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Appendix 3.2 Instructions for preparing table for cuff selection rules

Select 3 or 4 cuffs to be used in the survey. The ideal selection would have one 'basic' cuff (10-14 cm) which would be used in most cases i.e. gives best results for average arm circumference in population. Other two or three cuffs should be smaller and bigger than this 'basic' cuff.
Number the cuffs as 1 = narrowest cuff, 2 = 2nd narrowest cuff, ...
Measure the width of the bladder of cuffs. Let them be CUFF₁, CUFF₂, ...
Calculate the optimal arm circumference (OAC_i) for each cuff as:

Calculate the mid-point of each pair of adjacent cuff sizes (MP_ij),

Use the mid-points as cut points for selection of different cuffs.

Cuff	1	2	3
Cuff width	cuff₁	cuff₂	cuff₃
Arm circumference	< MP₁₂	MP₁₂ < arm circumference (cm) < MP₂₃	> MP₂₃

Example:

Selected cuffs are:
- cuff₁ = 8 cm
- cuff₂= 12 cm
- cuff₃ = 16 cm
Optimal arm circumference for each cuff is:
- OAC₁ = 8 cm / 0.4 = 20 cm
- OAC₂ = 12 cm / 0.4 = 30 cm
- OAC₃ = 16 cm / 0.4 = 40 cm
Mid-points between two cuffs are:
- MP₁₂ = (30 cm + 20 cm) / 2 = 25 cm
- MP₂₃ = (40 cm + 30 cm) / 2 = 35 cm
The range of arm circumference for each cuff is:
- cuff₁:
  - lower_limit = no lower limit
  - upper limit = 25 cm
- cuff₂:
  - lower_limit = 25 cm
  - upper_limit = 35 cm
- cuff₃:
  - lower_limit = 35 cm
  - upper_limit = no upper limit

Note: Due to this algorithm, two cuffs will always overlap as one has same upper limit than other one has as lower limit. To avoid confusion in use, when preparing the final instruction table for cuff use this overlap should be corrected.

Cuff width	8 cm	12 cm	16cm
Arm circumference (cm)	< 25 cm	25 cm < arm circumference < 35 cm	> 35 cm

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