Headache, confusion, lethargy; seizures under about 120
Fluid, Electrolyte & Acid-Base · Topic 7 of 23
Fluid Volume Excess / Overload
The patient gained 2 kg overnight with no dietary change — that's 2 liters of retained fluid, and the lungs are next in line to show it.
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Fluid volume overload
Na⁺SodiumPriority
K⁺PotassiumWNL
Cl⁻ChlorideWNL
Ca²⁺CalciumWNL
Mg²⁺MagnesiumWNL
PO₄³⁻PhosphateWNL
ECFVolume (ECF)H
pHpHWNL
Bedside monitor · pattern
Hyponatremia
Excess water relative to sodium lowers serum tonicity, so water moves into brain cells.
Direct physiology↓ serum tonicity→Water enters neurons→Cerebral edema
ECG responseNormal sinus rhythm
Neuronal excitabilityNormal
SuppressedBalancedHyper
PerfusionHypervolemic
116%+2.2 kg
Bibasilar crackles, dependent pitting edema, bounding pulse. Daily weights on the same scale at the same time — one kilogram is one litre.
What the nurse would notice
Hyponatremia across body systems
Also on this panel
Cramps, weakness, poor coordination
Nausea and vomiting with an acute fall
Concentrated urine if ADH is the cause
Teaching model, not a clinical calculator. Patterns show high-yield directional relationships under the stated assumption. Real symptoms, ranges and treatment depend on cause, acuity, comorbidities and local protocols.
Signs & symptoms
Present on this panel. Tap any sign to see which values produce it.
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Fluids & electrolytes · Volume
Fluid Volume Excess
Hypervolemia (too much fluid): the body keeps water and sodium together in the extracellular space. The scale shows how much — the lungs show how dangerous.
Example patient · heart failure · dry weight 80 kgAct now
Weight+2.0kg≈ 2.0 L kept
scale: 82.0 kg
scale: 82.0 kg
SpO₂89%goal: above 92%
Lungs wetFluid seeps into the air sacs themselves — less oxygen crosses into the blood
Nurse sees: Crackles, dyspnea, SpO₂ below 92%
NormalFluid
buildingLungs
wetPulmonary
edema
buildingLungs
wetPulmonary
edema
Sit up in high Fowler's and give oxygen to keep SpO₂ above 92%. Stop or slow the IV fluid and notify the provider — then give the ordered IV furosemide.
Illustration — one example patient. Weight can climb from edema alone; the lungs and SpO₂ show how dangerous it is.
01 · Daily weight1 kg ≈ 1 L
The most reliable fluid check · same time, same scale, same clothing
02 · The dangerPulmonary edema
Sudden dyspnea (short of breath), crackles, pink frothy sputum, SpO₂ below 92%
03 · The fixHigh Fowler's + oxygen
Sit upright, keep SpO₂ above 92% — then give the ordered IV furosemide (loop diuretic)
01
What causes it
Watch for#1 cause: heart failure
Body can't get rid of fluid
Heart failuremost commonKidney failureLiver cirrhosis
Too much going in
Too much IV fluidthe cause the nurse controlsToo much sodium or fluid intake
Drugs that make you hold fluid
NSAIDsCorticosteroidsEstrogenThiazolidinedionespioglitazone
Water and sodium are kept together, so the extra fluid stays outside the cells — in the vessels and tissues.
02
What you'll see
SignsWeight gain earlythe most reliable sign · 1 kg ≈ 1 L
Bounding pulse · hypertension (high BP)
JVD (jugular venous distension — bulging neck veins)
Dependent pitting edema (swelling that holds a dent)ankles when upright, sacrum in bed · graded 0 to 4+ by depth
Ascites (fluid in the belly)
Crackles · dyspnea (short of breath) latefluid has reached the lungs
Weight can climb from edema alone — confirm the lungs with lung sounds and SpO₂.
03
Labs & diagnostics
CheckLabs are diluted — the numbers fall
Hematocrit and hemoglobin fallthe same red cells in more water
BUN falls
Serum Na⁺ and osmolality may falldilutional hyponatremia
Daily weightsame time, same scale, same clothing · 1 kg ≈ 1 L
Lung sounds + pulse oximetry, oftenSpO₂ can drop before the patient says they're short of breath
04
Red flags
Act nowSudden dyspnea with crackles report nowacute pulmonary edema
Pink frothy sputum report now
SpO₂ below 92% report nowsit up + oxygen first
New crackles while IV fluid runs report nowstop or slow the infusion and notify the provider
Gain of 2 – 3 lb (about 1 kg) in a day report nowor 5 lb (about 2 kg) in a week
Low K⁺ on a loop diuretic report nowloop diuretics waste potassium
05
Treatment: breathe first, then pull the fluid off
Remove the extraAirway and oxygen first — then the diuretic
Do right now — trouble breathing
1
→Sit in high Fowler'supright so the lungs can expand
2
→Give oxygenkeep SpO₂ above 92%
3
→Stop or slow the IV fluidand notify the provider
4
Give the ordered IV furosemideloop diuretic — fluid off fast
Diureticpull the fluid off
Furosemide (loop diuretic)
IV when fluid must come off fast. Loop diuretics waste potassium.
Watch K⁺, BUN & creatinineRestrictfluid and sodium, as ordered
Heart failure: sodium under 2 g a day.
All liquids countOxygenprotect the lungs
High Fowler's + O₂ to keep SpO₂ above 92%.
