The Occult Pneumothorax: Issue or Incidental?

AW Kirkpatrick CD MD FRCSC

Regional Medical Director of Trauma, The Region Formerly

known as “Calgary”

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

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 don’t 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

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

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

CXR

Learning Objective 1Define the term “Occult Pneumothorax”

• A PTX identified on an abdominal CT scan that was not seen on a preceding supine AP CXRCXR11

Wall SD, Am J Radiol 1983

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 19963Di Bartolemeo, J Trauma 2001

Management?

ATLS Recommendations

2008 Recommendations2008 Recommendations

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 2008Barrios et al, Am Surg 2008

Debate

Second Opinions from other Trauma Surgeons

Multi-Disciplinary Decision Making

Medical, Nursing, Respiratory Therapy

Anaesthesia Consultation

Internal Medicine Consultation

Back to the Books –Literature Search

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

PubMed Search: Occult Pneumothorax AND Mechanical

Ventilation LIMITED TO RCT’s

• 1 single study!!!• Enderson BL, Abdalla R, Frame SB, Casey Enderson BL, Abdalla R, Frame SB, Casey

MT, Gould H, Maull KI.MT, Gould H, Maull KI.Tube thoracostomy for occult pneumothorax: a Tube thoracostomy for occult pneumothorax: a prospective randomized study of its use.prospective randomized study of its use.J Trauma. 1993 Nov; 35(5): 726-9; discussion J Trauma. 1993 Nov; 35(5): 726-9; discussion 729-30. 729-30. PMID: 8230337 [PubMed - indexed for PMID: 8230337 [PubMed - indexed for MEDLINE] MEDLINE]

“Related Articles”

• Reveals a second study• Brasel KJ, Stafford RE, Weigelt JA, Brasel KJ, Stafford RE, Weigelt JA,

Tenquist JE, Borgstrom DC.Tenquist JE, Borgstrom DC. Treatment Treatment of occult pneumothoraces from blunt of occult pneumothoraces from blunt trauma.trauma.J Trauma. 1999 Jun; 46(6): 987-90; J Trauma. 1999 Jun; 46(6): 987-90; discussion 990-1. discussion 990-1. PMID: 10372613 [PubMed - indexed for PMID: 10372613 [PubMed - indexed for MEDLINE] MEDLINE]

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

Demographics

Only 27 patients ventilated

Positive Pressure Ventilation

15 ventilated with a 15 ventilated with a chest tubechest tube

12 ventilated without 12 ventilated without

a chest tubea chest tube

Complications - Enderson

• Significantly more major complications in the observed group (p<0.02)

• 8/15 (53%) patients on mechanical ventilation required a chest tube for PTX progression

• 3/15 (20%) developed tension PTXs

Conclusions – Enderson 1993

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

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 CenterSt John’s Regional Health Center

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

Demographics

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

Outcomes in the Mechanical Ventilation Group – Brasel 1999

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

• Chest tube placedChest tube placed– No emergent chestNo emergent chest– 4 had PTX progression 4 had PTX progression

related to coming off related to coming off suctionsuction

• Observed with no chest tubeObserved with no chest tube– 3 had PTX progression3 had PTX progression– 2 on PPV had chest tubes placed 2 on PPV had chest tubes placed

(33% of this group)(33% of this group)– Chest tubes also placed forChest tubes also placed for

• Retained hemothoraxRetained hemothorax• Increased pleural effusionIncreased pleural effusion• Asymptomatic PTX progressionAsymptomatic PTX progression• Spinal surgerySpinal surgery

Conclusions Brasel 1999

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

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

Building the CaseLiterature Review Can J Surg (2003) + (in press)Literature Review Can J Surg (2003) + (in press)

Epidemiology and Incidence (J Trauma 2005)Epidemiology and Incidence (J Trauma 2005)

Anatomic Distribution (Am J Surg 2005)Anatomic Distribution (Am J Surg 2005)

Diagnostic Errors (J Trauma 2006)Diagnostic Errors (J Trauma 2006)

Complications (Can J Surg 2007)Complications (Can J Surg 2007)

Randomized Pilot Data to Power the Definitive Trial Randomized Pilot Data to Power the Definitive Trial

(Am J Surg 2009)(Am J Surg 2009)

Literature Review

Ball CG et al., The Occult Ball CG et al., The Occult Pneumothorax: Pneumothorax: What Have we Learned from the What Have we Learned from the Recent Literature? Can J Surg (in Recent Literature? Can J Surg (in press) press) 20092009

Incidence

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 ventilatedtrauma patient, Canadian Journal of Surgery, 2003.

Management (including retrospective)

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

Occult Pneumothorax

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

Diagnostic Ultrasound &Occult Pneumothoraces

Lichtenstein 2005Lichtenstein 2005 357 hemithoraces357 hemithoraces Sens-95%, spec – 94%Sens-95%, spec – 94%

Blaivas 2005Blaivas 2005 176 patients176 patients Sens – 98.1%, spec – 99.2% Sens – 98.1%, spec – 99.2%

Needle Decompression of a tension pneumothorax

Kirkpatrick et al., J Trauma 2009Kirkpatrick et al., J Trauma 2009

Lung Sliding = Hearing Breathe Sounds

With Pneumothorax the Normal Signs are Gone

Lung Point Sign

Reproduced with permissionReproduced with permission

Lichtenstein, Critical Lichtenstein, Critical Care Medicine Care Medicine 2005;33:1231-12382005;33:1231-1238

The Calgary Experience:How 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 occultpneumothoraces in victims of major trauma, Journal of Trauma, 2005.

