Lung Protection Ventilation

Question 1

maintaining positive transpulmonary pressure during surgery is dependent on

Answer 1

maintaining alveolar pressure

Question 2

anesthesia and surgical effects on the lungs

Answer 2

loss of muscle tone- obstruction, abdominal contents cephalad displacement, alveolar compression
Increase intraabdominal pressure- pneumoperitoneum, trendelenburg positioning, increased BMI

Question 3

induction of anesthesia causes a ____ in FRC

Answer 3

reduction

Question 4

transition from upright to supine decreases FRC by

Answer 4

0.8-1L

Question 5

induction agents reduce FRC by

Answer 5

0.4-0.5L

Question 6

total reduction in FRC

Answer 6

1.2-1.5L , close to residual volume

Question 7

factors that contribute to alveolar collapse

Answer 7

position (increased closing pressure), induction (loss of muscle tone), FiO2 (resorption behind closed airways, increased FiO2), maintenance (progressive airway closure with decreasing compliance), emergence (high FiO2, absence of CPAP)

Question 8

ventilation induced lung injury

Answer 8

ventilator does not cause injury but the settings of the ventilator

Question 9

ventilation associated lung injury

Answer 9

specific to OR setting

Question 10

volutrauma

Answer 10

damaged endothelium, decreased surfactant, increased capillary leak

Question 11

barotrauma

Answer 11

damage from positive pressure effects

Question 12

atelectrauma

Answer 12

damage from repeated collapse and re-inflation

Question 13

biotrauma

Answer 13

damage from release of inflammatory mediators

Question 14

conventional lung ventilation

Answer 14

not individualized, Vt: 10-15mL/kg TBW, PEEP: 0-5 cmH20, I:E: no greater than 1:2, FiO2: provider preference

Question 15

LPV Initial maintenance settings

Answer 15

low Vt: 6-8mL/kg IBW, minimize FiO2: <30%, individualized PEEP: 30% of BMI, alveolar recruitment maneuvers, I:E: 1:1.5

Question 16

LPV emergence settings

Answer 16

FiO2 <80%, positive pressure ventilation, elevate HOB

Question 17

induction strategies

Answer 17

FiO2 initially 100% , elevate HOB >30, tight mask seal, apply CPAP, OPA/NPA prn

Question 18

goals of maintenance phase

Answer 18

restore lung volume, recruitment maneuver, maintain lung volume and minimize atelectasis formation, maximize lung compliance, lowest possible driving pressure

Question 19

tidal volume

Answer 19

initial setting: 6-8 mL/kg IBW

Question 20

maintenance FiO2

Answer 20

initial: 30%, maintain spo2 > 94%
purpose: reduce resorption atelectasis, maintain open lung ventilation using spo2:FiO2 curve

Question 21

at 21%, if saturation less than 97% we know

Answer 21

greater than 10% intrapulmonary shunting is occuring

Question 22

alveolar recruitment maneuvers

Answer 22

bag squeeze, vital capacity maneuver

Question 23

BMI <30 minimum recruitment pressure required

Answer 23

40 cm H2O

Question 24

BMI 30-40 minimum recruitment pressure required

Answer 24

40-50 cmH2O

Question 25

BMI 40-50 minimum recruitment pressure required

Answer 25

50-55 cmH2O

Question 26

BMI >50 minimum recruitment pressure required

Answer 26

50-60 cmH2O

Question 27

PEEP

Answer 27

initial setting: BMI x 0.3 | purpose: maintain end expiratory lung volume, reduce atelectasis formation

Question 28

I:E ratio

Answer 28

initial setting: BMI <45: 1:1.5 BMI >45: 1:1 purpose: reduce airway pressures, increase homogenous ventilation

Question 29

goals during emergence

Answer 29

maintain open lung throughout emergence, minimize anesthesia induced changes during postop period

Question 30

emergence FiO2

Answer 30

maintain <80% | purpose: reduce atelectasis formation

Question 31

positive pressure ventilation

Answer 31

maintain CPAP and PEEP throughout | purpose: prevent atelectasis formation, maintain open lung state

Question 32

HOB elevation

Answer 32

>30 degrees | purpose: decrease chest wall compression, increase lung compliance

Question 33

concerns with excessive O2

Answer 33

activation of ROS, peripheral/coronary vasoconstriction, decreased CO, absorption atelectasis

Question 34

what does down trending compliance represent?

Answer 34

atelectasis

Question 35

pressure volume loop

Answer 35

assessment of driving pressure (pressure required to deliver set volume) want to maximize volume delivered at lowest pressure

Question 36

flow volume loop

Answer 36

represents expiratory flow | acute angle represents expiratory flow limitation