Making it safer to transport infected patients

The Complete Engineering® Podcast

Making it safer to transport infected patients

The problems just keep growing, and we solve one problem and a new problem pops up again. It's new and exciting every day and you get to really see the lives that you're touching. Engineering and public health both save lives.

Kelli Herstein
Assistant Professor of Practice, Durham School of Architectural Engineering & Construction
For this episode of the Complete Engineering podcast, we're talking to Terry Stentz and Kelli Herstein, faculty from The Durham School of Architectural Engineering and Construction. Terry and Kelli discuss their work with the Department of Defense to make the process of transporting patients exposed to infectious diseases safer for the healthcare workers and other Air Force personnel on those missions.

Terry Stentz and Kelli Herstein, faculty from The Durham School of Architectural Engineering and Construction, pose with military members.
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Intro: The problems just keep growing and we'd solve one problem and a new problem pops up again and it's new and exciting every day and you get to really see the lives that you're touching. This engineering and public health will save lives.

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Karl Vogel: Welcome to the Complete Engineering podcast. My name is Karl Vogel and at the time of this recording the outbreak of the Novel Coronavirus, COVID-19, has become a big public topic around the world, especially in the area of public health and safety. In February, Nebraska was at the center of attention with patients being transported to the University of Nebraska Medical Center in Omaha for treatment and Camp Ashland for a quarantine and it's not the first time that UNMC has been in the international spotlight with patients infected with Ebola being brought to the bio containment unit there in 2014. The University of Nebraska Lincoln College of Engineering is playing a key role in evaluating the processes used to transport patients, especially by the Defense Department in the Air Force. Today we're talking with Terry Stents and Kelly Herstein, they're faculty in the Durham School of Architectural Engineering and Construction. And they have recently, in the last few years done some work on a study with the Air Force's airborne bio containment unit involving the transport of patients who have been infected with an infectious disease. We're gonna talk to them about the processes involved and what they've learned about the process of transporting these patients. Welcome to the podcast today.

Kelli Herstein and Terry Stentz: Thank you for having us. Thank you very much.

Karl Vogel: Now, what is it that you were studying and you were looking into in this project you worked with and who were you working with?

Terry Stentz: This was a Department of Defense funded research project. The contractors with UNMC, the bio containment folks in the College of Public Health in the College of Medicine, and the whole idea of this study, over a one to two year period, was to evaluate the performance of the transport isolation system in terms of a whole series of parameters to make sure that the 24/7, this type of evacuation and transport of highly infected patients could be done and be assured that it would come off the way it's supposed to perform. And so our part was to play the human factors, ergonomics and safety aspects, crew performance, for that particular exercise.

Karl Vogel: You guys are both occupational safety, you're ergonomics, human factors experts. What things did you draw on from that experience in these projects?

Kelli Herstein: Well, we're both industrial engineers and so we have degrees from University of Nebraska in industrial engineering and we use a lot of the experience that we had into that education working with humans and ergonomics, human factors and we work with humans all the time in construction, so construction is a very human-centered field and that translated well to our research in public health.

Karl Vogel: Terry, I talked to you previously about a project that you had done with iron workers, measuring the data about job site safety, was that similar to some of the work that was done in this project with the Air Force?

Terry Stentz: The overall idea was similar in terms of human factors and safety but in that particular case, iron workers are at high risk for falls and when they fall, if they're not protected, they die. And we're very interested in studying their gait, when they walk along a steel beam, they're carrying 65 pounds of tools and safety harness stuff and they've told us anecdotally that the second half of their work day they're tired. And when you're up that high in the air, and you're walking around, your body movements, your gait, the speed that you work, and how you handle yourself changes. We want to analyze that and so we devised a series of experiments that actually collected data on the gait and the change in gait, as iron workers could walk across the steel beam, not at elevation, just up off the floor a little ways. And we've been studying that for about four and a half years, and we've come away with some real interesting things about human movement, kind of like a circus performer and how they can change these things and how we can modify the coatings on steel beams to make them less slippery. Because some coatings are more slippery than others and ironworkers will tell you that, but no one's ever measured it before. So we've done friction testing on different types of coated steel beams. And then we put human subjects with instrumentation, wireless instrumentation on their extremities, and have them walk these steel beams with and without tool belts, with only a toolbox or not. And we can detect changes in gait. And we can detect the amount the grade of friction that's on a steel beam coating. So in end, we can recommend architects and engineers, here's the coatings you need to do to make the job safer at elevation for iron workers, which we never knew before.

