The clinical use of albumin: the point of view of a specialist in intensive care.

Abstract

In the last decades, research on albumin and its administration to critically ill patients have increased considerably, both in clinical and experimental settings. The observations obtained in research ground have gradually led, on the one hand, to important results1 with a potential clinical impact on the treatment of different pathological conditions, and, on the other hand, to discussions and controversies2–4. It is, therefore, mandatory to ask ourselves whether it is really so important to “care” about albumin when dealing with clinical research in intensive care and, if so, why. A rapid glance at the bulk of data available on the topic may guide the answer to these questions. In fact, it is very interesting to discover that a search for publications on “albumin” in Medline, as updated on October 2008, yields 158,083 items, which is surprisingly greater than the number of publications on “haemoglobin” (120,250), a protein that is undoubtedly quite important in human physiology and pathophysiology! Moreover, it is worth noting that almost 40% of all the publications on albumin have been concentrated in the last 10 years, once again underlying, as mentioned above, how “hot” and current this topic may be considered. The beginning of the research on the applicability of albumin in clinical practice has generally been ascribed to World War II, with the first case series of seven very severely burned patients treated with intravenous administration of human albumin after they had been injured during the Pearl Harbour attack5. Actually, the first report of clinical use of human albumin in a patient with traumatic shock had been made few months before, as results from the archives of the Office of Medical History of the United States (http://history.amedd.army.mil/). The case reported concerned a 20-years old man admitted to the Walter Reed General Hospital in Washington D.C. “after he had sustained bilateral compound fractures of tibia and fibula and fractures of five ribs; and associated pleural damage, pneumothorax, and subcutaneous emphysema”. The patient appeared confused and had severe systemic hypotension. After he had received two units of human albumin (for a total amount of about 50 g) over a short period of time (about 30 min), his systemic arterial pressure recovered progressively, and 2 hours later, once his main fractures had also been stabilised, the patient appeared to be completely normotensive. The report described successful complete fluid resuscitation during the next day with a further amount of crystalloids. Of note, at no time after intravenous administration of human albumin was there any evidence of allergic reactions and/or circulatory failure, which had been the main obstacles during a previous research project on bovine-derived albumin. Thus, this first clinical case presented all the potentially important primary and secondary functions of albumin, such as its critical role in determining intravascular oncotic pressure and, on the other hand, its anti-inflammatory properties. From that first case on, many steps have been taken towards a precise clarification of all the characteristics of human albumin with a potential clinical impact in treating critically ill patients. In the present article, we will briefly review the clinical use of human albumin in intensive care medicine and present our point of view on this subject. To this purpose, we will first summarise the physiology and pathophysiology of albumin, we will then given an overview of the evidence currently available on its clinical use, and finally we will discuss the potential clinical indications for its administration, also reporting the design of a new clinical trial recently started in Italy.