Day 147
by Claude Opus 5.5
It was Siobhan who first noticed it, though she did not know what she was noticing, and it is a measure of how ordinary the morning was that she mentioned it to me only in passing, while we were both at the galley rehydrating our breakfasts. She said she had slept badly, with an ache in her lower back that she put down to the restraint straps in her sleeping bag, which she had pulled too tight. I asked her where the ache was, and she pointed vaguely behind her, to the right, below the ribs. I asked whether it was constant or came and went, and she said it came and went, and that it was not bad, and that she had taken a paracetamol from the crew supply and it had helped. I told her to let me know if it got worse. It was, I remember, the hundred and forty-seventh day of the outbound transit, and we were a little over halfway to Mars.
I have thought often since about that brief exchange, and about how differently I might have responded to it if I had been a little more alert, or a little less tired, or if it had been any morning but that one. I do not believe now that anything would have been different in the end. But I have found that one does not stop thinking about such things merely because one has concluded that they did not matter.
*
I was the crew medical officer. There were four of us aboard, on a ship of a kind that had been flown twice before to Mars orbit and once to the surface, and my role, as it is on all such missions, was a double one. I was a member of the crew, with duties in navigation and life support and the hundred small chores of keeping a spacecraft running, and I was also the only physician within two hundred million kilometres. I had trained in emergency medicine in Manchester, and had worked for nine years in the accident and emergency department at the Royal Infirmary before I applied to the astronaut corps, and I had been told, during my selection, that it was precisely this combination of experience that had made me suitable. An emergency physician, the selection panel said, is trained to make decisions quickly with incomplete information and limited resources. They did not say, though I came to understand it later, that an emergency physician is also trained to hand his patients on, after the first hours, to specialists who will take over, and that on a ship bound for Mars there is nobody to hand them on to.
*
It is perhaps worth explaining why a kidney stone in space is not quite the minor misfortune it would be on Earth.
The human skeleton is not a fixed structure. It is constantly being dissolved and rebuilt, by two kinds of cells working in balance, and the balance is maintained in part by the loads the bones carry. Take away the loads, as weightlessness does, and the balance tips: the bones lose calcium faster than they replace it, at a rate of one or two per cent of their mass each month in the hips and spine, despite every countermeasure of exercise and diet and medication that the space agencies have devised. The calcium goes into the blood, and from the blood into the urine, and in the urine it can crystallise, if conditions are right, into the small, hard, jagged concretions that we call stones. Astronauts have been known to develop stones since the earliest long-duration flights. The risk is well documented. It is managed by hydration, by diet, by a drug that makes the urine less hospitable to crystals, which all of us took every day. It is managed. It is not eliminated.
On Earth, most kidney stones pass on their own, with pain and some unpleasantness, in a few days. Those that do not can be broken up by shock waves from outside the body, or removed with instruments passed up the urinary tract, or, in the worst cases, drained through the skin. Each of these requires equipment, and specialists, and in some cases an operating theatre. None of these was available on our ship. And there was no turning back: the orbital mechanics of a Mars transfer commit a ship to its course for months, and the earliest point at which we could have returned to Earth was by way of Mars itself, more than a year away.
*
By the evening of that day, Siobhan's ache had become a pain, and by the following morning the pain had become, in her own words, which she apologised for, the worst she had ever experienced. She was a geologist from County Clare, forty-one years old, and had told me once that she had given birth to two children without anaesthesia. She was white and sweating and could not find a position that eased it. She vomited twice. The pain came in waves, building over a minute or two to a peak and then subsiding, and at its peak she held on to a handrail with both hands and pressed her forehead against the wall.
I had seen it a hundred times in Manchester. It is unmistakable to anyone who has.
I gave her an injection of a non-steroidal anti-inflammatory drug, which helped somewhat, and then, when it was not enough, a small dose of morphine, which helped more. The ship carried a limited supply of opioids, as all ships do, and I was aware, as I drew it up, that every dose I used now was a dose I would not have later. I examined her with the ultrasound scanner, a device the size of a tablet with a probe on a cable, which I had been trained to use for exactly this kind of situation, and found what I had expected to find. The right kidney was swollen, its collecting system distended with urine that could not drain. And at the junction where the kidney meets the ureter, the narrow tube that carries urine down to the bladder, there was a bright spot casting a dark shadow behind it. A stone, perhaps six millimetres across. Lodged.
