Volume depletion in adults

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

ACUTE

haemorrhagic losses

1st line – intravenous isotonic crystalloid

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1st line –

intravenous isotonic crystalloid

Initial choice for volume expansion.

In clinically stable patients with no evidence of active bleeding, replacement of lost plasma with crystalloid can be done while monitoring to verify no further significant drop in haematocrit.

The goal of fluid replacement is to restore haemodynamic stability and avoid shock and organ ischaemia. Fluid may be delivered as rapidly infused boluses of 250 to 500 mL, repeated as necessary. As it is extremely difficult to estimate the true volume deficit accurately, frequent monitoring of vital signs (particularly systolic blood pressure) is used to determine when adequate fluid replacement has been administered.

Plus – packed red blood cells

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Plus –

packed red blood cells

Treatment recommended for ALL patients in selected patient group

Blood is the definitive intravascular volume expander, and is particularly important in the setting of anaemia from acute blood loss.

A unit of packed red blood cells comprises 300 to 400 mL in total volume. It is common to begin with a transfusion of 2 units of packed red blood cells and monitor patient response.

Without ongoing blood loss, 1 unit of blood raises the haemoglobin concentration in the average adult by 1 g/dL.[43]

Consider – fresh frozen plasma

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Consider –

fresh frozen plasma

Additional treatment recommended for SOME patients in selected patient group

Fresh frozen plasma (FFP) contains physiological amounts of active plasma proteins.

It is used in settings of coagulopathy or factor deficiency to replace missing clotting factors and achieve haemostasis.

In massively transfused patients, the concentration of clotting factors is decreased because much of the patient's blood volume has been replaced by transfused blood.[44] Therefore, to compensate for this effect, 1 to 2 units of FFP are generally transfused for every 10 units of packed red blood cells.

Consider – treatment of source of bleeding

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Consider –

treatment of source of bleeding

Additional treatment recommended for SOME patients in selected patient group

When volume depletion due to haemorrhage is mild, typically the aetiology is self-limiting and does not require intervention to stop the bleeding.

However, consideration should be given to treatment of any underlying or contributory factors, to prevent further episodes.

The role of volume expansion in acute haemorrhage is to stabilise the patient while efforts are made to identify and treat the bleeding source.

In gastrointestinal (GI) bleeding, an endoscopy is generally necessary for diagnosis and treatment. In an upper GI bleed, such as from a gastric ulcer, oesophagogastroduodenoscopy provides an opportunity to examine the stomach and to intervene if bleeding has not stopped. In a lower GI bleed, such as a diverticular bleed, a colonoscopy is indicated.

In trauma or a possible bleeding aortic aneurysm, with suspected intra-abdominal or retroperitoneal bleeding, CT scanning followed by laparotomy or other surgical intervention may be necessary to identify and stop the haemorrhage.

gastrointestinal non-haemorrhagic losses: vomiting and/or diarrhoea

mild

1st line – oral replacement solutions

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1st line –

oral replacement solutions

In cases of mild volume depletion (e.g., if there are minimal symptoms on standing; no orthostatic hypotension; no signs of systemic hypoperfusion; tachycardia; and vomiting and diarrhoea are absent or controllable), treatment with oral replacement solutions can be attempted initially.

Sodium chloride tablets and electrolyte-containing solutions can be used. Glucose is typically added to these oral replacement solutions to promote uptake of sodium via the intestinal sodium/glucose co-transporter mechanism.

Solutions that are rice-based are effective in cholera, given the absorption of both protein and glucose that occurs with rice digestion.[7]

Oral solutions are the treatment of choice in developing countries for diarrhoeal illnesses, due to the lack of access to intravenous therapy.

Paediatric electrolyte solutions are used in children, particularly with gastroenteritis. These products contain sodium, potassium, chloride, citrate, and dextrose, and are designed to replace the solute and water that is lost with vomiting or diarrhoea.[36]

Consider – intravenous isotonic crystalloid

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Consider –

intravenous isotonic crystalloid

Additional treatment recommended for SOME patients in selected patient group

Isotonic crystalloid is the best initial choice for volume expansion.

