Fluid management

Question 1

What are the three main purposes of fluid prescription in hospitalized patients?

Answer 1

Resuscitation – Restore intravascular volume and improve perfusion.
Maintenance – Meet daily physiological needs when oral intake is insufficient.
Replacement – Compensate for ongoing or anticipated fluid losses.

Question 2

Name three key factors to consider before prescribing fluids.

Answer 2

Patient’s weight and size.
Presence of comorbidities (e.g., heart failure, CKD).
Reason for admission and clinical status.

Question 3

Why is fluid management particularly important in peri-operative care?

Answer 3

Proper fluid and haemodynamic management reduces post-operative morbidity and length of hospital stay.

Question 4

What proportion of total body weight is water?

Answer 4

Approximately 2/3 of total body weight is water.

Question 5

How is total body water distributed between intracellular and extracellular compartments?

Answer 5

2/3 intracellular.
1/3 extracellular (of which: 1/5 is intravascular, 4/5 is interstitial).

Question 6

Why do septic patients often require large volumes of IV fluids?

Answer 6

Sepsis increases vascular permeability, leading to fluid leakage into tissues. Large volumes are needed to maintain intravascular volume despite high total body water.

Question 7

According to NICE guidelines, what are the daily maintenance fluid requirements for a 70 kg adult?

Answer 7

Water: 1750 mL (25 mL/kg/day).
Sodium: 70 mmol (1 mmol/kg/day).
Potassium: 70 mmol (1 mmol/kg/day).
Glucose: 50 g/day.

Question 8

Outline a typical 24-hour maintenance fluid regimen for a 70 kg adult.

Answer 8

500 mL 0.9% saline with 20 mmol K+ over 8 hours.
1 L 5% dextrose with 20 mmol K+ over 8 hours.
500 mL 5% dextrose with 20 mmol K+ over 8 hours.

Question 9

How is fluid deficit commonly assessed in clinical practice?

Answer 9

Subjectively based on:

Clinical parameters (e.g., dry mucous membranes, low urine output).
Patient size and comorbidities.

Question 10

What urine output should trigger concern for fluid deficit in adults?

Answer 10

Urine output < 0.5 mL/kg/hour.

Question 11

Describe a typical fluid challenge in a patient with low urine output.

Answer 11

250–500 mL of IV fluid over 15–30 minutes, depending on patient size and comorbidities.

Question 12

What are some common causes of ongoing fluid losses?

Answer 12

Third-space losses (e.g., bowel obstruction, pancreatitis).
Diuresis.
Increased stool output (e.g., diarrhea, high stoma output).
Fever or tachypnoea increasing insensible losses.

Question 13

Which electrolyte abnormalities are commonly seen with vomiting?

Answer 13

Low potassium (K+).
Low chloride (Cl−).
Alkalosis.

Question 14

What clinical signs indicate fluid depletion?

Answer 14

Dry mucous membranes.
Reduced skin turgor.
Decreased urine output (< 0.5 mL/kg/hr).
Orthostatic hypotension.
Tachycardia and low blood pressure in severe cases.

Question 15

What are common signs of fluid overload?

Answer 15

Raised JVP.
Peripheral or sacral oedema.
Pulmonary oedema (e.g., crackles on auscultation).

Question 16

What tools should be used to monitor a patient’s fluid status?

Answer 16

Fluid input-output charts.
Daily weight charts.
Urea & Electrolytes (U&Es).

Question 17

What are the two main categories of IV fluids?

Answer 17

Crystalloids – e.g., 0.9% saline, Hartmann’s, 5% dextrose.
Colloids – e.g., albumin, gelatins (rarely used now).

Question 18

Why are crystalloids preferred over colloids for resuscitation?

Answer 18

Cheaper and widely available.
No significant clinical benefit of colloids over crystalloids.
Similar effectiveness in replenishing intravascular volume.

Question 19

What is the primary purpose of 5% dextrose?

Answer 19

To provide free water and glucose for metabolism, not for significant intravascular volume expansion.

Question 20

What is the composition of 0.9% saline?

Answer 20

Sodium: 154 mmol/L.
Chloride: 154 mmol/L.
No glucose.

Question 21

Why might a patient be kept ‘on the dry side’ post-operatively?

Answer 21

To reduce the risk of complications such as pulmonary oedema and wound dehiscence.

Question 22

Why is careful fluid management important in patients with heart failure or CKD?

Answer 22

These patients are at higher risk of fluid overload and electrolyte imbalances.

Question 23

What are the NICE guidelines for daily maintenance of water, sodium, potassium, and glucose?

Answer 23

Water: 25 mL/kg/day.
Sodium: 1 mmol/kg/day.
Potassium: 1 mmol/kg/day.
Glucose: 50 g/day.

Question 24

Why is it important to reassess fluid prescriptions regularly?

Answer 24

To adapt to the patient’s changing clinical condition.
To prevent complications like fluid overload or dehydration.