Free Airflow Through the Nettress Netting and Special Sheets Prevents CO2 Retention and Enables Uninhibited, Normal Infant Breathing Even When Breathing is Possible Only Through the Mattress Surface In a study performed at the Institute of Pulmonology, Hadassah University Hospital in Jerusalem, the mechanical properties of the Nettress were measured and defined with regard to aeration and ventilation. Three sets of experiments were conducted. Two were aimed to measure the aeration properties of the mattress and the third, to measure the resistive properties to airflow through the mattress. All tests were performed on two separate mattresses and each experiment was conducted on the bare, uncovered mattress as well as when covered with a fenestrated sheet (net sheet) and a regular commercially available cotton sheet (cotton sheet). The following sets of experiments were conducted:   1. Measuring the rate of CO2 elimination from a container with a known volume (head box) which is open on one side to the mattress- static diffusion. In this experiment, the head box (simulating the infants head upper airway) was placed with its open face on the mattress. This opening was blocked by a thin plastic sheet and an air mixture containing 4.8% CO2 was flushed into the head box. Once stable CO2 levels were achieved, the plastic sheet was removed and the gas mixture within the head box was allowed to statically diffuse through the mattress and equilibrate with the surrounding room air. CO2 concentrations were continuously measured until CO2 levels fell below 1%. 2. Measuring the rate of CO2 accumulation in the head box due to CO2 production by the quiet breathing of an average infant- dynamic diffusion. In this experiment, CO2 was introduced into the head box at a rate similar to the CO2 production of a normal infant. CO2 accumulation is determined by the difference between the ability of the mattress to facilitate airflow and the rate of incoming CO2. 3. 3. Measuring the resistance to air flow through the mattress. The aim of this experiment was to determine the level of pressure which is needed to overcome the resistive properties of the mattress. The greater the resistance of the mattress, the higher the pressure needed to be generated by an infant lying on it. This causes an increase in the work of infant breathing, tiring and finally accumulation of carbon dioxide. The following conclusions were drawn from these experiments: Nettress was found to have superior properties compared to known values of regularly used mattresses and bedding materials as published in the literature. The Nettress was found to have: A fast rate of CO2 elimination. The ability to clear away any CO2 accumulation, keeping the maximal attainable CO2 level below 1%. An insignificant resistance to air flow.