If symptoms and vital signs do not respond adequately to oral replacement or the patient cannot tolerate oral replacement due to persistent vomiting, intravenous replacement is necessary.

Certain patient groups (e.g., young adults) may be able to compensate well and so initially appear only mildly volume-depleted. However, they may, in fact, have more deficit than clinically estimated.

Most patients will respond quickly to intravenous fluid resuscitation in this setting.

If there is continued nausea and vomiting on presentation despite only mild signs of volume depletion, intravenous saline is the most appropriate initial choice for resuscitation.

Consider – anti-emetics or antidiarrhoeals

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Consider –

anti-emetics or antidiarrhoeals

Additional treatment recommended for SOME patients in selected patient group

Promethazine, dosed orally or rectally, can be given for nausea and vomiting.

Oral metoclopramide may also be used. Metoclopramide should be used for up to 5 days only, in order to minimise the risk of neurological and other adverse effects.[45]

Orally administered ondansetron is also suitable in this setting.

Intravenous promethazine, ondansetron, or related drugs can be used in the emergency department, or in cases of continued vomiting.

Antidiarrhoeals, such as diphenoxylate/atropine or loperamide, can be given in cases of non-infectious diarrhoea.

Primary options

promethazine: 25 mg orally/rectally/intravenously every 6-8 hours when required

metoclopramide: 5-10 mg orally every 8 hours when required for a maximum of 5 days, maximum 30 mg/day

ondansetron: 8 mg orally/intravenously every 8 hours when required

diphenoxylate/atropine: 2.5 to 5 mg orally two to four times daily when required, maximum 20 mg/day

loperamide: 4 mg orally initially, followed by 2 mg orally after each loose stool when required, maximum 16 mg/day

moderate to severe

1st line – intravenous isotonic crystalloid for initial volume resuscitation

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1st line –

intravenous isotonic crystalloid for initial volume resuscitation

In moderate to severe cases of volume depletion (e.g., orthostatic hypotension is usually present with haemodynamic instability and there may be signs of systemic hypoperfusion and organ ischaemia), oral replacement solutions are not adequate to replace lost volume.

These patients often require hospitalisation for monitoring during resuscitation, or at least close and protracted monitoring in an emergency department setting.

Litres of fluid may be required, but stabilisation is usually easily achieved in these patients.

Consider – intravenous hypotonic saline (0.45% sodium chloride)

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Consider –

intravenous hypotonic saline (0.45% sodium chloride)

Additional treatment recommended for SOME patients in selected patient group

Once the initial volume deficit is replaced with isotonic crystalloid, 0.45% sodium chloride is often used as a maintenance fluid.

Hypotonic saline has a concentration of 77 mmol (77 mEq) sodium per litre, and can be used when there is hypernatraemia and a water deficit greater than the solute deficit.

If the patient is severely hypernatraemic (>160 mmol/l [>160 mEq/L]) and volume-depleted, isotonic crystalloid may still be preferred initially, because the volume deficit is more immediately life-threatening.[5][9]

Consider – anti-emetics

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Consider –

anti-emetics

Additional treatment recommended for SOME patients in selected patient group

Intravenous promethazine, metoclopramide, or ondansetron are very helpful in this situation. Metoclopramide should be used for up to 5 days only, in order to minimise the risk of neurological and other adverse effects.[45]

Primary options

promethazine: 25 mg intravenously every 6-8 hours when required

metoclopramide: 5-10 mg intravenously/intramuscularly every 8 hours when required for a maximum of 5 days, maximum 30 mg/day

ondansetron: 8 mg intravenously every 8 hours when required

Consider – intravenous isotonic sodium bicarbonate

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Consider –

intravenous isotonic sodium bicarbonate

Additional treatment recommended for SOME patients in selected patient group

An argument can be made for the use of sodium bicarbonate in settings of volume depletion and metabolic acidosis. However, without knowledge of the lab results, intravenous isotonic crystalloid is still the preferred initial choice for volume resuscitation.

