After 20 years as a pediatric and neonatal intensive care unit nurse, Jennifer Culkin traded the ICU for the rear of an Agusta A1091 -- the helicopter that became her emergency room. With a nursing career that spans 30 years, she has witnessed and participated in both the beginning and end of life. She has not only cared for her ailing parents, but struggled with her own diagnosis with multiple sclerosis. She has lost friends, colleagues and patients and gained a lifetime's worth of experiences that she recounts in her memoir, "A Final Arc of Sky: A Memoir of Critical Care." In an interview with AOL Health, Culkin describes what challenges she faced, both physically and emotionally, as an emergency flight and critical care nurse.

AOL Health: How do you handle the pressure and stay calm when you're working?

Jennifer Culkin: There's a certain amount of compartmentalization that you have to do. You have to stay in the moment, you have to stay focused. You can't allow your feelings to get in the way of your effectiveness. You have to be the sort of person who can put feelings aside and focus. That's a skill I think you can also learn. I think people develop that over time. Knowledge helps you. The more experience you get, the more you learn. In nursing and in medicine it's a lifelong learning process.

AOL Health: Even with preparation and experience under your belt, are there ever moments where you get scared or frightened?

Culkin: Oh sure, absolutely. I think what happens for me is that when I start focusing on the first thing I need to do then it flows from there. You become more focused and you have less room for feeling nervous and fright. There's certainly some of that involved. Your heart rate definitely goes up at times.

You do have to react when something comes at you out of left field when you didn't expect it. It's like, oh sh**, and you have to refocus yourself. I think part of it is accepting that being afraid is part of it. It's normal and natural. Your feeling of initial fright is natural, but it's keying into what's the first thing you should do, and you become skilled at that over time, especially if you're faced with it every day. It becomes much more commonplace. It has to be something really extreme to freak you out.

AOL Health: Can you describe a time when a situation really did freak you out?

Culkin: For me the very scariest flight was the first chapter in the book, actually, "The Shadow We Cast." We were transporting a gentleman in his forties (younger than I was, and with several children at his bedside) with an aggressive cancer and upper gastrointestinal bleeding, flying him from a small rural hospital to a large referral center. He was awake, alert and talking to us when he suddenly lost consciousness, blood pressure and heart rate due to massive hemorrhage, most likely from a vessel in his esophagus. We were in the air, many, many minutes out from the receiving hospital. When he started spitting blood at the window of the helicopter, a second or two before he rolled back his eyes and passed out, I just had time to think "Oh, sh**…", a sentiment that sank all the way into my core. I felt the same stab of fear-related nausea that strikes people with normal jobs a second before they rear-end the car in front of them; a sick sweat broke out under my flight suit. After that, my partner and I had to run a full resuscitation and I think we both moved into a state of focus in which fear was still hovering under the surface but it played less of a role. We started with the first, obvious actions and everything flowed from there -- experience and training informed what we did. And I believe we did everything possible, but in this case it wasn't enough. I still regret that we couldn't make the difference for this relatively young father.

AOL Health: Have you ever had flying-related troubles or accidents?

Culkin: The other variety of fright is when things go wrong from the aviation standpoint. I've had friends and colleagues who lived through bird strikes that shattered the windscreen and splattered the interior of the helicopter with bird blood and remains, others who survived "hard landings" and crashes. Four friends have lost their lives in crashes. (Some of these incidents are in the final chapter of the book: "Out There in the Deep.") I was lucky that way -- my scariest moment was tiny by comparison.

We were on final approach to an accident scene. I could see the landing zone -- it was a well-lit nimbus in the dark, and large enough, but the area was so remote and heavily-wooded that there was nothing but a black void all around it. Our pilot asked us to watch for obstacles as we descended and all of a sudden I saw and blurted out that there were trees right under us! Our pilot was great; the helicopter halted its descent before the words were completely out of my mouth, hovered in place for a second, slid over to the right into the clear, and we proceeded to land and pick up an intoxicated gentleman with a head injury and a probable pelvic fracture.

AOL Health: Because your job comes with such a high stress level, did writing become a kind of therapy for you?

Culkin: Writing does help me clarify. It starts out that I have this feeling in my gut about it, and I don't really know what the component parts of it are. But when I start writing about it I can tease out exactly what was going on and the dynamics. It's personally helpful in that way to help get your head on straight. I do have a journal, and I've always been a writer in a way. I started writing about things that had caught in my memory for one reason or another -- people and cases that stuck with me. In the process of figuring out why they stuck with me a lot of the book happened.

AOL Health: In the book, you talk about managing your multiple sclerosis while continuing to work, which sometimes meant taking time off.