• PTX prospective incidence = 26% of 405 patients receiving a thoracoabdominal CT had a PTX

• 76% of these were considered occult by the treating physicians

The Prospective Calgary Experience – 4 yrs later

Ball CG, et al., Clinical predictors, Injury 2009

Where are they anatomically?

PTX DistributionOccult 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.

PTX Size

89 PTXs89 PTXs13 overt13 overt49 OPTX49 OPTX27 residual27 residual

Ball CG, Kirkpatrick et al., J Trauma 2005;59:917-925

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

Potential plain radiographic signs of an occult PTX

• Double diaphragm• Deep sulcus• Hyperlucent

hemithorax• Sharpened cardiac

silhouette• Depressed diaphragm• Apical pericardial fat

sign

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 occultor simply missed?, J Trauma 2006.

How Should They Be Managed?

OPTX

Ventilated Non-Ventilated

•Total (N)Total (N) 17 (35%)17 (35%) 32 (65%)32 (65%)•Median ISSMedian ISS 3434** 22.522.5**

•Received TTReceived TT 13 (13 (76%76%)) 10 (10 (31%31%))•Required TTRequired TT 1 / 4 (25%)1 / 4 (25%) 1 / 22 (5%)1 / 22 (5%)

After PTX ProgressionAfter PTX Progression

Ball CG, J Trauma 2005

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• PneumoniaEtoch Arch Surg 1995, Bailey Etoch Arch Surg 1995, Bailey

J Accid Emerg Med 2000J Accid Emerg Med 2000

Chest Tube Complications at FMC

•TotalTotal 22% (17/76)22% (17/76)•InsertionalInsertional

–Intercostal artery lacerationIntercostal artery laceration 24% (4/17)24% (4/17)–Intraparenchymal lung placementIntraparenchymal lung placement 12% (2/17)12% (2/17)

•PositionalPositional 53% (9/17)53% (9/17)•InfectiveInfective

–EmpyemaEmpyema 6% (1/17)6% (1/17)–Wound infectionWound infection 6% (1/17)6% (1/17)

Ball CG et al., are we training our residents?, Canadian Journal of Surgery, 2007;50:450-458.

(OPTICC) (OPTICC) Occult PneumoThorax In Occult PneumoThorax In

Critical Care TrialCritical Care Trial

Brain Injury & Trauma Research CommitteeDepartments of Critical Care Medicine &

SurgeryFoothills Medical Centre

Supported by Supported by

Canadian Trauma Trials Canadian Trauma Trials CollaborativeCollaborative

Canadian Intensive Care Canadian Intensive Care FoundationFoundation

OPTXs in the non-ventilated

• Stable – observe

• Recommended daily CXR

• Place a tube if• Becomes overt PTX• Any distress• Hemothorax

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 mediumSmall or medium

sizedsized

Exclude – Large OPTX

Mid-coronalMid-coronal

lineline

Large extendsLarge extends

posterior to this posterior to this

line line

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

Outcomes

1. Respiratory Distress2. Requirement for chest

tubes3. 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

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 2009Ouellet, Am J Surg 2009

Preliminary Results

• OPTICC Results– 9 chest tubes– 13 observed

• 4 required non-urgent chest tube

– Respiratory distress• 33% versus 46%

– Mortality• 22% versus 15%

Conclusions

• No observed difference in morbidity

• Study is practical and feasible

QuebecQuebec

CalgaryCalgary

Continuing Pilot Enrolment

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

- 12

Proposal to the Canadian Institute for Health Research

(CIHR)• Letters of Intent

– Vancouver (VGH)– Edmonton (University)– Toronto

(Sunnybrook, St.Mike’s)– London (University)– Sherbrooke – Montreal (McGill)

• Letters of Intent– Quebec (L’Enfant

Jesus)– Ottawa (Civic)– Calgary (FMC)– OF course, anyone

else that want to be involved

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

Learning Objectives

1. Define what is meant by the term occult pneumothorax

2. Define the epidemiology of occult pneumothoraces

3. Define the diagnostic strategies to detect occult pneumothoraces

4. Define the controversies in occult pneumothorax management

5. Define the risks involved in either treating or observing occult pneumothoraces

The real take-home!!

• Shouldn’t we be enrolling this patient?

D’oh Missed D’oh Missed

another patient!another patient!

Thank You

andrew.kirkpatrick@albertahealth

services.ca

OR

andrew.kirkpatrick@calgaryhealth

services.ca

Take-home

1.1. Pneumothoraces are very common and the right chest Pneumothoraces are very common and the right chest tube can save a lifetube can save a life

2.2. Half of all the PTXs we see are occult and we don’t Half of all the PTXs we see are occult and we don’t know what to do with themknow what to do with them

3.3. Unnecessary chest tubes can definitely cause harmUnnecessary chest tubes can definitely cause harm4.4. We plan to randomize small and moderate sized We plan to randomize small and moderate sized

OPTXs in the ICU to chest tube or observation this OPTXs in the ICU to chest tube or observation this summersummer

5.5. Clinicians should always treat the patient as they Clinicians should always treat the patient as they believe best, but chest tubes are not routinely believe best, but chest tubes are not routinely recommended in the medical literature recommended in the medical literature

6.6. The Trauma Service will identify these patients but we The Trauma Service will identify these patients but we will all have to understand what we are doingwill all have to understand what we are doing