week 6 ARDS

Question 1

define ARDS

Answer 1

characterized by acute inflammation and fluid accumulation in the lungs

Question 2

what are the alterations of the lungs for ARDS

Answer 2

1. caused by injury from disease infection or trauma
   -pulmonary capillaries become engorged or filled w/excess blood
   -permeability of the alveolar-capillary membrane increases
   -interstitial and intra-alveolar edema and hemorrhage
   -scattered areas of hemorrhagic alveolar consolidation
2. increased hyaline membrane and decreased alveolar surfactant

Question 3

define cardiogenic pulmonary edema

Answer 3

-hydrostatic pressure
hydrostatic>oncotic pressure
-due to heart problems

Question 4

define non cardiogenic pulmonary edema

Answer 4

non hydrostatic pressure
-increased total lung water despite normal hydrostatic pressure due to capillaries itself due to inflammation or injury

Question 5

what are common causes of ARDS

Answer 5

1. sepsis-lactate>1.0 (severe infection that spreads throughout bloodstream leads to inflammation response)
   2.aspiration
   3.pneumonia-community acquired
   4.severe trauma-bilateral lung contusion
   5.oxygen toxcity-prolonged exposure to FiO2>60%

Question 6

what are some structural changes of the lungs caused by ARDS?

Answer 6

1. interstitial and intra-alveolar edema & hemorrhage
   2.alveolar consolidation
   3.intra-alveolar hyaline membrane
2. pulmonary sufactant deficiency or abnormalities
3. atelectasis

Question 7

define the berline diagnostic criteria

Answer 7

1. respiratory symptoms associated w/ ARDS have manifested w/in 1 week of a known clinical event -a new or worsening symptoms over the past 7 days

2.respiratory failure cannot be fully explained by heart failure or fluid overload

3.moderate to severe impairment of oxygenation must be present
-P/F ratio

Question 8

what are the P/F ratios?

Answer 8

> 400=normal lung
300-399=mild pulm dis
200-299=acute lung injury
<200= ARDS

Question 9

what are the clinical manifestations of ARDS

Answer 9

1. atelectasis
   2.consolidation
   3.increased alveolar-capillary membrane thickness

Question 10

physical examination of ARDS

Answer 10

1. vital signs:
   -tachypnea
   -tachycardia
   -hypertension

2.substernal&intercoastal retractions

3.cyanosis

4.chest findings:
-dull percussion note
-bronchial breath sounds
-crackles

Question 11

PFT/ DLCO

Answer 11

-restrictive

DLCO:
decreased

Question 12

ABG

Answer 12

1. mild/moderate
   -acute respiratory alkalosis

2.severe ARDS
-acute respiratory acidosis

Question 13

hemodynamics of ARDS

Answer 13

⬆️:CVP ⬆️, RAP ⬆️, PAP ⬆️, PVR ⬆️

N or ⬇️: PCWP,SVR

N or ⬆️: CO,SV,CI

Question 14

chest radiograph of ARDS

Answer 14

1. increased opacity,diffusely through out lungs
2. ground-glass appearance

Question 15

explain the therapeutic approach for ARDS complications

Answer 15

1. baratrauma: significant decrease in static lung compliance. use low Vt

2.delirium: these pt will be intubated/sedatives (titrate)

3.deep vein thrombosis: anticoagulants & preventative therapies

5. pneumonia: treatment meds (antibotics)
6. corticosteroids

Question 16

What are the RT protocols for ARDS

Answer 16

1. Oxygen therapy
   2.lung expansion therapy
   3.mechanical ventilator

Question 17

what are the normal initial settings for mechanical ventilation

Answer 17

Vt= 6-8mL/kg of ideal body weight

frequency=10-20 breaths/min

Question 18

mechanical ventilation initial setting for ARDS

Answer 18

Vt= 4-6 mL/kg of ideal body weight
frequency=15-25 breaths/min

Question 19

ARDS protocol

Answer 19

1.initial Vt=6mL/kg pbw
2.reduce Vt by 1mL/kg pbw until Vt=4mL/kg
3.set frequency to pt baseline Ve (not>35bpm)
4. plateau pressure(Pplat)=25-30cmH20 (static compliance)
-measured using inspiratory hold
-measured the pressure inside alveoli vs elastic recoil of lung tissue

5. PEEP and FiO2: FiO2 to 60% then add PEEP

6.pH goal: 7.30-7.45
-titrate frequency depends on pH
-frequency never >35bpm

7. permissive hypercapnia
   -PaCo2 allowed to increase as trade off to protect lungs
   -should not progress into severe acidosis (pH<7.20)
8. if alkalosis occurs
   -decrease frequency if possible

Question 20

explain what the adjuctive strategies are?

Answer 20

1. prone positioning-chest&face down
   -ARDs pronounced in posterior region

2.neuromuscular blockade
-paralytic agent to allow synchrony to mech vent
-enhance compliance

3. inhaled vasodilators
   -NItric oxide
   -promotes increased blood flow to good alveoli
   -imprves V/Q mismatch
   -improves Oxygenation
   -prostacyclin * used as alternative to NO
4. extracorporeal membrane oxygenation (ECMO)
   -diverts large portions of CO to an artificial lung
   -O2 and CO2 exchange