Mean BP

The mean Blood Pressure BP as collected for the APACHE II score is calculated as follows:

Mean BP = round(((2x Diastolic) + Systolic)) ÷ 3)

Rounding may not be part of the original definition of Mean BP, but it is how we do it in order to get integers that work with the Apache Ranges.

Collection Instructions for mean arterial BP

• The data collector is responsible to collect from the chart, the worst BP (be it high or low) during the first 24 hours in ICU.
  • there is a BP Helper button to help pick the Sys/Dia combination for the worst mean BP
• The APACHE II score is based on the worst calculated mean BP.
• The mean BP is automatically calculated when the CSV data is uploaded to TMSX.
• when selecting the worst BP, you must also take into account #artificially changed BPs
• If BP is not available from the chart because of short stay or death, see Apache_II_General_Collection_Guidelines#Missing_Values_Rule_for_APACHE_II

artificially changed BPs

Look carefully when selecting this value. APACHE II score is based on the worst calculated mean BP (either high or low) which ever gives you the highest points as per scoring table, but you must also take in account the diagnosis. For example if a patient is in septic shock, you would want the lowest BP as opposed to the highest BP that is artificially enhanced by inotropes. We want the worst BP caused by condition, not intervention.