Thoracic PPT Flashcards
Ventilation (V) is approximately _ L /min and pulmonary blood flow (perfusion Q) is approximately _ L/min
4L/min (V) 5L/min
The V/Q ratio for the entire lung is _
0.8 (4/5)
V/Q must be matched with the lung at the _ - _ level for gas exchange to occur
alveolar-capillary
Perfusion in the _ portion of the lung have greater amount of blood flow than the _
dependent (bases)
apex
Ventilation is greater in more _ parts of the lung, which are _ portions of the lung
compliant
dependent (bases)
Alveoli in the non-dependent portions of the lung, like the _, is more inflated and _ compliant
apex
less compliant
Difference between ventilation and oxygenation:
ventilation - moving air in and out of lungs, delivers O2 to alveolar space and removes CO2
oxygenation - delivering O2 from the lungs to body’s tissues
When standing, most of the ventilation and perfusion occurs at the _
base / dependent portion / zone 3
Which portion of the lung is more compliant?
dependent portion / base / zone 3
Which portion of the lung is less compliant?
apex, superior portion, “up lung”
Which monitor measures ventilation and which one measures oxygenation?
V = capnography
O2 = pulse ox
Pa =
Pv =
PA =
pulmonary arterial flow = Pa
pulmonary venous flow = Pv
alveolar pressures = PA
In an upright pt, where does most of tidal volume breath distribute to and why?
dependent portion / bases
-perfusion increases from the top - down (apex to base), negative pulmonary pressure is highest at apex of lungs so alveoli are most distended there, dependent alveoli are less distended and more compliant
Lung zones:
Zone 1
alveoli are at a HIGHER resting volume, represents alveolar dead space
PA > Pa > Pv
When PA > Pa = perfusion is impeded
Lung zones:
Zone 2
Variable relationship between vascular and alveolar pressure; intermediate zone
Pa > PA > Pv
Lung zones:
Zone 3
dependent part of lung, alveoli rest at LOWER volumes than zone 1 + 2 so they are more compliant and allow continuous blood flow thru the respiratory cycle
Pa>Pv>PA
An alveolus that undergoes a _ (greater/lesser) degree of volumetric change during a breath is going to be better ventilated. (Q!)
greater
-these are the dependent parts of lungs
Ventilation is greatest at the lung _ due to a _ alveolar compliance
Perfusion is greatest at the lung _ due to _
base, higher
base, gravity
T/F An alveolus that undergoes a greater degree of volumetric change during a breath is going to be better ventilated than an alveoli that undergoes a smaller degree of volumetric chancge during that breath
true
-dependent!!! :)
Most of the Vt is distributed to the _ alveoli
dependent
At end expiration, the alveoli near the _ are the largest and the alveoli near the _ are the smallest
apex = largest
base = smallest
compliance equation
compliance = change in volume / change in pressure
Lung compliance concept that “will be on every test you take for anesthesia board prep” (Q!)
volume difference at end expiration and end inspiration is smallest difference at the apex of the lung and greatest in the base of the lung
additionally, the ventilation is greatest at end expiration from the base and smallest at the apex
The more volume change an alveoli experiences will have better ventilation/perfusion (dependent!)
_ and _ _ affect the distribution of blood flow to the lung.
Gravity
hydrostatic pressure
When standing upright, less blood flows to the _ of the lung and more blood flows to the _
apex
base
There are _ (higher/lower) V/Q ratios towards the apex and _ (higher/lower) ratios towards the base
higher ratio at apex
lower ratio at base
V/Q terminology confusion:
-Higher V/Q ratio at _ and lower at _
-V/Q mismatch is HIGHER at _ and lower at _
-V/Q match is HIGHER at _ and lower at _
V/Q Ratio: Apex > Base
V/Q Mismatch: Base > Apex
V/Q Match: Apex > Base
-don’t confuse these differences on exams
ex) V/Q 4/5 = 0.8
apex: 5/4 = 1.25
Positions and dependent / non-dependent lung regions:
-Sitting
Dependent: base
Non-dependent: apex
Positions and dependent / non dependent lung regions : Supine
D: posterior
ND: anterior
Positions and dependent / non dependent lung regions: L Lateral Decubitus
D: Left lung
ND: right lung
Positions and dependent / non dependent lung regions: R Lateral decubitus
D: Right lung
ND: Left lung
Position effects on V + Q: awake lateral
diaphragm -> cephalad on DEPENDENT SD
More Vt in D lung on inspiration and
Q > in D lung
Gas exchange is still efficient
Position effects on V + Q: anesthetized lateral closed chest, SV
FRC decreases immediately
V is preferentially distributed to the ND lung but gravity dependedn BF preferentially distributes to D lung -> V/Q mismatch
Positions and dependent / non dependent lung regions: Anesthetized, paralyzed, MV
diaphragm no longer contributes to V of lower lung. V shifts to path of least resistance; preferring the ND lung
V/Q mismatch further deteriorates
prolly on test!
