Light, airy hospital rooms don’t just have psychological benefits (Image: Plainpicture/Arturimages/Werner Huthmacher)
IT WAS a warm summer’s night in 1968, at the height of the cold war. Two men stood on a lab roof at Porton Down, a UK ministry of defence site best known for its chemical and biological research programmes. On their minds was the grim prospect of biowarfare. If a bomb filled with deadly bacteria exploded above London, how long would the fallout remain dangerous?
To find out, microbiologists Henry Druett and K. R. May exposed microbes to air currents up on the roof. To stop the bacteria being blown away, the pair wound strands of spider silk around a comb, and gently dusted it with the common gut microbe, Escherichia coli.
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In little over 2 hours, nearly all the bacteria trapped in these hand-crafted webs were dead. Yet when kept in boxes of rooftop air at identical temperature and humidity, over half the microbes were still viable after that time. What was going on? Something in fresh air was killing bacteria, only to vanish when the air was enclosed.
The researchers carried out many further experiments, showing that the strength of the mystery substance, dubbed the open air factor, varied from one night to the next. As the spectre of biowarfare receded, though, interest in their research fell away.
But could it be time to blow the dust off the old reports? The need for new weapons against infection has never been greater, with a growing number of pathogens developing resistance to the antibiotics we have been using against them. So researchers are turning to the infection control methods of an earlier age. “It’s only now that patients are not getting better, because we’re running out of antibiotics, that we’re retracing our steps,” says Stephanie Dancer, a microbiologist at Hairmyres Hospital in East Kilbride, UK, who is trying to revive interest in these strategies.
The Porton Down researchers were not the first to notice the medical benefits of fresh air. In the mid-19th century, British soldiers in the Crimean war were less likely to die on the battlefield than from diseases they caught in the dirty field hospitals. Pioneering nurse Florence Nightingale famously slashed hospital death rates with a host of improvements – including throwing open the windows. On her return home, she applied those lessons in British hospitals. “It is necessary to renew the air round a sick person frequently, to carry off morbid effluvia from the lungs and skin,” she .
Clinics built to her light, airy design became known as Nightingale wards: long, narrow rooms with sash windows reaching up to the ceiling that allowed fresh air to flow through. This arrangement not only diluted airborne pathogens but also actively killed them, according to the Porton Down research.
There was another crucial aspect of Nightingale wards: their long sides were south-facing to let in plentiful sunlight. Soon the health benefits of sunshine became more widely recognised, particularly for people with tuberculosis, which at the time caused around one in five deaths in crowded cities.
Sunlight not only kills airborne bacteria and those on the skin, but also seems to kill TB microbes in the body by boosting production of vitamin D, which has effects on the immune system. By the turn of the last century “solar clinics” were in vogue, utilising fresh air and sunlight as part of TB treatment. Hospital beds were wheeled on to balconies or conservatories with special glazing that allowed ultraviolet light to pass through.
Eventually UV lamps were developed for use within hospitals, but fell out of favour as the risks of skin cancer and cataracts became apparent. Today they are generally used only to sterilise surgical equipment.
Miracle in a dish
Everything in medicine changed in the years after Alexander Fleming famously discovered the dish of bacteria that had gone mouldy during his holiday. Compared with the almost miraculous powers of penicillin and other antibiotics, sunlight and fresh air seemed irrelevant.
By the 1960s many doctors thought that infectious diseases would soon be vanquished. “It was one new antibiotic after the other,” says Dancer. “Open air factor was never going to kick-start major interest because when a patient got an infection, they got an antibiotic and they got better.”
The notion that fresh air and sunshine are somehow good for us has lingered in the public consciousness, yet hospitals have turned away from Nightingale’s principles, closing their windows and shutting out the sun. And once the oil crisis of the 1970s brought energy efficiency to the fore, open windows, which let precious heat escape, were phased out in favour of mechanical ventilation systems which recycle air and pass it through filters.
