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• Authors response
  Simon Leigh-Smith
  Published on: 29 April 2016
• Tension pneumothorax - time for a re-think?
  Plutarco E Chiquito-Lopez
  Published on: 29 April 2016
• Authors' reply
  Simon Leigh-Smith
  Published on: 29 April 2016
• Tension Pneumothorax - does it really occur that often?
  Timothy C Hardcastle
  Published on: 29 April 2016

• Published on: 29 April 2016

  Authors response

  • Simon Leigh-Smith, Emergency Medicine Physician
  • Other Contributors:
    • Tim Harris

  Dear Editor,

  We welcome the recent comments from Dr Chiquito-Lopez but despite the difficulty in correctly diagnosing this condition we would re-iterate our belief that needle thoracocentesis is sometimes performed indiscriminately and its use should be limited – a view shared by other authors.[1-5] The decision relating to whether or not to immediately decompress a suspected tension pneumothorax depends on whether...

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  Dear Editor,

  We welcome the recent comments from Dr Chiquito-Lopez but despite the difficulty in correctly diagnosing this condition we would re-iterate our belief that needle thoracocentesis is sometimes performed indiscriminately and its use should be limited – a view shared by other authors.[1-5] The decision relating to whether or not to immediately decompress a suspected tension pneumothorax depends on whether the patient is still compensating (more likely if spontaneously ventilating than if ventilated) and the only absolute indication is decompensation. We would stress that an awake, tachypnoeic, normotensive patient is still compensating. Box 7 of our review along with the sections on needle thoracocentesis and tube thoracostomy in the article main text and summary provide further discussion on this.[6]

  We are firm advocates of taking an immediate CXR in all spontaneously ventilating patients who may have a tension pneumothorax but who are compensating. We agree that the concept of "the chest radiograph that should never have been taken" has encouraged unnecessary blind treatment of patients who may still be compensating well and many of whom may not even have a pneumothorax.

  A fuller review of the complications of tube thoracostomy was not possible given the constraints of the article. We therefore gave similar references to those cited by Dr Chiquito-Lopez as well as mentioning the important complications in the section on tube thoracostomy in the article along with box 10.

  References

  1. Trauma.org. Needle Decompression - discussion forum. http://www.trauma.org/archives/ncdeco.html 1997:(accessed apr 2004).

  2. Trauma.org. Needle Thoracostomy - discussion forum. http://www.trauma.org/archives/needlethoracostomy.html 2003;8(2):(accessed apr 2004).

  3. Cullinane DC, Morris JA, Jr., Bass JG, Rutherford EJ. Needle thoracostomy may not be indicated in the trauma patient. Injury 2001;32(10):749-52.

  4. Etoch SW, Bar-Natan MF, Miller FB, et al. Tube thoracostomy. Factors related to complications. Arch Surg 1995;130:521–5, 525–6.

  5. Bjerke H. Tension pneumothorax. Emedicine Specialities, 2002. (http://www.emedicine.com/med/topic2793.htm).

  6. S Leigh-Smith, Harris T. Tension pneumothorax-time for a re-think? Emerg Med J 2005; 22 (1): 8-16.

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  Conflict of Interest:
  None declared.

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• Published on: 29 April 2016

  Tension pneumothorax - time for a re-think?

  • Plutarco E Chiquito-Lopez, Emergency Medicine Consultant

  Dear Editor,

  I have two comments to make to the interesting and stimulating article by S Leigh-Smith and T Harris on tension pneumothorax.[1]

  1. The number of needle thoracocentesis far exceeds the incidence of tension pneumothorax because it can be difficult to distinguish this condition from a large or even moderate size pneumothorax presenting with rapid respiratory or haemodynamic deterioration in pati...

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  Dear Editor,

  I have two comments to make to the interesting and stimulating article by S Leigh-Smith and T Harris on tension pneumothorax.[1]

  1. The number of needle thoracocentesis far exceeds the incidence of tension pneumothorax because it can be difficult to distinguish this condition from a large or even moderate size pneumothorax presenting with rapid respiratory or haemodynamic deterioration in patients with poor cardio-respiratory reserve. The concept of: "the chest radiograph that should never have been taken" may also play a role, as it encourages urgent decompression before the diagnosis is confirmed, even in patients that could have tolerated a short delay and benefited from the chest x-ray. However, this is not an easy decision to make and most would err on the side of caution.

  2. Recognized complications associated with the procedure of tube thoracostomy were omitted. Tube blockages, kinks and inadequate positioning within the pleural cavity can cause tube malfunction, which is associated with incomplete evacuation of collections and poor lung re-expansion, variables that predispose to empyema, clotted haemothorax and lung entrapment.[2,3] Non therapeutic tube insertions [4], accidental removals of the tube and excessive pain during the procedure are also significant complications.

