Senior design team helps hospital staff regulate bed angle

MechSE seniors Jacob Avery, Anthony Cao, Noah Durham, Alexander Molnar, and Brennan Sugg created a device that not only detects the angle of the head of a hospital bed, but continuously logs its angle and alerts staff whenever the bed has been out of an ideal position for too long. The design and production of this device was part of the MechSE senior design class, ME 470, and sponsored by Carle Foundation Hospital.

The optimal position of an ICU bed is known as "Fowler's position," defined as 35-45 degrees from the vertical. If the patient is out of Fowler's position for extended periods of time, complications may arise including pulmonary edema or pneumonia, which could be very serious depending on the condition of the patient.

"Our primary goal was to provide Carle a user-friendly tool that would increase their hospital staff compliance in maintaining the beds at Fowler's position," Avery said. "We've developed a multi-level design, the first being a head-of-bed angle sensing system, attachable to the ICU bed, the second being a data-processing package at a local computer."

Using a gyroscopic accelerometer, a sensor inside the device reads the bed angle data into a microcontroller, which converts the analog data into digital serial data. The angle is displayed at the front of the device on an LCD screen, and is sent through a wireless transmitter to a data-collecting program on a local computer. If the bed is outside of Fowler's position for more than 15 minutes, a bright blue flashing LED on the device is activated. The choice of a bright blue LED as an alert mechanism was very deliberate.

"In an ICU, there's lots of buzzers and lights blinking, lots of stuff going on, it's a very chaotic environment," Sugg said. "With respect to that, Carle has asked specifically for no audible alarms and no red lights. So we wanted something that was subtle, but distinct enough to catch the eye of a staff member walking by."

If the bed is purposefully set out of Fowler's position for any reason, the nurse or doctor can press the LED button. This restarts the timer and gives another 15 minutes of being out of Fowler's position before it starts blinking again.

The data-collecting program was designed to be very user-friendly. A staff member can check-in and check-out patients with only their name, patient ID and bed number, and the program can run in the background continuously. This data can be studied in an Excel template that includes several pre-made graphs and plots.

The team's device is very unique in that there is no product like it on the market. There is no other device that attaches to the ICU bed without being a large and integrated part of the bed itself, and none that use wireless data transmission to continuously log their data. The team's device is extremely practical in that it is a small device that can be attached to any normal ICU bed, takes little power, and wirelessly transmits the data to a pre-made program that automatically analyzes the data.

The device is initially intended for use in a study of compliance rates with Fowler’s position at Carle Foundation Hospital.

Funding for the project was provided by Shell Oil Company.