Flying Fortresses and Medical Checklists: How a World War II era bomber can save patient lives today

Flying Fortresses and Medical Checklists: How a World War II era bomber can save patient lives today

            Paradoxically, while the patient safety movement has been increasingly embraced by Ob/Gyns, our efforts to create a safer environment grow more challenging each year as the healthcare industry becomes increasingly complex.  During her hospital stay, a patient is likely to interact with staff from numerous hospital departments in addition to her physician (e.g., nurses, medical assistants, physical, respiratory and occupational therapists, social worker, dieticians, diagnostic imaging staff, phlebotomists, pharmacists not to mention, admitting personnel and ward clerks).  Medical imaging increasingly provides us with increasingly detailed but often irrelevant data. The result is a veritable deluge of records and documentation with little time for one person to sort through it all to obtain a global view of the patient’s status.  Worse, even when such a global view can be obtained, testing and treatment algorithms change frequently based as on the results of latest clinical trials, and about 25,000 controlled clinical trials are published each year (1).   Thus, we are in the age of “information overload”.  To practice medicine in the 21st conscientiously means walking around in angst, wondering “Did I forget something?” and worse yet, “Did I forget something crucial?”
            Modern physicians are not the first to suffer such anxiety in high-stakes situations.  Imagine how the technicians at the Three Mile Island Nuclear Generating Station felt when the alarms started sounding 30 years ago.  In fact, imagine being a pilot in the U.S. Army Air Corps in 1935.  A year earlier, that service had requested designs for a bomber capable of carrying a significant bomb load at an altitude of 10,000 feet for 2000 miles (2).  The resulting design was the Boeing Model 299, which excelled in an early test flight.  However, development came to a screeching halt in October, 1935, when during a second test flight, the crew forgot to release the airplane's "gust lock," a device that held the bomber's movable control surfaces in place while the plane was parked on the ground (3).  After takeoff, the plane climbed, stalled, and headed nose-first in the ground.      An investigation concluded that the increased complexity of the new bomber had resulted in a pilot error, and the “talking heads” of the day wondered if it was “too much plane for one man to fly.”   The solution was remarkably simple - the pre-flight checklist; and Model 299 became the B-17 Flying Fortress which contributed significantly to our victory in World War II. But its greatest legacy may be its prompting of one of the first great human factor engineering improvements - the safety checklist.
As Atul Gawande has elegantly asserted “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” (4).  Checklists are now being adopted to guide staff through complex procedures that require systematic and comprehensive approaches.  The use of a checklist seems especially promising in surgery.  Haynes and colleagues recently published the impact of implementing a 19-item surgical safety checklist designed to improve team communication and consistency of care and, thus, reduce surgical complications and mortality (5).   Between October 2007 and September 2008, eight hospitals in eight cities participated in the WHO’s Safe Surgery Saves Lives program. Pre-intervention data were collected on clinical processes and outcomes from 3,733 consecutively enrolled patients 16 years of age or older undergoing non-cardiac surgery.  These findings were compared to 3,955 consecutively enrolled patients following introduction of the checklist. The primary end point was occurrence of complications, including death, during hospitalization and within the first 30 post-operative days.  The authors reported that mortality dropped from 1.5% before the checklist was introduced to 0.8% post-intervention (P=0.003).  Inpatient complications occurred in 11.0% of patients at baseline and in 7.0% after checklist introduction (P<0.001). 
Similar work is just beginning in obstetrics.  Clark and colleagues developed a checklist-based protocol for oxytocin administration (6).  Following a retrospective chart review of the last 100 patients receiving oxytocin before implementation of the checklist and the first 100 patients receiving oxytocin after protocol implementation, the authors reported that significantly fewer newborns with any index of adverse outcome in the post-checklist period (31 vs 18, P < 0.05).  System-wide implementation of this program was associated with a decline in the rate of primary cesarean delivery rate from 23.6% to 21.0%.  While the salutary effects of the checklist are difficult to isolate from those accruing use of a more conservative (lower dose and frequency of increase) oxytocin infusion strategy, the results are promising.  
Medical checklists are considered to be indispensible tools in condensing large quantities of knowledge in a concise fashion, to reduce errors of omission and commission and to maintain up to date best practices (7). They are particularly crucial in high acuity settings during the performance of low frequency, complex, procedures as found in intensive care settings, administration of anesthesia in operating rooms (and Labor and Birth) and providing acute emergency department care (7).   Recognizing that general anesthesia is now rarely given for cesarean delivery except in emergent situations, Hart and Owen compiled a list of 40 items they believed were crucial to preparing to administer general anesthesia using expert opinion (8). The resultant electronic checklist system with voice prompts was tested on 20 anesthesiologists using a high-fidelity anesthesia simulator.  The authors found that physicians omitted to check a median of 13 (range, 7-23) of the 40 items.  Among the omissions: not checking that the difficult intubation trolley was available and not confirming maternal left lateral tilt (8).  The authors rightly underscore the fallibility of human memory, especially under stress.  
Checklist use in intensive care settings have led to statistically significant improvements in compliance with various key best practices such as increased administration of aspirin for myocardial infarctions in the emergency department (21.4%; 95% CI; 7.3–32.7%) (9).  However, in Ob/Gyn this movement is still in its infancy and there are, as of yet, only a few studies like those cited above, showing efficacy.  Furthermore, a standard method to create reliable checklists is still lacking.  Hales et al., offer practical guidance to constructing checklists based on an exhaustive analysis of the published literature (7). They point out that there are multiple different types of checklists including laundry lists to verify availability of equipment, sequential lists to insure proper order and flow of tasks, and iterative checklists that that require repeated reviews to obtain valid results before proceeding in dynamic settings.   Table 1 presents some of their suggested steps in checklist development and a few of my own ideas.  Keys include utilization of pre-published guidelines, formation of expert panels and repeat pilot-testing of preliminary checklists.
Most of us recognized the fallibility of memory years ago, though maybe not consciously, the day we bought our first Washington Manual (or similar book) to slip into the pocket of our white lab coats.  Many of us have moved to fancier tools such that our tattered paper “pocket brains” have been replaced by PDAs.  But, our brains clearly need some help, be it in the form of reference tools or prompts in the form of checklists.  I believe that this is a tool in medicine whose time has come, and is here to stay and we have the B-17 to thank.

