M7 MV

Question 1

Factors that impact pulmonary ventilation

Answer 1

lung compliance
surface tension of alveoli
airway resistance

Question 2

boyles law pressure and volume and how this relates to ventilation

Answer 2

the pressure of a gas in a closed container is inversely proportional to the volume of a container

if hte size of the container is decreased the pressure inside increases, and the opposite is true

when the diaphragm flatterns and contracts it increases the size of the thoracic cavity, decreasing the size of the abdominal cavity, this causes a change in pressure gradient within the thoracic cavity and draws air into the lungs

Question 3

normal vt

Answer 3

approx 500mls

Question 4

residual volume
defintion
values for men and women

Answer 4

volume of air that remainds in the alveoli after forced expiration
w = 1,100mls
m= 1,200mls

Question 5

expiratory reserve volume
define
men and women values

Answer 5

volume of air that can be forcefully expelled from the lungs after normal expiration
w= 700mls
m= 1,200ms

Question 6

inspiratory reserve volume
define
men and women values

Answer 6

additonal volume of air you can inspire following a normal inspiration
f= 1,900mls
m= 3,100mls

Question 7

inspiratory capacity
define
normal values

Answer 7

volume of air that can be inspired normally, in addition to any air that can be inspired forcefully
= VT + IRV
f = 2,400mls
m= 2,300mls

Question 8

FRC
define
normal values

Answer 8

volume of air left in the lungs after normal expiration
f= 1,800mls
m= 2,300mla

Question 9

vital capacity
define
normal values

Answer 9

max amount of air that can be exhaled from the lungs after max inspiration
is a measure of lung function
= IRV + ERV + VT
F= 3,100mls
M= 4,800mls

Question 10

TLC
define
normal values

Answer 10

volume of air that can be contained within the lungs after maximal inspiration
= VC + residual volume
f = 4,200mls
m= 6,000mls

Question 11

define anataomical deadspace
what structures are involved

Answer 11

refers to the conducting airways of the respiratory system that are not directly involved in gas exchange
= nose, pharynx, larynx, trachea, bronchi, bronchioles and terminal bronchioles
approx 1/3 of every breath occupies the anatomic dead space and for that reason not all of the MV can be used in gas exchange

Question 12

what is the 60/60 rule

Answer 12

as our pco2 increases >60 = type 2 failure
as our pO2 decreases <60 = type 1 failure
type 3 is a mixture of both

Question 13

invasive ventilation is associated with (side effects)

Answer 13

raised ICP
reduced CVP
risk of hospital acquired pneumonia
loss of respiratory muscle strength
increased abdominal pressure
general ICU problems
activation of RAS = fluid retention
abnormal respiratory process

Question 14

What setting is for titrating ventilation on MV

Answer 14

respiratory rate

Question 15

what settings are for titrating oxygenation and how to implement it

Answer 15

PEEP and FiO2
Once FiO2 is greater than 50%, any continuing hypoxaemia is due to physiological shunting . the solution is to increase the mean arterial pressure through PEEP (alveolar recruitment)

Question 16

How do you check for alveolar safety on the MV
what is the normal peak pressure
and how do you correct it

Answer 16

check your plateau pressure every 30-60/690

press inspiratory hold button at the end of the breath

anything around 20-30cmH2O is normal, anything greater than 30 you need to be asking why

solution: decrease the VT by 1ml/kg until pressure <30 is achieved

Question 17

Peak pressure vs Plateau pressure

Answer 17

Peak Pressure represents the pressure generated by the ventilator to overcome both airway resistance and alveolar resistance. (inspiration and air being pushed into the lungs)

Plateau Pressure measures the pressure on the alveoli/ the pressure that is left over in the lung after the tidal volume has been delivered. (static pressure at end of inspiration)

Question 18

Obstructive patients
Managing high peak pressures and ensuring adequate ventilation… how?

Answer 18

Will naturally have high pressure due to bronchospasm

if the peak pressure alarm is set too low, the vent may terminate the breath prematurely and the patient will recieve little to no alveolar ventilation

to prevent this- increase peak pressure alarm to ensure full tidal volume breath is delivered

the peak pressure will be high BUT the plateau pressure should remain well below the 30cmh20 (as long as the patient is able to fully exhale)