Final answer:
Chest rise during artificial ventilation indicates that air is reaching the lungs. This is due to the expansion of the thoracic cavity during inspiration, as the diaphragm and intercostal muscles work to draw air into the lungs, resulting in visible chest expansion.
Step-by-step explanation:
During artificial ventilation, the observation that indicates air is reaching the lungs and not the stomach is C) Chest Rise. When air is successfully ventilated into the lungs, the chest will visibly rise due to the expansion of the thoracic cavity. The process of inspiration involves the contraction of the diaphragm and external intercostal muscles which expands the thoracic cavity and decreases the pressure within the lungs, drawing air in. This expansion results in the observable rise of the chest. Conversely, gastric inflation or abdominal expansion can occur when air is incorrectly ventilated into the stomach, and pronounced shoulder movement is not an indicator of effective ventilation into the lungs.
In summary, pulmonary ventilation consists of inspiration and expiration. During inspiration, the increased volume of the thoracic cavity leads to chest rise, indicating that air is entering the lungs correctly. However, when the abdomen instead of the chest is seen to expand, air might be entering the stomach which is not the desired effect in artificial ventilation.