From its containment in a simple rubber gasbag to its application via sophisticated computer-controlled circuitry, anesthesia and the systems that administer it have come a long way. But just what makes for a cutting-edge anesthesia system? Are design and technology true advances or the equivalent of chrome on metal? And what do these complicated systems mean for those charged with keeping them in working order?
A biomed performs diagnostics on a Datex-Ohmeda patient moniter.
Anesthesia by inhalation has come a long way since the days of Horace Wells, recognized in 1864 by the American Dental Association and in 1872 by the American Medical Association as the discoverer of anesthesia for his work with nitrous oxide. From its containment in a simple rubber gasbag to its application via sophisticated computer-controlled circuitry, anesthesia and the systems that administer it have proved invaluable in the progress of dental and surgical healthcare.
Many healthcare institutions forever mindful of patient-safety issues choose to invest in what they believe are state-of-the-art, top-of-the-line anesthesia systems.
But just what makes for a cutting-edge anesthesia system? Are newfangled design and the latest technology true advances or the equivalent of chrome on metal? And what do these complicated, contemporary systems mean for the men and women who have to keep them in peak performing condition?
As a general rule, systems of any nature considered sophisticated enough to earn the state-of-the-art label are those designed to provide the user with the best quality possible.
Todays state-of-the-art anesthesia system is one which supports current clinical practice and the process redesign activities that are increasingly required to remain competitive, explains Robert Clark, business manager, Anesthesia Systems, Dräger Medical Inc. (Telford, Pa.). Supporting workflow by reducing turnover times, providing flexibility for scheduling by having universal ventilation capabilities, and being able to transfer the patient without having to use an extra transportable monitor all contribute to the goal of the anesthesia system becoming transparent within the process. To be truly state of the art, the system should be designed to be able to be upgraded in an effort to meet future clinical practice and process needs, thus protecting the hospitals investment.
Dan Alt, senior project engineer, Health Devices Group, ECRI, (Plymouth Meeting, Pa.), believes that state-of-the-art anesthesia systems are those that provide support to a wide range of patients utilizing an assortment of automatic modes and are accurate when delivering low-flow anesthesia.
Automatic alarm and error logs are a must, and automatic anesthesia record keeping is a plus, begins Alt. Automatic self-checks at start-up while not a replacement for user checks are both common and useful. Safety features, such as a backup battery that powers both the gas platform and the monitors are mandatory.
For some, a true state-of-the-art system provides clinicians with more information than ever before, more easily and more quickly, enabling better patient care.
The system will have sophisticated ventilation modalities, including volume control ventilation (VCV), pressure control ventilation (PCV), pressure support ventilation (PSV) and synchronized intermittent mechanical ventilation (SIMV), asserts Ben Logterman, marketing, Anesthesia Care, Datex-Ohmeda (Madison, Wis.), a division of Instrumentarium. The ventilation information will be accessible on the monitor screen, along with information on hemodynamics, neuromuscular block status and some means to indicate depth of anesthesia. Finally, the monitor will be connected to an information management system, or be information-ready to accurately and quickly record vital data.
The haves and the have-nots
Determining whether or not an anesthesia system can be labeled state of the art is relatively simple, according to Logterman. He says that a quick appraisal of a systems ventilation modalities, monitored parameters and information management capability renders that conclusion.
Clark, of Dräger Medical, agrees.
Firstly, does the anesthesia system support the current clinical practice and offer universal patient care? he asks. Is the system able to be upgraded to add additional capabilities at a reasonable cost? Is the underlying technology employed capable of supporting the emergence of clinical information systems by providing all measured data such as fresh gas flow electronically for inclusion in the patient record and for cost and quality management?
While concentrating on the features a system has is a good start, another good test is to consider what features it doesnt have.
Nonstate-of-the-art systems generally lack the SIMV mode and much in the way of automation, Alt points out. They also may have little or no integrated monitoring. New units generally have at least gas and agent monitoring included. Overall, though, the best way to determine the technical capability of a unit is through [putting it on trial], not merely looking at it.
Technology marches on
The ventilation capabilities of anesthesia systems have grown by leaps and bounds as the technology to make more things possible also has advanced.
Modern anesthesia systems offer advanced piston-driven ventilators capable of delivering accurate volumes to all patient groups. The anesthesia workstation has matured, with optimized ergonomics designed to reduce errors and improve patient care, Clark assesses.
Healthcare economics have helped to drive awareness of the anesthetic agent usage and how it can be reduced with low-flow anesthesia techniques, he opines. The device manufacturers have actively supported this shift in practice with the introduction of fresh gas decoupling, warmed breathing systems and on-line user help, he says.
The other significant development is the change in materials and technologies that has allowed manufacturers to reduce the maintenance cycles for the anesthesia systems, he adds, thus reducing disruption and cost of ownership. This is enhanced by recent developments in the field of remote diagnostics.
ECRIs Alt indicates that simpler, less-comprehensive anesthesia units are finding a place in outpatient clinics and surgical centers as the number of procedures performed outside the hospital increases. Although he acknowledges that the depth-of-anesthesia monitoring issue has received a lot of attention recently, Alt doesnt expect a consensus in terms of that particular monitorings importance in the operating room (OR).
With peoples reactions ranging from what he describes as enthusiastic to dismissive, Alt says he has not seen the evidence to suggest that the level of consciousness monitoring provides the clear-cut benefits claimed by manufacturers. Physiologic monitoring and gas/anesthesia monitoring are standards of care, he notes, while level-of-consciousness monitoring, or depth-of-anesthesia monitoring, is not.
