Page 268 - ACCCN's Critical Care Nursing

Cardiovascular Alterations and Management 245

are the most common form of aortic aneurysms and are perfusion and maintain appropriate blood volume is also
located below the renal arteries. Bruits can also be heard essential. Finally, preparation for surgery is necessary, and
over the aneurysm. must include the patient and family.
Diagnosis VENTRICULAR ANEURYSM
A chest X-ray is usually the first investigation, and may Less than 5% of patients post-STEMI, particularly a
reveal a widened mediastinum or enlarged aortic knob. transmural anterior infarction, develop a left ventricular
Some aneurysms will be hidden, so normal chest X-ray aneurysm. Post-STEMI, dyskinetic or akinetic areas of
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does not exclude the diagnosis. If available, a CT scan, the left ventricle are common and known as regional
using contrast dye, provides accurate information on the wall motion abnormalities. It is in these areas that
location and size of the aneurysm. Transoesophageal there is a risk of an aneurysm developing. Ventricular
echocardiography (TOE) provides an accurate diagnosis aneurysms are more likely to develop post anterior
and is the preferred investigation in dissecting aneurysms. STEMI with a totally occluded LAD with poor collateral
TOE can clearly identify the tear/flap, to enable classifica- circulation.
tion of the aneurysm. There are some limitations in
viewing the ascending aorta, and patients with respiratory Aneurysms form when the intraventricular tension
dysfunction may have difficulty with lying flat for the stretches the dyskinetic area and a thin weak layer of
procedure and having a light anaesthetic. necrotic muscle and fibrous tissue develops and bulges
with each contraction of the ventricle resulting in a reduc-
Management tion in stroke volume. Aneurysms range from 1–8 cm in
Management of asymptomatic aneurysms is conservative, diameter and are four times more likely to occur at the
unless the size of the aneurysm is >1.5 times the normal apex and anterior wall rather than the inferoposterior
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size of the aortic segment or the situation is acute. The wall. Large ventricular aneurysms may result in a reduc-
primary aim is to lower hypertension and prevent increases tion in stroke volume causing an increase in myocardial
in thrombus size and emboli through the administration oxygen demand (MvO 2 ) resulting in angina and heart
of aspirin. Usually the patient has regular monitoring to failure. The mortality rate in people with ventricular aneu-
assess the aneurysm and to determine the timing and need rysms is four times higher than those with no aneurysm
for surgical repair. due to a higher risk of tachyarrhythmias and sudden
cardiac death. Unlike aortic aneurysms these aneurysms
Acute and dissecting aortic aneurysms are life-threatening rarely rupture so their management is usually conserva-
emergencies, and surgery is often the only option. The tive. Diagnosis of a ventricular aneurysm is by echocar-
development of new or worsening lower back pain may diography. Ventricular aneurysm should be considered
indicate impeding rupture and they may have a palpable when ST segment elevation persists beyond 1 week after
pulsatile abdominal mass. The faster treatment is initiated, myocardial infarction.
the higher the chances of survival with optimal recovery.
The primary goal is to control blood pressure. If hyperten- Management
sive, beta-adrenergic blockers or sodium nitroprusside are Management of a left ventricular aneurysm consists of
used to reduce further arterial wall stress. If the patient is aggressive management of STEMI and reperfusion therapy.
hypotensive, IV fluid and inotropes may be necessary. Long term anti-coagulation therapy with warfarin is
Nursing management of dissecting aortic aneurysm required. A complication of a ventricular aneurysm
involves the following: includes the development of an intraventricular thrombus
within the aneurysmal pocket which, if mobilised,
● support during the diagnostic phase; becomes arterial emboli. Also due to the high risk of
● assessment of pain and provision of analgesia; tachyarrhythmias, antiarrhythmic therapy is indicated. An
● stabilising and monitoring the clinical condition; ICD may also be necessary if antiarrhythmic therapy is
● providing psychological support to patient and family; unsuccessful in suppressing tachyarrhythmias. Surgical
and aneurysmectomy may also be required, if heart failure and
● preparation for surgery and long-term care. angina become severe, and is usually successful.
Assessment of the patient’s symptoms and effects of the SUMMARY
aneurysm is essential. This includes careful assessment and
recording of symptoms, including pain level and intensity, Compromise of the cardiovascular system, as either a
peripheral pulses, oxygen saturation levels, blood pressure primary or secondary condition, is a common problem
in both arms, and neurological symptoms to assist with that necessitates admission of patients to a critical care
diagnosis and detect progression. Intravenous analgesia is area. Prompt and appropriate assessment and treatment
essential to control the severe pain, and an antiemetic is is required to ensure adequate oxygen supply to the
useful to prevent opiate side effects. Opiates may also tissues throughout the body. The commonest cardiovas-
contribute to a sedative effect and slight vasodilation, cular problems experienced by patients include coronary
which are both beneficial. Oxygen therapy via mask should heart disease, arrhythmias and cardiogenic shock, however
be administered as indicated by oxygen saturation levels. heart failure, and selected conditions such as cardio-
Blood pressure control is vital, and usually IV medications myopathies, hypertensive emergencies, endocarditis and
are titrated to a narrow MAP range of 60–75 mmHg. Close aortic aneurysm also occur. Appropriate assessment
observation of fluid balance to detect changes in renal and management is essential to prevent secondary