SIADH: Nursing Diagnoses & Care Plans

Decreased Cardiac Output

Inadequate blood is pumped by the heart due to the massive fluid overload caused by excessive vasopressin secretion.

Nursing Diagnosis: Decreased Cardiac Output

Related to:

• Increased antidiuretic hormone release
• Aggravating fluid overload
• Impaired contractility
• Increased ventricular filling
• Decreased myocardial oxygenation
• Increased myocardial oxygenation demand

As evidenced by:

• Shortness of breath
• Chest pain
• Palpitations
• Anorexia
• Fatigue
• Orthopnea
• Alteration in mentation
• Crackles

Expected outcomes:

• Patient will manifest adequate cardiac output as evidenced by the following:
  • Blood pressure: Systolic BP >90 to <140; Diastolic BP >60 to <90
  • Heart rate: 60 to 100 beats/min with a regular rhythm
  • Respiratory rate: 12 to 20 breaths/min
  • Strong peripheral pulses
  • Absence of chest pain/discomfort
• Patient will not experience any changes in mentation.
• Patient will be normovolemic, as evidenced by the following:
  • Urine output 0.5 to 1.5 cc/kg/hour
  • Balanced intake and output
  • Stable weight
  • Maintained absence or reduction of edema

Assessment:

1. Assess and monitor the presence or degree of signs and symptoms such as:

• Exertional dyspnea
• Orthopnea
• Activity intolerance
• Paroxysmal nocturnal dyspnea
• Nocturnal cough
• Distended abdomen
• Fatigue
• Jugular vein distension
• Pulmonary rales
• S3 gallop
• Crackles
• Cool extremities
• Irregular heartbeat

These are signs and symptoms of heart failure and decreased cardiac output in which exertional dyspnea, activity intolerance, and orthopnea are the three most important symptoms.

2. Monitor for signs of hyponatremia, such as muscle twitches and cramps, confusion, nausea and vomiting, headache, etc.
In patients with congestive heart failure, there is an evident decrease in cardiac output and circulating volume, stimulating fluid and sodium retention. However, the uncontrolled release of AVP in SIADH promotes hyponatremia and aggravates the underlying cardiac dysfunction by causing systolic and diastolic myocardial wall stress and hypertrophy. Detection and early management of hyponatremia are crucial in managing concomitant heart disease.

3. Monitor daily weights.
Decreased cardiac output may lead to compromised regulatory mechanisms that result in fluid retention. A sudden weight gain of 2.2 lbs (1 kg) may indicate a liter of fluid retention. Patients with SIADH can retain 3 to 5 L. Monitoring body weight provides sensitive information on fluid balance.

Interventions:

1. Restrict free water.
Patients with heart failure and SIADH should restrict their water intake as first-line therapy. Guidelines recommend restricting water intake to 500-1500 mL/day.

2. Administer diuretics as prescribed.
Loop diuretics such as furosemide aid in eliminating excess water. Patients with heart failure and signs of fluid overload are treated with loop diuretics to reduce morbidity and mortality.

3. Consider vasopressin V2-receptor antagonists.
Tolvaptan is shown to be beneficial for patients with hyponatremia associated with CHF and SIADH. This medication is indicated for patients who are hypervolemic with less severe hyponatremia but who haven’t responded to fluid restriction.

4. Educate the patient about the therapeutic regimen and the association between SIADH and cardiac disease.
A thorough understanding of the therapeutic regimen and the nature of the disease aids in increasing adherence to the plan of care. Patients must understand the connection between fluid overload, sodium, symptoms, and cardiac workload.