Circulation 36,475 • Volume 16, No. 2 • Summer 2001

The Role of Information Systems in Anesthesia

Daniel M. Thys, MD

In a knowledge-based society, information is the skeleton around which organizations are designed.1 Although anesthesiology, as a field, is embracing a growing number of new activities, the intra-operative management of the surgical patient remains the “primary” or “core” activity of our specialty. It is, therefore, perplexing that in the increasingly digital Information Age, information concerning our most essential activity continues to be documented in an analog format that relies predominantly on paper and pen. Indeed, it is estimated that, today, no more than 50 departments of anesthesia or 1% of all departments in the United States have invested in and use Anesthesia Information Management Systems (AIMS).

The purposes of this review are to: 1) define what comprises an AIMS, and 2) describe why AIMS are essential for the practice of anesthesiology.2

What is an Anesthesia Information Management System?

In its most basic meaning, an AIMS is a computer system that captures anesthesia-related information in a digital format.3,4 One of its essential components is the Automated Anesthesia Record keeper (AAR) that collects information on anesthesiology’s intra-operative activities. An AAR alone, however, does not qualify as an AIMS as it does not allow one to use anesthesia information for management purposes.

What does an AIMS do?

An AIMS gathers information on virtually every patient with whom a department of anesthesia interacts. The information is primarily intra-operative information, but should, preferably, also include data from the perioperative period. The information is pooled in a database where it is stored and can be arranged in a format that allows analysis. The AIMS database may interface with other databases in the hospital or those of a larger health care delivery system.

What are the components of an AIMS?

1) Hardware: Information enters the AIMS through input devices. Data acquisition devices can automatically collect data such as hemodynamics, capnography and anesthetic gas analyses, Hb oxygen saturation, and some ventilator settings. Other devices are designed for manual input of data such as drug and fluid administration, interventions, and observations. Common input devices for manual entry include the keyboard, touch screen, mouse or trackball, and bar code scanner. Microphones connected to voice recognition devices are also under evaluation. Once the data are acquired, devices are needed to store the data and rapidly retrieve it for analysis and reproduction. Because databases often pool data from multiple recording stations, the data need to be transmitted to a central location by networking devices. At the central location, a file server further serves as a storage vehicle within which the data can be organized, stored, and replicated. Storage devices commonly consist of optical disks, large capacity hard drives, and groups or arrays of hard drives. For long-term storage and backup, magnetic tapes are frequently utilized. The data also need to be readily accessible for display, reproduction or analysis. At present, file servers are most commonly accessed via personal computers and the data are reproduced by printing an anesthesia record, spread sheet, or structured report.

2) Software: While the hardware components used in AIMS are mostly standard commercial products made suitable for the AIMS tasks by minimal adaptation, software designed for the input and handling of the anesthesia information is very specific to our specialty and the way we work. Processes that the software needs to be able to perform include the recognition of anesthesia-related data, the rejection of artifacts, the sorting of the data in a time-ordered or other logical sequence, formatting of the data for storage, replication, and analysis. At present, the printed reports are still truly unique and resemble the format of manual anesthesia records rather than standard computer-generated reports. In addition, software programs are needed to control the flow of data between the various components of the network. Analysis of the data can be conducted using either proprietary analysis programs or standard database and spreadsheet programs.

Why are AIMS essential for the practice of anesthesia?

Individual Patient

1) Better care through better records: The essential purpose of maintaining an anesthesia record is to document how an individual patient responds to anesthesia and surgery. The information is permanently stored in the medical record for the patient’s benefit and to allow other practitioners to care for the patient in a more informed manner. Therefore, the more accurate the recorded information, the greater the likelihood that the care will be tailored to the patient’s individual needs. One can postulate that the accurate recording of a patient’s responses to anesthetic interventions will lead to better patient outcome. Several published reports have shown that automated anesthesia records are more accurate than manual records.5,6,7 In addition, the storage of anesthesia records in a digital database allows the rapid and easy retrieval of a patient’s previous anesthesia records.

2) Better ergonomics for the anesthesiologist: In the operating room, anesthesiologists face a complex environment. They need not only to assimilate multiple information inputs, but also to nearly instantaneously integrate, analyze and prioritize these to respond appropriately. Record keeping often represents a significant distraction from more immediate patient care needs. It is estimated that the time occupied by record keeping comprises 10 to 15% of the total anesthesia time.8 While some authors have found that automated record keeping significantly reduces the record keeping time,9 not every investigation has confirmed this. There is agreement, however, on the observation that vigilance is not negatively affected by automated anesthesia record keeping and that anesthesiologists are better able to organize their intra-operative activities when automated record keeping is utilized.10 Manual entries into the automated record are performed at times of less intense activity without great loss in overall data accuracy since most of the data collection is automatic and continuous. It has even been argued that with automated anesthesia record keeping the anesthesiologist shifts his/her activities to higher, cognitive level, supervisory tasks.11

Anesthesia Practice

1) Quality Assurance function: The analysis of intra-operative incidents is facilitated when automated records are used. Indeed, the automated records tend to contain more data than manually kept records. In addition, the continuously available data are sampled more frequently and are more accurate than on manual records. A specific benefit of AAR is their ability to accurately time various intra-operative events (e.g. did desaturation precede bradycardia or bradycardia precede desaturation?). A concern that has been raised in connection with incident analysis is related to the confounding role of data artifacts and potentially false or misleading conclusions caused by them. In a large study of automated records, artifacts were readily recognized by the investigators when they reviewed both the printed records and the digital database.12 In addition, AIMS allows the rapid scanning of a large database for specific incidents. Therefore, trends in certain incidents can be identified and their occurrence with individual physicians can be profiled.

