Human error:

1
Human error

• Epidemiology and Pathology

2
Institute of medicine report on medical errors

• New York study
• 30,000 patients in 51 hospitals
• Serious and adverse medical events in 3.7 -
  (1110)
• 13.6 - (151) who experienced adverse event died
  .
• Colorado / Utah study
• Random sample of 15,000 representative hospital
  discharges
• 2.9 (435)adverse events,
• 8.8 (38)of those died

3
Annual death rates in USA

• Deaths due to medical errors
• Highway accidents
• Breast cancer
• AIDS

• Between 44,000 and 98,000
• 43,458
• 42,297
• 16,516

4
Prevalence of errors in hospitals

• Personnel et al reviewed the medical records of
  30,121 patients admitted to 51 acute care
  hospitals in New York State in 1984. They
  reported that adverse eventsinjuries caused by
  medical management that prolonged admission or
  produced disability at the time of
  dischargeoccurred in 3.7 of admissions.
• A subsequent analysis of the same data found that
  69 of injuries were caused by errors

5
Prevalence and consequences in hospitals

• In a study of the quality of Australian health
  care, investigators reviewed the medical records
  of 14,179 patients admitted to 28 hospitals in
  New South Wales and South Australia in 1995. An
  adverse event occurred in 16.6(2353) of
  admissions, resulting in permanent disability in
  13.7(1942) of patients and death in 4.9(694)
  51 of adverse events were considered to have
  been preventable.

6
Aggressive case finding

• Observers on the general surgical units of a
  Chicago teaching hospital who recorded all
  "situations in which an inappropriate decision
  was made when, at the time, an appropriate
  alternative could have been chosen" found that
  45.8 of patients had an adverse event. 18 of
  these patients had a serious adverse event that
  is, one that produced at least temporary
  disability.

7
Aggressive case finding

• Donchin et al placed an observer at patients'
  bedsides to observe physicians in the
  medical-surgical intensive care unit of a
  university hospital in Israel. Clinicians made
  554 errors during 4 months, or 1.7 errors per
  patient per day.

8
Outpatient errors

• In both the Harvard and the Australian studies,
  about 9 of adverse events occurred in a
  physician's office, up to 3 at home, and as many
  as 2 in nursing homes. In the Australian study,
  about 25 of the adverse events occurring among
  outpatients caused permanent disability or death,
  and investigators judged it likely that more than
  2/3 could have been prevented

9
Asking physicians and patients

• Bhasale et al collected anonymous incident
  reports from Australian general practitioners of
  "an unintended event... that could have harmed or
  did harm a patient." Of 805 incidents involving
  drug treatment, diagnosis, and equipment, 27 had
  the potential to cause severe harm, and 76 were
  judged to have been preventable.

10
Asking physicians and patients

• Gandhi et al evaluated complications associated
  with medications among patients at 11 primary
  care sites in Boston. Of 2,258 patients who had
  had drugs prescribed, 18 reported having had a
  drug-related complication, such as
  gastrointestinal symptoms, sleep disturbance, or
  fatigue, in the previous year.

11
Necropsy findings

• In a retrospective study of 524 deaths occurring
  in 1990-1991 at a Spanish tertiary care hospital,
  more than half of the risk of death was accounted
  for by adverse events that resulted from clinical
  care. The number of misdiagnoses and major
  unexpected findings at necropsy has remained
  essentially unchanged for more than 40 years,
  prompting health care leaders to cite the falling
  rate of necropsy as an important impediment to
  ensuring the safety of patients.

12
Consequences of medical error

• In Bates et al's study of adverse drug events at
  2 teaching hospitals in Boston
• 1 of the events were fatal,
• 12 were life-threatening,
• 30 were serious,
• 57 were significant.
• Of the adverse events classified as
  life-threatening or serious, 42 were
  preventable.
• Errors resulting in preventable adverse events
  occurred most often during ordering (56) and
  administering (24).

13
Cost of medical errors

• Patients injured as a result of a medical error
  stay in a hospital longer and have higher
  hospital costs. At the hospital in Utah, adverse
  drug events caused complications in 2.4 of
  admissions, cost an average of 2,262 per
  patient, and lengthened the stay by 1.9 days
  compared with matched controls.

