Aspiration lung injury

1. Large volume pulmonary
aspiration syndrome
David B. Seder MD, FCCP, FCCM
Richard R. Riker MD, FCCM

2. Case presentation
• 58yo female with HTN became sweaty, nauseated,
took aspirin, and laid down to rest.
• 2h later spouse reported she had difficulty moving the
right side and speaking, vomited
• Tx MMC: aSAH, intubated, EVD, coiling
• On intubation posterior oropharynx was a pool of
brown fluid
• Early hypoxemia requiring high FiO2 post-intubation

3. Case presentation (2)

4. Case presentation (3)
• Vasospasm requiring multiple IA therapy, DCI
• Severe hypoxemic respiratory failure
– Alternating AC/PCV with low VT
– Paralytics, diuresis
– Proning - 2 separate episodes
• Sputum: initially PMNs only, then MDR
Pseudomonas superinfection
• Trach at day 18, slow recovery

5. Microaspiration v. Macroaspiration
• Continuous penetration of
secretions past ETT into
lungs
• Increased bacterial colony
counts and decreased
resistance lead to infection
• Progressive and insidious
• Large volume with
potential for respiratory
failure or arrest
• Gastric acid denudes
microvilli in airways
• Massive posterior/basal
infiltrates, usually R>L
• Severe & sudden
hypoxemia – but not always
immediately evident on
imaging

6. Is it pneumonitis or pneumonia?
Large volume aspiration Pneumonitis/ALI
ARDSPneumonia
Bacterial
superinfection
Denuded
respiratory
epithelium
Chemical lung
injury

7. “PEEP responsiveness”
•Diffuse edema/injury
•Responds to ↑PAW with
improved compliance and
oxygenation
“Position responsiveness”
•Regional infiltrates
– Often posterior
•Changes to positioning
improve V/Q matching
Day 4
Day 11
USE PEEP
USE PRONING

8. Basic ARDS “hygiene”
• Lung protective ventilation
– Low tidal volumes (4-6cc/kg)
– Adequate PEEP to prevent
atelectrauma and optimize
recruitment
– Avoidance of barotrauma and
minimize biotrauma
– Avoidance of oxygen toxicity
• Dry lungs when tolerable
• Rescue modes…?

9. Proning improves V/Q
• Most trials demonstrate
improved oxygenation and
ventilation
• One RCT and several
meta-analyses suggest a
mortality benefit with
severe ARDS
• Rapid and durable
response of gas exchange
Anesthesiol Clin 2007; 25(3): 631

10. PROSEVA: RCT Prone
Position• Intubated <36 hours with severe ARDS (P/F
<150 over 12-24 hours, 6 ml/kg IBW, Pplat
<30), ≥16 hours prone
– 237 patients prone, 229 patients supine
– 28-day mortality 16.0% Prone vs 32.8%
Supine, p<0.001
• Stopped proning when P/F >150 on ≤10 cm
PEEP and FiO2 ≤ 0.6 at least 4 hours since last
prone positioning
Guerin C. NEJM 2013; 368: 2159-68

11. PROSEVA
Guerin C. NEJM 2013; 368: 2159-68

12. PROSEVA Prone Position
Guerin C. NEJM 2013; 368: 2159-68
2 Weeks!

13. Prone Positioning
Lee MJ. Crit Care Med 2014;42(5):1252-62

14. Prone Positioning
• 9 RCTs with 2165 participants (10 publications).
• Short- and longer-term mortality (6 trials) demonstrated RR 0.84 -
0.86 favoring prone position, but CI 1.02 and 1.03
• Subgroup analyses (mortality) identified 3 important groups:
– Recruited within 48 hours of meeting entry criteria (5
trials, 1024 participants, RR 0.75 (0.59 - 94)
– Proned ≥16 hours per day
(5 trials, 1005 participants, RR 0.77 (0.61 - 0.99)
– More severe hypoxemia
(6 trials, 1108 participants, RR 0.77 (0.65 - 0.92)
Bloomfield R. Cochrane Database of Systematic Reviews 2015
(11):CD008095

15. Proning in ARDS
• First maximize lung protective
ventilation
• Always consider proning for
severe ARDS
• Get a team and develop
experience/expertise
• Lots of potential errors and
sources of harm – prepare!
• Tends to be very good for large-
volume aspiration events
https://www.youtube.com/watch?v=Jb_WUNggwdM

16. Questions?