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CLOVERS: Crystalloid Liberal or Vasopressors Early Resuscitation in Sepsis

March 2018 to February 2022
NCT Identifier: 

Purpose: The CLOVERS study compares two methods of increasing blood pressure in patients with dangerously low blood pressure due to a suspected infection. One method is the first provide intravenous fluids to the patient, and then use drugs such as adrenalin (called vasopressors); the other method is to use the drugs first, and then use fluids.

Trial summary:

  • Study design: this is a multi-center, prospective, phase 3 randomized non-blinded interventional trial of fluid treatment strategies in the first 24 hours for patients with sepsis-induced hypotension (dangerously low blood pressure from a suspected infection).
  • Purpose: to determine the impact of a restrictive fluids strategy (vasopressors first followed by rescue fluids) as compared to a liberal fluid strategy (fluids first followed by rescue vasopressors) on 90-day in-hospital mortality in patients with sepsis-induced hypotension.
  • Sample size: this trial will enroll up to 2,230 subjects from PETAL network emergency rooms.

Update Feb 9, 2022:

NHLBI PETAL Network ends Phase 3 sepsis trial early

PETAL Network study found no significant difference in 90-day mortality rates, nor safety concerns, after providing patients with one of two common treatment strategies

Enrollment in a National Institutes of Health-supported trial with 1,566 patients being treated for sepsis at 51 U.S. medical centers ended early due to a lack of significant difference observed between two 24-hour treatment strategies.

NHLBI NEWS | Statement February 9, 2022, Time TBD

Contact: 301-496-5449

The Crystalloid Liberal or Vasopressors Early Resuscitation in Sepsis (CLOVERS) trial is a randomized clinical trial conducted by the Prevention and Early Treatment of Acute Lung Injury (PETAL) network and funded by the National Heart, Lung, and Blood Institute (NHLBI). In this Phase 3 study (NCT03434028), researchers randomly assigned patients being treated for sepsis with low blood pressure after initial treatment into one of two arms of the trial. The first arm preferentially used fluid infusions through an intravenous catheter to raise blood pressure before vasopressors (medications used to raise blood pressure). The second arm preferentially used vasopressors to raise blood pressure before additional intravenous fluids. Both approaches are currently used to support patients with sepsis. The goal of this study was to determine if the order of treatments would improve survival, measured over 90 days.

The CLOVERS trial started on March 7, 2018, and researchers planned to enroll up to 2,320 patients. After a scheduled interim analysis on Feb. 2, 2022, an independent data and safety monitoring board found that outcomes were similar in both arms and that further enrollment was unlikely to change the result. They also found no concerns regarding patient safety.

The researchers note that the findings are important since they show that both approaches to treating sepsis have similar outcomes. They will continue patient follow-up according to the protocol, including the completion of data collection on all patients already enrolled in the trial. Formal analyses of study data are underway and findings are forthcoming. Researchers plan to share findings from the trial through presentations at scientific meetings and by publishing results from the study in peer-reviewed journals.

Sepsis can produce immediate shock-like symptoms and affect multiple organs and systems following a bacterial or viral infection. Common symptoms include a sudden rise in heart rate or drop in blood pressure; chills, such as fever, shivering, or feeling very cold; confusion or disorientation; shortness of breath; extreme pain or discomfort; and clammy or sweaty skin. According to the Centers for Disease Control and Prevention, sepsis affects 1.7 million Americans and accounts for more than 250,000 U.S. deaths each year. Older adults, young infants, people with compromised immune function, and patients recently hospitalized are at greater risk for septic-like shock, the body’s extreme response to infection.

Through PETAL, NHLBI-supported researchers at 12 clinical centers and a coordinating center are studying ways to prevent and treat sudden lung injuries and acute respiratory distress syndrome that can occur following sepsis.

About the National Heart, Lung, and Blood Institute (NHLBI): NHLBI is the global leader in conducting and supporting research in heart, lung, and blood diseases and sleep disorders that advances scientific knowledge, improves public health, and saves lives. For more information, visit

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit