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What is the fire triangle? What are its components?
- Demonstrates that no one person alone is responsible for fire prevention. Fire prevention requires intraoperative collaboration with at least one of the other two professions.
- • The surgeon yields the ignition source.
- • Anesthesia controls the oxidizers (oxygen and nitrous).
- • RN personnel are frequently in control of the safe use of potential fuels (alcohol prepping solutions and sponges).
What is an oxidizer?
- An oxidizer is a substance that will support the combustion of fuel.
- Most fuels burn only in the gaseous state and ignite only when sufficient vapors mix with oxygen.
- Heat produces these vapors by evaporating liquids or vaporizing solids.
- Although oxygen from the air combines with the fuels during surgery during a fire, the OR has other sources of oxygen
O2 is heavier than air, why is this important?
- It will collect in low-lying cavities/areas: open chest cavity or under the drapes.
- Drape fabrics will absorb oxygen and retain it for some time.
TRUE or FALSE. Oxygen-enriched environment will also allow some materials (ie. plastic) to burn that would otherwise not normally burn at RA.
How does N2O provide oxygen and help combustion?
- Oxygen for a fire can also be supplied from thermal decomposition of N2O. Heat from sources found in OR or fire will liberate oxygen from nitrous, allowing it to support combustion.
- Within the context of surgical fires, any mixture of oxygen and nitrous is considered to be an oxygen-enriched environment.
- In the event of a fire, the supply of nitrous as well as oxygen must be shut off quickly.
OR supplies that support combustion:
- O2 catheters
- surgical drapes
- alcohol cleansing solution
- petroleum-based ointments (lacrilube)
What is fuel?
Fuel is anything that can burn – Including almost anything that comes in contact with patients as well as the patients themselves.
Some more commonly found fuels in surgery include...
- GI tract gases (methane, hydrogen, hydrogen sulfide)
- drapes, gowns, & sponges
- breathing circuits
CDC recommends alcohol-based gel solutions for hand hygiene and alcohol-based chlorhexidine solutions for skin preps. Now they say the patient cannot be draped for _____minutes
- 3mis – RNs should also ensure that there is no pooling of solution.
- Potential for fire is augmented when the alcohol-based antiseptic is applied in ways that allows pooling (may not even see it because it under the patient).
- Sponges themselves will help to prevent that.
- Providone-iodine solutions are also flammable. Similar cautions must be made during prepping.
Under the right conditions, some surgical ointments can burn. Describe how petroleum-based ointments can potentially ignite.
- Some petroleum-based ointments used in oxygen-enriched environments will ignite when enough heat is present to cause vaporization.
- These materials must vaporize and mix with oxygen to allow ignition.
- Globs will not easily ignite because its mass absorbs considerable heat before vaporization occurs.
- However, thin layers have low mass per area and need less heat to cause vaporization, and are easier to ignite.
Will water-based ointments burn as easily as petroleum based?
- Water-based ointments (surgilube) will not burn easily.
- Head and neck surgery – may put surgilube in the patient’s hair.
What is an ignition source?
Heat input from a variety of sources increases the oxidation rate of fuel, oxygen mixture until combustion will occur.
what are some sources of heat in the OR that could be an ignition source?
- Overhead surgical lights
- cautery units
- heated probes
- drills & burrs
- fiberoptic light sources & the cables
- These sources produce temperatures from several hundred to a few thousand degrees Fahrenheit. (Enough to ignite most fuels.
- Incandescent sparks produced by electric cautery or high-speed drills and burrs can cause fires.
- Lasers can case sparks when energy hits an instrument or the laser fiber itself may be damaged.
- Even glowing embers of charred tissue can provide enough initial heat to ignite some fuels – especially when you are using oxygen around it.
TRUE or FALSE. A few seconds after deactivation, a heated cautery probe tip, a fiber optic cable tip, or a laser contact tip won't retain enough heat to melt plastics or ignite fuels.
FALSE! it can contain enough heat
What is different regarding lasers compared to to other heat sources
- While these devices (heated cautery probe tip or a fiber optic cable tip) must be in contact with the material to heat it, a laser can heat from a few centimeters to several meters away.
- A fiber optic light source may take a minute or so to heat a drape to the point of combustion, while a laser can cause this almost instantaneously
Ohm's law for electricity
(Instead of BP = CO x SVR)
E=I x R
- E= electromotive forces (volts)
- I= current (amperes)
- R= resistance (ohms)
In order for electricity to occur electrons must move ______________________.
