Brain stem mapping: neurophysiological localization of motor nuclei on the floor of the fourth ventricle.

We have improved upon a brain stem mapping technique that can be used to locate cranial motor nuclei on the floor of the fourth ventricle. This technique helped to intraoperatively locate the facial colliculus and the motor nuclei of cranial nerves IX/X and XII in 14 patients undergoing removal of brain stem tumors. The motor nuclei of these cranial nerves are usually located relative to specific anatomic landmarks on the ventricular floor. These landmarks were not evident in most patients studied because of the distorting effects of the tumor. Different points of the floor of the fourth ventricle were electrically stimulated while electromyographic responses were recorded with electrodes inserted in the orbicularis oculi and orbicularis oris muscles, the lateral posterior pharyngeal wall, and the intrinsic muscles of tongue. Mapping was performed before and after tumor resection. The technique was found to be useful for locating cranial motor nuclei before tumor resection. It enabled surgeons to avoid damaging the nuclei when entering the brain stem. This technique, however, has certain limitations. Because this is a mapping technique, not a monitoring technique, continuous monitoring during tumor resection was unavailable. Also, the presence of a muscle response after tumor resection did not always indicate preservation of immediate postoperative function (7 days after surgery) because damage to the corticobulbar tract and/or the underlying neural circuitry was not detectable by mapping. Further research is needed to determine the point of stimulation in the functional motor circuitry and the relationship between intraoperative recordings and postoperative function in the long term.

Intravenous fluid therapy in neurologic injury.

Cerebral autoregulation and the blood-brain barrier are two important mechanisms that attempt to preserve brain homeostasis. The function of either may be disrupted by injury. When autoregulation is impaired, blood pressure and hematocrit determine cerebral oxygen delivery. Injury to the blood-brain barrier impairs brain volume regulation and may contribute to cerebral edema. The choice of intravenous fluid influences cerebral blood flow, cerebral oxygen delivery, brain metabolism, and brain volume.

Information systems and multimedia as educational tools.

Electronic publication uses video, sounds, and pictures to present some ideas (e.g. characteristics of a heart murmur) that may be difficult to convey with printed text, and is changing the way in which physicians communicate.

The Internet and medicine: past, present, and future.

The enormous growth of the Internet and the World Wide Web has made these two technologies an important potential adjunct to cost-effective health care research and delivery. This article surveys some recent developments in telecommunications, networking and artificial intelligence that are likely to have a significant impact on improving the efficiency and quality of future health care. Issues discussed include: clinical record keeping on the Internet, Internet-assisted medical diagnosis, privacy and security matters, financial transactions, digital money, bandwidth concerns, multimedia (music, audio and video) information delivery via the Internet, intellectual property, and the concept of Information Philanthropy.

Development of an academic Internet resource.

Networked electronic publication is a relatively new development that has already begun to change the way in which medical information is exchanged. Electronic publications can present ideas that would be impossible in printed text, using multimedia components such as sound and movies. Physicians who use the World Wide Web (WWW) on a regular basis may recognize the value of electronic publication and decide to become information providers. Nearly anyone with a computer and modem can create a WWW resource on a Web server at a hospital or on a commercial hosting service. Medical publication on the Internet demands a high level of quality control because the information will be available to anyone who cares to look. Creating a peer-review system for electronic information may, therefore, help to enhance academic recognition of Internet medical resources. Resources containing medical information must be continually available and protected from system failures and unauthorized access. As Internet technology matures and these problems are solved, electronic publication may become the predominant method of communication between medical professionals.

Internet teleconferencing as a clinical tool for anesthesiologists.

Internet teleconferencing software can be used to hold "virtual" meetings, during which participants around the world can share ideas. A core group of anesthetic medical practitioners, largely consisting of the Society for Advanced Telecommunications in Anesthesia (SATA), has begun to hold regularly scheduled "virtual grand rounds." This paper examines currently available software and offers impressions of our own early experiences with this technology. Two teleconferencing systems have been used: White Pine Software CU-SeeMe and Microsoft NetMeeting. While both provided acceptable results, each had specific advantages and disadvantages. CU-SeeMe is easier to use when conferences include more than two participants. NetMeeting provides higher quality audio and video signals under crowded network conditions, and is better for conferences with only two participants. While some effort is necessary to get these teleconferencing systems to work well, we have been using desktop conferencing for six months to hold virtual Internet meetings. The sound and video images produced by Internet teleconferencing software are inferior to dedicated point-to-point teleconferencing systems. However, low cost, wide availability, and ease of use make this technology a potentially valuable tool for clinicians and researchers.

Medical computing over the World Wide Web: use of forms and CGI scripts for constructing medical algorithm Web pages.

The development of the World Wide Web has led to an explosion of educational and clinical resources available via the Internet with minimal effort or special training. However, most of these Web pages contain only static information; few offer dynamic information shaped around clinical or laboratory test findings. In this report we show how this goal can be achieved with the design and construction of Medical Algorithm Web Pages (MAWP). Specifically, using Internet technologies known as forms and CGI scripts we demonstrate how one can implement medical algorithms remotely over the Internet's World Wide Web. To use a MAWP, one enters the URL for the site and then enters information according to the instructions presented there, usually by entering numbers and other information into fields displayed on screen. When all the data is entered, the user clicks on the SUBMIT icon, resulting in a new Web page being constructed "on-the-fly" containing diagnostic calculations and other information pertinent to the patient's clinical management. Four sample applications are presented in detail to illustrate the concept of a Medical Algorithm Web page: Computation of the alveolar-arterial oxygen tension difference using the alveolar gas equation; Computation of renal creatinine clearance; drug infusion calculation (micrograms/kilogram/minute); Computation of the renal failure index.

WCALive: broadcasting a major medical conference on the Internet.

Live video and sound from the 11th World Congress of Anaesthesiology in Sydney, Australia were broadcast over the Internet using the CuSeeme software package as part of an ongoing evaluation of Internet-based telecommunication in the delivery of Continuing Medical Education (CME). This was the first time such a broadcast had been attempted from a medical convention. The broadcast lasted for four days, during which a functioning combination of computer hardware and software was established. Technical issues relating to broadcast of these real time signals over ISDN links and the Internet itself were addressed. Over 200 anaesthetists from around the world were able to 'attend' the plenary sessions via the Internet. Evidenced by feedback received audio reception was quite good. Video reception was less successful for those receiving the broadcast via a modem based Internet connection. The received signal in such circumstances was adequate to provide a video presence of the speaker but inadequate to allow details of 35 mm slides to be visualised. We conclude that this technology will be of use in the delivery of CME materials to remote areas provided simultaneous viewing of high resolution still images is possible using another medium, such as the World Wide Web.