Gain Hands On Experience Of Medical Equipment

Published Date: 02 Nov 2017

Table of Contents

Abstract 1

Introduction 1

Electrocardiogram… 5

Introduction, procedures, Analysis, conclusion.. 6

Diathermy and Defibrillation…………………………………………………………………………………………………………………..………4

Diathermy, Types, Experiment and analysis, Conclusion…………………………………..……………………………………..4

Defibrillation, Experiment and analysis, Dangers of defibrillators, Conclusion…………..…………………………….5

Ultrasound Imaging Devices…………………………………………………………………………….………………………………..……………7

Advantages and disadvantages of diagnostic sonoraphy……………………………………………….………………………….2

Devices and discussion…………………………………………………………………………………………………………………..…………2

Vital signs monitor……………………………………………………………………………………………………………………..…………………..2

Devices and discussion…………………………………………………………………………………………………………………………….2

References……………………………………………………………………………………………………….……………………………………………1

Abstract:

In this lab, we had an opportunity to gain hands-on experience of medical equipment. Hence, this lab is different since we did not focus on just one device but in three blocks and each one has at least 2 devices.

Introduction:

Firstly, we started from block one which focused on the area of ultrasound imaging devices such as HITACHI devices (EUB-405 and EUB-525) and Ultrasonix Sonic Tablet and knowing the difference between these devices and the benefits that is introduced in the field of imaging. Secondly, block two which concentrated on Electrocardiograph and performed an experimental test using Welch Allyn CP100 on the simulator to understand the ECG form and why using 12 leads in a practical test with a patient. Also, in this block we know what the important of vital signs monitors is through using such devices like Nellcor N5500 and Welch Allyn spot vital signs LXi which the most important signs are temperature, blood pressure, heart rate and respiratory rate which doctors have to continuous monitoring of the patients, with medical staff being continuously informed of the changes in general condition of a patient. Finally, block 3 focused on diathermy and defibrillation which we used Force EZ Electrosurgical generator and HP Hewlett Packard: codemaster XL plus Defibrillator and knowing the importance of diathermy in surgery through its two modes, cut and coagulation modes and also the importance of defibrillator and how it can save lives.

Electrocardiogram:

Introduction: ECG is a way to diagnose and measure of abnormal rhythms of the heart which actually measures the rate and regularity of heartbeats, the presence of any heart damage and the effects when using such a device to regulate the heart beat like the pacemaker. We did an experiment to perform an EG test using the Welch Allyn CP100 device and its simulator as shown in fig. (1).

Figure 1 CP100 12 leads resting ECG with its simulatorProcedures: -Connect the leads to the simulator and then turn on the ECG and after that also turn on the simulator. â€"Check the lead status, if the lead status screen appears, reattach any leads that are flashing and the ready screen appears. Then, press auto ECG key to perform a normal ECG. â€"Enter the patient data and wait the report to be collected, analysed and printed, then select ‘Exit ‘after printing.C:\Users\Mohamed\Desktop\Pics for lab\2013-03-15 11.02.10.jpg

Analysis: As shown in fig. (2), it shows the output of an ECG as a graph of this device and it can store also that data. Actually, in order to record an ECG waveform in a patient, a differential recording between two points on the body are made at which this difference refers to a lead. As shown in this printing form there are 12 identified leads which they are:http://upload.wikimedia.org/wikipedia/commons/a/a0/ECG_001.jpg

Figure 2 Printing ECG formLimb leads (I, II, III):

Which RA is right arm, LA is left leg, LL left leg and RL is right leg.

Wilson's central terminal VW is produced by connecting the electrodes RA, LA, and LL together, via a simple resistive network, to give an average potential across the body: V_W = \frac{1}{3}(RA+LA+LL)

Augmented Leads(aVL, aVR, aVF) 3- Precordial Leads(V1 to V6)

Conclusion: An ECG is a very important test which can check the problems with the electrical activity of the heart which interprets the heart's electrical activity into line tracings on paper as shown in fig. (9).

Diathermy and Defibrillation:

Diathermy: It is a surgical technique where the heat of electricity is used to cut or coagulate tissues by passing normal electric current through the diathermy machine and converting it into high frequency alternating current (HFAC) which produce enough heat to vaporize or coagulate the tissues. Diathermy units use frequencies from 0.5 MHz to 2MHz. However, diathermy accidents still do occur and a diathermy unit can be potentially lethal if adequate care is not exercised in its use.

