Sait Anesthesia Midterm Cram

Front 1

N2O is stored as a liquid under about ____ PSI.

Back 1

750

Front 2

Gases are regulated to a typical operating pressure of ___ PSI.
Some machines further reduce operating pressure to ≈ ___ PSI.

Back 2

50

16

Front 3

Label

Back 3

Front 4

label

Back 4

Front 5

Back 5

Front 6

Infrared analyzers can detect _______ gas.
Ionizing leak detectors identify __________________---require frequent calibration.
Mass spectrometers, gas chromatography and photo-spectrometers can also be used.

Back 6

nitrous oxide

halogenated hydrocarbons

Front 7

The circle system advantages

Back 7

This is the most widely used circuit in use today.

Low flow rates are needed from the fresh gas outlet (economy).

Warming and humidification are achieved from the reactions in the CO2 absorber

Reduced chance of overflow and therefore reduced pollution of theatre

Front 8

Low flow technique
The operator can allow _____ LPM of fresh gas into the circuit to produce minimal re-breathing. This is fine as long as a minimum of ___% O2 is maintained in the circuit

Back 8

2 to 3

25

Front 9

Flows of _____mL/min of pure oxygen, are all that is needed to maintain metabolism. This low a flow will require that agent concentration is monitored very carefully (under target concentrations are possible).

Back 9

200 to 300

Front 10

No CO2 absorber in the circuit therefore flow must be high enough to meet pts. minute ventilation. (100mL/kg)
Not practical for controlled ventilation

Back 10

Magill Circuit

Front 11

No CO2 absorber in the circuit therefore flow must be high enough to meet pts. minute ventilation.
Plastic version is used in some head and neck surgery. Somewhat better in PPV than Magill.

Back 11

Bain Circuit

Front 12

Very simple in design
Low resistance
Was once popular for pediatrics
Fresh gas flow of 2 to 3 times the normal minute ventilation is required to eliminate re-breathing.
To and Fro: Has CO2 absorber near Pt. therefore limited resistance---cumbersome---not popular.
Non-rebreathing circuit: Reservoir bag should be nearly full before inspiration and not quite empty after

Back 12

Jackson Reese (modified T-Piece)

Front 13

Which circuit is which

Back 13

Front 14

_____ is a coaxial circle system, with the inspiratory limb contained within the expiratory. Like a Bain, it is less bulky, and may offer more heat and humidification of the inspired gases. Like the Bain, disconnection or kinking of the inner limb causes a huge increase in dead space and respiratory acidosis dioxide from the patient's exhalations

Back 14

King Circuit

Front 15

EtC02 Mainstream:

Back 15

Inline with subject’s exhaled gas via ETT
Can pull on the airway (heavy)
Slight increase in deadspace

Front 16

EtC02 Sidestream:

Back 16

Sample rate ~150mL/min
Slight lag in response time
Slight increase in deadspace
Sample line can occlude with condensation, some units have heaters to reduce condensation

Front 17

Back 17

Front 18

Shallow and Rapid breathing
PeT02

Back 18

Partially mixed alveolar CO2 with dead-space gas
Very small Vt may cause ↑ PACO2 but a ↓PETCO2.
This may hinder usefulness during weaning etc.

Front 19

Leak around ETT

Back 19

unchanged PACO2 but ↓PETCO2

Front 20

Leak in sampling system

Back 20

unchanged PACO2 but ↓PETCO2

Front 21

Increase in V/Q -Ventilation in excess of Perfusion
Decreased PACO2
Examples

Back 21

Pulmonary Embolism
Decreased C.O.
Hypovolemia
Severe Hypotension
Cardiac Arrest

Front 22

Increased PETCO2

Back 22

Decreased Alveolar Ventilation (VA)
Hypoventilation
Decreased minute ventilation (VE)
Increased CO2 production: shivering, pain, fever etc
VA=VE-VD

Front 23

Decreased PETCO2

Back 23

↑ VA ----well above metabolic need
Very low Vt, approaching dead-space volume
Low perfusion / emboli / ↓ cardiac output

Front 24

Back 24

Disconnected circuit or apnea.

Front 25

Back 25

Hypoventilation
--high plateau

Hint 25

May also see rising slow speed baseline

Front 26

Back 26

Increased CO2 production, (exercise, stress), decreased removal, perhaps improving CO, if increasing to near normal.

Front 27

Back 27

Early airway closing
Small airway disease
Eg. COPD

Front 28

Back 28

Erratic exhalation
Post op ?

Back 29

Opening of previously closed lobe/lobule. ?

Front 30

Back 30

Opening of previously closed lobe/lobule. ?

Front 31

Back 31

Re-breathing CO2

Front 32

Back 32

Very small Vt. Didn’t trigger vent.

Good sized Vt interspersed with Vent breaths.
R Rate?
Mode ?

Front 33

Why is PetCO2 possibly erroneous during a SBT?

Back 33

Weaning pts seldom hyper-ventilate if pain/fear/anxiety is under control.

Front 34

Anesthesia is ________

Back 34

“A state of reversible loss of sensation and unconsciousness”.

Front 35

Stages of anesthesia
Stage1.
Stage2.
Stage3.
Stage4.

Back 35

Stage 1--Analgesia: Beginning of drowsiness to the loss of the eyelash-flick response.
Stage 2--Excitement: Agitation, irregular resps, delirium, salivation, dilated pupils, leading to regular (or brain stem) resps.
Stage 3: Surgical Anesthesia: Four Planes
Stage 4: Impending Death: Circulatory collapse signifies medullary dysfunction.

Front 36

Planes of Surgical Anesthesia
Plane 1.
Plane 2.
Plane3.
Plane 4.

