Service manual

Service Manual Troubleshooting 31
Incorrect reference Use the correct Korotkoff sound to determine diastolic blood pressure.
• Many listeners incorrectly equate diastolic blood pressure with the
disappearance of sound only (phase 5). The Welch Allyn Spot Vital Signs was
developed using the American Heart Association recommendations, which state
that phase 5 be used unless sound continues to 0 mmHg, in which case the
change in the quality of sound (phase 4) is to be used.
Deflate blood pressure cuff no faster than 3 mmHg per second.
• One of the major sources of error in auscultatory blood pressure measurement is
deflating the blood pressure cuff too quickly. The American Heart Association
recommends deflation no faster than 3 mmHg per second.
Only use a sphygmomanometer that is calibrated.
• An uncalibrated sphygmomanometer may take inaccurate blood pressure
measurements.
Change in blood pressure
between auscultatory reading
and Welch Allyn Spot Vital
Signs reading
Check blood pressure immediately prior to Welch Allyn Spot Vital Signs reading.
Poor auscultatory sound
recognition by observer
Use higher quality stethoscope. Have a different observer check patient’s blood
pressure.
Note: Differences of up to 10 mmHg are considered normal and occur for a number of reasons including intra-patient
blood pressure variability, observer hearing differences, and auscultatory deflation rate.
Table 9. Cuff Inflation and Deflation with No Blood Pressure Reading Displayed (or Error Code in
Display)
Possible Cause Explanation and Corrective Action
Leak in pneumatic system Ensure all blood pressure cuff attachments are tight. Carefully
check for leaks in the blood pressure cuff, tubing, and pressure
hose attached to the device.
Arm movement during cycle Keep arm still during blood pressure cycle. Movement may cause
inaccuracies from artifact.
Blood pressure cuff tubing or pressure hose
movement artifact
Do not contact blood pressure cuff tubing or pressure hose
during blood pressure cycle. Movement may cause inaccuracies
from artifact.
Table 10. No Blood Pressure Cuff Inflation
Possible Cause Explanation and Corrective Action
Connections between device and blood
pressure cuff loose
Check all connections (do not overtighten).
Table 11. Temperature Malfunction
Possible Cause Explanation Corrective Action
Error code displayed Broken probe Replace probe. Consult Service Manual. Notify biomedical
department or Welch Allyn Technical Support.
Low temperature
readings
Improper probe
placement
Place probe in most posterior sublingual pocket when in
Oral Mode. Verify patient has had nothing to eat or drink
for 20 minutes.
Table 8. Inaccurate Blood Pressure Readings
Possible Cause Explanation and Corrective Action