Positions and dependent / non dependent lung regions: Anesthetized, open chest
after thorax is opened, lung detaches from chest wall
V prefers ND lung
if MV and open chest, there is no resistance so V goes to nondependent lung -> extreme V/Q mismatch
prolly on test
Positions and dependent / non dependent lung regions: Anesthetized, open chest, OVL
little resistance to V of the ND lung
-gravity promotes Q to the D lung
-when OVL is started and ND lung isn’t ventilated, V is directed to the D lung and remaining Q going to ND lung creates a shunt BUT HPV reduces shunt bu 50% by diverting a lot of blood to D lung
this is how body keeps V/Q ratio matched
-prolly on test
What is HPV and how does it work
hypoxic pulm vasoconstriction
-reflex mechanism that causes pulm arteries to vasoconstrict in response to ALVEOLAR HYPOXIA and shunt blood away from hypoventilated lung tissue to areas of better oxygenation
-OLV - whenever the non-ventilated lung is still perfused, a mismatch occurs
Inhibitors of HPV
MAC > 1 - vasodilates
Mitral Stenosis - increased Pulm vasc pressure
Volume overload - periph vasodilation
Hypovolemia - vasoconstricts and overdistends alveoli
HYPOthermia - increased PVR
Infection - vasodilates
Vasodilators - vasodilates
Metabolic Alkalemia - vasodilates
Vasoconstrictors - increases pulm BF
-want euvolemia, moderate Vt, avoid excessive PEEP, hypocapnia, and alkalosis
Lung CA
-pancoast syndrome
tumor on apex of lungs
-spreads to ribs and vertebrae
-compresses stuff
-hard to intubate potentially
-bad prog
4 Ms of Lung CA
Mass effect (abscess, obstructive PNA, distortions, SVC or pancoast syndrome,
Metabolic effects (LEMS, hyperCa, cushing)
Mets (brain, bone, liver, etc)
Medications (Bleo)
Clinical hallmark of COPD
smoking
PFTs showing _ % improvement post-bronchodilator are good results
> 12%
PFTs purpose before thoracic or lung procedures
predict postop complication risk
The maximum volume of air that the lungs can hold after a maximum inhalation is the:
TLC
~6L
TLC =
TLC = Vt + ERV + IRV + RV
IC (insp capacity) =
IC = IRV + Vt
FRC =
ERV + RV
VC =
IRV + Vt + ERV
The volume of gas expired rapidly and forcefully after one breath is:
FVC ~5L
The volume of gas expired forcefully in 1 sec:
FEV1 ~4L
FEV1/FVC can show:
differences between obstructive or restrictive dz
If both FEV1 and FVC are low and ratio is =/<0.7 and TLC is increased, the dz pattern is:
obstructive
-emphysema
If both FEV1 and FVC are low and ratio is =/>0.7 and TLC is decreased, the dz pattern is:
restrictive
-asthma
Normal FEV1/FVC is _ in 1 sec
0.7 or 70%
A FEV1/FVC of _ is a sign of severe reduced lung function
0.4 or 40%
Describe the obstructive breathing pattern on the F/V loop
Insp volume is large
Ability to exhale is decreased from alveoli retaining air
TLC is increased
Describe the restrictive breathing patter on the F/V loop
unable to deeply inspire from constricted airway/alveoli
unable to exhale large volume because didn’t breathe in much
TLC is decreased
Describe the breathing pattern with tracheal stenosis on the F/V loop
unable to inhale much volume past the obstruction
expiration takes longer from obstruction and unable to release all volume before needing to inhale again
TLC is increased
Pack/year index =
PPD smoked x yrs smoking at that rate
Smoking cess < _ wks doesn’t alter risk for complication
<4wks
<1 month = more secretions actually
If pt is cyanotic, arterial oxyhgb is _ % or less and PaO2 is < _ mmHg, indicating reduced respiratory reserve
<80% OxyHgb and < 50mmHg PaO2
Dx criteria for chronic bronchitis=
recurrent productive cough for 3 months of the year for 2 years straight
What s/s should alert CRNA to possibility of a tumor in the aurway?
