This study is being done to find out if the heat and moisture that build up during minimal flow anesthesia can lead to the growth of germs (microorganisms) inside the anesthesia equipment. Minimal flow anesthesia (using fresh gas flow of 0.5 liters per minute or less) is known to help protect the lungs and the environment. However, it may also cause water to collect in the equipment, which could allow germs to grow. In this study, we want to see whether this type of anesthesia is safe when it comes to the risk of germs in the equipment.