Permissive Hypotension for Surgery

(PHACS Trial)

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Massachusetts General Hospital

Disqualifiers: Severe shock, Renal dysfunction, Cirrhosis, Stroke, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 1

Duration: 2 to 3 days

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores whether permissive hypotension can improve recovery after heart surgery. Permissive hypotension involves maintaining slightly lower blood pressure to see if it reduces the need for blood pressure medications and shortens ICU stays. Participants will either receive this new approach or continue with the standard care typically given during heart surgery. Those scheduled for elective heart surgery without severe heart issues or other major health problems might be suitable for this trial. As an unphased trial, it offers participants the chance to contribute to innovative research that could enhance heart surgery recovery methods.

Do I need to stop my current medications for the trial?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the trial coordinators or your doctor.

What prior data suggests that permissive hypotension is safe for surgery?

Research has shown that maintaining lower blood pressure during surgery, known as permissive hypotension, is generally safe for patients. Studies have found no difference in death rates when comparing this method to traditional blood pressure management in heart surgery. For instance, one study reported similar death rates in both groups, with about 4.3% of patients in each group. This indicates that permissive hypotension does not increase the risk of death compared to usual practices. Overall, evidence suggests that this approach is well-tolerated and does not lead to more deaths than usual care. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about permissive hypotension for surgery because it offers a new approach to managing blood pressure during cardiac procedures. Traditional care usually aims to maintain a higher mean arterial pressure (MAP) to ensure adequate blood flow. However, permissive hypotension allows for a lower MAP target of over 60mmHg, which might reduce the risk of complications associated with higher blood pressures. This approach could lead to improved surgical outcomes and safety, sparking interest in discovering how it might benefit patients compared to standard practices.

What evidence suggests that permissive hypotension might be an effective treatment for surgery?

This trial will compare permissive hypotension with standard care during surgery. Research has shown that allowing lower blood pressure during surgery, known as permissive hypotension, can reduce blood loss and improve the surgical process. Studies have found that this approach does not increase the risk of death in heart surgeries compared to traditional blood pressure management methods. In some cases, it has even led to better results, such as reducing the need for drugs to raise blood pressure and possibly shortening ICU stays. However, researchers are still investigating its effects on long-term outcomes. Overall, permissive hypotension appears to be a promising method for managing blood pressure during surgery. ^{1 2 3 5 6}

Are You a Good Fit for This Trial?

This trial is for patients who have low blood pressure following cardiac surgery. The study aims to include individuals who can safely participate in a comparison of permissive hypotension versus usual care post-surgery.

Inclusion Criteria

I am scheduled for a planned heart surgery.

Exclusion Criteria

Rapidly increasing pressors within 60 mins of arrival

Pre-specified MAP goal as determined by clinical team

I was admitted to the ICU in severe shock needing high doses of specific heart medications.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

1 day

1 visit (in-person)

Treatment

Participants are randomized to either permissive hypotension or usual care, with monitoring of hemodynamics and vasopressor use

2 to 3 days

Continuous monitoring in ICU

Follow-up

Participants are monitored for safety and effectiveness after treatment, including cognitive assessment and survival to hospital discharge

1 week

Daily assessments in hospital

What Are the Treatments Tested in This Trial?

Interventions

• Permissive Hypotension

Trial Overview

The trial is testing the approach of allowing lower than normal blood pressure (permissive hypotension) after heart surgery, compared to the standard treatment. It will look at how this affects the need for drugs that raise blood pressure, ICU stay duration, organ function, and overall patient outcomes.

How Is the Trial Designed?

Group I: Permissive hypotension Intervention Experimental Treatment 1 Intervention

In addition to the regular care provided to cardiac surgery patients, those in the permissive hypotension intervention arm will have a MAP target \> 60mmHg.

Group II: Standard of Care Active Control 1 Intervention

Patients randomized to the standard of care arm will receive the regular care provided to cardiac surgery patients.

Who Is Running the Clinical Trial?

Massachusetts General Hospital

Lead Sponsor

Trials

3,066

Recruited

13,430,000+

Published Research Related to This Trial

A new preoperative risk model called the HEART score was developed to predict intraoperative hypotension or bradycardia in patients undergoing elective noncardiac surgery, based on data from 193 patients.

The HEART score, which includes factors like preoperative heart rate, hypotension, age, medication use, and type of surgery, was found to be moderately predictive of these adverse events, helping to better stratify patient risk and guide perioperative management.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Predictors of intraoperative hypotension and bradycardia. Cheung, CC., Martyn, A., Campbell, N., et al.[2022]

Effective management of perioperative hypertension is crucial as it significantly reduces the risk of serious complications such as stroke, acute coronary syndrome, and renal dysfunction, which can lead to increased morbidity and mortality.

Continuing chronic antihypertensive medications during the perioperative period has been shown to improve patient outcomes, highlighting the importance of maintaining blood pressure control before, during, and after surgery.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Isolated perioperative hypertension: clinical implications & contemporary treatment strategies. Dodson, GM., Bentley, WE., Awad, A., et al.[2019]

Deliberate hypotension can effectively reduce blood loss during surgery and improve the surgical field, but it must be carefully managed to avoid risks of inadequate blood flow to vital organs, especially in patients with a history of hypertension.

For most patients, maintaining systolic arterial pressure above 80 torr is safe during induced hypotension, while careful monitoring of vital signs and blood gases is crucial to ensure patient safety and successful outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Deliberate hypotension. Ewards, MW., Flemming, DC.[2019]

An automated closed-loop vasopressor administration device successfully maintained mean arterial pressure (MAP) within 5 mmHg of the target 80 mmHg for 98% of the intraoperative period in a swine model of induced hypotension.

