Lung Protective Ventilation

Question 1

Ptp=

Answer 1

Palv-Ppl
maintain (+) Ptp
increasingly (+)Ppl means increasingly (-) Ptp and favors atelectasis

Question 2

maintaining a positive trans pulmonary pressure during surgery is dependent n maintaining

Answer 2

alveolar pressure

Question 3

anesthesia and surgical effects on lungs

Answer 3

loss of muscle tone, cephalic displacement of abdominal contents, alveolar compression
elevated intraabdominal pressure, increased BMI, pneumoperitoneum, trendelenburg

Question 4

transition from upright to supine decreases FRC by

Answer 4

.8-1L

Question 5

induction agents reduce FRC by

Answer 5

.4-.5L

Question 6

total reduction of FRC from supine and induction

Answer 6

1.2-1.5L

if FRC is impinging on closing capacity, atelectasis occurs

Question 7

factors that contribute to alveolar collapse

Answer 7

position
induction
FiO2 (increased FiO2 is faster resorption behind closed airways)
maintenance (compliance)
emergence (high FiO2 promotes postop atelectasis, absence of CPAP means continued lung collapse)

Question 8

ventilation induced Lung injury (VILI)

Answer 8

ventilator does not cause injury but the settings of the vent does (increased TV or pressures)

Question 9

ventilation associated lung injury (VALI)

4 examples

Answer 9

specific to OR setting
volutrauma (damaged endothelium, decreased surfactant, increased cap leak)
barotrauma (damage from postitive pressure)
atelectrauma (repeated collapse and reinflatio of alveoli)
biotrauma (all of these 3 lead to this, inflammatory mediator release. bad cycle)

Question 10

LPV initial maintenance settings

Answer 10

Low TV 6-8ml/kg IBW
minimize FiO2 <30%
individualized PEEP: 30% of BMI
alveolar recruiemtn maneuvers
I:E ratio 1:1.5

Question 11

LPV emergence settings

Answer 11

FiO2 <80%
positive pressure ventilation, must be greater than closing pressure
elevated HOB to shift diaphragm caudad

Question 12

Induction Strategies

Answer 12

goal is to attenuate anesthesia related changes
initial FiO2 100%
elevate HOB >30%
tightly sealed face mask- apply CPAP. use APL valve or CPAP mode on vent
OPA or NPA PRN

Question 13

goals of maintenance anesthesia

Answer 13

restore lung volume with alveolar recruitment maneuver (ARM)
maintain lung volume and minimize atelectasis formation (individualize PEEP)
maximize lung compliance (use lowest possible drivingp pressure)

Question 14

driving pressure=

Answer 14

Pplat-PEEP

PC-VG and PCV won’t have Pplat so use Pip

Question 15

compliance =

Answer 15

TV/driving pressure

Question 16

maintain SpO2 at

Answer 16

> or equal to 94%

Question 17

purpose of maintenance FiO2 and SpO2

Answer 17

reduce resorption atelectasis, use SpO2:FiO2 curve as monitor to assess if we are maintaining open lung ventilation. SpO2:FiO2 ratio shows you if you’re exceeding critical opening pressure

Question 18

at 21% if sats are less than 97%

Answer 18

we know greater than 10% intrapulmonary shunt is occurring

Question 19

alveolar recruitment maneuvers

Answer 19

bag squeezing technique

ARRM through ventilator is ideal aka vital capacity maneuver on vent in CPAP mode

Question 20

minimum recruitment pressure required for a BMI <30

Answer 20

40cmH2O

Question 21

minimum recruitment pressure required for a BMI 30-40

Answer 21

40-50cmH2O

Question 22

minimum recruitment pressure required for a BMI 40-50

Answer 22

50-55cmH2O

Question 23

minimum recruitment pressure required for a BMI > or equal to 50

Answer 23

50-60cmH2O

Question 24

initial setting of PEEP and purpose

Answer 24

BMI x .3 (to a max starting PEEP of 15)
purpose is to maintain end expiratory lung volume, reduce atelectasis formation, must be proceeded by ARM so you dont induce barotrauma

Question 25

I:E ratio for a BMI <45

Answer 25

1:1.5

Question 26

I:E ratio for a BMI >45

Answer 26

1:1 because they have increased pressure on chest and have faster expiration anyway

Question 27

I:E ratio purpose

Answer 27

reduce airway pressures, increase homogenous ventilation

Question 28

emergence goals

Answer 28

maintain open lung throughout emergence

minimize anesthesia induced changes during postop period

Question 29

emergence FiO2 and purpose

Answer 29

maintain FiO2 less than or equal to 80 throughout

purpose is to reduce atelectasis formation

Question 30

positive pressures ventilation during emergence

Answer 30

maintain CPAP and PEEP throughout

purpose is to prevent atelectasis formation and maintain open lung state

Question 31

HOB elevation purpose

Answer 31

decrease chest wall compression and increase lung compliance

Question 32

concerns for using postop excessive O2 use

Answer 32

activation of ROS
periphrealy/coronary vasoconstriction
decreased CO
absorption atelectasis

Question 33

pressure volume loop

Answer 33

assessment of driving pressure or pressure required to deliver set volume
want to maximize volume delivered at lowest pressure. widening loop is bad and means downtrending compliance

Question 34

flow volume loop

Answer 34

representation of expiratory flow. acute angle represents expiratory flow limitation