Hypovolemic/Hemorrhagic Shock

Hypovolemic shock results from a decreased effective circulating volume of water, plasma, or whole blood and is the most common type of shock in adults and children. Rapid fluid loss leads to inadequate tissue perfusion and, if not reversed, ultimately, to organ failure. External, sudden blood loss resulting from penetrating trauma and severe gastrointestinal (GI) bleeding are common causes of hemorrhagic shock. A significant loss of greater than 30% of circulating volume results in a decrease in venous return, which in turn diminishes cardiac output, decreases perfusion to vital organs, and causes the symptoms associated with shock. When there is insufficient oxygen available to the cells, metabolism shifts from aerobic to anaerobic pathways. In this process, lactic acid accumulates in the tissues, and the patient develops metabolic acidosis. In addition, the tissues do not receive adequate glucose, and they cannot accomplish the removal of carbon dioxide. This disruption in normal tissue metabolism results initially in cellular destruction and, if left uncorrected, multiple organ failure and death. Significant hypovolemic shock (< 40% loss of circulating volume) lasting several hours or more is associated with a fatal outcome.

The American College of Surgeons separates hypovolemic/hemorrhagic shock into four classifications: Stage I occurs when up to 15% of the circulating volume, or approximately 750 mL of blood, is lost. These patients often exhibit few symptoms except perhaps anxiety and a slight increase in heart rate because compensatory mechanisms support bodily functions. Stage II occurs when 15% to 30%, or up to 1,500 mL of blood, of the circulating volume is lost. These patients have subtle signs of shock, but vital signs usually remain normal except for tachycardia and mild tachypnea. Patients may be slightly confused or irritable, and their skin may feel cool. Urine output will likely be reduced. Stage III occurs when 30% to 40% of the circulating volume, or from 1,500 to 2,000 mL of blood, is lost. This patient looks acutely ill, with significant tachycardia, thready pulses, hypotension, tachypnea, cold and clammy skin, lethargy, oliguria, and metabolic acidosis. The most severe form of hypovolemic/hemorrhagic shock is stage IV. The patient has severe tachycardia, weak or absent pulses, significant hypotension, hypothermia, acidosis, severe tachypnea, coma, cyanosis, and anuria. This patient has lost more than 40% of circulating volume, or least 2,000 mL of blood, and is at risk for exsanguination. Complications of hypovolemic shock include adult respiratory distress syndrome, sepsis, acute renal failure, disseminated intravascular coagulation, cerebrovascular accident, multiple organ dysfunction syndrome, and death.

Causes ⬆ ⬇

The loss of circulating volume can result from a number of conditions. Hemorrhage caused by active blood loss that results from trauma is a frequent source of hypovolemia. Both motor vehicle crashes (MVCs) and penetrating injuries from guns or knives can lead to hypovolemic shock. Active bleeding or rupture of internal organs, such as the bowel or the fallopian tube when caused by an ectopic pregnancy, can quickly result in hypovolemia even without obvious bleeding. Ruptured aortic aneurysm leads to hypovolemic shock due to rapid internal hemorrhage. Profound decreases in circulating fluid volume can be caused by the plasma shifts seen in burns and ascites. Other sources of hypovolemia include decreases in fluid intake (dehydration) and increases in fluid output (vomiting, diarrhea, excessive nasogastric drainage, draining wounds, and diaphoresis). Excessive diuresis from diuretic overuse, diabetic ketoacidosis, and diabetes insipidus can also cause hypovolemia. Pregnancy-related disorders that can lead to hypovolemic shock include ruptured ectopic pregnancy, placenta previa, and abruption of the placenta.

Genetic Considerations ⬆ ⬇

No clear genetic contributions to susceptibility have been defined.

