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Covid-Sniffing Canines Are Correct, However Extensive Use Faces Hurdles

Dog noses are great Covid-19 detectors, according to numerous laboratory studies, and Covid detection dogs have already started working at airports in other countries and at some events in the US, like a Miami Heat basketball game.

However, some public health and sniffer dog training experts say more information and planning is needed to ensure they are accurate in real-life situations.

“There are no national standards” for scented dogs, said Cynthia M. Otto, director of the Penn Vet Working Dog Center at the University of Pennsylvania School of Veterinary Medicine and one of the authors of a new article on the use of scented dogs in Covid detection.

And while private groups certify drug sniffing and bomb and rescue dogs, there are no similar medical detection programs in place in the journal Disaster Medicine and Public Health Preparedness, according to the new paper.

Lois Privor-Dumm, a public health researcher at Johns Hopkins University and lead author of the article, said there is no question that dogs have great potential in medical fields. But she wants to investigate how they could be used on a large scale, for example by the government.

“What are all the ethical considerations? What are the regulatory considerations? How practical is that? ”She asked. Not only the quality of detection, but logistics and cost would be central to any widespread application, as with any public health intervention.

Quality control is a first step and a big one. Medical odor detection is more complicated than detecting drugs or bombs, said Dr. Otto. A dog working to detect drugs or explosives in an airport has a consistent context and a fairly simple target odor. With Covid detection, researchers know that dogs can differentiate between sweat and urine from an infected person. But they don’t know what chemicals the dog is identifying.

Because human smells vary, medical sniffer dogs must be trained on many different people. “We have all races and ages and diets and all these things that make people smell,” said Dr. Otto.

The symptoms of many illnesses are similar to those of Covid, and dogs smelling odors related to fever or pneumonia would be ineffective. Therefore, according to Dr. Otto “include many people who are negative but might have a cough or a fever or other things”. Obviously, if the dogs mistake flu for Covid, that would be a critical mistake.

Dogs can also be trained on sweat, saliva, or urine. In the United Arab Emirates, the dogs worked with urine samples. In Miami they just walked past a number of people.

Any positive cases of Covid infection that the dogs detect are usually confirmed using today’s gold standard to confirm the presence of the coronavirus, a PCR test. However, a review of the research published last week concluded that dogs fared better than the test.

But these are experimental results. Dogs are good at remotely detecting explosives and other substances, but so far, Dr. Otto that she is not aware of any published research showing the accuracy of dogs who sniff people in a line instead of urine or sweat.

If the government were to officially conduct or approve dogs for Covid detection, some standards would need to be set for how dogs should be trained and their performance assessed. Dr. Otto is on a committee of the National Institute of Standards and Technology that is now meeting to develop standards for scent detection dogs in a variety of situations, including detecting Covid.

She said even if the standards were clearly set, finding enough dogs to do widespread odor detection was another hurdle. Trained dogs are not easy to come by. “We have a shortage of bomb detection dogs in this country. We’ve been dealing with it for years, ”she said.

Dogs can be retrained from one smell to another, but that can be tricky. “Some countries take their bomb trained dogs and train them on Covid. But you know, all you have to do is think of an airport, if you have a dog that sniffs both covid and bombs and it alerts you, then what do you have? “

Well-trained dogs are also costly and require paid, well-trained human handlers. According to the report, dogs can cost $ 10,000 and odor training can cost $ 16,000 per dog. For example, the Transportation Security Administration has a $ 12 million explosive detection dog and handler training facility in San Antonio and estimates the cost of training dogs and handlers at $ 33,000 for explosives detection and $ 46,000 for passenger control.

All of these questions will determine how dogs will be used in the future. Your ability is there. “I think they absolutely can,” said Dr. Otto. “This is how we implement them.”

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Pulse Oximeters Could Be Much less Correct for Black Individuals. Ought to You Use One?

