In the era of advanced science, electrosurgical diathermy (ESD) machine is one of the essential devices in medical science. The techniques of electrosurgery used today were developed in the early part of the 20th century, although the history of the technique goes as far back as the early 19th century, when the French physicist Becquerel first demonstrated electrocautery using electricity to use to heat a wire. needle. Monopolar electrosurgery is the radiation of the HFAC from the diathermy via an active electrode through the patient's body tissues and then returned to the diathermy machine via a Return electrode (patient feedback block).
Bipolar electrosurgery is the emission of the HFAC from the diathermy machine with one prong of a bipolar forceps through the tissue placed between the forceps tips and returned to the diathermy machine via the second forceps.
METHODOLOGY OF THE DESIGN
CHAPTER-2
Introduction
Electrosurgical diathermy machine
- THEORY OF ELECTRICITY
- THE EFFECT OF ELECTRICITY ON TISSUE
- CONCEPT OF ELECTRO SURGICAL DIATHERMY
- PRINCIPLES OF ELECTROSURGERY
- THE ELECTROLYTIC EFFECT
- THE FARADIC EFFECT
- THE THERMAL EFFECT
- USE OF THE THERMAL EFFECT IN ELECTRO SURGERY
- THE HEATING EFFECT
- The current density (current divided by area)
- The conductivity of the tissue
- Use of electrode cutting needle of electrosurgical diathermy machine
The conductivity of a specific tissue type is the conductivity of the tissue sample in the conductivity cell multiplied by the length of the conductivity cell and divided by the cross-sectional area of the conductivity cell. Monopolar electrosurgery is the emission of HFAC from diathermy via an active electrode through the patient's body tissues and then returned back to the diathermy apparatus via a dispersive electrode (patient return pad). However, when an alternating current is used, the direction of movement of the ions changes with the frequency of the current.
The tissue is heated with an electric current, whereby the heating depends on the specific resistance of the tissue and on the density of the current and the duration of the application.
THE SHAPE OF THE CUT ELECTRODE USED
The Speed at Which the Incision Electrode Is Used To Cut Through the Tissue
Electrode Is Used To Cut Through The Tissue
THE INTENSITY OF THE HF CURRENT OR HF POWER
If the intensity P>Pf is too high, sparks are created between the incision electrode and the tissue, which, due to the high temperature, coagulates the incision surface to the focal point.
THE CHARACTERISTIC OF THE HF CURRENT WAVEFORM
The essential characteristic of the mixed shear waveform is that it is pulse modulated RF current. For some surgical procedures the surgeon wants a clean cut, for others a cut with more or less coagulation.
A pure cut is obtained by
A deeper coagulation is obtained by
HF (HIGH FREQUENCY) SURGICAL TECHNIQUES
- MONOPOLAR ELECTROSURGERY
Monopolar electrodes are available in an assortment of tips
BIPOLAR ELECTROSURGERY
Unlike monopolar electrosurgery where the patient's body forms a large part of the electrical circuit, with bipolar electrosurgery only the tissue grasped between the tips of bipolar forceps forms part of the electrical circuit. These bipolar forceps contain two active electrodes, which also return the current, the same as a patient plate electrode in monopolar electrosurgery. Both electrodes are isolated from earth and are led directly to the site of surgery.
When using bipolar electrosurgery, the active electrodes that deliver power to the surgical site can be activated either by hand or foot.
The advantages of bipolar electro surgery are as follows
The disadvantages of bipolar electro surgery are as follows
- ELECTRO SURGERY MODES
- CUTTING (PURE & SPECIALIST)
- BLEND
- COAGULATION MODES
- RISKS AND SAFETY DURING HF SURGERY
- Endogenous burns
- Pseudo burns
- ACCIDENTAL BURNS DUE TO INATTENTIVENESS
Warning: During electrosurgery there are always sparks between the active electrode and the patient's tissue. Warning: Alcohol solutions usually burn as invisible flames, which can cause burns to the patient. Endogenous burns can be excluded if the patient has not had contact with electrically conductive parts in the area where the necrosis is found.
Ultimately, this "burn" was found to be necrosis caused by insurance to the patient's tissue from the operating table. If the neutral electrode is not used correctly or not at all, there is a very high risk of burns at the point of application of the neutral electrode and at other points on the patient's body. The user is therefore advised to check for proper contact between neutral electrode and the patient.
Warning: The effective contact area of the neutral electrode with the patient's skin during HF surgery must be sufficient for the HF output used. If gel patient plates are used, it is of utmost importance that the gel is applied evenly over the entire conductive area of the patient plate. Warning: Damaged electrodes, electrode cables, connectors, and other defective accessories can cause serious burns to the patient.
Accidental activation of the device may result in burns to the patient if the active electrode touches the patient directly or indirectly through electrically conductive objects or wet clothing. Warning: Accidental activation of the RF generator can cause serious harm to the patient if the electrode comes into direct or indirect contact with the patient.
CHAPTER-3
DESIGN CRITERIA OF ELECTRO SURGICAL DIATHERMY
FUNCTIONAL BLOCK DIAGRAM OF ELECTRO SURGICAL DIATHERMY MACHINE
Electrosurgical diathermy consists of
DESCRIPTION OF THE COMPONENTS .1 20KHZ OSCILLATION CIRCUIT
In the time delay mode, the time is precisely controlled by one external resistor and capacitor. For stable operation as an oscillator, the free-running frequency and the duty cycle are both accurately controlled with two external resistors and one capacitor. The circuit can be activated and reset on falling waveforms, and the output structure can source or sink up to 200mA.
