The stomach content volume appears to reach a minimum 2 hours after clear liquid infestion. No solids or cow's milk for 6 hours prior to surgery. III.Physiologic differences A. Cardiovascular. Children have a higher cardiac output and oxygen consumption per kilogram than adults. 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.