Types of Diathermy:

Monopolar diathermy: which is most often used in surgery, including open minimally invasive, colposcopy and hysteroscopy.

Bipolar diathermy: which is a very safe type and usually use forceps.

The effects of diathermy depends on the current intensity and wave form used which there are two modes:

1-Coagulation mode: which produced by interrupted pulses of current (50-100 per seconds), Square wave-form. 2- Cutting mode: which produce by continuous current, Sinus wave-form.C:\Users\Mohamed\Desktop\Pics for lab\analyzer.jpg

Experiment and analysis:

We setup the experiment by using Force EZ Electrosurgical Generator and its analyser which is Metron: QA-ES MKII Electrosurgical Analyser in the piece of meat as shown in fig. (3, 4).

Figure 3 Force EZ Electrosurgical Generator

Figure 4 Metron: QA-ES MKII Electrosurgical AnalyserWe notice that the power is delivered as it is to the specimen that because this generator is provided with the ”instant response technology” which provides surgeons with the advantage of accurately delivering the selected power setting, even through resistant tissue. When a conventional generator is used, both power delivery and cutting efficiency are reduced which means more power is delivered and tissue damage increases. This generator offers two cut modes, both controlled by this technology which provides pure cut for a clean, precise cut and blend for cutting with hemostasis. Also, it offers two primary coagulation modes, low, for low voltage contact coagulation suitable in laparoscopic, high, for efficient noncontact coagulation in most applications.C:\Users\Mohamed\Desktop\Pics for lab\2013-03-15 10.04.06.jpg

Conclusion: Surgical diathermy is an invaluable aid in modem surgery and most contemporary diathermy machines are considered safe. However, diathermy accidents still do occur and a diathermy unit can be potentially lethal if adequate care is not exercised in its use.

Defibrillation: Defibrillation is the definitive treatment for the life-threatening cardiac arrhythmias, ventricular fibrillation and pulseless ventricular tachycardia. Defibrillation consists of delivering a therapeutic dose of electrical energy to the affected heart with a device called a defibrillator. This depolarizes a critical mass of the heart muscle, terminates the arrhythmia, and allows normal sinus rhythm to be re-established by the body's natural pacemaker, in the sinoatrial node of the heart. Defibrillators can be external, transvenous, or implanted, depending on the type of device used or needed. 

Experiment and analysis: We set up the experiment by using the HP Hewlett Packard: codemaster XL plus Defibrillator and DYNATECH-NEVADA Impulse 3000 Defibrillator analyser as shown in fig. (5) and fig. (6).

The procedures is very easy to follow as:https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcSUm8kSkiA5VXCgk8d9V114DHrBPxsSm3WnfQktSRK82AXGznzj

1-Turn on the defibrillator.

2-Turn on the analyser and check that everything is correct and there are not error.

3-Allow the defibrillator to analyse.

Figure5 HP Hewlett Packard: codemaster XL plus Defibrillator4-Deliver this shock to the analyser through the two electrodes as shown in fig. (6).

Finally, check for the accuracy of this defibrillator by checking the value that delivered by electrode to the tester.C:\Users\Mohamed\Desktop\Pics for lab\2013-03-15 10.04.45.jpg

Figure 6 DYNATECH-NEVADA Impulse 3000 Defibrillator analyser-In real test on the patient by also following these simple steps however we held the two paddles in place on the patient's skin while a shock or a series of shocks is delivered. Before the paddle is used, a gel must be applied to the patient's skin, in order to ensure a good connection and to minimize electrical resistance, also called chest impedance (despite the DC discharge).

-A defibrillator is primarily used for two conditions, Ventricular Fibrillation (VF) and Ventricular Tachycardia (VT). VF is when the heart basically twitches and VT is when it beats too fast to actually move blood. A defibrillator will NOT work if there is no electrical rhythm.

