Tutorial 2: Case Study “Silent Warning” “Search of the Lost Cord” SY DE 142 – May 17, 2004 Introduction to Human Systems Engineering Waterloo, Ontario, Canada

Outline  Case Study: “Silent Warning”  Discussion on “Silent Warning”  Case Study: “In Search for the Lost Cord”  Discussion on “In Search for the Lost Cord

Silent Warning Overview  Time: January, 1972  Place: Iraq  Synopsis: Pesticide treated grain is shipped to Iraq, labeled in English. Local farmers grind the grain to make bread, poisoning themselves.

Silent Warning “Events” and their Cause  Dry weather caused low supplies of grain for a couple of summers before 1971  Imported grain was not distributed on time, caused a huge portion of the seeds to remain unused  The shipment of grain was treated with alkylmercury fungicide to inhibit spoilage by the main distributors, caused… (see next slide)

Silent Warning Results Between January and the end of August, 1972  6530 admissions and 459 deaths from methylmercury (based on the record of the hospitals)  60,000 peasants have suffered neurological damage (based on expert opinion and general observations by tourists)

Silent Warning Question  Give examples of some factors contributing to this “Accident”.

Silent Warning Analysis  Factors contributing to this “Accident”:  Label in English  Symbol not meaningful in their culture  The alkylmercury was not physically bound with the dye  Delayed effects, no immediate feedback  No taste or smell to differentiate

Silent Warning Discussion  Based on your analysis: What could have been done by Cargill Corporation of Minnesota to prevent this accident from happening?

In Search of the Lost Cord Overview  Time: December 1986  Place: Children’s Hospital, Seattle  Synopsis: Nurse plugged two connectors, one from the IV pump and other from EKG electrodes taped to the chest of a four-year-old girl and caused her electrocution.

Question  Use the Action Cycle to discuss what happened.  Goal, (intention)  Act (sequence, execution)  World (what happened)  Evaluate (perception, interpretation, evaluation)

Action Cycle for “The Lost Cord”  Goal: Monitor girl’s condition  Intention: Monitor her heart/ Use the EKG  Seq of Actions: Tape electrodes to chest Run lead across mattress Plug into heart monitor machine  Actions: does the above but plugs into IV pump instead (Gulf of Execution)

Action Cycle for “The Lost Cord”  World: girl connected to IV pump, flow of electricity running into girl’s body  Perception: seeing girl get electrocuted NOTE: Always indicate HOW the “world” is perceived by indicating senses maybe (v. such as sees, hears, etc.)  Interpretation: Wrong amount of electricity into girl / wrong piece of equipment  Evaluation: could not monitor girl’s condition / girl died NOTE: (you need to tie back to your goal)

Use Action Cycle to discuss what happened  A heart monitor machine was there to check the girl’s condition  Nurse picked up the EKG lead, then bent over and grasped the end of the cord hanging down near the side of the bed  The cord was from the IV pump and not the heart monitor machine, but the connectors had similar slots that matched