3.2.2 500 KHZ OSCILLATION CIRCUIT
- PULSE DURATION MODULATION CIRCUIT
- CONTROL AND SAFTY CIRCUIT WITH AUDIO TONE GENERATOR AND MODES SELECTOR
- HF ALTERNATING CURRENTPOWER OUTPUT CIRCUIT
- MOSFET DRIVERS
- ISOLATED PATIENT CIRCUIT
- CIRCUIT PROTECTION AND SNUBBERS
- DC POWER SUPPLY CIRCUIT
- TRANSFORMER DESIGN
We can adjust ON or OFF time of the oscillation using the variable resistor RV1. The term duty cycle describes the ratio of 'on' time to the regular interval or 'period'; a low duty cycle corresponds to low power because the power is off for most of the time. The main part of the HF AC output circuit is made of dual power MOSFET Q1.
When using N-channel MOSFETs to switch a DC voltage across a load, the drain terminals of the high-side MOSFETs are often connected to the highest voltage in the system. C1 converts the full-wave ripple output of full-wave bridge rectifiers BR1. C1 converts the full-wave ripple output of the rectifier to a smooth DC output voltage.
The C4 converts the full-wave ripple output of the full-wave bridge rectifier BR2. The C4 converts the full-wave ripple output of the rectifier into a smooth DC output voltage. The C4 converts the full-wave rippled output of the rectifier to a smooth DC output voltage.
C7 and C8 convert the full-wave ripple output of the rectifier to a smooth dc output voltage. The number of turns varies inversely as the size of the core, while the weight and bulk of the transformer is proportional to the power handling capability of a transformer.
Efficiency and Regulation
Volt-amperes versus Watts
The primary of a transformer behaves like an inductor with a resistance and the current drawn by it is out of phase with the voltage. There is a tendency among transformer designers to use the terms 'watt' and 'volt-ampere' interchangeably, but the distinction between the two terms should be kept in mind when dealing with light reactive loads, because the actual power consumption is equal to ExIcosΦ and Φ may vary with load.
Core Area
The constant C has something to do with the ratio of the weight of iron to the weight of copper, and must be changed according to the application. The gross core area is more than the actual area due to the thickness of insulation between dies. To know the value of core area, the value of gross core area can be calculated by considering the stacking factor.
Basic Transformer Equations
Transformer Calculations
If you prefer square centimeters, you can use the adjusted formula.
RISKS AND SAFETY FOR DESIGN OF ESD
This article will review the potential dangers associated with this, how they occur and how they can be prevented.
Electrical supply
How does electricity damage the body?
Current
Current pathway and density
Type of current
Current duration
Burns
How might electricity flow through the body?
Resistive coupling
Capacitive coupling
How can we prevent electrocution?
General measures
Equipment design
This should prevent any chance of the accessible part becoming live, so no ground wire is necessary. However, the risk of microshock remains and the latest medical electrical equipment standards do not recognize Class III, as voltage limitation alone is not sufficient to ensure patient safety.
Type designation
Type B
Type BF
Type CF
Equipotentiality
All accessible conductive parts of Class II equipment are protected from the power supply by double or reinforced insulation.
Isolated (floating) circuits
Circuit breakers
PCB Design
In Bangladesh there is no such company or industry designing double layer PCB.
Construction of Electro Surgical Diathermy
Major component of Electro Surgical Diathermy PCB
Here, the fitting of the electrosurgical diathermy box with component charge PCB and the complete connection are shown in the picture.
Electro Surgical Diathermy Accessories
LIST OF COMPONENTS WITH PRICE
COMPARISON OF ADVANTAGES PROVIDED BY THE DESIGNED ESD MACHINE
CHAPTER -4
Operation of Electro Surgical Diathermy
- TECHNICAL SPECIFICATION OF ESD
- NAME AND FUNCTION OF THE OPERATIONAL PANEL
- HOW CAN OPERATED THE EQUIPMENT Mode-1
- Auto (Monopolar Cut & Monopolar Coag), Monopolar Bland, Monopolar Micro mode
Function Select Button: This button is to select the type of monopolar and bipolar mode. The unit is equipped with a return electrode safety system (RESSY) that monitors the electrical connection between the neutral electrode and the equipment. If any loss of continuity occurs, an LED will illuminate and an audible alarm will sound to inform the user of the above condition and power output.
Monopolar output connection: This output connection is only used to connect the three-pole handpiece. Bipolar output terminal: This output terminal is only used to connect the bipolar tweezers. Buzhear adjustment knob or volume control: A volume control is included to adjust the Buzhear volume.
Turn off the power switch, intensity control knob is set low and connect to the power box after observing the regular voltage and proper earthing. Contact the three-pin handpiece plug to the three-pin handpiece output socket. Then turn the power switch ON, press the pedal and turn the set output intensity regulator clockwise and select the desired output power/intensity.
Mode-2 Bi-polar coagulation mode
MAINTENANCE AND CARE a) Preventing damage to the unit
Remove plugs and plug unit accessories by gradually pulling on the plug shaft rather than pulling hard on the cable.
Cleaning, disinfecting and sterilization of the accessories
Monopolar and bipolar electrodes Cleaning
Patient plates with cables, plugs and rubber straps.Patient plates with cables, plugs and rubber straps should be cleaned disinfected, before and after use
CHAPTER-5
DISCUSSION
So the design of our ESD is efficient and cost-effective compared to ESDs of developed countries. Most hospitals and clinics use Indian and Chinese electrosurgical diathermy, which involves a lot of foreign currency. With the production of electrosurgical diathermy, we can save foreign exchange, expand the labor market with a qualified workforce.
To ensure adequate safety requirements, ESD is designed according to British Standard 5724 for the safety of medical equipment, which was revised in 1989 by IEC 601. This induces a current in the third winding causing the relay to break the circuit to reduce the possibility of a serious problem. electric shock.
CONCLUSIONS
RECOMMENDATIONS
