The Occult Pneumothorax: Issue or Incidental

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The Occult Pneumothorax Issue or Incidental?

• AW Kirkpatrick CD MD FRCSC
• Regional Medical Director of Trauma, The Region
  Formerly known as Calgary

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Learning Objectives

• Define what is meant by the term occult
  pneumothorax
• Define the epidemiology of occult pneumothoraces
• Define the diagnostic strategies to detect occult
  pneumothoraces
• Define the controversies in the occult
  pneumothorax management
• Define the risks involved in either treating or
  observing occult pneumothoraces

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The Message

• Pneumothoraces (PTXs) in 1/5 victims of major
  blunt trauma found alive
• Not treating tension PTXs is a leading cause of
  preventable death
• CXR misses at least half of all PTXs seen on CT
  scan (at FMC)- called OPTXs
• We dont really know what to do
• Currently no organized approach and the current
  treatments are widely divergent
• Iatrogenic harm does rise in Rx
• We hope to learn more in the future through the
  occult pneumothorax trial hopefully in your
  hospital

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AW Kirkpatrick Disclosure

• I do not have an affiliation (financial or
  otherwise) with any commercial organization that
  may have a direct or indirect connection to the
  content of my presentation
• I have received unrestricted research funding to
  investigate the relevance of occult
  pneumothoraces from the
• David Thompson Award of the Canadian Intensive
  Care Foundation (CICF)
• Canadian Trauma Trials Collaborative (CTTC) of
  the Trauma Association of Canada

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A Case

• 25 year old female in a small car rollover MVC
• Closed head injury
• Grade II splenic laceration treated
  non-operatively
• Open fumur fracture treated with an IM nail
• Indistinct mediastinal contour

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CXR
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(No Transcript)
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Learning Objective 1Define the term Occult
Pneumothorax

• A PTX identified on an abdominal CT scan that was
  not seen on a preceding supine AP CXR1

Wall SD, Am J Radiol 1983
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Rationale Thoracic Trauma

• Responsible for 25 of all trauma deaths
• Pneumothoraces are the most common serious
  intra-thoracic injury following blunt trauma1,2
• 1/5 incidence in victims of major trauma found
  alive3

1ATLS Course, 2Richardson 1996 3Di Bartolemeo, J
Trauma 2001
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Management?
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ATLS Recommendations

• 2008 Recommendations

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Alternate Opinions

• A subset of patients with blunt OPTXs requiring
  positive pressure ventilation may be safely
  managed without tube thoracostomy.
• 16/20 vented patients avoided a chest tube

Barrios et al, Am Surg 2008
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Debate
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Second Opinions from other Trauma Surgeons
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Multi-Disciplinary Decision Making
Medical, Nursing, Respiratory Therapy
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Anaesthesia Consultation
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Internal Medicine Consultation
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Back to the Books Literature Search

• PubMed literature search for previous randomized
  controlled trials on the occult pneumothorax

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PubMed Search Occult Pneumothorax AND
Mechanical Ventilation LIMITED TO RCTs

• 1 single study!!!
• Enderson BL, Abdalla R, Frame SB, Casey MT, Gould
  H, Maull KI.Tube thoracostomy for occult
  pneumothorax a prospective randomized study of
  its use.J Trauma. 1993 Nov 35(5) 726-9
  discussion 729-30. PMID 8230337 PubMed -
  indexed for MEDLINE

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Related Articles

• Reveals a second study
• Brasel KJ, Stafford RE, Weigelt JA, Tenquist JE,
  Borgstrom DC. Treatment of occult pneumothoraces
  from blunt trauma.J Trauma. 1999 Jun 46(6)
  987-90 discussion 990-1. PMID 10372613 PubMed
  - indexed for MEDLINE

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Results (Enderson 1993)

• 3261 trauma patients admitted over 18 months
• 709 (21.7) had abdominal CT scanning
• 40 (5.6) had OPTXs
• 21 randomized to observation
• 19 randomized to chest tube

