MEMORIZE FOR QUIZ 5 BASICS

-mapleson req high FGF to diminish rebreathing
-circle systems can use low FGF b/c of the absorber

Advantages:
Simplicity of design
Portability
Ability to change anesthetic depth rapidly
Lack of rebreathing of exhaled gases
Disadvantages
Lack of conservation of heat & moisture
Limited ability to scavenge waste gases
High requirements of fresh gas flow

MAPLESON E

Most efficient design during spontaneous ventilations since a fresh gas flow rate equal to minute ventilation will be enough to prevent rebreathing

Can be used during controlled ventilation

Fresh gas inlet and overflow valve are opposite of Mapleson A
**BAIN is a modified mapleson D

Co-axial (tube within a tube) version of Mapleson D
Fresh gas flow required to prevent rebreathing:
Spontaneous: 2 times minute ventilation (300 ml/kg/min)
Controlled : 70 ml/kg/min
Benefit is humidification of exhaled gases. Kinking of inner tubing and ventilated patients disadv

Jackson Reese modification of the Mapleson E system (Ayres T-Piece
DISADV Short tubing if it becomes occluded it has no where to go.

For CV: D>B>C>A
Dead Bodies Can’t Argue
For SV: A>D>C>B
All Dogs Can Bite

Can be converted to semi-open, semiclosed or closed dependent on fresh gas flow
Easily scavenged to avoid pollution of OR environment

Incompetent valve will allow rebreathing of CO2 (unidirectional valves)
APL valve
Controls the amount of gas in the system

Present when FGF into a circle system is decreased sufficiently to permit closure of the APL valve and all exhaled CO2 absorber
FGF is 150-500 ml/min, which satisfies the patient’s metabolic O2 requirements of 150-250 ml/min and replaces anesthetic gases lost through tissue uptake
Advantages:
Maintains humidification
Less pollution of waste gas since maintained in system (APL closed)
Disadvantages:
Unknown gas concentrations
Unpredictable amounts of oxygen

Thyroid
Cricoid
Epiglottis
2 arytenoid
2 corniculate
2 cuneiform
*3 SINGLE AND 3 PAIRED

Articulate with the posterior larynx and are the posterior attachments for the vocal cords

Attach anteriorly to the thryoid cartilage

Cricoid

vocal cords

Supplied by the branches of vagus nerve (CN X)
Internal and external superior laryngeal nerve
Recurrent laryngeal nerve

Extrinsic
Connects larynx to its anatomic neighbors
Intrinsic
Move laryngeal cartilages and affect glottic movement
Open cords during inspiration
Close cords during swallowing
Alter tension of cords during phonation

Posterior cricoarytnoids: Abduct vocal cords
“Pca”: pulls cords apart
Lateral cricoarytnoids: Adduct vocal cords
Cricothyroids: Increase vocal cord tension (tenses the cords)
Thyroarytnoids: reduce cord tension (relaxes the cords)
Last two are functions of phonation

Internal: (sensory) sensation from epiglottis to VC’s
External: (motor) cricothyroid muscle

(Motor) Supplies all intrinsic muscles of the larynx except the cricothyroid muscle
(Sensory) below VC’s and trachea

hypoglossal
SENSORY
Epiglottis (anterior surface/vallecula)

All muscles of larynx except cricothyroid

Adductors of vocal cords

Relaxers of vc

Weakness and huskiness
Cords can not be tensed
Which muscle is paralyzed

Hoarseness

Bilateral nerve palsy
Aphonia
Airway obstruction (acute)

Stretch receptors in posterior tracheal wall
Regulate rate and depth of breathing
Dilatation of upper airways and bronchi by vagal efferent activity
Irritant receptors lie all around the trachea
Cough receptors

FiO2 increases by 3-4% per liter of O2 given up to 40-50%

Class I
Soft palate, tonsillar pillars, uvula
Class II
Tonsillar pillars and base of uvula hidden by base of tongue
Class III
Soft palate visible
Class IV
Soft palate not visible

delivers O2 flow rates from 6-15 L/min, providing FiO2 of 35-65%

air entrainment mask; delivers FiO2 up to 50%

simple mask with valveless reservoir bag and exhalation ports; can deliver FiO2 up to 80%

simple mask with reservoir bag and unidirectional valve; can deliver FiO2 up to 95%

posterior pharyngeal wall up against tongue and epiglottis

1 neonates / infants up to 5 kg
1.5 infants 5-10 kg
2 infants / children 10-20 kg
2.5 children 20-30 kg
3 children / small adults >30 kg
4 average adult (~50-69 kg)
5 large adult (>70 kg)

< 20 cmH2O

Tip advanced to vallecula

Advanced to lift epiglottis

17 - 23 mm Hg

T4-6

T5

Adult female = 7.5; adult male = 8.0
Newborns: 3 - 3.5
Newborn to 12 months: 3.5 – 4.0
12 to 18 months: 4.0
2 years: 4.5

DEEP extubation 1-1.5 MAC on board. If not they will laryngospaMust reverse all muscle relaxants and patient is breathing spontaneously with an acceptable respiratory rate and depth
Difficult mask ventilation, intubation, risk of aspiration, or surgery that produces airway edema are contraindications to this technique
RSI are not candidates.

