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User Profile: HP Palmtop: A 24-Hour Medical Assistant
Dr. Meissner takes us through a very active day in the life of a Palmtop in the pocket of a Cardiologist.
"Thanks for calling back so promptly" the voice on the other end says. "I've got a `hot one' in the ER (emergency room), and I need your help in getting him into a CCU (cardiac care unit). I think he needs thrombolysis", the voice said somewhat timidly. Well, the current revolution in modern cardiology care, means that sleep is optional. Heart disease is the number one killer in America. You need to be prepared to respond decisively to patients with acute heart attacks and it does not matter whether it's day nor night.
In this case, the patient was at a 40 bed hospital an hour's drive from any of the hospitals with a CCU. Still at home, I discussed the situation with the Emergency Room physician and made treatment recommendations over the phone. The patient was a 45 year old male, smoker with hypertension and no previous history of heart attacks who came to the ER within one hour of his heart attack. Looking at his faxed EKG, he appears to be damaging the lateral wall of his heart. The physician did not have any reason to not treat with thrombolytic (clot lysis) therapy using streptokinase.
Ready Medical Reference
The physician I was assisting over the phone was at a small rural ER, and he had never given streptokinase before. It was also some time since I had used this agent, so I reached for my HP 100LX. A 40MB ACE DoubleCard installed in the A: drive, with a copy of ComputerBooks's Pharmaceuticals database, a DOS drug reference program which takes up about 4MB on the DoubleCard and costs $199.00 (see page 36, this issue of The HP Palmtop Paper, and my review of this program in Medical Software Reviews, October 1993).
I started the Palmtop, called up the program, found the streptokinase entry within one minute, and read the dosing protocol over the phone to the attending physician. The patients vital signs were stable and the heart attack did not seem to be extensive. I told the physician to begin therapy, and I'd call him back in a few minutes with a hospital that had an available CCU bed.
I switched to my phone book files and called a series of CCU's. I have admitting privileges in 5 hospitals in town and had to find an available bed in a Cardiac Care Unit. Before that call, I found the Life Flight number, briefed the aerovac crew on the patients situation, and sent them on their way to pick up the patient. I found a CCU bed and called back the ER. "Airlifes on the way, and he is to be admitted to St. Lukes", I said. "I'll meet him in the CCU, please call me when he leaves en route."
Calculating heart flow
At the CCU, I meet the patient, he is a 45 year old smoker with hypertension and no past history of MI, myocardial infarction (heart attack). I assess him at the bedside, and he has some mild rhales in both lower lobes of the lungs. This is a troubling finding in this setting, it suggests that he has a higher than usual chance of death during the current hospitalization. Therefore, I ask for a STAT echocardiogram. This technique allows me to `see' the heart using sound wave energy and to assess how large the infarct is and how likely it is that the patient is going to get into trouble later in the course of his heart attack. I take the basic ultrasound measurements and doppler echocardiography information, and then call up my echocardiography Solver file in the BUILT-IN HP Calc (ECHO.EQN<ON DISK ICON>). In a few moments I have an estimate of the patients cardiac output, stroke volume, ejection fraction and right ventricular pressure. These solver calculations using the echocardiography measurements allow me to judge the size and functional impact of this fresh heart attack. It helps me judge whether I'll need to scramble to the cardiac catheterization laboratory to do an acute catheterization. The infarct seems to be relatively small by echocardiographic criteria. So, I will continue to watch the patient through the night.
Keeping control of the details
Calling up the 100LX NoteTaker, I make an annotation of the patients name, hospital, and room number. I also note the fact that I had performed and interpreted an echocardiogram on the patient. This information is essential for the office staff in the morning with respect to billing information.
The next morning, I start making rounds; again, I call up the NoteTaker application and start to make my way from hospital to hospital. En route, I am beeped by my APPT alarm, I am notified to be at one of my hospitals to teach several students physical examination techniques. I swing by at the appropriate time, and start to teach them the finer points of cardiac physical examination. Fortunately for me, we are at the hospital at which I admitted my late night MI patient. We go to his bedside and examine him together.
I am rarely in the same place at the same time on any given day. The HP 100LX Appointment Book's improvements over this module in the 95LX have put my life back on schedule again. The display is aesthetically more pleasing, has more information visible (tiny calendar or clock next to the appointment or ToDo list) and has a more integrated feel to it than the 95LX version. The ToDo list is also an especially useful tool, as I usually have too many ToDo's in any given day or week. And I must admit in my mind, it is comforting to be able to check off and delete each small task of the day.
Use Lotus database to record examination findings
I notice a split S2 in the patient (second heart sound representing an aortic and pulmonary valve closure). I can't recall all of its causes, and once again my HP 100LX comes to my rescue.
One of the less utilized features of Lotus 1-2-3 is its database functions. I am developing a database containing cardiac physical examination findings. I will be able to call the list for reference in those times when things are incompletely remembered. I am in the process of developing a more extensive group of lists. This will allow me to develop a hypertext like system in which titles of lists will be displayed and linked by macro move commands to appropriate sub-listed regions of the spreadsheet.
