Intraoperative Mean Blood Pressure and Outcome

A sub-study of the POISE-3 randomized trial examined effects of a perioperative hypotension-avoidance strategy versus a hypertension-avoidance strategy on the risk of acute kidney injury

In this pre-specified sub-study of the POISE-3 trial, we examined the effect of a perioperative hypotension-avoidance strategy versus a hypertension-avoidance strategy on the risk of postoperative acute kidney injury (AKI). Altogether, 7307 patients were included from 110 hospitals in 22 countries. Patients were 45 years and older, had or were at risk of atherosclerotic disease, took at least one antihypertensive medication, and were scheduled for noncardiac surgery. Hypotension-avoidance strategy: (i) target intraoperative mean arterial pressure (MAP) 80 mm Hg or over, (ii) on day of surgery and for two days after, hold renin-angiotensin-aldosterone system inhibitors and use other antihypertensives in stepwise fashion if systolic blood pressure (SBP) 130 mm Hg or more. Hypertension-avoidance strategy: (i) target intraoperative MAP 60 mm Hg or more, (ii) continue all antihypertensives before and after surgery. Primary outcome: postoperative AKI, an increase in serum creatinine concentration of either 26.5 μmol/L or more (0.3 mg/dL or more) within 48 hours of randomization or 50% or more within seven days of randomization. The hypotension-avoidance group (3654 patients) used fewer antihypertensive medications than the hypertension-avoidance group (3653 patients); specifically, 6% vs. 38% used an ACEI or ARB on the day of surgery, and 6% vs. 47% and 7% vs. 50% one and two days after surgery, respectively. Patients also spent about half as much intraoperative time with a MAP under 80 mm Hg (27 vs. 60 minutes, respectively), but had little difference in average BP before or after surgery. There was no significant difference in AKI risk (15.1% vs. 14.4%). Results were consistent with other definitions of AKI and in patients with preexisting chronic kidney disease. Thus, a hypotension-avoidance strategy targeting a MAP greater than 80 mm Hg in the operating room and discontinued blood pressure medication during the perioperative period did not confer a lower risk of AKI compared to a hypertension avoidance strategy. Clinical trial registration number: NCT03505723.

Hypotension-Avoidance Versus Hypertension-Avoidance Strategies in Noncardiac Surgery : An International Randomized Controlled Trial

BACKGROUND

Among patients having noncardiac surgery, perioperative hemodynamic abnormalities are associated with vascular complications. Uncertainty remains about what intraoperative blood pressure to target and how to manage long-term antihypertensive medications perioperatively.

OBJECTIVE

To compare the effects of a hypotension-avoidance and a hypertension-avoidance strategy on major vascular complications after noncardiac surgery.

DESIGN

Partial factorial randomized trial of 2 perioperative blood pressure management strategies (reported here) and tranexamic acid versus placebo. (ClinicalTrials.gov: NCT03505723).

SETTING

110 hospitals in 22 countries.

PATIENTS

7490 patients having noncardiac surgery who were at risk for vascular complications and were receiving 1 or more long-term antihypertensive medications.

INTERVENTION

In the hypotension-avoidance strategy group, the intraoperative mean arterial pressure target was 80 mm Hg or greater; before and for 2 days after surgery, renin-angiotensin-aldosterone system inhibitors were withheld and the other long-term antihypertensive medications were administered only for systolic blood pressures 130 mm Hg or greater, following an algorithm. In the hypertension-avoidance strategy group, the intraoperative mean arterial pressure target was 60 mm Hg or greater; all antihypertensive medications were continued before and after surgery.

MEASUREMENTS

The primary outcome was a composite of vascular death and nonfatal myocardial injury after noncardiac surgery, stroke, and cardiac arrest at 30 days. Outcome adjudicators were masked to treatment assignment.

RESULTS

The primary outcome occurred in 520 of 3742 patients (13.9%) in the hypotension-avoidance group and in 524 of 3748 patients (14.0%) in the hypertension-avoidance group (hazard ratio, 0.99 [95% CI, 0.88 to 1.12]; P = 0.92). Results were consistent for patients who used 1 or more than 1 antihypertensive medication in the long term.

LIMITATION

Adherence to the assigned strategies was suboptimal; however, results were consistent across different adherence levels.

CONCLUSION

In patients having noncardiac surgery, our hypotension-avoidance and hypertension-avoidance strategies resulted in a similar incidence of major vascular complications.