Back 36

Plane 1: Regular resps, REM
Plane 2: Cessation of REM to partial paralysis of the intercostal muscles.
Plane 3: From partial intercostal to full intercostal paralysis.
Plane 4: From full intercostal paralysis to full diaphragmatic paralysis, and therefore apnea.

Front 37

3 Main Components of Anesthesia

Back 37

1)Unconsciousness
Patient may well be oblivious to all sensation but autonomic reflex to pain can still occur.
2) Analgesia
‘Areflexia’---reaction to pain, tachycardia, diaphoresis, etc are reduced or absent.
3)Muscle relaxation
Surgery on extremities requires minimal relaxation where thoracic/abdominal requires profound relaxation of all muscle groups.

Front 38

Regional Blood Flow

Back 38

Vessel rich viscera; 70%
Brain, heart, liver, kidney
Muscle; 25%
Adipose tissue; 4%
Vessel poor tissue; 1%
Skin, cartilage, bone

Front 39

Back 39

Front 40

Ketamine (Ketalar)

Back 40

Produces a dissociative mental state:
 Catalepsy---trance-like state with muscle rigidity
 Sedation
Amnesia 
Analgesia

Hint 40

Given IV or IM in 1-2 mg/Kg dose over 1 minute.
Duration of action is 5-10 minutes.
Converted in liver and excreted by kidneys.
Pt can maintain airway, used in burns, Peds Dx.
BP (20-40mmHg), and HR, may  ICP
Pts need dark, quiet room to recover as can cause hallucinations/bad dreams (emergence delirium).

Front 41

Propofol (Diprivan)

Back 41

Loading dose; 1.5 to 2.5 mg/kg
Rapid redistribution and elimination make it helpful in out-patient procedures.
Anti-emetic,
Lack of cumulative effect is helpful for total IV anesthesia.
May cause transient apnea with reduced response to O2 and CO2 ---no bronchospasm (maybe broncho dilation).
May cause vivid dreams and sexual fantasies during emergence.

Front 42

Thiopental (Sodium Pentothal®)

Back 42

Short acting barbiturate used to induce unconsciousness. No analgesic action.
Slow injection to allow for ‘dose to action titration’.
3 to 5 mg/Kg used for initial induction, action only lasts 5-10 minutes or so as redistribution sends more agent to muscle mass.
Thiopental causes a cerebral oxygen demand, myocardial function, and possibly vascular tone leading to hypo-tension.
May be associated with airway reactiveness and therefore is not used with asthmatics etc.
Has been used by shadowy Eastern European secret agents to get secrets etc. out of low level secretaries in Brussels. (Truth serum).

Front 43

Diazepam (Valium)

Back 43

Widely used tranquilizer used primarily for pre-anesthetic sedation.
Is a mild muscle relaxant and anti-convulsant.
Metabolized by the liver and excreted by the kidney (70%) & bile/feces (30%).
Prolonged effect due to metabolites having nearly as strong an effect as the original drug.
Causes pain at peripheral injection site. Better to infuse in a central line.

Front 44

Midazolam (Versed)

Back 44

Stronger cousin of diazepam. (2 to 3 times)
0.1 to 0.3 mg/Kg dose.
Has the same pharmacological action plus is an anterograde amnesiac. Pts may seem awake during procedure but have little or no memory of the event afterwards. Useful in cardio-versions, intubation, bronchoscopy etc.
No pain at injection site.
Duration of action is 15 minutes---longer than thiopental but less than valium.
Metabolized by liver---excreted by kidneys
Little effect on BP, RR, cerebral blood flow, ICP

Front 45

Etomidate

Back 45

Loading dose: 0.2 to 0.3 mg/kg
Short duration of action: 3 to 8 minutes
No analgesia, minimal cardio vascular effects.
Some adrenal suppression, which may be advantageous in some pts.).
Potent cerebral vasoconstrictor.
Possible alternative to Propofol or thiopental

Front 46

MAC?

Back 46

Definition: Minimum Alveolar Concentration. “The minimum concentration of an agent needed to prevent movement in 50% of patients when a standard incision is made”.
This obviously infers that 50% will move. If we increase a MAC by 30 %, 95% of patients will not move during a painful incision.
MAC is the standard measure of an agents’ strength. The lower the MAC, the stronger the agent.

Front 47

MACs of Inhaled Anesthetics

Back 47

Methoxyflurane 0.16%
Halothane 0.77%
Isoflurane 1.15%
Enflurane 1.70%
Sevoflurane 2.00%
Desflurane 6.00%
Nitrous Oxide 104.00%

Front 48

Increases MAC

Back 48

Hyperthermia
Drug use
Chronic alcohol abuse
Amphetamines
CNS stimulants

Front 49

Decreases MAC

Back 49

Advanced age
Hypothermia
Severe hypotension
Other agents; opiates,valium
Acute drug or ETOH intox.
Pregnancy
Hypothyroidism
High PCO2, Low PO2

Front 50

Nitrous Oxide facts

Back 50

Nitrous Oxide is 34x more soluble than nitrogen gas.
Second gas effect
Diffusion hypoxia during emergence.
Closed air spaces may double in 66% N2O

Front 51

Back 51

Front 52

Soluability of halogenated hydrocarbons

Back 52

High: Halothane
Enflurane
Isoflurane
Sevoflurane
Desflurane
Low: Nitrous Oxide
(HE IS Dumb N2O?)

Front 53

the enzyme _____ takes out most anesthetic agent

Back 53

P450 cytochrome

Front 54

Rocuronium reversed by

Back 54

Neostygmine