Sex and Life Span Considerations ⬆ ⬇

Hypovolemic shock can occur at any age and in all people. The most common cause of hypovolemic shock in children and older adults is dehydration. In comparison, although trauma can occur at any age, in young adults the major cause of hypovolemic shock is hemorrhage from multiple trauma. Most blunt trauma is associated with MVCs, which are two to three times more common in males than in females in the 15- to 24-year-old age group. Penetrating injuries from gunshot wounds and stab wounds, which are on the increase in U.S. preteens, teens, and young adults, are also more common in males than females. Chronic illness can alter an individual's compensatory abilities in the setting of hypovolemia. Hypovolemic shock related to an ectopic pregnancy occurs in females of childbearing age, and GI bleeding disorders are common in adults.

Health Disparities and Sexual/Gender Minority Health ⬆ ⬇

Trauma leading to hypovolemic shock may occur after traffic crashes and penetrating injury. In recent years, Black persons have been killed in traffic crashes at a rate almost 25% higher than that for White persons (National Highway Traffic Safety Administration [NHTSA], 2021). Native American persons have the highest rate of MVC injury in the United States, more than twice the rate of Black persons (NHTSA, 2021). Experts have noted that Black and Native American communities tend to be crisscrossed by more dangerous roads than other communities. Non-Hispanic Black males have adjusted firearm death rates from two to seven times higher than males of other groups. Healthy People 2020 reports that non-Hispanic Black persons have the highest injury death rate in the United States (79.9 injury deaths per 100,000 people), followed by non-Hispanic White persons (79.2), Native American persons (78.2), Hispanic persons (45.5), and Asian/Pacific Islander persons (25.6). Recent work has shown evidence that rural populations have injury mortality rates that are more than twice as high as urban rates. Many factors contribute to these health disparities, including the risk of traffic injury in narrow rural roads, the lack of graded curves and lighted traffic signals on rural highways, and the distance from major trauma centers. Many of the most dangerous occupations, such as mining and agriculture, are found in rural areas and can result in injury, disability, and death. Sexual and gender minority persons have high risk for dating and interpersonal violence, violence related to bullying, and intentional and unintentional injury (Healthy People 2020). All of these situations may lead to hypovolemic shock.

Global Health Considerations ⬆ ⬇

The World Health Organization has identified MVCs as a growing epidemic in developing regions of the world. Both blunt and penetrating traumatic injury resulting in excessive bleeding can result from MVCs. In regions at war or with civil or political strife, traumatic injuries also lead to hemorrhagic shock. GI bleeding is a source of hypovolemic/hemorrhagic shock around the world.

Assessment ⬆ ⬇

ASSESSMENT

History

If the patient is actively bleeding or is severely compromised, the history, assessment, and early management merge together into the primary survey. The primary survey is a rapid (30- to 60-second) head-to-toe assessment that encompasses the emergency management of threats to airway, breathing, and circulation (ABCs) or life. If the patient's condition is stable enough to warrant a separate history, ask questions about allergies, current medications, preexisting medical conditions, and the factors that surround the hypovolemic/hemorrhagic condition.

Generally, patients who are experiencing hypovolemia because of trauma have either obvious bleeding or a history of injury to a vascularized area. Elicit information from the patient, emergency medical personnel, or the family as to how much blood was lost or how long the bleeding has continued. In the case of traumatic blood loss, it is important to remember that the most obvious injury site may not be the cause of the evolving hypovolemic shock.

Explore the possibility of a mechanism of injury, such as a burn or crush injury, leading to plasma fluid shifts extravascularly. Likewise, a history of either recent alterations in fluid volume intake or excessive loss—as in vomiting, diarrhea, excessive diaphoresis, or diuresis—is a potential indicator. In addition, obtain a subjective history of thirst, lethargy, and decreased urinary output.

