NEET SS Anesthesia: What the IMPROVE-multi Trial Means for Perioperative MAP Targets
A structured review of the IMPROVE-multi RCT (JAMA, December 2025) and its companion trials, built for NEET SS and INI SS anesthesia aspirants preparing for MD or DNB Anesthesia.
1. Why This Trial Matters for NEET SS Anesthesia Preparation
Intraoperative hypotension is one of those topics that comes back again and again in NEET SS, INI SS, and MD or DNB anesthesia vivas. IMPROVE-multi is the largest trial so far to test whether individualized MAP targets protect organs better than a fixed threshold after major abdominal surgery. This blog by Surgtest aims to address this.
Exam takeaway: if a viva question asks whether 65 mm Hg is still the right MAP floor for everyone, this is the trial to cite.
2. The Background Question
Current guidelines recommend keeping intraoperative MAP above 60 to 65 mm Hg during noncardiac surgery. This comes from observational data linking a sustained MAP below 65 mm Hg with acute kidney injury, myocardial injury, and death.
But a fixed threshold ignores individual variation. Roughly half of surgical patients have chronic hypertension, and baseline blood pressure varies widely between individuals. That raises an open question worth remembering for exams: do patients with a higher baseline BP need a higher intraoperative target to maintain organ perfusion?
Key baseline facts to remember
- Intraoperative MAP below 65 mm Hg for 10 minutes or more: AKI risk rises by around 60%, myocardial injury risk by around 30%, and mortality risk by around 4% (Wesselink et al., a 42-study systematic review).
- About 50% of elective major noncardiac surgery patients have chronic arterial hypertension at baseline.
3. IMPROVE-multi: Trial Design at a Glance
Parameter | Detail |
Design | Multicenter, randomized, single-blind superiority trial across 15 German university hospitals |
Population | Age 45 or older, elective major abdominal surgery, general anesthesia lasting 90 minutes or more, plus at least one high-risk criterion (n = 1134 in the primary analysis) |
Intervention arm | Individualized MAP target set to the patient’s own preoperative mean nighttime MAP, with a floor of 65 mm Hg and a ceiling of 110 mm Hg |
Control arm | Routine management with a MAP target of 65 mm Hg or higher |
Target-setting method | Overnight automated BP monitoring at 30-minute intervals, with nighttime readings from midnight to 6 AM averaged |
Intervention window | From induction of anesthesia to 2 hours after the end of surgery |
Primary outcome | A composite of AKI, acute myocardial injury, nonfatal cardiac arrest, or death within 7 postoperative days |
Secondary outcomes | 22 outcomes in total, including infectious complications at 7 days and a 90-day composite of KRT, MI, arrest, or death |
Why nighttime MAP?
Nighttime, or sleep, MAP is usually a patient’s lowest well-tolerated baseline. It’s a plausible surrogate for a safe intraoperative floor, though this remains unproven. It also sidesteps daytime confounders such as activity, anxiety, and the white-coat effect.
4. Results: The Key Numbers
Outcome | Individualized (n=567) | Routine (n=567) | RR (95% CI) | P value |
Primary composite (7 d) | 33.5% | 30.5% | 1.10 (0.93-1.30) | .31 |
Infectious complications (7 d) | 15.9% | 17.1% | 0.93 (0.71-1.21) | .63 |
90-day composite (KRT/MI/arrest/death) | 5.7% | 3.5% | 1.60 (0.93-2.77) | .12 |
30-day unplanned readmission | 9.4% | 9.3% | 1.02 (0.71-1.47) | >.99 |
None of the 22 secondary outcomes reached significance. A mixed-effects model adjusting for center gave a similarly null result (adjusted OR 1.16, 95% CI 0.90 to 1.49). Subgroups based on the degree of preoperative hypertension also showed no benefit.
- Patients on the individualized target ran a higher median MAP throughout surgery, with a smaller area under 65 mm Hg. In other words, the intervention worked physiologically.
- They received more norepinephrine (94.5% versus 87.3% of patients) to hit the higher targets.
- Fluid volumes were similar between groups, so the difference was vasopressor-driven rather than fluid-driven.
Exam takeaway: the protocol worked as designed and MAP did go up. It just didn’t reduce organ injury. This is a negative outcome trial, not a failed intervention, and that distinction is worth remembering.
What actually changed at the bedside
- Patients on the individualized target ran a higher median MAP throughout surgery, with a smaller area under 65 mm Hg. In other words, the intervention worked physiologically.
- They received more norepinephrine (94.5% versus 87.3% of patients) to hit the higher targets.
- Fluid volumes were similar between groups, so the difference was vasopressor-driven rather than fluid-driven.
Exam takeaway: the protocol worked as designed and MAP did go up. It just didn’t reduce organ injury. This is a negative outcome trial, not a failed intervention, and that distinction is worth remembering.
5. What This Trial Does and Doesn't Tell Us
- It does not mean hypotension is harmless. Profound, prolonged hypotension below 65 mm Hg was already rare in the control arm, so the trial couldn’t test whether going below that floor is dangerous.
- It does not validate any specific alternative threshold. It tested individualization as a strategy, not a specific number.
- It does show that chasing a higher, personalized MAP target, mostly through added vasopressor, didn’t reduce AKI, myocardial injury, or death in this population.
