Ventilators: The Holy Grail of Mechanical Breathing

COVID was at its peak in 2020. ICUs were flooded with patients struggling to breathe, doctors in a race against the clock, chaos everywhere. Controlling this mayhem was a herculean task, however, it was made doable all thanks to an engineering marvel: Ventilators. Ventilators are life support machines powered by precise fluid dynamic mechanisms aiming to replicate the process of human respiration.

At first glance, breathing appears quite simple. Humans subconsciously inhale oxygen and exhale carbon dioxide about 22,000 times a day. However, the entire process is actually quite complicated. It begins with the diaphragm contracting, resulting in a pressure difference leading to air being drawn into the lungs. Tiny alveoli present in the lungs then exchange gases with the bloodstream, while the lungs constantly adapt and change according to activity, altitude and health. A ventilator must reenact this entire process artificially.

Most modern ventilators are heavily reliant on mechanical engineering principles such as fluid dynamics, control systems, and thermodynamics. The machine carefully regulates airflow, pressure, oxygen balance and frequency to properly simulate human breathing. However, too much pressure can damage lung tissue whereas too little pressure can deprive the body of oxygen. Therefore, feedback systems are implemented to monitor patient responses.

Human lungs are delicate structures, and every pair of lungs differs from one patient to another. For example, someone suffering from pneumonia, asthma, or acute respiratory distress syndrome (ARDS) may have lungs that are stiff and resistant to airflow. Ventilators use sensors and microcontrollers to measure pressure in the airway and then adjust airflow patterns as required. This is essentially a closed-loop control system( a concept commonly used in aerospace and automotive engineering) and this system helps not only with ventilators, but also various other machinery present in the medical world. Some emergency ventilators use compressed air systems with minimal moving parts, while others incorporate modular designs for faster assembly, though they require mobile parts and may not be as efficient as the first.

Mechanical ventilators are mainly used in hospitals and in transport systems such as ambulances and MEDEVAC air transport. In some cases, they can be used at home, if the illness is long term and the caregivers at home receive training and have adequate nursing and other resources in the home. However, it is pertinent to mention that being on a ventilator may make you more susceptible to pneumonia, damage to your vocal cords, or other risks or problems.

A technically perfect machine is useless if doctors cannot operate it quickly during emergencies. Modern ventilators thus prioritize intuitive interfaces, alarm systems, and fail-safe mechanisms. These allow doctors to operate these machineries with minimal training, preventing chaos in times of emergencies.

A lot of efforts are going towards improving ventilators for the betterment of the future of medicine. A team of researchers and engineers are aiming to create AI algorithms that can analyze, minute-by-minute, what’s happening to a patient and make recommendations to the ICU team. The ICU clinicians then apply their own expertise and knowledge of the patient’s history to make the adjustments needed to give the patient the best chance at recovery. The point is to adapt ventilators to individual needs, thereby ensuring the best possible ventilation, with the highest degree of safety.

Bibliography:

1. https://ufhealth.org/care-sheets/learning-about-ventilators
2. https://www.draeger.com/en_sea/Productfinder/Ventilators/Intensive-Care-Ventilators#information
3. https://www.nhlbi.nih.gov/health/ventilator
4. https://stmichaelsfoundation.com/our-stories/the-future-of-mechanical-ventilation