Aero

Problem:
Healthcare workers in West Africa became overheated while caring for Ebola patients due to the many layers of Personal Protective Equipment required for safety.

Opportunity:
Create a solution to keep healthcare workers cool, allowing them to remain comfortable for a longer shift.

Solution:
Our team designed Aero, a personal cooling system that can be worn under personal protective equipment. Aero aids evaporative cooling, keeping healthcare workers cooler for longer.

Process:

    I. Research

We began with a deep dive into the experience of doctors who have worn Personal Protective Equipment (PPE) in hot environments. One noted sweat pouring out of her gloves after each clinical round, another said he sweat half a liter each shift, and a third healthcare worker described feeling suffocated every time she donned her PPE.

In the heat, healthcare workers can stay a maximum of 40 minutes to an hour in PPE before needing to remove PPE and rest. At the height of the epidemic, one doctor stated she was caring for 70 patients at a time, and yet the heat made her feel “stupid.” This creates a risk for both her health and the health of the patients.

We put on PPE ourselves and did jumping jacks and pushups, feeling the sweat and humidity mount inside the suits.

 

We researched the standards of PPE necessary for preventing the spread of Ebola, a highly contagious illness spread by fluid contact. Though standards vary, it is a very high level of coverage over all parts of the body, and materials must be fluid-resistant, so sweat quickly accumulates inside. Donning and doffing PPE can take 15-20 minutes, and is a very risky step (high potential for contamination), adding to the stress and length of shifts.

    II. Concept Generation

From our research, we knew our solution needed to be compatible with a variety of PPE, as different clinics had different requirements. It also needed to allow for total mobility, as workers need to be able to lift patients and move flexibly. And, of course, it needed to work to cool people efficiently and effectively.

We went into a sauna armed with ice packs to determine where on the body cooling makes the greatest difference in comfort. The neck made a big impact, and is least likely to be covered when wearing scrubs under PPE, so we focused our efforts there.

Sketch of fan idea, early iteration

Sketch of early harness concept

Sketch of compressed air idea, early iteration

Sketch of harness

We then sketched and prototyped different form factors. We considered various cooling materials, including gels that could be refrigerated. However, given the scarcity of refrigeration in West Africa (where Ebola was most prevalent), we needed a different solution.

Taking inspiration from our natural cooling system, sweat, we decided to deliver dry air flow to the neck. This dehumidified air would cool workers off by aiding the natural process of evaporation. Fans proved the best method for circulating air.

We created a low fidelity prototype to test tube placement and fit across a range of sizes, favoring adjustability and range of motion. We tested desiccants, which dry air out, to dehumidify the air as it circulated.

Our final prototype, Aero, uses pellet desiccant and 4 small fans in a compact form worn as a backpack. All of the straps are adjustable, and it fits under any PPE. For safety, it would be donned first and doffed last. Flexible tubing delivers the dehumidified air to the front and back of the neck, where can effectively cool by helping sweat evaporate. And rechargeable batteries provide 2 hours of comfort, long enough to double the time healthcare workers can work comfortably.

    III. Evaluation

With our most developed prototype of Aero, one group member was able to feel much cooler. After working out in PPE, his neck was no longer sweaty, and subjective heat and discomfort were much reduced. His forehead temperature decreased by 2 degrees when exercising in PPE with Aero.

Collaboration

This project was completed in a team of 4 students as part of MENG 491: Appropriate Technology for the Developing World, taught by Dr. Joe Zinter and Bo Hopkins at Yale University.