Journal Club
Naveed Hasan
Jan 5, 2011
Pleural Ultrasound Compared
With Chest Radiographic
Detection of Pneumothorax
Resolution After Drainage
BACKGROUND
 NON-INVASIVE
AND READILY AVAILABLE
(WHEREVER AVAILABLE!!!)
 Chest radiographs (CXR) miss 30% to 72%
of pneumothoraces because of their
anterior location1
 “DEEP SULCUS SIGN” can only detect less
than one quarter of the anterior PTXs2
 Pleural Ultrasound (PU) is more sensitive in
detection of PTX3,4
Hypothesis
 PU
is more accurate in assessing resolution
of PTX after Chest Tube drainage
Study Design:
 Prospective
Observational study
 Single center trial
 Specialized 4-bed PTX Unit in France
Patient Selection
 All
Patients with PTX were eligible, except
- Subcutaneous emphysema
- Use of mechanical ventilation
End Points:
the number of residual pneumothoraces
diagnosed by PU, including those not
identified by CXR
 The therapeutic impact of PU use
 The time to obtain CXR and PU results;
and
 the residents’ learning curve for using PU

Methods
 All
pneumothoraces were drained using a
dedicated device, Pleurocath 8 French
 connected to water seal vacuum system
regulated to generate a depressurization
of 30 cm H2O.
 pleural catheter patency check every 4 h
by nurses using 5 mL of saline
Ultrasonographic Identification
of Pneumothorax
 Ultrasound
-
-
diagnosis of pneumothorax
relies on three signs:
abolition of lung sliding,
the A-line sign (the presence of A-lines
without B-lines, The presence of B-lines
rules out pneumothorax diagnosis)
the lung point
Technique of PU
 performed
by a single investigator using a
portable SonoSite180 plus and a 7.5-MHz
linear probe with the patient erect
 probe was placed perpendicular to the
intercostal spaces and then moved along
the midclavicular line, the midaxillary line,
and along the outer edge of the scapula
Probe Position
Sonographic lung Zones
Definition of PTX
 Pneumothorax
diagnosis by PU was
defined as the abolition of lung sliding
plus the A-line sign
 Presence of lung point was also noted but
was not required for pneumothorax to be
suspected.
What you should see normally
 Lung
Sliding Sign
 A- Lines
 B - Lines (comet tail artifacts)
 Lung pulse +/-
Normal Lung Sliding Sign
 Produced
by sliding of visceral pleura
over parietal pleura
 >95% sensitivity for PTX
http://www.critcaresono.com/page.php?p
age=29
Video 9
Sea-Shore Sign in Normal Lung
 Seen
in M-mode
 Includes motionless parietal tissues over
pleural line and homogenous granular
pattern below it.
Lack of Sliding Sign
 PTX
 Pleural
Adhesion
 Mainstem Intubation
 Pulmonary Contusion
 ARDS
 Atelactesis
A- Lines
 “Reverberation”
Artifact
 Parallel to Pleural line
 Distance between A-lines is equal to or a
multiple of Visceral- Parietal Pleural
Interface (VPPI) or Lung Chest Wall Index
(LCWI)
The B-Lines (Comet-tail Artifacts)





Usually seen in the lower lung zones, laterally
or posteriorly
Originate at the VPPI and usually extend
down to the bottom of the picture
Usually 3-4 lines in one intercostal space
No of lines correlate with the alveolar
interstitial pattern
Presence of B-Lines rule out PTX
http://www.critcaresono.com/page.php?page
=29
Video 9
The B Lines…contd
The A-Line Sign
 Presence
of A-lines in the absence B lines
http://www.critcaresono.com/page.php?p
age=27
Video 11
The Lung Point
 Denotes
the edge of PTX
 Most specific sign for diagnosis of PTX
(100% specificity)
The Lung Point…M-Mode
The Lung Point
 http://www.critcaresono.com/category/L
ung/2
The Lung Pulse
excellent sign in the post-pleurodesis patient
 rhythmic "pulsations" at the pleural line reflect
the cardiac pulsations transmitted to the
visceral pleura
 Can only be seen when there is NO AIR
between the two pleural surfaces and is a
good alternative sign to look for when lung
sliding cannot be easily detected.
 Presence of lung pulse rules out possibility of
pneumothorax.
http://www.critcaresono.com/page.php?page
=27
Video 14

