was the patient doing? Angina at rest has a very different prognosis from angina while running up the stairs. Pain starting as the patient swallows a bolus of food suggests esophageal pain.
      The duration of the pain also helps establish the cause. Pain that lasts only a second or two, or pain that is constant for many days, is almost never cardiac pain. Angina typically lasts five to 15 minutes — pain for less than a minute is unlikely to be angina.
      The nature of the pain can suggest the diagnosis. If the patient doesn’t volunteer a description, ask him what the pain reminds him of: burning, squeezing, pressure, tearing, stabbing. A description as poking, pinching, or stabbing usually means chest wall pain. Hyperventilation often causes poking pains that are migratory and unrelated to motion. Victims of aortic dissection will often describe a well-localized “tearing” type pain. However, when the patient has pain from the internal organs (heart, esophagus, gallbladder), the nature of the pain is unhelpful at best, and is often misleading: a victim of myocardial infarction may complain of “heartburn,” while the patient with esophagitis may complain of a squeezing sensation.
      Ask about the location of the pain. Pain from the internal organs of the chest tends to be felt over a wide area. But try to make the patient commit to a location and size of the area of pain. If the pain is small in area, located over the chest wall, and corresponds to an area of tenderness, it’s probably chest wall pain. Work-up of the patient who has several small and migratory locations of pain “like tiny pins” usually will reveal no organic disease.
      Question the patient about radiation of the pain. Chest pain from reflux esophagitis, ulcer, or gallbladder will usually have an epigastric component, but rarely radiates to the arms. Aortic dissection usually hurts in the back. And of course, pain radiating to the jaw, shoulders, or arms suggests (but is not diagnostic of) cardiac pain.
      Ask what things affect the pain. Ask specifically whether breathing makes it worse. Three-fourths of pulmonary embolism victims will have pleuritic pain. Worsening with position or with motion of the arms is expected with chest wall pain, but can occur with any cause of pleuritic pain, such as pericarditis or pleurisy. If resting stops the pain, ask how long it takes to go away. Angina will usually take a minute to ease, while other activity-related pains often stop instantly with rest.
      Prior episodes of identical pain are helpful. A history of multiple episodes of the same pain, lasting hours each time, virtually excludes myocardial infarction. Ask about any constant factors for these past episodes, such as: relation to meals or time of day, duration of pain, and factors affecting the pain. Be sure to ask if there has been any previous work-up.
      When the history seems confusing, you may be dealing with more than one cause of chest pain. A patient with angina on exertion also may have musculoskeletal chest pain with activity, and may have “lumped” these pains into one. A patient with an MI after a meal may have had past episodes of heartburn or gallbladder pain after meals. Careful questioning about the exact sensations of specific episodes can help you avoid a mistaken diagnosis.
      Ask for risk factors of cardiovascular disease or pulmonary embolism. Your chart should list them as “pertinent negatives.”
      Your decisions won’t be based on any single factor in the history. The entire history “snapshot” is required. For example, “hurts on my ribs when I move my arm” doesn’t automatically mean musculoskeletal chest pain. It must be considered as part of the “42 y.o. female smoker on BCP with fractured leg in cast who’s short of breath, hurts to breathe and hurts in ribs when she moves her arm” picture.
      Both absolute and relative contraindications to thrombolytic therapy should be sought. Ask specifically about recent melena, active ulcer disease, recent major surgery, stroke, or brain tumors or vascular malformations. If the patient is diabetic, ask about retinal vascular disease. As you conclude the history, you may already have decided that the patient will be admitted. Back to Index.


