Electronic, optoelectronic devices, and nanotechnology

Summary

Introduction

As part of the healthcare team, technicians must ensure medical technology is safe and available when needed by clinicians. In the healthcare workplace, work is done to ensure a device is operating properly. This is in contrast to corrective actions designed to remedy problems as a result of a device malfunction. The kind of work described in this chapter is focused on reducing equipment failures and discovering hidden problems before they could impact patient care or device performance.

Clinical sites and administrators generally define the scope of medical equipment managed by HTM technicians. As discussed in Chapter 2, medical technology is often grouped into three broad categories: therapeutic, monitoring, or diagnostic. Variation among hospitals is common based on historical support or individual skill sets, although devices that are disposable or singleuse and most implantable devices are beyond the responsibility of the HTM technician.

Before any work begins on any medical device, technicians should be sure to utilize appropriate personal safety measures as discussed in Chapter 5.

Device Inspection

When a new device is delivered to an institution, removal from the packing materials, initial assembly, and incoming inspection is performed. The complexity and time required to complete these steps varies greatly depending on the device. As mentioned in Chapter 1, incoming inspections are an essential part of the HTM technician's workload, with efforts focused on the assurance that a new device will function properly when put into service within the healthcare setting.

Preventative maintenance, another important workplace responsibility, evaluates the performance of an existing device to ensure proper operation. These activities are typically scheduled utilizing a predetermined timeline (such as once per year). The goal of these actions is to identify undetected problems before they impact patient care, reducing equipment downtime and reducing overall hospital costs.

Simple visual inspections look for signs of deterioration, damage, or missing hardware. The stressful clinical environment may result in unintended equipment mishandling that can cause broken plastic parts, missing doors or knobs, frayed power cords, or gashes. Power cord damage, especially at the junction with the device, can be both common and potentially hazardous. Experience in healthcare settings will offer technicians the opportunity to see a wide variety of device damage (some surprising and inexplicable), and to develop a special sense to predict and find device deterioration.

Summary

Introduction

The use of technology to push fluids into the circulatory system of a patient has evolved and expanded over time. In the past, glass bottles of fluids utilized gravity to promote fluid flow to “drip” fluids into a patient. As technology expanded into healthcare, the bottles were replaced with plastic bags and gravity was no longer medically adequate. Electromechanical pumps are more reliable and provide constant monitoring of fluid delivery. In addition, the flexibility of some pumps has improved medication dosing and caloric delivery. Healthcare has come to depend on the use of technology to deliver fluids and medications to patients.

Infusion Pumps

One of the most common pieces of equipment in the hospital, the infusion pump (also called intravenous pump, IVAC, and IV pump) delivers medication, blood, or fluid into the patient over a specific period of time at a particular rate. The name used may reflect brand names from the past, including IVAC. Many patients will be connected to several pumps delivering fluids to the patient through a vein (hence, the term “intravenous”). The pump ensures an accurate rate and, therefore, an exact dose. In addition, should there be a problem with the fluid delivery, an occlusion (blockage of the tubing) perhaps, or the complete fluid amount has been delivered, an alarm will sound to alert staff. The electronic monitoring allows delivery of IV fluids with minimum human intervention.

Bags, filled with fluids of many kinds, are hung on poles, connected through tubing to the pump, and then through the pump to the veins of the patient. Settings on the device include delivery/ flow rate as well as alarms to indicate blockages or empty fluid bags.

There are different techniques employed to pump in the fluid. One of the most common is a peristaltic pump. Rollers (in most cases) squeeze the tubing to push in the fluid. Traditional tubing from the fluid- filled bag to the patient is used.

Another method requires some additional disposable cassettes that hold the liquid for a piston to push the liquid. This requires that the infusion tubing be specifically chosen to work with the type of pump the hospital owns.

Summary

A significant reason for death and long-term disability due to head injuries and pathologic conditions is an elevation in the intracranial pressure (ICP) due to vascular compromise and secondary sequelae causing edema. ICP measurements before and after injury in a completely closed-head environment have a significant research value, particularly in the acute postinjury period. With current technology, a tethered fiberoptic probe penetrates the brain and therefore can only remain implanted for relatively short time periods. Use of the probe also can cause complications such as infection and hemorrhage and prohibit immediate (at the time of injury) and long-term measurements of ICP. A small, fully embedded, wireless ICP device may simplify clinical management and research protocols by offering a means for semi-invasive and long-term ICP measurement following brain injury. In this chapter, a new digital wireless ICP (DICP) device is described. The dynamic ICP measurement performances of both the analog ICP (AICP) devices (described in Chapter 2) and the DICP devices are evaluated in a specific traumatic brain injury (TBI) (swine) model of closed-head rotational injury.

