Fluid management is a primary treatment option for managing patients with acute, chronic, or critical illnesses. Common conditions that require fluid replacement include:
* prolonged or severe vomiting
* prolonged or severe diarrhea
* infection
* gastrointestinal (GI) suctioning
* heart failure
* septic shock
* respiratory failure
* hemorrhage
* cardiovascular collapse
* surgical procedures
* trauma
* administration of nephrotoxic medications.
In this article, we'll review the basics of current fluid management practices.
Balancing act
The adult body comprises 60% water; infants, 80%. When the fine balance of water is either depleted or overloaded, the body can respond by causing cardiac symptoms, such as abnormal heart rhythms or an elevated or low heart rate or BP (see Understanding fluid balance).
Common signs of volume depletion are:
* lethargy
* decreased urine output (for example, infants who have no wet diapers for more than 3 hours or children, teens, and adults who have no urine output for more than 8 hours)
* dry oral mucous membranes
* dry skin with decreased elasticity
* sunken eyes or fontanels in infants
* thirst
* headache
* elevated or low heart rate
* elevated or low BP
* confusion or delirium
* absence of sweating or tears
* rapid breathing.
Common signs of volume overload include:
* increased weight
* ascites
* elevated or low BP
* elevated or low heart rate
* increased oral secretions
* tachypnea (increased respiratory rate of greater than 20/minute)
* increased pulmonary capillary wedge pressure (PCWP)
* increased central venous pressure
* jugular vein distention (JVD)
* increased intracranial pressure
* shortness of breath
* dyspnea
* initial increased urinary output
* decreased level of consciousness
* headache
* blurred vision
* irritability.
If you suspect volume depletion or volume overload, immediately consult with the medical team to ensure the patient is quickly evaluated and treatment initiated. Fluid can be replaced by encouraging patients to increase their oral fluid intake in nonemergent situations. In acute or emergent situations, such as when the patient's heart rate, BP, breathing, and mental status are altered, more aggressive treatment, such as administration of I.V. fluids, may be necessary.
Keep in mind that patients with certain acute or chronic diseases may have difficulty safely accommodating the addition of I.V. fluid to their circulating volume. When caring for a patient with a diagnosis of congestive heart failure (CHF), liver failure, pulmonary edema, kidney disease, low cardiac ejection fraction (EF), dilated cardiomyopathy, or severe cardiovascular disease, closely monitor for signs of fluid volume overload and cardiac distress (see Proceed with caution).
Age, sex, and volume
Recent research from the American Heart Association (AHA) evaluated whether age and sex affect how patients respond to rapid I.V. infusion of normal saline solution, how patients with heart failure with preserved ejection fraction (HFpEF) respond, and how rapid infusion of normal saline solution affects mean pulmonary artery pressure (MPAP) and PWCP.
The I.V. fluid utilized in the study was an isotonic solution of 0.9% normal saline solution. Isotonic solutions are often given to correct suspected volume depletion because they contain a salt concentration that's similar to the cells and blood flowing within the circulatory system. Rapid infusion was defined as an infusion of greater than 100 mL/minute of 0.9% normal saline solution. The research study evaluated 60 patients of various ages and both sexes from three major medical centers.
The research concluded that rapid administration of normal saline solution increased the filling pressure inside the heart in healthy patients. However, the rapid infusion of normal saline solution increased the MPAP and PCWP dramatically faster and higher in women over age 55. Women over age 55 required less I.V. fluid to attain a therapeutic PCWP. All women of various ages required only 1 L of rapidly infused normal saline solution to reach a PCWP of 16 mm Hg; men usually required 2 L to attain the same result.
Research showed that women, in general, responded well to infusions of 1 L of normal saline solution and that it improved their heart's cardiac output. Patients with a known diagnosis of HFpEF required less than 1 L of I.V. fluid to increase their PCWP to a crisis level of 25 mm Hg.
This study suggests that women over age 55 and those patients with a known diagnosis of CHF or HFpEF should receive an initial I.V. fluid loading trial because these patient populations require less I.V. fluid to obtain optimal outcomes. Fluid volume trials consist of administering small volumes of saline (less than 200 mL/30 minutes). After the initial loading trial, the patient should be reassessed to evaluate the need for additional I.V. fluids or treatment. Administering larger volumes may cause fluid volume overload, cardiac distress, pulmonary congestion, and cardiovascular collapse.
