There is no evolutionary precedent for the limits of survival we are now probing. By the time we’re supporting multiple organ systems on an intensive-care unit in the wake of major trauma, we’ve left evolution far behind. Out of those extremes, we depend not on our physiology but upon state-of-the-art systems of life support and the speed with which they can be brought to bear. The idea that, in the event of major accident, a team might literally drop out of the sky, scoop you up from the road, and propel you within minutes to a hospital is a construct of modern medicine that has existed only in recent decades. The edge of life, in that respect, has never been more heavily invested in.

 

This book is about the limits of our bodies in extreme conditions. Tangled with the history of medicine is the history of overcoming war, deadly contagions and exploration. Technology has allowed us, mostly in the past 150 years, to explore the frozen wastelands of the poles, the deep sea, and space. Our physiology is such that we can only last short periods of time in these conditions without succumbing to the elements.

Each chapter covers an area of health and details the circumstances in which innovation took place. From Sir Walter Scott’s frigid death in Antarctica in 1912 to reviving a clinically dead skier in the Alps nearly a century later; to plastic surgery repairing critically burnt fighter pilots disfigured faces in the World Wars; to the prospect of open heart surgery (another innovation with its root in the World Wars); to deep sea diving safely without being crushed by the pressure; this is the story of humanity’s fight to extend life in the most extreme circumstances.

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Highlights

Robert Falcon Scott’s life is a property distributed across the many trillions of cells that comprise his body. Like all human beings, he exists in a state of tension. By that I mean simply that nature seeks equipoise: It would like, as far as possible, for all things to be as equal as they can be.

It has taken me most of my medical career to finally appreciate the tiny processes that enable biological systems to store and release energy. These biochemical events individually appear to bear little relation to the wonder of life, when in fact collectively they are life; they are everything we do, everything we are.

As Scott’s core temperature drops, the pumps that move ions across his cell membranes are grinding slowing but surely to a halt. The process is inexorable. In the absence of energy, borrowed from the fuel of food and burned in the fire of the oxygen that we breathe, the pumps wind down and eventually stop. The ions begin to assume equal concentrations on either side of the cell membranes. This simple symmetry is how death begins.

Death results from the failure of the chemical processes that drive our cellular machinery.

Like all living beings, we fight against the laws that govern inanimate objects in an effort to avoid equilibrium with the physical world. Through the act of living, we maintain a level of complexity otherwise unknown in the universe: the ability to grow, to adapt, to reproduce, and as humans, the capacity for sentience and self-awareness. As fascinating and enigmatic as neutron stars and supernovas might seem, your brain is more complicated and more impenetrable to science than either. What makes us different, what sets us apart from the inanimate matter about us, is our ability to defy entropy, to avoid the thermodynamic reorganization, that would see us reduced to a simpler, lifeless state.

Evolution did not prepare us for life at the extremes. Only engineering and technology allow us to cheat our environment and our biological fate–and then only temporarily.

We do not climb mountains, traipse to polar ice caps, split atoms, or unravel genomes simply because “they are there” but because we know that it is within the unanticipated fruits of exploration that our improved survival lies.

In the United States more than one hundred thousand people are currently waiting for an organ transplant. The list is growing quickly; on average a new name is added every twelve minutes and demand outstrips supply. Each day in the United States eighteen people die waiting for an organ transplant.

The beating heart does not simply expand and contract. To witness it in life is to understand surgeons’ traditional reluctance to interfere. There is an element of torsion in the way that it moves–waves spreading across its muscle from base to apex. Even in health, its cadence constantly changes, accelerating and slowing periodically but with a clear, intrinsic, and vital rhythm. It exhibits a physical dynamism like no other organ in the human body, and thus it is inescapably the engine of life, even as it lies on the table before you.

Within a year of the end of World War II, techniques in cardiac surgery had begun to advance all over the world. This was more than simple coincidence. Advances in the field of anesthesia, radiology, blood transfusion, and antibiotic therapy combined with the catalyst of war to usher the age of cardiac surgery into existence.

The contribution of these advances is often understated, as though they were not entirely essential to the establishment of elective cardiac surgery. History had not simply waited for a surgeon bold enough to break with convention or one with sufficiently gifted hands. The annals of surgery are, after all, replete with such individuals. It had been waiting instead for a means by which medicine might protect the brittle physiology of those with diseased or injured hearts from the added insult of surgery.

In the worst situations, the trick is not to think too hard. It’s best to stay focused on the one task at a time and to make that task as simple as possible. For fast-moving situations, there are protocols that can be unpacked and delivered almost reflexively. While those achieve many things, one of their most important functions is to stop you–struggling in the midst of events that words could never adequately describe–from grinding to a halt.

