Asthma, one of the most common forms of respiratory distress, can come in many forms. Fortunately, most of these forms share common symptoms that can easily be replicated on a mechanical test lung. By creating a severely restricted airway and pairing it with a slightly compliant lung, we can provide settings that simulate an acute asthma attack.

Important settings for this simulation include:

  • Functional Residual Capacity—between 860mL and 990mL per adult lung, (80mL to 200mL infant) should be used.
    • Please note that residual capacity is only considered functional if it is downstream (during inspiration) of the airway resistor.
  • Airway Resistance—a resistance of 50cmH2O/L/s should be used to simulate this condition in adults. 500cmH2O/L/s should be used to simulate this condition in infants.
  • Dynamic Compliance—a lung compliance of 40mL/cmH2O should be used to simulate an adult and 4mL/cmH2O should be used to simulate an infant. It is important that this value is “dynamic” so that the compliance of the simulated lung will decrease as breaths begin to stack.

During normal ventilation, the increased airway resistance will create the high proximal pressure seen in victims of an acute asthma attack and the above-average compliance of the simulated patient will cause breath stacking unless the breaths delivered are properly regulated.

A simulation similar to this can be applied in a number of ways. It can allow students to get hands-on experience with rare conditions, replicate case-specific failures in ventilators, identify pros and cons of different ventilation techniques and more. If there is a specific symptom or condition that you would like to replicate, please let us know by leaving a comment below. We’d love to put together a simulation for you.

To simulate additional pulmonary problems and scenarios visit our page, Settings for Simulating Pulmonary Physiologies.