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Three Part Question

In [patients with traumatic pneumothorax] does [insertion of an intercostal drain] reduce [complications, morbidity or mortality]?

Clinical Scenario

A 23 year old woman attends your department having been kicked in the chest by her horse. On arrival, she is haemodynamically stable and complaining of right sided chest pain. Your examination reveals an isolated chest injury. You arrange a portable chest xray which shows a small, right sided, apical pneumothorax. Her observations are all normal and she has no respiratory distress. You wonder whether you can avoid inserting a chest drain, and manage this patient conservatively.

Search Strategy

The Medline, Pubmed and EMBASE databases were searched via the Healthcare Databases Advanced Search interface. Search terms were as follows:

)("trauma* pneumothora*").ti,ab OR ("traumatic pneumothorax").ti,ab)) AND (("tube thoraco*").ti,ab OR ("chest tub*").ti,ab OR ("chest drai*").ti,ab OR ("conservative management").ti,ab)) AND (("morbidity").ti,ab OR ("mortality").ti,ab OR ("complication*").ti,ab))

Search Outcome

75 papers were found, of which 8 were potentially relevant. Full text versions of these 8 papers were reviewed by two independent researchers. 5 articles were deemed relevant for inclusion in this review. Of these 5 papers, 1 was a literature review with 4 observational studies.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Tebb, Z. et al. 2009 USA	Patients with simple traumatic pneumothorax	Literature review. 5 case series reviews and one prospective observational trial (Dural et al.) were reviewed.	Hegarty, M. 1976. 58 patients with pneumothorax less than 1.5cm or haemothorax.	8/58 required tube thoracostomy after initial conservative management. No in-hospital deaths.	Pneumothoraces and haemothoraces not separated. No definition of failure of conservative management. Long-term outcomes not evaluated. Retrospective. No definition of clinical deterioration. No follow up or complications described. Small study numbers, no specification of pneumothorax classification. Single centre study so results not generalisable No defined protocol for conservative management
			Knottenbelt & van der Spuy 1990. 333 patients managed with observation. PTX size less than 1.5cm.	33/333 (10%) required thoracostomy drainage.
			Bridges, K. et al. 1993. 35 patients with occult pneumothorax.	10/35 patients received immediate tube thoracostomy. 5/25 remaining patients (20%) required delayed chest drain for clinical deterioration.
			Johnson, G. 1996. 29 patients managed with observation.	2/29 (6%) underwent thoracostomy drainage for increasing pneumothorax size.
			Dural, K. et al. 2005. 108 patients with pneumothorax up to 20% in size.	46/108 (43%) required chest drain due to enlarging pneumothorax. By group, % undergoing tube thoracostomy: less 10% group: 25%; 10% group: 40%; 20% group: 69%.
			Barrios, C. et al. 2008. 51 patients with occult pneumothorax.	51/59 did not require tube thoracostomy. 16/20 receiving positive pressure ventilation required no chest drain.
Walker et al. 2018 UK	602 patients presenting with traumatic pneumothoraces to one UK Major Trauma Centre	Single centre, retrospective, observational study	Percentage of patients who underwent conservative management of traumatic pneumothorax.	46% (n=277). Patients treated conservatively had significantly smaller pneumothoraces than those undergoing immediate intervention (median 5.5mm v 22mm).	Single centre study so results may not be generalisable. Low rate of penetrating chest wall injury. Retrospective observational study so some data may be missing. Variation in initial imaging modality. High risk, unwell patients were likely under-represented in the conservative treatment arm. Inclusion criteria required a 3 day hospital stay or admittance to the high dependency unit; this likely provides bias against conservatively managed patients who are more likely to be discharged early. Hence the overall rate of effective conservative treatment is likely greater than observed. Patients receiving immediate intervention likely to have different baseline characteristics to the conservative arm with higher rates of: cardiorespiratory compromise, requirement for ventilation, surgical referral rates, mortality.
			Percentage of patients initially conservatively managed requiring subsequent thoracic intervention.	10% (n=25). 23 patients had chest drain insertion, 2 underwent surgery. Mean duration to intervention was 2.96 days.
			Median hospital length of stay.	10 days (non-conservative management) v 10 days (conservative management) p=0.35.
