Oxygen by direct delivery
Instead of a ventilator — a syringe
Anna Novikovskaya, Naked Science
In case of a lack of oxygen in the patient's blood, doctors have two options. The first is the connection to an artificial lung ventilation (ventilator). Such ventilation can occur with the help of a special mask (non-invasive ventilation) or the introduction of an intubation tube into the trachea, into which an air mixture is supplied under pressure. The main problems when using a ventilator are an increased risk of developing pneumonia and possible lung damage due to the pressure of the injected air.
The second method is extracorporeal membrane oxygenation (ECMO). In this case, the blood is taken from the bloodstream, purified and oxygenated in a special apparatus, after which it returns to the patient's body, while donor blood is required to replenish its volume in the apparatus. The main disadvantages of ECMO are the constant use of anticoagulants to prevent blood clotting inside the device, a possible allergic reaction to donated blood and the high cost of the procedure (expensive equipment and highly qualified personnel are needed).
Now doctors may have a third way to increase the concentration of oxygen in the blood — by directly injecting it into the bloodstream. To do this, a mixture was prepared consisting of gaseous oxygen and a liquid containing phospholipids — complex fats that are part of our cell membranes. The property of phospholipids is their ability to form bubbles, so that when the mixture was passed through a series of nozzles of decreasing diameter, microscopic balls surrounded by a shell of phospholipids and with an oxygen "filling" inside were eventually obtained.
Most importantly, the diameter of each bubble was smaller than the diameter of an erythrocyte, a red blood cell responsible for oxygen transport. The phospholipid shell prevented the bubbles from sticking together, forming large bubbles, and the small diameter prevented clogging of blood vessels (which happens, for example, with decompression sickness). Once in the blood, the oxygen enclosed in the fatty envelope will gradually diffuse into the surrounding plasma, saturating the tissues of the body.
Scientists conducted experiments with animals and donated human blood: in all cases, the use of new technology led to a significant increase in the concentration of oxygen in the blood. Nevertheless, the study is still at an early stage of testing the results, and it may take several years before the technology is introduced into hospitals.
For now, researchers are going to test the new method on large animals in order to collect additional data and improve efficiency.
The results of the study are published in PNAS (Vutha et al., A microfluidic device for real-time on-demand intravenous oxygen delivery).
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