Total cycle time is calculated as?

Total cycle time is calculated as?

• A. Ti = TCT / (I + E)
• B. 60 / RR
• C. Te = TCT - Ti
• D. Flow x Ti

Answer: (B)

Total cycle time is the duration of one complete breath. At a given respiratory rate, there are RR breaths each minute, so the time for each breath is 60 seconds divided by RR. For example, at 20 breaths per minute, the total cycle time is 60/20 = 3 seconds per breath. This directly defines how long one full inhale–exhale cycle lasts. If you know the I:E ratio, you can split that cycle time into inspiratory and expiratory portions (Ti and Te) using Ti = TCT × [I / (I + E)] and Te = TCT × [E / (I + E)]. The other options either describe parts of the cycle or relate to flow or volumes, not the direct calculation of total cycle time from the rate.

Total cycle time is the duration of one complete breath. At a given respiratory rate, there are RR breaths each minute, so the time for each breath is 60 seconds divided by RR. For example, at 20 breaths per minute, the total cycle time is 60/20 = 3 seconds per breath. This directly defines how long one full inhale–exhale cycle lasts.

If you know the I:E ratio, you can split that cycle time into inspiratory and expiratory portions (Ti and Te) using Ti = TCT × [I / (I + E)] and Te = TCT × [E / (I + E)]. The other options either describe parts of the cycle or relate to flow or volumes, not the direct calculation of total cycle time from the rate.