A potential difference needs to exist between these two points, what is this expressed in?
- from an area of high concentrations to low area of concentration.
- Expressed in volts
What is direct current? Name some devices that use DC
- Direct flow of electrons in the same direction.
- Flashlight battery, laryngoscopes, twitch monitors)
What is alternating current?
- Alternating flow of electrons occurs in 1 direction then reverses itself at regular intervals. (Electrical Power Company)
- In OR, most current is AC.
In the US, utility companies supply electrical energy in the form of ACs of ___volts at a frequency of ___Hz.
120volts at a frequency of 60Hz.
TRUE or FALSE. Either AC or DC can be pulsed or continuous in nature.
Ohm’s law is accurate when applied to _____
- But with AC circuits, the situation is more complex because the flow of the current is opposed by more complicated form of resistance called impedance.
- Impedance: the sum of the forces that oppose electron movement in the AC circuit.
- It consists of resistance (Ohm’s) but also takes capacitance and inductance into account
What is a hertz? What is it in the USA?
- Frequency in cycles per second at which the AC current reverses direction ( # of times the AC reverses itself in 1 second).
- 60 hertz in USA.
- As frequency increases, impedance to flow decreases and more current is allowed to pass
What is a volt?
The SI unit of electromotive force, the difference of potential that would carry one ampere of current against one ohm resistance
What is an ampere?
flow of electrons/sec past a given point. When this happens, heat & light are produced
What is resistance?
- Resistance includes forces that oppose current flow or is an impendence to flow.
- Higher resistance, less amount of current will flow
- If short circuit, there will be 0 impedance.
complete circuit is closed loop in which voltage source (electric company) drives the current through an impedance and the current is return eventually to original source Potential differences exist between hot and neutral wires.
Whereas electrical power is _________in the home, it is usually ___________in the OR.
- UNGROUNDED IN OR!
In the home, electrical equipment may be _________but it should ALWAYS be _______ in the OR
- grounded or ungrounded
- Grounded equipment in OR!
- In a grounded power system (like a home), it is possible to have either grounded or ungrounded equipment, depending on when the wiring was installed and whether the electrical device is equipped with a three prong plus containing a ground wire.
TRUE or FALSE. To provide an extra measure of safety from macroshock, the power supplied to most ORs are ungrounded
- Electrical contacts w/ground can cause injury when they complete the circuit (that permits the pt completes it) but now we isolate the electrical power instead of being grounded, it is UNGROUNDED POWER
- In the OR, numerous electrical devices, together w/power cords and puddles of saline solutions on the floor, make an electrically hazardous environment for both patients and personnel.
- The 120 volt potential difference exists only between the two wires of the isolated power system (IPS) but no circuit exists between the ground and either of the isolated power lines(so circuit can't be completed by pt or staff)
What is an isolation transformer? What does it do?
- This device uses electromagnetic induction to induce a current in the ungrounded or secondary winding of the transformer from energy supplied to the primary winding.
- There is no direct electrical connection between the power supplied by the utility company on the primary side and the power induced by the transformer on the ungrounded (or secondary side).
- Thus the power supplied to the OR is isolated from the ground.provides safety so the circuit can not be completed and cause macroshock to pt or staff
The panel of each isolation transformer is required to have a line isolation monitor, what is this?
- simply electrical current meter that demonstrates the lines meters out power from the ground.
- Barash states,LIM continuously monitors the isolated power to ensure that it is indeed isolated from the ground (has a meter to measure impedance to the ground of each side of the IPS.
- We don’t see isolation transformer we see line isolation monitor on the wall that shows it’s working.
- If there is a short circuit you’re going to see the monitor fluctuate, it will shut off some of our power too.
Why is the line isolation monitor so important?
- If a faulty piece of equipment is connected to the IPS, this will change the system back to a conventional grounded system.
- The faulty piece of equipment will function normally...which is good because it could be life support and we don't want that not functioning.
- BUT we need a warning system to be in place to alert people the power is no longer ungrounded
When would the line isolation monitor (LIM) alarm?
- The LIM is connected to both sides of the isolated power outlet so it’s connected to both primary and secondary coils and is set to alarm when either side has an impedance to the ground of less than 25000 ohms or when max current to that.
- A short circuit could exceed 2milliamps (2 and above it will alarm).
