one lung vent, MH

Question 1

one lung ventilation is indicated for

Answer 1

thoracic surgery, VATS, trauma to chest, any approach passing through the chest (mediastinm, esophagus), or need to isolate a single lung (bleeding, infection, bronchopleural fistula)

Question 2

one lung vent is most often accompanied by

Answer 2

pneumo

Question 3

most used position for thoracic surgery

Answer 3

lateral ducubitus

Question 4

dependent lung =

Answer 4

lower lung

Question 5

non-dependent lung =

Answer 5

upper lung

Question 6

axillary roll is placed on

Answer 6

upper chest wall (not in the axilla)

Question 7

in the awake and lateral position the ____ lung is better perfused and ventilated

Answer 7

dependent

Question 8

with induction of anesthesia, with a decrease in FRC, the ____ lung ventilates more

Answer 8

upper

Question 9

why does positive pressure vent favor upper lung

Answer 9

it is more compliant

Question 10

muscle paralysis favors vent of the ___ lung. why?

Answer 10

upper. due to abd contents pushing up more on the dependent hemidiaphragm

Question 11

rigid bean bag hinders movement of dependent hemidiaphragm and favors ventilation of ___ lung

Answer 11

upper

Question 12

open ptx of upper lung increases ___,favoring vent of ____

Answer 12

compliance, upper lung

Question 13

the lower lung is ___ compliant in lateral decubitus

Answer 13

less

Question 14

zone 1 upright

Answer 14

A a V

Question 15

zone 2 upright

Answer 15

a A V

Question 16

zone 3 upright

Answer 16

a V A

Question 17

open pneumo causes a ____ shunt

Answer 17

large R to L intrapulmonary shunt (20-30%)

Question 18

blood flow to the non ventilated = nondependent = upper lung is ___ by hypoxic pulm vasoconstriction

Answer 18

decreased

Question 19

HPV ___ the r to l shunt

Answer 19

improves

Question 20

surgical compression of the upper lung can __ blood flow, ____ the shunt

Answer 20

decrease, improves

Question 21

3 main factors that inhibit HPV

Answer 21

hypocapnia, vasodilators, inhalation agents

Question 22

factors that decrease blood flow to dependent lung

Answer 22

high mean airway pressures in ventilated lung from PEEP, hyperventilation or increased PIP, low FIO2, vasoconstrictors, intrinstic peep

Question 23

CO2 elimination is usually not affected by one lung ventilation provided: (2 points)

Answer 23

minute ventilation is unchanged and preexisting CO2 retention was not present pre-op (COPD)

Question 24

tidal volumes are kept roughly the same as two lung vent, around ___

Answer 24

10cc/kg. (may adjust due to changes in PIP, RR, altered to maintain normocapnia

Question 25

ventilation can be stopped for short periods as long as

Answer 25

O2 is supplied more than consumption (250-300ml/min)

Question 26

**during apnea PCO2 increases ___ mm for the first minute and then __ mm for each additional minute

Answer 26

5, 3

Question 27

progressive resp acidosis limits apnea oxygenation technique for ___ min

Answer 27

10-20

Question 28

hypoxia during 1 lung vent - want FIO2 of

Answer 28

.8-1

Question 29

hypoxia during 1 lung vent - tidal volume

Answer 29

want 10cc/kg

Question 30

hypoxia during 1 lung vent-adjust RR to keep PaCO2 at

Answer 30

40

Question 31

hypoxia during 1 lung vent - add ___ CPAP to ___ lung

Answer 31

5, nondependent

Question 32

which double lumen tube is most commonly used

Answer 32

left

Question 33

complications of double lumen tubes

Answer 33

traumatic laryngitis, hypoxemia due to malpositioned tube, bronchial trauma from over inflation of cuff, inadvertent suturing of tube

Question 34

what is MH triggered by

Answer 34

inhaled agents (not N20) and succs

Question 35

which receptor is MH

Answer 35

ryanodine

Question 36

first & most sensitive sign of MH

Answer 36

unexplained tachycardia

Question 37

most specific sign

Answer 37

increasing ETCO2, hypercapnia, 2-3x

Question 38

other signs of MH

Answer 38

decreased sat, muscle rigidity, dysrhythmias, tachypnea, cyanosis, sweating, unstable BP, mottling, trismus after succs, darkening of blood in surgical field, decreased mixed venous sat, cola colored urine, heating and exhaustion CO2 absorber, hyperthermia

Question 39

labs of MH

Answer 39

increased K, ca, phos, CK. myogloinuria, hypoxemia

Question 40

MH acid/base

Answer 40

initial metabolic acidosis then a combined metabolic and resp acidosis

Question 41

genetic link of MH

Answer 41

familial autosomal dominant transmission with variable penetrance, on chromosome 19

Question 42

treatment of MH o2

Answer 42

100% at high flows

Question 43

drug/ dosing MH

Answer 43

dantrolene 2.5mg/kg asap then q5min until symptoms controlled or up to 10mg/kg total. must be mixed in sterile water.

Question 44

what do you give for acid/base imbalance in MH

Answer 44

1-2meq/kg then check ABG

Question 45

cooling measures for MH

Answer 45

iced IV NS 15cc/kg every 10min x3. cold body cavity lavage, cooling blanket, ice bags

Question 46

treat hyperkalemia with

Answer 46

bicarb or dextrose 25-50g and regular insulin 10-20 units IV

Question 47

treat persistent ventricular arrhythmias with

Answer 47

procainaminde 200mg IV

Question 48

want urine output to be

Answer 48

>2cc/kg/hr

Question 49

lasix dose

Answer 49

.5-1mg/kb

Question 50

mannitol dose

Answer 50

1g/kg

Question 51

how long should you continue dantrolene

Answer 51

1mg/kg for 6-72h to prevent a recurrence

Question 52

what drug should you not give with dantrolene

Answer 52

calcium channel blockers d/t life threatening hyperkalemia and myocardial depression

Question 53

how does dantrolene work

Answer 53

inhibits ca release from the sarcoplasmic reticulum

Question 54

how does dantrolene work intracellular

Answer 54

dissociation of excitation-contraction coupling

Question 55

late complications of MH

Answer 55

renal failure, coagulopathies, pulm edema, cerebral edema, hepatic failure, left heart failure, DIC, skeletal muscle swelling,rhabdo,death

Question 56

use ketamine and pancuronium with caution because

Answer 56

the tachycardia may mask early MH

Question 57

is propofol benzos barbs narcs LA's n2o, etomidate, ketamine, non-depolarizing agents safe during MH?

Answer 57

yes

Question 58

*gold standard pre-op test ofMH

Answer 58

muscle biopsy with halothane-caffeine contracture test -78% specific and 97% sensitive

Question 59

what syndrome is prom to MH

Answer 59

king-denborough syndrome

Question 60

does a prior uneventful anesthetic rule out MH

Answer 60

no

Question 61

Boys < 9 yrs old who experience sudden cardiac arrest after succinylcholine in the absence of hypoxia should be treated for

Answer 61

acute hyperkalemia

Question 62

symptoms of MH usually occur after how long from exposure

Answer 62

one hour