Chapter 3. Patient Safety

The Institute of Medicine (IOM) defines patient safety as "freedom from accidental injury due to medical care or medical errors."¹ In 1999, the IOM published To Err Is Human: Building a Safer Health System, which called for a national effort to reduce medical errors and improve patient safety.¹ Central to this effort is the ability to measure and track adverse events.

Measuring patient safety is complicated by difficulties in assessing and ensuring the systematic reporting of medical errors and adverse events. All too often, adverse event reporting systems are laborious and cumbersome. Health care providers may also fear that if they participate in the analysis of medical errors or patient care processes, the findings may be used against them in court or harm their professional reputations. Many factors limit the ability to aggregate data in sufficient numbers to rapidly identify prevalent risks and hazards in the delivery of patient care, their underlying causes, and practices that are most effective in mitigating them. These include difficulties aggregating and sharing data confidentially across facilities or State lines.

Despite these limitations, a better picture of patient safety is emerging. Progress has been made in recent years in raising awareness, developing reporting systems, and establishing national data collection standards. Examining patient safety using a combination of administrative data, medical record abstraction, spontaneous adverse event reports, and patient surveys allows a more robust understanding of what is improving and what is not. Still, data remain incomplete for a comprehensive national assessment of patient safety.²

Importance

Mortality

Cost

Measures

This year's patient safety chapter highlights four core measures and seven additional measures related to health care-associated infections (HAIs), surgical complications, other complications of hospital care, and complications of medications:

Core measures are:

• Appropriate timing of antibiotics among surgical patients.
• Postoperative care composite: pneumonia or venous thromboembolic event.
• Adverse events associated with central venous catheters (CVCs).
• Potentially inappropriate prescription medications for adults age 65 and over.

Additional noncore measures include:

• Catheter-associated urinary tract infections (UTIs).
• Postoperative sepsis.
• Postoperative respiratory failure.
• Accidental puncture or laceration.
• Deaths following complications of care.
• Adverse drug events in the hospital.
• Patient safety culture composite.

Findings

Health Care-Associated Infections

Infections acquired during hospital care (nosocomial infections) are one of the most serious patient safety concerns. They are the most common complication of hospital care.⁴ An estimated 1.7 million HAIs occur each year in hospitals, leading to about 100,000 deaths. The most common infections are urinary tract, surgical site, and bloodstream infections.⁵

A specific medical error cannot be identified in most cases of HAIs. However, better application of evidence-based preventive measures can reduce rates of HAIs within an institution. Such measures include using urinary catheters only when absolutely needed and administering prophylactic antibiotics before surgery at the right time.

Outcome: Catheter-Associated Urinary Tract Infections

The urinary tract is a common site of HAI. Urinary catheter use and specific comorbid conditions can increase the risk of developing a UTI. Approximately 40% of all HAIs are attributed to catheter-associated UTIs.⁶

Figure 3.1. Adult Medicare surgery patients with postoperative catheter-associated urinary tract infection, overall and by age, 2005-2007

Source: Centers for Medicare & Medicaid Services, Medicare Patient Safety Monitoring System (MPSMS), 2005-2007.
Denominator: Adult hospitalized Medicare fee-for-service discharges from the MPSMS sample having major surgery and meeting specific criteria for each measure.

• In 2007, the total percentage of adult Medicare surgical patients with catheter-associated UTIs was 4.9% (Figure 3.1).
• From 2005 to 2007, there were no statistically significant changes overall or for any age group.
• In all 3 data years, surgical patients age 85 and over were more likely to have catheter-associated UTIs compared with patients under age 65.
• In 2006 and 2007, patients ages 75-84 were also more likely to have these infections compared with patients under age 65.

Prevention: Appropriate Timing of Antibiotics Among Surgical Patients

Wound infection following surgery is a common HAI. Hospitals can reduce the risk of surgical site infection by making sure patients get the right antibiotics at the right time on the day of their surgery. Surgery patients who get antibiotics within the hour before their operation are less likely to get wound infections than those who do not. Getting an antibiotic earlier or after surgery begins is not as effective. However, taking these antibiotics for more than 24 hours after routine surgery is usually not necessary and can increase the risk of side effects, such as antibiotic resistance and serious types of diarrhea. Among adult Medicare patients having surgery, the National Healthcare Quality Report (NHQR) tracks receipt of antibiotics within 1 hour prior to surgical incision, discontinuation of antibiotics within 24 hours after end of surgery, and a composite of these two measures.

