Cardiovascular drugs: Linked to many errors

Drug products used to treat cardiovascular diseases (e.g., hypertension, congestive heart failure, ischemia, and arrhythmias) have been associated with a significant number of adverse drug events. Cardiovascular drug products are among the most widely used in both hospital and ambulatory care settings, and previous studies that have examined cardiovascular patients suggest that a significant degree of morbidity and mortality may be preventable.

Analyses of records submitted to USP's MEDMARX program from January 2001 through August 2004 revealed over 80,000 errors involving a cardiovascular drug product. Approximately 46% (n = 36,759) of these errors did reach the patient (categories C and higher) and 1.8% (n = 1,459) were harmful (categories E-I).

The most frequently reported types of errors involving cardiovascular drugs were Improper dose/quantity, Omission error, and Prescribing error. A two-way cross-tabulation analysis of types of errors by Error Category Index revealed that several types exceeded the historical overall percentage of harm of 1.87% for errors reported to MEDMARX from 1999 to 2003. Similar to previous MEDMARX reports, the findings indicate that the most harmful errors disproportionately arise from Wrong administration technique errors (6.4%).

In one case, an IV diltiazem drip was discontinued when the patient converted to a normal sinus rhythm, and an order for oral diltiazem 60 mg was made. However, 24 hours later, the patient returned to atrial fibrillation, necessitating an extra day in the hospital. It was discovered that the order for oral diltiazem 60 mg was never administered.

Observations 1. Pharmacies face a unique safety challenge in dispensing activities, given the large number of products used to treat the various cardiovascular diseases. Look-alike/sound-alike names, labeling and packaging similarities, and storage space limitations both in central and decentralized pharmacies as well as within automated dispensing devices can all contribute to the risk of an error event.

2. Although improper dose/quantity errors and prescribing errors were the first and third most frequently reported types of errors, neither fell into the top five most harmful error types (i.e., neither resulted in a percentage of harm that exceeded the overall 1.8% of harm for all cardiovascular agents). Omission errors, sometimes thought to be relatively "benign" types of errors, resulted in a harmful outcome nearly twice as often as other types of errors overall. This finding provides further evidence that omission errors can and do negatively impact patient care.

3. Causes of error that involve some aspect of communication (e.g., verbal orders, illegible handwriting, abbreviations, look-alike or sound-alike names) comprise 37% of all causes, thereby approaching the top error cause-performance deficit. Combined causal factors associated with transcription and documentation followed in frequency with 30%; computer entry-related activities 15%; and knowledge deficit 11%. These broad areas appear to comprise a large majority of the causes associated with cardiovascular drug errors and are worthy of further focus by healthcare facilities.

Safety recommendations General approaches to improving medication safety also apply to improving the safety of medications used in treating cardiovascular diseases: