Acknowledgments:The author reports no financial, academic, or other support of this work. 



What are the potential uses for personal digital assistants or handheld computers in the practice of medicine? Pagers and cellular phones are mainstays in the practice of medicine to access and communicate information, but an electronic version of a day planner appears not to be a valuable tool to most physicians. With the increasing hardware capabilities of these handheld devices, more software has been developed for clinical purposes such as drug references, prescription writing, medical record keeping, and charge capture. After reviewing the different medical applications available for the handheld device, most physicians will find many compelling reasons to adopt this new technology.



The practice of medicine has increasingly become more dependent on computer technology. Computer terminals provide access to laboratory results, and personal computers facilitate note writing. The facsimile machine eliminates dependence on couriers and mail for document exchange. Pagers were the first devices that allowed physicians to roam from the office yet still remain available for urgent contact. The cellular phone extends this availability by eliminating the time required to locate a phone. In this progression to increasing dependence on technology, personal digital assistants (PDAs) have quickly become an essential tool in the practice of medicine. A recent article discussed how the use of PDAs may improve patient safety and decrease medication errors.1 The Agency for Healthcare Research and Quality has funded four research projects involving PDAs to prevent medical errors.2 This article focuses on the different ways that a PDA can assist primary care physicians in the care of their patients.

Background and Basics

PDAs first appeared in the 1990s primarily as electronic versions of their paper-based cousins the day planner or personal information manager. Functions of the PDA included a calendar, an address book, a to-do list, and a memo area for notes. All of these features worked similarly to paper-based organizers, but the screen size was small and text entry was cumbersome. Backup of information was quite limited because the cables and software for desktop computer connection often cost more than the device itself. An obvious advantage of the PDA is that the entries are in machine text, which is legible, but the early PDAs were not exchangeable with other devices. Today’s PDAs have improved capabilities such as larger screens and improved input, but what sets these devices apart from paper organizers is their capability to run additional programs or medical applications.

There are many other advantages to using PDAs. A key element involves their form factor—their size varies from a pack of cards to a thick checkbook. For the busy physician moving from the office to the hospital or even between examination rooms, this small form factor provides great portability and function. Almost all PDAs provide some linkage to information on desktop computers. This capability allows synchronization of data on the PDA and on the desktop computer to keep information current. In addition, this synchronization process serves as a crucial backup feature when data are lost.

One common concern is that a “computer illiterate” physician will not be able to use a PDA. In actuality, using a PDA is much simpler than operating a desktop computer. The user interface is quite friendly and intuitive, and no typing skills are really necessary. All functions can be accessed with a push of a button or a tap on the screen. In fact, taps on the screen with the stylus are the primary way that the different functions of the software programs are accessed. To learn how to install programs and maximize productivity, many physicians attend classes that are offered by local medical societies, read books on PDA use (Table 1), or seek information on the Internet (Table 2).


Choosing a Personal Digital Assistant

Choosing a PDA is really a simple matter despite the somewhat daunting variety of models and manufacturers. It is important to note that because technology improves and changes rather quickly. Newer models that may offer additional features or desirable capabilities appear almost every quarter. Waiting for prices to drop is one strategy, but in doing so you will not benefit from the many capabilities that these devices offer, as described in this article. A good plan of action is to consider keeping your PDA for at least a year, and then upgrade only when new features are compelling, such as more memory or wireless capability.


Which PDA to purchase should be determined first on the basis of its operating system (OS). Currently, four main kinds are available: Palm OS–based PDAs, which are at present the most popular worldwide; EPOC OS–based PDAs, which are more popular in Europe; Pocket PC–based PDAs, which are gaining increasing market share; and Linux OS–based PDAs, which have just begun to enter the market. Generally, all PDAs have similar basic capabilities, but what sets them apart are available software, hardware features, and accessories.

Palm OS ( PDAs are the most popular because they are quite quick and portable. They are generally smaller than their counterparts, noted for an “instant-on” capability, intuitive user interface, and good battery life. The available general and medical software for the Palm OS is the largest of the four operating systems. In addition, many hardware accessories are available such as external memory, modems, keyboards, Bluetooth, and wireless local area network (LAN) adapters. Manufacturers to consider include Palm, IBM, Sony, HandEra, Acer, and Handspring (Table 3). Newer devices based on Palm OS 5 due in the latter half of 2002 will be faster, multitasking, and will have built-in security and Web-browsing capability.


Pocket PC–based PDAs ( are considered the powerhouses of the PDA market with more memory and a faster central processing unit. These devices are noted for enterprise-level capability but are notorious for a poor battery life of ~1 day. A significant advantage of devices based on the Pocket PC OS is that exchange of documents with Microsoft Office on the desktop computer is easier. Although the number of software developers for the Pocket PC is significantly smaller than for the Palm OS, this trend is slowly beginning to change. Manufacturers include Toshiba, Compaq, Hewlett-Packard, Casio, Urthere, Audiovox, and NEC.

