Latest Trends in Diagnosis Therapy

8/13/2019 Latest Trends in Diagnosis Therapy

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Latest Trends in Diagnostics & Therapy

Trends in Medical Diagnostic, Patient Monitoring and Therapy equipment include

portability, connectivity, flexibility and system intelligence. Medical equipment such as digital stethoscopes,

patient monitoring, ECG, EEG, and pulse oximetry have all become more portable through improvements in

battery and battery management technologies, and the proliferation of wireless communications technologies

like Bluetooth and Zig Bee . The addition of features like touch screen control and audio feedback have taken

away the complicated mix of knobs and dials and replaced them with menu-driven displays and user prompts.

On top of this the precision of the sensor signal chain combined with the processing power of todays

embedded processors have paved the way for these instruments to not only notice the smallest perturbation

from normality in a signal, these devices can collect and process trends against large databases and even

suggest a course of action. These improvements in reliability, battery storage capability and usability have also

taken the Automated External Defibrillators (AEDs) from equipment only found in medical facilities and

emergency vehicles to tools deployed in many schools, businesses and other public areas Low power

processing allows an AED to sleep for long time periods, only waking up to run diagnostics, and then quickly

get to full operation when needed. Such as the intelligence to guide the user safely through its use and the

ability to sense if the pads are incorrectly placed on the patient have truly helped drive the proliferation of these

devices. By combining the advances in monitoring capabilities with those seen in motor control, power

management, and control systems, applications such as ventilation/CPAP, dialysis, and infusion pumps have

been made smaller, safer and less expensive. This trend has made it practical for CPAP systems and Infusion

pumps to be placed in the home, and dialysis therapy to move from a hospital-only application to a doctor's

office. Connectivity for portable medical applications has become critical as consumers and caregivers are

requiring data to move from medical devices to data hubs such as computers and mobile phones.


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Patient Monitoring, Diagnostics & Therapy

Medical System Block Diagrams & End-EquipmentSolutions

Find system block diagrams, application notes, tools and software and other related information.

Automated External Defibrillator CPAP Machine Dialysis Machine ECG Electrocardiogram Infusion Pump

Patient Monitoring: OMAP Pulse Oximetry Stethoscope: Digital Ventilator

Advances in battery power management, precision analog, and wireless technologies likeBluetooth and ZigBee are making medical diagnostic, patient monitoring and therapy devices

more portable, connected, flexible and intelligent to minimize cost and improve accuracy foradvanced medical electronics. This trend is helping to bring technologies once found only inhospitals to physician offices and patient homes.

Touchscreen interfaces and audio feedback features have eliminated the need for complexmanual controls, streamlining the user experience. And next-generation embedded processor

performance enables practitioners to detect even the smallest anomalies, aggregate thatinformation across massive databases, and perform complex analyses to determine a diagnosisand suggest a course of therapy.

On this page, you can find system block diagrams, IC product specifications, collateral, design

considerations and tools for your medical device design.
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Patient Monitoring

Integrated multi-parameter portable patient monitoring

with OMAPBlock Diagram

Design Considerations

Over time, multitudes of portable, single parameter monitors/meters emerged for measuring suchthings as blood pressure, glucose levels, pulse, tidal carbon dioxide, and various other biometricvalues. Today, patient monitors are portable, flexible devices capable of being adapted to avariety of clinical applications, supporting various wired and wireless interfaces. Whether themonitor is a single or multi-parameter device; targeted capability, power consumption andsystem versatility are often key requirements. Nowadays, a monitor can move with the patientfrom the operating room to an intensive care unit, to the hospital room, and even into their home.This is paramount in todays world of health care.


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The most important features in todays patient moni tors are mobility, ease of use, and effortless patient data transfer. Mobility includes portability as well as the ability to interface with othermedical devices such as anesthesia machines or defibrillators. Ease of use can be achieved withtouch screen displays and multilevel menu driven profiles that can be configured for theenvironment as well as the patients vital statistics. Data transfer across everything from wireless

to RS232 needs to be possible. Hospitals may support a specific infrastructure throughout allareas; however, ambulance, home and other environments may need support for different protocols. The ever-increasing need to minimize healthcare costs is driving the healthcare providers to move the patient treatment and monitoring outside the hospital. Providing healthcarein highly populated rural and remote areas in emerging economies is driving the need for remote

patient monitoring and telemedicine.

The challenges in implementing such patient treatment and monitoring equipments are strikinglysimilar to cellular phone systems. TIs OMAP technology with embedded ARM and DSP

processor cores directly addresses these challenges. TI has extensive analog front end solutionsfor essential signal conditioning. The OMAP 3 processor performs further digital signal

processing, measurements and analytics to monitor patient condition. Powerful ARM processorruns a high-level OS (HLOS) which makes adding multi-modal monitoring easy and providesextensive user interface and system control. Detecting abnormal conditions and communicatingto a central server is essential in providing timely and on-demand healthcare. OMAP 3 hasextensive peripheral set to support various connectivity options such as Bluetooth, WiFi, Zigbeeand other emerging standards.