Difference between Synchronized cardioversion and Unsynchronized cardioversion:

Synchronized cardioversion  is a LOW ENERGY SHOCK that uses a sensor to deliver electricity that is synchronized with the peak of the QRS complex (the highest point of the R-wave). When the “sync” option is engaged on a defibrillator and the shock button pushed, there will be a delay in the shock. During this delay, the machine reads and synchronizes with the patients ECG rhythm. This occurs so that the shock can be delivered with the peak of the R-wave in the patients QRS complex.

Unsynchronized cardioversion (defibrillation) is a HIGH ENERGY shock which is delivered as soon as the shock button is pushed on a defibrillator. This means that the shock may fall randomly anywhere within the cardiac cycle (QRS complex). Unsynchronized cardioversion (defibrillation) is used when there is no coordinated intrinsic electrical activity in the heart (pulseless VT/VF) or the defibrillator fails to synchronize in an unstable patient.

There are some indications for the use of defibrillator if the patient is apneic, unresponsive, and pulseless and has more than 8 years and 55 pounds. Also there are some contraindications of the defibrillator are: the patient is conscious, breathing, has pulse, less than 8 years old or 55 pounds and also hyperthermia.

Dangers of defibrillators:

We have to make sure that no one including the operator touches any part of the victim (keep a distant) and if there is any water around or under the patient, we have to move him/her to a dry area and cut off wet clothing. It should not be used on a child younger than 8 years old. Also, it will almost never decide to shock an adult victim when the victim is in non-VF.

Conclusion:

Early defibrillation is the single most important factor in determining survival from cardiac arrest. It should be performed with in the first 8 minutes after cardiac arrest. Ideally, the sooner, the better. However, there are risks may be happened when using the defibrillator like skin burns from its paddles are the most common complication of defibrillation.

Ultrasound Imaging Devices

Sonography is suitable and effective for soft tissues imaging of the bodies. It depends mainly on the frequency that used at which some superficial tissues like muscles, breasts, tests and -some glands like parathyroid glands are imaged at higher frequency (7-18 MHz) that provides better lateral and axial resolution. However there are some deeper structure like kidney and liver are imaged at lower frequency (1-6 MHz) but with lower lateral and axial resolution however greater penetration. Axial resolution, also known as longitudinal resolution is resolution in the direction parallel to the ultrasound beam which is not affected by the depth of imaging. Axial resolution = (cycles in the pulse x wavelength)/2. Lateral resolution is the ability of the device to distinguish 2 points in the direction perpendicular to the direction of ultrasound beam which is affected by the beam width and the depth of imaging as shown in fig. (7).http://echocardiographer.org/Echo%20Physics/Axial-and-Lateral-Resolution.jpg

Advantages and disadvantages of Diagnostic sonography:

Figure 7 Axial and Lateral resolutionsIt is cheap in compare with X-ray or CT and it has not long-term side effects which is comfort for the patients. It is also able to image soft tissues and bone surfaces in an efficient way which offering live images and showing the organ structures. It is easily carried as it is small. In higher frequencies, it offers better spatial resolution than in other imaging modalities.

However, its devices have problems for penetrating bones. Due to the difference in acoustic impedance between the transducer and organ, it performs very badly since there is air between them. Also, there are some problems when imaging fatty patients. It needs an operator with high level of skill and experiences and make an accurate diagnosis. There is no scout image.Hitachi EUB-525 F Ultrasound System

There are several modes for ultrasound which are used in medical imaging: A-mode (amplitude mode), B-mode (brightness mode), C-mode. M-mode (motion mode), Doppler mode, Pulse inversion mode and Harmonic mode.

Devices and discussion:

Figure 8 Hitachi EUB-525-As shown in fig. (8), HITACHI EUB-525 is a full featured mid-size system capable of B-mode, M-mode, Doppler, Colour Flow and Colour Angiography which has an intelligent key system that provides user-friendly intuitive operation and Toggle keys for application specific functions.http://www.absolutemed.com/core/media/media.nl?id=10801&c=717228&h=5b23d898d2ebdeadb928

-As shown in fig. (9), HITACHI EUB-405 is a small portable unit weighing less than thirty pounds and compatible for wide range of transducers like dual and triple frequency transducers. It is capable of B-mode and M-mode with split screen. For the HITACHI devices, there are several different imaging probes are used like linear, convex, 4D, biopsy, laparoscopic, cardiovascular, echo endoscope and endocavity.

