David Warmflash, MD

Nearly 90,000 patients in the United States are waiting for a lifesaving kidney transplant, yet only about 25,000 kidney transplants were performed last year. Thousands die each year while they wait. Others are not suitable transplant candidates.

Half a million people are on dialysis, the only transplant alternative for those with kidney failure. This greatly impacts their work, relationships, and quality of life.

Researchers from The Kidney Project hope to solve this public health crisis with a futuristic approach: an implantable bioartificial kidney. That hope is slowly approaching reality. Early prototypes have been tested successfully in preclinical research and clinical trials could lie ahead.

This news organization spoke with two researchers who came up with the idea: nephrologist William Dr. Fissell, MD, of Vanderbilt University in Nashville, Tenn., and Shuvo Dr. Roy, PhD, a biomedical engineer at the University of California, San Francisco. This interview has been edited for length and clarity.
 

Question: Could you summarize the clinical problem with chronic kidney disease?

Dr. Fissell: Dialysis treatment, although lifesaving, is incomplete. Healthy kidneys do a variety of things that dialysis cannot provide. Transplant is absolutely the best remedy, but donor organs are vanishingly scarce. Our goal has been to develop a mass-produced, universal donor kidney to render the issue of scarcity – scarcity of time, scarcity of resources, scarcity of money, scarcity of donor organs – irrelevant.

Do you envision your implantable, bioartificial kidney as a bridge to transplantation? Or can it be even more, like a bionic organ, as good as a natural organ and thus better than a transplant?

Dr. Roy: We see it initially as a bridge to transplantation or as a better option than dialysis for those who will never get a transplant. We’re not trying to create the “Six Million Dollar Man.” The goal is to keep patients off dialysis – to deliver some, but probably not all, of the benefits of a kidney transplant in a mass-produced device that anybody can receive.

Dr. Fissell: The technology is aimed at people in stage 5 renal disease, the final stage, when kidneys are failing, and dialysis is the only option to maintain life. We want to make dialysis a thing of the past, put dialysis machines in museums like the iron lung, which was so vital to keeping people alive several decades ago but is mostly obsolete today.

How did you two come up with this idea? How did you get started working together?

Dr. Roy: I had just begun my career as a research biomedical engineer when I met Dr. William Fissell, who was then contemplating a career in nephrology. He opened my eyes to the problems faced by patients affected by kidney failure. Through our discussions, we quickly realized that while we could improve dialysis machines, patients needed and deserved something better – a treatment that improves their health while also allowing them to keep a job, travel readily, and consume food and drink without restrictions. Basically, something that works more like a kidney transplant.

How does the artificial kidney differ from dialysis?

Dr. Fissell: Dialysis is an intermittent stop-and-start treatment. The artificial kidney is continuous, around-the-clock treatment. There are a couple of advantages to that. The first is that you can maintain your body’s fluid balance. In dialysis, you get rid of 2-3 days’ worth of fluid in a couple of hours, and that’s very stressful to the heart and maybe to the brain as well. Second advantage is that patients will be able to eat a normal diet. Some waste products that are byproducts of our nutritional intake are slow to leave the body. So in dialysis, we restrict the diet severely and add medicines to soak up extra phosphorus. With a continuous treatment, you can balance excretion and intake.

The other aspect is that dialysis requires an immense amount of disposables. Hundreds of liters of water per patient per treatment, hundreds of thousands of dialysis cartridges and IV bags every year. The artificial kidney doesn’t need a water supply, disposable sorbent, or cartridges.
 

How does the artificial kidney work?

Dr. Fissell: Just like a healthy kidney. We have a unit that filters the blood so that red blood cells, white blood cells, platelets, antibodies, albumin – all the good stuff that your body worked hard to synthesize – stays in the blood, but a watery soup of toxins and waste is separated out. In a second unit, called the bioreactor, kidney cells concentrate those wastes and toxins into urine.

Dr. Roy: We used a technology called silicon micro-machining to invent an entirely new membrane that mimics a healthy kidney’s filters. It filters the blood just using the patient’s heart as a pump. No electric motors, no batteries, no wires. This lets us have something that’s completely implanted.

We also developed a cell culture of kidney cells that function in an artificial kidney. Normally, cells in a dish don’t fully adopt the features of a cell in the body. We looked at the literature around 3-D printing of organs. We learned that, in addition to fluid flow, stiff scaffolds, like cell culture dishes, trigger specific signals that keep the cells from functioning. We overcame that by looking at the physical microenvironment of the cells –  not the hormones and proteins, but instead the fundamentals of the laboratory environment. For example, most organs are soft, yet plastic lab dishes are hard. By using tools that replicated the softness and fluid flow of a healthy kidney, remarkably, these cells functioned better than on a plastic dish.
 

Would patients need immunosuppressive or anticoagulation medication?

Dr. Fissell: They wouldn’t need either. The structure and chemistry of the device prevents blood from clotting. And the membranes in the device are a physical barrier between the host immune system and the donor cells, so the body won’t reject the device.

What is the state of the technology now?

Dr. Fissell: We have shown the function of the filters and the function of the cells, both separately and together, in preclinical in vivo testing. What we now need to do is construct clinical-grade devices and complete sterility and biocompatibility testing to initiate a human trial. That’s going to take between $12 million and $15 million in device manufacturing.

So it’s more a matter of money than time until the first clinical trials?

Dr. Roy: Yes, exactly. We don’t like to say that a clinical trial will start by such-and-such year. From the very start of the project, we have been resource limited.

A version of this article first appeared on Medscape.com.

Nearly 90,000 patients in the United States are waiting for a lifesaving kidney transplant, yet only about 25,000 kidney transplants were performed last year. Thousands die each year while they wait. Others are not suitable transplant candidates.