The use of bicarbonate in anion gap acidosis such as lactic acidosis has been challenged, as its administration could increase intracellular acidosis and lactate production, and impair tissue oxygen delivery.[46]

Repeated administration of hypertonic ampoules will lead to hypernatraemia, a problem that can be avoided by using an isotonic sodium bicarbonate infusion.

Consider – intravenous vasopressors

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Consider –

intravenous vasopressors

Additional treatment recommended for SOME patients in selected patient group

In general, intravenous vasopressors are not indicated in shock due to gastrointestinal losses, as saline resuscitation is the appropriate treatment. However, if sepsis is suspected, vasopressors may be necessary.

The point at which vasopressors are instituted will depend on the exact clinical situation. Sepsis patients may require up to 10 L of intravenous fluids initially as resuscitation, whereas only 1-2 L may be required in cases of diarrhoeal losses. In general, up to 10 L of normal saline as 1 L boluses may be administered, with reassessment after each bolus to evaluate response and ensure that there are no signs of volume overload. If systolic blood pressure (SBP) does not increase to >100 mmHg following this approach, then vasopressors should be added.

If SBP is <60 mmHg at the initial evaluation of the patient, boluses of saline alone are unlikely to be sufficient to prevent ischaemia, so vasopressors should be used in conjunction with saline from the outset in this situation.

Primary options

noradrenaline (norepinephrine): 0.5 to 1 micrograms/minute intravenously, titrate according to response, maximum 30 micrograms/minute

2nd line – intravenous lactated Ringer's solution

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2nd line –

intravenous lactated Ringer's solution

Lactated Ringer's solution contains 130 mmol/L (130 mEq/L) sodium, 28 mmol/L (28 mEq/L) lactate, 4 mmol/L (4 mEq/L) potassium, as well as calcium and chloride, and can expand the intravascular space, but generally isotonic saline is preferred.

Lactate is converted to bicarbonate, which can be helpful in metabolic acidosis, but in lactic acidosis and liver disease this conversion is impaired, so lactate-containing fluids should be avoided in these circumstances.

In renal failure, the use of lactated Ringer's solution can contribute to hyperkalaemia.[5]

Consider – anti-emetics

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Consider –

anti-emetics

Additional treatment recommended for SOME patients in selected patient group

Primary options

promethazine: 25 mg intravenously every 6-8 hours when required

metoclopramide: 5-10 mg intravenously/intramuscularly every 8 hours when required for a maximum of 5 days, maximum 30 mg/day

ondansetron: 8 mg intravenously every 8 hours when required

Consider – intravenous isotonic sodium bicarbonate

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Consider –

intravenous isotonic sodium bicarbonate

Additional treatment recommended for SOME patients in selected patient group

The use of bicarbonate in anion gap acidosis such as lactic acidosis is controversial, as its administration can increase intracellular acidosis and lactate production, and impair tissue oxygen delivery.[46]

Repeated administration of hypertonic ampoules will lead to hypernatraemia, a problem that can be avoided by using an isotonic sodium bicarbonate infusion.

Consider – intravenous vasopressors

Back

Consider –

intravenous vasopressors

Additional treatment recommended for SOME patients in selected patient group

Primary options

noradrenaline (norepinephrine): 0.5 to 1 micrograms/minute intravenously, titrate according to response, maximum 30 micrograms/minute

excessive diuresis

1st line – assessment for withholding of any diuretics

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1st line –

assessment for withholding of any diuretics

Consideration should be made for modification or withholding of any diuretics being used.

Plus – oral replacement solutions

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Plus –

oral replacement solutions

Treatment recommended for ALL patients in selected patient group

Oral replacement is appropriate if it is possible to maintain oral intake to match the renal losses without a resulting electrolyte abnormality or haemodynamic instability.

