TGIF

In the 1960s, a study estimated that 10,000 hospital patients per year were being killed by electrocution while being monitored or treated with electronic medical devices (including electrodes for EKGs). In fact, all electrical devices that carry current will "leak" some of this current into the surrounding environment, including the bodies of patients. While the design of medical equipment has been very much improved in order to lower the amount of current leakage and divert this current to the ground instead of to the patient, technicians remain responsible for ensuring that leakage will remain beneath the maximum safety threshold levels. Even with design improvements, however, much of the old equipment I'll be working on in Honduras may lack these innovations. Today in class, we were introduced to ways of testing the amount of current leakage from a given device using a digital multimeter, a tool that each group will have with them during the second month of the program.

Another commonly encountered problem with electronic medical equipment in the developing world is a faulty or incompatible power supply. For instance, in the United States and Canada, plugging into an AC power outlet will provide a current at 60 Hertz and approximately 120 Volts, but many other countries supply power at 220 Volts and 50 or 55 Hertz. Although Costa Rica, Nicaragua, and Honduras use the same power supply as the U.S., many hospitals with used equipment from places like Europe or Japan will have incompatible equipment. Today, we were taught ways of evaluating whether different kinds of 50 Hz devices are capable of running at 60 Hz. For some 50 Hz devices that cannot run at 60 Hz, we were taught ways of modifying the machine to work anyway. For 50 Hz devices that can run at 60 Hz, we were taught the limitations and constraints introduced by the mismatched frequency, as well as modifications that could help alleviate these problems.

A third electrical problem and commonplace source of equipment malfunction is the direction of current flow through the device. While three-pronged cords can only be plugged into an outlet in one particular way, a two-pronged cord, because of its symmetry, can be plugged in either the right way or upside-down. The result of plugging in a cord upside down is the reversal of the direction of current flow through the connected device. Though many simple devices (such as lightbulbs) are unaffected by this change, serious damage and safety hazards may result from the same error in more complicated appliances. For instance, many machines have a fuse in their circuitry before their main components, so that an overload of current will blow-up/fry the cheap fuse instead of the expensive machine. When current is reversed, however, it will pass through the fuse only AFTER it has already passed through the machine, risking extensive damage and causing a serious safety hazard. Even when a device is plugged in correctly, though, power outlets are often wired backwards accidentally, making the correct incorrect and rightness wrong. We were taught how to test for this issue and fix it when necessary.

During our lab after the lectures, my partner and I built an extension cord for use in our host hospital in Honduras the second month. Unfortunately, since most of today's course material was new to me (and because my partner was patient), we were one of the last groups to finish. Everyone waited for us, though, and we then went out exploring the city and experiencing the culture.

Shortly after leaving the Academy, which is one block from the Pan-American Highway, we were startled by an exceptionally close gunshot sound (within 20 feet), because the sound of a car backfiring is exactly the same as the sound of a gunshot. Throughout the group, we were all somewhat disappointed that no one had enough experience to immediately hit the deck in response to the sound, as we all simply stood in a haphazard glob. However, we are all now quite experienced in crossing several lanes of maniacal traffic, which should do for now.