There will be no intervention to the patients. Nebulizers will be used as per current policies and procedures. They will only be marked on the outside at the water level every 2 hours for the first 6 hours. Once ready to be discarded will be collected for laboratory testing Once in the laboratory, nebulizers will be weight on a precision scale without liquid, then they will be filled with normal saline to the first mark (6th hour) and re-weight. The nebulizers will be filled to next mark and re-weight until 200 mls. of total volume are achieved. Solution output will be calculated as the weight difference between the 2 hour periods.