Topics in Advanced Practice Nursing eJournal 2(4), 2002. © 2002 Medscape

Abstract

Since their introduction in the last decade of the twentieth century, personal digital assistants (PDAs) have become useful tools for personal information management. For healthcare professionals, these devices can increase productivity by providing ready access to large amounts of clinical and reference material. Yet, the wide assortment of available PDA styles, brands, and models can make the job of selecting a device that will best suit a particular clinician's needs quite challenging.

This article will explain the basics of PDA operation, including common PDA terms and features. Products will be discussed systematically by style, operating system (OS), brand, and model, the process of choosing a particular device will be analyzed and demystified. Buying considerations such as memory size and differences in processor speed across styles will be explained, and examples of clinical software relevant to advanced practice nursing (APN) practice will be presented. This will enable the reader to make a more informed choice when buying a PDA.

Introduction

In the past several years, the concept of a versatile, multifunctional, handheld computing device has become reality with the advent of PDAs. These devices are extremely popular with consumers. Not only do PDAs provide users with a portable information management platform, they also provide software applications tailored to specific professions ("vertical markets"). For APNs and other health professionals, using a PDA with medical software is touted as a sophisticated way to manage personal information while having a litany of clinical data immediately available. However, with so many different PDAs available, and even more software to choose from, how do you decide which products and software will work best for you?

Like many, my expertise with computing devices has not been gained through any formal program of study, but learned through experience. After purchasing a PDA 2 years ago, I now consider it one of my most useful clinical tools. Based on numerous discussions with friends and colleagues, it has become apparent that a brief primer on PDAs and software could be helpful. This article will discuss the different types of PDAs available, as well as types of software applications that an APN might find useful. Additionally, PDA and applicable software Web site addresses are provided. For clarity, the term "PDA" will be used to refer to all handheld computing devices, as opposed to terms like "Palm Pilot" or "Pocket PC", which actually refer to specific types of PDAs.

All PDAs have some common features. They are handheld devices, roughly the size of a deck of cards, powered by either rechargeable or alkaline batteries. They have liquid crystal displays that may be either monochrome or color, with varying degrees of clarity and sharpness. All PDAs come with a stylus, a small pen-shaped tool used to tap on the screen to select characters and functions. All PDAs incorporate various types of handwriting recognition; this allows the user to tap, draw, or write on the screen, using the stylus to input and/or select data. In addition, PDAs come with preinstalled programs such as a date book, calculator, address book, and a memo pad.

Most PDAs come with a cradle or a special cable used to connect with a desktop computer. Regular synchronization of the PDA with the desktop computer ensures optimal PDA performance. Synchronization is accomplished by placing the PDA in its cradle (or attaching it to the special cable) and pressing a button. Most PDAs also have an infrared (IR) port that can be used to send files to other PDAs in close proximity; this port can also be used to transmit data to other infrared devices, such as an IR-equipped printer.

Most PDAs have some sort of expansion slot, though the type of slot can vary, even within different models of the same brand. Expansion slots are used to plug in optional accessory modules that give the PDA additional capabilities. For example, memory modules provide additional memory for program storage; other types of modules allow for use of the PDA as a cell phone, Global Positioning System (GPS) receiver, or digital camera. If a PDA is equipped with a wireless modem, you can access the Internet from almost anywhere!

Differences in Architecture

It may be easier to understand the differences between PDAs by examining them systematically, looking from the general to the specific. The most general way to classify a computer is by its style, or architecture. When discussing home computers, most would recognize the 2 basic styles: the personal computer (PC), referring to a computer based on the original IBM PC and its successors (including PC-compatibles); and the "Mac", referring to the Macintosh made by Apple Computer.

Similarly, with PDAs, there are 2 basic styles: the "Palm," based on the original Palm Pilot by 3Com, and the Pocket PC. The major differences are based on the OS platform used in each.

Differences in Operating Systems

Like desktop computers, PDAs require an OS to run. There are 2 different PDA OSs in common use. Palm-based PDAs use Palm's OS (Palm OS), while Pocket PCs operate under Windows CE, a scaled-down, mobile version of Microsoft Windows. The OS used by a particular PDA is important to consider when purchasing a handheld device, because PDA software is designed for use with a specific OS. If a program you desire is not available in a version made for the OS your PDA uses, then you will not be able to use that program on your handheld device.

There are significant differences in the features of these 2 OSs. These differences need to be considered carefully, even before deciding on a brand or model. Palm OS is an OS designed specifically for PDAs. While Palm-based devices can (and do) interact with your desktop computer's environment, they only do so by way of an interface program running under the OS on your desktop PC. There is no desktop version of Palm OS.

The Palm OS is generally compatible with Apple's Macintosh OS (Mac OS); however, there are specific requirements that differ between PDA brands running the Palm OS, including which versions of Mac OS are compatible. Most PDAs also require that the Macintosh desktop have an available universal serial bus (USB) port for connecting with the PDA. It is important to note that some PDA models using the Palm OS are not compatible with Mac OS. Readers who desire to use a Palm OS device with a Macintosh desktop computer are strongly advised to check the model's specifications closely before making a purchase decision.