14
Cost of medical errors

• In the Harvard study of adverse drug events, the
  incremental cost associated with an event was
  2,595, and the length of stay was increased by
  2.2 days. Among preventable adverse drug events,
  however, the excess cost was 4,685, and the
  length of stay was increased by 4.6 days. The
  cost of adverse drug events for a 700-bed
  teaching hospital was estimated to be 5.6
  million a year

15
Cost of medical errors

• In Australia, medical error results in as many as
  18,000 unnecessary deaths, and more than 50,000
  patients become disabled each year. In the United
  States, medical error results in at least 44,000
  (and perhaps as many as 98,000) unnecessary
  deaths each year and 1 million excess injuries.

16
Cost of medical errors

• the cost of drug-related morbidity and mortality
  among outpatients in the United States (Johnson
  and Bootman)
• 116 million extra visits to a physician per year,
  
• 76 million additional prescriptions,
• 17 million emergency department visits,
• 8 million admissions to hospital,
• 3 million admissions to long-term care facilities
• 199,000 additional deaths.
• The total cost was estimated to be 76.6 billion,
  rivaling the aggregate cost of caring for
  patients who have diabetes.

17
Human error

• Pathology

18

• Physicians' Side

19
Physicians Who Make Errors

• Although anesthesiologists pioneered modern
  research into the safety of patients, no
  specialty is immune to error.
• Procedural mishaps are common in surgical
  specialties,
• Mistakes may be more common when a physician is
  inexperienced and when new techniques are
  introduced.
• Misread radiographs and pathology specimens,
  laboratory errors, and mistakes made in
  administering radiation therapy also threaten the
  safety of patients.

20
Physicians Who Make Errors

• Trainees often err.
• Wu et al surveyed medical house officers in 3
  training programs in internal medicine about
  their most serious mistake. Altogether, 45
  reported making at least 1 error, 31 of which
  resulted in a patient's death.
• Lesar et al found that more prescribing errors
  occurred among first-year postgraduate residents
  than among other physicians.
• Wilson et al found that more errors occurred in a
  pediatric intensive care unit when new physicians
  joined the rotation.

21
Errors in trainees

• The learning process is filled with error as the
  learner tries to develop and refine the
  knowledge, skills, and attitudes necessary to
  fulfill his or her new professional role.
• In many error-critical situations such as
  aviation, this learning process takes place in a
  protected environment such as a simulator to
  minimize risk to the public, the teacher, and the
  learners themselves.

22
Errors in trainees

• ONeal et al. found that Graduate Trainers were
  willing to report errors in a confidential
  reporting system, and that their self-reporting
  was as effective in identifying adverse medical
  events as medical chart audit.
• Denisco and Jacques have looked at the
  performances of GTs in relation to sleep
  deprivation.

23
Errors in trainees

• Duncan, in his observational study of GME, notes
  problems such as lack of supervision, excessive
  work hours leading to sleep deprivation, and
  inadequate formal educational programs.
• Feinstein raises issues of supervision by faculty
  as a significant issue that requires changes so
  that learners can better manage errors.

24

• Patients' Side

25
Risk Factors for Injury

• Patients older than 64 years, have a greater risk
  of serious injury from adverse events than
  younger patients.

26
Risk Factors for Injury

• Certain interventions signal that there is a high
  risk, such as cardiothoracic surgery, vascular
  surgery, and neurosurgery.
• The severity of a patient's underlying illnesses
  and the inherent hazards of certain procedures
  may increase the likelihood of poor outcomes.

27
Risk Factors for Injury

• Wilson et al found that a greater risk of death
  and a greater number of preventable adverse
  events were associated with patients with complex
  cases, illnesses requiring urgent care, and the
  use of interventions thought to be potentially
  lifesaving.

28
Risk Factors for Injury

• Medical errors are more common in emergency
  departments several factors are implicated
• the use of part-time physicians not trained in
  emergency care
• fluctuating demand for services, which results in
  uneven and sometimes abbreviated care
• the limited time available to arrive at a
  definitive diagnosis
• and the fact that emergency departments are the
  point of entry for acutely ill patients.

