They support this higher output with a higher baseline heart rate. Infants are heart rate dependent for their cardiac output. In other words, they have a fixed stroke volume, and must increase their heart rate to increase cardiac output. This can make resuscitation quite difficult. Normal vital signs for children include higher heart rates and lower blood pressures than adults.
Minute volume is increased, corresponding with the increased cardiac output.
This is supported by an increased respiratory rate. Tidal volume and dead space are equivalent to adults on a per kilogram basis. Children desaturate rapidly because of increased utilization of oxygen per kilogram , and because their FRC is decreased under anesthesia. FRC decreases under anesthesia because of small alveoli, and a very compliant chest wall. Both of these things lead to increased atelectasis.