University of Tennessee, Knoxville, TN
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Demographics
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Only 27 patients ventilated
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Positive Pressure Ventilation

• 15 ventilated with a chest tube

• 12 ventilated without
• a chest tube

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Complications - Enderson

• Significantly more major complications in the
  observed group (plt0.02)
• 8/15 (53) patients on mechanical ventilation
  required a chest tube for PTX progression
• 3/15 (20) developed tension PTXs

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Conclusions Enderson 1993

• Patients with occult PTXs who require positive
  pressure ventilation should undergo tube
  thoracostomy

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Brasel 1999

• OPTXs defined as PTXs not seen on supine CXRs but
  seen on helical ABDOMINAL CT scan
• 39 patients with 44 OPTXs enrolled
• Randomized
• (bilateral PTXs randomized by patient)
• 18 chest tubes
• 21 observed

St. Paul-Ramsey Medical Center St Johns Regional
Health Center
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Results (Brasel 1999)

• 5126 trauma patients admitted over 18 months
• (1669) had abdominal CT scanning
• 86 (5.2) patients had OPTXs
• Not 5.9 as reported math!
• 39 (45) enrolled
• 21 randomized to observation (24 PTXs)
• 18 randomized to chest tube (20 chest tube)
• Demographics comparable - table

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Demographics
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Mechanical Ventilation

• 9 each group required ventilation
• 3 each group only for operative procedures
• Six each group longer than 24 hours ventilation
• No difference in ventilation days

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Outcomes in the Mechanical Ventilation Group
Brasel 1999

• No patient had respiratory distress related to
  an occult PTX or required emergent tube
  thoracostomy

• Observed with no chest tube
• 3 had PTX progression
• 2 on PPV had chest tubes placed (33 of this
  group)
• Chest tubes also placed for
• Retained hemothorax
• Increased pleural effusion
• Asymptomatic PTX progression
• Spinal surgery

• Chest tube placed
• No emergent chest
• 4 had PTX progression related to coming off
  suction

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Conclusions Brasel 1999

• Possible to safely observe patients regardless of
  the need for PPV or PTX size!!

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The (conflicting) World Literature

• 2 small studies with only 45 patients are the
  cumulative world experience for those randomized
  to clinical trial experience
• Diametrically opposed results

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Building the Case
Literature Review Can J Surg (2003) (in press)
Epidemiology and Incidence (J Trauma 2005)
Anatomic Distribution (Am J Surg 2005)
Diagnostic Errors (J Trauma 2006)
Complications (Can J Surg 2007)
Randomized Pilot Data to Power the Definitive
Trial (Am J Surg 2009)
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Literature Review

• Ball CG et al., The Occult Pneumothorax
• What Have we Learned from the Recent Literature?
  Can J Surg (in press) 2009

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Incidence
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How Common Are They?

• Incidence among all trauma patients 1- 64
• Most approximate 5-8 of patients with CT
• Up to 72 of all PTXs are first detected on CT
• Majority are greater than 50 occult
• Frequency depends on
• Extent of CT imaging
• Injury Severity
• Selected Cohort
• Increasingly common with accelerating CT use

Ball CG, Kirkpatrick et al., Occult pneumothorax
in the mechanically ventilated trauma patient,
Canadian Journal of Surgery, 2003.
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Management (including retrospective)
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OPTX Imaging

• Supine AP chest radiograph is the initial imaging
  test in most trauma patients
• Least sensitive of all plain radiograph
  techniques for diagnosing pneumothoraces (up to
  400cc)
• Images are more difficult to interpret
• Pneumothoraces do not appear in classic locations
• CXR is inaccurate in defining size and location
  of a pneumothorax

Trupka A et al. 1997 Cooke DA 1987 Chan SS
2003
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Occult Pneumothorax

• A PTX identified on an abdominal CT scan that was
  not seen on a preceding supine AP CXR

