Ventilation Flashcards

Question

Total lung capacity

Answer 1

IRV+ TV+ ERV+ RV

Answer 2

``` Body size Sex (Males= larger) Disease (pulmonary, neurological) Age Fitness (Innate (more signficant), training) ```

Answer 3

Anatomical dead space 16 generations (bifocations) No gas exchange Typicaly 150 mL in adults at FRC ``` Alveolar dead space Alveoli without blood supply No gas exchange 0 mL in adults Called alveolar dead space ``` Tracheostomy= decreased dead space Anaesthetic circuit= increased dead space

Answer 4

``` Resistance= (8ƞl)/ 𝜋𝑟⁴ ƞ= Viscosity of inspired gas l= length of airway r= radius of airway At higher pressures, can't use a snorkel ```

Answer 5

P(gas) is proportional to 1/ V(gas) | Increase pressure= decrease volume in lungs

Answer 6

1. At start, functional residual capacity in lungs 2. Inspiratory muscles contract= pulls lung tissue apart 3. Creates negative pressure= lower alveolar pressure 4. Creates pressure gradient= generates flow until pressures balance out (at 0cm of water) Ambient pressure= 0cm of water 5. Removal of inspiratory effort= lungs recoil+ compress air= pressure becomes more positive 6. Lower ambient pressure= creates pressure gradient= generates flow from lungs to outside

Answer 7

Chest wall= tendency to spring outwards Lung= tendency to recoil inwards At end-tidal expiration (functional residual capacity) Inspiration= inspiratory muscle effort+ chest recoil> lung recoil Expiration= chest recoil< lung recoil+ expiratory muscle effort

Answer 8

Ribcage+ lung tissue= anatomically linked by pleural space Lungs surrounded by visceral pleural membrane Inner surface covered by parietal pleural membrane In between= pleural cavity (gap between pleural membranes)= FIXED volume, contains protein-rich pleural fluid Skeletal muscle, skeleton, parietal pleura, visceral pleura, lung

Answer 9

Intrapleural vessel bleeding inside lung= compresses lung= less space to expand and fill with air= harder to breathe

Answer 10

Perforated lung/ chest wall: allows air from outside/ inside lung/ blood into the space because the space is a partial vacuum= impairs lung function (like a smaller lung in the same chest cavity)

Answer 11

Negative pressure breathing: P(alv)< P(atm) (P(alv) is reduced), normal Positive pressure breathing: P(atm) > P(alv) (P(atm) is increased), mechanical ventilation, CPR

Answer 12

At rest: Alveolar pressure P(alv)= 0cmH20 Atmospheric pressure P(atm) (unless CPR/ ventilator)= 0cmH20 Intrapleural pressure P(pl)= typically -5cmH20 at rest, under negative pressure because of chest recoiling outwards and the lung recoiling inwards which creates tension. Transpulmonary pressure P(TP)= P(alv)- P(pl) Transthoracic pressure P(TT)= P(pl)- P(atm) Transrespiratory pressure P(RS)= P(alv)- P(atm), dictates air flow: positive= air flows out, negative= air flows in, 0=rest

Answer 13

Diaphragm= pulling force in one direction (syringe) | Respiratory muscles= Upwards+ outwards swinging force (bucket handle)

Answer 14

0 pressure, 3L volume Intact lung= sigmoid shaped: middle of volumes= amount volume that changes per unit pressure= more signficant that at extremes, because less effort to change things e.g. deep breath at 95%lung capacity= harder to breath in Intact lung= product of independent chest wall+ indepedent lung

Answer 15

Volume time curve | Peak flow

Answer 16

``` Spirometry Noseclip Inhales to TLC Wraps lips around mouthpiece Exhales as hard+ fast as possible Exhalation continues until RV= reached/ 6 seconds passed X axis= Time (s), Y axis= Volume (L) Increase sharply at beginning, plateau ```

Answer 17

FVC= forced vital capacity, highest volume on curve, empty lungs as quickly as possible, restrictive disorder has a much lower value FEV1= Forced expiratory volume, volume expired in 1 second, obstructive disorder has a much lower value but restrictive doesn’t FET= Forced expiratory time (don’t need to know much, it’s how long it took for plateau to start) FEV1/FVC ratio compares how much air is coming out in 1 second Peak expiratory flow rate (L/min)= steepest part of graph

Answer 18

``` Noseclip Inhales to TLC Wrap lips round mouthpiece Exhale as hard+ fast as possible- don't have to reach RV Repeat twice+ take highest measurement Monitors asthma Peak expiratory flow rate(L/min) ```

Answer 19

COPD (Mild Obstructive disease): curve has moved upwards because lungs are larger in COPD (Surface area goes down but overall volume increases), peak is lower, coving because by the time you’ve emptied ¾ of your air the air moves through the small airways which has mucus and bronchoconstriction giving a lower flow rate Sever Obstructive Disease: As COPD gets worse, everything is exaggerated (vital capacity, coving, total volume increases, peak expiratory flow rate down) Restrictive: lower volumes and less access to air, peak is lower or the same (NOT SHOWN ABOVE), filling problem not a moving gas problem VEO: Expiratory curve is fine but inspiratory curve is blunted, still get enough air in but at a slower rate VIO: Inspiratory curve is fine but expiratory curve is blunted FAO: Like you’re compressing the tube

Answer 20

Most volumes and capacities reduced | Scar tissue formation= less elastic, restricting expansion of the chest at most volumes

Answer 21

Small decrease At start of tidal, pulls the parietal pleural membrane away from the lung Increases partial vacuum in the intrapleural space