blood stained sputum or gross hemoptysis
Which 2 aspects of COPD increase risk for RVH and RV failure?
Lung hyperinflation from airway inflammation increases RAP, decreasing venous return and RV preload
Pulm HTN from COPD increases afterload on RV increasing strain to pump forward into lungs
Risk factors for RVH beyond COPD
acidosis
sepsis
hypoxia
increased amounts of PEEP
EKG s/s of RVH
low voltage QRS
poor R wave prog
enlarged P wave
What happens to lung volumes with anesthesia? (Q!)
errthng drops from decreased muscle tone
Absolute reasons for OLV (Q!)
VATS
Isolating lung
-abscess/hemorrhage/infection
Controlling vent distribution
-bronchopleural fistulas, ULcysts or bullae, major disruption or trauma
UL lavage
Relative reasons for OLV
Surgical exposure
-TAA
-Pneumonectomy
-Esophageal Surgery
Directions for placing DLT
-concave part inserted facing anterior
-pull stylet when just past VC, turn 90 deg L so proximal opening is facing anterior and advance
-inflate tach cuff, listen for BBS
-inflate bronchial cuff, open cap, listen for BS on surgical sd
-clamp bronchial sd, open cap, and listen for BS on other sd
-use fiberoptic to confirm placement when supine and after repositioning
What kind of trauma can occur from DLT placement?
airway
DLT sizes for men: (Q!)
39 or 41 fr
Avg depth of L sd DLT is _ cm
29cm
Inflate the blue/bronchial cuff on a DLT with _of air
2-3mL
T/F the bronchial cuff on a DLT should be left uninflated until lung isolation is needed for the procedure
T
T/F Checking DLT placement with a pediatric fiberoptic is the standard of care
T
Most common problems with DLT are usually _ (Q!)
MALPOSITIONING
If there is a sudden change in ventilation during a case using a DLT, what should be checked first?
if there is mispositioning of the DLT
Managing OLV
Start w 100% FiO2 then wean to keep HPV
Vt of 4-6mL/kg + PEEP 5 (or cut Vt in 1/2), RR to keep PaCO2 35-40
Recheck DLT with fiberoptic after placement + repositioning
Managing OLV (Q!)
-high peak pressures (>40cmH2O)
make sure DLT isn’t malpositioned!
Managing OLV (Q!)
-hypoxic (1st resort, 2nd resort, last resort)
1st resort: CPAP 5cm to non dependent lung
2nd resort: PEEP 5-10 to lung being ventilated, recruitment maneuvers
Last resort: tell surgeon 2 lung ventilation is needed and may need it intermittently
Single most effective maneuver to increase PaO2 during OLV is:
CPAP to nondependent lung (Barash)
-per Lori tweaking FiO2, Vt, PEEP usually works fine tho
HPV shunting during OLV is effective in decreasing the CO to the nonventilated lung by _%
50%
HPV begins within seconds and is fully established in _ min
15 min
Mediastinoscopy (Q!)
-scope placement
via suprasternal notch incision
-scope is ANTERIOR to trachea + POSTERIOR to the aortic arch and R innominate artery
-L RLN is at risk, same with tons of vessels (innominate artery)
Mediastinoscopy is helpful in staging lung CA but can have obstructions to airway/ procedure. What can we do for induction/maintenance if this is the case?
LA + awake fiberoptic for induction
-maintain spont vent
-may need sitting up position
-if mass compressing SVC may need fem line
-airway may be compressed if supine, consider side lying or prone if possible
Mediastinoscopy
-CI
previous mediastinoscopy + serious scarring
relative: SVC obstruction, tracheal deviation, TAA
Mediastinoscopy
-most common complication
hemorrhage
-R innominate
Mediastinoscopy (Q!)