Karl Vogel: Was there a lot of that similar stuff, similar things that were part of this DOD and Air Force study that you were studying surfaces, you're studying what the healthcare workers were carrying, those types of things.

Kelli Herstein: Absolutely, yes. And then we've also done research with looking at locomotive train engineers and their fatigue and using self reported assessments on their fatigue levels. And we use that experience to draw on the fatigue levels of healthcare workers.

Terry Stentz: There are slips, trips and fall hazards in this TIS operation. And we did identify a few things that could be improved. But we were very concerned about fatigue, crew fatigue, we knew these missions are going to be extremely long. Longer than train crews drive a train over the road.

Karl Vogel: What would be a length of a mission?

Terry Stentz: They told us 24 hours or more.

Kelli Herstein: Yes, because the mission begins when you leave the United States and you have to fly to wherever you're picking up your patient from and then bring them back and you're under high stress situations. You might be going into a situation that unstable. You might have a critical patient that's gonna require a lot of care.

Karl Vogel: Right and unlike the iron workers who can, we assume can go home and sleep at night, these people that are doing the work here are up 24 hours or longer. Do they do they get much sleep? Do they get much of a chance to rest while they're in route either to their or back to the hospital?

Kelli Herstein: There are litter's setup where they can sleep but a litter if you think about if you've ever watched the show Mash, it's just cot that's stretched out between two poles. So it's not exactly comfortable. It's also very loud. There's a lot of movement going on. And so the quality of sleep, there was not an opportunity to sleep on the test mission that we did, but we did monitor their sleep using (mumbles) for two days before and two days after, to look at if sleep played a role in their fatigue levels.

Terry Stentz: For instance, if you got a call and had to report for a mission within just a few hours and you just done a 24 hour duty cycle on an airbase, you don't get a chance to sleep. You go where you're told to go and you do the mission. And so we wanted to take a look at those factors that were involved in terms of sleep, refreshment, and preparation. In the military, you have to learn to do without sleep. And in this case, this is a high vigilance task. You can't dope off. You've got to really focus all your attention on the TIS and on the patients that are very sick that you're transporting. So this is a vigilance expertise task pushed to the limit. And of course, we were concerned about measuring and analyzing the effects on the clinicians during this type of activity.

Karl Vogel: And it's fatigue, it's, I would assume nutrient related, losing electrolytes.

Terry Stentz: You can't eat inside the TIS and you can't drink anything in there.

Kelli Herstein: No, but the crews during the data simulation missions were eating and drinking outside of the TIS. All aeromedical evacuation people they do similar type missions, not with infectious patients, but maybe moving people who have been injured. So they're used to having to make sure that they keep up their nutrition and their water intake because when you're at height you dehydrate faster. And not to mention wearing that much PPE, you're constantly sweating and you're losing a lot of water sweat.

Terry Stentz: Your sweat rate is much higher. And we notice all the aircrew, our air crews have little backpacks, and they had water bottles on there and a little snack bars and things so they kinda knew how to handle that. But you can only do that outside the TIS. Then you have to clean up if you're going to go back in. You have to don all of your PPE or personal protective equipment and go back in there. So it's highly controlled.

Kelli Herstein: But if there's a breach, then all of that goes out the window and now everyone is in full PPE feeling the effects of that and maybe flying over an ocean there may be nowhere to land. And so you have to deal with that.

Terry Stentz: Once a mission is done, they clean that entire aircraft and the TIS. They have special cleaning equipment that goes through and sanitizes everything. Imagine landing on an Air Force Base or a civilian airfield with a contaminated aircraft. So that's another whole set of problems there, too that they have to handle. We know this is a 24/7 capability of the US Air Force. It's at the direction of the State Department. So if somebody has the coronavirus, the state department wants the military to transport. This would be the type of equipment they do in the Air Force unit that they would task. But as of right now, nobody's reporting C-17 airborne to go pick up somebody in Africa. But that could happen tomorrow. It could happen in the next hour.

Karl Vogel: They can evacuate the embassy in South Korea.

Terry Stentz: That's right. They are they are prepped 24/7. This is a built structure. It was designed and tested to 11G's. That's a lot of mechanical engineering. There's a lot of HVAC, heating ventilation air conditioning type, hepa filtering. This is an engineered environment. It has to perform a strict, highly infectious clinical job by humans for humans.

Kelli Herstein: And then you need to be able to offload it, put it in a hangar where it can go be disinfected, and then load people onto the aircraft or a tank or whatever else in a matter of minutes. You can't just contaminate the entire plane.

