Tight Perioperative Blood Pressure Management to Reduce Serious Cardiovascular, Renal, and Cognitive Complications.

  • End date
    Apr 25, 2025
  • participants needed
  • sponsor
    The Cleveland Clinic
Updated on 16 October 2022


The treatments will be: 1) norepinephrine or phenylephrine infusion to maintain intraoperative MAP ≥85 mmHg, delayed resumption of chronic antihypertensive medications, and a target ward systolic pressure ≥110 mmHg (tight pressure management); or, 2) routine intraoperative blood pressure management and prompt resumption of chronic antihypertensive medications (routine pressure management).


Consenting patients who take either angiotensin converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), or calcium channel blockers will be asked not to take the medications on the morning of surgery, and instead bring them with them to the hospital. Qualifying patients will be randomized 1:1, with random-sized blocks.

The treatments will be: 1) norepinephrine or phenylephrine infusion to maintain intraoperative MAP ≥85 mmHg, delayed resumption of chronic antihypertensive medications, and a target ward systolic pressure >110 mmHg (tight pressure management); or, 2) routine intraoperative blood pressure management and prompt resumption of chronic antihypertensive medications (routine pressure management).

Tight pressure management: In patients assigned to tight pressure management, angiotensin converting enzyme inhibitors and angiotensin receptor blockers will not be given the morning of surgery. Other chronic antihypertensives will only be given as necessary to treat hypertension.

A norepinephrine or phenylephrine infusion (in the preferred local concentration) will be prepared, connected to an intravenous catheter, and activated at a low rate. Norepinephrine can be safely given through a central catheter or peripherally.

General anesthesia will be induced with propofol or etomidate which will be given in repeated small boluses or target-controlled infusion in an effort to keep mean arterial pressure ≥85 mmHg. Clinicians will be encouraged to use etomidate when rapid-sequence inductions are required. Simultaneously, the vasopressor infusion will be adjusted with the same goal. Anesthetic dose, fluid administration, and vasopressor administration will be adjusted with the goal of maintaining the individual designated baseline mean arterial pressure. Invasive or non-invasive advanced hemodynamic monitoring is not required, but should be used when practical. Clinicians should use available information to optimize vascular volume, afterload, and inotropy.

Resumption of chronic anti-hypertensive medications will be delayed until the third postoperative day unless deemed necessary to treat hypertension or for some other clear indication because >90% of MINS occurs within 48 hours after surgery. When necessary to treat hypertension, chronic antihypertensive or new medications can be used per clinician preference. Clinicians will make what efforts they can to maintain postoperative systolic arterial pressures ≥110 mmHg during the initial three postoperative days by maintaining adequate hydration, using inotropic and chronotropic drugs, and vasopressor as necessary. This protocol specifies the blood pressure target but leaves implementation to clinical judgement.

Routine pressure management: In patients assigned to routine pressure management, ACEIs, ARBs, and/or calcium channel blockers can be given the morning of surgery if deemed appropriate by the attending anesthesiologist. The arterial catheter will be inserted before or after induction of anesthesia per clinician preference. General anesthesia will be induced and maintained per routine. Blood pressure will not be deliberately reduced, but per routine clinicians will presumably not intervene until MAP is <65 mmHg. As usual, chronic anti-hypertensive medications will be restarted shortly after surgery unless contraindicated by hypotension.

In both groups, other aspects of anesthetic management will be at the discretion of the responsible anesthesiologist, including the types and volumes of various fluids. Volatile or intravenous anesthesia is permitted.

There will be no limitation on ancillary vasoactive, chronotropic, and inotropic drugs. Clinicians will be free to use advanced hemodynamic monitoring (e.g., pulse-wave analysis, esophageal Doppler, etc.). Blood products will be given per routine. Similarly, postoperative analgesic management will be per routine and clinician preference. Neuraxial and peripheral nerve blocks are permitted, but epidural catheters should not be activated until surgery is nearly finished.

Because patients must be fairly sick to qualify for GUARDIAN, some will go to directly from surgery to critical care units, or much less often, become unstable and require transfer from a routine ward to an ICU. In either case, every effort will be to maintain randomized treatments and blood pressure targets.

In all cases, good judgement will predominate. Clinicians should always act in their patients' best interests, irrespective of the GUARDIAN protocol

Condition Blood Pressure
Treatment Vasopressor, Tight pressure management, Routine pressure management, Induction agent
Clinical Study IdentifierNCT04884802
SponsorThe Cleveland Clinic
Last Modified on16 October 2022


Yes No Not Sure

Inclusion Criteria

≥45 years old
Scheduled for major noncardiac surgery expected to last at least 2 hours
Having general endotracheal, neuraxial anesthesia, or the combination
Expected to require at least overnight hospitalization
Are designated ASA physical status 2-4 (ranging from mild systemic disease through severe systemic disease that is a constant threat to life)
Chronically taking at least one anti-hypertensive medication
Expected to have direct blood pressure monitoring with an arterial catheter
Cared for by clinicians willing to follow the GUARDIAN protocol
Subject to at least one of the following risk factors
History of peripheral arterial disease
History of coronary artery disease
History of stroke or transient ischemic attack
Serum creatinine >175 µmol/L (>2.0 mg/dl)
Diabetes requiring medication
Current smoking or 15 pack-year history of smoking tobacco
Scheduled for major vascular surgery
Body mass index ≥35 kg/m2
Preoperative high-sensitivity troponin T >14 ng/L or troponin I equivalent; defined as ≥15 ng/L (Abbott assay),73 19 ng/L (Siemens assay, [Borges, unpublished]), or 50% of the 99% percentile for other assays; B-type natriuretic protein (BNP) >80 ng/L or N-terminal B-type natriuretic protein (NT-ProBNP) >200 ng/L

Exclusion Criteria

Are scheduled for carotid artery surgery
Are scheduled for intracranial surgery
Are scheduled for partial or complete nephrectomy
Are scheduled for pheochromocytoma surgery
Are scheduled for liver or kidney transplantation
Require preoperative intravenous vasoactive medications
Have a condition that precludes routine or tight blood pressure management such as surgeon request for relative hypotension
Require beach-chair positioning
Have a documented history of dementia
Have language, vision, or hearing impairments that may compromise cognitive assessments
Have contraindications to norepinephrine or phenylephrine per clinician judgement
Have previously participated in the GUARDIAN trial
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