Half a million people are on dialysis, the only transplant alternative for those with kidney failure. This greatly impacts their work, relationships, and quality of life.

Researchers from The Kidney Project hope to solve this public health crisis with a futuristic approach: an implantable bioartificial kidney. That hope is slowly approaching reality. Early prototypes have been tested successfully in preclinical research and clinical trials could lie ahead.

This news organization spoke with two researchers who came up with the idea: nephrologist William Dr. Fissell, MD, of Vanderbilt University in Nashville, Tenn., and Shuvo Dr. Roy, PhD, a biomedical engineer at the University of California, San Francisco. This interview has been edited for length and clarity.
 

Question: Could you summarize the clinical problem with chronic kidney disease?

Dr. Fissell: Dialysis treatment, although lifesaving, is incomplete. Healthy kidneys do a variety of things that dialysis cannot provide. Transplant is absolutely the best remedy, but donor organs are vanishingly scarce. Our goal has been to develop a mass-produced, universal donor kidney to render the issue of scarcity – scarcity of time, scarcity of resources, scarcity of money, scarcity of donor organs – irrelevant.

Do you envision your implantable, bioartificial kidney as a bridge to transplantation? Or can it be even more, like a bionic organ, as good as a natural organ and thus better than a transplant?

Dr. Roy: We see it initially as a bridge to transplantation or as a better option than dialysis for those who will never get a transplant. We’re not trying to create the “Six Million Dollar Man.” The goal is to keep patients off dialysis – to deliver some, but probably not all, of the benefits of a kidney transplant in a mass-produced device that anybody can receive.

Dr. Fissell: The technology is aimed at people in stage 5 renal disease, the final stage, when kidneys are failing, and dialysis is the only option to maintain life. We want to make dialysis a thing of the past, put dialysis machines in museums like the iron lung, which was so vital to keeping people alive several decades ago but is mostly obsolete today.

How did you two come up with this idea? How did you get started working together?

Dr. Roy: I had just begun my career as a research biomedical engineer when I met Dr. William Fissell, who was then contemplating a career in nephrology. He opened my eyes to the problems faced by patients affected by kidney failure. Through our discussions, we quickly realized that while we could improve dialysis machines, patients needed and deserved something better – a treatment that improves their health while also allowing them to keep a job, travel readily, and consume food and drink without restrictions. Basically, something that works more like a kidney transplant.

How does the artificial kidney differ from dialysis?

Dr. Fissell: Dialysis is an intermittent stop-and-start treatment. The artificial kidney is continuous, around-the-clock treatment. There are a couple of advantages to that. The first is that you can maintain your body’s fluid balance. In dialysis, you get rid of 2-3 days’ worth of fluid in a couple of hours, and that’s very stressful to the heart and maybe to the brain as well. Second advantage is that patients will be able to eat a normal diet. Some waste products that are byproducts of our nutritional intake are slow to leave the body. So in dialysis, we restrict the diet severely and add medicines to soak up extra phosphorus. With a continuous treatment, you can balance excretion and intake.

The other aspect is that dialysis requires an immense amount of disposables. Hundreds of liters of water per patient per treatment, hundreds of thousands of dialysis cartridges and IV bags every year. The artificial kidney doesn’t need a water supply, disposable sorbent, or cartridges.
 

How does the artificial kidney work?

Dr. Fissell: Just like a healthy kidney. We have a unit that filters the blood so that red blood cells, white blood cells, platelets, antibodies, albumin – all the good stuff that your body worked hard to synthesize – stays in the blood, but a watery soup of toxins and waste is separated out. In a second unit, called the bioreactor, kidney cells concentrate those wastes and toxins into urine.

Dr. Roy: We used a technology called silicon micro-machining to invent an entirely new membrane that mimics a healthy kidney’s filters. It filters the blood just using the patient’s heart as a pump. No electric motors, no batteries, no wires. This lets us have something that’s completely implanted.

We also developed a cell culture of kidney cells that function in an artificial kidney. Normally, cells in a dish don’t fully adopt the features of a cell in the body. We looked at the literature around 3-D printing of organs. We learned that, in addition to fluid flow, stiff scaffolds, like cell culture dishes, trigger specific signals that keep the cells from functioning. We overcame that by looking at the physical microenvironment of the cells –  not the hormones and proteins, but instead the fundamentals of the laboratory environment. For example, most organs are soft, yet plastic lab dishes are hard. By using tools that replicated the softness and fluid flow of a healthy kidney, remarkably, these cells functioned better than on a plastic dish.
 

Would patients need immunosuppressive or anticoagulation medication?

Dr. Fissell: They wouldn’t need either. The structure and chemistry of the device prevents blood from clotting. And the membranes in the device are a physical barrier between the host immune system and the donor cells, so the body won’t reject the device.

What is the state of the technology now?

Dr. Fissell: We have shown the function of the filters and the function of the cells, both separately and together, in preclinical in vivo testing. What we now need to do is construct clinical-grade devices and complete sterility and biocompatibility testing to initiate a human trial. That’s going to take between $12 million and $15 million in device manufacturing.

So it’s more a matter of money than time until the first clinical trials?

Dr. Roy: Yes, exactly. We don’t like to say that a clinical trial will start by such-and-such year. From the very start of the project, we have been resource limited.

A version of this article first appeared on Medscape.com.

Nearly 90,000 patients in the United States are waiting for a lifesaving kidney transplant, yet only about 25,000 kidney transplants were performed last year. Thousands die each year while they wait. Others are not suitable transplant candidates.

Half a million people are on dialysis, the only transplant alternative for those with kidney failure. This greatly impacts their work, relationships, and quality of life.

