Traumatic occult pneumothorax--a UK perspective

Conservative management of occult pneumothorax in mechanically ventilated patients: A systematic review and meta-analysis

BACKGROUND

The aim of this systematic review was to investigate the safety and effectiveness of conservative management versus prophylactic intercostal catheter (ICC) insertion for the management of occult pneumothoraces in mechanically ventilated patients.

METHODS

PubMed, Embase, CINAHL, Web of Science, Cochrane Central, and other trial registries were searched. Eligible studies were critically appraised using standardized instruments. Meta-analysis was performed with mixed-methods logistic regression where appropriate and sensitivity analyses were performed with alternative statistical methods (Stata™ 15 or RevMan 5.3) or summarized in narrative. Randomized controlled trials (RCTs) and cohort studies were analyzed separately.

RESULTS

Twelve studies with a total of 354 participants were included; three RCTs (178 participants) and nine cohort studies (176 participants). The majority of the included studies, particularly the cohort studies, were well conducted. Two of the RCTs were rated as low quality. Statistically significant differences were observed in the RCT analysis: ICC insertion (any reason) (odds ratio, 2.86; 95% confidence interval, 1.26-6.43, 2 RCTs) in favor of prophylactic ICC; ICC complications (odds ratio, 0.12; 95% confidence interval, 0.02-0.62, 2 RCTs) in favor of conservative management. Nonstatistically significant differences were observed for progression of pneumothorax, ICC insertion (progression to simple pneumothorax), and ICC insertion (nonpneumothorax reasons). Results of analyses showed high imprecision (wide confidence limits). Conservative management showed a low rate of tension pneumothorax (2.8%). Complications were higher in the ICC group (19.5% vs. 5.8%).

CONCLUSION

Available evidence suggests that conservative management is safe for the management of occult pneumothoraces in mechanically ventilated patients, especially when undergoing short-term (<4 days) ventilation. We recommend that patients undergoing mechanical ventilation for a procedure alone and patients suspected to be ventilated less than 4 days can be conservatively managed.

LEVEL OF EVIDENCE

Systematic review and meta-analysis, level III.

Effectiveness and safety of conservative management of occult pneumothorax in mechanically ventilated patients: a systematic review protocol

OBJECTIVE

This systematic review aims to synthesize the available evidence investigating the effectiveness and safety of conservative management of occult pneumothorax in mechanically ventilated patients.

INTRODUCTION

Occult pneumothorax is air within the pleural cavity that is diagnosed on a CT scan but was not suspected on the basis of preceding clinical examination or supine chest x-ray. Currently, there is no consensus on how to manage occult pneumothoraces, especially in patients requiring mechanical ventilation. It is common practice to place a prophylactic intercostal catheter to stop the potential development of a tension pneumothorax; however, there is a 20% risk of major complications from the intercostal catheter insertion. Recent evidence suggests that occult pneumothorax in mechanically ventilated patients can be managed conservatively, rather than using a prophylactic intercostal catheter as first-line management.

INCLUSION CRITERIA

This review will include studies investigating stable patients of all ages who were diagnosed with traumatic occult pneumothorax via CT scan, received mechanical ventilation, and underwent either conservative management or intercostal catheter insertion.

METHODS

Eligible studies will include randomized and non-randomized controlled trials, and prospective and retrospective cohort studies. PubMed, Embase, CINAHL, Web of Science, and Cochrane Central Register of Controlled Trials will be searched. International Clinical Trials Registry, Australian New Zealand Clinical Trials Registry, and ClinicalTrials.gov will be searched for unpublished studies. All included studies will be critically appraised using standardized JBI tools, with no exclusions based on methodological quality. Studies will, where possible, be pooled in statistical meta-analysis, with impact of methodological quality to be explored through sensitivity analysis.

Occult pneumothoraces – red flag or red herring?

Pneumothorax is a relatively common complication following blunt chest trauma; however, the investigation and management of these injuries remains a contentious issue. Occult pneumothoraces are those not diagnosed by conventional radiographic imaging, but by subsequent computed tomography. This review examines the current evidence base behind the investigation and management of this condition. An anteroposterior chest x-ray should not be underestimated in its ability to provide sufficient radiological information to instigate an initial management plan in the trauma setting. Ultrasound has a high diagnostic rate for pneumothoraces; however, it is subjected to influence from other injuries, whilst failing to address other important injuries in trauma patients requiring computed tomography imaging. It is therefore best used in situations where computed tomography is unavailable or contraindicated. In the management of occult pneumothoraces, there is little difference in patient outcome between those managed conservatively or with a prophylactic chest drain. Clinicians must be wary of recommendations which in this area are often based on inadequate study size and they should continue to provide the best individual care on a case-by-case basis. Observation alone in patients that are haemodynamically stable can be considered, with a view to drainage of the pneumothorax should the clinical status of the patient deteriorate.