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Noteworthy:
Reducing the Risks of Complexity |
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On October 30, 1935, at Wright Air Field in Dayton, Ohio, the U.S. Army Air Corps held a flight competition for airplane manufacturers vying to build its next-generation long-range bomber. It wasn't supposed to be much of a competition. In early evaluations, the Boeing Corporation's gleaming aluminum-alloy Model 299 had trounced the designs of Martin and Douglas. Boeing's plane could carry five times as many bombs as the Army had requested; it could fly faster than previous bombers, and almost twice as far. A Seattle newspaperman who had glimpsed the plane called it the "flying fortress," and the name stuck. The flight "competition," according to the military historian Phillip Meilinger, was regarded as a mere formality. The Army planned to order at least sixty-five of the aircraft. A small crowd of Army brass and manufacturing executives watched as the Model 299 test plane taxied onto the runway. It was sleek and impressive, with a hundred-and-three-foot wingspan and four engines jutting out from the wings, rather than the usual two. The plane roared down the tarmac, lifted off smoothly, and climbed sharply to three hundred feet. Then it stalled, turned on one wing, and crashed in a fiery explosion. Two of the five crew members died, including the pilot, Major Ployer P. Hill. An investigation revealed that nothing mechanical had gone wrong. The crash had been due to "pilot error," the report said. Substantially more complex than previous aircraft, the new plane required the pilot to attend to the four engines, a retractable landing gear, new wing flaps, electric trim tabs that needed adjustment to maintain control at different airspeeds, and constant-speed propellers whose pitch had to be regulated with hydraulic controls, among other features. While doing all this, Hill had forgotten to release a new locking mechanism on the elevator and rudder controls. The Boeing model was deemed, as a newspaper put it, "too much airplane for one man to fly." The Army Air Corps declared Douglas's smaller design the winner. Boeing nearly went bankrupt. Still, the Army purchased a few aircraft from Boeing as test planes, and some insiders remained convinced that the aircraft was flyable. So a group of test pilots got together and considered what to do. They could have required Model 299 pilots to undergo more training. But it was hard to imagine having more experience and expertise than Major Hill, who had been the U.S. Army Air Corps' chief of flight testing. Instead, they came up with an ingeniously simple approach: they created a pilot's checklist, with step-by-step checks for takeoff, flight, landing, and taxiing. Its mere existence indicated how far aeronautics had advanced. In the early years of flight, getting an aircraft into the air might have been nerve-racking, but it was hardly complex. Using a checklist for takeoff would no more have occurred to a pilot than to a driver backing a car out of the garage. But this new plane was too complicated to be left to the memory of any pilot, however expert. With the checklist in hand, the pilots went on to fly the Model 299 a total of 1.8 million miles without one accident. The Army ultimately ordered almost thirteen thousand of the aircraft, which it dubbed the B-17. And, because flying the behemoth was now possible, the Army gained a decisive air advantage in the Second World War which enabled its devastating bombing campaign across Nazi Germany. That's a story from 1935 and the birth of checklists as a way to reduce the risks of complexity. The heart of the original article is about applying a lesson from 1935 to Intensive Care Units today. I read the article as an endorsement for the wider use of checklists as a tool to deal with the complexities of information technology, but that's my bias. I also read it as an amazingly simple way to reduce the risks and costs of modern medicine. Medicine today has entered its B-17 phase. Substantial parts of what hospitals do-most notably, intensive care-are now too complex for clinicians to carry them out reliably from memory alone. ICU life support has become too much medicine for one person to fly. Yet it's far from obvious that something as simple as a checklist could be of much help in medical care. Sick people are phenomenally more various than airplanes. A study of forty-one thousand trauma patients-just trauma patients-found that they had 1,224 different injury-related diagnoses in 32,261 unique combinations for teams to attend to. That's like having 32,261 kinds of airplane to land. Mapping out the proper steps for each is not possible, and physicians have been skeptical that a piece of paper with a bunch of little boxes would improve matters much. In 2001, though, a critical-care specialist at Johns Hopkins Hospital named Peter Pronovost decided to give it a try. He didn't attempt to make the checklist cover everything; he designed it to tackle just one problem: tube or line infections. On a sheet of plain paper, he plotted out the six steps to