User's Manual

NIBP
13-5
Patient Factors Affecting Readings
Excess patient movement, speech, or muscle contractions (as a result of severe
pain or shivering) can interfere with automated NIBP readings. Ensure that the
patient is quiet and not moving during NIBP readings just as you would during
manual readings. Avoid applying external pressure to the cuff during readings.
Institute measures to minimize shivering and alleviate pain.
Some arrhythmias may cause beat-to-beat pressure fluctuations that can make
obtaining NIBP readings more difficult. Increased variability of readings can result
from these pressure variations. If it becomes difficult to obtain readings in the
presence of arrhythmia, pressure should be temporarily verified using another
method. Pressure also varies cyclically with normal respiration. With deep
respirations, or in certain patients, this effect may be enhanced, increasing
reading variability.
For patients in shock, indirect methods of measuring pressure (auscultatory,
oscillometric, doppler) may not be reliable because of peripheral vascular
changes. These changes include peripheral vasoconstriction and diminished
peripheral circulation resulting from shunting of blood to central organs. In some
cases, peripheral pulses or Korotkoff sounds may be diminished or disappear in
spite of adequate blood pressure. In such cases, measuring a cuff pressure may
be impossible or give misleading results. Direct (invasive) blood pressure
measurements should be considered in patients with signs of shock or any patient
who rapidly becomes unstable for unknown reasons.