Revolutionizing healthcare: Navigating the trajectory of unmanned aerial vehicles from history to horizon

Introduction

An unmanned aerial vehicle (UAV) is described as a powered flying vehicle that lacks a human operator, relies on aerodynamic forces for lift, can operate autonomously or under remote piloting, and is capable of carrying both lethal and nonlethal payloads; details are given in Table 1.^1,2 They come in a wide range of sizes, from small handheld models to large aircraft-like devices. The utilization of UAVs in warfare began during the 19th century, starting with the navy in Italy using a balloon carrier.³ Details are given in Table 2. Over time, significant advancements in aerospace engineering have improved the structure and functionalities of UAVs.

Table 1.

Working principles of drones.

Power source	Drones are powered by batteries or fuel cells, depending on the model. Most consumer-grade drones use rechargeable lithium-polymer batteries.
Propellers	Drones have multiple propellers that provide lift and control. Quadcopters, for example, have four propellers, while hexacopters have six.
Flight control	Drones have an onboard flight controller that processes inputs from sensors and the remote control or an autonomous flight system.
Sensors	Drones are equipped with various sensors, including GPS, accelerometers, gyroscopes, and altimeters. These sensors help the drone maintain stability and navigate accurately.
Remote control or autonomous system	Drones can be controlled by a human operator using a remote control or be programmed to fly autonomously along a predefined route.
Communication	Drones communicate with the remote control or ground station through radio signals, enabling the operator to send commands and receive telemetry data (such as altitude, battery level, and GPS coordinates).
Camera and payload	Many drones have built-in cameras that capture images and videos. Advanced drones can carry additional payloads, such as thermal cameras, LiDAR sensors, or even packages for delivery purposes.

Abbreviations: LiDAR = GPS = Global Positioning System; Light Detection and Ranging.

Table 2.

Evolution of drones.

Early concepts (1849–1917)	The concept of unmanned flying machines can be traced back to the mid-19th century. In 1849, Austrian soldiers used unmanned balloons loaded with explosives for military purposes. In the early 20th century, various inventors experimented with radio-controlled aircraft, but the technology was still in its infancy.
Aerial Target (1916–1917)	During World War I, the British Royal Flying Corps developed the “Aerial Target,” a radio-controlled aircraft used as a flying bomb to counter the threat of Zeppelin airships. The Aerial Target was not a true drone as it lacked autonomy, but it marked a significant step in the development of unmanned flying machines.
Radioplane OQ-2 (1939–1940)	During World War II, actor and inventor Reginald Denny created the Radioplane OQ-2, one of the first mass-produced remote-controlled aircraft. It was initially used as a target for antiaircraft gunnery training but later adapted for reconnaissance purposes.
The Birth of UAVs (1950s-1960s)	The term “Unmanned Aerial Vehicle” (UAV) was coined in the 1950s when the United States military started developing drone aircraft for reconnaissance and surveillance. During this period, the U.S. produced several UAVs, including the Ryan Firebee series.
Predator and Global Hawk (1990s)	In the 1990s, the U.S. military made significant advancements in drone technology with the introduction of the MQ-1 Predator, which became the first drone capable of carrying and firing missiles. Additionally, the RQ-4 Global Hawk, an advanced surveillance drone, was introduced during this time.
Consumer and commercial drones (2000s)	In the early 2000s, advancements in miniaturization, battery technology, and GPS led to the emergence of consumer-grade drones. Companies such as DJI played a pivotal role in making drones accessible to the general public. These drones were mainly used for photography and recreational purposes.
Widening applications (2010s)	Throughout the 2010s, the range of drone applications expanded rapidly. Drones found applications in industries such as agriculture, filmmaking, construction, environmental monitoring, search and rescue, and more.
Drone regulations (2010s)	As drone usage increased, so did concerns over safety and privacy. Governments around the world began introducing regulations to govern drone operations and ensure safe integration into airspace.
Future prospects (2020s and beyond)	Drone technology continued to advance, with research on going into swarming capabilities, AI-driven autonomous flight, longer endurance, and beyond-visual-line-of-sigh operations. Drones are expected to play an essential role in various industries and continue to evolve in the years to come.

Abbreviation: AI = artificial intelligence.

Originally confined to military applications, their usage has now expanded rapidly to include various modern uses such as air-quality sampling, monitoring harmful gases, industrial hygiene, safety management, studying road traffic accidents, tracking flora and fauna, and examining landscape ecology, such as studying malaria in rubber plantations.⁴

However, the application of UAVs in public health remains less explored than their implementation in other fields. In this article, we explore the potential of utilizing UAVs or drones in different areas of public health. Additionally, we discuss the advantages and potential obstacles that need to be addressed for successful integration of UAVs in public health initiatives at international and national levels.