Researchers from The Kidney Project hope to solve this public health crisis with a futuristic approach: an implantable bioartificial kidney. That hope is slowly approaching reality. Early prototypes have been tested successfully in preclinical research and clinical trials could lie ahead.

This news organization spoke with two researchers who came up with the idea: nephrologist William Dr. Fissell, MD, of Vanderbilt University in Nashville, Tenn., and Shuvo Dr. Roy, PhD, a biomedical engineer at the University of California, San Francisco. This interview has been edited for length and clarity.
 

Question: Could you summarize the clinical problem with chronic kidney disease?

Dr. Fissell: Dialysis treatment, although lifesaving, is incomplete. Healthy kidneys do a variety of things that dialysis cannot provide. Transplant is absolutely the best remedy, but donor organs are vanishingly scarce. Our goal has been to develop a mass-produced, universal donor kidney to render the issue of scarcity – scarcity of time, scarcity of resources, scarcity of money, scarcity of donor organs – irrelevant.

Do you envision your implantable, bioartificial kidney as a bridge to transplantation? Or can it be even more, like a bionic organ, as good as a natural organ and thus better than a transplant?

Dr. Roy: We see it initially as a bridge to transplantation or as a better option than dialysis for those who will never get a transplant. We’re not trying to create the “Six Million Dollar Man.” The goal is to keep patients off dialysis – to deliver some, but probably not all, of the benefits of a kidney transplant in a mass-produced device that anybody can receive.

Dr. Fissell: The technology is aimed at people in stage 5 renal disease, the final stage, when kidneys are failing, and dialysis is the only option to maintain life. We want to make dialysis a thing of the past, put dialysis machines in museums like the iron lung, which was so vital to keeping people alive several decades ago but is mostly obsolete today.

How did you two come up with this idea? How did you get started working together?

Dr. Roy: I had just begun my career as a research biomedical engineer when I met Dr. William Fissell, who was then contemplating a career in nephrology. He opened my eyes to the problems faced by patients affected by kidney failure. Through our discussions, we quickly realized that while we could improve dialysis machines, patients needed and deserved something better – a treatment that improves their health while also allowing them to keep a job, travel readily, and consume food and drink without restrictions. Basically, something that works more like a kidney transplant.

How does the artificial kidney differ from dialysis?

Dr. Fissell: Dialysis is an intermittent stop-and-start treatment. The artificial kidney is continuous, around-the-clock treatment. There are a couple of advantages to that. The first is that you can maintain your body’s fluid balance. In dialysis, you get rid of 2-3 days’ worth of fluid in a couple of hours, and that’s very stressful to the heart and maybe to the brain as well. Second advantage is that patients will be able to eat a normal diet. Some waste products that are byproducts of our nutritional intake are slow to leave the body. So in dialysis, we restrict the diet severely and add medicines to soak up extra phosphorus. With a continuous treatment, you can balance excretion and intake.

The other aspect is that dialysis requires an immense amount of disposables. Hundreds of liters of water per patient per treatment, hundreds of thousands of dialysis cartridges and IV bags every year. The artificial kidney doesn’t need a water supply, disposable sorbent, or cartridges.
 

How does the artificial kidney work?

Dr. Fissell: Just like a healthy kidney. We have a unit that filters the blood so that red blood cells, white blood cells, platelets, antibodies, albumin – all the good stuff that your body worked hard to synthesize – stays in the blood, but a watery soup of toxins and waste is separated out. In a second unit, called the bioreactor, kidney cells concentrate those wastes and toxins into urine.

Dr. Roy: We used a technology called silicon micro-machining to invent an entirely new membrane that mimics a healthy kidney’s filters. It filters the blood just using the patient’s heart as a pump. No electric motors, no batteries, no wires. This lets us have something that’s completely implanted.

We also developed a cell culture of kidney cells that function in an artificial kidney. Normally, cells in a dish don’t fully adopt the features of a cell in the body. We looked at the literature around 3-D printing of organs. We learned that, in addition to fluid flow, stiff scaffolds, like cell culture dishes, trigger specific signals that keep the cells from functioning. We overcame that by looking at the physical microenvironment of the cells –  not the hormones and proteins, but instead the fundamentals of the laboratory environment. For example, most organs are soft, yet plastic lab dishes are hard. By using tools that replicated the softness and fluid flow of a healthy kidney, remarkably, these cells functioned better than on a plastic dish.
 

Would patients need immunosuppressive or anticoagulation medication?

Dr. Fissell: They wouldn’t need either. The structure and chemistry of the device prevents blood from clotting. And the membranes in the device are a physical barrier between the host immune system and the donor cells, so the body won’t reject the device.

What is the state of the technology now?

Dr. Fissell: We have shown the function of the filters and the function of the cells, both separately and together, in preclinical in vivo testing. What we now need to do is construct clinical-grade devices and complete sterility and biocompatibility testing to initiate a human trial. That’s going to take between $12 million and $15 million in device manufacturing.

So it’s more a matter of money than time until the first clinical trials?

Dr. Roy: Yes, exactly. We don’t like to say that a clinical trial will start by such-and-such year. From the very start of the project, we have been resource limited.

A version of this article first appeared on Medscape.com.

Researchers in Texas are developing a “green light” technology they hope will solve a crucial problem highlighted by the pandemic: the limits of pulse oximeters in patients with darker skin.

A recent study adds weight to earlier findings that their device works. 

“It is a new, first-in-class technology,” said Sanjay Gokhale, MD, the bioengineer who is leading this research at the University of Texas at Arlington. “The team conducted extensive preclinical work and carried out phase 1 studies in human volunteers, demonstrating sensitivity and accuracy.”

It’s one of several projects underway to update pulse oximetry, a technology based on research in lighter-skinned people that has not changed much in 50 years. 