EPOC OS and Linux OS are both quite capable PDAs and, from a technological standpoint, are worth consideration. However, both of these PDAs lack a significant software developer base. Psion (, one of the primary manufacturers of EPOC OS PDAs, has withdrawn from the consumer market in order to focus on enterprise and vertical markets. Linux OS PDAs by Agenda(, Samsung (, and Sharp ( are quite feature rich but should only be used by those comfortable with the Linux OS. Although the Opensource software community is writing and porting (converting) more software for the Linux OS PDAs, physicians using these devices should be prepared for limited selection and some confusion regarding compatibility of software owing to different installation packages.

General Use

The basic capabilities of PDAs work well for most physicians and can be well adapted for medical purposes. These programs are called read-only memory (ROM)–based programs, because they are permanently located in the PDA’s memory. By comparison, any additional software program installed will be located in random access memory (RAM). This type of memory is not permanent, and information residing in RAM can be erased as needed. The more RAM that a PDA has the more programs, as well as information, can be stored.

An advantage to the calendar program is the ability to set repeating appointments which prevents double booking. For example, patients who are extremely needy and call for appointments frequently, can schedule for regular visits. The address book program is quite versatile in storing not only patient demographic information, but also other important information such as preferred pharmacy or medical record number. The to-do program provides an obvious mechanism to keep track of activities such as returned calls and prescription refills. It has the capacity to record the date of the action completion, which may help with medical record documentation. The memo or note program in the PDA is very useful for entering short notes such as drug information or a brief synopsis of symptoms for diseases.

In the Palm OS PDAs, only short notes can be entered because of the 4-kilobyte file-size limit, which represents ~<1 full page. More extensive text editing is available on Palm OS PDAs with software such as QuickWord ( or Wordsmith ( These programs offer conversions between Microsoft Word and the Palm PDA versions of the document. On Pocket PC devices, there is no size limit because Pocket Word is a standard application with linked conversion to documents on the desktop. Documents can be printed with the use of additional infrared or wireless printing software specific to the PDA.

E-mail is an increasingly more popular medium for physicians to communicate with their patients. However, the small screen and relative inability to work with attachments limit E-mail on the PDA. E-mail can be handled either with direct PDA Internet connection such as a modem or through synchronization with an Internet-connected computer. Drawbacks to electronic communication with patients include security and timeliness of response. A policy regarding E-mail communication is advised with clear expectations regarding content, response time, copies to the paper chart, and mechanisms for emergencies.3 For an extensive list of Palm OS E-mail software, visit Handheld Computing magazine’s Web site ( or check PalmGear ( and search the links for E-mail software. Although the Pocket PC includes Pocket Outlook for E-mail, PocketGear ( has additional related software that adds more features.

Medical Software

Drug Reference

Drug information at the point of care is one of the most valuable uses of a PDA (Table 4). Programs that supply such information cannot replace resources such as the Physician’s Desk Reference4(, but they do provide concise content that is extremely portable. Reviews of programs such as ePocrates qRx ( have reached publications such as the Journal of the American Medical Association, elevating their status on par with medical texts.5 A significant advantage is that many of these programs link to other programs that will check for drug-drug interactions or have this capability built in. This capability is important to physicians who prescribe antidepressant medications, in particular owing to the cytochrome P450 enzyme inhibition of selective serotonin reuptake inhibitors. Several years ago, such drug interaction software was not available, and lists of drug information tables stored in memos were the only way to determine potential problems. This mechanism was rather cumbersome and time-consuming, especially for patients who were taking more than four medications. With the use of programs such as MultiCheck, which is available as part of ePocrates qRx, drug interactions are calculated with a few screen taps to select the medications in question and then cross-checked automatically. Additionally, medications can be selectively added or deleted from the list and cross-checked again.


Prescription Writing

Prescription writing is a mainstay of medical practice, and PDAs serve an extremely useful function in this area. Software is available to generate legible prescriptions, which will decrease potential transcription errors at the pharmacy (Table 5). For example, a recent notice from AstraZeneca was sent to physicians warning about reported errors between prescriptions filled for quetiapine (Seroquel) and nefazodone (Serzone), due to the similar trade names. Many programs print the prescription on specialized paper or with specialized printers. In addition, some programs such as Iscribe 5000 ( allow the physician to send the prescription electronically to pharmacies via fax from the desktop computer or by wireless via company servers, as in the case of Ephysician ( Another advantage of handheld prescription writing is that the software can check for availability of the medication on the health plan formulary. By doing so on the handheld device before printing the prescription, the physician will be alerted when a treatment authorization request must be done. Patients find this capability extremely helpful because it eliminates the need to call their health plan or the physician’s office.


Reference Texts

Psychiatrists rely on reference texts such as the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR)6 or the American Psychiatric Press Textbook of Psychiatry.7 Only a few reference texts for psychiatry are now available in electronic form for review on the PDA (Table 6). There are numerous general and specialty medical texts such as the Merck Manual,8 5 Minute Clinical Consult Series,9 Harrison’s Principles of Internal Medicine Handbook,10 and DeGowin & DeGowin’s Diagnostic Examination11 that are available in Pocket PC and Palm OS formats from Handheldmed( and PDAMD ( The primary drawback to reading these reference materials is the small screen and memory availability in certain handheld devices.