SpO₂ can fall before dyspneaIs the diuretic working? Expect all four
More urine
Output rises
strict I&O
Weight down
Daily weight falls
1 kg ≈ 1 L off
Crackles clearing
Lungs quieter
listen after each dose
Breathing easier
Less dyspnea
SpO₂ back above 92%
More detail
Oral diuretics for milder overload
Dialysis for life-threatening overloadespecially with kidney failure
06
Nursing priorities
In orderBreathing first: high Fowler's + oxygenkeep SpO₂ above 92%
Lung sounds and SpO₂, oftenSpO₂ can drop before the patient reports shortness of breath
Stop or slow the IV fluid · notify the provider
Give the ordered diuretic — then check the responsemore urine, weight down, crackles clearing, breathing easier
Daily weight · strict I&Osame time, same scale, same clothing
Watch K⁺, BUN and creatinine on IV diureticsloop diuretics waste potassium
Restrict fluid and sodium as orderedheart failure: sodium under 2 g a day
07
Too much, too little — or in the wrong place?
| What happened | Too much fluid, kept in the vessels and tissues |
|---|---|
| Weight | Up |
| Pulse & BP | Bounding pulse · high BP |
| Neck & lungs | JVD, crackles |
| Labs | Diluted — Hct, BUN, Na⁺ fall |
| Fix | Loop diuretic + restrict fluid & sodium |
08
Teach your patient
DischargeWeigh every morningsame time, same scale, same clothing
Report a gain of 2 – 3 lb (about 1 kg) in a day or 5 lb (about 2 kg) in a week
Limit sodium and fluid as orderedheart failure: sodium under 2 g a day
Watch for swelling at homerings getting tight · socks leaving deep marks
Report new shortness of breath
Ask before taking NSAIDsNSAIDs, steroids and estrogen can make you hold fluid
The scale tells you how much — 1 kg ≈ 1 L. The lungs tell you how dangerous: crackles and a falling SpO₂ mean sit up, oxygen, then the diuretic.
Sources · OpenStax Medical-Surgical Nursing 10.2 (Fluid Disturbances), 12.3 (Heart Failure), OpenStax Pharmacology 19.1 (Heart Failure) and 5.1 (Fluid Volume), OpenStax Clinical Nursing Skills 19.2 and 19.3, the 0.9% sodium chloride label (DailyMed) and StatPearls: Hypovolemia. Diagram drawn from Alveolus diagram (LadyofHats, Wikimedia Commons, public domain) and Gas exchange in the alveolus (domdomegg, Wikimedia Commons, CC BY 4.0); lung locator from Lungs diagram simple (Patrick J. Lynch & C. Carl Jaffe, Wikimedia Commons, CC BY 2.5). Typical adult values — follow your protocol.
Fluid Volume Excess / Overload
The patient gained 2 kg overnight with no dietary change — that's 2 liters of retained fluid, and the lungs are next in line to show it.
Fluid volume excess (FVE) occurs when the body retains more isotonic fluid than it can excrete, expanding the extracellular compartment. The most common causes are heart failure, renal failure, liver cirrhosis, and excessive IV fluid administration. The key assessment finding is weight gain — 1 kg equals 1 liter of retained fluid. Daily weights are the single most reliable indicator, taken same time, same scale, same clothing. Lung sounds reveal the danger: crackles (rales) in the bases indicate pulmonary congestion. Other signs include bounding pulse, elevated BP, distended neck veins (JVD), peripheral edema (pitting, rated 1+ to 4+), and decreased hematocrit due to hemodilution. Intake and output monitoring is critical — output should roughly match intake. Nursing priorities include restricting fluids and sodium as ordered, positioning the patient in high Fowler's to ease breathing, monitoring respiratory status frequently, and administering prescribed diuretics. Oxygen saturation may drop before the patient reports dyspnea, so pulse oximetry catches deterioration early.
Key Distinctions
Don't confuse FVE (weight gain, bounding pulse, hypertension, hemodilution) with fluid volume deficit (weight loss, thready pulse, hypotension, hemoconcentration) — they mirror each other. Students often mistake edema from third-spacing for FVE; third-spacing moves fluid OUT of the vascular space causing intravascular depletion despite visible swelling. FVE labs show dilutional effects — low hematocrit — and serum sodium may drop in severe cases (dilutional hyponatremia), but in isotonic overload sodium can remain normal.
Clinical Pearl
Weight is the truth-teller. A gain of 1 kg overnight = 1 liter retained. If the scale goes up, the lungs are filling — listen before the patient gasps.
Knowledge Check
3 quick questions on the must-knows for this topic.
Question 1 of 3
Which lung sound indicates pulmonary congestion in fluid overload?
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Go further
- SimulatorFluid & Electrolyte SimulatorChange one lab. Watch the whole patient respond. Sodium, potassium, calcium, magnesium, pH and volume, all linked — with a live ECG and an IV pole where every bag runs.
- GuideFluid and Electrolyte NCLEX Questions: The 7 Patterns the Exam Keeps TestingThe priority is the organ, not the number. Anything changing the ECG comes first. Magnesium before potassium and calcium. Volume before the electrolyte. The lab that is lying. Slow is the rule for correction. The assessment that gates the drug. Learn the seven patterns and the individual questions stop being surprising.
- GuideHyperkalemia ECG Changes in Order: Peaked T Waves to Sine Wave, and What the Nurse Does FirstThe fixed sequence — peaked T, long PR, wide QRS, sine wave — with approximate potassium levels, what IV calcium actually does (protects the heart, does not lower the potassium), the stabilize–shift–eliminate treatment order, and what the nurse monitors. Includes a live ECG you can drag.
- SimulatorAcid–Base & ABG SimulatorBuild a gas. Watch compensation happen. Move CO₂ or bicarbonate, then read the gas in three calls: pH, cause, compensation.
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