			Median ICU length of stay.	2 days (non-conservative management) v 0 days (conservative management) p= <0.001.
			Mortality.	11.1% (non-conservative management) v 7.2% (conservative management) p=0.1.
			Complications of chest tube insertion.	10%. (Drain re-sited 4.4%; subsequent drain after removal of first 2.4%; drain dislodged 1.2%; intraparenchymal drains 1.5%; empyema 0.6%; guidewire in pleural cavity 0.3%).
Saricam, M. et al. 2019 Turkey	78 patients with CT confirmed traumatic pneumothorax secondary to isolated blunt thoracic trauma	Single centre, retrospective, observational study	To compare treatment approaches (conservative v chest tube) in patients of varying traumatic pneumothorax size. Patients were split into 4 groups based on the size of pneumothorax on CT as a percentage of the pleural cavity: Group A 0-10% Group B 10-20% Group C 20-50% Group D more than 50%.	Group A (n =12) – 17% required chest drain due to increasing size of pneumothorax. All were initially treated conservatively. One patient developed recurrent pneumothorax at 10 days. Group B (n =18) – 44% required chest drain Group C (n= 22) – 55% required chest drain. Two patients developed recurrent pneumothorax at 10 days. Group D (n= 26) – 100% required chest drain. 12% of all patients with chest drains required a second tube thoracostomy for surgical emphysema, malposition of the initial tube, failure of lung re-expansion. Conclusion: Conservative management can be safely adopted for small traumatic pneumothoraces with a careful period of observation for deterioration over the following 24 hours.	Single centre study so results may not be generalisable. Retrospective observational study so some data may be missing. Small patient numbers. No statistical analysis. No formal comparison – chest drains in each group were inserted based on clinician discretion.
Eddine, S. et al. 2018 USA	336 adult patients presenting to a Level 1 Trauma Centre with chest wall injury, who had a CT chest at time of admission. Those with any evidence of haemothorax, chest tube insertion prior to admission and those mechanically ventilated were excluded.	Single-centre retrospective chart review	Patients were categorised in to two groups: largest air pocket of pneumothorax measuring more or less than 35mm from the parietal/visceral pleura to the mediastinum.	47 patients underwent immediate tube thoracostomy.	Patients requiring mechanical ventilation were excluded- these may represent a high risk group more likely to fail observation. 94.3% of injuries were caused by blunt trauma. The clinical course of penetrating chest injury may vary from that seen in blunt trauma. The decision to place an intercostal drain was left to individual clinician discretion. Retrospective, single centre study.
			Management of each case categorised in to immediate tube thoracostomy and observation (defined as no intervention within 4-hours).	272 patients had PTX less than or equal to 35mm: 247 (91%) successfully observed. 25 (9%) failed observation and required chest drain.
			Failure of observation defined as a need for delayed tube thoracostomy or secondary intervention.	17 patients had PTX greater than 35mm: 7 (41%) failed observation and required chest drain insertion secondary to radiological progression (37.5%), physiological deterioration or development of pleural effusion/haemothorax/ tension pneumothorax.
				Positive predictive value of predicting successful observation 35mm or less = 90.8%.
				Pneumothorax 35mm or less OR for predicting successful observation 0.142 (95%CI 0.047 – 0.428, p<0.001).
Kong V. et al. 2015 South Africa	125 patients sustaining stab wounds to the chest, who did not have immediate indication for chest drain, with a CXR confirmed small traumatic pneumothorax (<2cm at apex) All patients were managed conservatively, with close observation. Those with repeat CXRs at 12 hours showing worsening pneumothorax, or clinical deterioration, had chest drain insertion. Otherwise patients were discharged from hospital after 24 hours.	Single centre, retrospective, case-note review.	To determine whether small traumatic pneumothoraces <2cm be managed conservatively,	Of 125 patients, 4 (3%) required chest drain insertion: 1 – 1.5cm PTX = 1 1.5 – 2cm PTX = 3.	Retrospective case note review so not all required data may be available. Single centre study so results may not be generalisable. Small number of patients analysed with no statistical analysis.
				No subsequent readmissions, morbidity or mortality.
				Mean length of hospital stay 1.2 days.