- The LIM is insensitive to currents below 2 milliamps, therefore it will provide NO PROTECTION TO MICROSHOCK, only to macroshock.
___% of all cases of surgical fires have been in an oxygen enriched environment, a common contributor during head and neck surgery is the delivery of large concentrations of oxygen via a facemask
What is MACRO SHOCK? How many amps can cause Vfib via MACROSHOCK?
- large amounts of current flowing through a person, which can cause harm or death
- 100-300 milliamps
What is MICROSHOCK? How many amps can cause Vfib via MICROshock?
- very small amounts of current and applies only the electrically susceptible patient. This is an individual who has an external conduit that is in direct contact with the heart. (ex: pacing wire or a saline-filled catheter such as a CVL or PA line)
- Even minutes amounts of current (microshock) may cause VFib (100 microamps)
How do modern monitors help protect patient from microshock?
- involves electrically isolating all direct patient connections from the power supply of the monitor by placing a very high impedence between the patient and any device.
- This limits the amount of internal leakage through the patient connection to a very small value.
Modern monitors reduce risk of microshock by placing impedence between the patiant and any device which limits the amount of internal leakage through the pt connection to a small value. In order to prevent microshock, the total leakage of OR equipment must be ___microamps.
10 microamps, so if we have a little current going on, as long as it’s under 10 microamps the patient will not be affected
What is tenting?
- Drapes covering the patient result in accumulation of concentrated oxygen under them
- Therefore, in an O2 rich environment, application of an ignition source (such as the electrocautery unit, defibrillator, a hot fiber optic light source, or surgical laser) can regularly ignite this
TRUE or FALSe. Static electricity in the past hospitals would try to decrease static electricity by maintaining humidity at 50%, gets to grade point where instruments aren’t sterile anymore
What does the EPA do?
involved in disinfection and sterilization of devices and procedures
What does the FDA do?
regulates chemical germicides used on medical devices, also requires a manufacturer of reusable product to provide adequate instructions on cleaning and disinfecting
What does OSHA do?
regulates occupational exposure to chemical disinfectants and sterilizers
What does the CDC do?
recommends broad strategies to prevent transmission of an infection in the health care environment
Most resistant type of germs
bacterial spores (some of which are resistant to chemical and physical stresses)
_____ and ______ are the least resistant to chemicals
Hep B and HIV
What is an antiseptic
a substance that may be applied to living tissue, it has antimicrobial activity
What is a bacteriostat?
agent that prevents bacteria growth but it will not kill the bacteria
What is decontamination?
- Process by which contaminated items are rendered safe for personnel who are not wearing protective attire
- A. Reasonably free of (probably) transmitting infection
- B. Reduction of microbial contamination to an acceptable level
- C. Any process that eliminates harmful substances
What is a disinfectant?
chemical germicide that is formulated to be used solely on inanimate objects (NOT HUMANS!)
3 Types of Disinfectants
- High level- kills all organisms including bacterial spores and certain viruses; most of these can produce sterilization with sufficient contact time
- Intermediate Level- kills bacteria including TB, some fungi, most viruses, but NOT bacterial spores
- Low Level- kill most bacteria, NOT TB, some fungi, viruses, and spores
What is sterilization? How many methods of sterilization “that you should be familiar with”?
- destruction of all viable forms of microorganisms
- SIX methods:
- Steam Sterilization (autoclaving)
- Chemical Disinfection and Sterilization
- Gas Sterilization
- Radiation Sterilization (gamma rays)
- Gas Plasma Sterilization
Pasteurization is a sterilization method, describe this
- equipment is immersed in water at an elevated temp for a given period of time.
- It is a disinfecting process that cannot be depended on for sterilization ex. ventilator bellows, laryngoscope blades (first step in sterilization process, this isn’t the only way blades are cleaned)
- Advantage to this method: lower temperatures: there’s less damage to the equipment and also no toxic fumes or residues
Describe Steam Sterilization (autoclaving)
- uses saturated steam under pressure
- it will kill all bacteria, spores, and viruses
- This is the method that is used in OR to clean ALL surgical equipment
Describe Chemical Disinfection and Sterilization
- Utilizes liquid chemical agents and is often performed by soaking an item in the solution
- It is useful for heat sensitive equipment
- Disadvantage: chemicals can be absorbed into the items and cause harm to the patients, cannot be used for all types of equipment, sterility is not guaranteed, some solutions aren’t safe for tissue, will have an unpleasant odor and you will need to avoid prolonged skin contact or inhalation of these vapors
Describe Gas Sterilization
- kills bacteria, spores, fungi, and viruses.
