Decision Support for Intraoperative Low Blood Pressure

NCT ID: NCT02726620

Last Updated: 2019-05-16

Study Results

Results available

Outcome measurements, participant flow, baseline characteristics, and adverse events have been published for this study.

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Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

22435 participants

Study Classification

INTERVENTIONAL

Study Start Date

2017-01-05

Study Completion Date

2018-12-29

Brief Summary

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The purpose of this study is to determine whether a decision support system can improve the adherence to thresholds for low blood pressure by anesthesia providers, which in turn prevents their patients from having organ injury.

Detailed Description

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Blood pressure management is an important part of anesthesia. Many factors contribute to a change in blood pressure during a surgical procedure, such as blood loss, manipulation by surgeons, and there are several mechanisms through which anesthesia itself changes blood pressure. Although a high blood pressure also occurs during anesthesia, most of these factors lower a patient's blood pressure. When a patient's blood pressure becomes too low, the internal organs become at risk of receiving not enough blood (low perfusion or hypoperfusion). This low perfusion state can result in organ damage (ischemia) because of an insufficient supply of oxygen and glucose. Hence the important task of anesthesia providers to maintain the blood pressure of patients, using a wide range of drugs and other interventions.

A big challenge in blood pressure management is to know when a low blood pressure indeed results in low perfusion of organs. There is a large variation between patients in how susceptible they are to low blood pressure, as well as a difference between the organs in how easily they are damaged because of low perfusion. Elder patients, or patients with preexisting hypertension, heart problems or other cardiovascular diseases are more prone to a low blood pressure and are more likely to develop organ ischemia when there is a low blood pressure. The kidneys, the heart and the brain are the organs that are most at risk of organ damage. As one cannot measure the perfusion states of individual organs in individual patients, it is very difficult to know 'how low to go' with a patient's blood pressure.

Recent studies have used large datasets of patients to demonstrate that there is statistical association between low blood pressure during surgery and various types of organ injury. As patients are already treated for low blood pressure by anesthesia providers, this suggests that patients have low organ perfusion states despite the current treatment standards. A patient's blood pressure is not simply a dial that can be adjusted to a specific level. Finding the right level of interventions can be difficult in some patients. Consequently, lower blood pressures are common in anesthesia, even with the current standards of blood pressure management.

In this proposed study the investigators will implement two forms of decision support to assist anesthesia providers in blood pressure management. The decision support aims to educate anesthesia providers about the risks of low blood pressures in direct relation to the patients that they treat. One form of decision support will provide automated notifications through pagers and through the anesthesia information management system. These automated notifications pop up when the patient's blood pressure drops below a level that is associated with a risk of organ injury, and thus alerts the anesthesia provider of the blood pressure and its associated risk. The second form of decision support will send a postoperative email the day after the procedure when the patient has had a low blood pressure for particular duration. This email then provides feedback to the anesthesia provider by informing them of the increased risks of organ injury that are associated with that low blood pressure.

The study will look at both a change in patient outcome and a change in blood pressure management and will be performed at the Vanderbilt University Medical Center (VUMC). The change in patient outcome will primarily be studied through the occurrence of acute kidney injury in the first days following the procedure at the VUMC. The change in blood pressure management (provider behavior) will be studied by observing the depth and duration of low pressures during anesthesia, and the number of interventions that have been used to treat the blood pressure. Patient outcome will be studied by comparison of a baseline phase - before the decision support is implemented and uses historic data- and the intervention phase - the period during which the intervention is active. Only routinely collected clinical data will be used for these analyses: no additional data collection is required.

As it is impossible to know which form of decision support will be the most effective, the first three months of the intervention period will be a 'nested cluster-randomized trial'. The anesthesia providers (not the patients) will be randomized to either the automated notifications or the feedback emails. After three months all anesthesia providers will receive both forms of decision support for the remainder of the intervention period. The reason why anesthesia providers are randomized only during the first three months is that cross-over or contamination between the two groups is expected. This contamination could make it impossible to study the effect of the decision support on patient outcome, as there will be no longer any difference between the study groups.

Conditions

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Hypotension

Study Design

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Allocation Method

NON_RANDOMIZED

Intervention Model

SEQUENTIAL

It is an interrupted time-series of a decision support package intervention that aims to study the the effect of the decision support package on patient outcome. The effects of the individual decision support components of the package on healthcare provider behavior will be studied in a nested cluster-randomized trial: in the first month the attending anesthesiologists will be randomized to near-realtime notifications or feedback emails; in the second month in-room providers will be randomized to near-realtime notifications or feedback emails. Starting month four all providers will receive both near-realtime notifications and feedback emails.
Primary Study Purpose

PREVENTION

Blinding Strategy

NONE

Study Groups

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Hypotension decision support

The intervention period. Several decision support elements are implemented to notify anesthesia providers: attending anesthesiologists and in-room anesthesia providers of intraoperative hypotension (threshold of a mean arterial pressure below 60 mmHg). Two types of decision support will be implemented: near real-time decision support and feedback emails.