Diagnosis Assistants

The diagnosis of mental disorders is based on matching symptoms to criteria listed in the DSM-IV-TR. For the sake of portability, many people have modified an electronic version of reference texts for the desktop and converted the information for the PDA. DSM-IV-TR diagnosis codes and disease criteria for the PDA are available on the Internet in a variety of software program formats. Good resources for this software on the Palm OS are PocketPsych ( and Memoware ( Medical Piloteer ( sells a program called PsychDx that has the DSM-IV-TR criteria summarized and presented in a structured program versus reading a rather static document file. For specific assistance in diagnosis of different mental disorders, the available software is rather limited. Medical Piloteer offers DepressQ and ManiaQ, which are checklist-based programs to assist in the diagnosis of mood disorders for the Palm OS. On the Pocket PC side, there are no specific mental disorder diagnosis programs, but DiagnosisPro from Medtech ( offers differential diagnoses based on different sign and symptom entries.

Treatment Guides

Available psychiatric treatment guides include the American Psychiatric Association Treatment Guidelines, a comprehensive treatment resource available from Handheldmed. However, it does not lend itself for quick navigation. For primary care physicians who need quick and easy-to-navigate information on the treatment of mental disorders, Compendica ( has an excellent reference product, but only for the Palm OS. In addition, Medical Piloteer’s PsychRx has summarized treatment recommendations.

Medical Calculators

Medical calculators are available to assist the physician with determining parameters such as body mass index, absolute neutrophil count, and corrected blood volume, among many others (Table 7). Medcalc ( desc.html) is a well-known calculator that is available free of charge, but only in the Palm OS. James Suliburk of Handheldmed has written a summary of reviews for many medical calculator programs for the Palm OS ( newsmore.php?NID=262 &DETAIL=). For the Pocket PC, MedicalPocketPC provides an overview of the available calculator software ( In psychiatry, the primary “calculation” is the Mini-Mental State Exam. There are a variety of software programs to assist in carrying out and scoring the examination (Table 8); however, they currently only exist for the Palm OS.


Patient Tracking

Patient tracking can be done on the PDA using either the to-do feature or specific software (Table 9). Although many programs exist, even those for mental health purposes, such as the Virtual-Briefcase, organization of patient care information is a matter of preference. Some of the programs listed in Table 9 have integrated features such as charge capture and coding. Programs such as HandDBase ( allow users to create specific databases to fit their needs or purchase databases designed for mental health practitioners. Patient Keeper, Patient Tracker, and Ward Watch are specialized programs to store patient information. These are ideal for primary care physicians.



Billing and Coding

Charge capture is part of the practice of medicine, and PDAs can help with the billing and coding. Numerous programs are available (Table 10), such as PocketBilling and Pocket Patient Billing. These programs allow physicians to document evaluation and management (E&M) charges, Current Procedural Terminology codes, procedures, and patient visits. A very useful program is STAT E&M Coder (, which has evaluation and management algorithms to determine the proper E&M code for the office visit. Zapmed ( and e-MDs ( have similar products as well. Many of these companies have products that link to each other as well as to programs on the desktop computer.



Because of the PDA’s portability, security measures must be taken into account, especially in light of sensitive mental health information. The Health Information Portability and Accountability Act (HIPAA) of 1996 was developed to improve the efficiency and effectiveness of electronic information, but many physicians know it as the legislation that mandates protection for health information beginning in 2003. The HIPAA specifies that all providers who conduct electronic billing directly or via clearinghouses must implement security in these transactions to maintain the privacy of an individual’s medical record. Because of the possibility of theft, information in electronic form on the PDA is quite vulnerable. Although the HIPAA does not specify the security mechanism to be used, the best mechanism for security on the PDA is to use encryption software.12 Such software programs (Table 11) require the correct password to access the device as well as to decrypt the data for viewing. Some of the programs will delete all information on the device after a user-defined number of trials, which may be indicative of improper access.



The numerous medical capabilities of PDAs described are applicable to the individual physician or a particular service in the hospital. Additional hardware, such as a keyboard or extra memory, expand the capabilities of these devices even further (Table 12). For example, PDAs in consultation psychiatry13 at the University of California, Davis Medical Center in Sacramento,  have been involved in document editing with software and portable keyboards, accessing drug references, checking DSM-IV diagnostic criteria, determining proper DSM-IV diagnosis coding, and providing electronic sign-out to weekend staff.14 PDAs have been used to decrease medication error rate and have been beneficial in meeting regulatory requirements of the Joint Commission on Accreditation of Healthcare Organizations survey.15 As these devices gain more hardware capabilities such as expansion cards and faster central processing units, new software will provide more assistance to the provision medical care in ways such as remote information access via wireless networks. Newer devices such as the OQO ultra–personal computer ( and the Tiqit eightythree ( will further push the boundary of desktop computing devices in a handheld form factor. Eventually, the desktop computer will be a historic memory in the practice of medicine. PP



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