  References

  1. S Leigh-Smith, Harris T. Tension pneumothorax-time for a re-think? Emerg Med J 2005; 22 (1): 8-16.

  2. Millikan JS, Moore EE, Steiner E, et al. Complications of tube thoracostomy in acute trauma. Am J Surg 1980; 140: 738-741.

  3. Fallon WF. Post-traumatic empyema. J Am Coll Surg 1994; 179: 483- 491.

  4. Schmidt U, Stalp M, Gerich T, et al. Chest tube decompression of Blunt chest injuries by Physicians in the Field: Effectiveness and Complications. J Trauma 1998: 44 (1): 98-101.

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  Conflict of Interest:
  None declared.

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• Published on: 29 April 2016

  Authors' reply

  • Simon Leigh-Smith, ED SpR
  • Other Contributors:
    • Tim Harris

  Dear Editor,

  We are grateful for your comments on our recent review of tension pneumothorax (TPT) and it is especially useful to have the opinion of someone with as much clinical experience of the condition as yourself. We do not have all the answers and have attempted to highlight some of the difficulties involved in the present understanding of this condition – hence the title of the review; "...time for a re...

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  Dear Editor,

  We are grateful for your comments on our recent review of tension pneumothorax (TPT) and it is especially useful to have the opinion of someone with as much clinical experience of the condition as yourself. We do not have all the answers and have attempted to highlight some of the difficulties involved in the present understanding of this condition – hence the title of the review; "...time for a re-think"! From a thorough review of the literature we certainly feel that there has been inappropriate extrapolation of evidence between different patient populations leading to a need to question the accepted dogma.

  Referring to the incidence of the condition and whether it is a “tension” or “large” pneumothorax: With any pneumothorax until the pleural defect has healed the size of the pneumothorax will be a balance between the rate at which it is accumulating and the rate at which it is being absorbed. Apart from case’s where there is a large pleural defect and these two processes are in perfect balance all other pneumothoraces will be either expanding or resolving.

  Expanding pneumothoraces clearly have the potential to continue this process until they cause clinical compromise followed by decompensation and eventual death – but this would appear to be a very rare occurrence. It is however possible that there is a sub-clinical expanding phase in a large number of the pneumothoraces that we presently call “simple” and some of these may even have transiently positive intra-pleural pressure (IPP). Whether this is the case will remain un-answered until the IPP is measured in a large series of patients with pneumothorax – a study we hope to perform. Correlation between IPPs and the patients natural history may help in the risk management of patients with pneumothorax – specifically the questions of whether to aspirate, drain or simply observe patients with a pneumothorax.

  The definition of a tension pneumothorax (TPT) depends on where in it’s natural history we define it. The spectrum encompasses: transiently positive IPP, clinically compensated compromise, decompensation and finally pre-terminal. The haemodynamic compromise definition used by ATLS and DSTC is a practical one that highlights the low risk-benefit ratio of draining a possible TPT in a hypotensive patient thus potentially saving a life; a recommendation with which we agree. This is defining TPT at a point after decompensation and may be acceptable for ventilated patients. However, one of the strongest recommendations in our article was (and still is) that TPT should be considered in two groups - spontaneously ventilating (SV) and mechanically ventilated patients – as it has a different natural history and clinical presentation in these two groups.

  Hypotension is one of the most reliable signs in ventilated patients but is rare in SV patients. This is supported by the SV animal studies and SV human case reports (of which we now have 29 rather than the 18 cited in the original article). SV patients will manifest severe hypoxia and in many cases respiratory arrest before haemodynamic compromise occurs. Hence in SV patient’s haemodynamic compromise lacks sensitivity and (particularly in trauma) also lacks specificity. Clearly therefore a definition is needed at an earlier stage in the conditions development in SV patients which is why we suggest a clinical definition of: “...‘significant respiratory or haemodynamic compromise (the latter especially in ventilated patients) that reverses on decompression alone’—that is, without chest drain placement.”

  The 18 patients included in box 3. had rigid inclusion criteria applied to them – that we should have mentioned in the article – i.e. only case reports where a significant clinical improvement (SpO2, HR, RR, BP) or a persistent outwards hiss of air occurred following decompression alone. We therefore consider them to be in keeping with our definition of a clinical TPT and the data from them to be valid. From these (and the further 11 SV case reports subsequently identified) both tracheal deviation and raised JVP are very rare findings.

  Since this article was written we have also seen at least 4 patients with medical and traumatic TPT’s who manifested extreme respiratory distress, markedly deviated mediastinum on CXR and persistent outwards hiss of air on thoracostomy but all of whom had central trachea and flat neck veins – despite persistent checking. With a 50:50 odds ratio of correctly identifying tracheal deviation anyway we must further question it’s usefulness but would be interested to know how much use your team finds both these signs. We plan to do a case series of the clinical signs in SV patients and hope you will enter the eligible ones of your own into it.

  We thank you for your useful comments on arterial embolism and freely acknowledge this should have been mentioned. However, we question the incidence of 1%.