take in order to avoid infections when putting a line in. These steps are no-brainers; they have been known and taught for years. So it seemed silly to make a checklist just for them. Still, Pronovost asked the nurses in his ICU to observe the doctors for a month as they put lines into patients, and record how often they completed each step. In more than a third of patients, they skipped at least one. The next month, he and his team persuaded the hospital administration to authorize nurses to stop doctors if they saw them skipping a step on the checklist. The new rule made it clear: if doctors didn't follow every step on the checklist, the nurses would have backup from the administration to intervene. Pronovost and his colleagues monitored what happened for more than two years. Only two line infections occurred during the entire period. They calculated that, in this one hospital, the checklist had prevented forty-three infections and eight deaths, and saved two million dollars in costs. Pronovost recruited some more colleagues, and they made some more checklists. The proportion of patients who didn't receive the recommended care dropped from seventy per cent to four per cent; the occurrence of pneumonias fell by a quarter; and twenty-one fewer patients died than in the previous year. The researchers found that simply having the doctors and nurses in the ICU make their own checklists for what they thought should be done each day improved the consistency of care to the point that, within a few weeks, the average length of patient stay in intensive care dropped by half. The checklists provided two main benefits. First, they helped with memory recall, especially with mundane matters that are easily overlooked in patients undergoing more drastic events. A second effect was to make explicit the minimum, expected steps in complex processes. Checklists established a higher standard of baseline performance. In 2003, the Michigan Health and Hospital Association asked Pronovost to try out three of his checklists in Michigan's ICUs. Pronovost had been canny when he started. In his first conversations with hospital administrators, he didn't order them to use the checklists. Instead, he asked them simply to gather data on their own infection rates. In early 2004, they found, the infection rates for ICU patients in Michigan hospitals were higher than the national average, and in some hospitals dramatically so. In December, 2006, the results were published in The New England Journal of Medicine. Within the first three months of the project, the infection rate in Michigan's ICUs decreased by sixty-six per cent. The typical ICU cut its quarterly infection rate to zero. Michigan's infection rates fell so low that its average ICU outperformed ninety per cent of ICUs nationwide. In the first eighteen months, the hospitals saved an estimated hundred and seventy-five million dollars in costs and more than fifteen hundred lives. The successes have been sustained for almost four years-all because of a stupid little checklist. The still limited response to Pronovost's work may be easy to explain, but it is hard to justify. If someone found a new drug that could wipe out infections with anything remotely like the effectiveness of Pronovost's lists, there would be television ads with Robert Jarvik extolling its virtues, detail men offering free lunches to get doctors to make it part of their practice, government programs to research it, and competitors jumping in to make a newer, better version. That's what happened when manufacturers marketed central-line catheters coated with silver or other antimicrobials; they cost a third more, and reduced infections only slightly-and hospitals have spent tens of millions of dollars on them. But, with the checklist, what we have is Peter Pronovost trying to see if maybe, in the next year or two, hospitals in Rhode Island and New Jersey will give his idea a try. I asked him how much it would cost for him to do for the whole country what he did for Michigan. About two million dollars, he said, maybe three, mostly for the technical work of signing up hospitals to participate state by state and coordinating a database to track the results. He's already devised a plan to do it in all of Spain for less. "We could get ICU checklists in use throughout the United States within two years, if the country wanted it," he said. Just because the solution is simple and obvious doesn't mean it will be accepted. And adding tools to reduce risk doesn't mean that the staff in the ICU, or the flight crew, or the IT team doesn't have to be proficient. But the costs of failures in these and other complex activities are becoming so high that we need to explore and implement new ways to reduce the risks of complexity. The simpler and sooner the better. I've always enjoyed The New Yorker magazine, particularly the cartoons. This year Pat bought me a subscription and I am amazed at the content. This article is excerpted-with my comments-from an article titled The Checklist in the December 10, 2007 edition. You can subscribe to the New Yorker.
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