Increased integration of physiologic monitoring over the last decade helps present a clearer picture of the patients condition, he says. Increased integration with monitoring and automatic record-keeping outside the OR may well be a goal of manufacturers in the near future. Overall, though, the technology is fairly mature and the performance of the basic components of the systems, such as the ventilator and the vaporizer, has changed little.
In the last decade, the addition of microprocessors in anesthesia ventilators has allowed for the introduction of the more sophisticated modes normally reserved for Intensive Care Units (ICUs). Logterman relates that clinicians need this information in the OR in order to properly anesthetize high-acuity patients requiring invasive procedures.
More recently as costs have dropped, color screens that allow better differentiation of multiple monitored parameters on a single screen have become standard, he says. Also, computer technology has dramatically improved efficiency by providing information management systems throughout the hospital and at specific point-of-care locations, such as the OR.
Actions speak louder than words
The value of any anesthesia system can only be truly measured by its ability to perform its function, Clark reiterates. Anesthesia systems provide life support functions during surgery. The ability to provide this life support for all patient groups under all clinical conditions is the true test of the system.
A system that monitors the parameters and provides the ventilation sophistication needed by the patients at that anesthetizing site will be considered to be of value. The system will encourage lower fresh gas flows to conserve cost, protect the environment and add to patient comfort and rapid turnover of the anesthetizing site, Logterman says.
[The true value of an anesthesia system is found] in its ability to safely support as wide a range of patients and procedures possible, thereby reducing the need for other models, says Alt, who also advises that standardization on as few models as possible increases the hospitals bargaining power and helps reduce user confusion.
Life support for anesthesia systems
Everything on an anesthesia system that comes into contact with the user is vulnerable, as with any other piece of biomedical equipment. Parts that can be used as a handle are especially vulnerable to damage or breakage, Clark remarks.
Leaks in the vaporizers and absorbers are not uncommon, according to Alt, while Deb Schmaling, in marketing for the Anesthesia Care segment of Datex-Ohmeda, notes that sensors and cabling can have their connectivity impaired or be easily damaged due to the typically high level of activity in the OR.
Like any other piece of biomedical equipment, there are ways to prolong the usefulness of an anesthesia system. Software upgrades and expansions are one common method, while replacing modular components is another. The typical life span of an anesthesia system is eight to 10 years. Purchasing a system that is flexible and expandable will add years to a systems life, counsels Alt.
Schmaling indicates that anesthesia systems have a recommended depreciation life of seven years. They typically are used beyond that point, but the average turnover time is decreasing and coming in line that seven-year recommendation.
As systems move from simple valves, tubing and standalone boxes to integrated software/processor-based interactive devices, their obsolescence may understandably occur earlier, much like the personal computer industry, she predicts. An anesthesia systems usefulness can be prolonged by purchasing from a supplier with a reputation for providing upgrades and selecting systems with an upgrade path, and with components robust enough to support the upgrades, she adds.
By all accounts, however, the use of the anesthesia system and the pull of healthcare economics determine the systems life expectancy.
The useful working life of a modern anesthesia system can only be determined by the user. This determination is influenced more by the changing clinical practices and healthcare economics than by wear and tear of the device itself, Clark proclaims. Advances in clinical practice, such as minimally invasive surgery, have created a demand for more sophisticated ventilators capable of compensating for the compliance losses due to the decreased patient compliance and increased airway pressures. In addition, the economics of day surgery have led to an increase in spontaneous breathing, resulting in a demand for sophisticated breathing support modes to reduce the work of breathing. Parallel to this, the rapid growth in monitoring and documentation requirements has required multiparameter monitoring and has led to the subsequent integration of monitoring parameters in order to optimally manage the information and data flow.
The useful life of the anesthesia system can be maximized through adherence to the manufacturers maintenance schedules and by the users treating it appropriately, as sophisticated life support equipment, he continues. Manufacturers typically offer upgrades to the anesthesia systems during their time of manufacture. An investment in an upgrade can often extend the useful life significantly.
Logterman proposes that biomeds and engineers take advantage of any training classes offered on the systems purchased by their employers. As anesthesia systems become increasingly sophisticated, techs and engineers will benefit from factory training and access to special tools and procedures, he says.
He also prescribes that hospitals needing to choose a service provider select one who proactively performs and replaces the original equipment manufacturer- (OEM) recommended parts according to the planned maintenance inspections and schedule for all its life support equipment.
Clark offers this guidance.
The most fundamental decision that the biomedical group of any hospital has to make is how they want to support the anesthesia systems. The decision to manage the equipment in-house or to contract this out to the manufacturer needs to be considered based on cost, quality and resources.
Technology is rapidly changing, and keeping up to date with all the changes can result in a heavy training requirement for the biomedical group, he elaborates. Many biomedical groups are realizing that outsourcing much of the life support equipment maintenance is a more cost-effective proposition.
And the constant pressure to cut costs is a reality. Healthcare today is driven as much by financial performance as any other business, reminds Clark.
An anesthesia system is a tool to allow the performance of surgery, which is a revenue-generating activity, he declares. The future of anesthesia technology lies in supporting and improving clinical efficiency in terms of cost, quality and throughput. We can expect to see an increase in the degree of integration of monitoring and information management functions as well as some significant developments in the user interface to further improve the user interaction.