Surviving the Extremes: A Doctor's Journey to the Limits of Human Endurance (15 page)

Making matters even worse, the seawater sloshing around inside the lungs is “washing” the lining. Air sacs have an elastic coating on the inside so that, like any balloon, they can contract when the air goes out. But once that coating is rinsed away by seawater, the formerly springy balloons turn into flaccid bags. Water flows in but not out. The lungs become heavy and sodden, like a wet sponge. Those air sacs that are still dry are unable to push themselves open against the soggy mass. Without gas exchange, we lapse into unconsciousness, and when that happens, we lose our last defense against the sea—the gag reflex, which closes the trachea when there is food or liquid in the mouth. The gag reflex works only in conscious individuals. That’s the reason why patients having anesthesia can’t have anything to eat beforehand and why rock stars who overdose have been known to choke on their own vomit. An unconscious person taking in water can’t keep his trachea closed. The floodgates open, water pours in, and the lungs are finally overwhelmed.

Brain cells can endure only four minutes without oxygen before they start to die. This was not enough time for the six trapped teachers
and students on the
Albatross
to get to the surface. It was enough time, however, for Steve Callahan and for Lucien Schlitz and Catherine Plessz, who accomplished the first goal of any shipwreck victim—to not drown. The second is to get out of the water. When the
Titanic
sank, the survivors were the ones who made it into the rowboats. No one in the water lived, even though many wore life jackets and the water was actually warmer than the air. They died because water conducts heat away from the body thirty times faster than air. The water sucked the life out of them. Being on the water is far preferable to being in it, though those lucky enough to make it into a raft now confront the combined assault of sun and sea and get the chance to die of thirst, hunger, exposure, or isolation. Unless they are eaten by sharks first.

The ocean is not only the largest wilderness on the surface of the earth, it is the only one that moves. Everything that floats washes ashore sooner or later. Currents, tides, and winds ensure that anyone lost at sea, unless he or she is eaten, will eventually reach land or be spotted by a ship. If a human being can withstand the stresses of the ocean long enough, he or she will be rescued. Practicing extreme medicine on the high seas means sustaining a human body long enough so that when the life raft washes ashore, there is still life in it.

Before the whale, the storm, and the wind shear, the solo sailor, the romantic couple, and the high school students were comfortably settled on their boats. A few minutes later, they all found themselves adrift in life rafts—cold, wet, and in shock. The
Albatross
happened to sink in the Bahamas along a shipping route; the following day the surviving students and teachers were picked up by a freighter carrying a circus to Florida. When Lucien Schlitz and Catherine Plessz abandoned their boat, they were in the middle of the Mediterranean. A dozen ships passed them by before they were finally rescued two weeks later. Steve Callahan’s boat crashed into that whale off the Atlantic coast of Africa, however, leaving him adrift in the north equatorial current with the nearest landfall 1,800 miles away in the Caribbean.

Oceans cover three-quarters of the earth. The Atlantic is half the
size of the Pacific, but that nonetheless represents 34 million square miles. Callahan was floating on it in a 5½-foot-long raft. Military satellites can photograph the sea with enough resolution to pinpoint a life raft. Scanning just the Atlantic, however, would require one trillion photos. And since he did not have the time to send a distress radio signal, Callahan knew that no one would know where to look for him. It would be weeks before anyone even realized he was missing.

Though humans can survive only a few days without water, most people adrift on the ocean do not die of thirst. They don’t survive that long. They succumb to ignorance, fear, and despair—or to seasickness.
Nautical
and
nausea
share the same Greek root. Seasick sailors spend the first half of their voyage afraid they are going to die and the second half hoping they will. Seasickness, however, is no joke. For a castaway it can be fatal.

“Harvey staggered aft, doubled up in limp agony. His head swelled; sparks of fire danced before his eyes; his body seemed to lose weight. He was fainting from seasickness, and tilted over. A wave swung out and pulled him off and away. The great green closed over him.” Harvey is a character in Rudyard Kipling’s
Captains Courageous,
but his demise is no fiction.