Culkin: It's a vast continuum, really. I've been lucky. I'm really on the mild side. I think that the drugs [I take] are helpful, and I've been on those since early 2002. I think that has helped me stay stable -- that and exercise. I did take two years off from work, which is kind of a big thing and hard for me to do. But I do think it helped me. I was so tired -- MS fatigue is terrible -- I was having a lot of flares. I was just in bad shape going into that and not having to work for two years set me up -- I really did improve quite a lot and was able to go back to work.

Fatigue is a huge thing, and the way I deal with that is I work part time. If I worked fulltime I would not do as well, frankly. Enough sleep helps. I know it sounds so basic, but we're chronically sleep-deprived in our culture, and I was, too, prior to having to deal with this. I do get really tired. It is a long day. Exercise and fitness helps me cope with it. I think if I were de-conditioned I probably couldn't do it. In spite of multiple sclerosis to maintain fitness has really made a difference for me.

AOL Health: When did you receive your initial diagnosis?

Culkin: 2001. But I had symptoms as long ago as 1988. I think my particular trajectory of MS was slow because it was 13 years from the time I first noticed symptoms that came and went until I actually got a diagnosis.

[Initial symptoms were] dizziness, numbness and tingling. Dizziness was really big. I would get this almost incapacitating fatigue. Memory loss. That was another thing in my 30s I was thinking, "Am I destined for Alzheimer's?" It was striking. I'd always had a good memory with quick information processing. All of a sudden I was noticing gaps in that, and that was frightening. I would say these things, and they would check my thyroid levels and those were fine, so it went on for awhile. Things would come and go. It's easy for you to say to yourself, "that was in my imagination."

AOL Health: Even as a nurse, you had no idea something was wrong?

Culkin: You would think I'd key in, but I was a pediatrics nurse and you don't see a lot of MS in the peds population. It was outside my area of expertise to clue into it. Also, there's very little MS in critical care. Things tend to happen slowly.

The thing that really triggered it was I developed blind spots in my left eye. It's optic neuritis, and it's a big red flag of MS. Forty percent of people with optic neuritis go on to develop MS.

AOL Health: As much as you can try to balance the disease, your job is both physically and emotionally demanding. Are there ever days where you just don't have the strength to go to work?

Culkin: If I have a flare-up and my symptoms are severe enough that it requires steroids I absolutely cannot work. What I get is three days of high-dose IV steroids, and I cannot work for about two weeks after that. I'm really dizzy. Some people don't have that much trouble with it, but I definitely cannot work in the wake of that. If I get a cold it can hit me a bit harder; it can bring out more of the neurologic symptoms.

AOL Health: What made you want to become an emergency flight and critical nurse?

Culkin: I was an emergency flight nurse for five years and currently back in critical care. I was always interested in medicine, and I was always drawn to the higher tech, sicker patients. That's what attracted me to it in the first place, and now it's been 30 years. I think what is perhaps a little unusual about me is that I've worked in all the critical care specialties. I was a pediatric and neonatal nurse for 20 years and a flight nurse for five years.

AOL Health: Caring for sick children in neonatal and pediatric seems like one of the more difficult specialties to cope with emotionally. What made you want to go into it and how did you handle the children and their families?

Culkin: Basically, you're there to do what you can to improve the situation. I loved working with kids and families. Kids are so resilient. They're very courageous in a lot of ways.

I like working in depth. I like the level of detail and the degree of understanding you have to have of complex issues when you work in critical care. I've enjoyed all the areas. With kids it was hard at times, but also when they improve they really improve. They can go on to live a long life, and that's very satisfying.

AOL Health: You've lost patients and friends, and you write about many of those experiences in your book. What are some of the moments that have stayed with you over the years?

Culkin: There are quite a few. It's interesting because in the process of writing the book, I rediscovered some. You know, you take care of so many people -- I've estimated it's between 5,000 and 10,000 people now -- and it's interesting what little details will trigger memories.

When you lose kids that stays with you. I don't know the end of the story of a lot of the people I've take care of. When they leave the critical care unit I don't know whether they did well or didn't do well, so that's a hard thing.

One of the stories in the book is about the first baby I ever took care of that died. She had a congenital anomaly that was incompatible with long-term life. It was just being new at it, being new in the environment and taking care of her. I really bonded to her [along] the way, so she has stuck with me all those years.

When you go out in the field and [patients have] had a cardiac arrest from trauma, they're very unlikely to survive even if we transport. And so you go out and you pick up these people, and you know it's a little bit of a fruitless exercise. That's kind of hard. There have been quite a bit of those over the years.

Now in my current environment I'm on the other end of the lifespan with adults, very, very many elderly adults. It is really great when an elderly adult comes in and you can get them back to their baseline so that they can get to go home and have another while to enjoy their lives.

AOL Health: Both of your parents have passed away, and in the book you talk about caring for them as they got older. As a nurse, you knew exactly what was going on with them medically. Was it difficult balancing being a daughter and a nurse?

