Disadvantages: When a head hood is utilized, the oxygen content of the inspired gas may vary with hood position, amount of leakage, and movement of the infant out from under the hood. Pressure areas have been noted, particularly around the neck, when the head box is too small for the infant. Noise levels may be excessive, particularly when liter flow is high. In addition, the caregiver’s ability to visualize the infant’s face and head may be poor, particularly when humidity levels are high and there is condensation. There is a theoretical risk of carbon dioxide buildup if flow is low the hood is well sealed, and there is a risk of creating positive pressure if the hood is well sealed and the gas flow is high. High levels of humidity and condensation increase the risk of infection, particularly when the hood is used for extended periods.