CXR and PU Indications

CXR and PU were performed in a doubleblind manner at the following times:
(1) 24 h after bubbling in the aspiration device
had stopped,
(2) 6 h after clamping the pleural catheter, and
(3) 6 h after removing the pleural catheter.
For pneumothorax recurrence, additional CXR
and PU were performed at these same time
points.
Confirmation of Pneumothorax
Identified by PU But Not CXR
 aspiration
with a syringe of >10 mL of air
through the pleural catheter if it has
previously been clamped, or
 by CT scan in other cases
Statistics
 The
positive predictive value (PPV) of PU
for pneumothorax diagnosis was
calculated using the standard formula.
Results





51 patients screened over 18 months, 7 were
excluded.
All had unilateral PTX
Cause of PTX as follows
- Primary Spontaneous (70%)
- Traumatic (15.9%)
- Secondary to emphysema (9%)
- Iatrogenic (4.5%)
Mean stay in ICU was 3.9 +/- 1.5 days
84 % patients were treated successfully, 16%
required surgical intervention
Results…contd
Results…contd
*5 confirmed by CT scan and 8 confirmed by aspiration of air
Therapeutic Intervention
 Aspiration
switched on or maintained longer
than predicted, n = 8
 Unblocking the pleural catheter, n = 3
 Introduction of second pleural catheter, n =1
 Surgical intervention, n = 1
Results…contd
 PPV
of PU was 100% for diagnosing
residual PTX after drainage of primary
spontaneous PTX with or without the
presence of lung point.
 PPV of PU was 90% for diagnosing residual
PTX after drainage of non-primary
spontaneous PTX without lung point and
100% in the presence of lung point.
PU Learning Curve
 Six
ICU residents took part in the study
 Each received 2h of training with no
previous USG experience
 Mean no. of exams performed by each
resident was 27+/- 12
 There was no significant difference
between the results of resident and
primary investigator
Critical Analysis
 Use
of small size catheter for PTX drainage
- Large-bore Chest tube vs 8 F catheter
 Confirmation of PTX by non-standard
method (aspiration of air)
 Impact on patient outcome
- clinical significance of detecting
occult PTX
 Generalizability
- Majority of study population had
primary spontaneous PTX
CHEST TUBE vs PleureX
J THORAC CARDIOVAS SURG 2011;141:683-7
-
Retrospective study on non-trauma patients
12 F catheter was used
399 catheters were placed for PTX
75% were primary PTX
Success rate was 93 %
Failure mostly secondary to dislodgment
Confirmation of
Residual/Occult PTX
 Gold
standard is CT scan
 Does 10 ml of air aspiration corresponds to
residual/occult PTX on CT scan???
Clinical Significance of Occult
PTX
Injury, Int. J. Care Injured 40 (2009)928-931
-
Retrospective review of 1881 Blunt trauma patients
307 PTXs were found, 68 were occult
35/68 received Tube thoracostomy, 33/68 were observed
No Tension PTXs seen in each group
Mortality was similar
LOS was significantly shorter in observation group
Conclusions:
 PU
is more sensitive in diagnosing
Pneumothoraces, Primary spontaneous
and post-procedural
 The clinical significance of diagnosing
these small PTXs missed by CXRs remains
to be determined
Thank You
References:



1. Soldati G , Testa A , Pignataro G , et al . The ultrasonographicdeep
sulcus sign in traumatic pneumothorax . Ultrasound Med Biol . 2006 ; 32 (
8 ): 1157 – 1163
2. Ball CG , Kirkpatrick AW , Fox DL , et al. Are occult pneumothoraces
truly occult or simply missed? J Trauma . 2006 ; 60(2):294-298.
3. Lichtenstein DA , Mezière G , Lascols N , et al . Ultrasound diagnosis of
occult pneumothorax . Crit Care Med . 2005 ; 33 ( 6 ): 1231 - 1238 .