Thread by @PittIMPOCUS

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#IMPOCUS and thoracentesis case here - with a particular focus on pleural physiology, for discussion/eduational purposes

We see the following X-ray...
See thread below for the story leading up to this. Let’s try to sort out what is going on and what to do next.

#FOAMUS

2/Tagging POCUS friends/recent participants @SonoInternist @DRsonosRD @jelevenson @ria_dancel @msenussiMD @trobertson8 @G2Disrupt @IM_POCUS @buckeye_sanjay @benjikmathews @POCUS_Society @kyliebaker888 @CaseMcQuade @MedEdPGH @HeyDrNik @tweebui @UltrasoundJelly @5MinSono @awfujita

@laxswamy @bensmithwv @karthi8913 @pocusfoamed @POCUSAcademy @InternFrench @acrisol1 @curromir @greggmccordMD @DrToby1 @GrantTurnerMD @RMarieW1 @ameeshisath @rogeralver @peters_braden @jmcarvas @pkramer88 @virenkaul @iceman_ex @cianmcdermott @PeterMarogil @LMSaxhaug @antonyashton

@fsvalente_ @fluidloading @fluidloading @OAmidiMD @aykcng @DrFaustoBarrera @HToptay @Cometin007 @PeterMarogil @cianmcdermott @UCUltrasound @POCUSClub @JCHCheung @fsvalente @Cometin007

3/

Rewinding back to the beginning of the case, hours before the above CXR...

A middle-aged man with no PMH p/w progressive shortness of breath x several months. He normally has a “smoker’s cough” but recently his cough has increased and he is finding it harder to breathe.

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T 98, HR 98, BP 110/70, RR 20, SpO2 92% on 2L. Exam revealed reduced breath sounds R chest, dullness to percussion of R chest, reduced R sided tactile fremitus. CXR revealed opacification of R hemithorax with slight left mediastinal shift. Seemed c/w pleural effusion.

5/
POCUS revealed the following

6/ Thoracentesis was performed (for diagnostic purposes, as well as therapeutic removal of fluid) at this site. 60 cc syringe was used to remove fluid, along with tubing and 3-way stopcock to prevent air re-entry.

7/ After 1.1 L was removed, air started to enter the syringe, in addition to a small amount of fluid. All connections were inspected and all seals were tight, with no leaks. Pt reporting feeling well. No cough or CP. Soon only air (no fluid) was entering syringe with aspiration.

8/ At this point procedure was stopped, occlusive dressing was placed over catheter and catheter was removed. There was concern for pneumothorax, so POCUS was performed (these next 4 are representative images)

R lung, upper anterior chest

9/ R lung, upper anterior chest, with M mode

10/ L lung, upper anterior chest

11/ L lung, upper anterior chest, with M mode

12/ Pt reported feeling better than before the procedure. Said he was breathing comfortably. HR 66, BP 136/74, RR 16, SpO2 95% RA...

After a period, CXR shown at top of thread was obtained

13/ Would you like any additional information? What is going on here? What to do next?

Time to wrap up the case, and share a few key points

1) Should US always be used for thora?
2) Causes of post-thoracentesis PTX
3) Physiology of PTX ex vacuo? how to recognize and manage?
4) Should we routinely measure pleural pressures during thora?

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This seemed to be a classic presentation of PTX ex vacuo. Because pt was doing so well, tube thoracostomy was not done urgently. Thoracic surgery was consulted, and decision was made to observe. Fluid studies revealed transudate. CT chest requested, results not yet available

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1) Should US always be used for thora? Yes. According to SHM (with extensive literature backing)
-reduce incidence of PTX and visceral laceration
-increase success rate
-identify complex pleural features, and quantify volume, to aid decision-making
-understand needle depth

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2) Causes of post-thoracentesis PTX include the following
-lung laceration by needle or catheter
-bleb rupture
-unintentional air entry through catheter (can ppx w 1 way tubing. stopcock can help but not perfect)
-non-reexpandable lung (PTX ex vacuo)

emcrit.org/pulmcrit/pneum…

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3) Physiology of PTX ex vacuo. Non-reexpandable lung, with poor visceral pleural compliance leads to increasingly negative intrapleural pressures with even with limited additional volume removal. Aspiration --> negative IP pressure --> air entry from lung or along catheter.

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3b) Non-reexpandable lung can be due to
-trapped lung (thick visceral pleural rind). Maye amenable to decortication
or
-lung entrapment (collapsed portion of lung, often due to malignancy). Not for decortication (note effusion often transudative, due to pressure mechanism)

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3c) Management of PTX-ex-vacuo.
-discussion is nuanced over small bore pigtail vs no drainage. Our practice would be to involve thoracic colleagues or other experts. See expert comments in the thread.
-may be utility to air-contrasted CT to assess pleural thickening

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3d) In this case, immediate reaction to post-thora CXR was to worry, and consider emergent chest tube. But first step was to go back to bedside and assess pt. Everything fit for PTX-ex-vacuo, so tube placement was not emergent, could take time to make a good decision.

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4) Should we routinely measure pleural pressures?
Data seems equivocal. Might consider if concern for trapped lung. Thanks to @BegMoeez for reference thelancet.com/journals/lanre…

Does anyone do this w/ simple tubing (as below), rather than dedicated manometer? Or too imprecise?

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Overall key points
-POCUS is key in performing thoracentesis
-PTX ex vacuo is an increasingly common cause of post-thora PTX in the ultrasound era. It is worth recognizing the illness script and understanding the physiology and mgmt

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As always, thanks to all our POCUS friends/participants for the insightful discussion, and we welcome additional input on this.

24/24

@SonoInternist @DRsonosRD @jelevenson @ria_dancel @msenussiMD @trobertson8 @G2Disrupt @IM_POCUS @buckeye_sanjay @benjikmathews @POCUS_Society @kyliebaker888 @CaseMcQuade @MedEdPGH @HeyDrNik @tweebui @UltrasoundJelly @5MinSono @awfujita

@laxswamy @bensmithwv @karthi8913 @pocusfoamed @POCUSAcademy @InternFrench @acrisol1 @curromir @greggmccordMD @DrToby1 @GrantTurnerMD @RMarieW1 @ameeshisath @rogeralver @peters_braden @jmcarvas @pkramer88 @virenkaul @iceman_ex @cianmcdermott @PeterMarogil @LMSaxhaug @antonyashton

@fsvalente_ @fluidloading @OAmidiMD @aykcng @DrFaustoBarrera @HToptay @Cometin007 @PeterMarogil @cianmcdermott @UCUltrasound @POCUSClub @JCHCheung @fsvalente @Cometin007 @MarkusZiesmann @lalelaille @WesAldredMD @Rchout @lzavorszky @Donicme @OtisBRickman @BegMoeez