Anaesthesia Flashcards
(29 cards)
Factors affecting choice of breathing system (6)
resistance
rebreathing
fresh gas flow requirements
mechanical dead space
circuit drag
cleaning and maintenance
Circle
- rebreathing
- soda lime
- low fresh gas flow requirement - 10ml/kg/minute
- higher flow at start to avoid alveolar hypoxia from dissolved nitrogen in blood
- economical use
- expensive to buy
- increased resistance
- unidirectional valves prevent mixing - need maintenance
Magill
flow = 1*minute volume
can’t be used for IPPV
Lack
flow = 1*minute volume
either tube inside tube or parallel
can’t be used for IPPV
Mini Lack
flow = 1*minute volume
<10kg
parallel tubes
can’t be used for IPPV
T-Piece
flow = 2-3*minute volume
long tube, t connector, short tube with bag
<8kg
can use for IPPV
Bain
flow = 2-3*minute volume
co-axial tube
7-10kg
Can’t use for IPPV
Humphrey ADE
Lever up - lack
Lever down - t-piece
Circle
Can use for IPPV
Monitoring - temperature
hypothermia
rectal thermometer or oesophageal thermoprobe
core-periphery difference - early CV problem sign
low temperature –> increased pain, increased infection, delayed recovery
Causes of temperature fall (7)
Vasodilation
reduced shivering
reset thermoneutral point
open body cavity
cold gases
dry gases
wetting and prep
Monitoring - Pulse
Femoral
dorsal metatarsal (disappears with hypotension)
lingual
auricular
Monitoring - Pulse Oximetry
% oxygen saturation of hemoglobin
accuracy affected by - circulation, ambient light, movement of probe, pigmented skin
probe design not always suitable
Monitoring - ECG
to detect arrythmia
Monitoring - Capnography
CO2 breathed out
info on cardiac and respiratory function
info about - rebreathing, cardiac oscillations, ETT obstruction
increase ETCO2 - hypoventilation
decreased ETCO2 - hyperventilation
sudden drop - cardiac arrest
Monitoring - Blood Pressure
used with HR to determine cardiac output
non- invasive - sphygomanometry, oscillometric, doppler
invasive - cannula for direct BP measurement
Decreased blood pressure causes - anaesthesia (4)
IV fluid loss (hemorrhage)
failing myocardial function
sepsis
relative hypovolemia - vasodilation (sepsis, drugs)
Monitoring - CNS
eye position
jaw tone
EEG - electrical output from brain (bispectral index from 100 (awake) - 60 (general anaesthesia) - 0 (flat line/dead))
Common problems - recovery
Prolonged recovery - hypothermia, too much pre-med, too deep during maintenance, hypoglycemia, choice of inhalant, choice of induction agent
Airway obstruction - debris or gauze, body fluids
Agitated recovery - inadequate pre med or analgesia
BOAS patients
sedate for recovery
supplementary oxygen
leave in IV
leave in ETT until sat up
retube if - cyanosis, distress, low SPO2, paradoxical breathing
ETT
Red rubber - opaque, high pressure seal so can irritate, crack easy
PVC/silicon - less prone to kinking, non-irritant, less pressure, transparent
Armored - coil of wire through - kink resistant, need stylet to place, can be damaged if bite down, can’t reduce dead space
Cole Patter - human pediatric - exoticss
cats - lidocaine sprat
cuff with pilot balloon
Supraglottic airway devices
sit above larynx and envelopes
cats and rabbits - v-gels
Complications - ETT (5)
high pressure/low volume - tracheitis or pressure necrosis
disconnect when moved
leaks
over insertion
improper cleaning - infection, irritation
IV placement
cephalic
saphenous - brachycephalics
jugular - right side, sampling
auricular - peripheral - rabbits and floppy ear dogs
Complications - IV placement (5)
extravasation
thrombosis
thrombophlebitis
emboli
exsanguination
