• Use ABCDE approach
• Treat the cause of fluid deficit
• All resuscitation treatment is given as boluses of fluid in addition to, or before starting, maintenance fluids
• Continue prescribed maintenance fluid therapy concurrently with resuscitation therapy
• Use clinical assessment rather than cumulative maintenance volumes administered when predicting required resuscitation volume

Volume of initial fluid

• Assess. See table to assess fluid deficit (Open Table)

• In patients at risk of pulmonary oedema because of heart failure, reduce fluid bolus volume by half

Fluid deficit none/mild

• Encourage patient to drink and/or give patient fluids enterally – see Practice and ethics of nutritional support in medical patients guideline especially if any complex fluid or electrolyte problems. Otherwise, move to IV Maintenance Fluids guideline

Fluid deficit moderate

• 500 mL IV bolus over 15 min, then reassess

Fluid deficit severe

• 500 mL IV bolus over 10 min, then reassess

Fluid deficit critical/shock

• 1000 mL IV bolus over 5 min, then reassess

Choice of initial fluid

Sodium chloride 0.9%

• Severe vomiting
• Brain injury

Balanced crystalloid e.g. compound sodium lactate (Hartmann’s) solution

• Severe diarrhoea
• Gastrointestinal fistula
• Poor intake (many medical patients)
• Serum potassium ≤5.5 mmol
• Loss of fluid of plasma constituency or severe patient stress (majority of surgical patients) resulting from:
• blood loss
• surgery
• injury
• systemic inflammatory response
• burns
• increased insensible losses due to fever or environmental factors
• increased losses from respiratory tract in acute respiratory failure (includes acute severe asthma)
• epidural anaesthesia

Blood products

• Major haemorrhage
• Coagulopathy. Contact haematologist

• Never infuse fluids containing >5 mmol/L potassium rapidly
• Compound sodium lactate (Hartmann’s) contains 5 mmol/L and can, therefore, be infused rapidly
• If a patient requiring rapid fluid boluses for resuscitation is also hypokalaemic, prescribe potassium separately in their maintenance fluid regimen or, if hypokalaemia severe (serum potassium <3 mmol/L), follow Hypokalaemia guideline
• Consider using isotonic sodium bicarbonate in hyperkalaemia to encourage intracellular shift of potassium

Ask for expert review if in doubt and particularly if:

• Patient in shock/critical
• >2000 mL resuscitation fluid required in 1 hr, patient has signs of shock or there is doubt about requirement for continuing fluid resuscitation
• Renal failure suspected, discuss with critical care or renal physicians
• Risk of pulmonary oedema

• Reassess. See table to assess fluid deficit (Open Table)
• Manage continuing persistent fluid deficit with further fluid boluses as per Initial Management above
• Hourly urine output (renal failure likely if <0.5 mL/kg/hr)
• If >2000 mL required in 1 hr, patient has signs of shock or there is doubt about requirement for continuing fluid resuscitation, seek expert help
• If >4 L of fluid required in 24 hr or blood loss suspected, send repeat FBC, clotting screen and ensure group and save sample is in date or crossmatched blood is available

Signs of hypovolaemia do not resolve

• If patient shows only transient recovery despite fluid boluses totalling 2000 mL in 1 hr, (or 1000 mL in elderly patients), perform arterial blood gas analysis to detect metabolic acidosis secondary to inadequate tissue perfusion and/or endogenous catecholamines
• request senior review to consider referral to critical care, advice on specific treatment including possible insertion of central venous catheter

Signs of hypovolaemia resolve

• Commence or continue maintenance fluid regimen. See IV Maintenance Fluid guideline
• Reassess for clinical signs of hypovolaemia at 30 min intervals until signs of hypovolaemia have resolved for ≥2 hr and there are no signs of continuing losses
• a significant proportion of patients will have only a transient response to fluid bolus