Introduction

In Chapter 2, a prototype of an AICP device operating in the industrial-scientific-medical (ISM) band at 2.4 GHz was described that successfully simplified the surgical procedure by reducing the infection rate, the risk of hemorrhage, and the degree of tissue injury.

The AICP device was implanted in a canine model only for a static test, and hypo- and hyperventilation were used to affect variations in ICP. Dynamic ICP variations as a result of TBI in a completely closed-head environment are of paramount importance for understanding the development of a prolonged postconcussion syndrome and facilitating institution of the correct treatment at different stages, particularly in the acute postinjury period. Currently, in experimental (animal) models of TBI, a tethered fiberoptic probe (if inserted before the injury) has to be removed before an injury is induced in order to avoid significant focal damage at the point of probe insertion. Moreover, reinsertion of the probe is possible only after the animal's vital signs have stabilized. However, the act of breaching the cranium after the injury affects the fidelity of the ICP measurements. In addition, proposed noninvasive ICP (NICP) solutions, such as the pulsatility index method based on the use of trancranial Doppler, argued by Figaji et al. [1], have been shown to be insufficient for accurate ICP estimation.

Summary

Introduction

Doppler radar has recently been extensively used in noncontact cardiopulmonary monitoring [1–3]. A continuous wave (CW) microwave signal is transmitted toward a human subject. Physical motion caused by the respiration and heartbeat of the human subject phase modulates the transmitted signal and reflects it back to the transmit antenna, where it is received and phase demodulated to yield the heart and respiration rates of the subject. Physical motion of the human chest during respiration and heart motion are measured to be about 0.2 to 2 and 8 to 20 mm, respectively [4]. Thus the system has to be very sensitive to phase changes, which are caused by path-length variations. For a stationary transmitter and subject, this path length only varies with a subject's heartbeat and respiration. A nonstationary transceiver antenna or a fidgeting subject will produce additional path variations causing interference in radar signal (Figure 7.1).

There are cases where the transmit/receive antenna cannot be assumed to be physically stationary. For example, if the transceiver is a handheld unit used in search and rescue operations or to sense through walls in military applications, “hand shake” of the operator will introduce path-length variations that phase modulate the received signal in addition to that of the target's cardiopulmonary motion. Also, if the antenna is placed on a platform subject to some vibration, the vibration can cause antenna motion, creating an interference with the radar signal. Monitoring a driver in a vehicle is an example of such an application. Thus the final demodulated signal will include components resulting from operator's unwanted hand shake to the extent that life signs monitoring will become impossible due to excessive interference. The fidgeting of the subject, which can be the result of coughing, sneezing, itching, and similar activities, is another source of this type of interference.

While most sources of unwanted interference motion are random, they can still be categorized to a certain extent by their frequency spectrum and amplitude. For example, a 2003 Ford Taurus with a V6 engine being driven on a flat freeway at a speed of 65 mph creates about 3 to 9 mm of shake at a low frequency of 1.2 Hz [5].

The problem of undesired instrument shake is similar in still image and video cameras, where it causes motion blur in the captured image.

Summary

Introduction

One limitation with Doppler radar is that for vital sign monitoring, any torso movement by the subject will affect the measurements. Other limitations include interference from moving objects or people in the vicinity and an inability to detect multiple targets. These issues arise due to the fact that a continuous-wave (CW) radar motion-detecting system is not inherently selective and will detect any motion in its field of view. Various solutions have been proposed for this, such as the use of multiple antennas with blind source separation (BSS) techniques to identify multiple respiration signatures [2,36] and use of two and four radars to cancel body sway [12,38]. BSS techniques are very effective in identifying multiple motion signatures but cannot associate those signatures with a particular source, leading to ambiguity in the interpretation of results. A good solution still does not exist for identification of a subject from the environmental clutter and making the Doppler radar system selective.

