Heartsaver First Aid Part I Progress Indicator: Question 3 of 22 3.  The BG-4 constant dosage must be _________________. Choices: 1.4 to 1.7 L/min. 1.5 to 1.9 L/min. 1.5 to 2.0 L/min. 1.7 to 1.9 L/min