Consider – intravenous fluids

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Consider –

intravenous fluids

Additional treatment recommended for SOME patients in selected patient group

Isotonic crystalloid is the best initial choice for volume expansion when needed.

In addition to overuse of diuretics, osmotic diuresis is also caused by glycosuria due to uncontrolled diabetes; by adrenal insufficiency; or rarely by salt-wasting nephropathies.

Renal water excretion can be severe in the setting of diabetes insipidus, but this primarily causes dehydration and hypernatraemia.[1][5][8][9]

The type of crystalloid solution required will depend on the electrolyte abnormalities detected by laboratory testing. Generally, isotonic crystalloid is the first line. However, if significant hypernatraemia is present, 0.45% normal saline may be appropriate to replace the water deficit as well. As dehydration and volume depletion may occur together, 0.45% saline allows for replacement of both solute and free water loss.

skin losses

burns

1st line – intravenous isotonic crystalloid

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1st line –

intravenous isotonic crystalloid

Isotonic crystalloid will best replace the fluid that is lost through burnt skin.

The volume deficit can be many litres in severe burns covering a large surface area. The Parkland formula aims to calculate the fluid resuscitation requirement in the first 24 hours, using the formula (4 mL x bodyweight in kg x % total body surface area burn), with half the calculated volume given in the first 8 hours and the other half given over the remaining 16 hours. However, close attention should also be given to monitoring urine output per hour, and resuscitation adjusted accordingly to maintain an output of 0.5 to 1 mL/kg/hr.

Close monitoring of vital signs is necessary, however, given the potential for over-resuscitation in burn patients. Too much fluid can lead to increased intra-abdominal pressure and compartment syndromes.[42]

Plus – treatment of burns: artificial skin or allografts

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Plus –

treatment of burns: artificial skin or allografts

Treatment recommended for ALL patients in selected patient group

Referral to a specialist burn centre is necessary if the burn is severe and covers a large surface area. There, definitive treatment such as debridement, wound dressing, and topical antibiotics will be used appropriately.

Ultimately skin grafts can be done to cover damaged areas with exposed tissue for cosmetic purposes, as well as to limit the potential for continued fluid loss.

profound sweating

1st line – oral replacement solutions or intravenous fluids

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1st line –

oral replacement solutions or intravenous fluids

When there has been excessive sweating but systolic blood pressure (SBP) remains >100 mmHg and pulse <100 bpm, it is reasonable to use oral replacement solutions or intravenous 0.45% sodium chloride. Sweat contains less solute than the fluid lost through burns, and, therefore, in less severe cases the deficit can be replaced with a hypotonic solution.

However, in more severe situations, with SBP <100 mmHg and/or pulse >100 bpm, isotonic crystalloid is the preferred initial choice; hypotonic saline or oral replacement solutions can then be used once the vital signs improve and patients are haemodynamically stable. When volume loss from excessive sweating is severe and leads to hypotension (SBP <100 mmHg) with symptoms such as confusion, isotonic saline should be used.

As in other states of moderate to severe volume depletion, the best choice is the fluid that will expand the intravascular space.

Even if there is a component of hypernatraemia from dehydration, when volume depletion exists, isotonic saline should be used.

It is rare to see severe volume depletion and hypotension from sweating alone.

third-space sequestration

1st line – intravenous isotonic saline

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1st line –

intravenous isotonic saline

Third-space sequestration is seen when abnormal collections of fluid develop in spaces where they cannot be re-absorbed into the intravascular space. Examples include ascites due to cirrhosis or Budd-Chiari syndrome, venous obstruction, severe pancreatitis, crush injury with muscle damage, and intestinal obstruction.[5][9]

The fluid is sequestered from the intravascular space, causing symptoms of volume depletion, so the resuscitation is an attempt to increase intravascular volume, and isotonic saline is the best choice.

