1 Fluid Balance and Assessment Free Online FlashCards

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

In a typical adult, total body water is roughly $50\text{–}60\%$ of body weight.

Which cations predominate in ECF and ICF?

Sodium is the major cation in ECF; potassium is the major cation in ICF.

How does water move across membranes?

Water moves across membranes by osmosis; solutes move by processes such as diffusion and active transport.

What sources should be considered when assessing fluid intake?

Count drinks, foods, enteral feeds, and prescribed IV fluids; include fluid in medications and blood products when relevant.

What mechanisms help regulate water and electrolyte balance?

The kidneys adjust water and electrolyte excretion. Thirst, antidiuretic hormone, and the renin–angiotensin–aldosterone system also help regulate fluid balance.

What findings may suggest a fluid deficit?

Possible deficit cues include thirst, dry mucous membranes, reduced or concentrated urine, tachycardia, weak pulse, delayed capillary refill, and orthostatic symptoms or hypotension.

Approximately how much water does a $1\,\text{kg}$ weight change represent?

A change of about $1\,\text{kg}$ in body weight corresponds approximately to $1\,\text{L}$ of water.

Why should fluid status be assessed using multiple findings together?

Interpret history, examination, intake and output, weight trends, vital signs, and laboratory results together and in clinical context; no single sign describes the whole fluid status.

What fraction of total body water is intracellular fluid?

Intracellular fluid $ICF$ makes up about $\frac{2}{3}$ of total body water.

What fraction of total body water is ECF, and what are its main subdivisions?

Extracellular fluid $ECF$ makes up about $\frac{1}{3}$ of total body water. It includes interstitial, intravascular, and smaller transcellular fluid volumes.

Which fluid losses are measurable, and where are less-measurable losses made?

Output includes urine, stool, emesis, drains, and other measurable losses. Water is also lost through the skin and lungs, where it is not readily measured.

What findings may suggest fluid excess?

Possible excess cues include peripheral or dependent edema, rapid weight gain, jugular venous distension, and pulmonary signs such as crackles or dyspnea.