7 - Pneumothorax Flashcards
What is a pneumothorax?
Free air entering the potential space between the visceral and parietal pleura
Not potential space anymore
Primary v secondary pneumothorax?
Primary: no lung disease
- spontaneous
- 2/2 trauma
Secondary: underlying lung disease
What keeps the lungs “inflated”?
The parietal and visceral pleura are in close apposition
Pleural space is neg pressured at -5mmHg (fluctuates w inspiration/expiration)
What occurs when a primary pneumothorax erupts?
Primary spontaneous pneumothorax occurs when a subpleural blep ruptures, disrupting pleural integrity
Primary pneumothoraces usually occur?
At the lung apex
What happens with a secondary spontaneous pneumothoraces?
Disruption of the visceral pleura occurs 2/2 the underlying pulmonary disease processes
Simple explination for pneumothorax?
The lung ruptures
Air follows the path of least resistance, so rather than go out the mouth hole it goes out the new lung hole into the potential space
This creates a disruption in the pleural space creating a positive pressure
Now the lung starts to collapse
When does a tensionpneumothorax develop?
Inhaled air accumulates in the pleural space but cannot exit due to a check-valve system
Once pressure is >15mmHg the heart and vessels shift contralaterally
This affects venous return, diastolic filling and CO
The crushing pressure on the great vessels and heart leads to a?
Ventilation-perfusion mismatch —> hypoxia and shock
Tension pneumo with a chest tube?
Yeah if you dont do it right and gas egress is obstructed
Classic symptoms of primary spontaneous pneumo?
Sudden onset of: - dypsnea - chest pain that is —-ipsilateral —-pleuritic
Profound dypsnea is rare unless they are already sick
How long does the pleuritic component of the pneumothorax take to resolve?
24hrs
MC physical finding with spontaneous pneumo?
Sinus tachycardia
If pneumothoraces are small classic findings may not present, these findings are?
- ipsilateral decreased breath sounds
- hyper-resonance to percussion
- decreased/absent tactile fremitus
With traumatic pneumo ___ has a positive predictive value of 86-97%?
Ipsilateral decreased breath sounds
Clinical hallmarks of tension pneumo?
Tracheal deviation (contralateral)
Hyperresonance
HOTN
Sig dypsnea
Symptoms that are not commonly found?
Cough
Exertional complaints
Consider pneumothorax with pts who have chest pain but it also could be?
Pleurisy
Pleural effusions
Infiltrates
Shingles
Look like pneumothorax
This bedside test is super sensitive and specific for pneumo?
US
US will show?
Seashore:
Movement of lung (ocean) against the stationary chest wall (shore)
What does normal lung look like on US?
Normal lung sonographic reverberation distal to the pleura that looks like a comet tail and sliding sign of movement of visceral pleura along parietal pleura
Basically a wedge of lung and 2 rib shadows
What US mode do you use?
M mode
- motion mode
14-19 have pics
CXR kinda sucks for pneumo but ___ is pretty great
CT
- not only can it see more pneumos
- it can show pulmonary blebs
21-25 has pics
ED treatment goal?
Eliminate intrapleural air
You suspect tension pneumothorax, now what?
Dont wait on radiology
- needle D
- tube thracostomy
what is SWAG? Give me an example
SWAG - scientific wild ass guess
Example: w/o supplemental o2 a 25% pneumo would take approx 20 days to resolve
Who gets to go home?
You can do observation for small, stable pneumothoraces
- observe x 4hrs on o2 then repeat CXR
If still good have them return in 24hrs
- Return to the ED not PCM
What is the decision to use aspiration or a tube thoracostomy based on?
Likelihood of recurrence and likelihood of spontaneous resolution
Who tends to need a chest tube?
Likely to recur and need a chest tube:
- Underlying pulm disease
- Large pneumo
- Inability to return to hospital
- Unable to tolerate pneumothorax (poor cardiac reserve)
Complications of pneumo?
Those due to
- hypoxia
- Hypercapnia
- HOTN
Reexpansion injury Intercostal hemorrhage Lung parenchymal inj Empyema Tube malfunction (air leak)
When are reexpansion lung injurys likely to happen?
They are unlikely but seen w:
- collapse of >72hrs
- large pneumothorax
- rapid reexpansion
- negative pleural pressure suction >20cm
Tx for reexpansion injury?
Observation
Oxygen
“These guys do great”
What is pleurodesis?
Used for recurrence prevention on:
- 1st spontaneous pneumo
- 2nd ipsilateral spontaneous
- 1st contralateral pneumo
- bilateral spontaneous pneumo
- 1st episode of 2ndary pneumo
- recurrent high-risk activities (skydiving, scubadiving)
What is iatrogenic pneumo?
Subset of traumatic pneumo
- more common than spontaneous
Iatrogenic - hospital induced
What causes iatrogenic pneumos?
Transthoracic needle procedures (needle biopsy, thoracentesis)
Subclavian vein catheterization
This is often under-detected and underreported, honestly we don’t do these procedures on healthy patients, we may not even notice we punctured the guys lung who had 6 GSWs to the chest
Techniques to reduce iatrogenic pneumos or at least find them early?
US guidance for central lines and thoracentesis
CXR is routine but often misses the pneumo so not useful
Tx for iatragenic pneumo?
The same as spontaneous
Its just a small pneumo (hopefully)
Prob do a simple catheter aspiration
Concern for pneumothoracies, particularly for military applications?
Boyle’s law - tensions are more likely when you are transported in aircraft
We may have trouble evacuating these people out of theater
High-altitude flying is not recommended for:
7-14 days after resolution
“Youll never catch me…”
Scubadiving - same thing pressure changes and stuff
- no scuba w hx of pneumos
- unless treated w surgical pleurectomy
