You should spend about 20 minutes on Questions 1–13, which are based on Reading Passage 1 below.
Drains Before Doctors
Edwin Chadwick was born in 1800 at Longsight, then a village outside Manchester, and his family moved to London while he was still a small boy. He trained as a lawyer and was called to the bar, but for some years he earned his living mainly by writing for newspapers and reviews. His energy and evident ability brought him to the attention of Jeremy Bentham, the philosopher and legal reformer, whose secretary he became and whose principle that institutions should be judged by their usefulness he adopted for life. It was this connection, rather than any medical training, that shaped the career which followed.
In 1832 Chadwick was appointed to the commission that inquired into the poor laws, and he helped to draft the report which led, two years later, to the Poor Law Amendment Act. He then became secretary to the new Poor Law Commission, the body responsible for putting the law into practice. Relief for the able-bodied was in most cases available only inside a workhouse, and it was Chadwick's task to collect information from the officials who ran them. He noticed that a large share of the people seeking help were not idle but ill, and that a single outbreak of fever could push several families at once into destitution.
When the government ordered an official inquiry into the causes of such illness, he sent out questionnaires to doctors, clergymen and local officials throughout Britain and assembled their replies into a single volume. The Report on the Sanitary Condition of the Labouring Population of Great Britain appeared in 1842. The commissioners, nervous of its conclusions, refused to put their names to it, and it was published under Chadwick's name alone; he had written almost all of it and chosen and arranged the evidence himself. What it described was a country in which houses were crowded together, streets were unpaved, drains were blocked, and refuse was left to rot in the open within a few metres of the doors.
Chadwick's explanation of these evils was mistaken in an important respect. Like most of his contemporaries he held that disease arose from the smell of decaying matter, a theory usually called miasma, and he rejected the view that epidemics were passed from person to person or carried in water. Yet his practical conclusion followed almost whatever the theory behind it. If filth caused disease, the remedy was to remove it: to lay sewers, to supply clean water, to pave streets and to cart refuse away. He called this programme the sanitary idea, and it became the slogan of a movement.
The report sold in large numbers, was debated in Parliament and made its author famous. Chadwick followed it with a further inquiry into the condition of town churchyards, where the dead had been buried in numbers far beyond what the ground could hold. That inquiry contributed to a royal commission on the health of towns. He then saw that the mortality figures gathered by the Registrar General's office could compare one district with another, and these comparisons gave his campaign a precision earlier reformers had lacked.
Cholera reached Britain in 1848, and the alarm it caused gave the government an opportunity to act. The Public Health Act of that year created a General Board of Health, of which Chadwick was one of the three members, and allowed towns to establish local boards of their own. The act was permissive rather than compulsory: a local board could be formed where the ratepayers petitioned for one, or where the death rate exceeded twenty-three in every thousand of the population. Even so, it was the first time Parliament had accepted in principle that the state had a duty to protect the health of its citizens.
Chadwick used his position to press his own engineering opinions on the towns. He wanted what he called arterial drainage, a single system in which narrow pipes of glazed earthenware carried both sewage and rainwater to the nearest river. The large brick sewers favoured by most engineers, he argued, were costly and unnecessary. His manner made enemies. He was impatient, sure of his own judgement and determined to keep decisions in London, and he quarrelled with engineers, with the water companies and with many local authorities he was supposed to advise.
In 1854 the Board of Health was reconstituted, its functions were handed to other bodies, and Chadwick was retired with a pension. The sewer network that London eventually built took a different form. After the summer of 1858, when the stench of the Thames drove members from the House of Commons, the engineer Joseph Bazalgette was commissioned to construct great brick sewers many miles in length. Chadwick never accepted that cholera was spread by water, and he lived long enough to see his own account of disease abandoned by the medical profession.
His influence outlasted his unpopularity. The campaign he had begun led in 1872 to a requirement that every local authority should appoint a medical officer of health. It also led to the consolidation of public health law in the Act of 1875, which set standards for drainage, housing and water supply that remained in force for decades. Chadwick was knighted in 1889, a year before his death, by which time the drains he had demanded had come to be taken for granted as an ordinary part of urban life.