- It is flammable, and is a more complex and extensive process, it is restricted to objects that might be damaged by heat or excessive moisture
- Other complications: due to residual left on sterilized items that may cause skin reactions or laryngeal/tracheal inflammation- ethylene oxide
Describe Radiation Sterilization(Gamma rays)
used for sterilizing disposable products from manufacturers, products are pre-packaged before treatment and will remain sterile indefinitely until package is opened (ex. ETT)
Describe Gas Plasma Sterilization
uses gaseous chemical germicide and gaseous plasma, it is used on packaging materials, plastic, and stainless steel instruments and the one you’re going to hear is called the Sterrad system
Not a single chemical germicide that is adequate for all purposes, some of the more common ones are....
alcohol, iodophores, or cydex
Describe alcohol as a chemical germicide
- intermediate level germicide
- It will kill most bacteria, but not spores, the effect of this is limited due to the rapid vaporization and it’s also flammable
- ex: chlorohexidine
Describe Iodophores as a chemical germicide
combination of iodine and solubilizing agent; principally used at antiseptic
Describe Cydex as a chemical germicide
High level disinfectant that is used in a 1% concentration and it MUST be rinsed thoroughly because it’s a physical irritant and will cause patient issues
Which is most commonly used in OR, monopolar or bipolar?
Describe monopolar (unipolar) cautery
- Current flows thru pt, to a grounding pad, then back to cautery unit itself
- Used to cauterize vessels
- If using this type with a pt that has a pacemaker, place bovie pad away from pacemaker (on thigh for example)
- Can’t use the grounding pad if the patient has metal in their body
Describe Bipolar cautery
- Used for less vascular tissues
- No grounding pad used with this type
- Recommended for a pt with an AICD or PM
- Current is localized and does not go thru pt’s body
- Current goes from cautery pen back to the unit
What monitors do we check during our preanesthesia morning checklist?
- O2 analyzer
- pressure monitor with high and low airway pressure alarms
- pulse ox
- respiratory volume monitor (spirometer)
What is on the anesthesia checklist
- Emergency ventilation equipment
- High pressure system ( O2 cylinder supply)
- Low pressure system (vaporizer levels)
- Test flowmeters- (attempt to create a hypoxic mixture)
- Check scavenging system (bobbin should be inbetween 2 white lines)
- Calibrate O2 monitor (make sure low O2 alarm is working, test RA and > 90%)
- Check that breathing circuit is complete and undamaged
- Verify CO2 absorbent is adequate
- Perform breathing system leak check
- Test vent
- Ensure unidirectional flow valves are working
- Check monitors
- Check final status of machine (vaporizers off, APL valve open, selector switch to “bag,” flowmeters at minimum, suction ready, breathing system ready to use)
When checking the high/intermediate pressure system, what are we looking for?
check O2 cylinder supply- should be at least 1,000 psi, check central pipeline pressures- should be 50-55 psi
How do we verify the CO absorbent is adequate?
at least ¾ white, a little purple is ok
How do we perform a breathing system leak check?
Close APL valve and occlude Y piece, pressurize breathing system to 30 cm H20 with O2 flush, ensure pressure remains fixed for at least 10 secs, then open APL valve and ensure pressure decreases
Who benefits from a PA line?
- CAD with LV dysfunction
- Recent infarct
- Valvular heart disease
- Severe COPD
- Acute respiratory failure
- Acute renal failure
- Aortic-cross clamping
- Sitting craniotomy
- Portal systemic shunt
- Liver transplant
- Severe toxemia
- Placental absorption
Causes of hypothermia
- Ambient temperature below 21 degree Celsius
- Anesthetic-induced interference with the hypothalamic thermostat
- Decreases in basal metabolic rate
What is the Delta EEG rhythm?
(0-3 Hz): deep sleep, deep anesthesia, or pathologic states (brain tumors, hypoxia, metabolic encephalopathy) – very low frequency due to ischemia
What is the Theta EEG rhythm?
(4-7 Hz): sleep and anesthesia in adults, hyperventilation in awake children and young adults – cortical depression
What is the Alpha EEG rhythm?