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Automated External Defibrillator

Automatic External Defibrillator (AED) solutions from

processors to signal conditioning to power managementBlock Diagram


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Automated External Defibrillator

Overview:Most automated external defibrillators (AED) are highly sophisticated embedded processor-based devices that monitor,ssess and automatically treat patients with life-threatening heart rhythms. They capture ECG signals from thelectrodes, runs an ECG-analysis algorithm to identify shockable rhythms, and advises the operator about whetherefibrillation is necessary. A basic defibrillator contains a high-voltage power supply, storage capacitor, optionalnductor and patient electrodes. It develops an electrical charge in the storage capacitor, creating the potential forurrent flow. The higher the voltage, the more current can potentially flow. The AED outputs audio instructions and

visual prompts. In a typical defibrillation sequence, the AED provides voice prompts to instruct the user to attach theatient electrodes and starts acquiring ECG data. If the AED analyzes the patients ECG and detects a shockablehythm, the capacitor is charged, Where Wc = 1/2CV^2c; and capacitor voltage, Vc(t) = Vc(0)e t/RC, where R =

R(lead)


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CPAP Machine or Continuous PositiveAirway Pressure

Block Diagram


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CPAP or Continuous Positive Airway Pressure is a method of respiratory ventilation used mainly for the treatments ofleep apnea at home. During sleep, the muscles tend to naturally relax causing the upper airway to become narrow. Thiseduces the amount of oxygen in the blood and causes arousal from sleep.

Pressure sensors play an important role for respiration equipment by converting physical values such as airway pressurend flow into a differential signal. The air and flow sensors generate signals to help the microprocessor regulate the

motor to adjust/maintain the desired pressure as the person inhales or exhales. Often, the sensors are very cost-effectivewith large offset and offset drift causing the signals to be off scale, temperature variant and non-linear. Amplifiers withow offset voltage and drift over time and temperature are ideal for signal conditioning.

The actual controlling of the DC Motor can be done by monitoring at least two of the three current phases and the DCus voltage feeding the motor drive bridge. For the phase currents, two approaches can be used: high-side or low-side.

Direct phase measurement or high side, requires high speed difference amplifiers or current shunt monitors and isenerally more accurate. The low-side approach measures near the half bridge ground connection and uses more simplemplifiers which can be less costly but also less precise. The DC Motor is driven by discrete FETs. TI's DRV familyffers an integrated driver and bridge with thermal protection that is smaller, more precise and much more efficient thats highly recommended.

The microprocessor performs multiple operations including sampling the pressure signals and computing a desiredirway pressure and flow level to communicate with the motor. To achieve these operations efficiently and in real-time,high-speed, low-power, highly-integrated microprocessor should be used. A high-quality DSP can be used for suchpplications and will also provide the patient with an ultra quiet operation.


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ECG Electrocardiogram

Block Diagram


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Design Considerations.

TI's new ADS1298 provides eight channels of PGA plus separate 24-bit delta-sigma ADCs, a Wilson center terminal,he augmented Goldberger terminals and their amplifiers, provide for a full, standard 12-lead ECG integrated analogront end. The ADS1298 reduces component count and power consumption by up to 95 percent as compared to discretemplementations, with a power efficiency of 1 mW/channel, while allowing customers to achieve the highest levels ofiagnostic accuracy [view video ]

ECG System Functionality and Evolution

Basic functions of an ECG machine include ECG waveform display, either through LCD screen or printed paper media,nd heart rhythm indication as well as simple user interface through buttons. More features, such as patient recordtorage through convenient media, wireless/wired transfer and 2D/3D display on large LCD screen with touch screenapabilities, are required in more and more ECG products. Multiple levels of diagnostic capabilities are also assistingoctors and people without specific ECG trainings to understand ECG patterns and their indication of a certain heartondition. After the ECG signal is captured and digitized, it will be sent for display and analysis, which involves furtherignal processing.

ignal Acquisition challenges:

Measurement of the ECG signal gets challenging due to the presence of the large DC offset and various interferencesignals. This potential can be up to 300mV for a typical electrode. The interference signals include the 50-/60-Hzinterference from the power supplies, motion artifacts due to patient movement, radio frequency interference fromelectro-surgery equipments, defibrillation pulses, pace maker pulses, other monitoring equipment, etc.

Depending on the end equipment, different accuracies will be needed in an ECG:o Standard monitoring needs frequencies between 0.05-30 Hzo Diagnostic monitoring needs frequencies from 0.05-1000 Hz

Some of the 50Hz/60Hz common mode interference can be cancelled with a high-input-impedance instrumentationamplifier (INA), which removes the AC line noise common to both inputs. To further reject line power noise, the signal isinverted and driven back into the patient through the right leg by an amplifier. Only a few micro amps or less arerequired to achieve significant CMR improvement and stay within the UL544 limit. In addition, 50/60Hz digital notchfilters are used to reduce this interference further.

Analog front end options:

Optimizing the power consumption and the PCB area of the analog front end is critical for portable ECG's. Due totechnological advancements, there are now several front end options:

o Using a low resolution ADC (needs all filters)o Using a high resolution ADC (needs fewer filters)o Using a sigma-delta ADC (needs no filters, no amplifier aside from INA, no DC offset)o Using a sequential Vs simultaneous sampling approach.

When a low resolution (16 bit) ADC is used, the signal needs to be gained up significantly (typically 100x - 200x) toachieve the necessary resolution. When a high resolution (24bit) sigma delta ADC is used, the signal needs a modest gainof 4 - 5x. Hence the second gain stage and the circuitry needed to eliminate the DC offset can be removed. This leads toan overall reduction in area and cost. Also the delta sigma approach preserves the entire frequency content of the signaland gives abundant flexibility for digital post processing.
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With a sequential approach the individual channels creating the leads of an ECG are multiplexed to one ADC. This waythere is a definite skew between adjacent channels. With the simultaneous sampling approach, a dedicated ADC is usedfor each channel and hence there is no skew introduced between channels.

Latest Trends in Diagnosis Therapy

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