This study demonstrates that norepinephrine can be accurately titrated using this automated system, suggesting a potential for improved management of intraoperative hypotension and reduced risk of postoperative complications.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Automated Titration of Vasopressor Infusion Using a Closed-loop Controller: In Vivo Feasibility Study Using a Swine Model. Joosten, A., Delaporte, A., Alexander, B., et al.[2020]

Perioperative hypertension is common and requires careful management by anaesthetists to make informed decisions about antihypertensive therapy and surgical risk assessment.

Management strategies must consider the potential impacts of left ventricular diastolic dysfunction and reduced coronary reserve on patient outcomes during surgery.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Perioperative hypertension: new strategies for management. Skarvan, K.[2019]

Continuing antihypertensive therapy up to the date of surgery significantly reduces perioperative risks for patients with hypertension, highlighting the importance of managing blood pressure before and during surgical procedures.

Effective collaboration among internists, surgeons, and anesthesiologists is crucial for safely managing hypertensive patients during operations, ensuring careful selection of anesthetics and continuous patient monitoring.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Hypertension and surgical risk]. Hoffmann, D.[2007]

Deliberate reduction of blood pressure during surgery has been controversial for 30 years, with many studies lacking rigorous control standards.

The article reviews the impact of blood pressure reduction on organ perfusion and provides recommendations on the safe application and limitations of this technique based on the summarized results.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Deliberate hypotension in head and neck surgery. Ward, CF., Alfery, DD., Saidman, LJ., et al.[2019]

In a meta-analysis of 10 randomized trials involving 9359 patients, permissive management of intraoperative blood pressure (mean arterial pressure ≤60 mm Hg) did not increase mortality compared to targeted management (mean arterial pressure >60 mm Hg).

Permissive blood pressure management was associated with a lower incidence of atrial fibrillation and a shorter length of hospital stay, suggesting potential benefits beyond mortality rates.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intraoperative hypotension and postoperative outcomes: a meta-analysis of randomised trials. D'Amico, F., Fominskiy, EV., Turi, S., et al.[2023]

Perioperative hypertension is common and can lead to serious complications like infarctions and strokes if not treated, but aggressive treatment is generally not necessary as most cases are hypertensive urgencies rather than emergencies.

For managing hypotension during surgery, the recommended approach includes reducing anesthesia depth, administering intravenous fluids, and using vasopressors like ephedrine or phenylephrine when mean arterial pressure drops below 60 mm Hg.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Cardiovascular anesthetic complications and treatment in oral surgery. Adlesic, EC.[2013]

Tight blood pressure control during major non-cardiac surgery significantly increased the mean arterial pressure (MAP) above 85 mm Hg and reduced instances of hypotension compared to routine management, indicating a potential safety benefit.

Delaying the restart of chronic antihypertensive medications until the third postoperative day did not adversely affect postoperative systolic blood pressure, suggesting that this approach may be safe and feasible in the context of tight blood pressure management.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Tight perioperative blood pressure management to reduce complications: a randomised feasibility trial. Li, K., Hu, Z., Li, W., et al.[2023]

Intra-arterial blood pressure monitoring in 4342 patients undergoing noncardiac surgery was associated with a higher incidence of peri-operative myocardial injury (38.7%) compared to noninvasive monitoring (25.7%), indicating a potential increased risk of morbidity.

Even after adjusting for various patient and surgical factors, intra-arterial monitoring remained linked to a greater risk of myocardial injury, suggesting that this method may not improve outcomes and could warrant further investigation in future studies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Mode of blood pressure monitoring and morbidity after noncardiac surgery: A prospective multicentre observational cohort study. Abbott, TEF., Howell, S., Pearse, RM., et al.[2023]

Citations

1.

ncbi.nlm.nih.gov

ncbi.nlm.nih.gov/books/NBK558915/

Permissive Hypotension - StatPearls - NCBI Bookshelf - NIH

Permissive hypotension refers to a deliberate medical strategy, particularly in emergency and critical care settings, where blood pressure is allowed to remain ...

2.

sciencedirect.com

sciencedirect.com/science/article/pii/S0007091223004798

Intraoperative hypotension and postoperative outcomes

No difference in mortality between permissive and targeted blood pressure management groups was observed in cardiac surgery (19/441 [4.3%] vs 19/439 [4.3%], OR ...

3.

withpower.com

withpower.com/trial/phase-hypotension-3-2024-653bf

Permissive Hypotension for Surgery (PHACS Trial)

Permissive Hypotension Therapy is unique because it deliberately lowers blood pressure during surgery to reduce blood loss and improve surgical conditions, ...

4.

link.springer.com

link.springer.com/article/10.1007/s12630-025-02972-w

Blood pressure management in cardiac surgery: how low ...

Lastly, in 2022, a confirmatory study by De La Hoz et al. found that hypotension (MAP < 65 mm Hg) throughout cardiac surgery was associated with ...

5.

jintensivecare.biomedcentral.com

jintensivecare.biomedcentral.com/articles/10.1186/s40560-016-0202-z

Permissive hypotension/hypotensive resuscitation and ...

Several researchers have reported the effectiveness of permissive hypotension in clinical and experimental studies. In those studies, target ...

6.

bjanaesthesia.org.uk

bjanaesthesia.org.uk/article/S0007-0912(23)00691-8/fulltext

Intraoperative hypotension and postoperative outcomes. ...

The meta-analysis reported that there was no difference in mortality between permitting hypotension (ie mean arterial pressure [MAP] 45–59 mm Hg) and targeting ...