(8-13 Hz): most common normal rhythm – steady wavelength seen in resting, awake adult with eyes closed
What is the Beta EEG rhythm?
(>13 Hz): when alpha rhythm is disrupted by excitation, a less synchronous higher frequency beta rhythm is seen – mental activity, light anesthesia
TRUE or FALSE. Flow meters are calibrated for specific gases
Flow rate depends on _________ at how low laminar flow and _______ at high turbulent flow.
Does the float rotate in the flow meter?
YES! To minimize the effect of friction between these (gases and tube wall) floats are designed to rotate constantly to keep them in the center of the tube
Malfunctions of flow meters include....
- Debri in flow tube
- Vertical flow tube misalignment
- Sticking or concealment of flow meter at top of tube
Flow meter sequence a potential cause of hypoxia in the event of a flow meter leak, how do we reduce this risk?
- The SAFEST configuration exists when o2 is located in the downstream position. (nearest the vaporizer)
- A potentially dangerous arrangement results when nitrous is located in the downstream position.
Describe the pathways for Oxygen
- 1 supply pneumatically powered bellows ventilator
- 2 Via a regulator and an auxiliary O2 flow meter to be connected to a nasal cannula, ambu bag, etc
- 3. To the O2 low pressure alarm sensor
- 4. Pressure sensitive shutoff valve (fail safe) valve
- 5. To the O2 flush control valve
- 6. O2 flow meters
What is the volume and pressure in the E and H tanks for air?
- E: 1900 psig (625 L)
- H: 2200 psig (6550 L)
What is the volume and pressure in the E and H tanks for oxygen?
- E: 1900 psig (660L)
- H: 2200 psig (6900L)
What is the volume and pressure in the E and H tanks for nitrous oxide?
- E: 745 psig (1590L)
- H: 745 psig (15800L)
What is the pipeline pressure
What is included in the high pressure system?
- 1. Cylinders
- 2. Hanger Yokes
- 3. Cylinder primary pressure regulator
- 4. Cylinder pressure gauge
- 5. Check Valve Assembly
What is included in the intermediate pressure system?
- 1.) Cylinder supply source (45 psig)
- 2.) Pipe line ( 50 -55)
- 3.) O2 pressure failure devices (O2 fail safety & O2 failure alarms)
- 4.) O2 flush valve
- 5.) Flow control valve
What is included in the low pressure system?
- 1.) Flow meter indicator and tubes
- 2.) Check Valve
- 3.) Low flow pressure reducer regulator (if present)
- 4.) Vaporizer
- 5.) Common Gas outlet
Describe the galvanic oxygen analyzer
- Measures the current produced when O2 diffuses across a membrane & it's reduced to molecular oxygen at the anode of the electrical circuit
- The current is proportional to the ppO2 in the fuel cell
- These analyzers require regular replacement of the sensory capsule
- The elec. potential for reduction of O2 results from a chemical reaction and over time, the reactants require replacement
- At a constant light intensity and Hb concentration, the intensity of light transmitted through a tissue is a logarithmic function of the O2Sat of Hb
- The HbO2 is determined by measuring the ratio of infrared and red light sensed by photodetector
What are limiting factors for pulse oximetry
- Absense of pulsatile waveform during extreme hypothermia or hypoperfusion can limit the ability of the oximeter to calculate the SpO2
- Lab co-oximeters can use mult. wavelengths to distinguish other types of Hb (met Hb or COHb)
- Dyes (methylene blue)
- Nail polish
- Ambient light
- Light-emitting dioide variability
- Motion artifact
- Background noise
Increases in metHb or COHb produce an underestimation when SpO2 > ___% and overestimation when SPO2 is < ___%
What can cause increases in exhaled concentration of CO2?
- Increased CO2 production: (hyperthermia, sepsis, MH, shivering, & hyperthyroidism)
- CO2 Rebreathing: exhausted absorber or faulty unidirectional valves
Causes of decreased in EtCO2
- Pulm. hypoperfusion: dec. CO, PE, and congenital R to L shunt
- Leaking shallow breathing
- Rapid shallow breathing
What causes the end-expired CO2 to be absent
- ETT misplacement: extubated or esophageal
- Complete tube obstruction
- Circuit disconnection
- Circulatory Arrest
(Diverting) Aspiration Capnograph
- continuously suctions gas from the breathing circuit into a sample within the monitor
- Compares infrared light absorption in the chamber cells w/those free of O2
- Prone to water precipitation
- Not reuseable!