Physical Examination

Early signs include restlessness, anxiety, agitation, confusion, weakness, lightheadedness, and tachycardia. The patient may appear either stable and alert or critically ill depending on the phase of hypovolemic shock. If the patient can maintain the ABCs, assess the patient's level of consciousness. Mental status changes may be indicators of diminished cerebral perfusion and are among the early signs of hypovolemic shock. Other early indicators include a decreased urinary output of less than 30 mL/hour, delayed capillary blanching, and signs of sympathetic nervous system stimulation (tachycardia, piloerection [gooseflesh]). Monitor vital signs, including heart and respiratory rate, blood pressure, and temperature. Changes in blood pressure (particularly hypotension) are a late rather than an early sign; pulse pressure, however, does initially widen and then narrow in the first two stages of shock. Orthostatic blood pressure changes also indicate hypovolemia. Inspect the patient's neck veins and palpate them for the quality of carotid pulse and neck vein appearance.

Four areas of the body where life-threatening hemorrhage may occur include the chest, abdomen, thighs (from a femoral fracture), and on the body's surface. Percuss the chest and lung fields for the presence of fluid. Auscultate the patient's bilateral breathing to check for decreased breath sounds and note the patient's respiratory effort. Auscultate the patient's heart and note any new murmurs or other adventitious heart sounds. Inspect the patient's abdomen for possible sites of fluid loss or compartmenting. When you auscultate the patient's abdomen, note the absence of bowel sounds, which may indicate a paralytic ileus, internal GI bleeding, or peritonitis. If bowel sounds are hypoactive, bleeding may be causing blood to shunt to other more vital organs. Check the abdomen for tenderness or enlargement. If the thighs have deformities or are enlarged, those may be signs of femoral fracture and bleeding into the thigh. Palpate the patient's peripheral pulses and note signs of decreased blood flow and inadequate tissue perfusion (cold, clammy skin; weak, rapid pulses; delayed capillary refill), but remember that these signs are late indicators of hypovolemic shock and may not be present until the patient reaches stage III. Check all parts of the body for external bleeding.

Psychosocial

If the patient has a decreased level of consciousness, attempt to identify a family member or significant other to discuss the patient's psychosocial history. Expect family members to be frightened, anxious, and in need of support. Of particular concern are the parents of young trauma patients who have to deal with a sudden, life-threatening event that may lead to the death of a child. Spouses of critically injured patients deal with role reversals, economic crises, and the fear of loss. Expect the family and partner of critically injured patients to express a range of emotions from fear and anxiety to grief and guilt.

Diagnostic Highlights

General Comments: No one specific diagnostic test identifies the degree of hypovolemic/hemorrhagic shock state. Several laboratory indicators provide valuable information on the status of the patient, however. These include arterial blood gases, hemodynamic parameters (cardiac output and cardiac index, oxygen delivery, oxygen consumption, central venous pressure, pulmonary capillary wedge pressure, and systemic vascular resistance), blood lactate level, electrolyte levels, hemoglobin, and hematocrit. The shock index (SI), which is the heart rate divided by the systolic blood pressure, is an indication of a patient's hypovolemic state. If the SI is less than 0.6, there is no shock. Mild shock is indicated by a value of 0.6 to less than 1.0. Moderate shock is from 1.0 to less than 1.4. Severe shock is a value of 1.4 or more. Radiographic, ultrasound, and imaging studies are important depending on the location of interest and might include chest and abdominal x-rays, transesophageal echocardiography, aortography, computed tomography, magnetic resonance imaging, or focused abdominal sonography for trauma. A pregnancy test should be completed for females of childbearing years, and if positive, followed by pelvic sonography.

Primary Nursing Diagnosis ⬆ ⬇

Diagnosis

DiagnosisRisk for bleeding as evidenced by hypotension, tachycardia, restlessness, frank hemorrhage, occult hemorrhage, and/or dyspnea

Outcomes

OutcomesBlood loss severity; Fluid balance; Circulation status; Shock severity: Hypovolemic; Hydration; Vital signs

Interventions

InterventionsBleeding reduction; Fluid resuscitation; Fluid monitoring; Blood product administration; IV therapy; Shock prevention; Shock management: Volume

Planning and Implementation ⬆ ⬇

PLANNING AND IMPLEMENTATION

Collaborative

The initial care of the patient with hypovolemic shock follows the ABCs of resuscitation. Measures to ensure adequate oxygenation and tissue perfusion include establishing an effective airway and a supplemental oxygen source, controlling the source of blood loss, and replacing intravascular volume. The American College of Surgeons recommends crystalloid fluids such as normal saline solution or lactated Ringer solution for stages I and II and crystalloids plus blood products for stages III and IV. Although vasopressors, such as norepinephrine or dopamine, do increase blood pressure in the setting of hypovolemic shock, they should never be started if there is insufficient intravascular fluid or if tissues remain underperfused despite an adequate blood pressure.

