The Diathermy And Defibrillation Biology Essay

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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, there should be enough knowledge and experience to use the diathermy to avoid accidents.

2.1.1. 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.

2.1.2. 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).C:\Users\Mohamed\Desktop\Pics for lab\analyzer.jpg

Figure 4 Metron: QA-ES MKII Electrosurgical Analyser

Figure 3 Force EZ Electrosurgical GeneratorWe notice that the power is delivered as it is to the specimen that because this generator is provided with the "instant response technology" which has the advantage of delivering the selected power by high accuracy in contrast to use the conventional ones which reduce the power and hence the efficiency of the cut. Therefore, it needs more power to deliver which leads to tissue damage. 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 coagulation processes which need low voltage contact high, for efficient noncontact coagulation in most applications.C:\Users\Mohamed\Desktop\Pics for lab\2013-03-15 10.04.06.jpg

2.1.3. Results

When we applied the Force EZ Electrosurgical Generator on the specimen of meat and check the results on the analyser we found that for the power=45W, the analyser detected it as 45W and current=450mA and voltage=400v when using the cut mode, however for the coagulation mode it delivered as 40W, current=420mA and voltage=600v and the solution is not obvious.

2.1.4. Conclusion

Surgical diathermy is an invaluable aid in modem surgery which help surgeons to cut tissues by high accuracy of delivering the power they need and also to coagulate if the need. Most of diathermy are safe and need more knowledge to deal with in order not make any damage and avoid accidents.

2.2. Defibrillation

Defibrillation: it is a process that applies an electric shock to the heart in order to depolarize the inner electrical conduction system of the heart. Therefore, it save the patient's live by re-establishing the normal contraction rhythms in his heart which may be have VF' ventricular fibrillation' or arrhythmia. It can deliver its shock through using a device which called defibrillator.

2.2.1. Experimental procedures

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 are very easy to follow as:

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 body for delivering the shock since the shock is delivered only when the control circuits sense the next R wave. Before the paddle is used, a gel must be applied to the patient's skin to make sure that there is better connection and also to low the electrical resistance.

-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. Since it is not working if there is no electrical rhythm.

Difference between Synchronized cardioversion and unsynchronized defibrillation:

Synchronized cardioversion "low energy shock": it uses a sensor in order to synchronise with the highest point in R wave which through pushing the shock button, there may be delay in the order of ms that occurs to give the time to the shock to be delivered with R wave in the patient.

Unsynchronized defibrillation "high energy shock": once pushing the shock button, this shock is delivered immediately to the patient since it may be fallen in any part of QRS complex which it is using in the case of VT or VF or when the defibrillator could not able to synchronise with the patient.

2.2.2. 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.

2.2.3. Results and discussion

When we used HP Hewlett Packard: codemaster XL plus Defibrillator with an input = 20 joules for the synchronised mode, the DYNATECH-NEVADA Impulse 3000 Defibrillator analyser delivered it as 21 joules and the delay time was 21 ms since the average of the best value of the delay time is

(20-30) ms.

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. Hence, 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.

2.2.4. 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.

3. Ultrasound Imaging Devices

3.1. Introduction

Figure 7 Axial and Lateral resolutionsSonography 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). The elastography function will used to measure the softness of the scanned tissue which will lead to better diagnosis.

-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.

Colour Doppler: It is used to represent the flow direction of the blood using blue and red colours and calculated through the equation:

Since is the normal frequency [Hz], v is the velocity of blood cells [], c is the speed of sound [1450].

3.1.1. Advantages and disadvantages of Diagnostic sonography

It 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

3.2. 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.

Figure 9 Hitachi EUB-405-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 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

3.3. Results and discussion

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. However, dynamic range is used for enhancing the image contrast. The Hitachi EUB-525 has an average axial resolution of 0.85 mm by using a linear array with 7.5 MHz. It would measure the smallest axial distance of two dots. The axial resolution of the ULTRASONIX SonixTablet has an average deviation of 0.65 mm by using a linear array of 10 MHz The normal axial resolution of the Phantom, smallest distance between two dots, amounts 0.5 mm. Consequently could be proved that the axial resolution of the Hitachi EUB-525 ultrasound device has an error which a deviation of 0.35 mm per measured distance. The ULTRASONIX has an average error of 0.65 mm per measured distance.

4. 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.

4.1. Important vital parameters

Temperature: It is very important one, vital sign, 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, maximal contraction of the heart, and the lower diastolic. A normal blood pressure would be 120 / 80. The difference between these pressures is called the pulse pressure which 120 refers to the systolic pressure and 80 refers to the diastolic one.

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, which its range for adults is from 12 to 20 breaths per 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.

SpO2 is calculated through the equation: since T is the transmission coefficient, A0 the input of the ray and A1 the output of the ray:

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.

4.2. Devices and discussionC:\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 BP, and 2 temperatures. It has a touch screen with colour display for better visualization which is simple to use its simple operations.

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.

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.

4.3. Results

When we measured those vital signs, they were almost the same for the above three devices since they are very simple to use and measure.

5. Conclusion

In this report, one could able to differentiate of most of medical devices used nowadays for monitoring, for imaging of soft tissues using ultrasound and for surgery of using diathermy and defibrillator throughout knowing the principles of each device. So, one had now an opportunity to gain hands-on experience of medical equipment. One could understand the importance of the ECG for checking the problems of the heart which interprets the heart's electrical activity Also, it easy now to use a defibrillator in order to save a patient life whatever he needs it in the train stations or anywhere, besides also one could understand the principle of the diathermy and how to use it.

Knowing also the using of vital signs monitors is very important to check the vital parameters that may be used it at home or at office like the blood pressure and the temperature since nowadays it is very easy to use the devices of these vital parameters. The devices that use in ultrasound imaging ease the process nowadays to surgeons or doctors to image soft tissues of their patient like muscles, breasts, tests and also glands and it can be used for deeper structures like kidney as well by high resolution and accuracy.