Comment(s)

Our review compares the management of traumatic pneumothoraces with chest drain insertion or observation alone. Current guidance for the management of traumatic pneumothoraces from the American College of Surgeons Advanced Trauma Life Support recommends treatment with chest drain insertion for any traumatic pneumothorax. These guidelines include the recommendation that small, asymptomatic pneumothoraces can be managed with observation and aspiration, but this is at the clinician’s discretion and no further guidance is given in this regard. This review provides evidence that patients with small traumatic pneumothoraces can be managed conservatively without affecting morbidity, mortality or complications. Tebb et al.’s review assessed studies where patients were initially treated with conservative management for their traumatic pneumothoraces. Two papers demonstrated low complication rates for pneumothoraces less than 1.5cm in size when managed conservatively, with the need for subsequent chest drains in 10-13% of patients. In patients with occult pneumothoraces, 14-20% of patients failed conservative management due to clinical deterioration. Similar results were found by Johnson, where only 6% of patients observed required subsequent tube thoracostomy. Dural et al. demonstrated that with increasing size of pneumothorax there is higher chance of patients failing conservative treatment; 25% of patients with a pneumothorax <10% in size required chest drains compared to 69% in the 20% size group. Kong et al. added further evidence that traumatic pneumothoraces smaller than 1.5cm can be managed conservatively, with only 1/105 such patients requiring tube thoracostomy following initial conservative treatment. No patients they observed required readmission, nor suffered any morbidity or mortality. Similar to Dural et al., Saricam et al. classified the size of pneumothorax as a percentage of the thoracic cavity affected. In the group with pneumothoraces less than 10% in size, 17% of patients required a chest drain having been initially conservatively managed due to increasing size of pneumothorax. With increasing size of pneumothorax there was an increased chance of the requirement for tube thoracostomy: in patients with a pneumothorax 20-50% in size, 55% required chest drains. Overall, complication rates for chest drains were low, with 12% requiring a second chest drain insertion. Eddine et al. classified pneumothorax size as 35mm or less or greater than 35mm as measured on thoracic CT. They demonstrated that patients with a pneumothorax of 35mm or less can be safely managed with observation alone; only 9% of these patients failed conservative treatment, compared to 41% in the greater than 35mm group. Walker et al.’s study of 277 patients treated with observation for traumatic pneumothorax demonstrated only a 10% failure rate. Although hospital length of stay was the same for those treated with immediate tube thoracostomy, both ICU length of stay and mortality were significantly reduced in the observation group. This may reflect the smaller size of pneumothorax and likely smaller burden of disease in those treated with initial observation, but demonstrates at worst a non-inferior effect of conservative management. Complication rates for chest drain insertion found in this review range from 10-12% (Saricam et al. & Walker et al.). The reported rate for complications related to tube thoracostomy consistently ranges from 20-40% (Bailey 2000 & Hernandez et al. 2017). Such complications can be categorised in to: insertional, positional, removal, post-removal, equipment and educational related complications. Many complications are minor, such as skin infections, but more major complications such as visceral damage and pleural infection can be the source of morbidity and mortality for patients undergoing chest drain insertion. In all of the studies analysed, patients in the conservative treatment group were observed for signs of deterioration. Absolute definitions of ‘deterioration’ varied between each study, but parameters for deterioration can be classified as clinical or radiological. Clinical parameters of deterioration included: respiratory distress (O2 saturation less than 94%, requirement for supplemental oxygen, respiratory rate less than 8 per minute or more than 30 per minute); haemodynamic instability; reduced consciousness level. Radiological deterioration was defined as: increasing size of pneumothorax; tension pneumothorax; haemothorax; pleural effusion. Any patient who deteriorated underwent chest tube thoracostomy. All observed patients were admitted to hospital for at least 24 hours. In all five studies, patients underwent repeated chest x-ray at the 12 hour point from admission. If there were no signs of clinical or radiological deterioration patients were discharged home. Saricam et al. report 3/78 patients developed recurrent pneumothorax on repeat CXR at 10 days, with no clinical signs of pneumothorax. No other studies reported further morbidity, mortality or complications, but Tebb et al. recommend follow up for all patients. It can be seen that chest drain insertion is not a benign process in itself, with up to 40% of patients experiencing some form of chest drain related complications. Patients with large pneumothoraces or clinical signs of respiratory or haemodynamic compromise require immediate tube thoracostomy, as the benefits outweigh the risks. This review demonstrates that patients with small traumatic pneumothoraces and no respiratory distress can be safely managed with observation alone, with failure of conservative management occurring in a maximum of 20% of patients. All patients with traumatic pneumothoraces should be admitted to observe for signs of clinical or radiological deterioration. If these do not occur, patients can be discharged without intervention for outpatient follow up.

Clinical Bottom Line

Patients attending with a traumatic pneumothorax less than 1.5cm on chest x-ray or less than 10% thoracic volume on CT can be managed with conservative treatment without affecting morbidity, mortality or complications. All patients should be observed for at least 24 hours post-injury for signs of clinical or radiological deterioration. Should these occur, chest drain insertion should be considered. Patients discharged without intervention should undergo outpatient follow up.

References

1. Tebb, Z. et al. An argument for the conservative management of small traumatic pneumothoraces in populations with high prevalence of HIV and tuberculosis: an evidence-based review of the literature. . International Journal of Emergency Medicine 2009; pp. 75-79
2. Walker et al. Conservative Management in Traumatic Pneumothoraces: An Observational Study. Chest 2018; pp. 946-953.
3. Saricam, M. et al. Management of traumatic pneumothorax in isolated blunt chest trauma. The European Research Journal 2019; pp. 306-310
4. Eddine, S. et al. Observing pneumothoraces: The 35-millimeter rule is safe for both blunt and penetrating chest trauma. Journal of Trauma and Acute Care Surgery. 2019; pp. 557- 564.
5. Kong, V. et al. The selective conservative management of small traumatic pneumothoraces following stab injuries is safe: experience from a high-volume trauma in South Africa. European Journal of Emergency Surgery 2015; pp. 75-79.