- A MAP target of 65 mm Hg or higher remains a reasonable default for most high-risk abdominal surgery patients.
6. The Bigger Picture: Three Trials, One Message
The same December 2025 JAMA issue carried a related trial asking a different question. PRETREAT tested risk-stratified, proactive MAP targets (70, 80, or 90 mm Hg based on predicted hypotension risk) against standard reactive management in noncardiac surgery.
Trial | Strategy tested | Primary outcome | Result |
IMPROVE-multi (n=1134) | Individualized MAP target (own nighttime MAP) | 7-day composite: AKI, myocardial injury, arrest, or death | No difference (RR 1.10, P=.31) |
PRETREAT (n=3247) | Risk-stratified proactive MAP targets (70/80/90) | 6-month functional disability (WHODAS 2.0) | No difference; stopped early for futility |
POISE-3 (n=7490) | Hypotension-avoidance (MAP ≥80) vs hypertension-avoidance (MAP ≥60) | Vascular death, myocardial injury, stroke, or arrest | No difference |
PRETREAT cut intraoperative hypotension by nearly half, and that still didn’t improve 6-month functional outcomes. The same pattern shows up in IMPROVE-multi: good BP control, no change in hard outcomes.
Exam takeaway: three large RCTs point to the same conclusion. Raising or individualizing the MAP target alone, without treating the underlying cause of hypotension, isn’t moving outcomes.
7. Limitations Worth Knowing
- Anesthesiologists were unblinded to group allocation, so care beyond documented parameters could have been influenced.
- About 95% of preoperative BP monitoring happened in-hospital rather than truly ambulatory, which may have imperfectly captured a patient’s normal baseline BP.
- No advanced hemodynamic monitoring, such as cardiac output measurement, was used to identify the underlying cause of hypotension (vasodilation, hypovolemia, myocardial depression, or bradycardia). Treatment was left to clinician discretion without a specific protocol.
- Nonfatal cardiac arrest and death were too rare in this trial to draw firm conclusions about these individual components.
- Continuation or discontinuation of antihypertensive medication on the morning of surgery wasn’t tracked, despite its potential influence on intraoperative hemodynamics.
8. Summary Box
- One-line conclusion: individualized MAP targets, based on preoperative nighttime MAP, did not reduce organ injury or death compared with routine MAP of 65 mm Hg or higher in high-risk major abdominal surgery.
- Contrast with INPRESS (2017): that 292-patient trial found a benefit from individualizing systolic BP within 10% of a single preoperative reading. IMPROVE-multi, larger and more rigorous, didn’t replicate it.
- Practical default for viva: maintain MAP at 65 mm Hg or higher per current POQI, ESAIC, and DGAI guidance. Individualizing targets upward isn’t supported by current level-1 evidence.
9. Frequently Asked Questions
What MAP target should I quote in a NEET SS or DNB anesthesia viva on intraoperative hypotension?
A MAP of 65 mm Hg or higher remains the safe default to quote, in line with current POQI, ESAIC, and DGAI guidance. IMPROVE-multi tested whether individualizing this target higher improves outcomes and found no benefit, so 65 mm Hg stays the practical answer for exams.
What is the IMPROVE-multi trial and why does it come up in NEET SS anesthesia preparation?
IMPROVE-multi is a 2025 JAMA-published RCT that tested individualized, patient-specific MAP targets against a fixed 65 mm Hg threshold in major abdominal surgery. It’s a recent, high-yield landmark trial that examiners like to build viva and MCQ questions around, since it directly challenges a widely assumed practice.
Is 65 mm Hg still the correct MAP floor to remember for exams?
Yes. Despite testing a more individualized, patient-specific alternative, IMPROVE-multi found no reduction in AKI, myocardial injury, or death with a higher personalized target. A floor of 65 mm Hg remains the evidence-backed default.
How is IMPROVE-multi different from PRETREAT and POISE-3?
All three are large 2025 to 2025-adjacent RCTs testing MAP management strategies during noncardiac surgery, and all three reached a similar null result. IMPROVE-multi tested individualized targets based on nighttime baseline MAP, PRETREAT tested risk-stratified proactive targets, and POISE-3 compared a higher hypotension-avoidance target against a lower hypertension-avoidance target. None showed a clear outcome benefit from raising or personalizing the MAP target alone.
Where can I practice more literature-based MCQs like this for NEET SS anesthesia?
Trials like IMPROVE-multi don’t just make good reading. They make good exam questions. The Surgtest Anesthesia Q-Bank builds MCQs directly off landmark and recent literature like this one: trial design traps, outcome-interpretation questions, and “which guideline changed and why” items that mirror how these papers actually get asked in NEET SS, INI SS, and DNB vivas and written papers.
- Literature-based MCQs drawn from current RCTs and major reviews, not just textbook recall.
- Explanations that walk through why an option is wrong, not just which one is right.
- Regularly updated as new trials, such as IMPROVE-multi, PRETREAT, and POISE-3, reshape practice.
- Built around NEET SS, INI SS, and DNB Anesthesia exam patterns.
If this breakdown was useful, the Surgtest Anesthesia Q-Bank has extensive literature-based questions ready for revision.
