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The MIMIC II Clinical Database
Overview: MIMIC II Data Sources and Repositories
The MIMIC II Database is being created by an ongoing NIH-sponsored Bioengineering Research Partnership (NIBIB BRP 5RO1EB001659) including investigators at MIT, Philips Medical Systems, and Boston's Beth Israel Deaconess Medical Center. The MIMIC II project is aimed at integrating data, models, and reasoning in critical care.
The project gathers and edits data from
- intensive care unit (ICU) medical information systems (records of observations, measurements, and interventions performed in the ICU);
- hospital medical information systems (laboratory test results, medications ordered, and admission and discharge summaries); and
- bedside ICU monitors (physiologic signals such as ECG, blood pressure waveforms, and respiration; time series of physiologic parameters such as heart and respiration rates; and annotations that mark a subset of events of clinical significance, such as tachycardia and apnea).
- the MIMIC II Clinical Database (this database), based upon data obtained from the ICU and hospital medical information systems
- the MIMIC II Waveform Database (the companion to this database), based upon data obtained from the bedside monitors of a subset of the MIMIC II Clinical Database patients.
As part of the de-identification process, we have replaced all dates in these records with surrogate dates, most of which (for the next several years, at least) are in the future. In January, 2009, the surrogate dates were revised in order to restore the original temporal relationships within sets of records all belonging to the same patient (typically as a result of multiple admissions); thus, for example, two records acquired from the same patient, separated by a gap of six months, have surrogate dates that are likewise separated by a six-month gap. Records acquired from different patients on the same date, however, generally have different surrogate dates.
As of October 2008, the project had collected data from about 30,000 patient admissions (from over 26,000 patients) for the MIMIC II Clinical Database, and data from bedside ICU monitors for about 4,000 of these patients for the MIMIC II Waveform Database. Each record typically covers a patient's entire stay in an intensive care unit (typically a few days, but in many cases a week or more).
Read Using the MIMIC II Database for a tutorial introduction including additional background, links to available software, hints on finding data of interest with these collections, and much more.
The MIMIC II Clinical Database
A limited distribution of 26,588 patient records is available to qualified researchers under terms of a data use agreement; details are here. The non-text portions of another 110 records are available as part of the training and test data sets for the PhysioNet/Computers in Cardiology Challenge 2009. Additional records are still being collected and prepared for inclusion in the database, and will be made available in the future.
Each record in the MIMIC II Clinical Database contains information about a single patient. About 11% of the patients have been admitted to one or more of our study ICUs more than once, and their records contain information about all of these admissions, supplemented by limited additional information collected during the intervals between ICU admissions. (In the MIMIC II Waveform Database, however, each record contains information for only a single ICU admission.)
We provide the MIMIC II Clinical Database in several formats, with plans to support more in the future. Currently, each record is contained within a subdirectory of this one. By visiting any of the numbered directories listed below, it is possible to get a view of the record in chronological order, and this may be useful to obtain an overview of the record. The same information is contained in a WFDB annotation file within each directory, and also in a plain text file, and either of these formats will be more easily parsed by a computer program than the default (HTML) view. In the near future, we will provide a mechanism for selecting a desired set of records and downloading them into a relational database for further analysis.
Many of the timestamps that appear in the MIMIC II Clinical Database were manually entered into the ICU medical information systems as much as an hour after the events to which they refer, and others were extracted from laboratory reports that became available at varying times following the test. In such cases, the MIMIC II Clinical Database includes both the time of data entry (the time at which the information was first available in the medical record) and the best available estimate of the time of the event or test itself. These times are not perfectly synchronized with those in the corresponding MIMIC II Waveform Database records, as a result of imperfect synchronization of clocks as well as imprecise or faulty recall, and occasional transcription errors in manual entry. As a result, one should not assume that the time order of events separated by 15 minutes or less is known; for example, an intervention recorded in the clinical database may appear a few minutes earlier than the event in the waveform database that prompted the intervention.
First-time users of the MIMIC II Database will find much useful information in our tutorial, Using the MIMIC II Database.
The MIMIC II Waveform Database
The first 4164 records of the MIMIC II Waveform Database are available now. Visit the home page of the MIMIC II Waveform Database for additional information. (Please note that not all of the PhysioNet mirrors provide access to the MIMIC II Waveform Database, because of its very large size. If the link above does not work, please try this alternate link hosted on the master PhysioNet server.)
Name Last modified Size Description
Parent Directory -
ANNOTATORS 27-Jan-2009 02:33 39 list of annotators
MAP 05-Feb-2009 03:51 98K
dictionaries/ 03-Feb-2009 12:25 -
software.tar.gz 11-Feb-2009 01:56 10K
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