Today the need for energy efficiency is more pressing than ever, but hopes that infectious diseases might be conquered died long ago. New ones have been discovered at the rate of one every year for the past 30 years, and in the past decade we have faced down potential pandemics from SARS and bird flu.
What’s more, diseases that were easily treatable in the 1960s are returning in antibiotic-resistant forms, including TB, pneumonia and gonorrhoea. Hospitals themselves are one of the biggest sources of antibiotic-resistant diarrhoea and wound infections. In the UK, some 9 per cent of hospital patients catch a new infection during their stay.
To make matters worse, there is a shortage of new antibiotics. Since 1990, the number of large firms trying to develop such drugs has dropped from 18 to four. This year, England’s chief medical officer Sally Davies focused on the problem in her annual report, warning that we face the prospect of diseases that were previously easy to control becoming much more significant threats to our health.
Although the pipeline of classic antibiotics is running dry, there are various alternatives in the works. These include “quorum-blocking” drugs, which, rather than killing bacteria, merely stop them from mounting an attack; such drugs should be less likely to trigger resistance than conventional antibiotics. Another option is phage therapies, using viruses genetically engineered to destroy bacteria.
These strategies are some years away from reaching the clinic, though, and it would be unwise to bank on their success. In the meantime, perhaps we can prepare for the looming post-antibiotic era by taking some lessons from the pre-antibiotic age. No one is claiming that just drawing back the curtains and opening some windows can cure people who are already sick. But a few changes to hospital design could help prevent diseases spreading to those who are not yet infected.
After all, another old-fashioned disease prevention method is already paying dividends. Simply getting staff to wash their hands more is proving effective against the spread of superbugs MRSA and Clostridium difficile in the UK. MRSA rates in UK hospitals, for instance, have fallen by about 80 per cent since their peak in 2004. Hand-washing is not the only factor, but it seems an important one: the more alcohol hand rub a hospital uses, the .
Perhaps we would get similar benefits to infection control by resurrecting fresh air and sunshine, . “Hospitals of the future should be designed to allow windows to be opened and perhaps patients to be pushed outside in their beds,” she says.
Dancer is not alone in her quest. A team from Imperial College London has been working in the clinics of Lima, Peru, to see if traditional methods can reduce the spread of airborne TB, especially among people with HIV who are susceptible because of their weak immune systems. “The majority of TB transmission occurs where undiagnosed people mingle with susceptible ones,” says epidemiologist Rod Escombe. “Crowded waiting rooms are a hotspot, as are outpatient clinics and emergency wards.”
Lima has a mix of old-fashioned hospitals that rely on passive airflow, and modern ones with mechanical ventilation. By setting off carbon dioxide fire extinguishers within the hospitals and measuring how long it took for the gas to disperse, Escombe’s team showed that ventilation rates in the old hospitals were more than double those of the modern buildings.
As a result of that study, Lima’s hospital managers are already trying to add windows and skylights wherever possible. “Engineering a bit of a breeze is powerfully effective,” says Carlton Evans, an infectious diseases researcher at the city’s Cayetano Heredia University, who took part in the study.
Sometimes extra skylights just aren’t practical, though, so the team also investigated if a form of artificial sunlight might help. They installed a battery of old-fashioned UV lamps in a TB ward, angled toward the ceiling so that the upper half of the room was bathed in light without exposing patients to the rays.
A standard test for airborne TB was used: keeping pens of guinea pigs in air from UV-treated and untreated wards. The lamps cut the number of animals who developed signs of TB infection from 35 to 10 per cent, suggesting patients would have been protected too.
This research has attracted interest from countries around the world – especially in places with high rates of TB and HIV. It has been repeated in South Africa, where the drier air seems to enhance the effect of UV even further. The lamps have been installed in hospitals in Peru, as well as Russia and Brazil. St Mary’s Hospital in London also has one in the waiting room of its chest clinic. Stopping someone catching TB in the first place is always better than a long course of antibiotics. “We thought we had TB nailed,” says Escombe. “The resurgence has reignited interest in ways to prevent transmission.”