Pulling forcefully against a closed glottis
Also called postobstructive pulm. edema
Laryngospasm or obstruction
Negative intrapleural pressure
Incr. venous return to R heart decr output. Incr blood in pulmonary system
Pulmonary edema is the result

Higher incidence in children
Excitatory contraction of adductor muscles
Causes
Hyperventilation and hypocapnia
Light anesthesia and presence of stimulation / secretions
Partial spasm
Some air movement
Crowing/phonation
Paradoxical chest movement
Complete
No air movement
Paradoxical chest movement
ID quickly

Jaw tilt, first thing to do is gentle positive pressure
REMOVE STIMULI - Pain, Secretions, Airway
Gentle positive pressure with 100% O2
Deepen Anesthesia –
lidocaine 0.5-1 mg/kg OR other pharmaceuticals
SCh 0.1-0.5 mg/kg
Potential problems:
Hypoxia
Negative-pressure pulmonary edema (NPPE)

S”: suction : must be connected, within reach & ready to use
“O”: Oxygen: Check wall suction and back-up cylinders. Verify presence of ambu/mask in room. Attach and check circuit; calibrate O2 analyzer; test flow meters; perform leak test; check scavenger; check ventilator
“A”: Airway: gather your intubation pack: Oral airways, laryngoscope, blades, ETT w/ stylet, syringecheck blade and ETT balloon
P”: Pharmaceuticals: prepare the following:

3cc syringe for versed (labeled); 3-5cc syringe for fentanyl (labeled); 3cc syringe for reglan if needed

Prepare TPL or 20-35cc syringe for propofol; or 10 cc syringe for etomidate; 10cc syringe for suxx (20mg/cc); syringe for non-depolarizer (5cc for rocuronium or atracurium; 10cc for vec or panc)….Vec needs to be reconstituted

bristojet of lidocaine or 5cc syringe for 2%; 3cc syringe of atropine *(1mg/cc or 0.4mg/cc)*; 3cc syringe of glycopyrolate (0.2 mg/cc); 5 or 10cc syringe for ephedrine (draw up either 4cc or 9cc of saline then 1cc of ephedrine (50 mg) for conc= 5mg/cc or 10mg/cc)

Neosynephrine: you can draw up 0.1cc of phenylephrine 1% in a TB syringe and add it to 9.9cc of saline in 10cc syringe. Final conc.= 100 mcq/cc

Exhaled volume
Inspired oxygen, with a high priority alarm within 30 seconds of oxygen falling below 18% (or a user-adjustable limit).
Oxygen supply failure alarm
A hypoxic guard system must protect against less than 21% inspired oxygen if nitrous oxide is in use.

DISS protected

Enters at a PSI (pressure per square inch) of 45-55
Inlets are indexed for specific gas
DISS (Diameter Index Safety System) – non-interchangeable connections

from the pipeline inlet to prevent reverse flow of gases
thereby avoiding flow of gas from machine to wall supply

PISS (Pin Index Safety System
Here the pressure from the cylinder (2000psi) is reduced to 40-50 psi.

This system prevents misconnection of a cylinder to the wrong yoke.

Free floating valve (opens & closes with pressure)
Prevents retrograde gas flow
Allows change of cylinders during use
Minimize gas leaks to atmosphere if a yoke is empty
Minimize trans-filling of gases
Prevents a full cylinder from emptying into an empty cylinder
Prevents wall oxygen from entering an empty cylinder

multiply by 0.3 to convert psi to Liters

~45 psig downstream of the regulator

remaining O2 volume in the cylinder by the rate of O2 consumption

cylinder pressure by 2200 psig then multiplying by 660 L

O2 flowmeter rate + (minute ventilation)

Whatever the flow meter is set at.

get close together and form a liquid
Above critical temperature, the molecules will not get close enough and will stay in a gaseous state

Oxygen : -119 degrees C
N2O : 39.5 degrees C

When O2 supplied at ~50 psi it holds open this valve which allows N2O to flow to the flowmeter.
Remains open as long as psi remains >25, if it falls below 25 psi N2o flow is shutoff

machine outlet to circuit
O2 flush of 35-75 L/min

Activated when O2 falls below 28 psi
Alarms sounds before 25 psi, the point at which N2O flow will cease

Gas pressure is decreased to a constant pressure of 16 psi as flow from wall varies at times between 40-50psi
After passing 2nd stage pressure regulator, sits in “stand by” at flow control valve

 O2 flow will incr.
If you incr. O2 flow; N2O will not incr.
If you decr. N2O flow; O2 flow will not decr.