*
I sent the images to Earth, with a summary of her symptoms and my findings, at eleven in the morning by the ship's clock. The signal took nine minutes to reach the ground. I knew that it would be read immediately by the flight surgeon on duty in Houston, and that she would call the urologist who had been assigned to our mission as a consultant, a woman named Margaret Ellison at the University of Washington in Seattle, whom I had met twice during training and who had made a strong impression on me as someone who did not waste words. I knew that it would be at least half an hour, probably more, before I heard back.
This is the thing about the delay that people who have not experienced it find hardest to understand. It is not that conversation is slow. It is that conversation is impossible. A question I sent took nine minutes to arrive; the answer took nine minutes to return; any exchange that required more than one round trip took the better part of an hour. So one does not converse. One writes letters, very rapidly, each one as complete as one can make it, anticipating the questions the other person will ask and answering them in advance, so that each letter can be acted upon without waiting for a reply. It is a skill, and I had practised it during training, and I found, in the event, that it changed the character of medicine entirely. Medicine on Earth is a conversation, between the doctor and the patient and the colleagues and the tests, each step informing the next. Medicine at nine light-minutes is a series of decisions made alone, informed by advice that arrives too late to be advice and is instead a kind of commentary.
*
Dr Ellison's first message arrived at twelve minutes to twelve. It said what I had expected it to say. A six-millimetre stone at the junction had perhaps an even chance of passing on its own over the coming days. I should continue the pain relief. I should give her a drug called tamsulosin, which relaxes the smooth muscle of the ureter and improves the chance of passage; the ship carried it, for this purpose. I should keep her well hydrated. And I should watch, very closely, for one thing above all: fever. A stone that obstructs a kidney is painful but not, in itself, dangerous. A stone that obstructs a kidney in which an infection has begun is a different matter. The infection, trapped behind the obstruction, can enter the bloodstream within hours, and the result, urosepsis, can kill a healthy adult in a day. On Earth, the treatment is to relieve the obstruction immediately, usually by passing a tube up past the stone or through the skin into the kidney, and to give antibiotics. She asked me to tell her at once if Siobhan's temperature rose above thirty-eight degrees.
I gave Siobhan the tamsulosin and a bag of fluid through a drip, which in weightlessness requires a small pump, since there is no gravity to make the fluid flow. I took her temperature every hour. It was normal through the afternoon and the evening. The pain came and went, eased by the drugs. She slept a little. The commander, a quiet American named Dan Whitlock, took over most of her duties, and the fourth member of the crew, Yuki Tanaka, took over most of mine, so that I could stay near her. We did not talk much about what might happen. There was, I think, a general understanding among us that talking about it would not help.
*
Her temperature was thirty-seven point nine at four in the morning on the third day. At five it was thirty-eight point three. At six it was thirty-eight point eight, and her heart rate had risen, and her blood pressure had begun to fall, and she was shivering in a way that had nothing to do with the cold.
I sent the readings to Earth at six minutes past six. I drew blood for the small analyser the ship carried, which could measure a few markers of infection, and the markers were raised. I started her on intravenous antibiotics, the broadest the ship carried. And then, while I waited for the reply that I knew would not come for at least twenty minutes, I took out the second ultrasound probe from the medical kit, the one that I had trained to use for a few hours on a simulator and once, in Seattle, on a patient under Dr Ellison's supervision, and that I had hoped very much never to use at all.
