for locating cardiac arrest patients at home instantly and deliverying emergency medication under surveillance before an EMS arrives

MAX DU

Regeneron ISEF 2023 Team Canada | CWSF 2022 Platinum Award - Innovation, Youth Can Innovate Award, Challenge Award | National INGENIOUS+ Youth Innovation Regional Award 2022 | CYSF 2022 Young Innovator's Award

Edited by Pranav Khanolkar

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INTRODUCTION

Background
Out-of-hospital cardiac arrest (OHCA) patients have two challenges. First, the patients need immediate rescue since the survival chances are close to zero within 10 minutes. However, the average emergency medical services (EMS) (Rea et al., 2003) response time is 9 minutes or longer in cities in the United States (US) and Canada (Response Times Trends, n.d.) and 22 mins in rural areas. Second, if the patients are home alone, only 4% survive (Sudden Cardiac Arrest Foundation, n.d.) and over half of OHCA patients are unwitnessed. Among the 326,200 OHCA patients per year in the US, 80% happen at home (Graham et al., 2015), and only 10.6% survive (Mozaffarian et al., 2015). With such alarming numbers, these two challenges require solutions.

Currently, community medical bystanders are a worldwide solution by providing patients with CPR /defibrillators before the EMS takeover, but only 38.7% of cardiac arrests are witnessed by bystanders (Mozaffarian, 2015). Moreover, this solution is not applicable in rural, remote areas. In recent years, drones have been used to help save cardiac patients as well. For example, an article by BBC highlights a drone that delivered AED (automated external defibrillators) in OHCA. In addition, a recent study by Maxwell (2021) featured drone networks optimization for quick delivery of AEDs to bystanders. In general, drones provide supplies in cities or rural areas outdoor but leave the rescue to human rescuers. As such, none of them are designed to help indoor patients directly.

Question
How to innovate an indoor drone to help rescue more cardiac arrest patients before EMS or caregivers arrive?

Innovation Goals
In this paper, I present the development of a Pre-hospital Indoor Rescue Drone to witness, intervene, and treat cardiac arrests at home instantly before EMS arrives, saving more lives. The solution to the immediate rescue challenge is to locate and approach patients in seconds, whether they are upstairs or downstairs. When receiving the alert from the wireless SOS button on the patient, the drone receives the GPS coordinates, indicating the location of the patient as the “Home” location, and activates the built-in “Return to Home” function (Barnes, 2021), after which, the drone will fly to the patient with accuracy. The drone can deliver emergency medication to patients under remote EMS surveillance through a pill box containing emergency medical pills or inhalers that prescribed for the patient and an intramuscular needleless autoinjector; for example, the early administration of epinephrine in OHCA (Pugh et al., 2021). The solution to the unwitnessed cardiac arrests is to enable surveillance connection with an EMS team through live video. The first responders can quickly know the patient’s situation and the precise location in the house. Moreover, the drone can open room doors to approach patients if necessary.

METHODS & MATERIALS

Design Criteria & Limitations
Safety: Auto-injection should be limited to the intramuscular needleless injection

Weight: The assembled weight of the drone should be under the 895g payload

Size: The assembly size should fit within the 5x15 cm surface area on the drone

Torque: The gripper torque should be greater than 0.5 lb. to turn a regular round doorknob of a room

System-level Design
The overall drone-system design has four primary subsystems: the drone, medication delivery, door opening, and electronics controls. As shown in Figure 1, the drone system is composed of a flight and a surveillance camera. The medication delivery system is composed of a medicine pillbox, a linear motion system, and an EpiPen-like needleless injector. The door opening system is composed of an arm and gripper connected to a servo and motor. The signals and communications will be sent through the electronic control system to the EMS via two Wixels (Polulu, n.d.); these are small general-purpose programmable modules featuring a 2.4 GHz radio and USB connection. One of the Wixels will be connected to an Arduino microcontroller, and the other Wixel will be connected to a device in the EMS. Next, using pre-programmed software, an EMS team member will be able to see through the drone's camera and authorize the injection of emergency medication with just one push of a button. Currently, the computer coding can control the two motors on the drone from a distance of 15 meters. In the future, I plan to make an interactive app for the EMS staff and using a more powerful radio transmitter.

**Figure 1**: Four primary functions of system design

Mechanial & Electrical Engineering Design
First, three auto-injection designs, four arms, and three grippers were designed. After functionality comparison, low-fidelity testing, and consulting doctors and engineers, the final design included: a pulley auto-injector, linear lift arm, and a two-finger parallel gripper with a cap. Next, detailed engineering designs, which included 3D modelling in SolidWorks, component specifications, and electronic schematics, were completed to verify design feasibility.

