A personal incident

[July 21, 2010 NOTE: this was written years ago concerning an incident that happened years ago. I certainly  hope things like this are now less likely to occur. I must say, it left a mark on me.] My first encounter with a major safety issue involved lessons that were hard learned. The following incident occurred sometime in October, 1979, the year I began working in clinical engineering as a service technician.

The Biomedical Engineering Department received a call that an external pacemaker was not functioning in a procedure room next to the CCU. I arrived with a Medtronic pacemaker tester and found several cardiologists including the Director of Cardiology engaged in an attempt to stabilize a 57 year old male patient who had begun experiencing repeated and prolonged ectopic beats.

During the half hour or so that I observed this effort, clinicians tried, and I tested 3 pacemakers along with 3 pacing electrodes and found them all to be in working order. Even though all equipment was found to be in working order, no capture of pacing was observed on the continuous EKG strip running during the resuscitation attempt. The patient continued to deteriorate and I decided to take one of the sets of electrode and pacemakers back to our Biomedical Engineering lab for further examination.

While riding in the elevator I tried connecting the electrode to the lead wire connecting block, and found that the electrode did not appear to be fully inserted (a section of electrode contact area was exposed). In the lab, I confirmed this using an ohm meter, and quickly returned to the CCU treatment room only to find that the patient had expired.

Later examination of the lead wire connection block on several new units showed a molding irregularity on the lead wire end of the block. All of the units inspected had a plastic molding of a lesser diameter on that side. This resulted in the electrode not making contact with the connector screw if both screws were backed off the same number of turns (about 4 or 5). In other words, because the end screw was effectively seated lower in the block, the same number of turns could result in the electrode passing under the first screw, but butting up against the 2nd, thus not making positive contact with that connector.

Linked below are reporting forms and other documents relating to this incident.

The original incident report.

The electrode package.

The instructions.

Our second letter.

The USP letter.

The manufacturer’s letter.

Conclusion letter.

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