Automation of ventilator control for hyperbaric oxygen therapy

摘要

The following study proposes the use of an automatically controlled ventilator during hyperbaric oxygen therapy (HBO therapy). HBO therapy has been used clinically since the mid 1800s and is currently approved by the Undersea and Hyperbaric Medical Society (UHMS) to treat 13 different medical conditions. The theory behind this therapy is that if a patient breathes 100% oxygen at pressures greater than 1 atmosphere, the oxygen will saturate the hemoglobin and will also dissolve into the blood plasma, drastically increasing the oxygen-carrying capacity of the blood and, subsequently, the body's ability to oxygenate tissue. The UHMS HBO therapy indications include, but are not limited to, carbon monoxide poisoning, refractory osteomyelitis, problem wound therapy, and necrotizing soft tissue infections. In most situations, the patient undergoing HBO therapy is conscious and breathing on his own, but there are instances where this is not the case. In these events, it is necessary for the patient to have a ventilator breath for him. Ventilation while undergoing HBO therapy can cause various complications due to the pressure changes inside the hyperbaric chamber. As chamber pressure changes, tidal volume fluctuates, requiring a respiratory therapist to constantly make manual changes to ventilator parameters. If the proper gas volume is not maintained, it could result in inadequate patient ventilation or excessive ventilation resulting in lung damage. The current study tests the use of a PIC microcontroller for automating ventilator control during HBO therapy. This will allow respiratory therapists to perform their regular functions without the added task of compensating for pressure variations.