-where to place A line/BP cuff and pulse ox
A line/BP cuff and/or SpO2 probe on R finger to monitor for compression of R subclavian artery
Mediastinoscopy
-anesthesia goals
regular tube
position: head is turned 90 deg
short case - avoid excessive paralytic/reverse well
avoid bucking on emergence
meds: LTA kit, lidocaine, precedex, narcs
A line/pulseox on R finger to watch for R subclav compression
Thoracotomy
-regional option
thoracic epidural T6-T8
paravertebral blocks
very painful
Thoracotomy
-anesthesia goals
pain control (chest tube placed after)
T+S expect high blood loss up to 1L
check DLT after repositioning laterally with fiberoptic
check ABG 15 after OLV is started
unclamp and reinflate lung afterwards manually ventilating up to 30cm pressure or whatever surgeon asks for, watch for lung inflation on screen
emerge awake, sitting up, avoid coughing (precedex)
Video-assisted Thoracoscopic Surgery (VATS)
-supplies needed
2 diff sizes of DLT
backup ETT + blade
clamps
Glide/Fiberoptic (purple/turquoise at RO)
CPAP capabilities
long suction caths
A line ready, 2 big IVs
tape for EKG leads
temp control + positioning crap
DLT
-unable to place
Try smaller size
Try gently twisting thru VC with DL
Place single lumen tube, ventilate, use exchange cath/bougie, remove ETT, and place DLT that way
- do not shove this thing in, don’t let techs take away fiberoptic until case is over
DLT
-unable to deflate nondependent lung
Check placement with fiberoptic, is bronch cuff overinflated?
apply mild/gentle suction to noninflated port and suction air out of “up” lung
-this can take up to 10 mins
Extubation criteria for thoracic cases
-VATS
Awake
Full reversal
no coughing
Extubation criteria for thoracic cases
-Pneumonectomy
Awake
High fowlers
Extubation criteria for thoracic cases
-Esophagectomy
Awake
maybe in ICU
Rigid Bronch
-indications
Remove larger foreign bodies
Deeper biopsy
Washout
Tumor staging
Bleeding
Dilation of tracheal or bronchial strictures
Inserting stents
Tumor ablation/ tracheobronchial laser therapy
Rigid bronch (Q!)
-meds
TIVA is best
LTA kit
Lidocaine + Propofol induction
Prop/Precedex gtt
Ketamine pushes/ Remi gtt
Esmolol before inserting scope (0.5mg/kg)
Decadron ~12mg
Rigid Bronch (Q!)
-anesthesia method
-case tips
TIVA
LMA 1st then manual vent thru rigid bronch sideport
OPA + bag if desatting
mouth guard
extention tubing
EXPECT HTN + tachy - stimulating then not at all
Rigid bronch
-complications
VC injury
pneumo
teeth damaged
desatting
HTN/ tachy
airway trauma
gum tears
hemorrhage
Flexible bronch
-indications
biopsy
removing small foregin object
tumor staging
washout
diagnostics
Flexible bronch
-which airway device is used
larger (~1-1.5 size up) ETT
T/F A pneumonectomy can either be achieved via VATS or thoracotomy
true
Pneumonectomy
-suppliesq
L sd DLT + backups + fiberoptic/glide
Thoracic epidural (T6-T8)
T+C - 2 units ready (give albumin/blood instead of fluids)
2 big IVs
A line ready
ABG after 15 mins OLV
foley, temp control, positioning crap, tape
Pneumonectomy
-meds
Albumin/blood
Phenyl gtt
possibly: Dig, Milrinone, NTG, hydral
Pneumonectomy
-anesthesia goals
KEEP PT DRY (surg will assess RV function/ PVR when clamping PA, avoid tweaking things unless needed)
Check ABG after 15 min OLV
Give albumin or blood if needed
Surg will ask for 20-30cm PIP for valsalva to check for leaks after sutures
awake extubation
Pneumonectomy
-PPS
post-pneumonectomy space
-chest tube not always places, PPS shrinks over time as body adjusts around it and replaces space with fluid, mediastinum shifts towards PPS
Pneumonectomy (Q!)
