Drape Plate Electrical Connection

Preserving sterility in the operating environment is a foremost priority. The drape system is responsible for creating a physical barrier between capital and disposable equipment while facilitating electrical and mechanical connections.

Introduction

While the camera and instruments pose engaging technical tasks, I was also fortunate enough to work on projects outside of the disposables. Namely, the draping system.

A general procedure will see surgeons and technicians position the capital equipment relative to the patient (dock), cover the capital equipment with a sterile film barrier (drape), and initiate the procedure.

As stated, both the camera and instruments are single use medical devices. The capital equipment, conversely, is to be used indefinitely. The challenge lies in preserving cleanliness of the capital equipment and sterility of the operating environment.

It is impossible to sterilize the capital equipment given the sensitivity of its enclosed electronics. Thus, it is required that this equipment be protected from contaminants in the OR, yet more important is that the OR remains uncontaminated from potentially non-sterile capital equipment. This could lead to a break in sterility of the surgical technicians which poses a serious threat to the patient
This barrier is achieved through the use of drapes. These are thin film covers that are, of course, draped over the capital equipment. However, there remain interface points where disposables must be attached to capital equipment to facilitate mechanical and electrical connections. In the case of the vicarious system, this is achieved through the drape plate.

Design & Development

Early designs of the drape plate utilized a number of screws to attach to the draping interface on the patient cart. This is unacceptable for a product-level design.
In order to facilitate a simple and understandable attachment method, we developed a folding and latching mechanism. Since alignment between the drape plate and patient cart is crucial, a number of guide features were implemented. These are intended to reduce the need for the user to visualize the attachment point and streamline the draping process.
As stated, the drape plate must facilitate an electrical connection between the camera control housing and the patient cart. This poses a challenge as it is crucial that no added user input, such as cleaning, is required to facilitate this connection. This means it should be robust against debris that might be present in an operating environment.
Furthermore, due to the pivoting action required by the chosen latching mechanism, there is no sliding connection between male and female electrical components.
This requires a high level of compliance in the electrical hardware that is to be used to create the connection. To accomplish this connection, we worked intimately with a vendor to develop a custom connector to bridge the gap between disposable and capital.
While compliance is necessary, so is ensuring a proper connection. Tolerances on the connector itself and surrounding components created a challenge in securing the connection.

Testing & Evaluation

This project required diligence in a number of areas. Namely, ergonomics/human factors, tolerance analysis, electrical testing and even moldability analyses for the components comprising the drape plate.
Prototypes were designed and manufactured either through 3D printing or machining of certain plastics. These were tested on a prototype patient cart for usability. Results from human test users drove further iterations of the design to a point where after 1-2 attempts, most could achieve the connection without looking at the interface.
Collaboration with the electrical vendor continued as certain details were agreed upon such as allowable materials, sterilizability of the connector, allowable tolerances and signal integrity.
The draping process was a highlight in a recent formative study which saw a number of certified operating room technicians give their personal feedback on the draping process. Their suggestions proved invaluable as their experience with other systems gave them a clear vision of what is desirable in an operating room environment. I learned that users will treat the product with a lot less tenderness than I do!

Conclusion

Involvement in the drape plate development exposed me to new disciplines that I hadn’t experienced before. My largest takeaway was the importance of human factors in the consideration of a design intended to facilitate a clear mechanical latching connection. What made sense in CAD didn’t necessarily translate to good ergonomic performance.
Recording and organizing qualitative verbal feedback for each trial design was a valuable task that taught me the importance of considering the size, strength, age, height, etc. of all of the possible users. The system must be designed to be workable for everybody.