Gruneisen, Nur 635: Thoracic Anesthesia; Hpv

Front 1

________ ________ ______ is known as a compensatory mechanism to divert blood from the deflated lung to areas of better ventilation and oxygenation.

Back 1

Hypoxic Pulmonary Vasoconstriction

Front 2

A shunt is known as ________ without ________.

Back 2

perfusion, ventilation

Front 3

HPV is a intrapulmonary fedback mechanism to improve _______ _______ and _________ _________.

Back 3

gas exchange, arterial oxygenation

Front 4

Decreased O2 in systemic circulation leads to ________.

Back 4

vasodilation

Front 5

Decreased O2 in pulmonary circulation leads to ________.

Back 5

vasoconstriction

Front 6

The purpose of HPV is to _________ shunt flow.

Back 6

decrease

Front 7

Response to systemic hypoxia mediated by stimulation of _________ and ________ chemoreceptors in CNS.

Back 7

peripheral, central

Front 8

Response to HPV is localized.
True or False

Back 8

True

Front 9

HPV onset and resolution are very fast following changes in tissue ____.

Back 9

PaO2

Front 10

HPV is triggered by arterial hypoxemia.
True or False

Back 10

False, it is triggered by alveolar hypoxia.

Front 11

In general, HPV causes vasoconstriction in all but very proximal ________ _______.

Back 11

pulmonary arteries

Front 12

HPV may be inhibited by(anesthetic agents/meds):

Back 12

NTG, nipride, volatile anesthetics > 1.5 MAC (vasodilators), Ca++ channel blockers.

Front 13

Volatile anesthetics inhibit HPV in a dose related manner.
True or False

Back 13

True

Front 14

HPV is increased by:

Back 14

hypercarbia and hyperthermia

Front 15

The greatest stimulus for HPV is:

Back 15

decreased O2 tension in alveolar gas.

Front 16

The cellular mechanism for HPV involves a redox-based oxygen sensor in _________ ________ cell of the pulmonary arteries.

Back 16

smooth muscle

Front 17

Activated oxygen species (AOS) production are reduced by hypoxemia, therefore, these AOS cannot act as 2nd messengers and this leads to inhibition of voltage-dependent _______ ________.

Back 17

Potassium channels.

Front 18

Inhibition of voltage-gated potassium channels leads to influx of extracellular _________, which causes _________.

Back 18

Calcium, vasoconstriction.

Front 19

HPV during OLV causes a decrease in the CO to the nonventilated lung by ______ percentage.

Back 19

20-25%

Front 20

HPV can decrease the shunt fraction during OLV by ____%

Back 20

50%

Front 21

What is the optimal amount of hypoxic lung during OLV in order for HPV to be most effective?

Back 21

between 20-80%

Front 22

If the amount of hypoxic lung is more than 80%, HPV increases PVR and the amount of well-perfused lung is not sufficient to accept shunt flow to maintain arterial oxygenation. This can lead to _____ ______ ________.

Back 22

right ventricular failure

Front 23

What conditions can override HPV?

Back 23

hypervolemia and high cardiac output; shunt fraction <20% or > 80%; hypocapnia, acidosis, volatile agents > 1.5 MAC, vasoactive medications; hypovolemia; or hypothermia; COPD.

Front 24

Fluid and ventilator management of OLV should include:

Back 24

normal fluid volume, moderate TV (6-7 ml/kg); PIP < 25; adjust rate to maintain PaCO2 at 35 +/- 3; and excessive peep should be avoided.

Front 25

Which volatile agent should be avoided with HPV due to its tendency to increase PVR?

Back 25

Nitrous oxide; use 100% O2 instead.

Front 26

In atelectatic lung areas, what is the greatest stimulus for HPV?

Back 26

PvO2

Front 27

Anything that increases PAP decreases efficiency of HPV.
True or False

Back 27

True

Front 28

Which antihypertensive drug has no effect of HPV?

Back 28

Hydralazine

Front 29

How is placement of the OLV tube checked?

Back 29

fiber optic visualization

Front 30

How can hypoxia during OLV be treated?

Back 30

CPAP to nondependent lung, PEP to dependent lung, intermittent two-lung ventilation