Learning Objectives
By the end of this section, you will be able to:
- Recognize cues for fluid, electrolyte, and acid-base balance when providing patient care
- Identify nursing tasks to prevent fluid, electrolyte, and acid-base imbalances
The human body has multiple mechanisms in place to maintain a narrow range of fluid balance, electrolytes, and acid-base levels. If any of these components of homeostasis is out of the normal range, the patient is at risk for organ dysfunction, and if left untreated, even death. It is imperative that nurses recognize subtle changes in fluid imbalance, electrolyte levels , and acid-base homeostasis so they can intervene early and prevent patient complications. To accomplish these goals, nurses are constantly evaluating their patients and updating their plan of care as their clinical condition changes. In contrast to other healthcare disciplines, bedside nurses are in a unique position to pick up on trends early in the patient’s clinical course and adjust the plan of care as needed.
Recognizing Cues of Fluid, Electrolyte, and Acid-Base Balances
Nurses use cues to recognize change in clinical status. Subjective or objective data points that are observed by the nurse are known as cues. Patient cues can be an indicator of a clinical improvement or a deterioration. Common cues that nurses integrate in their clinical judgement are changes in vital signs, changes in mental status, and the presence or absence of pain (Burdeu et al., 2020). Cues for fluid, electrolyte, and acid-base balance are specific to the type of imbalance that is occurring. For example, cues for a fluid imbalance include a change in the patients’ weight, urine output, and skin turgor, whereas cues for an electrolyte imbalance include mental status changes, changes in muscle tone, and cardiac arrhythmias. Cues for acid-base imbalances can be seen in the two body systems that regulate acid-base levels: the respiratory system and the renal system. Nurses should also consider the possibility of gastrointestinal loss of acid (through vomiting) and base (due to diarrhea) when considering cues of acid-base imbalances.
Nurses complete a focused assessment, or the collection of relevant information pertaining to a change in the patient’s clinical status, to monitor a condition that could potentially lead to a complication. For example, if a patient has new onset abdominal pain, the nurse completes a focused assessment of the abdomen. This exam includes a description of the pain, where the pain is located, if the pain radiates, if there are unusual abdominal exam findings, and if there are factors that either alleviate or exacerbate the pain. This same model of thinking about a focused assessment can be applied to patients experiencing fluid, electrolyte, or acid-base imbalances (Toney-Butler & Unison-Pace, 2022).
Clinical Safety and Procedures (QSEN)
QSEN Competency: What To Do If Your Patient Has Dilutional Hyponatremia
| Steps | Description/Rationale |
|---|---|
| Confirm the diagnosis. | Hyponatremia can be caused by excess free water, which causes dilutional hyponatremia, or sodium loss. The treatment is different depending on the cause. Understanding the patient’s physiology is necessary to provide safe nursing care. |
| Perform an hourly neurological exam. | Hyponatremia can cause mental confusion. Closely monitoring for subtle neurological changes can provide cues to if the patient’s clinical status is changing. |
| Monitor input and output closely. | The kidneys, in conjunction with aldosterone, regulate serum sodium levels. Changes in urine output and total fluid balance can have a significant impact on serum sodium levels. |
| Anticipate an order to restrict fluids. | Patients with dilutional hyponatremia have excess free water in their serum. The first line of treatment is to limit fluid intake. If fluid restriction does not fix the hyponatremia, diuretics to help remove excess water may be prescribed. |
| Anticipate sending frequent serum sodium levels. | Patients with dilutional hyponatremia can become severely ill if their hyponatremia does not resolve. To monitor the patient’s response to treatment, it is normal to check the serum sodium level frequently until the hyponatremia resolves (Workeneh et al., 2023). |
The metrics that nurses monitor in response to a change in clinical status depends on the type of imbalance noted. For example, with both a fluid volume deficit and a fluid volume excess, nurses need to pay close attention to intake, output, and daily weights. On the other hand, with an acid-base imbalance, the key assessment to monitor is the patient’s blood gas. Table 20.3 summarizes key assessment criteria to consider for different fluid, electrolyte, and acid-base imbalances.
