A-a gradient_______? - uragan

[ArchivalUser]

Which of the following conditions are characterized by normal / increased A-a gradient?

1. chronic bronchitis
2. croup
3. bronchial asthma
4. barbiturates
5. lung athelectasis
6. pulmonary edema
7. amiodoron
8. RDS
9. propranolol
10. bleomycin
11. pulmonary thromboembolism
12. kyphoscoliosis
13. high altitude
14. left to right shunt
15. right to left shunt

Thank You

[ArchivalUser]

All these situations can cause inc. A-a gradient

PULMONARY EDEMA..........................diffusion defect.
AMIODARONE...pulmonary fibrosis.....diffusion defect.
BLEOMYCIN......pulmonary fibrosis.....diffusion defect

RDS..............................................ventilation defect
LUNG ATHELECTASIS.....................ventilation defect.

PULMONARY THROMBOEMBOLISM......perfusion defect

RIGHT TO LEFT SHUNT........venous blood bypass the lung and enterss the arterial circulation...dec paO2.(TOF)

Ventilation-perfusion imbalance -also known as V/Q mismatch (asthma, COPD)
Propranalol...I think its effect very similar to the asthmatic patient...bronchoconstrictor??


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If lack of oxygenation is proportional to low respiratory effort, then the A-a gradient is not increased..

4. barbiturates
12. kyphoscoliosis
13. high altitude

please confirm my answer.Thank you

[ArchivalUser]

Right

but, what abt COPD and High altitude? are there any changes in A-a gradient?

[ArchivalUser]

high altitude- A-a norma
COPD - should go up (inc)

[ArchivalUser]

@Lanna in Goljan it says A-a gradient is normal in COPD....and I agree with that.

PATIENTS WITH CHRONIC BRONCHITIS(eg) SUFFER FROM CHRONIC ACIDOSIS, INC. IN CO2 IN ALVEOLAR SAC PRODUCES CORRESPONDING DECREASE IN O2 ...

if I am wrong correct me..please

Thank YOU

[ArchivalUser]

Hi Uragan :-)
Ok, what your favorite Goljan say about V/Q mismatch?
Do you agree that any COPD ( for example emphysema) has V/Q mismatch ?
V/Q mismatch- is 100% inc .of A-a gradient .

[ArchivalUser]

A high V/Q ratio decreases paO2 and increases paCO2. This finding is typically associated with pulmonary embolism (where blood circulation is impaired by an embolus). Ventilation is wasted, as it fails to oxygenate any blood. ****A high V/Q can also be observed in COPD as a maladaptive ventilatory overwork of the undamaged lung parenchyma.

*from wiki....

@lanna, thanks. hope i will understand this better when i get to the qbanks...like UW