Robot Performs Contact-Free Vital Sign Assessments, Enhancing Safety in Healthcare

During the coronavirus pandemic, one of the riskiest parts of a healthcare worker’s job is assessing people who have symptoms of COVID-19. Researchers are reducing that risk by using robots to remotely measure patients’ vital signs. The robots, which are controlled by a handheld device, can also carry a tablet that allows doctors to ask patients about their symptoms without being in the same room.

Using four cameras mounted on a doglike robot, the researchers have shown that they can measure skin temperature, breathing rate, pulse rate, and blood oxygen saturation in healthy patients from a distance of 2 meters.

Existing computer vision technologies were used that can measure temperature, breathing rate, pulse, and blood oxygen saturation — they were then made mobile. To achieve that, they used a robot known as Spot that can walk on four legs, similar to a dog. Healthcare workers can maneuver the robot to wherever patients are sitting, using a handheld controller. The researchers mounted four different cameras onto the robot: an infrared camera plus three monochrome cameras that filter different wavelengths of light.

The researchers developed algorithms that allow them to use the infrared camera to measure both elevated skin temperature and breathing rate. For body temperature, the camera measures skin temperature on the face and the algorithm correlates that temperature with core body temperature. The algorithm also takes into account the ambient temperature and the distance between the camera and the patient, so that measurements can be taken from different distances, under different weather conditions, and still be accurate.

Measurements from the infrared camera can also be used to calculate the patient’s breathing rate. As the patient breathes in and out, wearing a mask, their breath changes the temperature of the mask. Measuring this temperature change allows the researchers to calculate how rapidly the patient is breathing.

The three monochrome cameras each filter a different wavelength of light — 670, 810, and 880 nanometers. These wavelengths allow the researchers to measure the slight color changes that result when hemoglobin in blood cells binds to oxygen and flows through blood vessels. The researchers’ algorithm uses these measurements to calculate both pulse rate and blood oxygen saturation.

The researchers performed the measurements on healthy volunteers and they are now making plans to test the approach, in a hospital emergency department, in people who are showing symptoms of COVID-19. In the longer term, the team envisions that the robots could be deployed in patients’ hospital rooms. This would allow the robots to continuously monitor patients and also allow doctors to check on them, via tablet, without having to enter the room.