29
Risk Factors for Injury

• Time spent in hospitals is associated with risk
  of medical errors.
• Andrews et al reported that the likelihood of an
  adverse event increased by 6 for each day spent
  in a hospital

30
Risk Factors for Injury

• The intensity of care also affects the risk of
  injury. Among pediatric patients admitted to a
  British university hospital, drug errors were 7
  times more likely to occur in the intensive care
  unit than elsewhere

31
Cognitive vs. technical

• In the Australian study, cognitive errors, such
  as making an incorrect diagnosis or choosing the
  wrong medication, were more likely to have been
  preventable and more likely to result in
  permanent disability than technical errors.

32
Drug related errors

• In Bates et al's study of adverse drug events at
  2 teaching hospitals in Boston, errors resulting
  in preventable adverse events occurred most often
  during ordering (56) and administering (24).

33
Three main fields involved in human error

• Cognitive Science (also known as Cognitive
  Engineering) is itself a mix of different
  disciplines, including psychology, philosophy,
  neuroscience, and artificial intelligence.
  Cognitive scientists attempt to understand and
  model cognitive abilities such as perception,
  learning, language, memory, problem solving, etc.
  

34
Three main fields involved in human error

• 2. Human Factors or Ergonomics look at the
  specifics of human performance and how it can be
  improved. On the computer side, human factors
  engineers can help determine how to lay out the
  control panels of medical devices in order to
  maximize user performance.

35
Three main fields involved in human error

• 3. Systems Analysis attempts to model systems and
  organizations in order to understand its
  functions, including its relationships with other
  systems and its subsystems. Researchers try to
  understand how various components of a system can
  contribute to a problem.

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38
Mechanisms of Thought

• Rasmussen has provided a useful human behavioral
  taxonomy for the active errors.
• knowledge-based decision making
• Rule-based decision making
• Skill-based behavior

39
Skill-Based

• Skill is the ability to carry out a task
• skill-based cognitive processing and performance
  refers to actions that are automatic and easy due
  to an acquired skill.
• They usually happen quickly and without express
  effort on the part of the actor.
• These are unconscious actions that we don't need
  to explicitly "think about" in order to
  accomplish. Any decisions are usually automatic
  as well

40
Rules-based

• Rules-based processing involves matching the
  context and problem currently facing the actor.
  These rules are typically of the "if X then Y"
  form, and can be based on past experience,
  explicit instructions, and so forth.

41
Rules-based

• For example, if you want to treat hypocalcaemia,
  you normally give the patient calcium gluconate
  (an automatic skill). If the hypocalcaemia does
  not respond, however, you start to go down your
  list of reasons why it didn't works.
• Think about hypomagnesaemia,
• Think about hypoalbominaemia,

42
Knowledge-based

• If rules-based processing doesn't solve the
  problem, we fall back on knowledge-based
  processing (we tend to prefer rules-based
  solutions since they require less cognitive
  effort on our part).

43
Knowledge-based

• This is what happens when we are truly faced with
  novel or unfamiliar situations, or where
  low-level rules aren't appropriate (e.g. making
  strategic decisions, or establishing a medical
  diagnosis). In general, this kind of processing
  involves the processing of symbolic information.
• What about a refractory hypocalcaemia and
  hepatomegaly

44
Knowledge-based

• As with rule-based processing, knowledge-based
  processing is a conscious process. It refers to
  what we typically think of as "analytic thought"
  the process and analysis of personal subjective
  knowledge.

45
Mechanisms of Thought
46
Factors affecting thoughts and actions
Action
47
Human Error in Medicine

• Diagnostic Process Failure to employ indicated
  tests Misreading lab results Failure to act on
  the results of monitoring or testing.
• Treatment Technical error in performance Error
  in preparation the treatment (e.g. dosage)
  Delayed treatment or inappropriate care.
• Preventive (failure to provide prophylactic
  treatment) Inadequate monitoring, Inadequate
  follow-up of treatment.
• Other Failure to communicate Equipment failure
  Situated environments (OR and ICU)