An innovative haemostat spray powder which can’t cause embolism

Concept development

Challenge
Develop an airless haemostat spray system to eliminate the risk of embolism during surgery.

Approach
Drawing on our extensive experience developing surgical devices, our engineers and scientists created a number of prototypes based on initial concepts.

Outcome
Refined the design based on user feedback to produce a fully functional proof-of-principle device.

We’ve developed countless medical devices over the years, but much of what we do is confidential. So Convesaid is like a concept car for us – a non-confidential way to illustrate how we work, and what device development actually looks like up close.

As well as eliminating the risk of embolism, we also wanted to create a device that was easy to operate, reliable and cheap enough to be disposable.

Haemostat powders are widely used to manage bleeding during surgery – the powder accelerates clotting and can easily be sprayed onto an area of bleeding using an air spray device. However, such devices generally rely on air to deliver the powder particles. The presence of air brings the risk of embolism if the device is placed too close to a vein, and we wanted to come up with a solution that could eliminate this entirely.

As well as eliminating the risk of embolism, we also wanted to create a device that was easy to operate, reliable and cheap enough to be disposable.

These thoughts and ideas led us to develop an airless system for delivering powdered haemostats accurately, safely and cheaply.

How the technology and the Coandă effect works

Our approach

We created initial design concepts and used math modelling to simulate the device’s airflow, and used this work to create the first prototype. Convesaid’s airflow design uses the Coandă principle – the tendency of an airflow to follow an adjacent curved surface – to ensure that only the haemostat powder exits the device, enabling surgical teams to work without worrying about potentially deadly embolism.

Following successful demonstration of our first prototype, we gathered user feedback to further refine the design. The original prototype was connected to an external pump and power source, but feedback suggested a handheld solution would better meet stakeholder needs. We also discovered that people pulled the trigger before switching the device on, so we redesigned the device’s layout to feature a lock-out which prevents the trigger from activating until the device has been switched on.

 
The outcome

Convesaid illustrates how we care about all aspects of development, from the clever new technology and engineering, to the user experience and industrialisation. It’s how we work and how we think.

A small battery-powered pump in the device creates a stream of air. This air picks up powder and drives the particles down the thin nozzle towards the tip. Here the powder particles fly out in a directional spray.

The 'making of' Convesaid

The air follows a smooth curve within the nozzle and is directed back into the device itself. Powder is ejected without any air leaving the opening, which means even if the nozzle were pushed into a vein, it can’t inject any air. This eliminates any potential for air embolism and is what makes Convesaid so intrinsically safe.

It is suitable for use in both laparoscopic and open surgery, and the powder is delivered as a fine, fully controllable jet. Surgical teams can focus on the procedure at hand and not worry about embolism.

 
Media coverage

Business Weekly | Cambridge Network | Cambridge Wireless | Idea Connection | MedGadget | Medical Plastics News | Med-Tech Innovation | The Engineer