Our bodies determine our orientation through three lines of information. Eyes seek out level surfaces to ascertain if we are tilted. Position sensors in bones and joints feel gravitational pressure, indicating our posture. Fluid-filled tubes in our inner ears change flow direction in response to acceleration, turning, and spinning. Taken together, they give us a good idea of our position and whether we’re moving—so long as all the information coincides. Even an experienced sailor can get seasick when he suddenly finds himself in intimate contact with the sky, the sea, and a raft, and all three are providing sensory input that doesn’t match. His eyes see an unmoving background of sky and horizon but a foreground of undulating waves. Those waves, in turn, are out of step with the signals from the body’s position sensors, which are experiencing the waves directly under the raft. Also, the raft is rolling, pitching, and veering, churning the inner ear fluid in three directions at once. Taken together, it’s enough to make you sick.

The nausea might be relieved by vomiting, but that creates more problems than it solves because it deprives the body of food, water, and electrolytes—minerals like sodium, potassium, and magnesium that are critical for nerves and other body tissues. Seasickness increases energy demand—vomiting takes strength—but decreases energy supply. The hapless victim becomes weak and dehydrated and, lacking the essential ingredients for nerve transmission, loses dexterity, judgment, and the will to live.

The first few days on a life raft are critical for survival. A lingering case of seasickness can mean the difference between life and death. Drugs such as scopolamine or Dramamine—if your raft happens to stock them—will provide some relief. If not, acupressure might help. Pressing two fingers into the center of your wrist stimulates the median nerve, the main nerve of the arm. This sends a steady impulse to the brain that interferes with the discordant signals it has been receiving and makes them easier to ignore. It is also a good idea to avoid tasks requiring a tight focus, such as stowing food, making the raft seaworthy, and taking navigational bearings, but that would mean avoiding precisely what is necessary to stay alive. Swimming provides an antidote to seasickness, though in the open ocean sharks are everywhere, and they are attracted to limbs dangling in water, especially if the water has already been chummed with food particles previously vomited overboard. Sometimes the treatment is far worse than the disease.

There are many other cures for seasickness: deep breathing, cassava beans, ice on the neck. I myself once found that a wet tea bag placed on the forehead was highly effective. What these treatments have in common is the placebo effect. There is no medical reason for any of these to work (at least not as far as we know), but if the sufferer believes it will work, it will lower anxiety. Reducing the fear that is the natural reaction of any castaway will allow the brain to control the conflicting signals. After a few days, the brain generally manages to sort out the information from the eyes, joints, and ears. It learns to rely mostly on the fluid in the inner ear, which functions like a carpenter’s level to keep the body in balance. The sailor regains his sea legs, provided that his body has not already been irreversibly debilitated—or washed overboard.

The ocean is home to 90 percent of life on earth, but for the 10 percent that can’t drink seawater, it’s a tormenting desert. Castaways like Steve Callahan have three to six days to find fresh water before they become too weak to drink and too delirious to remember why they wanted to. A body can last weeks without food but will dry up in nine to twelve days if it is not watered. Callahan was thirsty almost immediately. He had swallowed a lot of salt getting his supplies and equipment into his raft. He had enough food and water on board to last two weeks. However, he calculated that it would take about three months to make landfall in the Caribbean. He knew that fresh water would not be coming from the skies. His raft was being pushed across the Atlantic by a trade wind that blows from the Sahara. All the moisture had been baked out of the air, which has to cross half the ocean before it will pick up enough evaporation to give back rain. He couldn’t count on a gift from heaven.

What he could count on is what his species has always counted on for survival—applied technology: the innumerable inventions that have allowed humans to make their way into environments to which they cannot adapt physically. On board with Callahan was a solar still, a simple but delicate piece of equipment that turns saltwater into fresh. There were also some fishhooks, line, and a speargun. And there was the raft itself, a square of inflated rubber tubes partly covered by a domed canopy with just enough headroom for him to sit under. The thin floor sagged around his knees and rippled like a water bed whenever he moved, but the roof blocked the sun, and the sides kept out the sea. The still, the fishing gear, the raft, and the skills to use them were a legacy that creative minds had passed on to him. Now that he was completely isolated from the rest of his species, his survival as an individual would depend on how he used that legacy.

