Cardiac output is the amount of blood being pumped by the heart per minute and measured in liters/minute. It is calculated by multiplying the stroke volume, which is the amount of blood pumped out of the left ventricle during each systolic cardiac contraction, and the heart rate. Cardiac output is affected by three other factors as well including: preload, afterload, and contractility. Decreased cardiac output is a state in which an inadequate amount of blood is being pumped by the heart to meet the body’s metabolic demands.
In this article:
- Causes (Related to)
- Signs and Symptoms (As evidenced by)
- Expected Outcomes
- Nursing Assessment
- Nursing Interventions
- Nursing Care Plans
- References
Causes (Related to)
There are various reasons a person may experience a decreased cardiac output. Below is a brief list of potential causes:
- Hypertension
- Coronary artery disease
- Genetic cardiac disease
- Myocardial ischemia/infarction
- Congestive heart failure
- Shock
- Arrhythmias
- Cardiac structural abnormalities
- Pericardial effusions
- Cardiac tamponade
This is not a comprehensive list as many different causes for decreased cardiac output exist. It is important to keep in mind that sometimes it may take a while for a patient to experience clinical signs and symptoms of decreased cardiac output due to these potential causes. Regardless though, it is important as the nurse to understand how other cardiac conditions can ultimately affect the patient’s cardiac output.
Signs and Symptoms (As evidenced by)
Signs and symptoms of decreased cardiac output can manifest in different ways. First, listed below are physiologic signs and symptoms a nurse may begin to notice.
- Hypotension
- Hypercapnia
- Cardiac arrhythmias
- Chest pain
- Poor tissue perfusion (diminished pulses)
- Clammy, cool skin
- Dizzy/lightheaded/syncope
- Fatigue
- Weakness
- Edema
- Decreased urine output
- Altered mental status
In addition to these signs and symptoms, patients may also display psychological signs and symptoms such as:
- Restlessness
- Anxiety
- Altered mental status/confusion
Expected Outcomes
The following are the common nursing care planning goals and expected outcomes for decreased cardiac output:
- Patient will show adequate cardiac output as evidenced by blood pressure, heart rate, and rhythm within normal limits.
- Patient will be able to return to baseline activity level.
- Patient will display adequate breathing as evidenced by appropriate oxygen saturation level and absence of adventitious breath sounds.
- Patient will be able to verbalize future self-care activities to improve cardiac health.
Nursing Assessment
The first step of nursing care is the nursing assessment, during which the nurse will gather physical, psychosocial, emotional, and diagnostic data. In the following section, we will cover subjective and objective data related to decreased cardiac output.
1. Monitor heart rate and blood pressure.
Low cardiac output can stimulate the sympathetic nervous system. This is done to compensate for the low cardiac output and can result in increased heart rates and initially an increased blood pressure. Later on, blood pressures may drop and patient can become hypotensive.
2. Monitor breath sounds, respiratory rate and pattern, and oxygen saturation.
Patient may experience an increase in shortness of breath as cardiac output decreases. Assessing oxygen saturation will allow for objective data regarding the patient’s breathing status. Adventitious breath sounds are also common such as crackles.
3. Monitor heart rhythm.
Decreased cardiac output can result in cardiac arrhythmias. A common cardiac arrhythmia seen in these patients is atrial fibrillation. Alternatively, arrhythmias can be the cause of decreased cardiac output. Arrhythmias such as ventricular tachycardia are a medical emergency and require immediate intervention.
4. Monitor heart sounds.
Normal heart sounds include S1 and S2. These may be diminished with poor heart function. In addition, heart sounds S3 and/or S4 may become audible which are signs of heart failure.
5. Assess peripheral pulses.
Decreased cardiac output can result in poor tissue perfusion and decreased or diminished pulses peripherally.
6. Assess skin color and temperature.
As the patient’s cardiac output decreases, tissue perfusion can worsen and the patient’s skin may become cool, clammy, and pale due to decreased oxygen saturation in the body.
7. Assess the patient’s mental status.
Due to decreased oxygen saturation, patients may have altered mental status and become confused.
8. Assess lab values and results of any imaging studies.
These can help to indicate potential causes or underlying conditions that may be contributing to the low cardiac output.