Near real-time decision support elements will notify the anesthesia providers of a blood pressure drop below the threshold and display the associated increased risk of acute kidney injury. The notification is presented through the pager system for attending anesthesiologists and through the anesthesia information management system for the in-room anesthesia provider.

All providers will be notified through email within 24 hours after the end of an anesthetic case, when the patient had an episode of intraoperative hypotension that is associated with an increased risk of organ injury due to organ ischemia.

Group Type EXPERIMENTAL

Attending real-time decision support

Intervention Type PROCEDURE

Near real-time decision support elements will notify the attending anesthesiologists of a blood pressure drop below the threshold for intraoperative hypotension (mean arterial pressure below 60 mmHg). The notification is presented through the pager system. The page will also display the associated increased risk of organ injury due to organ ischemia.

In-room real-time decision support

Intervention Type PROCEDURE

Near real-time decision support elements will notify the in-room anesthesia provider of a blood pressure drop below the threshold for intraoperative hypotension (mean arterial pressure below 60 mmHg). The notification is presented through the anesthesia information management system. The decision support system will display the associated increased risk of organ injury due to organ ischemia.

Attending feedback emails

Intervention Type PROCEDURE

Attending anesthesiologists will be notified through email within 24 hours after the end of an anesthetic case, when the patient had an episode of intraoperative hypotension (mean arterial pressure below 60 mmHg or lower for a particular duration) that is associated with an increased risk of organ injury due to organ ischemia.

In-room provider feedback emails

Intervention Type PROCEDURE

In-room anesthesia providers will be notified through email within 24 hours after the end of an anesthetic case, when the patient had an episode of intraoperative hypotension (mean arterial pressure below 60 mmHg or lower for a particular duration) that is associated with an increased risk of organ injury due to organ ischemia.

Anesthesia Information Management System (AIMS)

Intervention Type DEVICE

The anesthesia electronic record keeping system

Perioperative Data Warehouse (PDW)

Intervention Type DEVICE

The data warehouse that is used to gather perioperative data and create user reports. In this instance the PDW will be used to send the postoperative feedback emails.

General anesthesia

Intervention Type PROCEDURE

Any anesthetic drugs that are used to induce general anesthesia above the level of sedation.

Pager system

Intervention Type DEVICE

The mobile pager system through which alerts can be sent

Central neuraxial anesthesia

Intervention Type PROCEDURE

Regional anesthesia effectuated through the placement of local anesthetics around the nerves of the central nervous system, e.g. spinal anesthesia and epidural anesthesia.

Non-cardiac surgery

Intervention Type PROCEDURE

Any surgical intervention that is not aimed at surgical correction of the heart

Propofol

Intervention Type DRUG

Anesthetic drug used to maintain general anesthesia

Sevoflurane

Intervention Type DRUG

Anesthetic drug used to maintain general anesthesia

Desflurane

Intervention Type DRUG

Anesthetic drug used to maintain general anesthesia

Isoflurane

Intervention Type DRUG

Anesthetic drug used to maintain general anesthesia

Ephedrine

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Phenylephrine

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Norepinephrine

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Epinephrine

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Dobutamine

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Dopamine

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Isoproterenol

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Milrinone

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Atropine

Intervention Type DRUG

Cardiovascular drugs used to treat intraoperative hypotension

Glycopyrrolate

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Vasopressin

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Terlipressin

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Sodium Chloride 0.9%

Intervention Type DRUG

Intravenous fluid used to treat intraoperative hypotension

Ringer's lactate

Intervention Type DRUG

Intravenous fluid used to treat intraoperative hypotension

Hydroxyethyl starch solutions

Intervention Type DRUG

Intravenous fluid used to treat intraoperative hypotension

Fresh Frozen Plasma

Intervention Type DRUG

Intravenous fluid used to treat intraoperative hypotension

Packed Red Blood Cells

Intervention Type DRUG

Intravenous fluid used to treat intraoperative hypotension

Albumin solutions

Intervention Type DRUG

Intravenous fluid used to treat intraoperative hypotension

Plasma-Lyte

Intervention Type DRUG

Intravenous fluid used to treat intraoperative hypotension

Lidocaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Bupivacaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Levobupivacaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Ropivacaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Mepivacaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Tetracaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Prilocaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Procaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Chloroprocaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Benzocaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Articaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Usual care group

The 'before' period - or historic control group - during which no decision support for intraoperative hypotension was being used, also known as 'usual care'. This is the three year period prior to the intervention period (the 'Intraoperative hypotension decision support' arm).