Diagnosis assistant on the Palmtop
In the course of our conversation, the medical students mention a problem they are having with differential diagnosis. It concerns a patient with fever of unknown origin, THE classical problem of Internal Medicine differential diagnosis. I go to HP 100LX DOS and run Quick Medical Reference, a diagnostic expert system which requires 3.5MB of storage space and 640K of RAM memory (430K RAM free) to run (see Med Products, page 39 this issue). This is the most widely selling diagnostic expert system available for the DOS environment. It was recently reviewed in the Jan 94 issue of Medical Software Reviews. Using this program, and the historical information provided by the system, we begin to narrow down the diagnostic possibilities. This is a very difficult diagnostic problem and it is a real advantage to be able to run the program from this miniature medical informatics powerhouse. The students now have some leads as to where to start on the case, and they leave, ready to pursue a number of promising possibilities.
Using Solver for catheterization problems
I get to the office and transfer the information concerning the multiple admissions I had made over the weekend. I call up my appointment calendar, and start to work my way through the outpatients on the days schedule. I maintain a separate patient phone book, so that I can maintain phone files of patients independent of my ICU/ward numbers.
I also train cardiology fellows in cardiac catheterization techniques. The trainee and I need to perform the calculations involved in hemodynamic cardiac catheterization procedures. Probably no field of medicine except perhaps radiation oncology, has as many calculations and mathematical relationships within it as does Cardiology. So, in this world of flows and pressures, resistance's and indices; the Solver is an invaluable tool.
I have my machine set up to accomplish major cardiac catheterization calculations. As I have previously mentioned, I have another separate solver calculation file for echocardiography calculations (ECHO.EQN <ON DISK ICON>). I maintain separate equation files for ease of use. It is rare to need calculations from the cardiac catheterization list (CATH.EQN <ON DISK ICON>) within the echocardiography laboratory. So, for repetitive calculations it is easy to simply open the appropriate Solver list and crunch numbers.
In addition, I can use Solver to assess in a graphic way the improvement of one of my critically ill patients cardiac function. I take several sets of hemodynamic parameters, and plot a curve of left ventricular filling pressure (as estimated by the pulmonary capillary occlusion pressure) versus the cardiac output.
Database for tracking procedures
As a procedural oriented specialist, I find it increasingly important to keep track of procedures. Consequently, I have developed a 100LX Data Base module (PROC.GDB <ON DISK ICON>) which tracks my procedures by type, linking them with a unique patient ID and detailing any complications of the procedure. I have a free form Notes field in the database for additional information. This is an invaluable resource for credentialing, as everyone now is very interested in how many procedures and of what types one has performed.
Searching the world for the latest information
Just before resuming rounds, I receive a frantic phone call from a telemetry ward (this is a unit in which all patients are on heart monitors, but they do not require mechanical ventilators). One of my patients has had an unusual arrhythmia (heart rhythm abnormality), "torsades de pointes". The most common cause of this abnormality is due to a medication effect. I review the patients medication list and see no potentially incriminating agents. However, my psychiatry consultant has recommended and started the patient on one of the newer antidepressant agents, Zoloft (sertraline). Many of the older antidepressant agents have been implicated as causes of torsades, so this is worth investigating.
I remove my 40MB ACE card, insert an X-jack Megahertz 14.4 Modem card, connect with my local medical school computer account and log on. A search for references combining torsades de pointes or ventricular tachycardia vs. sertraline finds nothing. I go to the MicroMedex section of this library system, I select the drug description database and search the Zoloft entry. No torsades as a reported side effect. However, I do find a reference to one patient who demonstrated QT interval (the QT interval is the period of time demonstrated by the EKG from the end of the Q wave to the beginning of T wave) prolongation with the drug. This is a common finding in patients who subsequently develop torsades.
I exit the library information system and return to the system prompt. From here, I log on to the FDA (Federal Drug Administration) bulletin board (fdabbs.fda.gov), an Internet accessible resource sponsored by the FDA. I search here for all Zoloft references, but still no mention of torsades. Next I log on to BRS Colleague, a commercial service dedicated to health care and the biological sciences. I search this database with no luck. I go to MindVox (phantom.com), an inexpensive commercial information service. It has an excellent world wide web browser with a large number of medical resources. I go to the NIH Clinical Alerts and there is no information concerning torsades in Zoloft. No other databases seem appropriate in the web, so I log off.
The search was negative, but valuable in that I am reassured that the patients underlying heart disease is most likely responsible for his arrhythmia. However, the QT prolongation reference is an important piece of the puzzle. Not enough here to discontinue the drug, but I do call my psychiatry consultant and ask him to reconsider therapy and perhaps suggest a different agent.
The ability to do online data searches to a world wide web of users, information, and specialized medical databases, is of enormous practical advantage in today's fast paced medical practice. Knowledge is not only power, timely information is lifesaving and database searching is a fundamental skill for today's physicians.
Realistic risk assessment
I've a patient in the cardiac catheterization laboratory. He is a typical patient, in that there is nothing typical about him. Much is said about the "over-utilization" of coronary artery surgery in American Medical practice. The reality is that the decision to recommend bypass is a highly individualized decision for every patient.