9. Monitor weight closely.
Decreased cardiac output could result in retention of fluid which can worsen the symptoms the patient is experiencing.
10. Monitor intake and output closely.
This will allow the nurse to maintain appropriate fluid balance.
11. Monitor patient’s activity level.
Patients may become fatigued more quickly when cardiac output is low.
Nursing Interventions
Nursing interventions and care are essential for the patients recovery. In the following section, you’ll learn more about possible nursing interventions for a patient with decreased cardiac output.
1. Administer supplemental oxygen as needed.
Patient’s oxygen saturation may be low and may require supplemental oxygen in order to maintain appropriate levels. Appropriate oxygenation is necessary to improve overall condition and bodily functions.
2. Administer prescribed medications as ordered.
Various medications may be ordered for patients with decreased cardiac output (i.e. ACE, ARBs, etc.). These will help to improve heart function and decrease patient’s symptoms and cardiac workload.
3. Elevate the head of the bed.
Elevating the head of the bed will allow the patient better positioning for breathing and be able to maintain an appropriate oxygenation level.
4. Maintain fluid restriction and/or sodium restriction.
Patients with low cardiac output are more prone to retaining additional fluids and can be very sensitive to sodium. A fluid and/or sodium restriction may be necessary to minimize fluid retention.
5. Initially allow for bedrest during acute phase. As the patient’s status improves, slowly begin activity to increase tolerance and stamina.
Patients with decreased cardiac output can become deconditioned quickly. Initially, bedrest is warranted until the patient is able to reach a stable cardiac and respiratory state. Once stable, slowly increasing activity level will help to strengthen muscles including cardiac muscles.
6. Educate the patient on home self-care.
Providing education for patients will allow them to understand the pathophysiology of what is occurring in regards to their health. Education will also assist patients in understanding measures they can take at home to improve their cardiac health and prevent further deterioration.
7. Place the patient on a cardiac monitor.
Cardiac arrhythmias are common with decreased cardiac output. It is important to be able to monitor for these and then treat as appropriate should an arrhythmia develop.
8. Educate patient to avoid Valsalva maneuvers.
These maneuvers can put extra strain on the cardiac muscle.
9. Implement a rehabilitation plan for activity (PT and/or cardiac rehab).
These types of programs can improve the patient’s quality of life and decrease mortality.
10. Anticipate potential for deterioration.
Patients who have decreased cardiac output may be at risk of cardiac arrest. Watch for deteriorating vital signs, changes in level of consciousness or increases to patient anxiety. It may be necessary to alert the medical team and anticipate the need for resuscitation if the patient continues to deteriorate.
Nursing Care Plans
Nursing care plans help prioritize assessments and interventions for both short and long-term goals of care. In the following section, you will find nursing care plan examples for decreased cardiac output.
Care Plan #1
Diagnostic statement:
Decreased cardiac output related to altered heart rate secondary to bundle branch block as evidenced by ECG changes and chest pain.
Expected outcomes:
The patient will demonstrate adequate cardiac output as evidenced by:
- Heart rate 60-100 beats per minute
- Blood pressure 90-130/60-90 mmHg
- Regular sinus rhythm
- Absence of chest pain
- Absence of dyspnea
The patient will not manifest a decrease in the level of consciousness.
Assessment:
1. Monitor chest pain.
Note precipitating and relieving factors, quality, radiation, severity, time (onset and duration), location, and associated symptoms such as excessive sweating, nausea, and indigestion. Chest pain may indicate myocardial ischemia leading to decreased cardiac output. If decreased cardiac output is not adequately addressed, it will lead to end organ damage.
2. Monitor ECG findings.
Bundle Branch Block is an incidental ECG finding and may be asymptomatic. However, the lack of signs and symptoms does not exclude diagnosing a heart condition. A bundle branch block indicates progressive myocardial degeneration. Hence, BBB associated with cardiac symptoms may already imply a worsening underlying myocardial dysfunction.
Interventions:
1. Instruct the patient to relax during the chest pain episodes.
Relaxing helps decrease myocardial oxygen demand and restore supply and demand balance.