Non-diverting (flow through) capnograph
- measures CO2 passing through an adapter placed in the breathing circuit
- Too heavey for a child
- Increases dead space
- needs to be washed
what happens if the BP cuff is too big
- False low
- (this can also occur when the extremity is above heart level or after quick deflation)
What happens if the BP cuff is too small?
- False HIGH
- (also happens when applied too loosely or when extremity is below heart level)
What is the proper size cuff
- AHA: Bladder width should ~40% of the circumference of the extremity.Bladder length should be sufficient enough to encircle at least 80% of the extremity
- Kathy: Bladder should extend at least 1/2 around the extremity and the width should be ~20-50% greater than the diameter of the extremity (based on thickness of extremity not length)
Complications of the A line
- Hematoma/bleeding-catheter seperation
- Arterial thrombosis
- Embolization of air bubbles/thrombi
- Necrosis of skin overlying catheter
- Nerve damage
- Loss of digits
- Unintentional intra-arterial drug injection
What are the hydrostatic factors to consider when reading a BP?
10cm above/below heart = 7.5mmHg added/subtracted
Site: more peripheral the SBP increases and the DBP decreases
TRUE or FALSE. BIS is a form of EEG so we could use it instead for a carotid endarectomy
FALSE! it is a form of EEG but we would NOT use it instead!
What is a BIS monitor
- Data measure from EEG is calculated to a single # that correlates to anesthetic level
- Not a MAC meter! DOESN't predict likelihood of movement (if not enough narcotic, pt will move regardless of BIS)
Give the ranges for BIS monitoring
- 60-85: advocated as a measure of sedation
- 40-65: recommended for GA
True or False. Cerebral ischemia can occur without a noticeable difference in the BIS monitor
Cerebral ischemia can produce a loss of consciousness and the BIS monitor may consequently decrease
What are evoke potentials
- Diagnostic tool to eval. certain criteria neuro disorders
- monitor functional integrity of sensory and motor pathways during surgical procedures
- Extremely sm. amplitude (microvolts) elec. potentials generated by nervous tissue in repsonse to stimulation
- (used for spinal surgeries, brachial plexus repair, thoraco AAA repair, epilepsy surgery, etc.)
What are the 4 sensory pathways
- Brainstem auitory evoked responses
- Visual evoked potentials
- Samatosensory evoked potentials
- Motor evoked potentials
Brainstem auditory evoked responses are a type of sensory pathway, what are they?
- Monitor by stimulating cochlea
- Useful in assessing brainstem function in comatose patients
- Surgical procedures of the cerebellopontine angle, floor of the 4th ventricle, or 5th, 7th, or 8th cranial nerve
- Resistant to effects of anesthesia
Visual Evoked potentials are a type of sensory pathway, what are they?
- Produced by flashing light to stimulate the retina
- Records EP over the occiptal cortex
- Assess the integrity of the visual pathway
- Used in resection of pituitary tumors, craniopharyngiomas, or near optic tracts
Somatosensory evoked potentials are a type of sensory pathway, what are they?
- Monitors transmission of EPs through the sensory pathway
- Nerves are median, ulnar, peroneal, or posterior tibial
- Monitor cerebral function or ischemia
- Evaluate spinal cord function
Motor evoked potentials are a type of sensory pathway, what are they?
- Assess descending motor pathways during neurosurgical, orthopedic, or vascular procedures
- Obtained by transcranial electrical or magnetic stimulation or direct spinal cord stimulation
If you are delivering 1L of O2 and 1L of air, what is the O2 concentration being delivered?
- 1L of O2 is 100% O2 and 1L of air is 21% O2
- So if 100+ 21 = 121 then divide by 2, then 60% of O2 is being delivered
What is a laser?
- Light Amplification by Stimulated by Emission of Radiation
- Used for excellent pricision and hemostasis w/minimal post-op edema or pain
How does laser light differ w/other light? (3 ways)
- Monochromatic: possess one wave-length
- Coherent: it oscillates in the same phase
- Collimated: exists aas a narrow parallel beam
What do the Lasers use and side effects depend on?
the wave length (which depends on the medium in which the laser beam is generated)
Laser medium: substance that can be stimulated to metastable state when pumped w/external energy source. Can be either solid, gas, liquid, or semiconductor
For lasers, The ____the wavelength, the greater the absorption of water and less tissue is penetrated
- Therefore CO2 lasers effects are much more localized and superficial than the YAG laser.