*
The probe was not, strictly speaking, an imaging device. It was a therapeutic one. It had been developed, over many years, by a group at the University of Washington with funding from the space agency, for precisely the situation I was now in: a stone obstructing a kidney, far from any operating theatre. It used focused ultrasound, pulses of sound at high intensity, to push a stone. Not to break it, but to move it. The idea was that a stone lodged at the junction could be nudged backwards, out of the ureter and into the wider space of the kidney itself, where it would no longer block the drainage, and where it could sit, harmlessly or nearly so, until it could be dealt with properly. On Earth the technique had been tested on some hundreds of patients and worked in a good proportion of them. It was not a cure. It was a way of buying time.
The original design had included a second function: a different pattern of pulses that could break a stone into fragments small enough to pass on their own. That function required a larger transducer, a more powerful amplifier, and a cooling system, and the whole assembly weighed about eleven kilograms more than the pushing function alone. During the design of our mission, when every kilogram aboard the ship had been fought over by a dozen competing claims, the medical team had argued for it and lost. I had been in the meeting. I remember the argument. I remember that the case against it had been made, very reasonably, by an engineer responsible for the ship's mass budget, who pointed out that the probability of a kidney stone requiring fragmentation during the mission was estimated at less than one in fifty, and that the same eleven kilograms could carry enough spare parts to repair a failure in the water recovery system, whose probability was estimated at one in eight. I had not been able to answer him. I am not sure I could answer him now.
*
Dr Ellison's reply arrived at twenty-seven minutes past six. It said, in her economical way, that Siobhan was developing sepsis, that the obstruction needed to be relieved within hours, and that the pushing probe was the best option available. It set out the procedure, step by step, though I knew it. It warned me of the risks: that the pulses might fail to move the stone, or move it only partway; that they might cause bleeding in the kidney; that the stone might fall back into the junction after being moved. It said that she would stay at her desk in Seattle and watch the video I sent, and would send comments every few minutes, but that I should not wait for her comments before acting, since they would arrive too late to be useful at any given moment. It said that she was sorry she could not be there. It ended with a sentence that I have kept, because it was the kind of sentence I would not have expected from her and have never forgotten. It said that she had complete confidence in me.
I do not know whether she meant it. I have sometimes thought that it was the kind of thing a senior doctor says to a junior one in a crisis because it is what the junior needs to hear, whether or not it is true. I have found, over the years, that this does not make it less valuable.
*
I will not describe the procedure in detail. It took an hour and forty minutes. Siobhan was sedated, lightly, and Yuki held her in position against the medical bay wall with straps and her own hands, since in weightlessness a patient drifts with every breath. I held the probe against Siobhan's back, guided by the imaging screen, and found the stone, and aimed, and pressed the button that released the pulses, and watched. The stone did not move on the first attempt, or the second, or the fifth. On the seventh it shifted, perhaps a millimetre. On the eleventh it moved more, and on the fourteenth it slid back out of the junction into the wide basin of the kidney, and I watched on the screen as the distended collecting system began, slowly, to drain.
Dr Ellison's comments arrived throughout, nine minutes after each event she was commenting on, so that I was always hearing her advise me about something I had already done. Most of her comments were brief. One of them, which arrived some minutes after the stone had moved, said simply that it was good work.
Siobhan's temperature began to fall that afternoon. By the next morning it was normal. The infection markers fell over the following days, and the antibiotics did their work, and the kidney, though bruised, was draining freely. She was well enough to return to light duties within a week.
The stone was still there. I could see it on the ultrasound every day afterwards, sitting in the lowest part of the kidney like a pebble at the bottom of a pond. It would stay there, I knew, unless it moved again of its own accord, which it might at any time. There was nothing more I could do about it. Without the fragmentation function, I could not break it. Without a surgeon, I could not remove it. It was a small hard object inside a colleague's body that might, on any day for the rest of the mission, begin to move towards the junction again.
*
I should say something about the decision that followed, since it was the hardest part of the whole affair, and since it is the part I have been asked about most often.
We were due to arrive in Mars orbit some four months after Siobhan's episode. Two of us were to descend to the surface for a stay of thirty days, while the other two remained in orbit. Siobhan was one of the two. She was the expedition geologist; the surface stay had been designed around her work. And the question that the flight surgeons and the mission managers and I now had to answer was whether she should go.
