We have addressed (for example here and here) a number of what seem to be astonishingly difficult problems which face those who attempt to use HL7 CDA for coherent coding of clinical information.
In his "Critical Safety Issue for the PCEHR", Eric Browne makes clear why such problems may be of more general interest. Eric is talking here about the Australian Personally Controlled Electronic Health Record, but his warning (in bold below) is of much broader significance:
One major problem with HL7 CDA, as currently specified for the PCEHR, is that data can be supplied simultaneously in two distinct, yet disconnected forms – one which is “human-readable”, narrative text displayable to a patient or clinician in a browser panel; the other comprising highly structured and coded clinical “entries” destined for later computer processing. The latter is supposed to underpin clinical decision support, data aggregation, etc. which form much of the justification for the introduction of the PCEHR system in the first place. The narrative text may appear structured on the screen, though is not designed for machine processing beyond mere display for human consumption.
Each clinician is expected to attest the validity of any document prior to sharing it with other healthcare providers, consumers or systems, and she can do so by viewing the HTML rendition of the “human-readable” part of the document ( see the example discharge summary here). However, the critical part of the document containing the structured, computer-processable data upon which decision support is to be based is totally opaque to clinicians, and cannot be readily viewed or checked in any meaningful way. Moreover, I know of no software anywhere in the world that can compare the two distinct parts of these electronic documents to reassure the clinician that what is being sent in the highly structured and coded part matches the simple, narrative part of the document to which they attest. This is due almost entirely to the excessive complexity and design of the current HL7 CDA standard.
It seems to me that we are in grave danger of setting in train a collection of safety and quality time bombs, spread around Australia in a system of repositories, with no understanding of the clinical safety, quality and medico-legal issues that might be unleashed in the future.
As an illustration of the sort of problems we might see arising, I proffer the following. I looked at 6 sample discharge summary CDA documents provided by the National E-health Transition Authority recently. Each discharge summary looked fine when the human-readable part was displayed in a browser, yet unbeknownst to any clinician that might do the same, buried in the computer-processable part, I found that each patient was dead at the time of discharge. One patient had been flagged as having died on the day they had been born – 25 years prior to the date that they were purportedly discharged from hospital! Fortunately this was just test, not “live” data.