we are heart hospital clinical engineers of Brazil, and our doubt refer Servo 900c expirated minute volume calibration. The Servo 900c operation manual (chapter 13 - Calibration) begins without specification of tube lengths, just suggest adult tubes.

My question is: Can I use a specific length tube or several lengths tubes for calibration?? What must I based for a permanent protocol?? I know that causes diference but i would like to know its limit.