Test 1- Week 1 Flashcards

Question

variable-bypass

Answer 1

A specific concentration is created by variable-bypass system, where fresh gas flows over a reservoir of liquid anesthetic and mixes with carrier gas

Answer 2

All modern vaporizers are out-of- circuit (VOC)  Carrier gas is from flowmeter  Anesthetic % is known = precision vaporizer VAPOR IS NOT IN THE PT CIRCUIT

Answer 3

 In the past, vaporizers were in the circuit (VIC) – non-precision  Glass jar containing wicking material  Increase surface area for vaporization  Ensures saturation with anesthetic gas  Variable bypass  Carrier gas is patient’s expired gases  Cannot produce a known anesthetic %  Not temperature compensated  Not currently recommended

Answer 4

 Temperature between 15-35 C.  Flow rate between 0.5 and 10 L/min  Back pressure associated with positive pressure ventilation and use of flush valve

Answer 5

 Require no external power (except desflurane)  Routine maintenance is required and must be performed by a qualified technician  Mounted on a “back bar” on the machine  Cannot be tipped – must be emptied before transporting

Answer 6

What would happen?  Depends on vapour pressure and potency of each agent  Iso in sevo vaporizer could produce a lethal concentration (higher vapour pressure AND higher potency)  Drain and run 1 L/min O2 until completely dry

Answer 7

Vaporizer tipped  What would happen?  Anesthetic may enter the bypass channel and deliver a high concentration  Run 1 L/min O2 through machine with vaporizer off

Answer 8

Re-breating System  i.e. Circle/Y-piece

Answer 9

1. Re-breating System  Universal “F”

Answer 10

2. Non-rebreathing System  i.e. Mapleson D

Answer 11

 One-way (circular) gas flow  Inspiratory and expiratory breathing limbs  CO2 absorber prevents rebreathing of excessive CO2  Patient re-breathes inhalant and O2 via inspiratory limb

Answer 12

**_ Advantages_**  Lower fresh gas flow rate  Saves $$$  Decreases environmental pollution  Patient breaths warm, humidified gases (re-breathes) **_ Disadvantages_**  More components  more potential for leaks  ↑resistance for smaller patients (\< 3-10 kg)  [anesthetic gas] changes SLOWLY  Due to lower O2 flow rate (more on that in the inhalant lecture!)

Answer 13

One-way or Unidirectional Valves  Inspiratory  Expiratory

Answer 14

_Oxygen Flush Valve:_  Bypasses vaporizer!  DILUTES gases in breathing system and reservoir bag  Delivers oxygen directly to the breathing system 35-75 L/minof100%oxygen _CAUTION:_  Avoid activation with patient attached to system  NEVER NEVER NEVER w/non-rebreathing system!

Answer 15

Fresh Gas Inlet:  fresh gas (not breathed) = Hose that provides breathing system with: oxygen +/- inhalant  MUST check this connection when changing breathing systems  It is SHARED btw re-breathing and non-rebreath

Answer 16

 Adjustable Pressure-Limiting (APL) Valve:  Aka pop-off valve  Limits pressure buildup in breathing system  **OPEN ALWAYS unless:**  Pre-use machine check (MUST OPEN when done!)  Must close to administer positive pressure ventilation  Manual or controlled  Closed APL valve  ↑ pressure in breathing system cardiopulmonary injury  Can result in patient DEATH!

Answer 17

 Breathing System Pressure Gauge:  Measures pressure in the breathing system  Should be ZERO (0)!  Exceptions:  unless performing leak checks (pre-use check)  providing positive pressure ventilation (IPPV)

Answer 18

 Soda lime most commonly used today  Absorber assembly has canister to hold soda lime, 2 ports for connecting breathing tubes, fresh gas inlet, +/- unidirectional valve mount and bag mount  What is soda lime?  Calcium hydroxide with small amount of sodium hydroxide and color indicator  Indicator = ethyl violet (fresh white; exhausted purple)  Carbon Dioxide Absorber (continued...)  Monitor time (limited)  Heat reaction and color change when active  When filling:  Do not pack tightly, avoid dust of broken particles  Check gaskets & seals as a source of leaks (esp if dust particles present)  Signs of Exhaustion  Increase end tidal CO2  If at a light enough plane of general anesthesia:  Increased ventilation  Increase in HR & BP initially (then decrease)  Rebreathing (seen on ETCO2)  Respiratory acidosis  Red mucous membranes (carbon monoxide production and inhalation)

Answer 19

 Functions  Observe ventilation, inspiratory reserve, administer manual positive pressure ventilation  Calculation of bag size:  Formula = tidal volume (10-20 mL/kg) x 6  Round UP if in between sizes  Example:  10 kg canine patient x 10-20 mL/kg x 6 = 600mLround up to 1L bag

Answer 20

Oxygen Flow Rates:  MANY different flow rates may be used with this type of system  Typically in small animals  Induction & Recovery = (HIGH)50-100 mL/kg/min O2  Maintenance =(SEMI-CLOSED)20-50 mL/kg/min O2  Typically in large animals  Induction & Recovery = 20-50 mL/kg/min O2  Maintenance = (LOW)10-20 mL/kg/min O2

Answer 21

 Components:  Fresh gas  Nonrebreathing tubes  APL (Mapleson D) OR open/close (Mapleson F) valve  Reservoir bag  Missing components:  Soda lime canister  Unidirectional valves  O2 flush button (NEVER USE WITH THIS SYSTEM!)

Answer 22

**_ Advantages_**  Very light, with minimal dead space or resistance to ventilation (good for patients \< 3-10 kg; 5kg @ RUSVM)  Fewer components = fewer potential for leaks  [anesthetic gas] changes rapidly (high gas flow) **_Disadvantages_**  High gas flow rates  $$$ to run in larger patients  ↑ environmental pollution  No rebreathing = gases not as warm or humidified

Answer 23

Oxygen Flow Rates:  HIGH when compared to rebreathing systems  \*O2 flow is mechanism for eliminating CO2 !\*  Must be a least 2-3 x tidal volume in most cases  200-300 mL/kg/min O2  What monitor would help determine if rebreathing CO2 via O2 flow rate too low?

Answer 24

Indications:  Maintain patent airway  Protect airway from foreign material  Blood, regurgitation  Provide intermittent positive pressure ventilation (IPPV)  Apply tracheal or bronchial suction  Administer oxygen  Deliver inhalant anesthesia

Answer 25

 Reduced anatomical dead space  IF correct size and position of tube  Dead space = air WITHOUT gas exchange  Maintain inhalant anesthesia with minimal environmental contamination  Properly inflated cuff

Answer 26

 Oral  Nasal  External Pharyngotomy  Tracheostomy

Answer 27

Laryngoscope:  Makes intubation safer and easier!  Allows visualization of airway  Light source  Apply light pressure to base of tongue, just rostral to epiglottis  Apply gentle pressure ventrally, this tilts larynx, opens glottis, & frees soft palate from epiglottis (if it was entraped)  Do NOT apply significant pressure directly on epiglottis!  Risk = fracture of hyoid apparatus

Answer 28

 Non-recirculating room ventilation system  Charcoal absorption (F air canisters)\*  Does NOT scavenge nitrous oxide  Piping direct to atmosphere (i.e. via window)

Answer 29

Piped vacuum (white drop and tubing)\*

Answer 30

ADVANTAGES: * Absorbs hydrocarbons * Does not release to ozone • Portable DISADVANTAGES: * Does not adsorb N2O * Absorbs hydrocarbons only! * Flow- limited * Added Resistance * Weigh before use * record number of grams * Discard when 50 grams + or 8-12 h of use thus, FINITE USE