Dr. Abumrad went out of town and cancelled our meeting scheduled for November 10.

One of our group members met with Dr. William Grissom to discuss the implementation of a pH meter and motility sensor. We originally intended to include pH sensors at the tip of the tube in order to confirm placement in the stomach and small intestine as opposed to the lung. However, the error leading to placement in the lung occurs at the beginning of placement, and including a pH sensor would be an unnecessary expense.

Dr. Grissom suggested using a camera to show progression through the GI tract as opposed to using ultrasound. Ultrasound on the gastrointestinal tract is mostly unreliable and would be too expensive and difficult to implement into our design. Dr. Grissom also suggested other ways to measure motility and track placement. In the next meeting with Dr. Abumrad, we will be discussing potentially using a series of strain gauges to track movement through the GI system and video processing to calculate motility as well as ways to test future prototypes. These approaches would allow us to track where the tip of the tube has been, currently is, and will be based on changes in position and motility.

To proceed with using a camera for visualizing placement or even calculating motility, we will be meeting with Dr. Pietro Valdostri. Dr. Valdastri’s research centers around endoscopies. Because we will be following tube placement in a manner similar to an endscopy, consulting with Dr. Valdastri seemed appropriate. In addition, we will be discussing with Dr. Valdastri the possibility of using a typical endoscopic camera to detect gastric motility.

Another element of the project suggested by Dr. Grissom was to utilize electromyography to measure gastrointestinal motility. This technique has been used before, though primarily as a way to understand various gastric diseases, such as chronic idiopathic gastroparesis (Bortolotti, 1990). However, we believe that the same technique used in this paper could be incorporated into our design as a way to ensure accurate placement of the feeding tube.

Specifically, the authors of the paper inserted a probe into the gastrointestinal system. On the tip of the probe was a Plexiglass cup with a pair of Ag-AgCl needle electrodes. The length of the electrodes were completely coated except for the last 1 mm. The electrodes were placed 4 mm apart and soldered to shielded copper wire. An identical ground electrode was placed on the outer skin of the patient lying above the stomach. All of the electrical wires were contained within a 4.5 mm plastic tube and passed outside of the body. A pressure of -20 mmHg was applied to the tube to ensure that the electrode cup stayed sealed to the gastric lining. This setup is very compatible with our current design, as it already utilizes a tube. We also plan on removing the system following placement, so the wires will not interfere with feeding.