Figure 3.2. Adult surgery patients who received appropriate timing of antibiotics: Overall composite, by age, 2005-2007

Source: Centers for Medicare & Medicaid Services, Medicare Quality Improvement Organization Program, 2005-2007.
Denominator: Hospitalized patients having surgery.

• The percentage of adult surgery patients who received appropriate timing of antibiotics improved from 2005 (74.9%) to 2007 (86.4%) (Figure 3.2). Improvement was also seen among all age groups during this period.
• In all years, patients ages 65-74, 75-84, and 85 and over were less likely than patients under age 65 to receive appropriately timed antibiotics.

Figure 3.3. State variation: Adult surgery patients who received appropriate timing of antibiotics, 2007

Key: Best quartile indicates States with highest rates of adult surgery patients who received appropriate timing of antibiotics; worst quartile indicates States with lowest rates.
Source: Centers for Medicare & Medicaid Services, Medicare Quality Improvement Organization Program, 2007.
Denominator: Hospitalized patients having surgery.

• The 13 Statesⁱ in the best quartile (highest rates of adult patients who received appropriate timing of antibiotics) in 2007 (Figure 3.3) had a combined average rate of 91.2%. These States are primarily located in New England and the Midwest.
• Eleven States,ⁱⁱ the District of Columbia, and Puerto Rico were in the worst quartile (lowest rates) in 2007 and had a combined average rate of 80.5%. These States are primarily located in the West and Southwest.

Outcome: Postoperative Sepsis

Sepsis, a severe bloodstream infection, can occur after surgery. Rates can be reduced by giving patients appropriate prophylactic antibiotics 1 hour prior to surgical incision.

Figure 3.4. Postoperative sepsis after an operating room procedure per 1,000 elective surgery discharges, adults age 18 and over, 2004-2006

Source: Agency for Healthcare Research and Quality, Healthcare Cost and Utilization Project, Nationwide Inpatient Sample, 2004-2006.
Note: Rates are adjusted by age, gender, age-gender interactions, comorbidities, and diagnosis-related group clusters.

• From 2004 to 2006, the rate of postoperative sepsis increased from 13.2 to 15.1 per 1,000 elective surgery discharges of adults age 18 and over (Figure 3.4). Rates increased for patients with private insurance, Medicare, and Medicaid.
• In all years, patients with Medicare and Medicaid had higher rates of postoperative sepsis than patients with private insurance.

Surgical Care

Adverse health events can occur during episodes of care, especially during and soon after surgery. Although some events may be related to a patient's underlying condition, many can be avoided if appropriate care is provided.

Outcome: Postoperative Care Composite

Complications after surgery may include, but are not limited to, pneumonia and blood clots.

Figure 3.5. Composite measure: Adult Medicare surgery patients with postoperative complications (postoperative pneumonia or venous thromboembolic event), 2002-2007

Source: Centers for Medicare & Medicaid Services, Medicare Patient Safety Monitoring System (MPSMS), 2002-2007.
Denominator: Adult hospitalized Medicare fee-for-service discharges from the MPSMS sample having major surgery and meeting specific criteria for each measure.

• From 2002 to 2007, the overall percentage of adult surgery patients who had postoperative pneumonia or a thromboembolic event decreased from 3.4% to 1.4%. During the same period, the percentage of adult surgery patients ages 65-74 and 75-84 with postoperative complications also decreased significantly (Figure 3.5).
• In all data years, adult surgery patients ages 75-84 were more likely to have postoperative complications compared with those ages 65-74.

Outcome: Postoperative Respiratory Failure

Respiratory failure is not uncommon after surgery and may necessitate reintubation or prolonged mechanical ventilation. Causes include oversedation, exacerbation of underlying cardiovascular or respiratory conditions, and ventilator-associated pneumonia. Although some cases of respiratory failure cannot be prevented, closer attention to risk factors can reduce rates within an institution.