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Diagnostic Ultrasound Occult Pneumothoraces

• Lichtenstein 2005
• 357 hemithoraces
• Sens-95, spec 94
• Blaivas 2005
• 176 patients
• Sens 98.1, spec 99.2

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Needle Decompression of a tension pneumothorax

• Kirkpatrick et al., J Trauma 2009

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Lung Sliding Hearing Breathe Sounds
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With Pneumothorax the Normal Signs are Gone
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Lung Point Sign

• Reproduced with permission
• Lichtenstein, Critical Care Medicine
  2005331231-1238

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The Calgary ExperienceHow Common Are They?

• Trauma Registry study
• OPTX incidence 15 of all seriously injured
  patients with a thoracoabdominal CT scan
• OPTX incidence 6.1 of all registry patients
• 55 of all pneumothoraces were occult to supine
  AP CXR

Ball CG, Kirkpatrick et al., Incidence, risk
factors and outcomes for occult pneumothoraces in
victims of major trauma, Journal of Trauma, 2005.
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The Prospective Calgary Experience 4 yrs later

• PTX prospective incidence 26 of 405 patients
  receiving a thoracoabdominal CT had a PTX
• 76 of these were considered occult by the
  treating physicians

Ball CG, et al., Clinical predictors, Injury 2009
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Where are they anatomically?
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PTX Distribution

• Occult Overt Residual
• Apical 21 (57) 7 (58) 11 (42)
• Basal 15 (41) 7 (58) 16 (62)
• Lateral 9 (24) 7 (58) 10 (38)
• Medial 10 (27) 6 (50) 8 (31)
• Anterior 31 (84) 9 (75) 23 (88)
• Posterior 0 1 (8) 1 (4)
• Apical Only 6 (16) 3 (25) N/A

Ball CG, et al., American Journal of Surgery,
2005.
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PTX Size

• 89 PTXs
• 13 overt
• 49 OPTX
• 27 residual

Ball CG, Kirkpatrick et al., J Trauma
200559917-925
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Why Do We Miss Them?

• Group 1 Group 2 Group 3

• Sensitivity 21 23 9
• Specificity 100 89 89
• PPV 100 91 80
• NPV 21 19 17

Ball, J Trauma 2006
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Potential plain radiographic signs of an occult
PTX

• Double diaphragm
• Deep sulcus
• Hyperlucent hemithorax
• Sharpened cardiac silhouette
• Depressed diaphragm
• Apical pericardial fat sign

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Why Do We Miss Them?

• Group 1 Group 2 Group 3

• Deep Sulcus 7(78) 9(90) 3(75)
• Crisp Cardiac 1(11) 1(10) 0
• Pleural Line 1(11) 0 1(25)
• Total Dx 9(21) 10(23) 4(9)

Ball CG, Kirkpatrick et al., Are occult
pneumothoraces truly occult or simply missed?, J
Trauma 2006.
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How Should They Be Managed?

• OPTX
• Ventilated Non-Ventilated

• Total (N) 17 (35) 32 (65)
• Median ISS 34 22.5
• Received TT 13 (76) 10 (31)
• Required TT 1 / 4 (25) 1 / 22 (5)
• After PTX Progression

Ball CG, J Trauma 2005
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Complications of chest tubes

• Up to 30 of chest tubes
• Vascular Injury
• Pain
• Improper positioning
• Inadvertent tube removal
• Post-removal complications
• Longer hospital stays
• Empyema
• Pneumonia

• Etoch Arch Surg 1995, Bailey J Accid Emerg Med
  2000

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Chest Tube Complications at FMC

• Total 22 (17/76)
• Insertional
• Intercostal artery laceration 24 (4/17)
• Intraparenchymal lung placement 12 (2/17)
• Positional 53 (9/17)
• Infective
• Empyema 6 (1/17)
• Wound infection 6 (1/17)

