PRAVEEN KATHIRVASAN
Intensive care units (ICU) have been critical for treating those severely ill with COVID-19. This branch of medicine deals with the process of temporarily supporting and replacing the function of multiple organ systems during serious illness and trauma. The first intensive care unit in Europe was set up by Bjørn Ibsen, an anaesthetist whose experimental form of positive pressure ventilation was pivotal in the intervention of the 1952 poliomyelitis epidemic in Copenhagen. Today, intensive care is considered a stand-alone speciality with the establishment of the Faculty of Intensive Care Medicine in 2010.
In 1952, the iron lung was the primary form of treatment for those suffering from paralysis of the muscles required for breathing and swallowing. Patients would lie in a cylindrical chamber with their head outside through a rubber sealed hole. As the pressure inside the chamber is lowered, the air pressure inside the patient’s chest cavity would become lower than the pressure outside the chamber forcing air into the patient’s lungs. This form of negative pressure ventilation is effective at removing the accumulation of carbon dioxide in severely ill patients. However, at Blegdam Hospital in Copenhagen, there were only seven respirators. Their cost and lack of availability made their sole use an unviable approach to the increasing prevalence of the disease.
Ibsen’s approach involved the use of positive pressure ventilation; air is directed into the lungs causing the thoracic cavity to expand and as the intercostal muscles relax, the volume inside the thorax decreases to allow for passive expiration. By performing a tracheostomy, a tube could be placed into the windpipe delivering oxygen to the lungs. Ibsen was permitted to attempt the procedure on a young child suffering from paralytic polio who was very likely to die without immediate intervention. By squeezing a bag attached to the rubber breathing tube at a fixed rate, oxygen would be pushed into the lungs. Releasing the bag would expel carbon dioxide through an escape valve on the breathing tube. At the time, making an incision into a patient’s neck was not often free of complication. Despite using a local anaesthetic, the patient fought against the manual ventilations. Injecting an anaesthetic agent (sodium thiopental), the patient became unconscious and Ibsen could now assist with their breathing. The patient survived and Ibsen’s experimental form of positive pressure ventilation was rapidly adopted throughout the hospital. As a result, the mortality of polio in Denmark fell by approximately 40%.
Ibsen’s actions caused a major shift in the attitudes towards the collaboration of healthcare professionals from many disciplines in intensive care medicine. With most anaesthetists working as freelancers and their roles restricted to the operating theatre, there was a strict social hierarchy when it came to healthcare in Denmark at the time. Ibsen’s experience in using a tracheostomy to manually ventilate a child infected with tetanus who was suffering from respiratory paralysis having been administered curare (a paralysing agent used to treat the disease at the time) was recognised by medical staff at the hospital. With an increasing mortality rate in Denmark and senior physicians desperate for a solution, Ibsen was eventually consulted.
Septicaemia is a life-threatening reaction to an illness and a common cause for admission to intensive care units. There remains no universal treatment for sepsis. Due to its symptoms resembling many common conditions, the diagnosis of sepsis possesses a challenge. As a result, broad-spectrum antibiotics with a range of side effects are often administered as an initial form of treatment. Patients also have varying immune responses to the condition. This, for instance, makes the use of steroids like hydrocortisone only feasible for those with severe inflammation of healthy tissues. Recently, the use of mesenchymal stem cell therapy (MSC) has been more popular in research for an effective treatment for sepsis. MSCs are stem cells that have been isolated from tissues such as umbilical cord blood, lung, and bone marrow. Since these stem cells are obtained from the same individual, they offer a substantially low chance for immune rejection. MSCs can secrete paracrine signals which limit the inflammation of tissues. MSCs may also aid in the treatment of sepsis through its antimicrobial behaviour and the modulation of immune cells.
With increasing demand, intensive care units will serve a more significant role in the makeup of hospitals over the next few decades. Early identification of patients requiring intensive care and advances in the use of biomarkers to classify disease could provide quicker and more personalised treatment plans.
Bibliography
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Guillamat-Prats, R. and Artigas, A. (2019). Current Status of Stem Cell Therapy for Sepsis and Acute Respiratory Distress Syndrome. Innovations in Cell Research and Therapy. [online] Available at: https://www.intechopen.com/books/innovations-in-cell-research-and-therapy/current-status-of-stem-cell-therapy-for-sepsis-and-acute-respiratory-distress-syndrome [Accessed 27 Sep. 2020].
Marini, J.J., DeBacker, D., Gattinoni, L., Ince, C., Martin-Loeches, I., Singer, P., Singer, M., Westphal, M. and Vincent, J.-L. (2019). Thinking forward: promising but unproven ideas for future intensive care. Critical Care, 23(S1) [Accessed 27 Sep. 2020].
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