Table 1: Format for Creating Medical Checklists.
Determine need for checklist! Is it really mission critical, will it likely be cost-effective, can you get universal buy-in?
Identify the goal of, and audience for, the checklist.
Develop content from professional organization, state department of health and federal agency guidelines and best practices, from available published expert opinion or from your own local experts’ opinions. (Be sure to use UpToDate and Contemporary Ob/Gyn’s web site and other electronic sources to validate that these opinions are truly current). Be sure to involve physicians from other disciplines where appropriate (e.g., infectious disease, surgery, and anesthesiology)
Design should take into account practicality as well as completeness, particularly in acute care settings. Lists must be readability, concise, clear and in a logical order.  Avoid jargon and abbreviations must be avoided.
Pilot the checklist multiple times until all the “bugs” are worked out – balance completeness with practicality. Use realistic simulations for rare events.
Obtain any required approval (e.g., hospital medical board, state department of health, federal agency).
Conduct regular simulations for rarely used checklists involving acute care settings to maintain relevance and utility.
Regularly review and update checklists – and avoid checklist proliferation!

1.     Gluud C, Nikolova D. Likely country of origin in publications on randomised controlled trials and controlled clinical trials during the last 60 years.  Trials. 2007; 8:7 
2.     Goebel, Greg (2005). "Fortress In Development: Model 299". The Boeing B-17 Flying Fortress. Wikipedia, the free encyclopedia. Retrieved on March 23, 2009.
3.     Wikipedia, B-17 Flying Fortress, Retrieved March 24, 2009.
4.     Gawande, Atul (2007). The Checklist.  Retrieved March 24, 2009.
5.     Haynes AB, Weiser TG, Berry WR, Lipsitz SR, Breizat AH, Dellinger EP, Herbosa T, Joseph S, Kibatala PL, Lapitan MC, Merry AF, Moorthy K, Reznick RK, Taylor B, Gawande AA; Safe Surgery Saves Lives Study Group. A surgical safety checklist to reduce morbidity and mortality in a global population. N Engl J Med. 2009; 360:491-9.
6.     Clark S, Belfort M, Saade G, Hankins G, Miller D, Frye D, Meyers J. Implementation of a conservative checklist-based protocol for oxytocin administration: maternal and newborn outcomes.  Am J Obstet Gynecol. 2007; 197:480.e1-5.
7.     Hales B, Terblanche M, Fowler R, Sibbald W. Development of medical checklists for improved quality of patient care. Int J Qual Health Care. 2008; 20:22-30.
8.     Hart EM, Owen H. Errors and omissions in anesthesia: a pilot study using a pilot's checklist. Anesth Analg. 2005; 101:246-50.
9.     Wolff AM, Taylor SA, McCabe JF. Using checklists and reminders in clinical pathways to improve hospital inpatient care. Med J Aust. 2004; 181:428–31.


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