-main complication
RV can dilate and function decreases from increased RV afterload from increased PAP and PVR
cut off PA on dz lung so all BF going to the remaining PA
others: resp fail, pulm edema, dysrhtyhmias, cardiac herniation
Esophagectomy (Q!)
-induction
RSI
-esophagus can be full
Esophagectomy
-supplies
ETT + DLT + glide/fiberoptic
Thoracic epidural maybe
A line
2 large IV
2 units PRBC
temp control
DO NOT PLACE OGT/NGT UNLESS SURG ASKS
Esophagectomy
-fluid status
pt will be extra dry
-emaciated from bowel prep and tumor impeding PO intake
-higher Hgb = pt is drier, follow UO too
ask surgeon, use ALBUMIN if fluids needed or phenylephrine; surg doesn’t want pt too wet so they can suture
Esophagectomy (Q!)
-anesthesia goals
keep pt on dry side
if HOTN - phenylephrine, albumin -ask surg
check Hgb and monitor UO for fluid status (Hgb increasing = dry)
TRANSHIATAL IS HARDEST: Surg pulling stomach thru neck incision compresses heart and tanks BP (albumin+pressors)
tape very well, lots of manipulation
long case, may need sections of colon, carefully sparing vagus nerve!
have blood ready
extubate in ICU, awake
pts will have G tube after these
Esophagectomy (Q!)
-most common complications
1. RESPIRATORY
2. Cardiac
3. Wound Infection
4. Anastomotic leak
Esophagectomy (Q!)
-why is transhiatal approach harder
very hypovolemic
bowel prep
secure ETT VERY WELL lots of movement
unable to reach airway after induction
neck incision on L sd
pulling stomach up thru neck incision compresses heart and tanks BP
Esophageal Rupture (Q!)
-clinical presentation
s/s:
neck/back pain
cyanotic
hydrothorax
emphysema
pneumomediastinum
septic
Esophageal Rupture (Q!)
-causes
vomiting violently
straining with weights
child birth pushing
severe alcoholism
crush injury/trauma/ MVA
Esophageal Rupture (Q!)
-surgical case required
-how would you intubate?
Thoracotomy + RSI or awake intubation
Tracheal Resection
-supplies
2 large IVs
A line
Cordis + CVP
Swan if bypass may be needed
smaller ETT
Tracheal Resection
-meds
corticosteroids
diuretics
racemic epi
avoid fluids!
Thymectomy
-MG tx
only tx that removes CAUSE of MG
Thymectomy
-MG drugs
continue pyridostigmine thru DOS or give Neostigmine if pt missed dose
-have blood in room + give stress dose steroid
Thymectomy (Q!)
-MG + NDMR?
They will need LESS
-they have less AChR that are functional so they’re more sensitive to MR
-also can be sensitive to Neostigmine reversal and have weakness from cholinergic crisis
Thymectomy
-postop MV considerations (4)
-sternotomy performed?
-MG dz duration > 6yr?
-Chronic resp condition?
-Pyridostigmine dose > 750mg/day?
Pulm Decortication (Q!)
-clinical presentation
pt sick AF + pleura thick AF (need to be scraped off)
-empyema, clotted hemothorax, TB, mesothelioma, lung CA, staph infection, extreme COPD
-pt very fatigued, tachypneic, already tubed, acidotic, low PaO2, hard to ventilate (stiff/ restrictive dz)
Risk factors for ALI from thoracic cases:
Preop: ETOH, previous pneumonectomy, poor PFT, hypervolemic
Intraop: high ventilatory pressures, excessive IVF
If DLT is on L sd and TRACHEAL lumen clamped, the _ lung will inflate (Q!)
Left
If DLT is too far into the L sd, the _ lung will inflate (Q!)
Left
If DLT is on the L sd and BRONCHIAL lumen is clamped, the _ lung will inflate (Q!)
Right
Awake Lateral Position OLV (Q!)
diaphragm displaced cephalad and on dependent sd
Insp: diaphragm causes Vt to go in dependent lung
Perfusion is better in dependent lung
V/Q stays efficient
VC = (Q!)
VC = Vt + ERV + IRV
TLC = (Q!)
TLC = Vt + ERV + IRV + RV
IC =
IC = IRV + Vt
FRC =
FRC = ERV + RV
