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severe or prolonged diarrhea (cholera), prolonged vomiting, internal third space loss (as in peritonitis), or
crush injury. Tissue injury from trauma may worsen shock by causing microemboli that further activate the
inflammatory and coagulation systems. Hemorrhage sufficient to cause shock usually happens in the torso,
in the thigh(s) (femur fracture), or externally. Fractures of the femur, pelvis, and/or traumatic amputation are
associated with substantial blood loss. From a clinical perspective, attempts to quantify blood loss in order
to determine a shock category is of little value because even external blood loss is notoriously difficult to
quantify and quite often trauma patients have significant internal as well as external hemorrhage. Treat the
patient- not the evident blood loss.
Subjective: Symptoms
Constitutional: Diffuse weakness, anxiety/feelings of impending doom, difficulty concentrating, c/o being
chilled to the bone; progressive thirst; shortness of breath. Consider thirst progressing in severity and
breathing that becomes progressively deeper and more rapid to be evidence of worsening shock until proven
otherwise.
Objective: Signs
Using Basic Tools
Vital Signs: WARNING: Children and physically fit young adults may maintain near normal vital signs until
significant shock is present and death is imminent!
Pulse: Tachycardia except in some cases where an unexpected bradycardia is found (penetrating abdominal
trauma, ruptured ectopic pregnancy or other pelvic bleeding); B/P: Progressive hypotension and orthostatic
hypotension; narrowing pulse pressure (systolic - diastolic pressure); Respirations: Tachypnea/hyperpnea;
measurement of orthostatic vital signs may be helpful when significant postural hypotension is documented
but this test is neither sensitive nor specific for shock.
NOTES:
- Most useful of all the vital signs in assessing hypovolemic/hemorrhagic shock is the pulse pressure
(systolic - diastolic pressure), which becomes progressively narrowed as shock proceeds. The normal
pulse pressure for an adult is between 30 and 40 mm Hg. If a blood pressure cuff is not available,
estimate the pulse pressure by the strength of the pulse. A weakening pulse implies a narrowing pulse
pressure. - More important than the absolute value of any of the vital signs at a given point is their trend over time.
Do not overlook falling blood pressure, a narrowing pulse pressure, and a rising heart rate- these are
signs of progressing shock. - Continuously measuring the hourly urinary output is a readily obtainable, objective means of determining
the adequacy of intravascular fluids.
Inspection: Pale, diaphoretic, anxious appearing. If degree of shock/hypotension is severe (i.e., systolic
B/P < 60-70 mm Hg) then there may be evidence of altered mental status ranging from confusion to
unconsciousness. If shock is due to trauma there is often external evidence of traumatic injury.
Auscultation: Clear lungs with deep, rapid respirations unless there is intrathoracic trauma
Palpation: Cool, moist skin. In non-hypothermic patients an ascending palpation of the skin from feet to chest
to note the point at which the skin becomes warm is a useful, rapid, method for estimating the degree of
shock. The more severe the shock, the more proximal the level of warmth.
Mental status: Often described as being altered in moderate to severe shock but because cerebral blood flow
is preserved to the last, a patient’s mental status may be normal or near normal until right before death (when
MS is abnormal look for other causes, especially closed head injury in a traumatized patient)
Capillary refill: Normally prolonged beyond 3 seconds in shock BUT interpretation is difficult in elderly patients
(normal is up to 4.5 sec), cold environment or poor lighting.
Using Advanced Tools: Continuous monitoring of urinary output and pulse oximetry.
Assessment:
Differential Diagnosis
Vaso-vagal faint - transient hypotension due to bradycardia caused by parasympathetic stimulation
Hemorrhagic shock - intravascular volume depletion through blood loss. Body responses intact (narrow pulse
pressure).