In the face of massive hemorrhage, injured blood vessels spasm and shut themselves off to prevent further loss. Elsewhere, vessels in the extremities constrict, forcing blood back toward the central, vital organs, temporarily depriving less important tissues but returning more blood to the heart. This reflexive recoil of peripheral capillaries near the surface of the skin is partly what accounts for the pale appearance of trauma victims.

There is no evolutionary precedent for the limits of survival we are now probing. By the time we’re supporting multiple organ systems on an intensive-care unit in the wake of major trauma, we’ve left evolution far behind. Out of those extremes, we depend not on our physiology but upon state-of-the-art systems of life support and the speed with which they can be brought to bear. The idea that, in the event of major accident, a team might literally drop out of the sky, scoop you up from the road, and propel you within minutes to a hospital is a construct of modern medicine that has existed only in recent decades. The edge of life, in that respect, has never been more heavily invested in. Expectations of survival in the face of horrific physical injury and physiological insult have never been so high. All of this means that today, when faced with even the most extreme trauma, we are less willing to accept defeat.

The basis for the conscious process that triggers us to move a limb, speak a word, or register a thought remains elusive and likely will for some time to come. Consciousness is the last dark continent of life science. We are incapable of properly defining it, much less understanding how it works.

The cells of the nervous system are the oldest in your body. In contrast to almost every other cell type in the human body, they lack the ability to divide and self-replicate. Unlike skin cells, which enjoy a hefty turnover, if neurons become irretrievably damaged or die, they are not replaced.

Up until the middle of the twentieth century, medicine was mostly about the treatment of chronic illness: consumption, cancer, syphilis, arthritis, and the like. Short, severe illness was generally fatal. Survival was rarely attributable to heroic medical intervention. With the exception of a few genuine medical emergencies that could be solved with a knife, there was little that the art of medicine could put in the way of critical illness. The idea that medicine might be in the business of buying the patient time by supporting their vital organs against the onslaught of overwhelming disease was almost entirely alien. But Ibsen’s pioneering work in the field was to have far-reaching consequences. What Ibsen started by organizing patients into intensive wards of care during the Copenhagen polio epidemic came to underpin the frontiers of modern medicine. In time, intensive care allowed us to stretch and protect human physiology well past the previously accepted limits of survival–paving the way for more ambitious surgeries and more aggressive medical therapies.

That is all intensive care ever is: an extraordinary effort on the part of medicine to stretch human physiology well beyond its survival limits in the hope that the patient can stay alive until something changes for the better.

The Armstrong limit defines the height above which simple augmentation of physiology is no longer enough. Beyond this, human life depends entirely upon artificial life support for survival. That layer around Earth, just twelve miles high, represents the narrowest of slivers. If Earth were the size of a soccer ball, then the zone in which life exists unsupported would be thinner than a sheet of paper wrapped around its surface.

In short, most astronauts return from long-duration spaceflight–missions of more than six months–in a temporarily diminished state: sleep deprived, their cardiovascular system deconditioned, their muscles and bones weakened, and their hand-eye coordination impaired. As blissful as the experience of floating around might appear, it erodes the body’s ability to function when challenged again by the force of gravity.

The term spaceflight is something of a misnomer. Human-rated spacecraft don’t really fly through space. Their rocket motors fire for only a few brief minutes at the start of the journey, throwing the vehicle and its occupants toward their intended target, like a medieval ballista hurling a missile at the walls of a castle. The spacecraft have their own rocket motors and thrusters, but these are far less powerful than the launcher that set them on their way. Once they’re traveling, only subtle course corrections can be made. So astronauts on their way to their destination are engaged in an activity that might more accurately be described as spacefall.

The practice of elderly care at first felt very alien. As a former psychics student, I was always looking for a way to reduce the problems I faced on the wards to something simpler, for systems that would collapse neatly into a few lines of equation and a physiological principle. But here medicine was far less algorithmic. There were, you rapidly came to realize, no quick fixes or easy answers to the medical problems that accompanied advanced age.

On February 12, 1898, a gentleman by the name of Henry Lindfield became the first recorded fatality from an automobile accident when he lost control of his two-seater and smashed into a tree outside of Purley. He had been driving downhill at the heady rate of 17 miles an hour.

In retelling the story of twentieth-century medicine, we often superimpose a narrative of steady progress, when in truth physicians, surgeons, and scientists did little more than stumble ahead, as all explorers do, solving and creating problems as they went.

We advance in science, medicine, and exploration in fits and starts. There is no real plan–at least not one that anyone has ever stuck to for very long. We happen upon our discoveries largely by accident, making the most of them as and when they arise. We meet disaster in the same way. We explore simply because we must. And that is what makes us human.