You are transferring a 24-year-old female patient from a regional facility to a big city hospital. the patient had overdosed on fentanyl and was intubated prior to your arrival. they hand you labs that read as follows: ph 7.23, paco2 95, pao2 96. you do not have a ventilator and are the only resource available to transfer the patient. you will have to bag them with a bvm for the entire 30 minute transfer. vitals in the back of your unit are: bp 112/64, spo2 97% on bvm 15lpm, etco2 of 98mmhg, pulse of 88, rr of 12. they were sedated with ketamine before you arrived and are compliant with your bvm ventilations. in order to correct the low ph of 7.23, what would you want the etco2 reading on your monitor to do that would let you know the ph is shifting up toward the 7.35-7.45 range we want?