Without the raft, Callahan would have been eaten by a shark or drowned within a few hours; without the still he would die of thirst in a few days; without the fishing gear he would die of hunger in a few weeks. He was protected from a vast, powerful, natural ecosystem by a tiny, fragile, artificial environment, and he would survive only as long as he could preserve it.

The raft required daily upkeep. Air in the chambers expanded
during the day when it was heated by the sun. Automatic safety valves relieved the pressure on the walls. When the sun went down, the air cooled and contracted, and the sides of the raft sagged. Each chamber had to be topped up with a bellows pump every night, and more often when there were leaks. The source of a leak couldn’t always be found; even if identified, it might not be reachable, and even if reachable, it might not be patchable. Leaks under the water line brought the sea in from below; and a sudden incautious movement that enfolded a raft wall would bring a flood in over the top. Frequent, if not constant, bailing was necessary to prevent the raft from filling like a bathtub.

Sitting on the floor in a minimum amount of water, Callahan spent hours and days trying to set up his solar still. It turned out to be a finicky device. The still consisted of a plastic balloon with a seawater-soaked black cloth inside. Heat from the sun evaporates the water, leaving the salt behind. The warm water vapor rises and hits the top of the balloon, which is cooler than the superheated black cloth. Cool air can’t hold as much moisture as warm air, so the vapor condenses out on the inner surface of the balloon. It is the same phenomenon that occurs when body heat fogs your glasses. The vapor forms into droplets of fresh water that run down the inside of the balloon into a collecting chamber. The system does provide drinking water, though it works much better in theory than it does in a raft.

Callahan didn’t have the jaws or hands to catch fish, but with a fishhook and a speargun a human can become a predator
of
the sea. After twelve days, however, Callahan had succeeded only in distributing some of his own food as snacks to the fish. His reserves were meager enough without having to share. Since the shipwreck, he had eaten just 3 pounds of food. Only four more days of rations remained.

He wasn’t having any success with the speargun either. There is more to spearfishing than meets the eye. What actually does meet the eye is a beam of light conveying the image of a fish on it. That beam is deflected as it leaves the water, projecting the image farther away than the fish really is. Like objects in a rearview mirror, fish in the water are closer than they appear. This is a problem that has long since been solved by cormorants and Eskimos. As a cormorant tracks a fish from the air and then dives in after it, its eyes undergo an optical
correction that matches the refractive change in the water and keeps the fish in sharp focus. Not having the advantage of cormorant eyes, Eskimos solve the problem in a typically human way. They apply intelligence to experience and learn to throw their spears at empty water, aiming closer to the boat than where the fish appear to be. The Eskimos developed a way to compensate for their inadequate physical adaptation. Or, perhaps because they have the ability to develop skills, they had no need to develop specialized anatomy.

Having neither a cormorant’s eyes nor an Eskimo’s experience, Callahan was at a distinct disadvantage for open-water hunting. After many misses, he learned he should concentrate on the circle of water directly below his spear. Image deflection increases with distance. He realized that aiming straight down would minimize the distance so that the image and the fish would almost coincide. This was the kind of problem-solving under stress necessary for survival. Still, the fish wouldn’t cooperate. Few swam under the boat. Leaning motionless over the side, his speargun cocked, Callahan spent hours stock-still, as if posing for a statue of a warrior.

Yet the sea is not an implacable enemy. A raft casts a shadow. To the animal and plant life below, the raft represents an unmoving island, for it is carried along by the current at the same speed they are. The bottom of the raft quickly becomes colonized by barnacles, then by mollusks and weeds. Within a few days, it becomes a nursery for worms, tiny crabs, shrimp, and other crustaceans. Small fish gather beneath the raft and poke at the hors d’oeuvres on its undersurface. Larger fish, attracted to the collection of small fish, begin to follow along. Within a week or two, a marine ecosystem will develop—a food chain linked to the boat, literally within reach. Barnacles attach themselves so regularly to the bottom of any boat that sailors used to think they originated through spontaneous generation from the hull. Scraping them off is easy, and once they’re shelled, they’re edible. Combining them with the other denizens of the undersurface makes a sea mix that smells awful but doesn’t taste as bad as it looks. Nevertheless, for long-term survival at sea, a human has to catch fish.