This patient has severe aortic valve regurgitation and depressed function of the left ventricle. One of the things that all patients wish to know is "how likely am I too die in cardiac surgery?" This is an understandable concern, and one previously extremely difficult to assess in any scientifically valid way.
My global HP 100LX strategy is to maximize RAM memory by utilizing the ROM applications built into the HP and minimizing on-board programs. However, I have recently started utilizing the program RiskMaster (see Med Products, page 39). This program which calculates the risk of death during bypass surgery once a large group of clinical variables are entered into the computer. It is incredibly useful and really streamlines and standardizes the risk calculations for patients. The tool is derived from the results of 20 separate surgical groups over a 6 year period and is based on 60,000 surgical cases.
Thus, the estimate of probability of death is quite defensible. The alternative is to try and make an educated guess from your own experience. The problem is that you may only encounter some situations one or two times in your professional career. This program is with me at all times, because this is one of the commonest and most important decisions I make. The patient and I discuss the ramifications of the decision and (s)he chooses from a stronger basis in fact than was previously available to me before obtaining this program.
Mastering clinical calculations
When I was an Intern, the hottest thing going, was the HP-15C scientific calculator (which I still have and use). I had programmed mine to do a lot of the repetitive calculation tasks that the non-computer literate interns did by hand. Because of this experience, I had several years ago developed an Excel spreadsheet that did every calculation that I could imagine or find for clinical medicine. When I got my HP 95LX, I translated the spreadsheet into a 1-2-3 compatible format and ported it to my Palmtop.
When my 100LX came along, my 5 year old spreadsheet easily made the transition (CLINICAL.WK1 <ON DISK ICON>). It is useful to pull up the spreadsheet, enter lab values, calculate the spreadsheet and have all the numbers `sweated' for you, automatically in the blink of the non-Cyber eye. It impresses my colleagues; the ease with which I am able to provide them with the answers to many of their acid base and electrolyte problems based on the spreadsheets calculations.
I am en route to a medical conference. And as we all know airline trips are not completely fun. A lot of time was wasted during the trips, UNTIL, the HP 100LX entered my life. Personally, I have problems using any laptop machine on airlines, since the seats are poorly designed for the laptops themselves. However, the 100LX is optimized for airline flights.
I have to design a lecture for house staff (doctors in internship and residency). I use the Outline function in MEMO to develop a text outline for my slides. Each major heading will represent a slide title and each sub-heading a line of text for the slide. I've been teaching for quite some number of years now, and the general rules of six lines per slide and six words per line are not only good rules, but easily adhered to with the HP's basic text program.
Making connections with Mac, CompuServe and the world
I am a dedicated Mac user, and all my desktop presentation software and equipment is Macintosh based. Fortunately, the slide files I create on the 100LX are easily moved using an HP Connectivity Cable (F1016A) and MacKermit <ON DISK ICON>, a download from the Macintosh Communications forum (GO MACCOM) on CompuServe. I also have an Omnibook300 with an external 3.5" disk drive and an ACE Double Card that I use to transfer data from 3.5" disks to the 100LX. I save or move the data to the Ace card, insert the card in the OmniBook's A: slot, transfer the file to an IBM disk and insert the disk in my Powerbook180, which reads PC disks.
I get a beeper page and am told that I need to fax my Curriculum Vitae (resume) to California. I always have a copy of this document available, stored in my CompuServe Information Services mailbox. I had mailed a copy of it to myself some time ago. I keep it in my mailbox as a permanent document. I call my CIS account using my 100LX and the X-Jack 14.4 modem again, connect, go to the mail system and forward the Curriculum Vitae to California via the FAX CompuServe mail option. CompuServe allows users to Fax to United States phone numbers for $.75/fax page. I still have this vital capability without burning precious internal RAM memory or using a dedicated FAX modem, which operates at data speeds too slow for my tastes or telecomm needs.
I then connect to CompuServe's MedSig forum, where I am the primary sysop (system operator). We are currently running in excess of 300 messages a day, and about 3-4 library uploads a day. I start to scan my new message files. I am using the plain vanilla access to CIS, provided by DataComm but of no matter, forum sysop functions can only be executed in terminal mode, and nothing is faster for reading and responding to the message base. I start to read the messages, fingers flying as I struggle to keep up with the very detailed, thoughtful, and insightful posts that my colleagues and layman post on what I immodestly believe to be the most fascinating piece of cyberspace, (next to CompuServe's HP Hand forum, of course).
Electronic genie keeps it all together
I've tried to give you a sense of how this "electronic genie" serves me in the course of my practice. The multitude of places I must be at and the things I must do, the sometimes bewildering amount of facts and priorities in my life, had made my life almost unmanageable. The HP Palmtop keeps me on time, under budget, and free of carpal tunnel syndrome (I personally think it is harder to get carpal tunnel syndrome from this box than, for example, my Powerbook 180).
The future? I hear they are about to release a messaging/paging card to put in the HP 100LX. (See HP Starlink, pages 5 and 13, Mar/Apr 94 issue and Access card, page 6 this issue). I can only wish for the day when such a card could incorporate my beeper and intelligently answer routine questions. Maybe I'd get some sleep then!
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