| Imbalance | Key Assessment Criteria |
|---|---|
| Fluid volume imbalances |
|
| Sodium |
|
| Potassium |
|
| Calcium |
|
| Magnesium |
|
| Respiratory acidosis or alkalosis |
|
| Metabolic acidosis or alkalosis |
|
An arterial blood gas is a blood test that measures the levels of oxygen (measured partial pressure [PaO2] and calculated saturation [SaO2]) and carbon dioxide (PaCO2) in the arterial blood, as well as the pH and levels of bicarbonate ions (HCO3–) (Table 20.4). It is a crucial diagnostic tool used to assess a patient’s acid-base balance and oxygenation status. Nurses play a vital role in obtaining ABG samples, ensuring accurate collection and handling, and interpreting the results in collaboration with healthcare providers.
| Parameter | Normal Range |
|---|---|
| pH | 7.35 – 7.45 |
| PaO2 | 75 – 100 mm Hg |
| PaCO2 | 35 – 45 mm Hg |
| HCO3– | 22 – 29 mEq/L |
| SaO2 | 95 – 100% |
Nurses monitor these parameters closely, recognizing deviations from normal ranges that may indicate respiratory acidosis or alkalosis, metabolic acidosis or alkalosis, or hypoxemia, which is defined as low oxygen levels in the blood. Hypoxemia can lead to compensatory mechanisms such as increased respiratory rate or cardiac output, which may affect acid-base balance. ABG results provide important cues to guide nursing interventions, such as adjusting oxygen therapy, ventilatory support, or administering medications to correct acid-base imbalances. See (Table 20.5) for a quick reference for interpreting ABG values.
| Parameter | Interpretation |
|---|---|
| pH | < 7.35: acidosis; > 7.45: alkalosis |
| PaO2 | Low: hypoxemia; High: hyperoxemia |
| PaCO2 | High: respiratory acidosis; Low: respiratory alkalosis |
| HCO3- | High: metabolic alkalosis; Low: metabolic acidosis |
| SaO2 | < 95%: hypoxemia |
Prioritizing Patient Care
By recognizing cues, nurses are able to identify patients who are at risk for clinical deterioration and prioritize their care. Prioritization of patient care revolves around ensuring patient safety. If a patient is currently stable but demonstrating cues of a worsening clinical status, the nurse must prioritize that patient. Prioritization of patient care includes monitoring the patient more frequently, sending labs to follow a concerning trend, addressing complaints of pain, and addressing any other changes in clinical status (Déry et al., 2019).
Potential versus Actual Problems
The importance of recognizing cues cannot be understated. Recognizing cues of possible clinical deterioration and intervening early prevents a potential problem from becoming an actual problem. Consider the following example: A patient is dehydrated and presents with no urine output for more than eight hours. Routine laboratory studies show that the patient has mild metabolic acidosis and a serum potassium of 5.2 mEq/L. At the time the patient presents for medical care, they have an actual problem of dehydration and low urine output. However, if the low urine output and elevated potassium level are not addressed, then the patient is at risk of developing hyperkalemia with associated cardiac arrhythmias. In this situation, it is imperative the nurse recognize the cue of possible future deterioration given the fact that the patient has inadequate urine output and a slightly elevated serum potassium level.
Impact on Other Areas of Functioning
Fluid, electrolyte, and acid-base imbalances can impact other areas of functioning. The human body has mechanisms in place to maintain homeostasis; however, those mechanisms only provide a solution in acute clinical situations. They do not prevent problems from developing if the patient has a chronic condition that affects fluid, electrolyte, or acid-base imbalances.