You should spend about 20 minutes on Questions 14–26, which are based on Reading Passage 2 below.
Standing In for the Kidney
A healthy kidney is a filter of extraordinary capacity. The two organs, each about the size of a clenched fist, together receive roughly a fifth of the blood the heart pumps, and between them they clean the entire circulating volume many times a day. They remove urea, produced when the body breaks down protein, and creatinine, a waste product of muscle activity, along with surplus water and salts. They also help to regulate blood pressure, activate vitamin D and produce erythropoietin, the hormone that keeps up the supply of red cells. Dialysis is offered when this filtering capacity falls to a small fraction of normal, most often as a result of diabetes or long-standing high blood pressure, and waste products begin to accumulate in the blood.
Two techniques are in use. In peritoneal dialysis a fluid is run into the abdomen through a catheter and the patient's own peritoneal membrane does the work, often overnight at home. Haemodialysis, the more common treatment in most wealthy countries, takes blood out of the body and passes it through a machine. Repeated access to the bloodstream is needed, and the usual solution is a fistula: a surgeon joins an artery to a nearby vein, generally in the forearm, so that the vein enlarges and its wall thickens until it can carry a flow large enough for the machine. A synthetic graft, or a line placed in a large vein in the neck, is used when a fistula is not possible.
The centre of the circuit is the dialyser, a plastic cylinder some twenty to thirty centimetres long that contains thousands of hollow fibres, each finer than a human hair. Blood is pumped through the inside of the fibres while a fluid called dialysate flows around their outsides within the cylinder. The wall of each fibre is a semipermeable membrane, pierced by pores small enough to hold back blood cells and large proteins but wide enough to let small molecules pass. Even so, a few hours of treatment several times a week cannot match organs that work without pause, which is one reason why dialysis never fully reproduces their work.
Most of the waste is removed by diffusion. Blood arriving at the dialyser is heavy with urea, while the dialysate contains none, and the resulting difference in concentration drives urea and other small molecules across the membrane. The dialysate is not pure water: its content of sodium, calcium, bicarbonate and other substances is set close to that of normal blood plasma so that useful material is not stripped from the patient, while the concentration of potassium is adjusted to draw off any excess. Blood and dialysate flow in opposite directions, which maintains a concentration difference along the whole length of the fibres.
Water is removed in a separate step. Pumps on the dialysate side create a pressure difference across the membrane, so that fluid is pushed out of the blood; the process is called ultrafiltration, and the machine is programmed to take off exactly the amount the patient has gained since the previous session. Remove it too quickly and the patient's blood pressure falls, with cramps, nausea and dizziness; remove too little and fluid collects in the lungs. Much of the skill of dialysis nursing lies in judging that balance for an individual.
The rest of the machine exists to keep this exchange safe. A roller pump squeezes the blood tubing and controls the flow, while pressure monitors on the arterial and venous lines detect kinks or a needle that has moved. An air trap on the return line allows bubbles to rise and be held back, and a detector stops the pump if any escape. A syringe pump delivers heparin, a drug that prevents clotting in the tubing. On the other side, the proportioning system mixes purified water with concentrated salts to make dialysate, and monitors check its temperature and conductivity. The water itself must be exceptionally pure, since a patient may be exposed to several hundred litres a week, and it is usually treated by reverse osmosis before use.
A typical patient attends a hospital or clinic three times a week for about four hours. Between sessions there are limits on how much fluid may be drunk and on foods rich in potassium and phosphate. Dialysis is not a cure. Small waste molecules are cleared efficiently, but larger ones accumulate over years and can damage joints and nerves, and most patients develop thickening of the heart and arteries. In wealthy countries the life expectancy of a person on long-term dialysis remains substantially shorter than that of the general population of the same age.
Research has therefore concentrated on doing more with the same hours. Haemodiafiltration, in which a large volume of fluid is filtered off and replaced, clears middle-sized molecules more effectively than standard treatment, though whether this extends life is still debated. Newer membranes are smoother and less likely to provoke inflammation. Engineers have built a wearable artificial kidney, a belt-mounted device intended to be worn continuously, and a bioartificial implant that combines silicon membranes with living kidney cells has been tested in animals; neither is close to routine use. For the moment a successful transplant remains the best treatment, but the supply of organs falls far short of demand.
