Hypovolemic Shock Clinical Presentation

• In a patient with possible shock secondary to hypovolemia, the history is vital in determining the possible causes and in directing the workup. Hypovolemic shock secondary to external blood loss typically is obvious and easily diagnosed. Internal bleeding may not be as obvious as patients may complain only of weakness, lethargy, or a change in mental status.
• Symptoms of shock, such as weakness, lightheadedness, and confusion, should be assessed in all patients.
• In the patient with trauma, determine the mechanism of injury and any information that may heighten suspicion of certain injuries (eg, steering wheel damage or extensive passenger compartment intrusion in a motor vehicle accident).
• If conscious, the patient may be able to indicate the location of pain.
• Vital signs, prior to arrival in the ED, should also be noted.
• Chest, abdominal, or back pain may indicate a vascular disorder.
• The classic sign of a thoracic aneurysm is a tearing pain radiating to the back. Abdominal aortic aneurysms usually result in abdominal, back pain, or flank pain.
• In patients with GI bleeding, inquiry about hematemesis, melena, alcohol drinking history, excessive nonsteroidal anti-inflammatory drug use, and coagulopathies (iatrogenic or otherwise) is very important.

  • The chronology of vomiting and hematemesis should be determined.
  • The patient who presents with hematemesis after multiple episodes of forceful vomiting is more likely to have Boerhaave syndrome or a Mallory-Weiss tear, whereas a patient with a history of hematemesis from the start is more likely to have peptic ulcer disease or esophageal varices.
• If a gynecologic cause is being considered, gather information about the following: last menstrual period, risk factors for ectopic pregnancy, vaginal bleeding (including amount and duration), vaginal passage of products of conception, and pain. All women of childbearing age should undergo a pregnancy test, regardless of whether they believe that they are pregnant. A negative pregnancy test typically excludes ectopic pregnancy as a diagnosis.

The physical examination should always begin with an assessment of the airway, breathing, and circulation. Once these have been evaluated and stabilized, the circulatory system should be evaluated for signs and symptoms of shock.

Do not rely on systolic BP as the main indicator of shock; this practice results in delayed diagnosis. Compensatory mechanisms prevent a significant decrease in systolic BP until the patient has lost 30% of the blood volume. More attention should be paid to the pulse, respiratory rate, and skin perfusion. Also, patients taking beta-blockers may not present with tachycardia, regardless of the degree of shock.

Classes of hemorrhage have been defined, based on the percentage of blood volume loss. However, the distinction between these classes in the hypovolemic patient often is less apparent. Treatment should be aggressive and directed more by response to therapy than by initial classification.

• Class I hemorrhage (loss of 0-15%)

  • In the absence of complications, only minimal tachycardia is seen.
  • Usually, no changes in BP, pulse pressure, or respiratory rate occur.
  • A delay in capillary refill of longer than 3 seconds corresponds to a volume loss of approximately 10%.
• Class II hemorrhage (loss of 15-30%)

  • Clinical symptoms include tachycardia (rate >100 beats per minute), tachypnea, decrease in pulse pressure, cool clammy skin, delayed capillary refill, and slight anxiety.
  • The decrease in pulse pressure is a result of increased catecholamine levels, which causes an increase in peripheral vascular resistance and a subsequent increase in the diastolic BP.
• Class III hemorrhage (loss of 30-40%)

  • By this point, patients usually have marked tachypnea and tachycardia, decreased systolic BP, oliguria, and significant changes in mental status, such as confusion or agitation.
  • In patients without other injuries or fluid losses, 30-40% is the smallest amount of blood loss that consistently causes a decrease in systolic BP.
  • Most of these patients require blood transfusions, but the decision to administer blood should be based on the initial response to fluids.
• Class IV hemorrhage (loss of >40%)

  • Symptoms include the following: marked tachycardia, decreased systolic BP, narrowed pulse pressure (or immeasurable diastolic pressure), markedly decreased (or no) urinary output, depressed mental status (or loss of consciousness), and cold and pale skin.
  • This amount of hemorrhage is immediately life threatening.
• In the patient with trauma, hemorrhage usually is the presumed cause of shock. However, it must be distinguished from other causes of shock. These include cardiac tamponade (muffled heart tones, distended neck veins), tension pneumothorax (deviated trachea, unilaterally decreased breath sounds), and spinal cord injury (warm skin, lack of expected tachycardia, neurological deficits).
• The 4 areas in which life-threatening hemorrhage can occur are as follows: chest, abdomen, thighs, and outside the body.

  • The chest should be auscultated for decreased breath sounds, because life-threatening hemorrhage can occur from myocardial, vessel, or lung laceration.
  • The abdomen should be examined for tenderness or distension, which may indicate intraabdominal injury.
  • The thighs should be checked for deformities or enlargement (signs of femoral fracture and bleeding into the thigh).
  • The patient's entire body should then be checked for other external bleeding.
• In the patient without trauma, the majority of the hemorrhage is in the abdomen. The abdomen should be examined for tenderness, distension, or bruits. Look for evidence of an aortic aneurysm, peptic ulcer disease, or liver congestion. Also check for other signs of bruising or bleeding.
• In the pregnant patient, perform a sterile speculum examination. However, with third-trimester bleeding, the examination should be performed as a "double set-up" in the operating room. Check for abdominal, uterine, or adnexal tenderness.

The causes of hemorrhagic shock are traumatic, vascular, GI, or pregnancy related.

• Traumatic causes can result from penetrating and blunt trauma. Common traumatic injuries that can result in hemorrhagic shock include the following: myocardial laceration and rupture, major vessel laceration, solid abdominal organ injury, pelvic and femoral fractures, and scalp lacerations.
• Vascular disorders that can result in significant blood loss include aneurysms, dissections, and arteriovenous malformations.
• GI disorders that can result in hemorrhagic shock include the following: bleeding esophageal varices, bleeding peptic ulcers, Mallory-Weiss tears, and aortointestinal fistulas.
• Pregnancy-related disorders include ruptured ectopic pregnancy, placenta previa, and abruption of the placenta. Hypovolemic shock secondary to an ectopic pregnancy is common. Hypovolemic shock secondary to an ectopic pregnancy in a patient with a negative urine pregnancy test is rare but has been reported.