Narrow Pulse Pressure
David Woodruff
and diastolic, is an early indication of shock. Look for hypovolemia
or decreased cardiac output.
Often the systolic pressure will start to fall as cardiac output
decreases. A patient who is hypovolemic, or a patient who has
decreased cardiac output from an MI, will exhibit a decrease in the
systolic pressure.
The body’s compensatory mechanism and response to decreased cardiac
output is to stimulate the sympathetic nervous system. This will
cause vasoconstriction and result in a rise in the diastolic pressure
causing a narrowed pulse pressure.
A narrow pulse pressure in shock is consistent with hypovolemic and
cardiogenic causes. Septic shock will cause a widened pulse
pressure. One way to differentiate shock in your patients is to look
at the pulse pressure. A narrow pulse pressure associated with
hypovolemia would be hypovolemic. A narrow pulse pressure associated
with volume overload would be cardiogenic. A wide pulse pressure
associated with hypovolemic would be septic.
Watch for those changes and watch for those trends in the patient’s
vital signs. You may see the patient’s blood pressure and you may see
that pulse pressure narrowing before you start to see any other
symptoms that your patient is developing shock.
Type Pulse Pressure Volume
Hypovolemic Narrow Low
Cardiogenic Narrow High
Septic Wide Low