- However the solid state lasers (YAG) are more powerful than gas lasers (CO2) because of its wavelength
Difference between a CO2 and a YAG laser
CO2: gas medium, laser produces a LONG wave length. Effects are more localized and superficial (more absorption of water and less tissue penetration)
YAG: solid state, laser produces a SHORTER wave length (more powerful but a larger area)
**This will be a TEST question!
Ways to prevent fires in the OR
- Control various heat sources and prevent them from contacting fuels
- Laser safety protocols
- Allow surgical preps to dry
- Minimize O2 concentration
- Control heat sources (don't let it contact fuel source)
Pre-requisites for a fire
- Flammable agent (fuel): anesthetic agents & bowel gas
- A gas that supports combustion: OR supplies & Oxygen & Nitrous
- Source of ignition: Static electricity and electrical equipment
Why are we so concerned about eye injury during laser surgery?
- Eye is extremely vulnerable to injury from a laser beam because the laser radiation is coherent and all the energy can be focused on a sm. portion of the cornea or retina
- Why we need to wear eye protection ourselves
The ______laser can injure the cornea where the ______laser can injury the retina
What do we do to protect the patients eyes during laser surgery?
- Put saline soaked gauze on patients eyes (after taping them first) and then place the goggles on too.
- Petroleum based lube not used during laser procedures because they can cause burns
What do can we put on the ETT as a safety precaution when using a laser in the airway?
Place metallic tape around the ETT (do this in advance because it still needs to sit for a few minutes)
ETT will support combustion so we use special ETT when doing airway surgery w/lasers. Some are more resistant than others but not one prevents fire in the airway all together. Name the different types
- Polyvinyl: Inexpensive, non-reflective but it has low melting point and is highly combustible (this one is typically used!)
- Red rubber: puncture resistant, maintains structure, non-reflective but highly combustible
- Silicone rubber: non reflective but combustible (turns to toxic ash)
- Metal: combustion resistant, kink resistant but thick walled flammable cuff, transfers heat, reflects laser, and is cumbersome
Besides the ETT preperation, what else can we do as a safety precaution when using a laser in the airway?
- Keep inspired O2 low (O2 analyzer won't let you go less than 30)
- N2O not used (will support combustion)
- ETT cuff is filled w/fluid (saline dyed with methylene blue)
- Limited laser intensity and duration
- Saline-soaked pledgets in airway
- Be aware of where fire blankets, extinguishers, etc. are.
- Have a bottle of Saline ready to pour
What are the actions if a fire happens in the airway?
- D/c use of laser
- Stop ventilation, turn of O2, disconnect breathing circuit, and remove ETT
- Extinguish airway fire (if necessary) w/NS
- Assume mask ventilation w/100% O2
- Reintubate w/smaller ETT and continue anesthetic
- Examine airway, remove debris w/rigid scope
- Examine small/distal airways w/flex scope
- Assess extent of thermal trauma w/ABG/CXR
- consider administration of steroids
- Post-op intubation and administration of O2 (consider trach) if airway burn is present or suspected
- Extubation and administration of O2 by mask if airway damage is minimal or risk of laryngeal edema is low
- Minimum 24hr ICU observation
Cautery is very frequently used by surgeons for cutting and coagulation. How does this work?
Generates ultra high frequency current that passes from the cautery tip through the patient and exits via grounding pad
What are problems associated w/cautery?
- Disturbance in pacemaker function
What is the grounding pad for cautery and how/where should it be placed?
- Bovie (return high current from unit to low current and return it back to cautery unit
- Correct placement: current dispersed over a large area. If grounding pad buckles energy will go to a small area and cause a burn
What type of cautery is most commonly used to cauterize vessels?
Where should you place the grounding pad if the patient has a pacemaker (or any metal in the body)?
Make sure pad is not near pacemaker, place as far away as possible
Describe Bipolar cautery and when it is used
- Used for less vascular tissue
- No bovie/grounding pad
- Used especially for patients w/AICD or pacer. The current will stay LOCALIZED, it will only go from cautery pen and back to cautery unit
What should our emergency ventilation equipment consist of?
Ambu bag, mask, O2 cylinder w/own regulator (oxygen supply seperate from anesthesia machine and pipeline supply)
What are the stressors for our anesthesia practice?