Figure 3.6. Postoperative respiratory failure per 1,000 elective surgery discharges after an operating room procedure, adults age 18 and over, 2004-2006

Source: Agency for Healthcare Research and Quality, Healthcare Cost and Utilization Project, Nationwide Inpatient Sample, 2004-2006.
Note: Rates are adjusted by age, gender, age-gender interactions, comorbidities, and diagnosis-related group clusters.

• From 2004 to 2006, there were no statistically significant changes in rates of postoperative respiratory failure per 1,000 elective surgery discharges of adults age 18 and over for most insurance groups (Figure 3.6). However, for uninsured/self-pay patients, rates increased from 10.3 to 11.6.
• In all years, patients with Medicare and Medicaid had higher rates of postoperative respiratory failure than did patients with private insurance. In 2005 and 2006, rates were also higher among uninsured/self-pay patients than among patients with private insurance.

Figure 3.7. Postoperative respiratory failure per 1,000 elective surgery discharges after an operating room procedure, children under age 18, 2004-2006

Source: Agency for Healthcare Research and Quality, Healthcare Cost and Utilization Project, Nationwide Inpatient Sample, 2004-2006.
Note: Rates are adjusted by age, gender, age-gender interactions, comorbidities, and diagnosis-related group clusters.

• From 2004 to 2006, there were no statistically significant changes in rates of postoperative respiratory failure per 1,000 elective surgery discharges of children under age 18 overall or for any insurance group (Figure 3.7).
• In all years, pediatric patients with Medicare and Medicaid had higher rates of postoperative respiratory failure than patients with private insurance. Rates were also significantly higher among uninsured/self-pay patients in 2004 and 2006 than among those with private insurance.

Other Complications of Hospital Care

Besides surgery, other types of care delivered in hospitals can place patients at risk for injury or death.

Outcome: Adverse Events Associated With Central Venous Catheters

Patients who require a CVC to be inserted into or from the great vessels leading to the heart tend to be severely ill. However, the placement and use of these catheters can result in infections and other complications.

Figure 3.8. Bloodstream infections or mechanical adverse events associated with central venous catheter placement: Overall composite, by age, 2005-2007

Source: Centers for Medicare & Medicaid Services, Medicare Patient Safety Monitoring System (MPSMS), 2005-2007.
Denominator: Adult hospitalized Medicare fee-for-service discharges from the MPSMS sample with CVC placement.
Note: Mechanical adverse events include allergic reaction (to the catheter), tamponade, perforation, pneumothorax, hematoma, shearing off of the catheter, air embolism, misplaced catheter, thrombosis or embolism, knotting of the pulmonary artery catheter, and certain other events.

• From 2005 to 2007, there were no statistically significant changes overall or for any age group in the percentage of CVC placements with associated complications (Figure 3.8).

Outcome: Accidental Puncture or Laceration

Adverse events, including the nicking or cutting of bodily organs and blood vessels, are possible during any operation or procedure. This may be especially true in emergent situations, when, according to an expert panel review, some of these occurrences are not preventable. Puncture or laceration can lead to serious complications.⁷

Figure 3.9. Accidental puncture or laceration during procedure per 1,000 discharges, adults age 18 and over, 2004-2006

Source: Agency for Healthcare Research and Quality, Healthcare Cost and Utilization Project, Nationwide Inpatient Sample, 2004-2006.
Note: Rates are adjusted by age, gender, age-gender interactions, comorbidities, and diagnosis-related group clusters.

• From 2004 to 2006, there were no statistically significant changes in the rate of accidental puncture or laceration during procedure for adults age 18 and over overall or for any insurance group (Figure 3.9).
• In all data years, those who were uninsured/self-pay/no charge were less likely to have accidental puncture or laceration during a procedure compared with all other insurance groups.