All areas of homeostasis are impacted by chronic conditions. For example, a patient with end-stage renal disease will have electrolyte abnormalities because the kidneys are unable to filter fluid and solutes normally. Patients with chronic fluid volume excess with edema will ultimately develop decreased mobility and impaired skin integrity, whereas patients with fluid volume deficit are at risk for orthostatic hypotension, dizziness, and electrolyte abnormalities resulting in chronic fatigue and mental confusion. Lastly, patients with chronic acid-base imbalances develop alternation in the regulatory system that counterbalances the root cause of their imbalance. For example, a patient with chronic metabolic alkalosis will develop a lower respiratory rate to retain more carbon dioxide and offset the alkalosis.
Preventing Fluid, Electrolyte, and Acid-Base Imbalances
The keys to preventing fluid, electrolyte, and acid-base imbalances are recognizing which patients are at risk for those imbalances, screening for abnormalities, and intervening early if there are indications of a problem. Young children and older adults are at an increased risk for these imbalances because of their metabolic rates, ratio of fluid-to-body surface area, and increased risk of organ dysfunction related to their age. Also, certain medical conditions such as cancer, cardiovascular disease, and kidney disease place patients at an increased risk for developing an imbalance. Patients with known risk factors should have routine laboratory work done to screen for abnormalities. Intervening early can prevent more serious complications (Shrimanker & Bhattarai, 2023).
Nursing Interventions
Nursing interventions for patients who have a fluid, electrolyte, or acid-base imbalance depend on the abnormality being treated and the root cause of the problem identified. Nursing interventions include education about diet modifications, monitoring the patient’s vital signs and weight, reviewing laboratory values, adjusting the patient’s respiratory support, and administering medications and intravenous fluids. Specific examples of appropriate nursing interventions for different diagnoses may include the following:
- Electrolyte and fluid volume excess secondary to chronic kidney disease:
- developing a dietary plan
- educating the patient about which foods to avoid or minimize
- recommending a daily fluid intake
- monitoring the patient’s weight
- reviewing laboratory values
- Respiratory acidosis secondary to an acute illness:
- sending and reviewing serial ABG samples
- making adjustments to the patient’s respiratory support according to the ABG result
- Electrolyte and fluid volume deficit secondary to diarrhea:
- sending and reviewing chemistry analysis to evaluate electrolytes and renal function
- infusing intravenous fluids (IVFs) to correct fluid volume deficit
- making recommendations to adjust IVFs based on laboratory results
- monitoring patient’s vital signs and weight
Age-Related Considerations
Both older adults and young children are at higher risk for fluid, electrolyte imbalances, and acid-base imbalances. Patients in both age groups require more monitoring to enable nurses and other healthcare professionals to intervene early if an imbalance develops. Young children under the age of two are at an increased risk for imbalances because they have a higher metabolic rate, an increased rate of insensible fluid losses, and an inability to communicate their needs. Young children also have an immature immune system and are more prone to gastrointestinal illnesses that cause fluid loss (Vega & Avva, 2024). On the other hand, older adults are at increased risk for electrolyte and acid-base imbalances secondary to chronic disease, medication use, and decreased muscle mass that can impair breathing.
Life-Stage Context
Electrolyte and Fluid Balance in Older Adults
Older adults’ risk for dehydration is multifactorial. For many it is related to a decreased thirst sensation. Older adults are also more likely to be disabled or experience cognitive impairment, such as dementia or delirium, and forget to drink adequate water (Li et al., 2023). Furthermore, many older adults take medications, such as diuretics, that increase their fluid loss or affect their judgement (Masot et al., 2018).
Patient Education
Patient education is an important factor in preventing fluid, electrolyte, and acid-base imbalances. Many patients who develop an imbalance have risk factors. Identifying those risk factors and providing anticipatory guidance helps prevent complications.
For example, nurses play a crucial role in educating older adults and the parents of young children about the increased risk of fluid and electrolyte imbalances in these age groups. Nurses also play a pivotal role in making sure that patients who are taking medications that could cause an imbalance know what side effects to look for and when to seek medical attention. Patients with chronic disease such as congestive heart failure, renal disease, or COPD need to understand how their chronic illness affects fluid, electrolyte, and acid-base imbalances.