Bringing selectivity to the radar implies introducing ways to ensure that the motion signals obtained correspond to the desired source. By rejecting clutter motion and detecting the physiologic motion of a subject, we are implementing the first stage of selectivity. The only way to resolve targets without placing any circuit on them is by spatial resolution and range. Spatial resolution can be brought to the radar through coherent detection using pulse Doppler radar. This principle is used in synthetic aperture radars (SARs) and inverse synthetic aperture radars (ISARs) [33]. In order to achieve good resolution, we would have to use millimeter-wave signals and associated circuitry and would still have ambiguities in the range. Spatial resolution can also be obtained through multiple-input, multiple-output (MIMO) systems and BSS techniques, but the sources of motion would still remain ambiguous. Range can also be calculated using frequency-modulated continuous-wave (FMCW) radars, but then Doppler processing would become more challenging. The resolution provided by FMCW radar is also limited by the bandwidth of frequencies used.

Introducing modulation at the source of motion may allow more flexible solutions compatible with the current Doppler radar system. The way to achieve selectivity would be to have some form of modulated backscatter from the subject and no modulated backscatter from other objects, similar to radiofrequency identification (RFID) systems. Although RFID technology is mature and easily available, it is difficult to apply to motion-sensing applications.

Summary

Introduction

The focus of this chapter is external human respiration. Moving air in and out of the lungs is external respiration and the focus of technological interventions. The exchange of gases in the alveoli is part of external respiration (although it occurs within the lungs) and reflects the effectiveness of breathing – note that internal respiration does not mean “inside the lungs,” it refers to the gas exchange at the cellular level within the tissues. Patients need to move air in and out of the lungs and exchange gases in the alveoli, a substructure of the lungs. Oxygen is taken in by the body and carbon dioxide is expelled. Air is made up of 79% nitrogen, 20.96% oxygen, and 0.04% carbon dioxide. However, the air that is expired out of the lungs contains differing percentages. Expired air still contains 79% nitrogen (unaffected by respiration), but notice that the concentration of oxygen is decreased to 17%, and the concentration of carbon dioxide is substantially increased to 4%.

Respiration Effectiveness

One important patient characteristic that is monitored is the effectiveness of respiration – a patient may be breathing (air moving in and out), but it is more important to know whether this activity is resulting in appropriate oxygenation of the body. One method to examine breathing effectiveness is to evaluate the properties of a patient blood sample. Chemical analysis of blood (often performed at the bedside or in the unit), especially the measurement of pH (i.e. the acidity of the blood), can help clinicians determine a patient's respiratory status. See Chapter 15 for more information regarding blood testing.

Pulse oximetry, as discussed in Chapter 7, is also used to simply and non- invasively characterize the effectiveness of respiration. The percentage of hemoglobin molecules that carry oxygen can be displayed by a simple device and will increase or decrease as the body is able to absorb and circulate oxygen.

Capnography is the measurement of carbon dioxide concentrations in expired air. This technique evaluates the changes in carbon dioxide values over time. Expired air is sampled or passed through sensors that can electronically detect the concentration of carbon dioxide. Sensors that utilize infrared (IR) light and light detectors are typically placed within the tubing that connects patients with respiratory devices.

Summary

Introduction

Interest in ultra-wideband (UWB) technology has increased significantly since the Federal Communications Commission's (FCC's) inquiry in 1998 and approval of its use in 2002. The FCC opened up two bands, the 3.1- to 10.6- and 22- to 29-GHz frequency bands. UWB has been used for both communication and radar applications. The fundamental purpose of this chapter is to open up new areas of application for UWB technologies applied to medicine. This includes pushing the achievable limits in terms of high-accuracy indoor three-dimensional (3D) localization using UWB technology and to use this technology in a real-time location system that tracks multiple tags simultaneously with high 3D accuracy in the millimeter range. The application of this technology goes beyond localization to other areas such as breast cancer detection, human gait analysis, and vital signs monitoring, and the list goes on.

Historically, Time Domain Corporation has pioneered real-time precise location of people and assets. Time Domain is the first company to unleash its full potential [1]. Their pulse-on system enables real-time localization in the most difficult environments – where GPS fails and where ad hoc or moving frames of reference are required. Multispectral Solutions, Inc., also used UWB for multiuser networking applications – more specifically, an ad hoc wireless UWB communications network for tactical voice and high-speed communications, a long-range UWB system for over-the-water and non-line-of-sight voice, data, and video communications, and a wireless UWB communications network for support of both tactical and strategic (long-haul) communications [2].

