28 Cardiovascular system
Key test results  • Blood tests show elevated potassium, serum lactate, and
BUN levels; increased urine specific gravity (greater than 1.020)
and urine osmolality; decreased blood pH; decreased partial
pressure of arterial oxygen; increased partial pressure of arterial
carbon dioxide; and possible decreased hemoglobin and hemat-
ocrit (if the client is bleeding).
• ABG analysis reveals metabolic acidosis.
Key treatments  • Blood and fluid replacement
• Control of bleeding
respiratory rate, and pulse oximetry every 15 minutes and monitor  
 the ECG continuously. A systolic blood pressure lower than
80 mm Hg usually results in inadequate coronary artery blood
flow, cardiac ischemia, arrhythmias, and further complications
of low cardiac output. When blood pressure drops below
80 mm Hg, increase the oxygen flow rate and notify the physician
immediately.
indicated.
• Insert an indwelling urinary catheter to measure hourly urine
output. If output is less than 30 ml/hour in adults, increase the
fluid infusion rate but watch for signs of fluid overload such as
an increase in pulmonary artery wedge pressure (PAWP). Notify
 the physician if urine output doesn’t improve. An osmotic diuretic
such as mannitol (Osmitrol) may be ordered.
• Monitor hemodynamic parameters (CVP, pulmonary artery
pressure [PAP], and PAWP).
• During therapy, assess skin color and temperature and
note any changes. Cold, clammy skin may be a sign of
continuing peripheral vascular constriction, indicating pro-
gressive shock.
MYOCARDIAL INFARCTION
Key signs and symptoms  • Crushing substernal chest pain that may radiate to the jaw,
back, and arms; lasts longer than anginal pain; is unrelieved 
by rest or nitroglycerin; may not be present (in asymptomatic
or silent MI); in women, possible atypical symptoms of pain or
fatigue
Key test results  • ECG shows an enlarged Q wave, an elevated or a depressed
ST segment, and T-wave inversion.
Key treatments  • Anticoagulants: aspirin, dalteparin (Fragmin), enoxaparin
(Lovenox), heparin I.V. after thrombolytic therapy
• Thrombolytic therapy: alteplase (Activase), streptokinase
(Streptase), reteplase (Retavase); should be given within 6 hours
of onset of symptoms but most effective when started within
3 hours
• Oxygen therapy
• Administer medications.
MYOCARDITIS
Key signs and symptoms  • Arrhythmias (S3 and S4 gallops, faint S1)
• Dyspnea
• Fatigue
• Fever
Key test results  • ECG typically shows diffuse ST-segment and T-wave abnor-
malities (as in pericarditis), conduction defects (prolonged PR
interval), and other supraventricular arrhythmias.
• Endomyocardial biopsy confirms the diagnosis, but a negative
biopsy doesn’t exclude the diagnosis. A repeat biopsy may be
needed.
contractility
Key interventions  • Assess cardiovascular status frequently to monitor for signs
of heart failure, such as dyspnea, hypotension, and tachycardia. 
Check for changes in cardiac rhythm or conduction.
• Stress the importance of bed rest. Assist with bathing as
necessary; provide a bedside commode. Reassure the client that
activity limitations are temporary.