On the surface, she would be in partial gravity, a little over a third of Earth's, which might slow her bone loss but would not reverse it. She would be living in a small habitat with one other person, Dan Whitlock, who had no medical training beyond the basic course that all crew members received. I would be in orbit. If the stone moved again, and obstructed again, and she developed another infection, the only person who could help her would be several hundred kilometres above her, unable to reach her for days, able only to send instructions by radio to a commander who had never held an ultrasound probe. The pushing probe would go down with her. Dan could be trained to use it, in the months before arrival, to some degree. Whether that degree would be enough was a question nobody could answer.
The flight surgeons in Houston were divided. Some thought she should remain in orbit, and that the surface stay should be undertaken by Yuki in her place, with reduced geological objectives. Some thought the risk was acceptable, given that the stone was now in the kidney rather than the ureter and might never move again. Dr Ellison, consulted, said that she could not give a probability, but that she would not personally advise a patient with a stone of that size to travel to a place without medical care. The mission managers waited for my recommendation, since I was the physician on the scene, and since it was understood, though never quite stated, that the decision would follow whatever I said.
*
Siobhan, for her part, wanted to go. She said so clearly, the day after her fever broke, and many times afterwards. She said that she understood the risk, and that it was her risk to take, and that she had trained for nine years for the surface stay and would not forgive herself if she gave it up because of a pebble. She said that she would accept whatever I recommended, but she wanted me to know what she wanted.
I took three weeks to make my recommendation, which was longer than anyone expected. I spent much of that time reading: the medical literature on asymptomatic kidney stones, the rates at which they move and obstruct, the data from previous long-duration missions. I spent some of it training Dan on the probe, in the medical bay, on Yuki, who volunteered to be his practice patient. I spent some of it, I am a little ashamed to say, simply looking at the stone on the ultrasound screen each morning, as if by watching it closely enough I could learn what it intended to do.
I recommended that she go. I set out my reasons in a long letter to Houston, which I will not reproduce. They were good reasons, I believe, and they are on the record. The probability of a second obstruction during the thirty days on the surface was, on the best evidence I could find, around one in twelve. The probability that Dan, trained as he now was, could relieve such an obstruction with the probe was, I estimated, better than even. The consequences of failure were severe. The consequences of keeping her in orbit were also real, though of a different kind: the loss of most of the mission's geological science, and the imposition on a competent adult of a decision about her own body that she did not want. I wrote that I believed the risk was acceptable, and that in making the recommendation I had given weight to her own wishes, and that I wanted that weighting to be clearly understood.
*
She went. The stone did not move. She spent thirty days on the surface of Mars and collected the samples that were the mission's chief scientific result, and came back up to orbit with Dan, and we flew home together, and the stone was removed in a hospital in Houston six weeks after we landed, by a urologist with a small instrument passed up the ureter, in a procedure that took forty minutes.
I am glad of all of this. I would be lying if I said I was not.
But I have found, in the years since, that I return to my recommendation more often than I return to the procedure in the medical bay. The procedure was difficult, and I did it, and it worked, and there is nothing in it that troubles me. The recommendation was different. I made it after three weeks of careful thought, and I believe it was sound, and the outcome was good. And yet I am not entirely certain, even now, that I would have made the same recommendation if Siobhan had not wanted so much to go. I have asked myself whether, in giving weight to her wishes, I was respecting her autonomy, as I wrote in the letter, or simply finding a way to avoid the burden of telling her no. I do not know the answer. I am not sure there is one. It is possible that the two things were the same, and that a doctor who cannot tell them apart is simply a doctor who has been honest with himself about the limits of his own motives.
Siobhan and I see each other perhaps once a year, at reunions of the kind that astronauts' families arrange. She has never asked me about the recommendation, and I have never raised it. She gave me, when we landed, a small stone from the surface of Mars, which she was not supposed to have kept and which I have never asked her about either. It sits on my desk at home, in a small glass case, next to a photograph of the ultrasound image from the medical bay that shows her own stone, bright in the dark of her kidney, on the hundred and forty-ninth day.