New Blood-Pressure Related Measure Accurately Predicts Mortality Risk in ICU Patients

A team led by investigators at Massachusetts General Hospital (MGH, Boston, MA, USA), in collaboration with researchers at Massachusetts Institute of Technology (MIT, Cambridge, MA, USA) has created a technique to measure a property of the circulation called the critical closing pressure. This is the blood pressure point at which tiny blood vessels collapse and blood circulation halts. Assessing the critical closing pressure can provide insights into blood vessel tone in response to disease and therapy. However, regularly measuring this in a clinical setting had remained a challenge until now.

To develop this innovative method, the team analyzed high-resolution waveform data from 5,532 blood pressure patients in MGH's cardiac intensive care unit. They developed an analysis using various measured parameters, such as arterial pressure, pulse pressure, and heart rate, to determine the critical closing pressure. Subsequently, the researchers introduced a metric known as 'tissue perfusion pressure', which is the difference between the average arterial blood pressure and the critical closing pressure. This measure was found to predict a patient's mortality risk, the duration of hospitalization, and the peak blood lactate level, which is an indicator of tissue oxygenation levels. Further research will focus on how different treatments affect tissue perfusion pressure. The researchers also plan to conduct clinical trials to verify if this innovative technique can help guide clinical treatments and improve health outcomes in critically ill patients.

“When treating patients with circulatory shock, it is essential to maintain adequate blood pressure targets, yet standard goals are not personalized to individual patients,” said senior author Aaron Aguirre, MD, PhD, an attending cardiologist and critical care specialist at MGH and an assistant professor of Medicine at Harvard Medical School. “We have developed a new metric that can identify individuals with inadequate tissue perfusion who are at risk for adverse outcomes. We believe this method can be used to optimize treatment decisions for patients in the intensive care unit.”

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