The pulse oximeter, or “pulse ox,” measures the saturation of oxygen in your hemoglobin (a protein in red blood cells). But it tends to overestimate the oxygen saturation in patients with darker skin by about 2%-3%. That may not sound like a lot, but it’s enough to delay major treatment for respiratory issues like COVID-19. 

“Falsely elevated readings from commercial oximeters have delayed treatment of Black COVID-19 patients for hours in some cases,” said Divya Chander, MD, PhD, an anesthesiologist in Oakland, Calif., and chair of neuroscience at The Singularity Group. (Dr. Chander was not involved in the UT Arlington research.)

Early research happening separately at Brown University and Tufts University aims to redesign the pulse oximeter to get accurate readings in patients of all skin tones. University of California, San Diego, researchers are looking into a method that measures blood oxygen using sound in combination with light.  Other solutions try to correct for skin tone with algorithms. 

The device from UT Arlington uses an algorithm too, but its main innovation is that it replaces red light with green light. 
 

Red light, green light

Traditional oximetry devices, which typically clip on to the patient’s fingertip, use LEDs to beam light through the skin at two wavelengths: one in the red part of the spectrum, the other in the infrared. The light transmits from one side of the clip to the other, passing through arterial blood as it pulses.

The device calculates a patient’s oxygenation based on how much light of each wavelength is absorbed by hemoglobin in the blood. Oxygenated hemoglobin absorbs the light differently than deoxygenated hemoglobin, so oxygenation can be represented as a percentage; 100% means all hemoglobin is completely oxygenated.  But the melanin in skin can interfere with the absorption of light and affect the results. 

The green light strategy measures not absorption but reflectance – how much of the light bounces back. As with traditional oximetry, the green-light method uses two wavelengths. Each is a different shade of green, and the two forms of hemoglobin reflect them differently. 

Using an algorithm developed by the researchers, the device can capture readings in patients of all skin tones, the researchers say. And because it works on the wrist rather than a finger, the device also eliminates issues with cold fingers and dark nail polish – both known to reduce accuracy in traditional oximetry.

In the latest experiments, the researchers tested the technology on synthetic skin samples with varying amounts of melanin, Dr. Gokhale said. The device picked up changes in blood oxygen saturation even in samples with high melanin levels. 

In a study published last year, the technology was tested in 16 people against an invasive handheld blood analyzer and a noninvasive commercial pulse oximeter, and found to be comparable to the invasive method. 
 

A drawback 

The green light approach could be “game changing,” Dr. Chander said. But there is a drawback. 

Since green light doesn’t penetrate as deeply, this approach measures blood oxygen saturation in capillary beds (small blood vessels very close to the skin surface). By contrast, traditional oximetry measures oxygen saturation in an artery as it pulses – thus the name pulse oximetry. 

Valuable information can be obtained from an arterial pulse.

Changes in arterial pulse, known as the waveforms, “can tell us about a patient’s hydration status [for instance],” Dr. Chander said. “In a mechanically ventilated patient, this variation with a patient’s respiratory cycle can give us feedback about how responsive the patient will be to fluid resuscitation if their blood pressure is too low.” 

Given such considerations, the green light method may be useful as an adjunct, not a full replacement, to a standard pulse ox, Dr. Chander noted.

A version of this article appeared on WebMD.com.

Researchers in Texas are developing a “green light” technology they hope will solve a crucial problem highlighted by the pandemic: the limits of pulse oximeters in patients with darker skin.

A recent study adds weight to earlier findings that their device works. 

“It is a new, first-in-class technology,” said Sanjay Gokhale, MD, the bioengineer who is leading this research at the University of Texas at Arlington. “The team conducted extensive preclinical work and carried out phase 1 studies in human volunteers, demonstrating sensitivity and accuracy.”

It’s one of several projects underway to update pulse oximetry, a technology based on research in lighter-skinned people that has not changed much in 50 years. 

The pulse oximeter, or “pulse ox,” measures the saturation of oxygen in your hemoglobin (a protein in red blood cells). But it tends to overestimate the oxygen saturation in patients with darker skin by about 2%-3%. That may not sound like a lot, but it’s enough to delay major treatment for respiratory issues like COVID-19. 

“Falsely elevated readings from commercial oximeters have delayed treatment of Black COVID-19 patients for hours in some cases,” said Divya Chander, MD, PhD, an anesthesiologist in Oakland, Calif., and chair of neuroscience at The Singularity Group. (Dr. Chander was not involved in the UT Arlington research.)

Early research happening separately at Brown University and Tufts University aims to redesign the pulse oximeter to get accurate readings in patients of all skin tones. University of California, San Diego, researchers are looking into a method that measures blood oxygen using sound in combination with light.  Other solutions try to correct for skin tone with algorithms. 

The device from UT Arlington uses an algorithm too, but its main innovation is that it replaces red light with green light. 
 

Red light, green light

Traditional oximetry devices, which typically clip on to the patient’s fingertip, use LEDs to beam light through the skin at two wavelengths: one in the red part of the spectrum, the other in the infrared. The light transmits from one side of the clip to the other, passing through arterial blood as it pulses.

The device calculates a patient’s oxygenation based on how much light of each wavelength is absorbed by hemoglobin in the blood. Oxygenated hemoglobin absorbs the light differently than deoxygenated hemoglobin, so oxygenation can be represented as a percentage; 100% means all hemoglobin is completely oxygenated.  But the melanin in skin can interfere with the absorption of light and affect the results. 

The green light strategy measures not absorption but reflectance – how much of the light bounces back. As with traditional oximetry, the green-light method uses two wavelengths. Each is a different shade of green, and the two forms of hemoglobin reflect them differently. 

