Hypovolemia

Why are colloids better volume expanders?

Because they remain in the intravascular space longer than crystalloids

Which term refers to elevated plasma sodium and osmolality?

Dehydration

Describe the distribution of D5W

Distributes throughout total body water and useful for intracellular volume loss (dehydration) Poor volume expander - very little remains in the intravascular space

Describe the distribution of NaCl

Distributes to the extacellular fluid

What is the suggested treatment option for moderate or severe hypovolemia with predominant dehydation?

IV therapy with D5W

What is the suggested treatment option for moderate or severe hypovolemia with predominant volume depletion (postural tachycardia +/- postural fall of systolic pressure?

NaCl (NS) If severe, colloid solutions (e.g. albumins, starch compounds)

What is the suggested treatment option for mild hypovolemia (<5% of body weight)

Oral fluids

What physical manifestations/lab tests would indicate the severity of hypovolemia?

Tachycardia of more than 30 beats/min after 1 min of standing from recumbent position - most accurate sign of volume depletion. Postural decline of systolic pressure more than 20mm Hg Low JVP suggests volume depletion Hematocrit, albumin, urea increases Urine volume < 0.5mL/kg/hr

Define hypovolemia

generic term encompassing volume depletion and dehydration

Define volume depletion

loss of both Na+ and Water from the intravascular space

Define dehydration

loss of water from the extracellular and intracellular space