Group Type ACTIVE_COMPARATOR

General anesthesia

Intervention Type PROCEDURE

Any anesthetic drugs that are used to induce general anesthesia above the level of sedation.

Central neuraxial anesthesia

Intervention Type PROCEDURE

Regional anesthesia effectuated through the placement of local anesthetics around the nerves of the central nervous system, e.g. spinal anesthesia and epidural anesthesia.

Non-cardiac surgery

Intervention Type PROCEDURE

Any surgical intervention that is not aimed at surgical correction of the heart

Propofol

Intervention Type DRUG

Anesthetic drug used to maintain general anesthesia

Sevoflurane

Intervention Type DRUG

Anesthetic drug used to maintain general anesthesia

Desflurane

Intervention Type DRUG

Anesthetic drug used to maintain general anesthesia

Isoflurane

Intervention Type DRUG

Anesthetic drug used to maintain general anesthesia

Ephedrine

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Phenylephrine

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Norepinephrine

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Epinephrine

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Dobutamine

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Dopamine

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Isoproterenol

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Milrinone

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Atropine

Intervention Type DRUG

Cardiovascular drugs used to treat intraoperative hypotension

Glycopyrrolate

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Vasopressin

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Terlipressin

Intervention Type DRUG

Cardiovascular drug used to treat intraoperative hypotension

Sodium Chloride 0.9%

Intervention Type DRUG

Intravenous fluid used to treat intraoperative hypotension

Ringer's lactate

Intervention Type DRUG

Intravenous fluid used to treat intraoperative hypotension

Hydroxyethyl starch solutions

Intervention Type DRUG

Intravenous fluid used to treat intraoperative hypotension

Fresh Frozen Plasma

Intervention Type DRUG

Intravenous fluid used to treat intraoperative hypotension

Packed Red Blood Cells

Intervention Type DRUG

Intravenous fluid used to treat intraoperative hypotension

Albumin solutions

Intervention Type DRUG

Intravenous fluid used to treat intraoperative hypotension

Plasma-Lyte

Intervention Type DRUG

Intravenous fluid used to treat intraoperative hypotension

Lidocaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Bupivacaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Levobupivacaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Ropivacaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Mepivacaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Tetracaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Prilocaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Procaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Chloroprocaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Benzocaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Articaine

Intervention Type DRUG

Local anesthetic used for central neuraxial anesthesia.

Interventions

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Attending real-time decision support

Near real-time decision support elements will notify the attending anesthesiologists of a blood pressure drop below the threshold for intraoperative hypotension (mean arterial pressure below 60 mmHg). The notification is presented through the pager system. The page will also display the associated increased risk of organ injury due to organ ischemia.

Intervention Type PROCEDURE

In-room real-time decision support

Near real-time decision support elements will notify the in-room anesthesia provider of a blood pressure drop below the threshold for intraoperative hypotension (mean arterial pressure below 60 mmHg). The notification is presented through the anesthesia information management system. The decision support system will display the associated increased risk of organ injury due to organ ischemia.

Intervention Type PROCEDURE

Attending feedback emails

Attending anesthesiologists will be notified through email within 24 hours after the end of an anesthetic case, when the patient had an episode of intraoperative hypotension (mean arterial pressure below 60 mmHg or lower for a particular duration) that is associated with an increased risk of organ injury due to organ ischemia.

Intervention Type PROCEDURE

In-room provider feedback emails

In-room anesthesia providers will be notified through email within 24 hours after the end of an anesthetic case, when the patient had an episode of intraoperative hypotension (mean arterial pressure below 60 mmHg or lower for a particular duration) that is associated with an increased risk of organ injury due to organ ischemia.

Intervention Type PROCEDURE

Anesthesia Information Management System (AIMS)

The anesthesia electronic record keeping system

Intervention Type DEVICE

Perioperative Data Warehouse (PDW)

The data warehouse that is used to gather perioperative data and create user reports. In this instance the PDW will be used to send the postoperative feedback emails.

Intervention Type DEVICE

General anesthesia

Any anesthetic drugs that are used to induce general anesthesia above the level of sedation.

Intervention Type PROCEDURE

Pager system

The mobile pager system through which alerts can be sent

Intervention Type DEVICE

Central neuraxial anesthesia

Regional anesthesia effectuated through the placement of local anesthetics around the nerves of the central nervous system, e.g. spinal anesthesia and epidural anesthesia.