Culkin: It puts you in an interesting position because you're usually the interface between the healthcare system and the parent for your family. That was kind of rocky in my parents' case, especially in my dad's case because he rejected a lot of the possible help he could get from the healthcare system. I had to work it out between him and me how much of that kind of help he wanted and at what point to back off. He has self determination. So that was very poignant and difficult, and at the same time I think we all did the best we could. It's a scramble for any family in that situation.

It was really trying to decide how much information and intervention my dad wanted or didn't want. It was particularly hard for me because had he been willing to go through more, I think he could possibly have had more good time, but he decided against it and you're the boss of your own ship in that way. He passed away in 2003.

My mom had been sick a long time, and for her it was [an issue] of [little] guidance from her. She was queasy about medical details. She was an example of someone who didn't want to know. I would try to have that discussion with her. How much intervention do you want? What constitutes quality of life to you? And she just wouldn't play ball. Then I found myself in the position of having to decide for her how much was enough. She passed away in June 2002.

AOL Health: What kind of hours do you work?

Culkin: For a flight nurse the shifts were 12 or 24 hours. I would show up at my helicopter base and be there for 24 hours and respond to calls when they came in. Between times there's a lot of work to do. Basically, you're your own purchasing department. You have to maintain your own equipment and all those support things that you work on in between calls. Sometimes you're just flying continually, especially in the summer here in Seattle. Summer is when people are out getting hurt. More people out, kids off school. The weather gets nicer; people are doing more sports. We call it trauma season.

AOL Health: How do you stay awake and alert for a 12-hour shift?

Culkin: Here's the payoff: If you do 12 [hours] then you have more days off a week. I actually love it, so instead of a five day work week, full-time is a three-day work week. Once you're in the groove, you just keep going.

AOL Health: How do you unwind when you get home to take yourself out of it?

Culkin: A shower helps. Writing was one of the things that did that for me, put me in the home. All these years, my sons are mostly grown, they're 20 and 23, but there was family life to reorient me.

Exercise is tremendous. It is really hard [to fit in]. That's one of the benefits of 12 [hour days], I don't [exercise] on days that I work. But all the other days I do and that is really a tremendous stress reliever. I think, overall, it really gives you more energy.

AOL Health: Does your job require you to be fit?

Culkin: Pretty fit. It's not a desk job. You're on your feet most of the day. You're running around. You're doing a lot of lifting. In the flight nurse environment, you're transporting patients and equipment. You have to pack things on your back and pack your equipment, pack your monitors. In the flight nurse environment it's a lot of bursts of energy. In the critical care environment it's really steady all day.

AOL Health: What else is required to become a flight nurse?

Culkin: In our program, you needed to be a very experienced nurse in either emergency care or critical care. Our program, which is somewhat unique, drew from pediatric specialties, too. So we had people onboard the aircraft who were experienced in critical care across the whole lifespan. It's a lot of training and experience. It's a steep learning curve initially. You have to really enjoy flying. It's very, very fascinating to go out to scene responses and to other hospitals and never exactly know what you're going to find. You need to come in and analyze the situation and do what's necessary to transport the person safely.

AOL Health: Do you have flight training?

Culkin: No. They are completely different departments.

AOL Health: How far does the helicopter fly out? Do you wait for a call?

Culkin: You wait for a call, and we were able to respond quickly. We were in the helicopter and in the air within 10 minutes. Sometimes weather is a factor. The range for our program was Western Washington. For helicopters it was about 200 miles. Sometimes we could go a little further than that. We also had a fixed-wing program that served Washington, Alaska, Montana and Idaho -- the WAMI states.

AOL Health: What's a typical day for an emergency flight nurse?

Culkin: It can be anything and everything. There are a lot of motor vehicle crashes. There are a lot of medical things like heart attacks. It really could have been absolutely everything on the spectrum, so you never knew quite what you were going to get. It was kind of fun to land on the freeway. It's fabulous flying over the traffic. That's always the high point. It was a very mixed bag. It was any age, any diagnosis. It was quite a lot of trauma, a lot of transporting from a hospital that's smaller with fewer services to a larger referral center.

AOL Health: What's the most stressful part about your job?

Culkin: Stress comes in different forms. The times where I had to put myself on the line the most were doing the flight nursing years. Basically because you're out there and it's you and your partner. You have some backup by phone or radio, but basically it's you, your partner and what's in your bag. So there's a particular what you know and what you can do. Your own personal knowledge base, resources -- those are spotlighted in that environment, but at the same time it was very rewarding. It was more stress but enjoyable and rewarding.

I think a lot of people could develop what it takes. I think it's really a learning process. I think you can grow into it. I probably couldn't have done it when I was 20, but there are skills, even emotional skills that help you handle it that you can learn.