Present applications of drones

Drones have demonstrated promising applications in the healthcare sector, particularly in improving access to medical supplies and providing rapid emergency response. In the Indian context, tribal and hilly areas are such areas where drones can become very useful for supplying medicines. Drones can transport essential medical supplies, such as medicines, vaccines, blood products, and diagnostic test samples, to remote or hard-to-reach areas. This capability is particularly valuable in regions with inadequate infrastructure or during emergency situations such as natural disasters. For example, Zipline, a drone delivery service, partnered with the Rwandan government to deliver blood supplies to remote hospitals.⁵ A study published in 2016 reported on the impact of drone deliveries on blood transfusion in Rwanda.⁶ The study highlighted how drone deliveries significantly reduced the time taken to transport blood products to rural health facilities, improving access to critical medical supplies and potentially saving lives.⁶ A research project in Ghana explored the use of drones to transport diagnostic samples from remote clinics to central laboratories for testing.⁷ The study assessed the feasibility, accuracy, and cost-effectiveness of using drones to transport samples, potentially improving access to timely and accurate diagnostic services in resource-limited settings.

In 2019, the state of Telangana in India conducted a pilot project in collaboration with the World Economic Forum and HealthNet Global Limited. The project aimed to test the feasibility of using drones for delivering vaccines to remote and hard-to-reach areas. Drones successfully transported vaccines from a primary health center to a remote village, demonstrating the potential of this technology to improve vaccine access in underserved regions.⁸

Drones have been used to transport donor organs for transplantation quickly and efficiently. This can help overcome transportation challenges, reduce organ transportation times, and improve the success rate of organ transplants. In 2019, researchers from the University Of Maryland School Of Medicine conducted a study to evaluate the feasibility and safety of using drones to transport donor organs for transplantation. They successfully transported a kidney via a drone over a distance of approximately 2.8 miles. The study demonstrated the potential of using drones to speed-up organ transport and improve access to donor organs.⁹ Drones equipped with medical equipment, defibrillators, or first aid supplies can reach accident scenes or medical emergencies faster than traditional ambulances, especially in congested urban areas.⁴

A research project conducted in Sweden explored the use of drones for emergency medical response in urban environments. The study, published in the Scandinavian Journal of Trauma, Resuscitation, and Emergency Medicine in 2017, investigated how drones equipped with automated external defibrillators (AEDs) could be deployed to assist cardiac-arrest patients before the arrival of emergency medical services. The findings suggested that drone delivery of AEDs could potentially reduce response times and improve survival rates in cardiac arrest cases.

The state of Uttarakhand in India has been exploring the use of drones for delivering medical supplies, including blood, to remote and inaccessible areas. The government partnered with private companies to conduct trials for transporting blood samples and medical supplies between hospitals, thereby reducing the time taken for critical supplies to reach patients in need.¹⁰ Drones can be used as a platform for telemedicine, facilitating communication between remote patients and healthcare professionals. They can deliver medical data, facilitate video consultations, and provide real-time monitoring in remote locations. In 2020, the Andaman and Nicobar Islands administration initiated a project to provide telemedicine services to remote island communities using drones. The project aimed to use drones to deliver telemedicine kits to health centers on different islands, enabling virtual medical consultations and improved healthcare access.¹¹

Drones equipped with sensors and cameras can assist in monitoring disease outbreaks, environmental factors affecting health, and the movement of disease-carrying vectors (e.g., mosquitoes). This information can help authorities respond quickly to potential health threats. In 2018, researchers from the University of São Paulo conducted a study using drones to capture mosquito larvae in urban areas to monitor and control the spread of mosquito-borne diseases such as dengue and Zika.¹² The study demonstrated the effectiveness of drones in identifying potential breeding sites and assessing the risk of disease transmission in hard-to-reach areas.

In collaboration with the Indian Council of Medical Research, a project was initiated in Karnataka to study the potential of drones in monitoring and controlling malaria.¹³ Drones were used to capture images and videos of water bodies and potential breeding sites of malaria-carrying mosquitoes, aiding in disease surveillance efforts.¹¹

Drones have proven to be valuable tools in delivering humanitarian aid during disasters and crises. They can assess damage, locate survivors, and deliver critical supplies to affected populations. They can be used to broadcast health awareness messages, distribute educational materials, and spray insecticides for vector control in disease-prone areas. Drones can act as a bridge to provide medical services to remote communities where healthcare facilities are scarce or non-existent such as tribal areas in India.

