Product Manual
Directions for Use Troubleshooting 51
Event Causes and Corrective Actions
Note
Differences of up to 10 mmHg between manual and automatic readings are 
considered normal and occur for a number of reasons including intra-patient BP 
variability, observer hearing differences, and auscultatory deflation rate.
Table 16. Inaccurate Blood Pressure Readings
Possible Cause Corrective Action and Explanation
Incorrect cuff size Use Welch Allyn approved cuffs only.
Measure patient’s arm circumference midway between elbow and 
shoulder (see “Blood Pressure Cuff Selection” on page 35 to select correct 
cuff size). Use reference markings on cuff to ensure correct cuff size.
Patient’s arm position Ensure patient’s arm is at heart level.
Arm movement during blood pressure 
cycle
Keep arm still during blood pressure cycle.
• Movement may cause inaccuracies from artifact.
Blood pressure taken over clothing Take blood pressure on a bare arm.
Arrhythmia Check for regularity of heart rate (palpate pulse or check device).
• Moderate to severe heart rate irregularities may make blood pressure 
difficult to measure accurately.
Change in blood pressure between 
auscultatory reading and Spot LXi reading
Check blood pressure immediately before Spot LXi reading.
• Blood pressure is dynamic and changing. It is normal for blood 
pressure to fluctuate 5 to 10 mmHg.
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). Spot LXi 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 cuff no faster than 3 mmHg per second.
• One of the major sources of error in auscultatory blood pressure 
measurement is deflating the 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 result in inaccurate blood 
pressure measurements.
Poor auscultatory sound recognition by 
observer
Use high-quality stethoscope. Have a different observer check patient’s 
blood pressure.
Table 17. Cuff Inflation and Deflation with No Blood Pressure Reading Displayed (or Error Code in 
Display)
Possible Cause Corrective Action and Explanation
Leak in pneumatic system Ensure all cuff attachments are tight.
Carefully check for leaks in the blood pressure cuff, tubing, and pressure 
hose attached to Spot LXi.
Arm movement during cycle Keep arm still during blood pressure cycle. 
• Movement may cause inaccuracies from artifact, long cycle times, and 
error message.
Cuff tubing or pressure hose movement 
artifact
Do not contact cuff tubing or pressure hose during blood pressure cycle. 
• Movement may cause inaccuracies from artifact.










