Pulmonary edema can be divided into the following stages:
| Stage | Description |
| Interstitial pulmonary edema | Edema (fluid accumulation) is located primarily in the connective tissue supporting framework of the lung and the interstitium (space between cells) |
| Alveolar pulmonary edema | Edema within the pulmonary alveoli (air sacs) |
| Foaming | |
| Asphyxia, respiratory exhaustion | Respiratory depression (impending asphyxia) |
