Jan 10, 2018
Critically hypoxic or bradypneic patients need aggressive and effective oxygenation - quickly. In most cases, a standard BVM ventilation or NRB at 15L/min is sufficient to improve oxygenation. However, in a small subset of patients, a standard, unmodified BVM or NRB isn’t enough.
Usually if a patient does not improve with supplemental oxygen alone, the most reasonable explanation is shunt. Physiologic shunt occurs when the lungs are perfused normally but oxygen delivery to the alveoli is inhibited. You should suspect shunt whenever the patients SpO2 remains low despite application of high flow O2. In these cases you need to fully understand the capabilities of your oxygen delivery devices.