Challenges

While drones offer promising solutions for various healthcare challenges in India, their adoption in the healthcare system also faces several significant challenges.¹⁴ Some of the key challenges are as follows:

• 1)One of the primary challenges is navigating complex and evolving regulations governing drone usage in India. Strict airspace regulations, security concerns, and privacy issues can hinder the seamless integration of drones into the healthcare system.
• 2)Many remote and underserved areas in India lack adequate infrastructure to support drone operations. The absence of suitable landing and charging facilities can impede the deployment of drones for medical supply delivery and emergency response.
• 3)Ensuring the safety of drone operations in populated areas is a critical concern. The risk of collisions with other aircrafts, buildings, or people demands robust safety protocols and reliable collision-avoidance systems.
• 4)India's diverse weather conditions, including monsoons and extreme heat, pose challenges for drone flights. Rain and wind can affect flight stability and range, making it difficult to maintain consistent drone operations throughout the year.
• 5)Most consumer-grade drones have limited payload capacity, which can be a constraint for transporting larger medical supplies or equipment.
• 6)Reliable and stable communication networks are essential for controlling and monitoring drones. In remote areas with limited network coverage, maintaining real-time communication with the drone can be challenging.
• 7)The initial investment and operational costs of implementing drone technology can be significant. For resource-constrained healthcare facilities, financing drone operations may be a barrier.
• 8)Widespread adoption of drones in the healthcare system may require gaining public trust and acceptance. Concerns about privacy, noise pollution, and potential misuse of drone technology may impact community support for drone initiatives.
• 9)Operating drones in the healthcare context requires trained personnel who understand drone operations, flight planning, maintenance, and troubleshooting. Ensuring an adequate number of skilled operators is essential.
• 10)Deploying drones for healthcare services raises ethical questions related to data privacy, informed consent, and potential impacts on the local workforce.

Future research avenues

The future of drone technology holds immense promise, and researchers are actively exploring various avenues to further advance its capabilities and applications. Some of the key research avenues with drone technology include advancements in artificial intelligence and machine learning, which are driving research into autonomous drone navigation. Researchers are working on developing algorithms that enable drones to navigate complex environments, avoid obstacles, and make real-time decisions without human intervention.¹⁵ Research is also being conducted to enable drones to work collaboratively in swarms. Swarming drones can perform complex tasks, such as mapping large areas, search and rescue operations, and surveillance, more efficiently by sharing information and coordinating their actions.¹⁶

Current drone regulations often require operators to maintain visual contact with their drones. Researchers are working on technologies and protocols to enable beyond-visual-line-of-sight operations, allowing drones to fly beyond the operator's line of sight, which would open up new possibilities for applications such as long-range delivery and infrastructure inspection.¹⁷ Improving the energy efficiency of drones and extending their flight endurance are important research areas. Advances in battery technology, solar-powered drones, and energy-efficient propulsion systems can lead to longer flight times and increased mission capabilities.¹⁸

Researchers are also exploring environmentally friendly drone materials and technologies to reduce the ecological footprint of drone operations. Sustainable manufacturing practices, biodegradable materials, and noise-reduction technologies are areas of interest.

Modern research is targeting to enhance payload flexibility, which allows drones to carry a wider range of sensors and equipment, enabling diverse applications in fields such as agriculture, environmental monitoring, and disaster response. Researchers are also working on the integration of 5G connectivity, and edge computing can improve communication and data-processing capabilities, enabling real-time transmission of high-resolution data and supporting more sophisticated drone applications.¹⁹ Research is on-going to explore the use of drones for medical emergencies, organ transportation, telemedicine, and disease surveillance, further advancing the potential of drones in the healthcare sector. Apart from this, Urban Air Mobility research focuses on developing systems for safe and efficient drone operations in urban environments.²⁰ This includes the integration of drones into existing air traffic management systems and the development of vertiports for drone take-off and landing.²¹ Additionally, ensuring the privacy and security of data transmitted and collected by drones is crucial. Researchers are investigating encryption techniques (blockchain) and secure communication protocols to safeguard sensitive information.²²

Conclusion

As drones become more ubiquitous, understanding and enhancing human–drone interaction is crucial for user acceptance and safety. Research in this area explores intuitive and user-friendly interfaces for drone control and communication. Overall, on-going research and innovation in drone technology are expected to result in more efficient, safe, and versatile drone systems, unlocking new opportunities across various industries and improving the quality of life for people around the world.

Disclosure of competing interest

The authors have none to declare.