CNSC Exam - Fluid & Electrolytes
Exam QUESTIONS & ANSWERS BEST
EXAM SOLUTION LATEST UPDATE
2025/2026 RATED A+
Total body water percent of infants - CORRECT ANSWERS 75-80% lean body mass
Total body water percent of adults - CORRECT ANSWERS 60% lean body mass (males), 50% lean
body mass (females)
Total body water percent of older adults - CORRECT ANSWERS 50% lean body mass (males),
45% lean body mass (females)
Water content of muscle mass - CORRECT ANSWERS 75-80%
Primary sources of insensible gains - CORRECT ANSWERS Water oxidation
Primary sources of sensible losses - CORRECT ANSWERS Urine, GI output
Primary sources of insensible losses - CORRECT ANSWERS Lungs, skin
Average daily water gain - CORRECT ANSWERS 1500-2500 mL
Average daily water loss - CORRECT ANSWERS 1500-2500 mL
Type of losses dependent on the external environment - CORRECT ANSWERS Insensible losses
,Fluid requirements for <10 kg - CORRECT ANSWERS 100 mL/kg
Fluid requirements for 10-20 kg - CORRECT ANSWERS 1000 mL + 50 mL/kg for each kg b/w 10-
20 kg
Fluid requirements for 20+ kg (ages </= 50 yrs) - CORRECT ANSWERS 1500 mL + 20 mL/kg for
each kg above 20 kg
Fluid requirements for 20+ kg (ages >50 yrs) - CORRECT ANSWERS 1500 mL + 15 mL/kg for each
kg above 20 kg
Fluid requirements by age - CORRECT ANSWERS 18-55 years: 35 mL/kg
56-75 years: 30 mL/kg
75+ years: 25 mL/kg
Fluid restriction: </= 25 mL/kg
Factors that increase fluid needs - CORRECT ANSWERS Fever, emesis/NG output, diarrhea,
ostomy/fistula output, hyperventilation, excessive sweating, burn injury, prematurity
How many extra fluids are needed for fever? - CORRECT ANSWERS Increase by 12.5% for each 1
degree C above normal
Factors that decrease fluid needs - CORRECT ANSWERS Fluid overload, heart failure, renal
failure, SIADH, ascites, anasarca
How many mL fluid to add for insensible losses when estimating IVF needs? - CORRECT ANSWERS
500 mL
, Markers of fluid deficit - CORRECT ANSWERS Decreased skin turgor, dry mucous membrane, wt
loss, sunken eyes, orthostasis, oliguria, elevated hematocrit, elevate urine specific gravity, urine Na <20
mEq/L
BUN:Cr ratio associated with fluid deficit - CORRECT ANSWERS BUN:Cr >15
Markers of fluid overload - CORRECT ANSWERS Edema, ascites, wt gain, crackles on chest
auscultation, pulmonary edema, elevated jugular venous pressure
Crystalloid fluids - CORRECT ANSWERS Fluids that contain primarily electrolytes and differ
based on solution tonicity
Colloid fluids - CORRECT ANSWERS Fluids containing larger particles like proteins; primarily
given as resuscitation fluids
Osmotic pressure - CORRECT ANSWERS Pressure that drives water movement from areas of low
to high solute concentration
Oncotic pressure - CORRECT ANSWERS Force exerted by proteins that draw water into blood
vessels
Plasma solute concentrations - CORRECT ANSWERS 140 mEq/L Na, 103 mEq/L Cl, 4 mEq/L K, 5
mEq/L Ca, 2 mEq/L Mg, bicarb
D5W solute concentrations - CORRECT ANSWERS No electrolytes, 5% dextrose
0.9% NaCl solute concentrations - CORRECT ANSWERS 154 mEq/L Na, 154 mEq/L Cl
1/2 NS solute concentrations - CORRECT ANSWERS 77 mEq/L Na, 77 mEq/L Cl
Exam QUESTIONS & ANSWERS BEST
EXAM SOLUTION LATEST UPDATE
2025/2026 RATED A+
Total body water percent of infants - CORRECT ANSWERS 75-80% lean body mass
Total body water percent of adults - CORRECT ANSWERS 60% lean body mass (males), 50% lean
body mass (females)
Total body water percent of older adults - CORRECT ANSWERS 50% lean body mass (males),
45% lean body mass (females)
Water content of muscle mass - CORRECT ANSWERS 75-80%
Primary sources of insensible gains - CORRECT ANSWERS Water oxidation
Primary sources of sensible losses - CORRECT ANSWERS Urine, GI output
Primary sources of insensible losses - CORRECT ANSWERS Lungs, skin
Average daily water gain - CORRECT ANSWERS 1500-2500 mL
Average daily water loss - CORRECT ANSWERS 1500-2500 mL
Type of losses dependent on the external environment - CORRECT ANSWERS Insensible losses
,Fluid requirements for <10 kg - CORRECT ANSWERS 100 mL/kg
Fluid requirements for 10-20 kg - CORRECT ANSWERS 1000 mL + 50 mL/kg for each kg b/w 10-
20 kg
Fluid requirements for 20+ kg (ages </= 50 yrs) - CORRECT ANSWERS 1500 mL + 20 mL/kg for
each kg above 20 kg
Fluid requirements for 20+ kg (ages >50 yrs) - CORRECT ANSWERS 1500 mL + 15 mL/kg for each
kg above 20 kg
Fluid requirements by age - CORRECT ANSWERS 18-55 years: 35 mL/kg
56-75 years: 30 mL/kg
75+ years: 25 mL/kg
Fluid restriction: </= 25 mL/kg
Factors that increase fluid needs - CORRECT ANSWERS Fever, emesis/NG output, diarrhea,
ostomy/fistula output, hyperventilation, excessive sweating, burn injury, prematurity
How many extra fluids are needed for fever? - CORRECT ANSWERS Increase by 12.5% for each 1
degree C above normal
Factors that decrease fluid needs - CORRECT ANSWERS Fluid overload, heart failure, renal
failure, SIADH, ascites, anasarca
How many mL fluid to add for insensible losses when estimating IVF needs? - CORRECT ANSWERS
500 mL
, Markers of fluid deficit - CORRECT ANSWERS Decreased skin turgor, dry mucous membrane, wt
loss, sunken eyes, orthostasis, oliguria, elevated hematocrit, elevate urine specific gravity, urine Na <20
mEq/L
BUN:Cr ratio associated with fluid deficit - CORRECT ANSWERS BUN:Cr >15
Markers of fluid overload - CORRECT ANSWERS Edema, ascites, wt gain, crackles on chest
auscultation, pulmonary edema, elevated jugular venous pressure
Crystalloid fluids - CORRECT ANSWERS Fluids that contain primarily electrolytes and differ
based on solution tonicity
Colloid fluids - CORRECT ANSWERS Fluids containing larger particles like proteins; primarily
given as resuscitation fluids
Osmotic pressure - CORRECT ANSWERS Pressure that drives water movement from areas of low
to high solute concentration
Oncotic pressure - CORRECT ANSWERS Force exerted by proteins that draw water into blood
vessels
Plasma solute concentrations - CORRECT ANSWERS 140 mEq/L Na, 103 mEq/L Cl, 4 mEq/L K, 5
mEq/L Ca, 2 mEq/L Mg, bicarb
D5W solute concentrations - CORRECT ANSWERS No electrolytes, 5% dextrose
0.9% NaCl solute concentrations - CORRECT ANSWERS 154 mEq/L Na, 154 mEq/L Cl
1/2 NS solute concentrations - CORRECT ANSWERS 77 mEq/L Na, 77 mEq/L Cl
