Inclusion Criteria:  18 years or older admitted to UC San Diego La Jolla or Hillcrest Campus Intensive Care Units Patient requiring supplemental oxygen (including but no limited to nasal cannula, high flow devices, noninvasive positive pressure ventilation or mechanical ventilation  Exclusion Criteria:  <18 years Chest wall, anatomical, physical abnormalities, skin integrity issues precluding placement of electrode belt in direct contact with skin Patient is too unstable to position the belt/electrodes or tolerate head of bed changes Confirmed or suspected intracranial bleed, stroke, edema Active implants (i.e. implantable electronic devices such as pacemakers, cardioverter defibrillators, neurostimulators) or if device compatibility is in doubt Pregnant or lactating patients as safety and efficacy for use of EIT in such cases has not been verified