The objective of fluid replacement is to provide for adequate cardiac output to perfuse the tissues. Generally, any fluid transiently improves perfusion, but only red blood cells (RBCs) can carry enough oxygen to maintain cellular function. Three milliliters of crystalloid solutions should be infused for every 1 mL of blood loss. It is currently recommended to use caution in replacing fluids after trauma because the low flow state may protect the patient from further bleeding until the traumatic injury is repaired. After repair, fluid resuscitation can be used aggressively. RBCs or whole blood should be considered when fluid resuscitation with crystalloids is not successful. RBCs are preferred because they contain an increased percentage of hemoglobin per volume. Type-specific blood is preferred, although O-negative blood can be used if type-specific blood is not immediately available.

Pharmacologic Highlights

Medication or Drug Class	Dosage	Description	Rationale
Somatostatin (Zecnil)	250 mcg IV bolus, followed by a 250–500 mcg/hr continuous infusion; maintain for 2–5 days	Naturally occurring peptide from hypothalamus, GI tract, and pancreas	Increases reabsorption of water from the kidney tubules

Other Drugs: Octreotide (Sandostatin)

Independent

After initial stabilization of airway and breathing, the most important nursing intervention is to ensure timely fluid replacement. Fluid resuscitation is most efficient through a short, large-bore peripheral IV catheter in a large peripheral vein. The IV line should have a short length of tubing from the bag or bottle to the IV site. If pressure is applied to the bag, fluid resuscitation occurs more rapidly. If fluids can be warmed before infusion, the patient has a lower risk of hypothermia.

Positioning the patient can also increase perfusion throughout the body; place the patient in a modified Trendelenburg position to facilitate venous return and to prevent excessive abdominal viscera shift and restriction of the diaphragm that occurs with the head-down position. Fluid balance is of high importance; ongoing monitoring of intake and output is essential for care and decision making. Patients with hypovolemic shock require critical surveillance and monitoring at all times with serial vital signs.

Patients and their families are often frightened and anxious. If the patient is awake, provide a running explanation of the procedures to provide reassurance. Touch the patient's hand or arm to offer reassurance when possible. Explain the treatment alternatives to the family and keep them updated as to the patient's response to therapy. If blood component therapy is essential, answer the patient's and family's questions about the risks involved.

Evidence-Based Practice and Health Policy

Ozakin, E., Yazlamaz, N., Kaya, F., Karakilic, E., & Bilgin, M. (2020). Perfusion index measurement in predicting hypovolemic shock in trauma patients. Journal of Emergency Medicine, 59, 238–245.

The aim of this study was to investigate the relationship between perfusion index (PI) and blood transfusion necessity in multitrauma patients (N = 338). PI is derived from a pulse oximeter and shows the ratio of the pulsatile blood flow to the nonpulsatile blood flow (static blood) in peripheral tissue, and is an indirect and noninvasive measure of peripheral perfusion. They also investigated the risk of hemorrhage and recorded laboratory and clinical parameters.
The PI was less than 1 in 39 (11.5%) patients. They found positive correlations between PI and hemoglobin, hematocrit, base deficit, systolic blood pressure, SpO₂, and negative correlations with lactate, respiratory rate, and shock index. Thirty-one patients with PI less than 1 had blood transfusion within 24 hours. The main risk factors to predict blood transfusions were PI, pulse rate, and SpO₂. PI was more significant than lactate, base deficit, revised trauma score, and shock index measurements.

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DRG Information ⬇

Introduction ⬆ ⬇