Intervention Type PROCEDURE

Non-cardiac surgery

Any surgical intervention that is not aimed at surgical correction of the heart

Intervention Type PROCEDURE

Propofol

Anesthetic drug used to maintain general anesthesia

Intervention Type DRUG

Sevoflurane

Anesthetic drug used to maintain general anesthesia

Intervention Type DRUG

Desflurane

Anesthetic drug used to maintain general anesthesia

Intervention Type DRUG

Isoflurane

Anesthetic drug used to maintain general anesthesia

Intervention Type DRUG

Ephedrine

Cardiovascular drug used to treat intraoperative hypotension

Intervention Type DRUG

Phenylephrine

Cardiovascular drug used to treat intraoperative hypotension

Intervention Type DRUG

Norepinephrine

Cardiovascular drug used to treat intraoperative hypotension

Intervention Type DRUG

Epinephrine

Cardiovascular drug used to treat intraoperative hypotension

Intervention Type DRUG

Dobutamine

Cardiovascular drug used to treat intraoperative hypotension

Intervention Type DRUG

Dopamine

Cardiovascular drug used to treat intraoperative hypotension

Intervention Type DRUG

Isoproterenol

Cardiovascular drug used to treat intraoperative hypotension

Intervention Type DRUG

Milrinone

Cardiovascular drug used to treat intraoperative hypotension

Intervention Type DRUG

Atropine

Cardiovascular drugs used to treat intraoperative hypotension

Intervention Type DRUG

Glycopyrrolate

Cardiovascular drug used to treat intraoperative hypotension

Intervention Type DRUG

Vasopressin

Cardiovascular drug used to treat intraoperative hypotension

Intervention Type DRUG

Terlipressin

Cardiovascular drug used to treat intraoperative hypotension

Intervention Type DRUG

Sodium Chloride 0.9%

Intravenous fluid used to treat intraoperative hypotension

Intervention Type DRUG

Ringer's lactate

Intravenous fluid used to treat intraoperative hypotension

Intervention Type DRUG

Hydroxyethyl starch solutions

Intravenous fluid used to treat intraoperative hypotension

Intervention Type DRUG

Fresh Frozen Plasma

Intravenous fluid used to treat intraoperative hypotension

Intervention Type DRUG

Packed Red Blood Cells

Intravenous fluid used to treat intraoperative hypotension

Intervention Type DRUG

Albumin solutions

Intravenous fluid used to treat intraoperative hypotension

Intervention Type DRUG

Plasma-Lyte

Intravenous fluid used to treat intraoperative hypotension

Intervention Type DRUG

Lidocaine

Local anesthetic used for central neuraxial anesthesia.

Intervention Type DRUG

Bupivacaine

Local anesthetic used for central neuraxial anesthesia.

Intervention Type DRUG

Levobupivacaine

Local anesthetic used for central neuraxial anesthesia.

Intervention Type DRUG

Ropivacaine

Local anesthetic used for central neuraxial anesthesia.

Intervention Type DRUG

Mepivacaine

Local anesthetic used for central neuraxial anesthesia.

Intervention Type DRUG

Tetracaine

Local anesthetic used for central neuraxial anesthesia.

Intervention Type DRUG

Prilocaine

Local anesthetic used for central neuraxial anesthesia.

Intervention Type DRUG

Procaine

Local anesthetic used for central neuraxial anesthesia.

Intervention Type DRUG

Chloroprocaine

Local anesthetic used for central neuraxial anesthesia.

Intervention Type DRUG

Benzocaine

Local anesthetic used for central neuraxial anesthesia.

Intervention Type DRUG

Articaine

Local anesthetic used for central neuraxial anesthesia.

Intervention Type DRUG

Other Intervention Names

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Regional anesthesia Spinal anesthesia Intrathecal anesthesia Subarachnoid anesthesia Epidural anesthesia Central neuraxial blockade Lignocaine

Eligibility Criteria

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Inclusion Criteria

* 60 years and older
* Inpatients
* Scheduled for a non-cardiac surgical procedure under general or central neuraxial anesthesia

Exclusion Criteria

* Pre-existing end-stage renal disease: operationalized as a preoperative need for dialysis
* The following surgical procedures: renal surgery, cardiac surgery, organ transplantation, ophthalmic surgery, endoscopic gastrointestinal procedures, and (interventional) radiologic procedures.
* small non-invasive or minimally-invasive procedures will also be excluded, operationalized as excluding procedures with a surgical time of less than twenty minutes.
Minimum Eligible Age

60 Years

Maximum Eligible Age

100 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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UMC Utrecht

OTHER

Sponsor Role collaborator

Vanderbilt University Medical Center

OTHER

Sponsor Role lead

Responsible Party

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Jonathan Wanderer

Medical Director of Procedure Preparation Center

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Jonathan P Wanderer, MD, MPhil

Role: PRINCIPAL_INVESTIGATOR

Vanderbilt University Medical Center, Department of Anesthesiology

Locations

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Vanderbilt University Medical Center

Nashville, Tennessee, United States

Site Status

Countries

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United States

Provided Documents

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Document Type: Study Protocol and Statistical Analysis Plan

View Document

Other Identifiers

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160131

Identifier Type: -

Identifier Source: org_study_id

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