A project report on the design of the autobag device that performs the compression of the bag-valve-mask.

Abstract

The major tool used in resuscitation is the ambu bag, which requires at least two health workers to use and is tiresome to use making it less effective especially in areas with a very small patient to doctor ratio. This leads to delays in performing resuscitation causing the development of hypoxia and other complications. To solve this issue, the autobag was developed to automate the bag compression and reduce the number of health workers required to use it. To develop the autobag prototype, material selection and engineering analysis was first performed. Based on the analysis, the autobag device was fabricated using both 3d printing technology and woodworking. Post completion of the initial prototyping and testing phase of the first prototype, it was seen that the device was not able to meet the set acceptance criteria such as tidal volume, weight, and dimensions leading to modifications to the autobag design. The first modification included the use of less dense and light pinewood as the casing material decreasing the overall weight to 4.1kg. Other modifications included a bottom compartment to house and protect electronics and the addition of hooks to allow the device to be latched to bed frames. The modifications decreased the overall device dimensions to 33.4cm x 13.2cm x 19.8cm. A 35kg/cm torque servo motor was also used in place of the 11kg/cm servo motor such that the necessary torque to compress the ambu bag could be generated. An external 6.0V power supply and a 9V battery were added to power the servo motor and Arduino board respectively were added. A performance test was conducted to determine the tidal volume and number of breaths delivered which resulted in 560ml and 12 breaths per minute respectively. Feedback from the clinical client was also recorded who appreciated the overall weight and dimension reduction and acknowledged the addition of a switch that would ease device operation. Modifications made to the autobag device were able to address the shortcomings of the first prototype fulfilling all the set acceptance criteria. However, other tests such as safety tests, sterilization tests, and component stress tests must be done to holistically assess the device before deployment.