An article published yesterday, April 13, 2020 in the Journal of High Altitude Medicine and Biology clarifies misconceptions in the media comparing high altitude pulmonary edema (HAPE)and COVID lung injury. The six authors include two critical care pulmonologists from the University of Washington: Andrew Luk MD and Eric Swenson MD, as well as Peter Hackett MD of the Hypoxia Institute in Telluride and the University of Colorado Altitude Research Center. Dr. Swenson is the editor of the journal and has given presentations in Summit County on altitude. Both Dr. Hackett and Dr. Swenson personally communicated with Dr. Chris yesterday.
Severe viral pneumonia, as seen in COVID-19, can cause Adult Respiratory Distress Syndrome (ARDS) leading to respiratory failure and the need for ventilator support. As with HAPE, this is a form of non-cardiogenic pulmonary edema, where the air sacs in the lung fill with fluid due to conditions not related to heart failure, the most common cause of pulmonary edema. Other causes include bacterial pneumonia, near-drowning, nervous system conditions, re-expansion, and negative pressure edema. Radiographic findings are similar in all these cases with diffuse bilateral densities in the lungs. All these patients have severe hypoxia.
At altitude, hypoxia can lead to uneven pulmonary vascular constriction, (hypoxic pulmonary vasoconstriction or HPV). In the areas with the highest pressure, fluid leaks from capillaries into the alveoli. With COVID, alveolar inflammation reduces the protein surfactant that maintains expansion of the alveoli. The alveolar collapse causes hypoxemia, low blood oxygen. Severe viral and bacterial infections also cause inflammation in other organs, such as the liver, kidneys, and brain, which is not seen with HAPE.
Medications used to treat HAPE are not likely to be useful in treating COVID pneumonia and may have harmful effects such as increasing perfusion to damaged areas of the lung that are not oxygenated.
Both these conditions likely have large numbers of patients with mild symptoms who recover without seeing a medical provider. However, both HAPE and COVID can cause a sudden, rapid deterioration with severe hypoxia and death.
ACCESS TO A PULSE OXIMETER TO TRACK OXYGEN SATURATION IS VITAL.
Oxygen levels below 90% merit medical attention. Pulse oximeters can be purchased online, at drug stores, or at Ebert Family Clinic.