Quality and safety


Quality in healthcare is the measure of the best possible outcomes in patient-centered care under the circumstances and with the resources available. Safety is a central dimension of quality in healthcare. It is the measure of standards that keep patients and healthcare workers free from hazards and harm due to error, management, or environmental factors and maintain the risk of harmful incidents as low as possible. The greatest risk factor in patient safety is human error, which can be defined as the accidental failure to perform an action as intended (e.g., misdosing the appropriate drug) or accidentally performing the incorrect action (e.g., prescribing the wrong drug). The deliberate deviation from standards, laws, or rules constitutes a healthcare violation. Human factors (e.g., poor communication, inappropriate performance), system factors (e.g., a mismatch between resources and workload), and external factors (e.g., legislation, weather, any factor beyond the control of the organization) all play a role in the development of safety risks. If an error has occurred, physicians must immediately inform the patient, disclose the nature of the error, and implement corrective measures to minimize patient harm.

Medical error analyses aim to identify, either retrospectively (root cause analysis) or prospectively (failure mode and effects analysis), risks in a healthcare system that may lead to hazards, errors, violations, and harm. Quality improvement (QI) in healthcare aims to implement system-based improvements in order to minimize the incidence and prevent the recurrence of medical errors.


  • Adverse event: any harm resulting from medical management rather than an underlying disease.
    • Can be preventable or nonpreventable
  • Near miss (close call): a medical error that could have resulted in an adverse event but did not, either incidentally or due to a timely intervention (e.g., a nurse identifies that a doctor's order is incorrect)
  • Medical error
    • Accidental failure to perform an action as intended (e.g., misdosing the appropriate drug) or accidentally performing the incorrect action (e.g., prescribing the wrong drug), which could potentially result in harm to the patient.
    • Individual error: medical error resulting from the failure of a single healthcare professional due to negligence
    • Systems error: medical error resulting from a series of actions and/or factors in treatment or diagnosis, from flaws in technical and organizational design and/or decision-making, and from failure to recognize and mitigate hazards and risks in the healthcare setting
    • See also section on “Medical error” below.
  • Medical malpractice
    • Negligence: failure to perform an action with the skill, care, and knowledge expected of a healthcare provider under reasonable circumstances
  • Safety culture: : a culture that promotes safety awareness, develops and implements measures for the maintenance of a safe work environment and ensures that individuals can openly express safety concerns.
  • Sentinel event: a wholly unexpected or unacceptable adverse event that results in serious injury or death of a patient
  • Violation: deliberate deviation from standards, laws, or rules, which could potentially result in harm to the patient

Errors are unintentional or accidental whereas violations are conscious and deliberate.

Medical error

  • One of the greatest threats to quality and patient safety is medical error.
  • It is the 3rd leading cause of death in the United States, responsible for approx. 200,000 deaths per year.

Risk factors and hazards

  • Inexperienced healthcare personnel
  • Poor communication due to, e.g.:
    • Illegible handwriting (e.g., on order sheets or prescription pads)
    • Lack of standardized terminology and use of jargon
    • Lack of personnel skilled in foreign languages (e.g., Spanish)
  • Improper documentation (e.g., patient allergies)
  • Overworked healthcare personnel
  • Similar drug names or packaging
  • Improper introduction of new procedures, guidelines, standards, etc.
  • Complex, new, outdated, or malfunctioning equipment

Types of error

Definition Examples
Active error
  • Error at the direct level of contact between healthcare personnel and patients
  • Has an immediate impact on the patient
  • Surgery on the incorrect site
  • Wrong route of drug administration
Latent error
  • Flaws in hospital organization
  • Implementation of new equipment without adequate staff training
Communication error
  • Error in communication between the healthcare personnel and the patient as well as among healthcare personnel
  • Errors in:
    • History taking
    • Explaining planned medical procedures to the patient
    • Written communication (e.g., poor handwriting)
    • Verbal communication (e.g., using nonstandard terminology or jargon)
Diagnostic error
  • Errors or delays in diagnosis
  • Not ordering the required investigations
  • Use of outdated tests
  • Failure to adequately monitor clinical signs or laboratory studies
Treatment error
  • Errors or delays in treatment
  • Inappropriate medical procedures
  • Incorrect administration of treatment
  • Incorrect drug dosage or method of use
  • Failure to provide treatment or respond to diagnoses in a timely manner
Preventive error
  • Errors in prophylaxis
  • Failure to implement appropriate prophylaxis
  • Failure to provide adequate monitoring or follow-up treatment
  • Failure in equipment and system maintenance