During the fluid loading trial, assess for signs of fluid volume intolerance, such as elevated heart rate, elevated respiratory rate, shortness of breath, hypertension, chest pain, and low urinary output. When administering I.V. fluid to any patient, consider administering a fluid volume trial because some patients may have undiagnosed CHF, renal disease, liver disease, or HFpEF.
Don't forget the lungs and the brain
Be aware that infusing I.V. fluid can also impact other organs, such as the lungs and brain. When performing an assessment, routinely auscultate the patient's lung sounds to identify signs of pulmonary congestion, such as crackles in the lower lobes of the lungs. When rapidly administering I.V. fluid, you should also monitor for new-onset changes in mentation, such as increased irritability, confusion, or lethargy, which can signal a neurologic emergency.
Administering large amounts of I.V. fluid can cause pulmonary congestion as fluid shifts into the lungs. In severe cases, it may cause pulmonary edema-the collection of fluid within the small alveoli of the lungs. As the lungs fill with fluid, oxygen and carbon dioxide are unable to transfer through the thin fragile walls of the alveoli.
A 2010 research study performed by the Mayo Clinic evaluated how rapid I.V. fluid infusions impacted the large and small airways of the lungs. The conclusion confirmed that rapid I.V. fluid infusions resulted in obstructive and restrictive changes in the smaller airways of the lungs and the alveolar pulmonary beds. As fluid accumulates in the small alveolar beds, normal air exchange is blocked, which may result in cerebral and tissue hypoxia.
You should suspect pulmonary congestion, pulmonary edema, or potential hypoxia if the patient exhibits the following symptoms:
* shortness of breath
* pink-tinged sputum
* dyspnea
* agitation
* lethargy
* low oxygen saturation levels
* crackles
* cough
* increased respiratory rate
* increased work of breathing
* JVD.
The brain is very sensitive to rapid changes in sodium and water balance. Severe hyponatremia (fluid overload) can cause neurologic changes because the brain cells become overly saturated with water. This oversaturation of water prevents the normal electrical impulses from efficiently transmitting signals, which may cause neurologic changes such as nausea, confusion, lethargy, seizures, coma, and even death.
Administering large amounts of I.V. fluid is often contraindicated in patients with traumatic brain injury (TBI). The immediate treatment plan for new-onset TBI patients is to reduce the circulating water volume within the brain to allow for additional room to swell (cerebral edema). The cranial vault (skull) is an unmovable object in adults. As the brain swells, it can compress and occlude the fragile blood vessels within the brain against the unmoving skull bone. This results in lack of oxygen to the lobes of the brain, and brain cell death (cerebral anoxia) quickly begins to occur.
Administration of large volumes of I.V. fluid can hydrate the brain, leaving little room for the brain to swell in TBI. Therefore, administration of large volumes of I.V. fluid in TBI patients can contribute to cerebral anoxia. Maintaining the fluid balance in neurologic patients ensures adequate circulating volume is maintained to perfuse the brain tissue and minimize complications from cerebral edema.
Monitoring maven
When administering I.V. fluid, closely monitor your patient's cardiac, respiratory, and neurologic status for changes. Research has shown that I.V. fluid should be tailored to each individual based on his or her known medical history, age, and sex for optimal patient outcomes.
Proceed with caution
CHF is a dysfunction that causes reduced cardiac output. It can range from the slight loss of normal heart function to the presence of signs and symptoms that no longer respond to medical treatment. In severe CHF, the heart can't pump enough blood to meet the body's metabolic needs. The addition of supplemental I.V. fluid can cause additional stress on the weakened heart. When receiving report on any CHF patient, ask if the patient has a daily fluid intake restriction ordered, what his or her EF is (if known), and whether the patient has any recent weight gain that could signal potential fluid retention.
When administering I.V. fluids to patients with CHF or HFpEF, closely monitor for signs of cardiac distress caused by fluid overload. A daily weight should be obtained at the same time each morning and recorded per your healthcare facility's policy. If any signs of cardiac distress arise, consider stopping the I.V. fluid and consult with the medical team immediately. Continuing the rapid infusion of I.V. fluid can lead to complete cardiovascular collapse. Rapidly infusing large volumes of I.V. fluid in a patient with CHF, HFpEF, or a reduced EF can cause the pressure within the heart and blood vessels to increase as fluid accumulates. This fluid may be forced to shift into other organs such as the lungs.
Common labs
Labs commonly ordered to evaluate for dehydration or fluid volume overload include:
* serum sodium
* urine sodium
* serum osmolarity
* urine osmolarity
* brain natriuretic peptide (BNP might increase with age, especially in women, making it less reliable as a diagnostic tool)
* creatinine.
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