History and physical can often make the diagnosis of hypovolemic shock. For patients with hemorrhagic shock, a history of trauma or recent surgery is present. For hypovolemic shock due to fluid losses, history and physical should attempt to identify possible GI, renal, skin, or third-spacing as a cause of extracellular fluid loss. Symptoms of hypovolemic shock can be related to volume depletion, electrolyte imbalances, or acid-base disorders that accompany hypovolemic shock.

Patients with volume depletion may complain of thirst, muscle cramps, and/or orthostatic hypotension. Severe hypovolemic shock can result in mesenteric and coronary ischemia that can cause abdominal or chest pain. Agitation, lethargy, or confusion may result from brain malperfusion. 

Although relatively nonsensitive and nonspecific, physical exam can be helpful in determining the presence of hypovolemic shock. Physical findings suggestive of volume depletion include dry mucous membranes, decreased skin turgor, and low jugular venous distention. Tachycardia and hypotension can be seen along with decreased urinary output. Patients in shock can appear cold, clammy, and cyanotic.[3]

Various laboratory values can be abnormal in hypovolemic shock. Patients can have increased BUN and serum creatinine as a result of prerenal kidney failure. Hypernatremia or hyponatremia can result, as can hyperkalemia or hypokalemia. Lactic acidosis can result from increased anaerobic metabolism. However, the effect of acid-base balance can be variable as patients with large GI losses can become alkalotic. In cases of hemorrhagic shock, hematocrit and hemoglobin can be severely decreased. However, with a reduction in plasma volume, hematocrit and hemoglobin can be increased due to hemoconcentration.

Low urinary sodium is commonly found in hypovolemic patients as the kidneys attempt to conserve sodium and water to expand the extracellular volume. However, sodium urine can be low in a euvolemic patient with heart failure, cirrhosis, or nephrotic syndrome. A fractional excretion of sodium under 1% is also suggestive of volume depletion. Elevated urine osmolality can also suggest hypovolemia. However, this number also can be elevated in the setting of impaired concentrating ability by the kidneys.

Central venous pressure (CVP) is often used to assess volume status. However, its usefulness in determining volume responsiveness has recently come into question. Ventilator settings, chest wall compliance, and right-sided heart failure can compromise CVPs accuracy as a measure of volume status. Measurements of pulse pressure variation via various commercial devices has also been postulated as a measure of volume responsiveness. However, pulse pressure variation as a measure of fluid responsiveness is only valid in patients without spontaneous breaths or arrhythmias. The accuracy of pulse pressure variation also can be compromised in right heart failure, decreased lung or chest wall compliance, and high respiratory rates.

Similar to examining pulse pressure variation, measuring respiratory variation in inferior vena cava diameter as a measure of volume responsiveness has only been validated in patients without spontaneous breaths or arrhythmias. Measuring the effect of passive leg raises on cardiac contractility by echo appears to be the most accurate measurement of volume responsiveness, although it is also subject to limitations. [3][[4]

For patients in hemorrhagic shock, early use of blood products over crystalloid resuscitation results in better outcomes. Balanced transfusion using 1:1:1 or 1:1:2 of plasma to platelets to packed red blood cells results in better hemostasis. Anti-fibrinolytic administration to patients with severe bleed within 3 hours of traumatic injury appears to decrease death from major bleed as shown in the CRASH-2 trial. Research on oxygen-carrying substitutes as an alternative to packed red blood cells is ongoing, although no blood substitutes have been approved for use in the United States.

For patients in hypovolemic shock due to fluid losses, the exact fluid deficit cannot be determined. Therefore, it is prudent to start with 2 liters of isotonic crystalloid solution infused rapidly as an attempt to quickly restore tissue perfusion. Fluid repletion can be monitored by measuring blood pressure, urine output, mental status, and peripheral edema. Multiple modalities exist for measuring fluid responsiveness such as ultrasound, central venous pressure monitoring, and pulse pressure fluctuation as described above. In general, for hypovolemic shock, vasopressors should not be used because they can worsen tissue perfusion.

Crystalloid fluid resuscitation is preferred over colloid solutions for severe volume depletion not due to bleeding. The type of crystalloid used to resuscitate the patient can be individualized based on the patients’ chemistries, estimated volume of resuscitation, acid/base status, and physician or institutional preferences. Isotonic saline is hyperchloremic relative to blood plasma, and resuscitation with large amounts can lead to a hyperchloremic metabolic acidosis. Several other isotonic fluids with lower chloride concentrations exist, such as lactated Ringer's solution or PlasmaLyte. These solutions are often referred to as buffered or balanced crystalloids. Some evidence suggests that patients who need large volume resuscitation may have a less renal injury with restrictive chloride strategies and use of balanced crystalloids. Crystalloid solutions are equally as effective and much less expensive than colloid. Commonly used colloid solutions include those containing albumin or hyperoncotic starch. Studies examining albumin solutions for resuscitation have not shown improved outcomes, while other studies have shown resuscitation with hyperoncotic starch leads to increased mortality and renal failure.[5][6][7][8][9]

• Femoral shaft fractures in emergency medicine

• Gastrointestinal bleeding

• Hemorrhagic shock in emergency medicine

• Iron toxicity

• Pelvic fracture in emergency medicine

• Pregnancy trauma

• Peptic ulcer disease

• Placental previa imaging

• Thoracic aneurysm

• In patients with hypovolemic shock due to extracellular fluid loss, the etiology of fluid loss must be identified and treated.
• Monitoring electrolytes and acid/base status in patients in hypovolemic shock is of utmost importance.
• Trauma is the leading cause of hemorrhagic shock.
• The hemorrhagic shock should be treated with balanced transfusion of packed red blood cells, plasma, and platelets.
• Determining whether patients will be responsive to volume resuscitation should not rely on a single modality such as ultrasound, pulse pressure wave variation, passive leg raises, or central venous pressure. The decision for fluid administration should be based on the entire clinical presentation, laboratory values, and the aforementioned modalities.
• For patients with hypovolemic shock due to fluid loss, the crystalloid solution is preferred over colloid.

The management of hypovolemic shock requires an interprofessional team including ICU nurses. For patients with hypovolemic shock due to fluid loss, the crystalloid solution is preferred over colloid.These patients need monitoring of their fluid input and output and should be in an ICU setting. The outcomes depend on the cause of shock, the patient age, comorbidities and presence of renal failure.