In this chapter, we will focus on three areas: (1) indoor positioning, (2) human gait analysis and vital signs detection, and (3) early breast cancer detection.

Overview of UWB Technology for Indoor Positioning Systems

It is important to recognize that the use of UWB technology in a high-performance localization system requiring millimeter 3D accuracy has not been well researched, and far fewer systems have been developed compared with its use in cheaper but more widespread systems with lower accuracy requirements on the order of 10- to 15-cm 3D accuracy.

These localization systems based on using UWB narrow pulses are typically comprised of a transmitter and numerous receivers. The transmitter (the tag) has a narrow-pulse generator (in the picosecond range) controlled by a clock, a power amplifier, and a wide-band omnidirectional antenna.

Summary

Introduction

The clinical laboratory is vital to a hospital's ability to treat patients. Bodily fluids from patients are analyzed for their chemical makeup as well as evidence of disease. Many therapeutic and treatment decisions are made based on the results of this important analysis. Almost all testing is automated and most devices perform many tasks. As a very equipment- intensive department, technical support is vital. The high level of complex equipment does require some hospitals to obtain service contracts for the support of clinical laboratory equipment.

Common fluids from patients analyzed include blood, urine, and cerebrospinal fluid. A tremendous number of categories and tests are performed. This chapter focuses on the principles that form the foundation for the complex equipment. Most devices utilize multiple reagents, bar codes, robotics, and computers to perform the sample preparation and multiple tests. In addition to automated fluid analysis, many laboratory tests evaluate tissue and fluid samples for evidence of abnormalities. Many of these tests are not automated and require the expertise of a pathologist or clinical laboratory technician.

The naming conventions associated with this part of healthcare have varied over time. Originally termed medical technology, a shift was made to more clearly identify the profession. Previously, clinical staff who managed sample analysis techniques were known as “med techs,” causing confusion with medical assistants, phlebotomists, and HTM technicians. Now laboratory staff are often called clinical laboratory scientists. Newer labels for the department include medical laboratory, clinical laboratory, and clinical technology.

Clinical laboratories have their own specific regulations, and organizations that offer guidelines and best practices. These include the American Association of Blood Banks (AABB), College of American Pathologists, and Clinical Laboratory Improvement Amendments (CLIA). CLIA observance is a federal requirement.

Blood Analysis

Many tests are performed on blood. A common test is blood cell count. The automation of this test was vital to improvement in analysis speed. W. H. Coulter created an automated method of particle counting using electrical impedance. As the blood cells pass between electrodes, the impedance increases in pulses. These pulses can be counted to determine the amount of cells (particles) in a sample. Since red blood cells and platelets have different sizes, the pulses vary in size. This allows for very specific results.

Summary

Introduction

The technology involved in imaging the inside of the human body is tremendously complex and amazingly broad. There are a vast array of unique devices, but this chapter will deal with general categories of imaging modalities based on the technique or source of image.

Common Imaging Modalities

Ultrasound: this imaging technique uses sound waves to image anatomy and physiology function. Ultrasound can also be used to detect blood flow, anatomic movement (heart valves, for example), and, most commonly, anatomical structures. It is frequently chosen as an imaging modality because it does not use radiation and carries less risk to the patient. Ultrasound imaging uses highfrequency sound waves (1– 20 MHz) which are projected into the body. The waves hit an object, bounce back, and are detected with a piezoelectric crystal sensor (as discussed in Chapters 6 and 9). The distance from the transmitter probe and the anatomical structure can be calculated, and this data is used to produce an image. Computers can manipulate the transducer data to present three- dimensional or moving images.

Transducer probes, which contain both the transmitter and the sensor, come in many shapes and sizes. Some are designed to enter body cavities such as the esophagus or the vagina for better imaging quality. Most commonly, probes are placed on top of the skin and transmit high- frequency waves into the soft tissues. Ultrasound waves are generally blocked by air and bone. This can be a problem since air is contained in the lungs and there are bones surrounding some organs like the brain and heart. However, creative approaches to bypass bones (between the ribs, for example) are utilized to image most organs. In addition, a gel is often used to help block any air between the probe and the skin. This ensures effective transmission of the waves and an unobstructed image. An example of a probe used for a trans- thoracic (cardiac) ultrasound is shown in Figure 14.1.

Because of the inherent safety of this type of imaging, women often undergo ultrasound imaging to evaluate the progress of pregnancy. Many abnormalities can be detected early and, in some cases, perinatal treatment can take place. Another common application of ultrasound is echocardiography. The anatomy and function of the heart can be examined.