Using an algorithm developed by the researchers, the device can capture readings in patients of all skin tones, the researchers say. And because it works on the wrist rather than a finger, the device also eliminates issues with cold fingers and dark nail polish – both known to reduce accuracy in traditional oximetry.

In the latest experiments, the researchers tested the technology on synthetic skin samples with varying amounts of melanin, Dr. Gokhale said. The device picked up changes in blood oxygen saturation even in samples with high melanin levels. 

In a study published last year, the technology was tested in 16 people against an invasive handheld blood analyzer and a noninvasive commercial pulse oximeter, and found to be comparable to the invasive method. 
 

A drawback 

The green light approach could be “game changing,” Dr. Chander said. But there is a drawback. 

Since green light doesn’t penetrate as deeply, this approach measures blood oxygen saturation in capillary beds (small blood vessels very close to the skin surface). By contrast, traditional oximetry measures oxygen saturation in an artery as it pulses – thus the name pulse oximetry. 

Valuable information can be obtained from an arterial pulse.

Changes in arterial pulse, known as the waveforms, “can tell us about a patient’s hydration status [for instance],” Dr. Chander said. “In a mechanically ventilated patient, this variation with a patient’s respiratory cycle can give us feedback about how responsive the patient will be to fluid resuscitation if their blood pressure is too low.” 

Given such considerations, the green light method may be useful as an adjunct, not a full replacement, to a standard pulse ox, Dr. Chander noted.

A version of this article appeared on WebMD.com.

Researchers in Texas are developing a “green light” technology they hope will solve a crucial problem highlighted by the pandemic: the limits of pulse oximeters in patients with darker skin.

A recent study adds weight to earlier findings that their device works. 

“It is a new, first-in-class technology,” said Sanjay Gokhale, MD, the bioengineer who is leading this research at the University of Texas at Arlington. “The team conducted extensive preclinical work and carried out phase 1 studies in human volunteers, demonstrating sensitivity and accuracy.”

It’s one of several projects underway to update pulse oximetry, a technology based on research in lighter-skinned people that has not changed much in 50 years. 

The pulse oximeter, or “pulse ox,” measures the saturation of oxygen in your hemoglobin (a protein in red blood cells). But it tends to overestimate the oxygen saturation in patients with darker skin by about 2%-3%. That may not sound like a lot, but it’s enough to delay major treatment for respiratory issues like COVID-19. 

“Falsely elevated readings from commercial oximeters have delayed treatment of Black COVID-19 patients for hours in some cases,” said Divya Chander, MD, PhD, an anesthesiologist in Oakland, Calif., and chair of neuroscience at The Singularity Group. (Dr. Chander was not involved in the UT Arlington research.)

Early research happening separately at Brown University and Tufts University aims to redesign the pulse oximeter to get accurate readings in patients of all skin tones. University of California, San Diego, researchers are looking into a method that measures blood oxygen using sound in combination with light.  Other solutions try to correct for skin tone with algorithms. 

The device from UT Arlington uses an algorithm too, but its main innovation is that it replaces red light with green light. 
 

Red light, green light

Traditional oximetry devices, which typically clip on to the patient’s fingertip, use LEDs to beam light through the skin at two wavelengths: one in the red part of the spectrum, the other in the infrared. The light transmits from one side of the clip to the other, passing through arterial blood as it pulses.

The device calculates a patient’s oxygenation based on how much light of each wavelength is absorbed by hemoglobin in the blood. Oxygenated hemoglobin absorbs the light differently than deoxygenated hemoglobin, so oxygenation can be represented as a percentage; 100% means all hemoglobin is completely oxygenated.  But the melanin in skin can interfere with the absorption of light and affect the results. 

The green light strategy measures not absorption but reflectance – how much of the light bounces back. As with traditional oximetry, the green-light method uses two wavelengths. Each is a different shade of green, and the two forms of hemoglobin reflect them differently. 

Using an algorithm developed by the researchers, the device can capture readings in patients of all skin tones, the researchers say. And because it works on the wrist rather than a finger, the device also eliminates issues with cold fingers and dark nail polish – both known to reduce accuracy in traditional oximetry.

In the latest experiments, the researchers tested the technology on synthetic skin samples with varying amounts of melanin, Dr. Gokhale said. The device picked up changes in blood oxygen saturation even in samples with high melanin levels. 

In a study published last year, the technology was tested in 16 people against an invasive handheld blood analyzer and a noninvasive commercial pulse oximeter, and found to be comparable to the invasive method. 
 

A drawback 

The green light approach could be “game changing,” Dr. Chander said. But there is a drawback. 

Since green light doesn’t penetrate as deeply, this approach measures blood oxygen saturation in capillary beds (small blood vessels very close to the skin surface). By contrast, traditional oximetry measures oxygen saturation in an artery as it pulses – thus the name pulse oximetry. 

Valuable information can be obtained from an arterial pulse.

Changes in arterial pulse, known as the waveforms, “can tell us about a patient’s hydration status [for instance],” Dr. Chander said. “In a mechanically ventilated patient, this variation with a patient’s respiratory cycle can give us feedback about how responsive the patient will be to fluid resuscitation if their blood pressure is too low.” 

Given such considerations, the green light method may be useful as an adjunct, not a full replacement, to a standard pulse ox, Dr. Chander noted.

A version of this article appeared on WebMD.com.

When I was a child, I watched syndicated episodes of the original “Star Trek.” I was dazzled by the space travel, sure, but also the medical technology.

A handheld “tricorder” detected diseases, while an intramuscular injector (“hypospray”) could treat them. Sickbay “biobeds” came with real-time health monitors that looked futuristic at the time but seem primitive today.

Such visions inspired a lot of us kids to pursue science. Little did we know the real-life advances many of us would see in our lifetimes.