Agent specific, precisely calibrated to compensate to changes in temperature and variations of gas flow

“hlh” Higher vp agent in Lower vp vaporizer chamber higher conc delivered
“lhl” lower vp agent in higher vp vaporizer chamber lower conc delivered

Made specifically for Desflurane
Vapor pressure of Des is 3-4 x’s that of other inhaled anesthetics
Boils at approx. 22.8 degrees C
Electrically heated
To approx. 39 degrees C
If not heated the large amounts of desflurane required (d/t MAC value 4-9 x’s other IA’s) would cause excessive cooling of the vaporizer making conventional temperature compensating mechanism ineffective
Pressurized
At room temperature ~20 degrees C desflurane’s vapor pressure is near 1 atm
Pressurizes to approx. 2 atm
Controls amount of desflurane output

Limits amount of pressure inside the patient’s lungs during manual ventilation
If pressure reaches the setting of the APL knob, the valve opens and allows excess gas to escape to the scavenging system
Turning knob to right (closing) increases the pressure
Turning to left (opening) decreases the pressure

Sodium Hydroxide 4%
Potassium Hydroxide 1%
Calcium Hydroxide 95%

Calcium Hydroxide 80%
Barium Hydroxide 20%

Carbonates + Water + Heat

Total gas flow rates below 1 L/min
Use of baralyme rather than soda lime
High absorbent temperatures
High concentration of sevoflurane
Drying of the carbon dioxide absorbent
Fresh soda lime
Machine on all night
Length of anesthetic

Desflurane, isoflurane & enflurane with absorbents produces carbon monoxide.
Higher levels with desflurane, then enflurane, then isoflurane

Use of baralyme rather than soda lime
Higher temperatures in absorber
Dry absorbent***
High anesthetic concentrations
Increase length of time

manual or mechanical ventilation. Isolates aPl valve from rest of system

sum of the tidal volumes in one minute

: the period between the beginning and end of inspiratory flow

period from the end of inspiratory flow to the start of expiratory flow

period of time between the start of inspiratory flow and the beginning of expiratory flow, or it is the sum of the inspiratory flow time and the inspiratory pause time.

time between the beginning and end of expiratory flow

interval from the end of expiratory flow to the start of inspiratory flow

time between the start of expiratory flow and the start of inspiratory flow or it is the sum of the expiratory flow time and the expiratory pause time

Turn the flow rate down and then it will try to push that 700 cc of air into lung SLOWER.

the ratio of inspiratory phase time to expiratory phase time

volume of gas per unit time that passes from the patient connection of the breathing system to the patient

volume of gas per unit time returned from the patient during the expiratory phase

pressure difference per unit flow across the airway; it usually increases as flow increases

ratio of a change in volume to a change in pressure

driving gas
Contemporary bellows require both

breathing system gases from driving gas

Most commonly used
Rise (fill) during expiration and Fall (empty) during inspiration

Unrecognizable patient disconnection
The bellows in this type will continue to fill and empty even when the patient is disconnected from the ventilator
**less safe

Driving Gas – outside the bellows
Patient Gas – inside the bellows

ETCO2 and PIP)

(MV/RR=VT

N2O : 25 ppm
Halogenated agents: 2 ppm
Halogenated agents with N2O : 0.5 ppm

active most common, uses the hospital suction system)

Connects to the hospital suction system
Positive & negative pressure relief valves protects the patient from the negative pressure of the vacuum system and positive pressure of an obstruction in the disposal system
3 liter reservoir bag is present which hold excess gas until it can be removed
Vacuum control valve is adjusted to 10-15 L of waste gas per minute

Interfaces with the hospital ventilation duct
Relies on the build-up of gases in the bag to passively empty into the hospital ventilation system

Consists of those parts that receive gas at cylinder pressure
Hanger yoke
Hanger yoke check valve
Cylinder pressure regulator
Cylinder pressure guage

Receives gases at relatively low and constant pressures (35-75 psig / pipeline pressures)
Pipeline inlets and pressure gauges
Ventilator power outlet accessory
O2 flush valve
Supply failure alarm system
Second stage pressure regulator
Flowmeter valves

Components distal to the flowmeter needle
Flowmeter tubes
Vaporizers
Temperature compensating bypass valve
Common gas outlet
This is where we do the turkey baster test. O2 flush valve is part of the intermediate system but the gas comes out of the common gas outlet