Summary

Introduction

Advances in low-power-consumption radiofrequency integrated circuits (RFICs), multifunctional integrated circuits, high-sensitivity sensing electrodes, biocompatible materials, and packaging techniques have made implants with wireless communication functionality and/or wireless charging capability more feasible and practical. However, wireless communication or wireless powering has not been widely used in implants. There are several challenges. The implant applications are typically disease oriented and implementation focused. The designs of implants have to address specific needs in the disease diagnosis or treatment modalities, which are strongly related to both electronic and mechanical parameters. The sensing modalities or therapy methods determine the electrical specifications, while the biological environments often present serious design constrains. The implementation has to suit clinical settings for safe, cost-effective, and relatively easy implantation procedures and, most important, the needs and comfort of patients in daily life.

It is obvious that integration of wireless communication functionality in implants can provide critical and increased capabilities in applications. The outbound communication brings sensor signals and device conditions to the reader outside the body. The sensors can monitor physiologic signals, such as blood pressure, intracranial pressure, core temperature, electrical signals of tissue or motility of organs, and biochemical conditions such as pH and certain protein or factor concentrations, of patients in vivo and in real time. In addition, the wireless communication can periodically report device conditions such as battery level, electrical resistance of electrodes, and current/voltage delivered to tissues. The inbound communication can be used for device reconfiguration, dosage setting, and condition probing. Bidirectional communication will be ideal for remote access of the implants, adding capabilities for real-time feedback as an integrated system between body and computer. The wireless closed-loop system also can provide real-time patient condition alerts, patient self-diagnosis using smart phones, and autonomous treatment-efficacy studies over a population of patients.

From the perspectives of patients, wireless communication removes the discomfort and inconvenience of tethered wires coming out of the body. Currently, the wires either go through small surgical openings in the body, such as for the extension wire from the head in deep brain stimulation, or an orifice, such as the nostril for stomach stimulation and multichannel intraluminal impedance tests or the urethra for bladder monitoring. The tethered wires connecting to the external electronic device, either a reader or a pulse generator, obviously bring some inconvenience to patients and sometimes pain, and they often limit patient mobility, hindering quality of life.

Summary

Introduction

An important responsibility of the HTM profession is related to patient safety. Ensuring the safe use of technology is a vital role of the HTM technician as part of the medical care team. Understanding the human body and its interaction with technology is critical to patient safety.

Healthcare Technology

Many forms of technology are utilized as tools in medical care. The devices must be safe and effective. In addition, the devices must perform in a way that healthcare providers expect, consistently and reliably. Devices range from very simple (without electricity or moving parts) to highly complex (imaging devices). In general, devices fall into three categories: therapeutic, monitoring, or diagnostic.

Summary

Introduction

The beat of the heart and the electrical signal transmitted to create the beat is one of the most familiar waveforms found in healthcare. The waveform deserves this status. The electrical activity of the heart is fairly simple to measure and tells a great deal about the health of the patient. In the very early 1900s, Willem Einthoven invented the electrocardiogram and won the Nobel Prize in medicine for this work.

Patient Monitoring

Monitoring a patient's heart is a very common procedure. A patient's vital signs are often tracked at regular time intervals or continuously (vital signs usually include blood pressure, related to heart function). Using technology means the patient's condition can be tracked without the need for someone standing next to the bedside continually taking measurements. In addition to tracking the condition of a patient continuously, monitoring can provide diagnostic information upon which treatment decisions are based. Vital signs such as blood pressure and respiration are discussed in their respective chapters.

Note about assumptions for vital signs: Most patients in most hospitals are adults (they are simply sicker more often). Therefore, when a vital sign is listed and unlabeled (as to the age/ type of patient) it is assumed to belong to an adult.

Electrical Activity of the Heart

The heart generates electrical signals to contract (pump blood). Cells within the heart have the ability to depolarize and repolarize, and this process generates electrical energy. The electrical signal in the heart begins at the sinoatrial (SA) node, which stimulates the atria (the two upper chambers of the heart) to contract. The signal then travels to the atrioventricular (AV) node, followed by the Bundle of His, and then through the Purkinje network, which stimulates the ventricles (the two lower chambers of the heart) to contract. When the ventricles are being stimulated to contract, the atria are repolarizing.

