From the Guidelines
Hypovolemia is primarily caused by a significant loss of blood or fluids from the body, which can occur due to various factors such as hemorrhage, severe dehydration, burns, medical conditions, and certain medications. This condition occurs when there is a decrease in circulating blood volume, typically due to hemorrhage from trauma, surgery, or internal bleeding 1. Other common causes include severe dehydration from excessive vomiting, diarrhea, sweating, or inadequate fluid intake. Burns can lead to hypovolemia through fluid loss from damaged skin surfaces. Medical conditions like diabetic ketoacidosis cause fluid loss through excessive urination. Severe infections may trigger hypovolemia through increased vascular permeability, allowing fluid to leak into tissues. Certain medications, particularly diuretics, can contribute by increasing urine output. Adrenal insufficiency may cause hypovolemia due to impaired sodium retention.
Some key points to consider when evaluating the causes of hypovolemia include:
- The patient's ability to tolerate fluids varies and the same volume of fluid can have different clinical effects depending on acute and chronic comorbidities 1
- High-risk patients have lower fluid tolerance and are at higher risk of fluid accumulation 1
- Larger volumes of fluid might be needed to restore euvolaemia and tissue perfusion in patients with severe intravascular hypovolaemia 1
- Fluid therapy needs to be adjusted and individualised to keep the individual fluid status in the ‘green zone’, that is, in a state of intravascular euvolaemia 1
It is essential to note that the treatment of hypovolemia depends on the underlying cause but typically involves fluid replacement with intravenous solutions like normal saline or lactated Ringer's solution, administered at rates determined by the severity of volume depletion and the patient's cardiovascular status 1. Blood transfusions may be necessary for significant blood loss. Prompt recognition and treatment of hypovolemia are essential as severe cases can progress to hypovolemic shock, a life-threatening condition characterized by inadequate tissue perfusion and organ dysfunction 1.
From the Research
Causes of Hypovolemia
- Trauma is a common cause of hypovolemia, often resulting in profuse blood loss 2
- Dehydration is another frequent cause, primarily involving the loss of plasma rather than whole blood 2
- Hypovolemia can also occur due to excessive loss of fluids, such as vomiting and diarrhea, or inadequate intake of fluids, particularly in cancer patients 3
- Blood loss and the accumulation of fluid in injured tissue can lead to hemodynamic instability and hypovolemia in trauma patients 4
Associated Conditions
- Hypovolemia can lead to a range of complications, including reduction in circulating blood volume, lower venous return, and arterial hypotension 2
- Myocardial failure may result from increased myocardial oxygen demand in conjunction with reduced tissue perfusion 2
- Anaerobic metabolism due to reduced perfusion can produce acidosis and, together with myocardial dysfunction, precipitate multi-organ failure 2
- Dehydration can occur among patients who are hypervolemic, euvolemic, or hypovolemic, and cancer patients are more often hypovolemic 3
Clinical Management
- Assessing a patient's volume status and fluid responsiveness is critical in maintaining the balance between meeting a patient's fluid needs and contributing to complications of volume overload 5
- The choice of resuscitation fluid may be important in the context of hypovolemia, with some evidence suggesting that certain colloids might be helpful in diminishing post-ischemic microvascular leukocyte adherence 2
- Fluid therapy in vomiting and diarrhea is essential to correct hypovolemia, dehydration, acid-base imbalance, and serum electrolyte abnormalities 6