You should spend about 20 minutes on Questions 27–40, which are based on Reading Passage 3 below.
Who Should Care for Whom?
The ethics of recruiting nurses from poorer countries
Few industries depend as heavily on the movement of people as health care. Wealthy countries are living through a demographic transition that raises demand for nursing almost every year: their populations are older, more patients live with several long-term conditions at once, and a large cohort of experienced nurses is approaching retirement. The World Health Organization has estimated a global shortfall of several million nurses, concentrated in low- and middle-income countries but felt in rich ones too. Faced with vacancies they cannot fill from their own populations, hospitals in Britain, the United States, Canada, Australia and the Gulf states advertise abroad.
The result is a well-worn set of routes. Nurses move from the Philippines, India, Nigeria, Ghana, Zimbabwe, Jamaica and South Africa towards a handful of destinations, and in some years a majority of the nurses joining the register in the United Kingdom qualified overseas. The reasons they give are rarely mysterious. Pay is several times higher, equipment and drugs are available, staffing levels are safer, and there are opportunities for specialisation and promotion that their home systems cannot offer. Most also send money home, and those transfers support not only their own families but, in some countries, a measurable share of the national economy.
The cost to the countries they leave is equally plain. Training a nurse is expensive, and it is paid for by taxpayers in countries far poorer than the ones that eventually employ them. The loss falls hardest on rural clinics and public hospitals, where posts may stay empty for years, and it is greatest in the very countries whose health systems are weakest. In 2010 the World Health Assembly adopted a code of practice on the international recruitment of health personnel, but the code is voluntary, has no means of enforcement and depends on the goodwill of the governments that signed it. Britain's health service, for its part, maintained for years a list of developing countries from which it said it would not actively recruit, though the list was quietly revised more than once.
It does not follow that the nurses themselves deserve blame. A trained professional who moves to another country to earn more, work in safer conditions and educate their children is doing what most people would do, and the right to leave one's country is not usually treated as conditional on the needs of the state. The shortage at home is created, in the first place, by governments that have underpaid health workers, allowed hospitals to decay and failed to train enough of their own staff. A policy that trapped nurses in poorly paid posts would not produce good care; it would produce resentful staff and, eventually, fewer of them.
The obvious answer for rich countries is to train more of their own. It is also harder than it sounds. A nurse cannot be produced in a year: training places must be funded, teachers found and clinical placements arranged, and the expansion has to be planned a decade ahead. Several wealthy countries cut their own training places in the 1990s and 2000s on the assumption that international recruitment would fill the gap, and the shortfall that resulted is now being repaired slowly and at considerable expense. Even with generous expansion, ageing populations mean that some reliance on internationally trained staff is likely to continue.
The reasonable response, then, lies between the two extremes. Recruiting countries can agree not to target countries whose health systems are critically short of staff; they can sign bilateral agreements with the countries they do recruit from; and they can contribute to the cost of the training that produced the staff they employ. They can also fund retention in those countries, through better pay, safer workplaces and equipment that works, and make it easier for nurses who wish to return to do so without losing their pensions or their professional standing. None of this is charity. It is payment for a resource that was not created at the employer's expense.
Behind the argument lies a larger question about inequality. Health workers move along the same channels as other skilled professionals, from poorer economies to richer ones, and the countries that receive them are the ones that can most easily afford to train their own. The gains are not one-sided: remittances can exceed what a nurse would have earned at home, returning migrants bring skills and contacts, and diaspora networks can support training and investment. But it is difficult to describe as fair a system in which a country spends a substantial part of its health budget educating staff who then care for patients in a country far richer than its own.
A ban would be neither just nor workable. Nurses cannot be prevented from leaving, and attempts to stop them would punish individuals for a failure of policy. What is defensible is managed migration: transparent rules, enforceable agreements, money for training and retention where it is most needed, and a serious effort by wealthy countries to staff their own wards. That settlement has to be made by governments, because it is governments that decide how many nurses are trained and how well they are paid. Blaming the nurse who boards the plane is easier, and achieves nothing.
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