The electrical signal is called an electrocardiogram. The abbreviation used for this can be EKG (which comes from German Elektrokardiogramm) or ECG (you will find these letters used interchangeably). Some people prefer the term EKG since it is less likely to be confused with the term EEG when spoken. Generally, little consensus exists upon the use of the label EKG or ECG, although the EKG seems to be diminishing in clinical use over time. There may be times when the terms are used together.

Summary

Introduction

Intracranial pressure (ICP) monitoring is a significant tool that aids in the management of neurologic disorders such as hydrocephalus, head trauma, tumors, colloid cysts, and cerebral hematomas. ICP is the pressure exerted on the rigid, bony skull by its constituents, which are brain, cerebrospinal fluid (CSF), and cerebral blood. Increased ICP can lead to brain damage, disability, and death. Various modalities have been developed for monitoring ICP in hospitals and in ambulatory conditions. Currently, only catheter-based systems have made it to clinical practice. The catheter-based systems can only be used in a hospital setting and have a limited useful life owing to drift and the risk of infection. The wired methods of patient monitoring are cumbersome, cause patient discomfort, and can potentially introduce motion artifacts in the measured quantity. The contemporary medical world is witnessing a transition from a wired to a wireless healthcare domain.

Wireless Technology in Medical Use

The application of wireless technology in healthcare is becoming ubiquitous, if it is not already so. The therapeutic and diagnostic applications of radiofrequency (RF) and microwave technologies in medicine have been the subject of extensive study in the past [1–3]. Medical implants for the transfer of information at these nonionizing frequencies have been developed [4]. Research accomplishments using data communication links at microwave frequencies between a medical implant and an external unit have been reported by many researchers. The resonance characteristics of implanted antennas operating at a frequency band of 402 to 405 MHz and their radiation pattern outside the body have been shown to be favorable for short-range medical implants [5]. Poon et al. [6] demonstrated that the optimal frequency for power transmission in biologic media is in the gigahertz range. Gosalia et al. [7] demonstrated a novel approach of establishing a data telemetry link between an implant and an external unit in the 1.45 and 2.45 GHz band for retinal prostheses. Such medical implants are basic components for the success of telemedicine, which refers to the use of telecommunication technologies in healthcare. Telemedicine not only facilitates medical treatment and care but is also gaining popularity in posthospital patient care [8]. It provides expert consultation in remote understaffed locations and advanced emergency care via modern telecommunication techniques [9]. Mobile patient monitoring systems using wireless implants have been developed to maintain records of patient vital signs and history [10,11].

Summary

This chapter will give a status on the current possibilities of analysis at the molecular and cellular levels enabled by the convergence of microwave dielectric spectroscopy and the use of microtechnologies. Highlights of the technique will be addressed, such as its noninvasivity, its specificity in terms of high-frequency signature, its compatibility with high ionic and nutrient contents classically encountered with cell culture media, and its suitability and sufficient sensitivity for cell probing, even down to single-cell investigations. These particularities notably will be performed in the context of cancer studies in order to offer complementary noninvasive analyzing tools to the biologists and physicians for living cells in their typical liquid microenvironment.

Introduction

There are plenty of physical ways to identify and characterize (bio-)matter physically and/or chemically. Whereas humans exploit their traditional senses (sight, hearing, taste, smell, and touch) to probe the environment, (artificial) sensors – especially biosensors, which are the topic of this chapter – also rely on such sensing mechanisms, for example, mechanical (touch) and optical (sight), but also on other types of interactions, for example, electromagnetic. Such techniques feature a key characteristic: the frequency of the electromagnetic waves can be varied over a range (narrow or broad) to get a rich set of data from spectra, and consequently, the technique is called spectroscopy. Combined with the massive progress in micro- and nanotechnology, miniature biosensors based on dielectric spectroscopy have been in use for several decades, first initiated in direct current (dc) and low frequencies (kilohertz and megahertz) and now reaching microwave and millimeter-wave ranges.

This chapter aims at showing the status of the current possibilities of analysis at the molecular and cellular levels enabled by the convergence of microwave dielectric spectroscopy and the use of microtechnologies. To understand the interests of developing microwave-based and miniature biosensors for molecular and cellular investigations, examples of the main and current cellular analyzing techniques that are available in biolabs will be given, followed by an introduction to microwave dielectric spectroscopy. Highlights of such a technique will then be addressed in terms of noninvasivity, specificity, compatibility with the high ionic and nutrient contents classically encountered in cell culture media, and suitability and sufficient sensitivity for cell probing, even down to single-cell investigations.