Terry Stentz: This is a flying medical engineering system. It has to all work.

Karl Vogel: Right. And we're not talking about small aircraft, we're talking cargo planes that carry thousands and thousands of pounds of equipment, typically tanks and motorized vehicles and the like. So how big are these planes and how big are the TIS's that are used to transport the patients?

Terry Stentz: Well, the C-17 is, the next largest aircraft would be a C-5 Galaxy, the one with the big nose that opens up. So we're talking about a very large transport aircraft that needs quite a bit of runway. The TIS units themselves are about 20 feet long, maybe eight feet wide, and maybe seven feet tall. They are kits that can be disassembled and reassembled. They are transportable in the racking and rail system inside of a military aircraft. And once you load those in the aircraft, it fills up pretty much the entire cargo bay. There's not a lot of room to move around. And all of the powered equipment, the air handling, the air filtering, the electrical, the electronics, all of those things is on the outside of the TIS. So you have this rectangular box envelope with all of this stuff on the outside. Once again, the boundaries are really important to maintain. It's a difficult built environment very much unlike most of what we're used to seeing in construction, except in the bio-containment unit at the hospital. And then you have to say, "what if we had to do that portable?" What kind of a structure would you have? How could you knock it down and build it back up? How could you clean it? How could you transport it from one one place to another? How could you store it for a long period of time, and then bring it out on a moment's notice, put it together, load it, make sure it all works and go airborne. This is a real performance trick. And that's what the Air Force does.

Karl Vogel: Did that inform maybe some processes that the Air Force is using? And what kind of recommendations did you make?

Terry Stentz: From our end probably a couple three recommendations. One is how crucial training is. Train, train, train. And one thing that is a concern is that when you have a military team that's trained to be able to deploy like this on a mission, they have to have continuity. In the military, you get transferred all around. So training is a huge issue. The second thing I think that we were able to do is point out how important continuing to work on ergonomics and safety is, We can't just stop here. We've got to keep making things better and better. And I think we put that on the radar screen. And I think the Air Force is going to have that on the radar screen and working with it for a long time to come. Probably the third thing we showed was that vigilance was pretty good. It wasn't perfect, but it was pretty good. We learned a lot about that. And secondly, that the biomechanical stressors on crew members was somewhat moderate, but some of the patient handling put a lot of back strain, a lot of shoulder strain on these folks. And you don't want these highly trained people to be injured. They've got to be able to perform. And so we pointed out some things that could be done there in patient handling, and maybe future modification of the TIS that would make the biomechanical stressors less.

Karl Vogel: Kelly actually got to observe a mission. You were part of a flight mission. that was a simulation. Tell us about that mission and what you observed.

Kelli Herstein: Yes, so it was very exciting. I got to fly with the aeromedical evacuation team and our partners, UNMC, and observed what was happening. And do testing at mid flight, which was pretty exciting. We had simulation patients. And so they were, we had real humans and we also had some mannequins and so simulating different scenarios that could happen. I'd never been on a military aircraft before. And so this was a new experience for me. I had been to Offutt a few times, but going to another Air Force Base, seeing the rows and rows of C-17. Just understanding how large those aircraft are. You go to SAC Airbase Museum over in Ashland, and those are some pretty impressive aircraft, but then you go see a C-17. It's a whole different ball of wax there. But these teams are really dedicated to what they do. And they're highly specialized. They were really happy that we were there doing this research. They had a lot of really great feedback. We were able to give some really solid recommendations that we think will help them but it was pretty exciting to be able to do that. I will say taking off and landing without any windows is definitely a thrill. But it was exciting.

Terry Stentz: Trying to recall, Kelly, did the missions start at Offutt or do they start in Charleston?

Kelli Herstein: It started in Charleston, flew over the Great Lakes just to add some more time because it's only a four hour flight between Charleston and Offutt. So we spent about eight hours just kind of moseying around the Great Lakes. I got to go up in the cockpit, look out the window, talk to the pilots and just kinda see flying in a whole different perspective. Also looking at how the pilots are able to sleep mid flight and talking to them giving them some recommendations on or just learning about how they do these long haul flights. Because this is very common for C-17 pilot to fly all over the world in long haul flights. And then on the way back, there were some storms coming in. And so we took the direct route home and ended up having some turbulence, which was great because, well it was a little scary I will say to be on a cargo flight during turbulence, but to be able to have that as part of our simulation and see what was kinda a worst case scenario that could happen and simulate some power failures landed in Charleston, ended up having some bad weather and we got stuck on the plane for about an hour and a half because of a lightning storm. But it gave us the opportunity to spend more time with the aeromedical evacuation team and decompress and figure out what how we can make the best suggestions.