Artificial intelligence helping to spot disease, robots performing surgery, even video calls between doctor and patient – all these once sounded fantastical but now happen in clinical care.

Now, in the 23rd year of the 21st century, you might not believe wht we’ll be capable of next. Three especially wild examples are moving closer to clinical reality. 
 

Human hibernation

Captain America, Han Solo, and “Star Trek” villain Khan – all were preserved at low temperatures and then revived, waking up alive and well months, decades, or centuries later. These are fictional examples, to be sure, but the science they’re rooted in is real.

Rare cases of accidental hypothermia prove that full recovery is possible even after the heart stops beating. The drop in body temperature slows metabolism and reduces the need for oxygen, stalling brain damage for an hour or more. (In one extreme case, a climber survived after almost 9 hours of efforts to revive him.)

Useful for a space traveler? Maybe not. But it’s potentially huge for someone with life-threatening injuries from a car accident or a gunshot wound.

That’s the thinking behind a breakthrough procedure that came after decades of research on pigs and dogs, now in a clinical trial. The idea: A person with massive blood loss whose heart has stopped is injected with an ice-cold fluid, cooling them from the inside, down to about 50° F.

Doctors already induce more modest hypothermia to protect the brain and other organs after cardiac arrest and during surgery on the aortic arch (the main artery carrying blood from the heart).

But this experimental procedure – called emergency preservation and resuscitation (EPR) – goes far beyond that, dramatically “decreasing the body’s need for oxygen and blood flow,” says Samuel Tisherman, MD, a trauma surgeon at the University of Maryland Medical Center and the trial’s lead researcher. This puts the patient in a state of suspended animation that “could buy time for surgeons to stop the bleeding and save more of these patients.”

The technique has been done on at least six patients, though none were reported to survive. The trial is expected to include 20 people by the time it wraps up in December, according to the listing on the U.S. clinical trials database. Though given the strict requirements for candidates (emergency trauma victims who are not likely to survive), one can’t exactly rely on a set schedule.

Still, the technology is promising. Someday we may even use it to keep patients in suspended animation for months or years, experts predict, helping astronauts through decades-long spaceflights, or stalling death in sick patients awaiting a cure.
 

Artificial womb

Another sci-fi classic: growing human babies outside the womb. Think the fetus fields from “The Matrix,” or the frozen embryos in “Alien: Covenant.”

In 1923, British biologist J.B.S. Haldane coined a term for that – ectogenesis. He predicted that 70% of pregnancies would take place, from fertilization to birth, in artificial wombs by 2074. That many seems unlikely, but the timeline is on track.

Developing an embryo outside the womb is already routine in in vitro fertilization. And technology enables preterm babies to survive through much of the second half of gestation. Normal human pregnancy is 40 weeks, and the youngest preterm baby ever to survive was 21 weeks and 1 day old, just a few days younger than a smattering of others who lived.

The biggest obstacle for babies younger than that is lung viability. Mechanical ventilation can damage the lungs and lead to a chronic (sometimes fatal) lung disease known as bronchopulmonary dysplasia. Avoiding this would mean figuring out a way to maintain fetal circulation – the intricate system that delivers oxygenated blood from the placenta to the fetus via the umbilical cord. Researchers at Children’s Hospital of Philadelphia have done this using a fetal lamb.

The key to their invention is a substitute placenta: an oxygenator connected to the lamb’s umbilical cord. Tubes inserted through the umbilical vein and arteries carry oxygenated blood from the “placenta” to the fetus, and deoxygenated blood back out. The lamb resides in an artificial, fluid-filled amniotic sac until its lungs and other organs are developed.

Fertility treatment could benefit, too. “An artificial womb may substitute in situations in which a gestational carrier – surrogate – is indicated,” says Paula Amato, MD, a professor of obstetrics and gynecology at Oregon Health and Science University, Portland. (Dr. Amato is not involved in the CHOP research.) For example: when the mother is missing a uterus or can’t carry a pregnancy safely.

No date is set for clinical trials yet. But according to the research, the main difference between human and lamb may come down to size. A lamb’s umbilical vessels are larger, so feeding in a tube is easier. With today’s advances in miniaturizing surgical methods, that seems like a challenge scientists can overcome.
 

Messenger RNA therapeutics

Back to “Star Trek.” The hypospray injector’s contents could cure just about any disease, even one newly discovered on a strange planet. That’s not unlike messenger RNA (mRNA) technology, a breakthrough that enabled scientists to quickly develop some of the first COVID-19 vaccines.

But vaccines are just the beginning of what this technology can do.

A whole field of immunotherapy is emerging that uses mRNA to deliver instructions to produce chimeric antigen receptor–modified immune cells (CAR-modified immune cells). These cells are engineered to target diseased cells and tissues, like cancer cells and harmful fibroblasts (scar tissue) that promote fibrosis in, for example, the heart and lungs.

The field is bursting with rodent research, and clinical trials have started for treating some advanced-stage malignancies.

Actual clinical use may be years away, but if all goes well, these medicines could help treat or even cure the core medical problems facing humanity. We’re talking cancer, heart disease, neurodegenerative disease – transforming one therapy into another by simply changing the mRNA’s “nucleotide sequence,” the blueprint containing instructions telling it what to do, and what disease to attack.

As this technology matures, we may start to feel as if we’re really on “Star Trek,” where Dr. Leonard “Bones” McCoy pulls out the same device to treat just about every disease or injury.

A version of this article first appeared on WebMD.com.

When I was a child, I watched syndicated episodes of the original “Star Trek.” I was dazzled by the space travel, sure, but also the medical technology.

A handheld “tricorder” detected diseases, while an intramuscular injector (“hypospray”) could treat them. Sickbay “biobeds” came with real-time health monitors that looked futuristic at the time but seem primitive today.