Outcome: Deaths Following Complications of Care

Many complications that arise during hospital stays cannot be prevented. However, rapid identification and aggressive treatment of complications may prevent these complications from leading to death. Deaths following complications of care, also called "failure to rescue," is an indicator that tracks deaths among patients whose hospitalizations are complicated by pneumonia, thromboembolic events, sepsis, acute renal failure, gastrointestinal bleeding or acute ulcer, shock, or cardiac arrest.⁷

Figure 3.10. Deaths per 1,000 discharges with complications potentially resulting from care (failure to rescue), adults ages 18-74, by insurance, 2004-2006

Source: Agency for Healthcare Research and Quality, Healthcare Cost and Utilization Project, Nationwide Inpatient Sample, 2004-2006.
Denominator: Patients ages 18-74 years from U.S. community hospitals whose hospitalizations are complicated by pneumonia, thromboembolic events, sepsis, acute renal failure, gastrointestinal bleeding or acute ulcer, shock, or cardiac arrest.
Note: Rates are adjusted by age, gender, comorbidities, and diagnosis-related group clusters.

• From 2004 to 2006, the rate of deaths following complications of care declined from 128.9 to 114.0 per 1,000 admissions of adults ages 18-74 (Figure 3.10). A significant decrease was also seen among all insurance groups during the same period.
• In all data years, uninsured individuals were more likely to have deaths potentially resulting from care compared with all other insurance groups.

Complications of Medications

Complications of medications are common safety problems. Some, but not all, adverse drug events may be related to misuse of medication. However, prescribing medications that are inappropriate for a specific population may increase the risk of adverse drug events.

Outcome: Adverse Drug Events in the Hospital

Some medications used in hospitals can cause serious complications. The Medicare Patient Safety Monitoring System tracks a number of adverse drug events, including serious bleeding associated with intravenous heparin, low-molecular-weight heparin, or warfarin, and hypoglycemia associated with insulin or oral hypoglycemics.

Figure 3.11. Hospitalized Medicare patients with adverse drug events, 2004-2007

Source: Centers for Medicare & Medicaid Services, Medicare Patient Safety Monitoring System (MPSMS), 2004-2007.
Denominator: Adult hospitalized Medicare fee-for-service discharges from the MPSMS sample receiving specified medication.

• In 2007, adverse drug events in the hospital related to some frequently used medications ranged from 3.4% of Medicare patients who received low-molecular-weight heparin to 8.9% of Medicare patients who received intravenous heparin (Figure 3.11).
• The rates of each adverse drug event decreased significantly from 2004 to 2007.

Outcome: Potentially Inappropriate Prescription Medications for Adults Age 65 and Over

Some drugs are considered potentially harmful for older patients but nevertheless were prescribed to them.^8,iii

Figure 3.12. Adults age 65 and over who received potentially inappropriate prescription medications in the calendar year, 2002-2006

Source: Agency for Healthcare Research and Quality, Medical Expenditure Panel Survey, 2002-2006.
Denominator:Civilian noninstitutionalized population age 65 and over.
Note: Prescription medications received include all prescribed medications initially purchased or otherwise obtained, as well as any refills.

• From 2002 to 2006, the percentage of older patients who reported purchasing at least 1 of 33 potentially inappropriate drugs decreased significantly, from 18.4% to 15.7% (Figure 3.12).
• From 2002 to 2006, the rate of patients who received potentially inappropriate medication decreased significantly among those with Medicare and private insurance or Medicare and other public insurance.

Focus on Patient Safety Culture

High-reliability organizations that achieve low rates of adverse events establish "cultures of safety." A culture of safety is characterized by shared dedication to making work safe, blame-free reporting and communication about error, collaboration and teamwork across disciplines, and adequate resources to prevent adverse events. AHRQ developed the Hospital Survey on Patient Safety Culture to help hospitals assess the culture of safety in their facilities. AHRQ began producing comparative database reports in 2007 to help hospitals assess their performance relative to similar institutions.

In this NHQR, we present data from the Hospital Survey on Patient Safety Culture: 2009 Comparative Database Report.⁹ This report is based on survey responses collected in 2008 from nearly 200,000 hospital staff in 622 hospitals. The average hospital response rate was 52%, with an average of 316 completed surveys per hospital. Most hospitals administered paper surveys rather than Web-based surveys. In addition, most hospitals administered the survey to all staff or a sample of all staff from all hospital departments. Nurses accounted for more than one-third of respondents, followed by "other." More than three-quarters of respondents had direct interaction with patients.

Results are presented for the 12 patient safety culture composites addressed in the survey, expressed as average percent positive response. Percent positive refers to the percentage of responses that agree or strongly agree with a positively worded item (e.g., "People support one another in this work area") and the percentage that disagree or disagree strongly with a negatively worded item (e.g., "We have safety problems in this work area"). Hospitals contributing data to the comparative database mirror the population of U.S. hospitals as a whole, but participation is entirely voluntary. Thus, findings may not be generalizable to all types of facilities.

Figure 3.13. Patient safety culture composites, all hospitals, 2008

Source: Agency for Healthcare Research and Quality, Hospital Survey on Patient Safety Culture: 2009 Comparative Database Report.

• A strength for most hospitals was Teamwork Within Units, the extent to which staff support each other, treat each other with respect, and work together as a team.
• Many hospitals performed poorly on Nonpunitive Response to Error, the extent to which staff feel that their mistakes and event reports are not held against them and that mistakes are not kept in their personnel file. Similar results were seen for Handoffs and Transitions, the extent to which important patient care information is transferred across hospital units and during shift changes.

References

1. Kohn L, Corrigan J, Donaldson M, eds.  To err is human: building a safer health system. Washington, DC: Institute of Medicine, Committee on Quality of Health Care in America; 2000.

2. Aspden P, Corrigan J, Wolcott J, et al.  Patient safety: achieving a new standard of care.  Washington, DC: Institute of Medicine, Committee on Data Standards for Patient Safety; 2004.

3. Encinosa WE, Hellinger FJ. The impact of medical errors on ninety-day costs and outcomes: an examination of surgical patients. Health Serv Res 2008 Dec;43(6):2067-85. Epub 2008 Jul 25.

4. Thomas EJ, Studdert DM, HR B, et al. Incidence and types of adverse events and negligent care in Utah and Colorado. Med Care 2000;38:261-71

5. Klevens RM, Edwards JR, Richards CL, et al. Estimating health care-associated infections and deaths in U.S. hospitals, 2002. Pub Hlth Rep 2007;122:160-6.

6. Tambyah PA, Maki DG.  Catheter-associated urinary tract infection is rarely symptomatic: a prospective study of 1,497 catheterized patients.  Arch Intern Med 2000 Mar 13;160(5):678-82.

7. Guide to Patient Safety Indicators Version 3.1. Rockville, MD: Agency for Healthcare Research and Quality; 2003. Available at: http://www.qualityindicators.ahrq.gov/downloads/psi/word/psi_guide_v31.doc. Accessed on November 17, 2009.

8. Zhan C, Sangl J, Bierman AS, et al. Potentially inappropriate medication use in the community-dwelling elderly: findings from the 1996 Medical Expenditure Panel Survey. JAMA 2001 Dec 12;286(22):2823-9.

9. Hospital Survey on Patient Safety Culture: 2009 comparative database report. Rockville, MD: Agency for Healthcare Research and Quality; 2009. AHRQ Publication No. 09-0030. Available at: https://www.ahrq.gov/qual/hospsurvey09/. Accessed on June 15, 2009

ⁱ The States are Delaware, Maine, Massachusetts, Michigan, Montana, Nebraska, New Hampshire, New Jersey, North Carolina, South Carolina, South Dakota, Vermont, and Wisconsin.
ⁱⁱ The States are Arizona, California, Georgia, Idaho, Louisiana, Mississippi, Nevada, New Mexico, Oregon, Texas, and Utah.
ⁱⁱⁱ Drugs that should always be avoided for older patients include barbiturates, flurazepam, meprobamate, chlorpropamide, meperidine, pentazocine, trimethobenzamide, belladonna alkaloids, dicyclomine, hyoscyamine, and propantheline. Drugs that should often or always be avoided for older patients include carisoprodol, chlorzoxazone, cyclobenzaprine, metaxalone, methocarbamol, amitriptyline, chlordiazepoxide, diazepam, doxepin, indomethacin, dipyridamole, ticlopidine, methyldopa, reserpine, disopyramide, oxybutynin, chlorpheniramine, cyproheptadine, diphenhydramine, hydroxyzine, promethazine, and propoxyphene.

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