2. Administer sublingual nitroglycerin every 5 minutes for a maximum of three doses until chest pain is relieved.
Chest pain is indicative of myocardial ischemia requiring urgent therapy. Nitroglycerin, taken sublingually, relieves acute chest pain by dilating cardiac arteries and veins, thereby improving cardiac tissue perfusion.
3. Administer oxygen as indicated.
Increasing arterial oxygen saturation increases oxygen delivered to the heart.
4. Educate the patient on avoiding angina-provoking factors such as heavy meals, excessive physical exertion, extreme temperatures, emotional stress, and stimulants.
It is in the patient’s control not to engage in these circumstances. Knowing these factors will help in increasing compliance.
5. Refer to a cardiac rehabilitation program for education and monitored exercise.
Exercise training is recommended for patients experiencing decreased cardiac output. Cardiac rehabilitation can improve quality of life and functional capacity and reduce mortality.
Care Plan #2
Diagnostic statement:
Decreased cardiac output related to altered rhythm secondary to atrial fibrillation as evidenced by irregular pulse and dizziness.
Desired outcomes:
The patient will demonstrate adequate cardiac output as evidenced by:
- Regular sinus rhythm
- Strong regular peripheral pulses
- Heart rate 60-100 beats per minute
- Blood pressure 90-130/60-90 mmHg
The patient will not experience falls or injuries from dizziness.
Assessment:
1. Hook to ECG monitor.
Patients experiencing atrial fibrillation are at increased risk for thromboembolism, stroke, and premature death. Prompt management is necessary. Use continuous cardiac monitoring to assess rate and rhythm of the heart.
2. Monitor hemodynamic parameters (i.e., pulmonary wedge pressure, systemic vascular resistance, stroke volume, and cardiac output).
If the patient is hemodynamically unstable, central monitoring may be necessary. Cardiogenic shock may occur as a devastating complication of atrial fibrillation. Increased pulmonary wedge pressure, elevated systemic vascular resistance, or decreased stroke volume, cardiac output, and cardiac index may be present in patients with shock.
3. Identify the underlying cause of atrial fibrillation.
If the patient is not currently hemodynamically unstable, the nurse should focus their assessment on identifying the underlying cause of the atrial fibrillation. The nurse should ask about the timing and frequency of the episodes, previous episodes, history of cardiovascular disease and current medication usage.
Interventions:
1. Place the patient in a semi-Fowler’s to high-Fowler’s position and administer oxygen therapy as prescribed.
These measures help to maintain adequate ventilation and perfusion.
2. If the patient is hemodynamically unstable, anticipate immediate cardioversion.
Cardioversion can be completed either using a bolus of IV medication or by using electricity. In either case, the goal is to “reset” the sinoatrial node with the goal that the heart starts beating in a normal sinus pattern.
3. Administer medications as ordered.
Calcium channel blockers or beta blockers are usually given to reduce or prevent rapid ventricular response by controlling cardiac rate and rhythm. Depending on the patient’s risk level, they may also be prescribed a long term anticoagulant.
4. Educate the patient about lifestyle modification activities.
- Medications: Patients should be educated on the importance of medication adherence including risks of bleeding related to anticoagulation if prescribed.
- Diet: If the patient is on warfarin, note that foods high in Vitamin K such as kale, spinach, broccoli, animal liver products, and lettuce can affect clotting factors and make warfarin less effective.
- Avoid alcohol and caffeine as these substances can trigger atrial fibrillation.
- Smoking cessation: Nicotine is a cardiac stimulant that can aggravate the dysrhythmia
- Be wary of OTC medications (e.g. cold remedies and nasal spray) that contain cardiac stimulants and worsen atrial fibrillation
- Stress triggers atrial fibrillation. Doing relaxing techniques may help to prevent dysrhythmia.
5. Refer the patient to a community resources program for education, evaluation, and guided support to increase activity and rebuild the quality of life.
Depending on the aetiology and severity of the atrial fibrillation, it can be a complex disease to manage. Patients should be referred to outpatient clinics for follow up and education about disease management and lifestyle modifications. Multidisciplinary care systems designed to support clients with atrial fibrillation can improve outcomes.
References
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