Medical Data Recorder

Medical data recorder from Martijn Kriens

Patient safety in hospitals is a huge issue and has been for many years. In the Netherlands alone more than 3% of all admissions lead to avoidable damage done to patients due to avoidable errors. More than 50% of those avoidable errors are related to the operating room. In total 1000 people die unnecessary due to avoidable errors in the operating room. This percentage has not changed significantly since the first study into hospital safety in 1991 ((1) The Harvard study based on 1984 data) and later in the book (2) “To Err is human” (2000).

At the core of this is the fallacy of the infallible doctor. Doctors (and especially surgeons) are not used to sharing the errors they make. This leads to the fact that individual surgeons learn from their errors but that the system as a whole does not. This effect is strengthened due to the strong hierarchical culture that student surgeons are submitted to.

In the past the aviation world suffered from the same problems. After the crash at Tenerife where 583 people were killed pilots have reversed their culture and way of working to be much more systematic and safe. At the core of this change are two issues: the “black box” and “Crew Resource Management” (CRM). After a crash everybody has his or her own version of the truth. Human memory is not very reliable under stress. An objective storage from where the reality can be retrieved in great detail is important for analysis. The Flight Data Recorder is an important tool to recreate the truth. The second issue is the realization that errors are often not based in the skill of the pilot but in the cooperation and communication with team members and others. This realization led to the creation of CRM where people are specifically trained to work together with others.

The comparison how aviation has improved safety to how doctors can improve safety is gaining more and more attention. The World Health Organization has proved that the use of a pre-surgical checklist (Time Out Procedure) saves a significant amount of lives. Slowly but surely elements of CRM are implemented in hospitals all over the world. As is shown in the Surpass study this has led to some decrease in avoidable adverse events in the hospital. However, the activities in the operating room are now responsible for more than 50% of the avoidable errors in the hospital.

However, in aviation CRM was only one half of the improvement that led to safety. The other part, the Flight Data Recorder, was just as important. In hospitals there is no “Medical Data Recorder” (MDR) yet. Research shows that operation reports written by surgeons after the operation are faulty in more than 70% of the reports due to the fallible nature of the human memory. This means that analysis on what went wrong often uses faulty operation reports as the basis for the analysis. Everybody can understand that faulty input leads to unreliable conclusions.

(1) (1991). Incidence of adverse events and negligence in hospitalized patients: results of the Harvard Medical Practice Study I. The New England journal of medicine, 324, 145–152.

(2) Kohn, L. T., Corrigan, J. M., & Molla, S. (2000). To Err Is Human.


In order to enable the objective analyses of all activities in the operating room it is important to collect all relevant information in one timeline: video, audio and sensory data of the patient (blood pressure, anesthetics, heart rate, etcetera). For this the medical data recorder consists of three camera’s, three microphones and a connection to the anesthetics machine. Alle data is stored in a computer to enable a thorough analysis.

The most important feature of the software of the Medical Data Recorder is to enable easy analyses. Operations often take several hours. Looking at several hours of several video and audio streams is too time consuming to be done regularly. The MDR makes this easier.

Basis for this MDR software is Observer XT, software from a company Noldus Information Technology. This software is developed for and used for more than 20 years in research in behavioral science. This software and hardware setup is now used in several operations to determine the best configuration.

The innovation is not so much in the technology itself but in it’s adaptation to this environment and the role that it plays in changing the way surgeons learn and implement their learning’s in daily life.