It's 3 a.m. in the middle of a busy Friday shift. The paramedics bring in a 54-year-old man who ingested a large amount of verapamil SR and Vicodin 90 minutes earlier. The patient is conscious but drowsy, with a blood pressure of 90/60 mm Hg.
You know that the recommended approach to patients with calcium channel blocker overdose and opiate toxicity changed recently. Besides calling the local poison control center — always indicated when dealing a potentially unstable toxicology patient — where can you turn for up-to-date information?
Smart phone or tablet apps might seem a natural choice to provide useful clinical guidelines. They can be updated frequently as new data become available, user input can be incorporated to eliminate errors and outdated information, and their content feasibly can be much more current than that in textbooks.
All these are theoretical advantages of apps. Unfortunately, in reality, some publishers just reproduce textbook contents and charge full hard-copy price for the app. The apps offer portability, but this practice has significant limitations. Information is difficult to access when viewed on a tiny phone screen. Scrolling through little bits of text is much less efficient than scanning a book chapter. (Admittedly, this is less of a problem on the larger screen of a tablet such as the iPad.) And the search and index functions of many apps leave much to be desired.
Still, apps are an increasingly popular source of clinical information, and deserve critical scrutiny. I used three topics as benchmarks in evaluating some of the toxicology information available in the iTunes store — sorry, Android users.
Whole bowel irrigation: Many toxicologists are moving away from this mode of gastrointestinal decontamination. I don't believe it was ever proven beneficial, and it definitely has significant risks. I'd be somewhat reluctant to trust an app in other areas if it were cavalier about recommending whole bowel irrigation, especially for sustained-release preparations.
Management of calcium channel blocker overdose: The use of high-dose insulin/euglycemia therapy has been accepted as an effective early intervention over the past decade or so. An app that did not reflect this approach would appear to be at least five years behind the times.
Naloxone: Many dark years ago, during the Neolithic period of medicine, the standard starting dose of naloxone for patients with known or suspected opiate overdose was 2 mg IV or IM. It became apparent that this practice would almost certainly precipitate acute opiate withdrawal, and gradually the recommended initial dose dropped to 0.4 mg. Many toxicologists today suggest starting with as little as 0.04 mg.
What would the apps recommend for these three topics? I looked at the app versions of three popular textbooks.
Emergency Medicine Manual ($69.95): The section on gastrointestinal decontamination states that whole bowel irrigation “may be useful in eliminating sustained release preparations.” It also states in passing that use of insulin is “anecdotal” for managing calcium channel blocker overdose, and gives an initial bolus dose that is 10 times lower than currently recommended. The book's discussion of naloxone is baffling, basing the initial dose on whether the patient is dependent on opioids, a bit of history that might not be apparent on initial presentation.
The bottom line is that this app seems to be a version of the Emergency Medicine Manual (Ma and Cline, editors) released in 2003, an edition no longer in print. In fact, most of the toxicology information here seems to be at least a decade old. Although the iTunes listing says the last update was May 23, 2011, this may have been simply a software tweak that did nothing to make the material more current. A more recent edition of the manual was released as a book in June 2012 under the title Tintinalli's Emergency Medicine Manual. I would not recommend this app until that version is available.
5-Minute Emergency Medicine Consult ($99.99): This app recommends considering use of whole bowel irrigation “in toxins not well adsorbed by charcoal (e.g., iron and lithium), body packers/stuffers, [and] sustained-release ingestions.” The section on calcium channel blocker overdose mentions at least seven potential interventions including glucagon and amrinone before it gets to insulin, stating simply that insulin “promotes more efficient myocardial carbohydrate metabolism.” It also suggests that whole bowel irrigation in this overdose is “beneficial with ingestion of sustained-release preparations.” The app also says to “start with low doses [of naloxone] for opiate-habituated patients.” One has to scroll further down the page to see that the recommended starting dose is 0.4–2.0 mg.
This app has a fair amount of good general emergency medicine information, but the bottom line is at least some of the toxicology section is already out of date, and the bullet point structure of its chapters results in a confusing failure to prioritize recommended interventions. This could well prove problematic especially when dealing with a sick unstable patient. I would recommend this app with reservations.
Poisoning & Drug Overdose ($69.99): The section on decontamination lists among indications for whole bowel irrigation “large ingestions of sustained-release or enteric-coated tablets containing valproic acid, theophylline, aspirin, verapamil, diltiazem, or other dangerous drugs.” The app's chapter on managing calcium channel blocker overdose has a streamlined, succinct list of interventions, with high-dose insulin/euglycemia listed as the second one, just behind calcium bolus. The third intervention is intralipid infusion, a relatively new concept that is not mentioned in the other books. The app's naloxone recommendation states that “0.2–0.4 mg IV or IM is usually effective.”
The bottom line is that this app basically reproduces material in the latest (sixth) edition of Kent Olson's text Poisoning & Drug Overdose, which was released in September 2011. It naturally has more information about a wider range of subjects than do toxicology sections in general emergency medicine texts because it is devoted entirely to toxicology. The format used makes the text quite accessible, especially when viewed on the iPad. The section on calcium channel blocker overdose is quite current, but the discussions of whole bowel irrigation and naloxone suggest that the material here must be interpreted critically and not followed blindly. I would recommend Poisoning & Drug Overdose as a toxicology reference that covers an extremely broad range of topics.
Disclosure:5-Minute Emergency Medicine Consult is published by Lippincott Williams & Wilkins, the same company that publishes EMN, and I wrote some of the toxicology chapters for earlier editions of the book.
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© 2012 Lippincott Williams & Wilkins, Inc.
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