Errors related to missed or delayed diagnosis are frequently a cause of patient injury and therefore an underlying cause of patient safety related events. Autopsy analysis spanning several decades show error rates at four to 50 percent, according to an article released by the Pennsylvania Patient Safety Authority and published in its September Pennsylvania Patient Safety Advisory.

Diagnostic error is a diagnosis that is missed, incorrect, or delayed as detected by a subsequent definitive test or finding. Not all misdiagnosis results in harm and harm may be due to either disease or intervention.

Diagnostic errors are encountered in every specialty and are generally lowest (less than five percent) for certain specialties that rely on visual pattern recognition and interpretation (e.g., radiology, pathology, dermatology). Error rates in specialties that rely more on data gathering and the combination of different elements for a conclusive diagnosis are higher (10 to 15 percent).

"Diagnostic errors are often the first or second leading cause of medical malpractice claims in the United States," Dr. John Clarke, clinical director of the Pennsylvania Patient Safety Authority said. "They account for twice as many ongoing and settled claims as medication errors."

Clarke added that studies have also shown that both cognitive errors and system design flaws contribute to diagnostic error.

"Communication issues, along with reasoning errors and system breakdowns all contribute to diagnostic errors," Clarke said. "The Advisory article reviews the common causes of diagnostic error and gives healthcare providers and patients information on how they can decrease the risk of a diagnostic error and thereby increase patient safety."

The Authority reviewed 100 events related to diagnostic error between June 2004 and November 2009 in an effort to determine if there were system solutions to diagnostic error, or if diagnostic error was so closely connected to doctors' cognitive processing that system solutions were not possible. Examples of reports were found in the Pennsylvania Patient Safety Reporting System (PA-PSRS) by searching on terms such as delayed diagnosis, wrong diagnosis, missed diagnosis, misdiagnosed, failure to diagnose, failure to treat and medical follow-up. Some of the sample reports with possible cognitive error examples include:

Report 1:

Patient seen in ED (emergency department) on day one and day two for complaints of shortness of breath and chest pain. Diagnosed with an upper respiratory infection and sent home each time. Subsequently later admitted and died. Coroner preliminary report indicated PE [pulmonary embolus] as cause of death.

Report 2:

A young man came to the ED for fainting and syncope, including the inability to speak for a few seconds with lateralizing symptoms and staring. In the ED, lab work was done but no CT [computed tomography] scan was ordered. Patient was discharged home with diagnosis of syncope and dehydration secondary to stress, with instructions to follow up with primary care physician. Subsequently, the primary care physician admitted the patient directly into the hospital, where a CT scan was performed and a brain lesion diagnosed.

Report 3:

Patient is an infant seen in the ED during high flu season after an episode of vomiting and period of apnea observed by family. Was discharged, but returned later. Family reported that the patient had another episode of apnea. Patient was evaluated and transferred to another facility for clinical impression of apnea and reflux.

One study cited in the article argued that even though doctors are well aware of the possibility of diagnostic error, doctors rarely believe that their own error rates are significant, further compounding the difficulty in analyzing diagnostic error.

More reports and examples of possible cognitive errors are provided in the Advisory article, "Diagnostic Error in Acute Care." Strategies to decrease diagnostic errors are also provided, along with a Patient Education Toolkit for healthcare providers.

The Authority's 2010 September Advisory contains other articles that contain toolkits for the healthcare provider to improve patient safety and more consumer tips for the patient to become involved in their healthcare. Highlights include:

-- Adverse Drug Events with HYDROmorphone: Pennsylvania Patient Safety Authority analysts reviewed medication errors and adverse drug reactions (ADR) involving HYDROmorphone that were reported to the Authority. Seventy percent of the wrong drug reports involved mix-ups with morphine. Wrong dose/overdosage medication error reports show that the most common reasons for error associated with this event type occur when administering, prescribing and dispensing. Sixty-five percent of the adverse reactions (e.g. central nervous system reactions) appear to have been preventable deaths. This article "Adverse Drug Events with HYDROmorphone: How Preventable Are They?" includes effective risk reduction strategies for healthcare providers and a sample tool that can be used to identify and monitor actual or potential problems with the use of HYDROmorphone.

-- Risks Associated with Dialysis: Pennsylvania healthcare facilities submitted 526 event reports involving hemodialysis administration to the Authority. Medication errors were the most common type of hemodialysis event submitted (29%). Other hemodialysis administration events involved failure to follow policy or protocol such as treatment set-up procedures (12.9%), needle disconnection and needle infiltration (6.1% for each category) and falls (5.9%). Risk mitigation strategies to prevent the likelihood of errors involving hemodialysis administration are provided in this article "Hemodialysis Administration: Strategies to Ensure Safe Patient Care." Hemodialysis consumer tips are also available on the Authority's website.

-- Pneumatic Tourniquets and the Risks: The Authority has received 140 event reports associated with pneumatic tourniquets. Pneumatic tourniquets are used primarily for reducing the blood flow during limb surgery. Failure or misuse of the tourniquets can lead to complications for the patient. This article "Strategies for Avoiding Problems with the Use of Pneumatic Tourniquets" reviews the problems associated with pneumatic tourniquets and offers healthcare providers a poster with the recommended strategies for avoiding problems associated with using them.

-- Preventing Infections: Worth the Investment: Healthcare-associated infections (HAIs) account for about 1.7 million infections and 99,000 deaths in the U.S. each year. This number represents 4.5 infections for every 100 hospital admissions. Common misconceptions about HAIs are dispelled in this article, "Demonstrating Return on Investment for Infection Prevention and Control." The Centers for Disease Control and Prevention estimates that the $45 billion annual direct cost of HAIs could be significantly reduced by as much as $31.5 billion with well resourced, quality infection prevention and control programs. This article also gives facilities information on how they can investigate the true cost of HAIs or the cost-effectiveness of an infection prevention and control program.

-- Wrong-Site Surgery Update: Three years have passed since the Authority released its first definitive findings on wrong-site surgery in Pennsylvania in June 2007. After the initial focus on wrong-site surgery through the Authority, the number of events has decreased each year. However, Pennsylvania still averages more than one report a week. Of the 375 total reports of wrong-site surgery, 13 reports involved visible scars, melanomas, moles or other skin lesions. Wrong-site anesthetic blocks were also the cause of 14 events this past quarter (April 1, 2010 through June 30, 2010). Others included procedures involving the wrong device. The Authority's Preventing Wrong-Site Surgery web page has been organized for easier navigation of its many resources. They include sample forms, checklists, educational posters and videos, illustrative figures and tables, patient education brochures and online information from other sites. The Authority also has an on-site consultation program for Pennsylvania facilities that wish to analyze their vulnerabilities for wrong-site surgery. For more information on the wrong-site surgery prevention project go to the Advisory article "Quarterly Update on the Preventing Wrong-Site Surgery Project."

Source: Pennsylvania Patient Safety Authority