The Physical Exam in Chest Pain

      As experienced physicians know, the most important part of the physical exam of the chest pain patient is the first “lookover.” Poor skin color, diaphoresis, tachypnea, and anxious expression alert the physician to a potentially lethal process. The Gestault of the patient serves as a highly accurate “severity-O-meter.”
      Evaluate the meaning of the vital signs. Tachycardia is non-specific — it can suggest shock, severe pain, or physical stress — but it serves to alert the physician. Tachycardia is particularly likely with pulmonary embolism. Blood pressure should be checked in both arms. A difference of over 20 mm Hg systolic suggests aortic dissection — and will be present in about two thirds of cases. Hypotension may suggest massive PE or cardiac shock. Fever may suggest pneumonia or mediastinitis as the cause of chest pain. Tachypnea may simply reflect severity, or can suggest pulmonary embolism or hyperventilation.
      Your exam should seek general evidence of atherosclerosis (or risk factors for ASVD). Note corneal lipid rings, narrowed retinal arteries, and pigment and hair changes in the legs.
      Evaluate the neck veins for distension. Check the carotids for quality of pulse, and for bruits. The chest wall should be inspected for respiratory motion, respiratory retractions or accessory muscle use, and precordial motion. Identify the apical impulse (PMI). Feel for tender areas. Many older patients will have tenderness. Only if the tender area corresponds to the location of the patient’s pain, palpation exactly reproduces the pain, and the history suggests chest wall pain, should the physician diagnose musculoskeletal chest pain.
      Check the lungs for rales, wheezes, and asymmetrical breath sounds. Asymmetry of breath sounds may be found in about half of patients with spontaneous pneumothorax. However, asymmetry also can be due to splinting of the painful side of the chest in other conditions that cause pleuritic pain. Wheezing will most likely be due to underlying COPD, but can occur due to heart failure (cardiac asthma) or pulmonary embolism.
      Listen to the heart tones. Wide physiologic splitting of the second heart sound (splitting wider with inspiration) can be found in right bundle branch block or in right ventricular infarction. New paradoxical splitting is most often due to left bundle branch block, or anterior or lateral infarction. A new fourth heart sound (preceding the first heart tone) can occur with angina or infarction. An S3 (third heart tone) is more likely due to underlying heart failure.
      A new murmur may be significant. Aortic regurgitation occurs in over half of patients with aortic dissection. New mitral regurgitation can occur in patients with angina or infarction, and is due to papillary muscle dysfunction.
      The extremities should be examined for pulses, edema, calf tenderness, and signs of atherosclerotic vessel disease. Absence of pedal pulses may occur in aortic dissection. Any swelling of the legs, especially if unilateral, raises the odds of pulmonary embolism as the cause of chest pain. Pulmonary embolism often occurs in patients with CHF. Back to Index.


Diagnostic Maneuvers

      Trial therapy of chest pain in the emergency department can be misleading. The placebo response may result in improvement of chest pain in about one fourth of chest pain patients, no matter what the intervention. The spontaneous improvement of pain may be attributed to a specific therapeutic trial, resulting in false diagnosis.
      Patients with cardiac-compatible pain should be given sublingual nitroglycerin. About three fourths of patients with angina will have complete pain relief within two minutes. However, most patients with esophageal spasm also will have pain relief with nitroglycerin. Relief with nitroglycerin is not diagnostic of cardiac pain.
      A “GI Cocktail” of antacid and lidocaine can be given for potential pain relief, but should not be relied on for diagnostic purposes. Only 25 percent of emergency patients with reflux esophagitis will have relief of pain with the GI cocktail. More ominously, about 20 percent of MI patients will report some relief of pain with the GI cocktail. The spontaneous resolution of an episode of unstable angina after administering a cocktail may lull the physician into making a mistaken diagnosis — one with potentially fatal consequences for the patient. Back to Index.


Monitoring the Patient During Work-up

      The chest pain patient should be kept on continuous cardiac monitor. At first, a nurse should be present at the bedside. If the patient remains stable (no change in pain pattern, no change in vital signs), the patient can later be monitored by telemetry.
      Blood pressure should be frequently monitored, preferably by automatic bedside equipment that provides a written printout.
      Pulse oximeters are often misleading (the usual problem is false reassurance — a good oxygen saturation is reported in a patient who later turns out to have horrible blood gases). However, they are useful because they are fast and simple, and can monitor for a change in saturation.
      The attending nurse should watch for changes in skin color, respiratory rate or effort, sweating, or patient expression. The nurse also should report any change in the patient’s symptoms. The physician should reevaluate the patient immediately if any significant change occurs. Back to Index.