The Palm OS is thrifty on memory; one source indicates there are more than 7000 programs available that will run under it.^[1] That same source claimed that there were less than 200 compatible Pocket PC applications to choose from when the Pocket PC was first introduced. The author recommends Palm OS-based PDAs for this reason; more medical programs can be found in versions written for Palm-OS than for Windows CE, the OS that Pocket PCs use.

Windows CE is a scaled down, mobile version of Microsoft Windows. All Pocket PCs use this OS, known for its dazzling graphics and sound capabilities. Because of this, Pocket PCs require faster processors and more memory to operate efficiently. They run Microsoft Office programs such as Word and Excel in versions very similar to the ones on a desktop PC. Since these same programs exist on both the desktop PC and the Pocket PC, you can transfer files back and forth without having to first alter them with a third-party product so that they can be read (which you would have to do to use Microsoft Office files with a Palm OS-based device).

Since Pocket PCs are, by definition, mobile platforms for the Microsoft Windows OS, they are not designed to interface with Mac OS. The method used by Mac OS to organize file names with programs is completely different from the method used by Microsoft Windows.^[2] There are third-party products available that claim to overcome this incompatibility (see Table 1 for details).

Differences in Palm OS-Based Brands

Once you have decided on an OS, the next thing to consider is brand. If you've chosen a Palm OS-based product, the brands you could choose from include Palm, Handspring, and Sony. Palm is the original company that invented the PDA, and they designed Palm OS. Their gear is also fairly expandable, though some options are not interchangeable between all models. This may become an issue if you upgrade to another model of Palm later and wish to keep using your previously purchased optional devices. Handspring is a spin-off company headed by Jeff Hawkins. Hawkins invented the original Palm Pilot in the early 1990s while working at 3Com.^[1] Handspring has made some minor improvements to Palm OS. For example, Palm-brand products come with "Date Book," while Handspring-brand products also come with "Date Book Plus," which has some additional features.

One of the biggest advantages with the Handspring product line is that they offer quite a few expansion options. There are close to a dozen different modules you can buy to plug into the expansion slot of a Handspring. This expansion slot is also the same across all models of Handspring PDAs, so an optional device bought for one model will work in a different model, should you upgrade at a later date.

Differences in Pocket PCs and Other Brands

Pocket PC devices all use the same Windows CE OS, so the functionality across brands is very consistent. Hewlett-Packard, Compaq, and Casio are a few of the more well-known companies that make Pocket PCs. These devices are known for their superb graphics and sound. The Sony Clie also deserves mention. Somewhat of a hybrid, it uses the Palm OS and has all the functionality of a Palm-based device, but it also has superior graphics and sound, comparable with what is available on the Pocket PCs. For this reason, the Sony Clie is a bit more expensive than other Palm OS-based devices. According to Sony's Web site (Table), none of the Clie models are compatible with Mac-OS.

Features

After you pick a brand, you will then need to decide which model you want within that brand. This decision is based on what particular model has more of the features you like. Ask yourself if you need or want something like wireless Internet access, or a really thin carrying case. Other features you might find useful are battery type (rechargeable vs alkaline), color vs a grayscale display, or a specialty model, such as the newer combination PDA/cell phone. You might even decide you'd like one of the newer PDA models equipped with an alphanumeric touch keypad. The choice is yours -- pick the features that you think will suit your particular situation best.

Processor Speed

Important criteria to consider when choosing a PDA model are the type of processor chip and the memory size. Keep in mind that processor and memory requirements for a Pocket PC are totally different than those for a Palm OS-based device. The Pocket PC system requires a faster processor speed and more memory to support its superior graphics and sound. There is not as much variation in available processor speeds as there was perhaps a year ago; however, the requirements are still totally different between PDA styles. Palm OS-based products typically have a Motorola Dragonball processor running at 33 mHz; Pocket PCs typically have an Intel processor chip running at 133 mHz or higher. A general rule to apply, regardless of what style of PDA you are choosing, is "faster is better." Just remember that processor speed comparisons between the two styles of PDAs are invalid.

Memory

Palm OS-based PDAs typically come with 8 megabytes (MB) of memory, which is the minimum acceptable amount. Additional memory cards can be purchased and easily plugged in to the PDA by the user; some newer models have recently been introduced that come with 16 MB of internal memory. These are handy if you anticipate using a lot of programs and you expect to use a lot of add-on accessories as well, since these accessories plug into the same slot that would otherwise be needed for installing add-on memory. Beware of older Palm OS-based PDAs that have only 2 MB of memory; this is only enough to run the basic "day-planner" type applications that come preinstalled on the PDA. If you buy a 2-MB model, you most likely will not have sufficient memory to add any additional programs of your own.

A Pocket PC typically comes with 16 to 64 MB of memory. Note that a Pocket PC will typically use a third to half of its memory just to run the OS, leaving only the remainder actually available for storing programs. If you are running low on memory and wish to add more programs, you can adjust how much memory is available to your software applications by tweaking the system settings, but only to a point. This "additional" memory is obtained at the expense of system operating speed. For Pocket PCs, a minimum of 32 to 64 MB of memory is best. Models equipped with only 16 MB will not have enough room to add much additional software, especially considering that programs written for Windows CE tend to be larger than their Palm OS counterparts.^[1] Note that 16 MB represents a very desirable amount of memory for a Palm OS-based PDA, but is an insufficient amount for a Pocket PC.