Close monitoring of vital signs and response to resuscitation is important, as the deficit in third-space sequestration can be many litres. Care must be undertaken in certain situations, such as cirrhosis, when too much fluid can be detrimental.

Plus – management of underlying condition

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Plus –

management of underlying condition

Treatment recommended for ALL patients in selected patient group

Conservative management for bowel obstruction with nasogastric decompression is often initially attempted. However, in some patients, a surgical intervention is required to relieve the obstruction.

Obstruction of a large vein, such as the portal vein, can lead to ascites and fluid sequestration that may be difficult to manage. In some settings of venous obstruction, anticoagulants are used and the volume deficit replaced appropriately while waiting for response to anticoagulation.

Pancreatitis is generally managed with liberal use of isotonic crystalloid as needed for volume losses.

Orthopaedic consultation for measurement of compartment pressures and fasciotomy, if indicated, should be considered for crush injury.

pulmonary losses: bronchorrhoea or draining pleural effusion

1st line – intravenous isotonic saline

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1st line –

intravenous isotonic saline

Bronchorrhoea (i.e., excessive discharge of mucus from the bronchi) or draining pleural effusion are rare causes for volume depletion, but may be seen in chronically ill or hospitalised patients.

Symptoms are a reflection of intravascular volume depletion, so the intravascular space must be expanded with isotonic solution.

Plus – treatment of underlying condition

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Plus –

treatment of underlying condition

Treatment recommended for ALL patients in selected patient group

Pleurodesis may be necessary to limit continued drainage into the pleural space.

If bronchorrhoea is severe enough to lead to volume loss, appropriate treatment of the infection is necessary.

sustained inadequate oral intake

1st line – oral rehydration solutions

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1st line –

oral rehydration solutions

The inadequate oral intake must be recognised and vital signs and symptoms of volume depletion monitored closely.

This is generally seen in infants and in older people with limited ability to communicate thirst.

Sodium chloride tablets and electrolyte-containing solutions can be used. Glucose is typically added to oral replacement solutions to promote uptake of sodium via the intestinal sodium/glucose co-transporter mechanism.

Consider – intravenous fluids

Back

Consider –

intravenous fluids

Additional treatment recommended for SOME patients in selected patient group

Isotonic crystalloid is the best initial choice for volume expansion.

The goal of fluid replacement is to restore haemodynamic stability and avoid shock and organ ischaemia. Fluid is typically delivered as boluses of 250 to 500 mL of crystalloid, repeated as necessary. As it is extremely difficult to estimate the true volume deficit accurately, frequent monitoring of vital signs (particularly systolic blood pressure) is used to determine when adequate fluid replacement has been administered.

Once the volume deficit is replenished with isotonic saline, 0.45% normal saline can be used as a maintenance fluid.

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Volume depletion in adults

Treatment algorithm

haemorrhagic losses

intravenous isotonic crystalloid

packed red blood cells

fresh frozen plasma

treatment of source of bleeding

gastrointestinal non-haemorrhagic losses: vomiting and/or diarrhoea

oral replacement solutions

intravenous isotonic crystalloid

anti-emetics or antidiarrhoeals

Primary options

intravenous isotonic crystalloid for initial volume resuscitation

intravenous hypotonic saline (0.45% sodium chloride)

anti-emetics

Primary options

intravenous isotonic sodium bicarbonate

intravenous vasopressors

Primary options

intravenous lactated Ringer's solution

anti-emetics

Primary options

intravenous isotonic sodium bicarbonate

intravenous vasopressors

Primary options

excessive diuresis

assessment for withholding of any diuretics

oral replacement solutions

intravenous fluids

skin losses

intravenous isotonic crystalloid

treatment of burns: artificial skin or allografts

oral replacement solutions or intravenous fluids

third-space sequestration

intravenous isotonic saline

management of underlying condition

pulmonary losses: bronchorrhoea or draining pleural effusion

intravenous isotonic saline

treatment of underlying condition

sustained inadequate oral intake

oral rehydration solutions

intravenous fluids