Such visions inspired a lot of us kids to pursue science. Little did we know the real-life advances many of us would see in our lifetimes.

Artificial intelligence helping to spot disease, robots performing surgery, even video calls between doctor and patient – all these once sounded fantastical but now happen in clinical care.

Now, in the 23rd year of the 21st century, you might not believe wht we’ll be capable of next. Three especially wild examples are moving closer to clinical reality. 
 

Human hibernation

Captain America, Han Solo, and “Star Trek” villain Khan – all were preserved at low temperatures and then revived, waking up alive and well months, decades, or centuries later. These are fictional examples, to be sure, but the science they’re rooted in is real.

Rare cases of accidental hypothermia prove that full recovery is possible even after the heart stops beating. The drop in body temperature slows metabolism and reduces the need for oxygen, stalling brain damage for an hour or more. (In one extreme case, a climber survived after almost 9 hours of efforts to revive him.)

Useful for a space traveler? Maybe not. But it’s potentially huge for someone with life-threatening injuries from a car accident or a gunshot wound.

That’s the thinking behind a breakthrough procedure that came after decades of research on pigs and dogs, now in a clinical trial. The idea: A person with massive blood loss whose heart has stopped is injected with an ice-cold fluid, cooling them from the inside, down to about 50° F.

Doctors already induce more modest hypothermia to protect the brain and other organs after cardiac arrest and during surgery on the aortic arch (the main artery carrying blood from the heart).

But this experimental procedure – called emergency preservation and resuscitation (EPR) – goes far beyond that, dramatically “decreasing the body’s need for oxygen and blood flow,” says Samuel Tisherman, MD, a trauma surgeon at the University of Maryland Medical Center and the trial’s lead researcher. This puts the patient in a state of suspended animation that “could buy time for surgeons to stop the bleeding and save more of these patients.”

The technique has been done on at least six patients, though none were reported to survive. The trial is expected to include 20 people by the time it wraps up in December, according to the listing on the U.S. clinical trials database. Though given the strict requirements for candidates (emergency trauma victims who are not likely to survive), one can’t exactly rely on a set schedule.

Still, the technology is promising. Someday we may even use it to keep patients in suspended animation for months or years, experts predict, helping astronauts through decades-long spaceflights, or stalling death in sick patients awaiting a cure.
 

Artificial womb

Another sci-fi classic: growing human babies outside the womb. Think the fetus fields from “The Matrix,” or the frozen embryos in “Alien: Covenant.”

In 1923, British biologist J.B.S. Haldane coined a term for that – ectogenesis. He predicted that 70% of pregnancies would take place, from fertilization to birth, in artificial wombs by 2074. That many seems unlikely, but the timeline is on track.

Developing an embryo outside the womb is already routine in in vitro fertilization. And technology enables preterm babies to survive through much of the second half of gestation. Normal human pregnancy is 40 weeks, and the youngest preterm baby ever to survive was 21 weeks and 1 day old, just a few days younger than a smattering of others who lived.

The biggest obstacle for babies younger than that is lung viability. Mechanical ventilation can damage the lungs and lead to a chronic (sometimes fatal) lung disease known as bronchopulmonary dysplasia. Avoiding this would mean figuring out a way to maintain fetal circulation – the intricate system that delivers oxygenated blood from the placenta to the fetus via the umbilical cord. Researchers at Children’s Hospital of Philadelphia have done this using a fetal lamb.

The key to their invention is a substitute placenta: an oxygenator connected to the lamb’s umbilical cord. Tubes inserted through the umbilical vein and arteries carry oxygenated blood from the “placenta” to the fetus, and deoxygenated blood back out. The lamb resides in an artificial, fluid-filled amniotic sac until its lungs and other organs are developed.

Fertility treatment could benefit, too. “An artificial womb may substitute in situations in which a gestational carrier – surrogate – is indicated,” says Paula Amato, MD, a professor of obstetrics and gynecology at Oregon Health and Science University, Portland. (Dr. Amato is not involved in the CHOP research.) For example: when the mother is missing a uterus or can’t carry a pregnancy safely.

No date is set for clinical trials yet. But according to the research, the main difference between human and lamb may come down to size. A lamb’s umbilical vessels are larger, so feeding in a tube is easier. With today’s advances in miniaturizing surgical methods, that seems like a challenge scientists can overcome.
 

Messenger RNA therapeutics

Back to “Star Trek.” The hypospray injector’s contents could cure just about any disease, even one newly discovered on a strange planet. That’s not unlike messenger RNA (mRNA) technology, a breakthrough that enabled scientists to quickly develop some of the first COVID-19 vaccines.

But vaccines are just the beginning of what this technology can do.

A whole field of immunotherapy is emerging that uses mRNA to deliver instructions to produce chimeric antigen receptor–modified immune cells (CAR-modified immune cells). These cells are engineered to target diseased cells and tissues, like cancer cells and harmful fibroblasts (scar tissue) that promote fibrosis in, for example, the heart and lungs.

The field is bursting with rodent research, and clinical trials have started for treating some advanced-stage malignancies.

Actual clinical use may be years away, but if all goes well, these medicines could help treat or even cure the core medical problems facing humanity. We’re talking cancer, heart disease, neurodegenerative disease – transforming one therapy into another by simply changing the mRNA’s “nucleotide sequence,” the blueprint containing instructions telling it what to do, and what disease to attack.

As this technology matures, we may start to feel as if we’re really on “Star Trek,” where Dr. Leonard “Bones” McCoy pulls out the same device to treat just about every disease or injury.

A version of this article first appeared on WebMD.com.

When I was a child, I watched syndicated episodes of the original “Star Trek.” I was dazzled by the space travel, sure, but also the medical technology.