Summary

Introduction

Many facets of healthcare delivery engage technology as part of patient care, but they do not fit neatly into the traditional categories discussed so far. Some devices are found in specialized areas of the healthcare setting, others found at every bedside. Children use technology (game consoles, for example) in play therapy. Women in labor are monitored using specific equipment. In addition, specialists such as physiotherapists and occupational therapists use many forms of technology. This chapter will explore these various technologies.

Play Therapy

Children's toys have increased in technological complexity over time. The role of play in a patient's recovery is well documented, and technicians support this endeavor. HTM professionals ensure the devices are safe to use in the clinical setting, are secure from theft, can be cleaned appropriately, and are repaired when needed. In addition, some devices need adaptation to suit the needs of a particular patient. Technicians employed in children's hospitals face these challenges utilizing creativity and sensitivity.

Fetal Monitoring

Fetal monitors are utilized to gather information about the fetus and mother, typically tracking uterine contractions and fetal heart rate simultaneously, sometimes printing the information on long strips of paper. The medical team uses the two pieces of information together to evaluate fetal health and labor progress. A fetal monitor is shown in Figure 18.1. Fetal heart monitoring is decribed in more detail in Chapter 7. This monitoring can use indirect measurements or direct, electrical measurements.

Indirect monitoring, called Doppler fetal heart monitoring, uses a transducer placed on the woman's abdomen. The device detects the movement of the fetal heart and converts the motion into sound. Many devices display a fetal heart rate: beats per minute (BPM).

Direct fetal heart monitoring uses an electrode attached to the fetal scalp and a reference electrode on the mother's skin. The measurement technique directly detects the fetal heart electrical activity. This monitoring method requires that the fetus be in a head- down presentation for delivery. In addition, the amniotic membranes which surround the fetus must not be intact.

Monitors used in labor can also measure the strength and duration of contractions. A pressure sensor (strain gauge) is placed externally on the mother's abdomen. The tightening movements of the abdominal muscles with each contraction are detected with the transducer.

Summary

Introduction

Healthcare settings are regulated by a wide variety of groups. Some groups have direct control over operations, such as the state board of health for a hospital. Others offer voluntary guidelines to follow in order to receive insurance payments for patients treated. Some environments have only a few requirements, such as when healthcare is delivered in the home. Understanding the myriad of guidelines, recommendations, and laws is helpful in promoting compliance and supporting safe patient care.

Codes and Standards

The Association for the Advancement of Medical Instrumentation (AAMI) and several other non- profit organizations have developed standards for best practices through consensus within the HTM profession. The standards are not legal requirements but recommendations for compliance. Some examples of AAMI standards are EQ56 Recommended Practice for a Medical Equipment Management Program and EQ89 Guidance for the Use of Medical Equipment Maintenance Strategies and Procedures.

The National Fire Protection Association has established recommendations for healthcare with NFPA 99: Health Care Facilities Code. The National Fire Protection Association first established the code in 1984 “to minimize the hazards of fire, explosion, and electricity in health care facilities providing services to human beings.” Code 99 applies to healthcare and the technology used within many types of clinical settings. The entire code is available online at www.nfpa.org. Some states have adopted NFPA 99 as state law. When states adopt these standards as law, the guidelines become absolute legal requirements.

The NFPA 99 code is revised from time to time. The latest version of the code was released in 2012. References to the 2012 edition code will be made in this chapter.

NFPA 99 Definitions

Anesthetizing locations: An area of the facility designated to be used for the administration of nonflammable inhalation anesthetic agents. (Flammable anesthetics, such as ether, are no longer used in this country. There were many precautions and regulations when flammable anesthetics were used.) Chapter 13 reviews the four types of anesthesia but only when general anesthesia is delivered is the area designated an anesthetizing location by NFPA 99. The other types of anesthesia are not subject to the requirements of anesthetizing locations.

Electronic, optoelectronic devices, and nanotechnology

Refine search

Refine search

Actions for selected content:

Save Search

5077 results in Electronic, optoelectronic devices, and nanotechnology

Summary

Summary

Summary

Summary

Summary

Summary

Summary

Summary

Summary

Summary

Summary

Summary

Summary

Summary

Summary

Summary