Ball CG et al., are we training our residents?,
Canadian Journal of Surgery, 200750450-458.
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(OPTICC) Occult PneumoThorax In Critical Care
Trial

• Brain Injury Trauma Research Committee
• Departments of Critical Care Medicine Surgery
• Foothills Medical Centre

• Supported by
• Canadian Trauma Trials Collaborative
• Canadian Intensive Care Foundation

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OPTXs in the non-ventilated

• Stable observe
• Recommended daily CXR
• Place a tube if
• Becomes overt PTX
• Any distress
• Hemothorax

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Plan Randomization by the Trauma Surgeon

• Small or medium sized
• Ventilated
• No obvious need for a chest tube
• No respiratory concerns
• Expected to survive
• No perceived need to drain a hemothorax

Small or medium sized
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Exclude Large OPTX
Mid-coronal line
Large extends posterior to this line
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Exclusions

• Respiratory Distress
• Not Occult (Pneumothorax seen on CXR)
• Treating physicians feel a chest tube is
  warranted
• Not ventilated patient
• Hemothorax warrants drainage
• Large Occult Pneumothorax

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Outcomes

• Respiratory Distress
• Requirement for chest tubes
• Secondary
• ICU Days
• Hospital Days
• VAP
• Tracheostomy
• Chest tube complications

• Respiratory Distress
• Acute change from baseline of 0.2 in FiO2
• Pharmacologic paralysis for respiratory change
• Mechanical hand-bagging
• Prone ventilation
• Documentation of any adverse respiratory event in
  the chart

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Pilot Report

• OPTICC Pilot
• 24 enrolled with 2 exclusions
• Approximates largest series to date
  (Enderson-27-1993)
• Combined experience
• Calgary 17
• Quebec City - 7

Ouellet, Am J Surg 2009
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Preliminary Results

• OPTICC Results
• 9 chest tubes
• 13 observed
• 4 required non-urgent chest tube
• Respiratory distress
• 33 versus 46
• Mortality
• 22 versus 15

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Conclusions

• No observed difference in morbidity
• Study is practical and feasible

Quebec
Calgary
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Continuing Pilot Enrolment

• Quebec 12
• Calgary 29
• Sherbrooke 1
• Sunnybrook, Toronto - 12

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Proposal to the Canadian Institute for Health
Research (CIHR)

• Letters of Intent
• Vancouver (VGH)
• Edmonton (University)
• Toronto
• (Sunnybrook, St.Mikes)
• London (University)
• Sherbrooke
• Montreal (McGill)

• Letters of Intent
• Quebec (LEnfant Jesus)
• Ottawa (Civic)
• Calgary (FMC)
• OF course, anyone else that want to be involved

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Powered as a non-inferiority trial

• Randomized, non-blinded prospective trial of
  observing or draining the pleural space in
  stable patients with an OPTX
• Target recruitment
• 430 patients

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Learning Objectives

• Define what is meant by the term occult
  pneumothorax
• Define the epidemiology of occult pneumothoraces
• Define the diagnostic strategies to detect occult
  pneumothoraces
• Define the controversies in occult pneumothorax
  management
• Define the risks involved in either treating or
  observing occult pneumothoraces

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The real take-home!!

• Shouldnt we be enrolling this patient?

Doh Missed another patient!
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Thank You

• andrew.kirkpatrick_at_albertahealth
• services.ca
• OR
• andrew.kirkpatrick_at_calgaryhealth
• services.ca

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Take-home

• Pneumothoraces are very common and the right
  chest tube can save a life
• Half of all the PTXs we see are occult and we
  dont know what to do with them
• Unnecessary chest tubes can definitely cause harm
• We plan to randomize small and moderate sized
  OPTXs in the ICU to chest tube or observation
  this summer
• Clinicians should always treat the patient as
  they believe best, but chest tubes are not
  routinely recommended in the medical literature
• The Trauma Service will identify these patients
  but we will all have to understand what we are
  doing