PRIMARY FUNDING SOURCE

Canadian Institutes of Health Research, National Health and Medical Research Council (Australia), and Research Grant Council of Hong Kong.

Provisional Decision-Making for Perioperative Blood Pressure Management: A Narrative Review

Blood pressure (BP) is a basic determinant for organ blood flow supply. Insufficient blood supply will cause tissue hypoxia, provoke cellular oxidative stress, and to some extent lead to organ injury. Perioperative BP is labile and dynamic, and intraoperative hypotension is common. It is unclear whether there is a causal relationship between intraoperative hypotension and organ injury. However, hypotension surely compromises perfusion and causes harm to some extent. Because the harm threshold remains unknown, various guidelines for intraoperative BP management have been proposed. With the pending definitions from robust randomized trials, it is reasonable to consider observational analyses suggesting that mean arterial pressures below 65 mmHg sustained for more than 15 minutes are associated with myocardial and renal injury. Advances in machine learning and artificial intelligence may facilitate the management of hemodynamics globally, including fluid administration, rather than BP alone. The previous mounting studies concentrated on associations between BP targets and adverse complications, whereas few studies were concerned about how to treat and multiple factors for decision-making. Hence, in this narrative review, we discussed the way of BP measurement and current knowledge about baseline BP extracting for surgical patients, highlighted the decision-making process for BP management with a view to providing pragmatic guidance for BP treatment in the clinical settings, and evaluated the merits of an automated blood control system in predicting hypotension.

Safety of sedation for gastrointestinal endoscopy in a group of university-affiliated hospitals: a prospective cohort study

BACKGROUND

Service models for gastrointestinal endoscopy sedation must be safe, as endoscopy is the most common procedure performed under sedation in many countries. The aim of this prospective cohort study was to determine the patient risk profile, and incidence of and risk factors for significant unplanned events, in adult patients presenting for gastrointestinal endoscopy in a group of university-affiliated hospitals where most sedation is managed by anaesthetists.

METHODS

Patients aged ≥18 yr presenting for elective and emergency gastrointestinal endoscopy under anaesthetist-managed sedation at nine hospitals affiliated with the University of Melbourne, Australia, were included. Outcomes included significant airway obstruction, hypoxia, hypotension and bradycardia; unplanned tracheal intubation; abandoned procedure; advanced life support; prolonged post-procedure stay; unplanned over-night admission and 30-day mortality.

RESULTS

2,132 patients were included. Fifty percent of patients were aged >60 yr, 50% had a BMI >27 kg m ^-2, 42% were ASA physical status III-V and 17% were emergency patients. The incidence of significant unplanned events was 23.0% (including significant hypotension 11.8%). Significant unplanned intraoperative events were associated with increasing age, BMI <18.5 kg m ^-2, ASA physical status III-V, colonoscopy and planned tracheal intubation. Thirty-day mortality was 1.2% (0.2% in electives and 6.0% in emergencies) and was associated with ASA physical status IV-V and emergency status.

CONCLUSIONS

Patients presenting for gastrointestinal endoscopy at a group of public university-affiliated hospitals where most sedation is managed by anaesthetists, had a high risk profile and a substantial incidence of significant unplanned intraoperative events and 30-day mortality.

Comparison of the effect of high versus low mean arterial pressure levels on clinical outcomes and complications in elderly patients during non-cardiothoracic surgery under general anesthesia: study protocol for a randomized controlled trial

BACKGROUND

Intraoperative blood pressure (BP) is a concern in daily clinic anesthesia and contributes to the differences in clinical outcome. We conducted a randomized controlled trial (RCT) to compare the effect of high vs. low mean arterial pressure (MAP) levels on clinical outcomes and complications in elderly patients under general anesthesia (GA).

METHODS

In this multicenter, randomized, parallel-controlled, open-label, assessor-blinded clinical trial, 322 patients aged more than 65 years will be randomized for a low-level MAP (60-70 mmHg) or high-level MAP (90-100 mmHg) during non-cardiothoracic surgery under GA. The primary outcome will be the incidence of postoperative delirium. The secondary outcomes will include the delirium duration days, intraoperative urine volume, intraoperative blood loss, specific postoperative complications, and all-cause 28-day mortality.

DISCUSSION

Results of this trial will help clarify whether BP management is beneficial for elderly patients under GA and will make clear whether the effect of high-level MAP can reduce the postoperative complication compared to low-level MAP.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02857153 . Registered on 15 July 2016.