The New England Journal of Medicine (NEJM) recently published the large-scale multinational study “Handling Oxygenation Targets in the Intensive Care Unit” (HOT-ICU). Under the direction of Aalborg University Hospital, the survival rate of critically ill patients with acute pulmonary function limitation (hypoxemia) was studied. One group with lower and one with higher target oxygen levels were compared. Contrary to the original assumption, the mortality rate after 90 days was comparable in both groups.
Critically ill patients with lung dysfunction are often treated with oxygen in intensive care units. Oxygen, one of the oldest and most widely used drugs, is often supplied by mechanical ventilation, and a certain oxygen partial pressure (oxygen target value) in the blood is aimed for. However, different strategies with either higher or lower oxygen partial pressure are used in intensive care units worldwide. In intensive care practice and in the scientific literature, the respective benefits or risks of corresponding strategies remained unclear.
Surprising results
The results of the HOT-ICU study show no difference in 90-day mortality when critically ill patients in the higher (n = 1447.90 mmHg arterial partial pressure) and lower (n = 1441.60 mmHg arterial partial pressure) target group are compared. Thus, a lower target oxygen value does not reduce mortality after 90 days. Similarly, no significant difference was found for the criteria “proportion of days without life-sustaining measures” and “proportion of days without hospitalization”.
Large-scale multinational study
The HOT-ICU pragmatic study was conducted by a scientific team led by Aalborg University Hospital at 35 intensive care centers in Denmark, Finland, the Netherlands, Norway, the United Kingdom, Iceland, and Switzerland (Basel and Bern University Hospitals). It included 2928 adult critically ill patients with an oxygen demand of at least 10 liters per minute or an inspired oxygen percentage of 50%. Allocation to the two treatment groups (90 mmHg or 60 mmHg arterial partial pressure of oxygen) was randomized. The primary endpoint of the study was mortality at 90 days. The number of days without (necessary) life-sustaining measures, the number of days without hospitalization, and the ratio of patients with shock, myocardial infarction, stroke, and gastrointestinal circulatory disorders were also documented.
Outlook
After intensive discussions on the strategy of target oxygen levels in critically ill patients in recent years and arguments for and against both approaches, the current study results seem to support a “conservative” oxygen administration with lower target oxygen levels in adult critically ill patients. Prof. Joerg C. Schefold, MD, Chief of the Department of Intensive Care Medicine at Inselspital, University Hospital Bern, and member of the scientific team explains: “The study results on this everyday intensive care question are important because they contribute to a better understanding of the effects of corresponding strategies. They show that the ‘conservative’ strategy is not associated with a lower mortality rate. We expect our data to influence international recommendations regarding target oxygen levels to aim for in adult critically ill patients requiring oxygen supplementation.”
Source: University Hospital Bern
Original publication:
DOI: 10.1056/NEJMoa2032510, Publication in NEJM “Lower or Higher Oxygenation Targets for Acute Hypoxemic Respiratory Failure.”