Terry Stentz: They eventually landed in Offutt, offloaded patients and dummies or mannequins. And then they went airborne and flew back to Charleston. So it was like a round robin.

Kelli Herstein: And Terry and a team from the Med Center met us on the runway at Offutt to observe the offloading and to make recommendations for EMS.

Karl Vogel: Have these recommendations been received from the Air Force? Were they surprised at some of the findings? But what was the reaction I guess?

Terry Stentz: I think the Air Force's reaction was very professional. Everything we did was very well received and the things we confirm they were very happy with and it confirmed what they thought they knew. And things that we pointed out that could stand some continuous improvement, like any system, were also very much appreciated. We totally enjoyed working with the Air Force. We think in the long run the engineering college has a vital role in helping solve military problems. And we want to continue and we think it was very positive and my impression from everybody in the Air Force that this was worth doing, and that they would rely on us again to help them. It's nice to have Offutt here have that connection.

Karl Vogel: You both had mentioned that you're trained in public health.

Terry Stentz: I'm a certified professional ergonomist. It's a fairly rigorous process. For over a period of years, you have to have at least one graduate degree in this area. Most of us are engineers, some are psychologists. And there's two eight hour exams like PE either pass or you don't. I've been doing this for almost 30 years now.

Kelli Herstein: And I met Terry through my studies in industrial engineering. I met him while I was studying for my master's degree. And he's really been a tremendous mentor for me, got me interested in public health and I'm now studying so that I can be a certified professional ergonomist. Which is quite the journey. It's gonna take me several years to get there. But without his leadership I never...

Terry Stentz: Mentoring, mentoring, mentoring.

Karl Vogel: That's one of the key things here. But for students who are interested in engineering, what would be the advantages of going into a public health field for them as engineers?

Kelli Herstein: Because we're always going to need engineering and we're always going to need public health. The problems just keep growing, and we solve one problem and a new problem pops up again. And it's new and exciting every day. And you get to really see the lives that you're touching. This engineering and public health both save lives.

Terry Stentz: Everything by design. And everything by performance of design is what this is all about. And in public health, we're looking at every human in every natural environment situation you could possibly be in. And I think sometimes engineers forget that everything we do affects people and the environment and so working with an interdisciplinary team helps us produce better designs and better performance. And certainly in all areas of public health need engineering input. And we need their input, too. We look forward to a long relationship with UNMC.

Kelli Herstein: And we love working with students. If there's students that are interested in public health and how engineering applies to public health, they should come talk to us.

Terry Stentz: We'll help them. The one's that we've helped get into this College of Public Health, primarily are from biological systems engineering. But the other engineering disciplines could do this, too. And if there are any students who want to know about this or how to do it, we are the ones that can show them how we did it. And I think the outcomes would be very good. We have an MPH degree graduate, Corey Sennic from Biological Systems Engineering, who is now a Regional VA Hospital Director as a certified industrial hygienist in California. She was in Omaha, and she did so well she got promoted. So there's engineers in the in the VA hospital system.

Karl Vogel: It's awesome. And now as far as this project goes, what's the future worse? Where's this headed from here?

Terry Stentz: They know we're here. They know the group at UNMC is here. And all they have to do is pick up the phone and say we've got another project, we're ready to go. In the meantime, Kelly and I are working with environmental safety health, on the Offutt Air Force Base and safety and ergonomics problems as outreach. And we're just setting up a project now to get involved with them over the summer.

Kelli Herstein: And we just finished a project with them looking at lower back injuries and material handling.

Terry Stentz: Inside of aircraft, which is very strenuous. I've also had a couple of military students who finished their MPH at the UNMC College of Public Health and they are now on active duty doing these things. So we've been faculty advisors, degree program advisors, and mentors for the full time active duty military people who get the MPH degree like what we have and then go back to active duty and serve in that capacity. So the military is ramped up to want more of these things as well inside their active duty component.

Karl Vogel: Well, thank you, Kelly and Terry for coming by and talking about this and sharing the work that you're doing that can be life saving around the world, especially helping our Air Force. Thank you for the work that you've done. And thank you for coming in.

Kelli Herstein: Thank you for having us today.

Terry Stentz: Yes, thank you very much.

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