Responding to medical errors

  • Implement corrective measures immediately to minimize patient harm.
  • Disclose error to the patient and, if necessary, a senior medical professional.
    • There are several elements of an optimal error disclosure
      • Clearly admit an error has occured
      • State the course of events leading to and during the error, avoiding jargon
      • Explain the consequences of the error, both immediate and long term (if necessary)
      • Describe corrective steps and future preventative steps
      • Express personal regret and apology
      • Allow ample time for questions and continued dialogue
  • If a physician believes that a colleague has committed an error in a patient's care, the physician should urge their colleague to report this error to the patient.
  • If the colleague refuses, the physician should report this error via their hospital's or clinic's standard protocol.
  • If the cause of an error is not immediately known, the physician should inform the patient and maintain contact while investigations are being carried out.
  • Foster a just culture that focuses on systems errors and discourages ascribing blame to individuals, yet also holds individuals accountable for their actions, while discouraging blame.

Regardless of the outcome of a treatment, a physician must inform the patient immediately if an error has occurred and disclose the nature of that error!


Error prevention

Swiss cheese model of error causation

  • The Swiss cheese model illustrates how any safety system (slice of cheese) will have flaws (holes), either due to active failure or latent conditions, that allow errors or hazards to pass through safeguards and cause harm.
  • A multilayered safety system; (multiple slices of cheese) reduces the risk of error and harm by ensuring that if a hazard manages to pass through a hole in one layer, a subsequent layer will likely block its further passage through the system.
  • When the flaws in the individual layers align, a hazard or error can result in harm.

Human factors and ergonomics

  • Definition: The design and engineering of equipment, systems, processes, methods, and environments to fit the individuals who interact with them with the goal of reducing error while improving efficiency, productivity, safety, and comfort.
  • Incompatibilities between health care personnel and the equipment they use, constitute a patient safety risk/hazard.
  • Safety risks can be minimized by:
    • Forcing functions
      • Equipment, process, method, or system design features that prevent error by forcing the best option by default.
      • Most effective technique for minimizing adverse events, as it inhibits a chain of action that cause or perpetuate error.
      • Examples:
        • Anesthesia gas cylinders with gas-specific nozzles for different gases
        • Software that prevents incorrect dosages of drugs and warns the user of potential adverse reactions or interactions.
        • Avoiding shared storage of drugs with similar labels or names
    • Standardization
      • The development and implementation of standards that apply to various aspects of a process or system in order to improve reliability, efficiency, communication, and safety.
      • Examples:
        • Standardized protocols and guidelines: help ensure a consistent level of quality and increase efficiency
        • Standardized equipment: facilitates use across a system
        • Standardized checklists: help prevent common errors
        • Standardized terminology: helps prevent communication errors
    • Simplification
      • The reduction of complexity of equipment, systems, and processes to increase efficiency and reduce the risk of error.
      • Examples:
        • Ordering laboratory tests electronically
        • Streamlining administration
        • Readily available standard equipment (e.g., tongue depressors, latex gloves, scissors)

Medical error analysis

Root cause analysis

  • Definition: a retrospective analysis performed after a medical error has occurred in order to identify the (root) causes of the error and implement measures to prevent recurrence
  • Procedure:
    1. Identify the medical error (“what happened?”)
      • Involves a retrospective analysis of all possible factors that could have led to the error
    2. Identify what could have prevented the error from occurring (“why did it happen?”)
      • Tool used: Fishbone diagram (Ishikawa diagram, cause and effect diagram)
    3. Implement preventive measures (“what can be done to prevent recurrence?”)
      • Examples: updating technology, employing double checks, using checklists, staff education on new policies

Failure mode and effects analysis (FMEA)