Figure 9 Hitachi EUB-405

Figure 10 Ultrasonix sonic tablet-As shown in fig. (10), Ultrasonix Sonic Tablet is a compact ultrasound system with a 19” touch screen that can be mounted from the ceiling or wall to preserve floor space. It is ideal for guiding minimally-invasive procedures which can connect 2 transducers for abdominal and pelvic procedures. SonixTablet is a flexible system that is being used for various applications and settings including biopsy guidance in interventional suites and fine needle aspiration.C:\Users\Mohamed\Desktop\Pics for lab\2013-03-15 10.47.10.jpg

The difference between the three machines, especially about frequency and functions is depending mainly on the transducers used. Time Gain Compensation, TGC, is used for all three machines which allows for stepwise increase in gain to compensate for greater attenuation of ultrasound waves returning from deeper structures.

Vital Signs Monitoring

Monitoring of vital parameters most commonly include at least heart rate, blood pressure, also pulse oximetry and respiratory rate. Multimodal monitors with more vital parameters are now commonly integrated in the bedside monitors, for example, in ICUs. The vital signs monitors are the ideal solution for taking routine patient vital signs or monitoring before, during and after procedures, minor surgery and treatments.

Temperature: It is commonly considered to be a vital sign most notably in a hospital setting which this recording gives an indication for the body core temperature which is normally tightly controlled.

Blood pressure: It is recorded as two readings; a high systolic pressure, is the maximal contraction of the heart, and the lower diastolic. A normal blood pressure would be 120 being the systolic over 80, the diastolic. The difference between these pressures is called the pulse pressure.

Pulse rate or heart rate: It is usually measured at the wrist or the ankle and recorded as beats/min. which is the physical expansion of the artery. It is also measured by listening directly to the heartbeats using a stethoscope. It varies with age which is 50-80 beats/min. for adults anywhere.

Respiratory rate: It varies with age, but the normal reference range for an adult is 12â€"20 breaths/minute. It also involves the measurements of the saturated percentages of oxygen in the blood referred to SpO2 which is measured by an infrared finger cuff.

Not only those four vital signs are monitored but also there are more vital signs monitoring like cardiac monitor, hemodynamic monitor, neurological monitor, blood glucose monitor and so on.

Devices and discussion:C:\Users\Mohamed\Desktop\Pics for lab\Elance.jpg

Figure 11 élance elite Vital Signs Monitor- As shown in fig.(11), the élance elite Vital Signs Monitors which offer high-performance monitoring of essential parameters which monitor ECG (3- and 5-lead), respiration, non-invasive blood pressure, peripheral O2 saturation and two temperatures. Also, they are intuitive and easy to use â€" their touchscreen user interface with a single level menu provides quick, simplified operation. They are available with two sizes of ultra-bright wide colour displays (10.2” or 12.1”), for clear visualization of up to five waveforms and up to seven numeric displays. All models provide 120 hours of trends. http://www.medivent.gr/products/1240322766_C%20MN%20N5600.jpg

Figure 12 Nellcor N5500-As shown in fig. (12), the Nellcor N5500 which combines the five most common vital signs measurements in one monitor which are non-invasive blood pressure, SpO2,respiratory rate, temperature and ECG which is easily connected to station or printer. Although compact the N5500 incorporates a 6.4inch colour TFT LCD screen, clearly laid out so that it can be easily and quickly read. Colour coded buttons and control knob make the N5500 easy to use, you can spend less time configuring the monitor and more time caring for your patients. Rechargeable battery and roll stand, as well as an integrated top handle to ensure continuous monitoring during transport.http://www.welchallyn.com/images/products/previewsize/Multiparameter%20Spot%20Check%20Devices/Vital%20Signs%20Devices/spotLXibrnnlcr_45NE0E1_product_MC.jpg

Figure 13 Welch Allyn, spot vital signs LXi-As shown in fig. (13), Spot Vital Signs® LXi which combines the most common vital signs measurements in one monitor, non-invasive blood pressure, SpO2,pulse rate and temperature which is easy to use, fast , accurate and flexible. It can measure the blood pressure in 15 seconds as the cuff is inflating which save time and comfort for the patient. It also provides the error messages with description and real solutions not just error codes.