- Chronic fatigue
- Work schedules
- Critical patients
- Fears of litigation
- Productivity demands
- Lack of control
What is wellness?
“state of complete physical, mental, and social well-being”o Not only absence of illness but awareness and understanding
What is the AANA wellness program and focus?
- Acknowledges role of internal and external stressors
- Set objectives
- Raise awareness and educate
- Alert students and CRNAs
What are the s/s of drug abuse and peer assistance?
- Comes to work on days off
- Isolates and withdraws from peers
- Frequent breaks
- Extra call shifts
- Increasing tardiness
- Gradual decline in performance
- Signs out more narcotics that other providers
- Inappropriate drug choices
- Difficulty with authority
- Forgetful, unpredictable, confused
- Frequent illnesses
- Exhibits dishonesty
- Elaborate excuses
- Suffers from tremors or “Monday morning shakes”
- Appears intoxicated at social functions
- Discovered comatose or dead
O2 Flush valve is what part of the pressure system?
- Allow direct communication between O2 high pressure circuit and low pressure circuit (part of the intermediate pressure circuit)
- Enters low pressure downstream of vaporizers
- High pressure O2 source for jet ventilation
O2 flush valve delivers 100% O2 at a rate of _-____L/min
Hazards of the O2 flush valve
- Valve sticks (if this happens, disconnect pt immediately and get ambu bag)
What is the DISS system?
- Developed to provide non-interchangeable connection from medical gas line pipes
- Each connection consists of a body, a nipple, and a nut combination
- Can not interchange them, specific threads, specific sizes, etc.
- Oxygen: more threads
- N2O: wider and less threads
PINs of oxygen and nitrous
- Oxygen: 2 & 5
- Nitrous: 3 & 5
What is the Pin Index Safety System?
used to prevent mix up of gases
However, multiple washers will make pins obsolete and you can still have an error
To prevent delivery of a hypoxic (<21% O2) gas concentrations, there is a fail safe device. How does this work?
- Permits the flow of other gases (N2O, air & volatile) only if there is sufficient O2 pressure to prevent the adminstration of a hypoxic mixture of gases
- Valve is held open when O2 supply pressure is greater than threshold of 20psig
- If the oxygen falls below 20psig, it will shut off all gases or proportionally shut them all off
To prevent delivery of a hypoxic (<21% O2) gas concentrations, there is an O2/N2O ratio controller. How does this work?
Permits the flow of N2O only if there is sufficient oxygen pressure to prevent the administration of a hypoxic mixture of gases
What are some circumstances under which a hypoxic mixture could happen?
- Wrong supply of gas in O2 pipeline or cylinder
- Defective pneumatics or mechanics
- Leaks downstream of flow control valves
- Inert gas administration (such as 3rd gas like Helium)
What is our low pressure alarm
Detects oxygen supply failure at the common gas inlet
What are the causes low vent pressure alarm?
- Minimum airway pressure
- Low airway pressure
- Ventilation failure
- Pressure failure
- Ventilator disconnect
- Minimum ventilatory
- Ventilation pressure
- Threshold pressure
- Peak Airway
- Low pressure
- Low circuit pressure
What is the subatmospheric pressure alarm activated by?
- a pressure that falls below atmospheric pressure by a predetermined amount
- Can be generated by a patient attempting to inhale against a collapsed reservoir bag or increased resistance
Subatmospheric pressure alarm can be generated by a patient attempting to inhale against increased resistance. What are some causes of this?
- A blocked inspiratory limb (during the ventilators expiratory phase)
- A malfunctioning active closed scavenging system
- Suction applied to a nasogastric tube placed in the tracheobronchial tree or to the working channel of an endoscope passed into the airway
- A sidestream gas analyzer
- Refilling of a hanging bellows ventilator bellows
What is causes of the high pressure alarm?
- Increased PIP: Increased TV, decreased compliance
- Increased PIP and unchanged PP: Increased inspiratory gas flow rate & increased airway resistance
Does the high pressure alarm go off if there is a complete obstruction?
- Even in the presence of complete obstruction, this alarm will not be activated if the peak inspiratory pressure does not reach the set limit.
- What will decrease PIP so there is no alarm: High compliance, low resistance, leaks, low inspiratory flow rates, high RR, low I:E ratios, low TV and low FGF
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