Often medical supplies are expensive and difficult to get in developing countries. Even when hospitals and clinics have the machines to run certain tests, doctors may not be able to use them for a lack of supplies. For the electrocardiograph (ECG or EKG) machine, which is used to analyze heart function, Engineering World Health (EWH) devised a method to create reusable ECG pads from readily available materials.
The ECG machine measures the electrical charge emitted by the heart at each beat. Several pads are placed on the skin around the heart and are coupled to the body with an electrically conductive gel. These pads are connected to the ECG machine, which detect the heart’s electrical signal. Normally after such a test is conducted, the ECG pads are discarded. This means that the availability of ECG tests in many countries is tied to the number and availability of ECG pads. Engineering World Health’s ECG pads do not have to be thrown away after use; they can be boiled to sterilize them. And they can be produced in country from available materials.
Glass bottles with bottle caps all have a thin plastic liners attached to the cap designed to seal the cap against the neck of the bottle. For these reusuable ECG pads, the liners are removed from the bottle caps and a small X is cut into the center of the liner. Then the head of a small metal clothing snap is inserted through the hole in the cap liner. That’s it; the ECG pad is finished. This simple device, forming a small disc with the flat part of the snap on one side of the plastic liner and the nub of the snap on the other side, can be attached to an ECG machine to produce a reliable medical test. The electrically conductive gel needed to attach the pad to the patient can be made from water, flour and salt.