Patient Conversations
What If Your Patient Is Reluctant to Go to the Emergency Department for an Evaluation?
Scenario: A telephone triage nurse at an outpatient pediatrician’s office takes a phone call from a mother requesting an order for rectal Zofran to help her daughter stop vomiting.
Nurse: Thank you for calling Dr. Smith’s after-hours line. My name is Serena, I’m a registered nurse, and this is a recorded line. How can I help you?
Patient: Hi, Serena. My name is Heidi; I’m Eleni Papadopoulos’s mom. She has been vomiting nonstop all day. I can’t even get her to hold down sips of water. When my son was her age, the doctor gave me a prescription for Zofran and that really helped. Can the doctor call something like that in for me tonight?
Nurse: I’m sorry to hear Eleni isn’t feeling well. Before we jump to prescribing a medication, I’d like to get some more information from you. Can you tell me Eleni’s date of birth so that I can look up her chart?
Patient: Sure. It’s 2/4/2022.
Nurse: Great. I found her chart. It looks like she’s been healthy, no major illness or past medical history. How long has she been vomiting? Are there any other symptoms such as a fever or diarrhea?
Patient: She woke up around midnight vomiting and has been vomiting off and on for the past twelve hours. At first, she was only vomiting food, but for the past five or six hours I can’t get her to keep anything down. She spiked a temperature up to 103°F (39.4°C). I gave a dose of Motrin three hours ago and her temperature has come down a little. Now she’s grabbing her stomach and crying and won’t let me give her anything to eat or drink.
Nurse: I see. Abdominal pain, fever, and vomiting could be a lot of different things. Because of her age she’s at risk for dehydration and could get worse quickly. Because it is after our office hours, it is best for you to take her to the emergency department so she can be seen by a provider who can figure out what is going on.
Patient: I know it’s nothing serious. If I could just get her to stop vomiting, I’m sure she would be fine. Can’t you page the on-call provider and ask for a prescription?
Nurse: Your daughter’s symptoms concern me. It is best for her to be seen in the emergency department. She could have a serious infection that requires antibiotics. Also, she’s at risk for dehydration and may need intravenous fluid.
Patient: This is ridiculous! She’s just got a stomach bug. I can’t afford an emergency room visit for something as simple as a stomach bug.
Nurse: It may be a stomach bug; however, it could also be something more serious. Children under the age of 2 can get behind on their fluid intake and get sick quickly. What you are describing to me sounds serious. If she’s not taking any fluids by mouth, she could easily need IV fluids to get through this illness. I strongly encourage you to take her to the emergency department. Zofran is not a magic pill that will make her feel better. Something has triggered the fever, abdominal pain, and vomiting, and she needs to see a provider to get checked out.
Patient: I see. I certainly don’t want her to get any worse. I’ll get her ready and take her in.
Nurse: I’m glad to hear that. I’ll let the on-call provider know that you’re on the way to the emergency department so they can follow up with the emergency room provider. I hope she feels better soon.
Evaluation of Outcomes
Evaluation of patient outcomes is a critical step in providing optimal patient care. To successfully measure patient outcomes, the nurse must set measurable goals that can be met within a specific time frame. Once a goal, or outcome, has been established, evaluation of the outcome requires critical thinking by the nurse. The nurse must analyze the reassessment data and determine if the expected outcome was met. If the expected outcome was not met or was only partially met, the nurse needs to modify the nursing intervention in order to meet the patient’s clinical goals. Having measurable outcomes and analyzing those outcomes improves patient care and ensures the patient’s clinical goals are being met (Rørtveit et al., 2020).
Examples of measurable goals for patients at risk for fluid, electrolyte, or acid-base imbalances include the following:
- Patient will have a net even fluid balance within the next twelve hours.
- Patient’s serum sodium level will increase by 1 mEq/L every eight hours until within normal limits.
- Patient’s PaCO2 will increase by 5 mm Hg within the next two hours.
- Patient will decrease sodium intake by 50 percent within the next two weeks.