  • Definition: : A prospective analysis to anticipate potential risks and hazards and proactively implement measures to prevent a medical error from occurring
  • Procedure:
    1. Identify what could go wrong and what impact that could have (failure mode)
    2. Identify why it could go wrong (failure causes)
    3. Identify the outcomes of the potential failures (failure effects)
    4. Proactive implementation of corrective measures

Health care quality

Domains of health care quality (STEEEP)

  1. Safe: Avoid or minimize risks and hazards that may lead to harm.
  2. Timely: Reduce delays in administering healthcare that may lead to harm.
  3. Effective: Provide evidenced-based healthcare; avoid services or treatments of doubtful benefit.
  4. Efficient: Minimize or avoid wasting medical equipment, time, and energy.
  5. Equitable: Provide equal care to all irrespective of gender, ethnicity, sexuality, and socioeconomic status.
  6. Patient-centered: Individualize treatment with respect for patient preferences, values, and needs.

Measurement of health care quality

Measures of health care quality allow us to compare the performance of individuals and hospitals at a particular point in time as well as an improvement or deterioration in the quality of health care over a period of time.

Definition Examples
Structural measures
  • Measures of the resources available to a healthcare facility
  • Physician-patient ratio
  • Number of beds
  • Number of nutritionists available for diabetic patients
Process measures
  • Percentage of individuals who receive a particular preventive service (e.g., immunizations, cancer screening, HbA1C measurement) over a period of time
Outcome measures
  • Measures of the final impact of service provided by a healthcare facility, including of mortality and morbidity
Balancing measures
  • Measures of the impact of one system on another
  • Cost-benefit analysis (e.g., using number needed to treat) of hiring more nutritionists to educate diabetic patients
  • Pareto chart: a bar graph with bars representing the frequency or cost of problems
    • Used to identify the significance of individual problems and help analyze how certain factors contribute to a variety of issues
  • Shewhart chart (control chart): a graphic representation in which data is plotted over time to determine if a perceived improvement in quality over time is statistically significant.
  • Run chart (time plot): a line graph that plots data in a time sequence to analyze trends.
    • Run charts are used in healthcare quality improvement, for example, to analyze the impact of an intervention over time and to help determine whether the improvement is a random or a true trend.
  • Convenience sampling: a study population that is drawn from a population that is easy to reach. Since the study population is not chosen at random, this type of study can lead to bias and may not be as effective as a randomized control trial.

Improvement of health care quality

Quality improvement is a continuous process of prospectively and retrospectively reviewing measures of quality control and maintenance to progressively improve the standard of healthcare and prevent medical error.

Models to improve healthcare quality

  • SMART criteria to improve patient safety: goals should be Specific, Measurable, Achievable, Realistic, and Timely.

  • Plan, do, study, act cycle (PDSA)

    • Plan: Define an area that needs improvement and plan potential interventions or innovations to bring about a corrective change.
    • Do: Test the new intervention.
    • Study: Assess the impact of the intervention on quality of healthcare.
    • Act: Implement the new intervention if the previous test showed a positive impact on healthcare quality or restart the cycle if the results were negative or negative.
  • Lean process improvement: the process of continually evaluating the methods used to identify and eliminate factors that use time, energy, and resources without improving patient outcome (e.g., avoiding unnecessary investigations)


  • 1. Quantros. Medical error—the third leading cause of death in the US. url: http://healthofamericans.org/files/Medical_error.pdf Accessed February 1, 2019.
  • 2. Kaplan Medical. USMLE Step 2 CK Lecture Notes 2017: Psychiatry, Epidemiology, Ethics, Patient Safety. New York, NY: Simon and Schuster; 2016.
  • 3. Le T, Bhushan V,‎ Sochat M, Chavda Y, Zureick A. First Aid for the USMLE Step 1 2018. New York, NY: McGraw-Hill Medical; 2017.
  • 4. Agency for Healthcare Research and Quality. Types of Health Care Quality Measures. https://www.ahrq.gov/talkingquality/measures/types.html. Updated February 1, 2015. Accessed February 1, 2019.
  • 5. ASQ. What is a Pareto Chart?. https://asq.org/quality-resources/pareto. Accessed February 1, 2019.
  • Drake R, Vogl AW, Mitchell AWM. Gray's Anatomy for Students International Edition. Elsevier Health Sciences; 2009.
last updated 04/23/2019
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