3 Fluid Balance and Volume Disorders Free Online FlashCards

What proportion of a typical adult’s body weight is total body water?

In a typical adult, total body water is about $50\text{–}60\%$ of body weight, varying with age, body composition, and other factors.

How is total body water divided between ICF and ECF?

About $\frac{2}{3}$ of total body water is intracellular fluid $ICF$; the remaining $\frac{1}{3}$ is extracellular fluid $ECF$.

What are the two main components of ECF?

ECF includes interstitial fluid between cells and intravascular fluid within blood vessels, as well as smaller amounts in other spaces.

Which principal cations characterize ECF and ICF?

Sodium is the principal cation in ECF, while potassium is the principal cation in ICF.

Does visible edema prove that circulating volume is adequate?

No. Fluid can move from blood vessels into interstitial spaces, causing edema while effective circulating volume and perfusion remain reduced.

What are common sources of measurable fluid intake?

Measurable intake commonly includes drinks, liquid foods, enteral feeding, and intravenous fluids. Record amounts in milliliters according to facility rules.

What are common sources of measurable fluid output?

Common measurable outputs include urine, emesis, liquid stool, and measurable drainage from tubes or wounds.

What are insensible fluid losses, and what can increase them?

Sweat and water lost through breathing are insensible losses and are not routinely measured. Fever, heat, and rapid breathing can increase them.

Intake is $1{,}800\text{ mL}$ and measured output is $1{,}400\text{ mL}$. What is the balance?

The recorded balance is $1{,}800\text{ mL}-1{,}400\text{ mL}=+400\text{ mL}$, a net positive measured balance.

Does a measured fluid balance directly show a patient’s actual volume status?

No. Incomplete records and unmeasured losses can make the recorded balance differ from actual fluid change; it does not directly measure total-body or intravascular volume.

What urine-output rate is a warning finding?

Urine output below $0.5\text{ mL/kg/hour}$ is a warning finding, especially if sustained or accompanied by worsening perfusion. Interpret it in clinical context.

How should daily weights be compared when assessing fluid trends?

Use the same scale at a similar time, with similar clothing and conditions. An acute change of about $1\text{ kg}$ corresponds to about $1\text{ L}$ of water, though measurement conditions matter.