Energy Devices & Sutures + Staplers +Pulse Oximetry 💨🧑🏻🎨 Flashcards
(13 cards)
What is hemostasis in Surgery?
Hemostasis in surgery is a process where the surgeon uses various means and techniques or the use devices to control or arrest bleeding during surgery.
How do you classify techniques available for hemostasis during surgery?
It can be broadly classified into:
a) Non- Energy devices
1. ligatures
i. Suture ligatures
ii. Clips
iii. Hemolocks
iv. Vascular clamps (Bulldog clamps)
v. Vascular endo- stapler
vi. Coils/ springs
- Tissue sealant Fibrin Platelet/ Thrombin/ Collagen cross- link/ Gelatin/ coagulation cascade factors)
i. Surgicel
ii. Gel foam
iii. Fibrin glue
iv. Quick clot
v. Alginate - Pressure packing
b) Energy Devices:
- Monopolar
- Bipolar
- Ligasure
- Ultrasonic Energy devices
- Argon Beam Coagulation
- Laser
- Radiofrequency Sealants
Principles of diathermy
Diathermy is where electrical energy is converted to heat energy to produce desirable functions which are cutting and coagulating of tissues.
3 Key principles of diathermy:
- High frequency alternating current
- Heat is generated whenever an electric current is passed through a non- perfect conductor
- amount of heat is proportional to current
Radiofequency: 500kHz to 10 MHz
( 60kHz: household appliances and 100kHZ needed to stimulate muscle and nerve)
** No Neuromuscular stimulation above 100kHz
How does Diathermy works?
3 modes : Cutting , Coagulation and blend modes
a) Cutting ( Pure) Mode
- Continueous waveform output ( unmodulated AC) , sinusoidal
- pure cut ( 100% ON)
- sustained rise in temperature -> cell water instantly vaporized -> cell explodes —> Tissue disruption
b) Coagulation ( Desiccate ) mode
- Use Intermittent waveform output ( modulated AC)
- coagulation ( 6% ON and 94% OFF)
- pulsed output
- less heat produced
- coagulate plasma protein —> desiccate cells
- dead tissue is shrinks —> distortion of blood vessels wall —> coagulating proteins
c) Blend mode
- Combination of cutting and coagulation mode
- Blend ( 50% ON and 50% OFF)
- allow cutting with a degree of haemostasis
d) Fulguration mode
- Very high voltage
- Sprayed over large area
briefly describe the types of diathermy used in surgical practice?
1) Monopolar : high power: 400w
a. The current produced by the generator machine is delivered through an active electrode (handheld) which is then used to cut or coagulate tissues and returns to the generator machine via an inactive electrode (patient plate) which is adhered to the patient
b. The variety of active electrodes that can be used are needle (Colorado pin), lancet, angulated lancet, wire loop, ball diathermy
c. The smaller the tip of the active electrode, the greater the heat produced and vice versa
2) Bipolar : low power= 50w
a. The current produced from the diathermy machine passes between the tips of a pair insulated forceps and returns back to the diathermy machine.
Usually doesn’t require inactive electrode (patient plate/ pad) as the current produced doesn’t travel through the patient but between the tissues within the two tips of the forceps.
b. Safe to be used in patients with pacemakers.
What are the dangers of hazards associated with the use of diathermy during surgery?
1) Patient:
a) Diathermy burns ( as a result of poor contact between the patient plate and patient skin)
- avoid bony prominences, hairy skin and are of previous surgeries/scar tissues
b) patient in contact with other metallic objects
- when any part of the patient’s body is in contact with other metal objects such as stirrups, the electrical circuit will take paths of least resistance and hence that metallic object becomes part of the circuit.
c) Use of monopolar diathermy may pose risk to patients who are on cardiac pacemakers
d) Risk of fire and explosion:
- Alcohol based skin preparations that are used in excess may pool under the surgical towels and can ignited by sparks from active electrode
- Diathermy may ignite intra luminal gas that is present inside a distended bowel
2) To the surgeon and staff
- Electrocution
- Toxic diathermy smoke
- Diathermy burns to surgeon
Complication of electrosurgery in MIS
Direct Coupling: Direct coupling occurs when the surgeon accidentally activates the generator while the active electrode is near another metal instrument
Capacitive coupling :
- Current may be transferred from the active electrode through its intact insulation into adjacent conductive materials typically a metal trocar
- The use of plastic trocar doesn’t entirely eliminate capacitance as conductive tissues such as bowel can also complete the definition of a capacitor ( Capacitance can be reduced)
Insulator failure
What are the other energy devices that are used in surgery?
1) Ligasure:
- Feedback- controlled bipolar that uses current passed between the tips of a pair of insulated forceps
- can seal vessels upto 7mm in size
- Tissues sensing technology in the Ligasure makes use of a computer algorithm to adjust the current and voltage based on real-time measures of tissue impedance
- Has a reduced energy spread profile of <2mm thus potentially decreased risk of injury to adjacent structures
2) Harmonic:
- High frequency ultrasonic transducer
- The active titanium blade vibrates at 55,000 cycles per second
- The resulting mechanical energy causes a breakdown of protein in tissues which creates a coagulum.
- The instrument blade vibrates producing heat pressure changes, leading to low temperature cellular vaporization and rupture that allows for precision cutting.
- Harmonic Scalpel performs at lower temperatures ( 50 -100 degree celcius) , others devices work at high temperatures ( 150 - 400 degrees celcius)
- Can seal vessels up to 5 mm
What is LASER?
- LASER : Light Amplification by the Stimulated Emission of Radiation uses concentrated photons or light energy to cut, coagulate and vaporise tissues. ( convert light energy to heat energy)
- Thermal energy created by LASER produces 3 zones :
- Central zone ( Vaporization)
- Outer zone ( Tissue Necrosis)
- Peripheral zone ( thermal conductivity and repair)
Characteristic of laser:
Collimated: output beam is parallel resulting in minimal energy loss when projected over a long distance
Coherent: waves are all in phase resulting in minimal energy loss
Chromacity: all of the same wavelength, i.e. monochromic
Classification of sutures
Anatomy of suture needle
Types of Surgical Staplers
Pulse Oximetry
Pulse oximetry measures how much oxygen your blood is carrying.
How it works:
1. Light emitter shines two types of light into your skin:
* ➔ Red light (around 660 nm wavelength)
* ➔ Infrared light (around 940 nm wavelength)
2. Oxygenated hemoglobin (HbO₂) and deoxygenated hemoglobin (Hb) absorb light differently:
* ➔ Oxygenated blood absorbs more infrared, less red.
* ➔ Deoxygenated blood absorbs more red, less infrared.
3. A detector on the other side of your skin (usually finger, ear, toe) measures how much light passes through.
4. The device calculates the ratio of red and infrared light absorbed.
5. It then estimates your oxygen saturation (SpO₂) — shown as a percentage.