And there may be a way to make UV light safer so it can be used more widely in hospitals. UV is the portion of the spectrum with a wavelength of between 10 and 400 nanometres. At 207 nm, the UV is absorbed by protein molecules and therefore penetrates only a short way into human cells; it does not reach the DNA to cause mutations. Microbes, on the other hand, are so much smaller than human cells that they completely absorb the light and are killed (see diagram).
Now a lamp has been developed that emits only UV at 207 nm. Studies on cells grown in the lab have shown that this narrow band does not harm human skin tissue cultures yet .
The technology was originally designed for use during operations, to kill airborne bacteria that can settle in open wounds. “Bacteria are raining down on the wound during the entire surgery,” says David Brenner, who led the research at Columbia University in New York. Brenner even reckons all hospital light bulbs could be augmented to emit UV at this desirable wavelength.
If we can artificially reproduce sunlight, could we perhaps do the same thing for the benefits of fresh air? Attempts have been made to spruce up stuffy hospital air with a form of the open air factor, discovered 45 years ago. The Porton Down team eventually concluded their mystery germ killer was hydroxyl radicals. These short-lived molecules are constantly produced in the atmosphere through reactions between ozone and water, catalysed by airborne organic chemicals from plants.
For a short while a UK firm called Inov8 was marketing a portable device to hospitals that produced a steady stream of hydroxyl radicals, using ozone, water and replaceable cartridges of an organic catalyst. The firm showed that hydroxyl radicals oxidise biological molecules and kill bacteria, yet are harmless to people. The device was found to in hospitals, but the firm went out of business last year.
Perhaps it would be simpler to throw open the windows? Not without considering the possible drawbacks, says George Sharples, a microbiologist at Liverpool John Moores University in the UK. In fact, UK hospital regulations state that windows within reach of patients must open no wider than 10 centimetres so that people cannot fall out.
Open-air regime
Draughts can also blow equipment around, and there may be more insidious dangers in the breeze. “Hospitals today aren’t normally in remote areas – they’re in city centres,” Sharples says. Today’s patients would be exposed to traffic pollutants, or if the clinic were near a rubbish dump, fungal spores, which pose a risk to newborns, the elderly and others with weak immune systems.
New hospitals do tend to be more spacious, and have fewer hospital-acquired infections, but no one is quite sure why. “Is it more space between patients, is it better airflow?” wonders Mark Wilcox, head of microbiology and pathology at Leeds Teaching Hospitals in the UK. “Or is it a better work environment for staff, leading to better compliance with infection prevention practice?”
The World ÎçŇą¸ŁŔű1000ĽŻşĎ Organization is not so reticent, having published a urging all healthcare settings to use natural ventilation as far as possible, even referencing Florence Nightingale. In Mumbai, India, an old-style sanatorium is being refitted as a clinic for people with drug-resistant TB, making use of an open-air regime. “It’s well suited because of its high ceilings and open balconies,” says Escombe. “We’ve come full circle in hospital design.”
And it’s not just hospitals where getting more fresh air circulating could reduce the spread of disease: there are benefits anywhere that people live closely together. For instance, US soldiers stationed in the Saudi Arabian desert during the first Gulf war if they slept in air-conditioned barracks than if they bedded down in tents and warehouses. Another found that 35 per cent of those who slept in poorly ventilated dorm rooms got an infection over the course of a year, compared with 5 per cent in rooms that were better ventilated.
“US soldiers in the first Gulf war got more coughs and colds if they slept indoors than in tents”
In the future, we may well see architects, doctors and building managers working together to ensure that we live and work in environments that take account of our microbial companions. And in the meantime, perhaps we should take a leaf out of Nightingale’s book, and whenever possible let a breath of fresh air into our homes. “The first canon of nursing, the first essential to the patient, is to keep the air he breathes as pure as the external air, without chilling him,” she wrote. “Never be afraid of open windows.”
This article appeared in print under the headline “A breath of fresh air”