Home pulse oximeters were the personal tech device of 2020 and a calming way for patients to monitor their health at home during Covid-19.

However, a new study found that even in a hospital, pulse oximetry machines can sometimes be inaccurate, especially with black patients. The finding has raised questions about whether people with darker skin should rely on home surveillance.

Doctors say the devices that measure blood oxygen levels are still extremely useful in detecting deterioration in health in all Covid-19 patients, including those with darker skin, before they become seriously ill. If the device is wrong, it is likely that the reading is only a few percentage points different. It is important that all patients, especially those with darker skin, watch out for a downward trend in oxygen levels rather than fixating on a specific number.

“I think having information from a pulse oximeter is better than not having no information,” said Dr. Michael W. Sjoding, Assistant Professor of Internal Medicine in the University of Michigan Medical School and lead author of the new report that appeared in the New England Journal of Medicine. “I would also say that one has to understand that a pulse oximeter is an imperfect device.”

A pulse oximeter looks like a chip clip. When you insert your finger into a pulse oximeter, it emits different wavelengths of light through your skin. The amount of light that is absorbed reflects how much oxygen is in your blood. It has long been known that dark nail polish, cold skin and darker skin pigment can affect the reading. However, the new study suggests that the problem is more common in black patients than most doctors thought.

The analysis, which was based on 1,333 white patients and 276 black patients hospitalized at the University of Michigan earlier this year, used a hospital-based pulse oximeter and compared it to the gold standard test for measuring oxygen saturation known as arterial blood gas Exam. The study found that pulse oximetry overestimated oxygen levels in white patients 3.6 percent of the time, but was incorrect in nearly 12 percent of the cases in black patients. Usually the pulse oximetry reading was overstated by a few percentage points.

Updated

Apr. 23, 2020 at 8:46 am ET

Researchers suspect the inaccurate readings may be due to the way the light is absorbed by darker skin pigments.

A normal reading on a pulse oximeter is usually between 96 and 100. Because patients with Covid-19 can quietly develop low oxygen levels without realizing it, patients are advised to monitor their oxygen levels at home. If the oxygen level drops to 93 or 92, patients are advised to check with their doctor. However, as the Michigan study shows, when a pulse oximeter sometimes overestimates oxygen saturation levels, there is concern that if the monitor reads 94 or 95 incorrectly, a patient with dark skin and self-monitoring at home may delay care, if the patient’s actual oxygen level can be 92 or 93.

According to Dr. Sjoding’s solution is for patients to know their baseline values ​​on their home device and watch out for downward trends. If you’re sick with Covid-19 at home and your normal reading drops by four points or more, this is a good reason to call your doctor.

While seeking care is important, you don’t need to panic. Oxygen saturation levels in their low 90s are an issue for people with Covid-19, but can be treated with assistive oxygen placed on the stomach to increase the flow of oxygen to your lungs and possibly other therapies.

“I would say if you happen to have a pulse oximeter at home, make sure you know what your normal level is so you know what a change is for you,” said Dr. Sjoding. “If your home pulse oximeter reads 98 when you purchase it and you are healthy and you are 94 years old and unwell, that is a pretty strong sign that you are sick and should see a doctor. ”

While the study focused on a group of patients who reported themselves as African American, it is reasonable to assume that the risk of error would be similar in other darker-skinned patients. The results are particularly worrying given that the pandemic is disproportionately affecting Black and Hispanic Americans. Studies have found that African Americans were hospitalized more often, suggesting delays in accessing medical care.

While the new data on the accuracy of the pulse oximeter is important in helping doctors better interpret oxygen levels in color patients, Dr. Sjoding states that the results should not deter consumers from using the devices at home as long as they know the limits of the information a pulse oximeter can provide.

“My study is more about the emergency doctor who has to decide whether a patient should be hospitalized or taken to the intensive care unit,” said Dr. Sjoding. “For people at home, the pulse oximeter is still a worthwhile device and there is still valuable information to be found.”

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