Respiratory Ards

Front 1

2 types of respiratory failure

Back 1

1. Gas exchange failure (oxygen does not leave the alveoli to enter the blood)
2. Ventilatory failure (muscular failure)

Front 2

Under normal circumstance, PAO2 should equal...

Back 2

PaO2

Front 3

A difference in gradient between PAO2 - PaO2

Back 3

AaDO2 (we learned this as the A-a difference)

Front 4

Equation for Alveolar Oxygen Partial Pressure (PAO2)

Back 4

[(Pbar - PH2O)*FiO2] - [PaCO2(1/RQ)]
i. If PaCO2 is 40, like normal, the equation resolves to a PAO2 of 104 (as expressed in Ritucci's lecture)

Front 5

Normal AaDO2 in healthy adult

Back 5

5, but can increase to 20 in elderly. Values higher than that are abnormal

Front 6

Major determinant of drive to breathe

Back 6

Acidic PaCO2

Front 7

What is the secondary determinant of dive to breathe?

Back 7

PaO2 only in conditions where chronic CO2 insensitivity exists

Front 8

Normal O2 saturation

Back 8

i. true physiological drive to breathe
ii. > 90%

Front 9

Sequelae of lowered O2 saturation

Back 9

i. Polycythemia
ii. Pulmonary vasoconstriction - PHT
iii. PHT - Cor pulmonale, RVF
iv. Cyanosis

Front 10

2 dangers of oxygen therapy

Back 10

i. Respiratory shutdown in CO2 insensitive patients
ii. Toxic radical formation

Front 11

Intracardiac causes of shunt in lungs (Low V)

Back 11

PFO, VSD, ASD, PDA

Front 12

Intrapulmonary causes of shunt in lungs (Low V)

Back 12

Pulmonary edema, pneumonia, hemorrhage, hepatopulmonary syndrome, atelectasis

Front 13

Causes of diffusion block (V is normal, Q is normal, V cannot get to Q)

Back 13

1. Alveolar-Capillary interface thickening
2. Fibrosis
3. Granulomatosis
4. Interstitial tumor
5. Thickened vessels
6. Alveolitis

Front 14

Chronic diseases process effect on vasculature

Back 14

The number (numerical density) of pulmonary BV's will decrease

Front 15

Causes of lung restriction and impaired diffusion

Back 15

1. Pneumonias (all)
2. Atelectasis (drowning)
3. Surgical resection
4. Tumor
5. Ventilatory failure (muscles cannot assist lungs in reaching full volume)

Front 16

Shunt: PaO2, AaDO2, PaCO2, and oxygen therapy

Back 16

PaO2 - drops
AaO2 - increases
PaCO2 - normal or drops
No change with oxygen therapy

Front 17

General trend of AaDO2 values in various respiratory disease states

Back 17

Almost uniformly decrease, except that hypoventilation does not cause a change in gradient (both values are lowered concomitantly)

Front 18

If the radius of the curvature of the diaphragm is increased (as in COPD) . . .

Back 18

the resultant pressure conferred to the abdominals will be less, and therefore the abdominal wall will not move as far outward or contract as far inward on expiration. LESS PRELOAD.

Front 19

Factors influencing respiratory afterload

Back 19

i. Airway caliber
ii. Lung compliance
iii. Chest wall compliance

Front 20

Factors influencing respiratory contractility

Back 20

i. Fatigue
ii. Non-fatigue muscular weakness
iii. Reduced blood flow

Front 21

Why does mechanical ventilation improve survival in shock?

Back 21

Blood that is being preferentially diverted to the respiratory muscles as opposed to brain and heart will be redistributed (the lungs do not have to work as hard)