A handheld “tricorder” detected diseases, while an intramuscular injector (“hypospray”) could treat them. Sickbay “biobeds” came with real-time health monitors that looked futuristic at the time but seem primitive today.

Such visions inspired a lot of us kids to pursue science. Little did we know the real-life advances many of us would see in our lifetimes.

Artificial intelligence helping to spot disease, robots performing surgery, even video calls between doctor and patient – all these once sounded fantastical but now happen in clinical care.

Now, in the 23rd year of the 21st century, you might not believe wht we’ll be capable of next. Three especially wild examples are moving closer to clinical reality. 
 

Human hibernation

Captain America, Han Solo, and “Star Trek” villain Khan – all were preserved at low temperatures and then revived, waking up alive and well months, decades, or centuries later. These are fictional examples, to be sure, but the science they’re rooted in is real.

Rare cases of accidental hypothermia prove that full recovery is possible even after the heart stops beating. The drop in body temperature slows metabolism and reduces the need for oxygen, stalling brain damage for an hour or more. (In one extreme case, a climber survived after almost 9 hours of efforts to revive him.)

Useful for a space traveler? Maybe not. But it’s potentially huge for someone with life-threatening injuries from a car accident or a gunshot wound.

That’s the thinking behind a breakthrough procedure that came after decades of research on pigs and dogs, now in a clinical trial. The idea: A person with massive blood loss whose heart has stopped is injected with an ice-cold fluid, cooling them from the inside, down to about 50° F.

Doctors already induce more modest hypothermia to protect the brain and other organs after cardiac arrest and during surgery on the aortic arch (the main artery carrying blood from the heart).

But this experimental procedure – called emergency preservation and resuscitation (EPR) – goes far beyond that, dramatically “decreasing the body’s need for oxygen and blood flow,” says Samuel Tisherman, MD, a trauma surgeon at the University of Maryland Medical Center and the trial’s lead researcher. This puts the patient in a state of suspended animation that “could buy time for surgeons to stop the bleeding and save more of these patients.”

The technique has been done on at least six patients, though none were reported to survive. The trial is expected to include 20 people by the time it wraps up in December, according to the listing on the U.S. clinical trials database. Though given the strict requirements for candidates (emergency trauma victims who are not likely to survive), one can’t exactly rely on a set schedule.

Still, the technology is promising. Someday we may even use it to keep patients in suspended animation for months or years, experts predict, helping astronauts through decades-long spaceflights, or stalling death in sick patients awaiting a cure.
 

Artificial womb

Another sci-fi classic: growing human babies outside the womb. Think the fetus fields from “The Matrix,” or the frozen embryos in “Alien: Covenant.”

In 1923, British biologist J.B.S. Haldane coined a term for that – ectogenesis. He predicted that 70% of pregnancies would take place, from fertilization to birth, in artificial wombs by 2074. That many seems unlikely, but the timeline is on track.

Developing an embryo outside the womb is already routine in in vitro fertilization. And technology enables preterm babies to survive through much of the second half of gestation. Normal human pregnancy is 40 weeks, and the youngest preterm baby ever to survive was 21 weeks and 1 day old, just a few days younger than a smattering of others who lived.

The biggest obstacle for babies younger than that is lung viability. Mechanical ventilation can damage the lungs and lead to a chronic (sometimes fatal) lung disease known as bronchopulmonary dysplasia. Avoiding this would mean figuring out a way to maintain fetal circulation – the intricate system that delivers oxygenated blood from the placenta to the fetus via the umbilical cord. Researchers at Children’s Hospital of Philadelphia have done this using a fetal lamb.

The key to their invention is a substitute placenta: an oxygenator connected to the lamb’s umbilical cord. Tubes inserted through the umbilical vein and arteries carry oxygenated blood from the “placenta” to the fetus, and deoxygenated blood back out. The lamb resides in an artificial, fluid-filled amniotic sac until its lungs and other organs are developed.

Fertility treatment could benefit, too. “An artificial womb may substitute in situations in which a gestational carrier – surrogate – is indicated,” says Paula Amato, MD, a professor of obstetrics and gynecology at Oregon Health and Science University, Portland. (Dr. Amato is not involved in the CHOP research.) For example: when the mother is missing a uterus or can’t carry a pregnancy safely.

No date is set for clinical trials yet. But according to the research, the main difference between human and lamb may come down to size. A lamb’s umbilical vessels are larger, so feeding in a tube is easier. With today’s advances in miniaturizing surgical methods, that seems like a challenge scientists can overcome.
 

Messenger RNA therapeutics

Back to “Star Trek.” The hypospray injector’s contents could cure just about any disease, even one newly discovered on a strange planet. That’s not unlike messenger RNA (mRNA) technology, a breakthrough that enabled scientists to quickly develop some of the first COVID-19 vaccines.

But vaccines are just the beginning of what this technology can do.

A whole field of immunotherapy is emerging that uses mRNA to deliver instructions to produce chimeric antigen receptor–modified immune cells (CAR-modified immune cells). These cells are engineered to target diseased cells and tissues, like cancer cells and harmful fibroblasts (scar tissue) that promote fibrosis in, for example, the heart and lungs.

The field is bursting with rodent research, and clinical trials have started for treating some advanced-stage malignancies.

Actual clinical use may be years away, but if all goes well, these medicines could help treat or even cure the core medical problems facing humanity. We’re talking cancer, heart disease, neurodegenerative disease – transforming one therapy into another by simply changing the mRNA’s “nucleotide sequence,” the blueprint containing instructions telling it what to do, and what disease to attack.

As this technology matures, we may start to feel as if we’re really on “Star Trek,” where Dr. Leonard “Bones” McCoy pulls out the same device to treat just about every disease or injury.

A version of this article first appeared on WebMD.com.