2) Outcomes assessment: The availability of digital information on a large number of patients allows one to more readily tie specific patient characteristics or intra-operative events to patient outcomes. Meaningful outcomes analysis often relies on the study of a large number of patients. For some outcomes, a single institution may not have a sufficient patient volume to conduct scientifically valid outcomes analysis. Databases that are in digital format can easily be shared among several institutions and in this manner the power of a particular analysis can be increased. Managed care organizations are also interested in patient outcomes. The availability of anesthesia information in digital format permits its integration with the hospital’s other databases. As such, information about anesthesia care can be incorporated in a patient’s record of total care and the role of anesthesiology in affecting overall patient outcomes can be assessed. In addition, the effects of variations in the practice of anesthesia by individual physicians can be analyzed.

3) Education: Intra-operative events are readily retrieved from a digital database and reproduced in a manner that allows their thorough analysis. Continuous data that are recorded automatically, are often stored with a high temporal resolution. Once reproduced, they can easily be used for educational purposes. The meticulous analysis of a sequence of events may provide insights that are not immediately obvious from the study of manual records.

4) Medico-legal protection: While there are no readily retrievable reports on the use of automated records in court proceedings, as a general principle, accurate information will most often work to the advantage of a defendant, one way or another. The automated record provides unbiased and contemporaneous documentation of intra-operative events. It may help refute claims of negligence and allow one to positively demonstrate that intra-operative responses were logical and appropriate for a given event. While security of the data and the possibility of post-hoc tampering are major concerns, most manufacturers of AIMS have been able to address this problem successfully.

Management Function

1) Tabulation of services rendered: The exact tabulation of daily anesthesia activities can be a considerable challenge, particularly in large anesthesia departments with multiple anesthetizing locations. An AIMS with workstations in all the settings where anesthesia services are provided greatly facilitates the compiling of such data. Not only can reports be generated that summarize the daily anesthesia activity, but the precise duration of each of the activities can also be measured. The information of individual patients can be forwarded automatically to a billing service for the prompt processing of charges.

2) Costs: In most anesthesia departments, drugs and supplies represent major budgetary expenditures. Adoption and implementation of an AIMS offer the possibility to analyze the utilization of drugs and supplies in a systematic manner. Consumption of such resources can be categorized in multiple formats such as per patient, per case, per surgical category, per anesthesia type, per physician, per operating room, etc. While practice guidelines can be developed to encourage cost-efficient drug-utilization, compliance with guidelines is best verified through scanning of an AIMS database. In a recent report, investigators at Duke University estimated that such an approach had resulted in generating recurring pharmaceutical savings of approximately $ 1,000,000 per year.13

3) Resource utilization: The exact time at which various perioperative events take place is documented with great precision by an AIMS. The AIMS database, therefore, contains large amounts of information that permit the tracking of resource utilization. For every case, the times of admission to the operating room, of induction, of surgical incision, etc. are recorded and stored. From this information, it is possible to derive OR utilization data by service, by surgeon, or by CRNA/anesthesiologist. In addition, it is possible to clearly document the time allocation of individual anesthesiologists and to confirm that Medicare concurrence regulations are followed and documented.

4) Compliance with accreditation agencies: Most health regulatory and accreditation agencies mandate that comprehensive records be maintained for every patient encounter. A secondary requirement is that the records be legible. Many anesthesiologists have had unpleasant encounters with JCAHO or State Health Department surveyors because these stipulations were not met. The ability to produce a legible anesthesia record on every patient who received anesthesia services is highly appreciated by most surveyors.

For training programs in anesthesia, the Residency Review Committee of the ACGME has recently published specific numbers of various cases that each resident must perform to fulfill the American Board of Anesthesiology’s training requirements. Compliance with these requirements is easily achieved and verified when all anesthesia records are stored in a digital database. Individual resident assignments can be tailored to each resident’s need for specific types and categories of cases.


A gradual move towards automated information systems and resulting databases is just as inevitable in anesthesia as it has been in other areas of health care and industry. The balance between limited resources and increasing demand for service will propel the trend towards maximally effective utilization of available resources will continue and the need for accurate related data will accelerate. At the present time, digital systems provide the only practical method to store and analyze large amounts of data and they are, therefore, essential components of a modern anesthesia environment. The perfect AIMS does not yet exist. Current commercial systems are, however, well-developed and provide their users with an early entry into a digital world that is inescapable. Anesthesiologists who embrace this new technology place themselves at a significant competitive advantage. The initial price is high, but the potential rewards are enormous.

Dr. Thys is Chair, Department of Anesthesiology, St. Luke’s-Roosevelt Hospital Center and Professor, Department of Anesthesiology, Columbia University, New York, N.Y.


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