Protogyping, Testing, and Coding

Once the design was ready, a prototype was fabricated, tested, and coded. This was an iterative process until the prototype functioned properly. For example, the drone was changed, and the base and gripper were modified. Arduino IDE was used to create motor control sketches and code for the Wixels. Serial ports and serial communication were used to code the Wixels communication between a laptop through a serial monitor. To solve the unbalanced flight issue, the equilibrium point of the assembly for the drone COG (center of gravity) was calculated using the formula: F₁ x L₁ = F₂ x L₂

This equation is called the equilibrium equation (Lyublinskaya, 2017), in which F and L indicate force and length, respectively.

Materials
As shown in Figure 2, the components that were used to build the assembly, which was mounted on a DJI Mavic 3 drone, included: a medication delivery system that comprised mini 9g servos, 380:1 DC Motors (12v), pillbox, needleless injector, pulley, mounting base, and screw; the arm system that comprised: a selfie stick, 1000:1 DC motors (12V), gripper, zip ties; and, the electronic control system that included: the Arduino, L298n motor driver, Wixel, control, batteries, and wiring.

**Figure 2**: Current assembled prototype with labelled components

RESULTS

Currently, the assembled prototype is automated and operational. Through testing and recording, the design is found valid for the following:

Locating and approaching patients instantly: I recorded the time to locate and approach patient at an average of 55 seconds flying upstairs, and landing at a distance ranging from 3 to 6 cm from the person lying on the 2nd floor of a house.
Simulating video surveillance from the drone’s main camera through the DJI FLY application: I successfully tested the drone’s main camera, in which a clear video was broadcast live to a phone connected to a controller placed 15 kilometers away.
Delivering emergency medication with a pillbox and intramuscular auto-injector close to patients: After landing by the patient, the nozzle tip of the injector is placed 3-6 cm away, which is the optimal distance for the auto-injection and close enough for the patient to reach the pillbox. The auto-injection was completed smoothly by running the pre-programmed code on a computer which could wirelessly control the servo at the injector from a distance of 15m through a radio communication system.
Opening room doors through an extendable arm-gripper system: A room door was successfully opened using the arm-gripper system by running a pre-programmed code on a computer which wirelessly controlled the gripper’s motor from 15m.

DISCUSSION

The test results indicate that the drone can start immediate rescue within 1-2 minutes after instantly locating the patient in a residential setting. This suggests that the drone can approach a patient undergoing cardiac arrest sufficiently faster than the EMS. The test results also demonstrate that the drone can start medical intervention before the EMS arrives by successfully delivering pre-prescribed life-saving pills close to the patient, as well as intramuscular auto-injection, which can be activated by the EMS team remotely before the paramedics arrive. Furthermore, simulated video surveillance was achieved through the drone’s main camera by using the DJI FLY application that can cover a 15-kilometer range. Using drone surveillance to provide paramedics and EMS with patient conditions and precise indoor locations can effectively increase patients’ witness coverage 24/7, including those who are home alone, and those are in remote and rural areas.

Future Improvement
Additional improvements to both mechanical and electrical designs are planned.

During the prototyping and testing process, it was observed that the weight and size of the assembly and COG between the assembly and the drone are critical for a stable and balanced flight. As such, from the mechanical-design perspective, there is potential to reduce the weight and size of the assembly, through further exploring substitute parts and materials, and simplifying the mechanism designs.

In electrical design, future work will aim to accomplish real-time live video surveillance, which solves the wireless connection between the cardiac patient and EMS team for more efficient lifesaving. Such future work can include methods to improve communication and activation of the drones by the patients. In this, the patient should be able to activate the drone by using a series of Wi-Fi User Diagram Protocol (UDP. Future work could also aim towards the development of an application that allows the EMS team to control the auto-injector with the press of a button by using an xBee.

Application Extension
The design can be refined to benefit other patients at high risk of needing emergency medications and surveillance anytime at home, such as diabetes patients experiencing diabetic coma, high-risk allergy patients, and angina patients.

CONCLUSION

The innovative pre-hospital indoor rescue drone solves the two challenges that cardiac arrest patients face: 1. starting rescue faster and 2. witnessing more patients, including those patients that are home alone. Anyone at risk of cardiac arrests can use this innovation as an efficient rescue helper standby 24/7 at home in the first critical minutes before EMS arrives.

As the first indoor pre-hospital rescue drone designed to help save cardiac arrest patients at home, its approach to emergency medication delivery under surveillance is unique. In addition, its approach to door opening is novel. The innovation contribution is significant, which unlocks a novel solution to save people’s lives, and expands the availability and capability of unmanned aircraft for indoor emergency rescue.

ACKNOWLEDGEMENTS

I would like to thank Alvin Qi, Dr. Michael Tymianski, Dr. Jane Cho, Mark Piitz for professional medical advice; thanks to David Storrier and Kun Gong for their guidance in mechanical engineering, electrical engineering and coding; thanks to Robotics Team FTC 10015, Queen Elizabeth High School, the University of Calgary the Stroke Robotics and Recovery Lab, and Schulich UAV for providing 3D printing and fabrication support.

BIBLIOGRAPHY

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A Novel Pre-Hospital Indoor Rescue Drone