  The frequency with which TPT is diagnosed in ventilated patients is probably appropriate. Both of us however have experience in SV patients of TPT being over-diagnosed/over-treated in markedly hypotensive patients who are only mildly breathless whilst being under-diagnosed in severely breathless normotensive patients – especially if the examining clinician interprets that their trachea is central and the neck veins are flat. We hope to re-dress this balance by emphasizing the importance of a thorough visual thoracic examination and erasing the assumption that a central trachea has a 100% negative predictive value.

  We certainly do not wish to contribute to the present indiscriminate use of needle thoracocentesis and hope that this trend will be reversed. Instead we hope that more accurate consideration of the diagnostic symptoms/signs (particularly in the pre- hospital environment) and in hospital the immediate use of CXR - for dyspnoeic patients in whom pneumothorax is a possibility – will limit decompression to those who really need it. We would also like to see tube thoracostomy as the primary treatment in the majority of cases once the diagnosis is suspected for valid clinical or radiological reasons.

  With thanks again for your interest and comments.

  Simon & Tim

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  Conflict of Interest:
  None declared.

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• Published on: 29 April 2016

  Tension Pneumothorax - does it really occur that often?

  • Timothy C Hardcastle, Trauma Surgeon

  Dear Editor,

  I write regarding the review published in the EMJ [1], a photocopy of which was presented to me by a student paramedic to comment on. I take this opportunity to submit a rapid response.

  You correctly state that the definition of Tension Pneumothorax is difficult to pin down early in your article and that the various definitions contain combinations of various criteria. With this I concur....

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  Dear Editor,

  I write regarding the review published in the EMJ [1], a photocopy of which was presented to me by a student paramedic to comment on. I take this opportunity to submit a rapid response.

  You correctly state that the definition of Tension Pneumothorax is difficult to pin down early in your article and that the various definitions contain combinations of various criteria. With this I concur. International ATLS and DSTC consensus currently still require the following: (Commenting on Box 1)

  1) Haemodynamic comprimise.
  2) Evidence of mediastinal compression - not necessarily SHIFT of trachea, since the effect of air under pressure is to expand, thus exerting more expansile pressure that liquid.
  3) Cardiac inability to fill due to this relative compression - which then leads to a raised JVP, which may not necessarily distend the neck veins, but this usually occurs.

  The question must, therefore, be posed as to whether the "other" cases of TPT in the human studies such as the London pre-hospital study, were not just large PT's rather than true TPT's - this remains the contention of such people as the great Ken Mattox, which implies they should be managed with chest drain rather than needle. Thus, it must also be questioned if the clinical details summarised in Box 3 can truly be said to reflect the real incidence in true TPT.

  I therefore have to take issue with your recommendation in the summary to "de-emphasise" tracheal deviation and venous engorgement, since I feel this will lead to an increased incidence of over-diagnosis of a condition which is already probably over-diagnosed. Rather, it should be emphasised so as to discriminate a large pneumothorax from a tension pneumothorax.

  You also fail to include the complication in your Box 10 which is specifically said to be related to NEEDLE decompression, namely arterial air embolism, in patients who do not actually have a TPT (1% incidence according to Mattox in his textbook TRAUMA [2]).

  From personal experience, running a trauma unit in South Africa, where we see 800 - 900 simple PT or HT patients annually and another 400 - 500 with additional injuries, I can say that we consider less than 1% of them to have had a TPT, both clinically (or on history if decompressed by EMS paramedics) and NO fatalities have occurred by waiting for the conventional tube chest drain rather than doing needle decompression in the majority, indeed we (in-hospital) have only "needled" two chests in the last three years!

  I would concur that true TPT is more common in the ventilated trauma patient, particularly with rib fractures and we have a policy of ipsilateral or bilarteral prophylactic chest drains in all major rib fracture patients, particularly if they have a co-existent lung contusion.

  I thank you for considering these comments.

  Kind regards

  Tim

  Dr T C Hardcastle, M.B.,Ch.B.(Stell); M.Med(Chir); FCS(SA), General Surgeon (Trauma and ICU)

  ATLS and DSTC instructor, Intern program Coordinator: Surgery, Program Manager: Emergency Medicine (U.S.), Operational Head: Diana Princess of Wales Trauma Unit

  Department of Surgery Room 4064, Tygerberg Hospital / University of Stellenbosch, PO Box 19063, Tygerberg 7505, Western Cape, South Africa

  2 Lorient Close
  Vredekloof, Brackenfell
  7560, Western Cape
  South Africa

  e-mail: tch@sun.ac.za

  References

  1. Leigh-Smith, Harris: Tension Pneumothorax - time for a rethink? EMJ 2005;22:8-16.

  2. Pneumothorax and systemic air embolism during positive-pressure ventilation. Anesthesiology.1999 May;90(5):1479-81.

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  Conflict of Interest:
  None declared.

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