Page 615 - ACCCN's Critical Care Nursing

592 S P E C I A LT Y P R A C T I C E I N C R I T I C A L C A R E

DESCRIPTION OF PRESENTING SYMPTOMS Acute Coronary Syndrome
AND INCIDENCE Chest pain of cardiac origin results from reduced or
The incidents of acute chest pain presentations appear to obstructed coronary blood flow, commonly by athero-
be increasing as patients are more aware of the impor- sclerosis, but also coronary artery spasm or an
tance of early treatment for myocardial infarction due to embolism. 73-75 Acute coronary syndrome (ACS) collec-
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public awareness campaigns. Up to 7% of all ED pre- tively describes unstable angina and acute myocardial
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sentations are for complaints of chest pain. The pain or infarction (AMI). Angina (stable or unstable) is pain but
discomfort is often described in variety of ways; as pres- no damage to myocardial cells. A time-critical obstruction
sure, a weight on the chest, tightness, constriction about results in death or necrosis of a segment of myocardial
the throat, or an aching feeling. The pain may also be cell resulting in an acute myocardial infarction (AMI).
described in less typical terms such as epigastric pain, Coronary heart disease is the largest single cause of death
indigestion, stabbing pain, pleuritic or sharp. 69,70 Onset is and the most common cause of sudden death in Australia
usually gradual, reaching a peak over 2–3 minutes and and New Zealand. It is the leading cause of premature
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last for several minutes or longer. 68,69 Pain may be mild death and disability in both countries, although death
to severe, and can be associated with physical exertion or rates have fallen since the 1960s. Over half of all coronary
emotional stress and may subside with rest, or be unpro- heart disease deaths were from AMI. ACS is the most
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voked and may wake the patient from sleeping. Pain may common life-threatening condition seen in the ED
also radiate to an arm, to both arms, to the neck, jaw or and therefore represents an important area of clinical
back. 67,69,70 A patient may have a number of associated practice. 58,73,77 Chapters 9 and 10 provide additional
symptoms including: shortness of breath, nausea, vomit- information about presentations of cardiac dysfunction,
ing, weakness, dizziness, anxiety, feeling of impending including the pathophysiology, clinical manifestations
doom, palpitations and diaphoresis. 69,71 Up to 9% of and treatment.
patients diagnosed with an acute coronary syndrome
(ACS) may present with a number of these associated Initial management focuses on rapid identification of
symptoms but without chest pain; these patients tend to patients with AMI and their suitability for reperfusion
be elderly, female or diabetic. 69,70,72 therapy. Reperfusion therapy involves either thrombolysis
or percutaneous coronary intervention (PCI) (angio-
plasty ± stent). PCI is usually only available to patients
ASSESSMENT, MONITORING in larger centres with cardiac catheter facilities. Manage-
AND DIAGNOSTICS ment in the ED includes oxygen therapy, administration
Any patient presenting with a complaint of chest pain of aspirin 300 mg (if not already administered by prehos-
requires urgent assessment (within 10 minutes of arrival pital personnel) and pain relief (commonly IV morphine
to the ED). A patient with evidence of a disturbance in small incremental doses, and nitrates initially sublin-
to airway, breathing or circulation requires close moni- gual route). If pain persists despite IV morphine, IV
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toring, immediate medical assessment and resuscitative nitrates may be indicated. Patient and family reassur-
interventions. Initial assessment includes a 12-lead ECG ance, information and emotional support is required to
and evaluation of the pain using the PQRST mnemonic allay anxiety and further stress.
shown in Table 22.3. The ECG should be rapidly evalu- Patients without initial evidence of AMI are stratified into
ated for presence of ST segment elevation or a new high-, intermediate- and low-risk groups based on the
left bundle branch block (LBBB) suggestive of an acute significance and duration of pain, ECG findings, past
myocardial infarction (AMI), as treatment for AMI is history, cardiovascular disease risk factors and cardiac
time critical. If the initial ECG is nondiagnostic and enzyme results. Specific treatment is guided by the associ-
symptoms persist, continue repeat ECGs at 15 minute ated risk pathway (see Chapter 10).
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intervals. 68
Thoracic Aortic Dissection
Continuous cardiac monitoring is commenced to iden-
tify any life-threatening arrhythmias, along with supple- A tear in the intimal layer of the aortic wall results in
mental oxygen to improve PaO 2 and increase oxygen a thoracic aortic dissection (TAD): blood passes through
availability especially in the presence of myocardial isch- the tear; separates the intima from the vessel media or
aemia. An IV cannula is inserted and routine venous adventitia resulting in a false channel; and shear forces
blood samples are collected for cardiac enzymes: tropo- lead to dissection as blood flows through the false
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nin T or troponin I. A physical examination may identify channel. Identification of this life threatening condi-
non-cardiac causes of the pain or complications associ- tion is important as patients often require immediate
ated with cardiac related conditions; 69,73 a number of sig- surgery; TAD is most common in men aged 50–70 years
nificant abdominal complaints may present with chest with a history of hypertension, while other risk factors
pain as a feature. 68,73 A CXR may also identify any poten- include Marfan’s disease, other connective tissue disor-
tial causes for the patient’s pain. ders, cocaine or ecstasy use, pregnancy and aortic valve
replacement. 69,72 TAD presents with acute and sudden
onset of severe pain (often described as sharp, tearing
CANDIDATE DIAGNOSES AND MANAGEMENT or ripping in nature) 69,72 which is maximal at symptom
Common cardiovascular diagnoses presenting to the ED onset. Pain is usually located in the midline, may be
include ACS and thoracic aneurysm. present in the back but rarely radiates. Pulse deficits or