Laboratory Evaluation of Chest Pain

      Unless the pain is obviously musculoskeletal, all patients with chest pain should have a 12-lead ECG. To speed possible thrombolytic therapy, do the ECG as soon as safe and practical — immediately after initial stabilization and taking of vital signs. If the ECG machine is “busy” elsewhere, give treatment (if needed) such as nitroglycerin, morphine, or lidocaine while awaiting the ECG.
      Most patients with myocardial infarction will have an abnormal initial ECG, although the ECG will not necessarily be diagnostic of an MI. About one-fourth of acute MI patients will present with a completely normal ECG.
      An abnormal ECG can be seen in many non-cardiac conditions. If so, the physician has the duty to demonstrate that the ECG abnormality is either old, unrelated to the chest pain, or caused by a non-cardiac condition. Examples of acute conditions affecting the ECG include pulmonary embolism, electrolyte abnormalities, or CVA. Almost 90 percent of patients with dissection will have an abnormal ECG, often suffering acute MI due to involvement of the roots of the coronary arteries.
      Obtain a chest x-ray on all patients with chest pain, unless the pain is obviously musculoskeletal. The x-ray may show pneumothorax, pneumomediastinum (such as from esophageal rupture), pleural effusion, or infiltrates. Subtle findings such as loss of lung volume or unilateral decrease in vascular markings may suggest pulmonary embolism. Dissection of the aorta can cause a wide mediastinum or aortic knob contour changes.
      If the pain is cardiac-compatible, blood tests should include a multichannel survey with electrolytes, complete blood count, clotting studies (PT & PTT), and baseline CPK. If the physician suspects a non-cardiac diagnosis, such as pneumonia or pancreatitis, other tests may be helpful.
      The CPK should not be used as a basis for admitting the acute chest pain patient to the hospital. The initial CPK is often normal in acute myocardial infarction. However, if the pain has been present for eight to 12 hours, it’s reasonable to exclude myocardial infarction in the patient with normal CPK-MB and normal ECG.
      Draw blood gases for patients in obvious respiratory distress, patients who may have shock or sepsis, patients in whom the diagnosis of PE can be ruled out by normal room air blood gases, and patients with underlying lung disease who must have monitoring of oxygen therapy. A normal arterial-alveolar diffusion gradient on room air gases essentially excludes significant PE.
      If the pain is cardiac-compatible, it’s best to await the ECG before ordering blood gases, if the gas analysis is not critical for early management of the patient. If the ECG shows infarction and thrombolytics are given, bleeding may prove problematic at the arterial puncture site.
      Other studies, such as perfusion scan, arteriogram, and gallbladder ultrasound, are ordered based on clinical suspicion concerning the cause of the chest pain. These studies should NOT be ordered routinely on a “Rule-out MI” patient to “fish” for another diagnosis. Back to Index.


Disposition of the Chest Pain Patient

      The physician must make a decision on admission or outpatient work-up and therapy. Life-threatening causes of chest pain must be eliminated through historical, physical, and laboratory data before the patient can be discharged to out-patient follow-up. These critical diagnoses are unstable angina, myocardial infarction, pulmonary embolism, pneumothorax, mediastinitis, and aortic dissection.
      Of the above diagnoses, all except pneumothorax require automatic admission. A small pneumothorax can be tapped in the emergency department, or simply observed, with careful outpatient follow-up.
      Patients with less-lethal causes of chest pain may still require admission if the severity of the disease, underlying poor health, or patient distress warrants it. An unfortunate side effect of recent Medicare regulations is that the physician may have to summon greater investigative skills to find the “criteria” for admission than was necessary to diagnose the problem.
      Any patient with cardiac-compatible chest pain should be admitted to the hospital as a “Rule-out MI,” unless the pain has been proven to have another etiology. Although undiagnosed chest pain patients with normal initial ECG and CPK have only a .01 percent (one-hundredth of a percent) risk of life-threatening complications, today’s legal climate does not allow the more cost-effective treatment protocols used in other countries. Back to Index.


Thrombolytics

      WHICH thrombolytic is used is infinitely less important than that a thrombolytic IS given, and as early as possible. The physician should usually make the decision to use thrombolytics within 20 minutes of the patient’s arrival.
      The physician can obtain the chest pain history while the treatment team places the patient on oxygen, cardiac monitor, and IV. This initial history includes specific questions about contraindications to thrombolytics.
      Obtain the ECG when it can be done without getting in the way of basic stabilization, usually within three minutes of arrival. Meantime, the physician is examining the patient.
      Give nitroglycerin when vital signs have been obtained. By the third nitroglycerin dose, the physician is ready to order the thrombolytic.

Back to Chest Pain Manual Index



Copyright 1996 Mad Scientist Software
Citation:
Argyle, B., Blood Gases Computer Program Manual.
Mad Scientist Software, Alpine UT, 1996.
 

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