There are many different medical software programs available for PDAs. Software is available to track patients, provide drug information, perform laboratory calculations, or obtain a quick refresher on many common diseases. While there are many, many programs available, here are just a few helpful examples. These represent only a tiny fraction of what is available; many additional Web sites about software and PDA technology can be found in the Table. Additionally, an Internet search engine, such as Hotbot or Google, may be helpful if you are trying to find a site that deals with a particular program or area of interest. Also, PDA buyer's guides and computing magazines are available at many newsstands and bookstores; they are an excellent source of information.

Patient Tracking

To keep track of patient information, Patient Keeper is a great tool. Designed by a medical student, it is an organizer that keeps track of a list of patients you enter, along with their history and physical, review of systems, labs, and other clinical data. Patient Keeper is available as shareware (meaning you can download a free demo to try, and then purchase later); it is available for Palm OS-based PDAs only.

Drug Information

For drug information, a favorite is ePocrates Rx. This program provides an up-to-date, comprehensive list of drugs and essential prescribing information. The drug information is updated every time users synchronize their PDAs, which means you will always have fairly current drug information. Another feature on ePocrates Rx is the ability to check for drug interactions with a list of up to 30 drugs that you select. It also lists prices for drug products, and the latest version can incorporate multiple insurance formularies, making it that much easier to prescribe a drug that will be covered under a patient's particular insurance plan.

A companion product, ePocrates ID, lets you view empirical and specific treatment for various types of infections. You can view by "bug," drug, or anatomic location. The program seamlessly integrates with ePocrates Rx, so when you click on a drug recommended for treating a particular infection, you are automatically taken to ePocrates Rx for the particulars on prescribing that drug. Both ePocrates Rx and ePocrates ID are freeware (downloadable at no cost to you) and are available for Palm OS-based PDAs. A similar product, Tarascon's ePharmacopoeia, is also available at no cost. This electronic version of the popular pocket reference also runs under Palm OS.

Calculations

For drug and lab calculations, I suggest MedCalc . This free program also runs under Palm OS, and is great for computing equations like predicted peak flow rate, pediatric fluid dosing, glomerular filtration rate, and pregnancy length. Specifying a particular area of practice, such as emergency medicine or pediatrics, can shorten the extensive list of available calculations to make it more manageable.

Review of Diseases

For a quick review of most common diseases, I recommend Griffith's 5 Minute Clinical Consult. This excellent program is indexed by disease name, medication, and ICD-9 code. Each entry contains basic information, diagnostic criteria (including differential diagnosis), treatment, medications used, follow-up required, and a miscellaneous category. This program's cost is currently listed as $64.95 and it is available in both Palm OS and Pocket PC versions.

Another useful program is PEPID. Originally written as an extensive information database for emergency physicians, PEPID now comes in several versions; each is tailored to the needs of physicians, medical students, nurses, and paramedics. This program is available by subscription, which means you pay a fee to use the software for a specified length of time (6, 12, or 24 months). After the time period has elapsed, you must renew your subscription to continue using the product. PEPID's Web site states that a 6-month subscription to PEPID-ED currently costs $69.95. The software is available for both Palm OS-based devices and Pocket PCs.

Some facilities are integrating the use of PDAs into their practice sites; this involves using PDAs as extensions of an integrated office-based computer system.^[3] These systems can include standard desktop PCs, network servers, printers, and fax machines. Within such a system, providers can download daily patient lists and appointment times to their PDAs at the start of the day; they can "write" prescriptions on the PDA and then beam them to a nearby printer, or even send the prescription to the office's fax machine, where it is sent to the patient's pharmacy. Nurses and healthcare providers coming on and going off duty or call can easily share the latest patient data by beaming their notes to each other during shift report.^[4]Patient Keeper, described above, has this beaming capability.

These are just some of the latest developments being implemented today. Considering the tremendous strides that have been made with personal computing in the past 20 years, it seems safe to assume that the PDA will be likewise be increasingly used as an adjunct in the provision of healthcare services. To paraphrase a recent technology commercial, "are you ready?"

1. Smart Computing Learning Series. PDA Tips, vol. 7, no. 7. Lincoln, NE: Sandhills Co; 2001.
2. Goggin T. The Mac user's guide to Pocket PCs. 2002. Available at:
   http://www.pocketmac.net/MacUsersGuideToPocketPCs.pdf. Accessed October 2, 2002.
3. Bergeron BP. Enterprise digital assistants: the progression of wireless clinical computing. J Med Pract Manag. 2002;17:229-233.
4. Luo J, Hales RE, Hilty D, Brennan C. Electronic sign-out using a personal digital assistant. Psychiatric Serv. 2001;52:173-174.

Andrew E. Craig, MSN, FNP, Doctor's Care, PA of South Carolina, Lugoff, South Carolina

Andrew E. Craig, MSN, FNP, has no significant financial interests to disclose.