CT detection of occult pneumothorax in head trauma

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Clinical Trials Registry, Australian New Zealand Clinical Trials Registry, and ClinicalTrials.gov will be searched for unpublished studies.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.

Observing pneumothoraces: The 35-millimeter rule is safe for both blunt and penetrating chest trauma

BACKGROUND

As more pneumothoraxes (PTX) are being identified on chest computed tomography (CT), the empiric trigger for tube thoracostomy (TT) versus observation remains unclear. We hypothesized that PTX measuring 35 mm or less on chest CT can be safely observed in both penetrating and blunt trauma mechanisms.

METHODS

A retrospective review was conducted of all patients diagnosed with PTX by chest CT between January 2011 and December 2016. Patients were excluded if they had an associated hemothorax, an immediate TT (TT placed before the initial chest CT), or if they were on mechanical ventilation. Size of PTX was quantified by measuring the radial distance between the parietal and visceral pleura/mediastinum in a line perpendicular to the chest wall on axial imaging of the largest air pocket. Based on previous work, a cutoff of 35 mm on the initial CT was used to dichotomize the groups. Failure of observation was defined as the need for a delayed TT during the first week. A univariate analysis was performed to identify predictors of failure in both groups, and multivariate analysis was constructed to assess the independent impact of PTX measurement on the failure of observation while controlling for demographics and chest injuries.

RESULTS

Of the 1,767 chest trauma patients screened, 832 (47%) had PTX, and of those meeting inclusion criteria, 257 (89.0%) were successfully observed until discharge. Of those successfully observed, 247 (96%) patients had a measurement of 35 mm or less. The positive predictive value for 35 mm as a cutoff was 90.8% to predict successful observation. In the univariant analyses, rib fractures (p = 0.048), Glasgow Coma Scale (p = 0.012), and size of the PTX (≤35 mm or >35 mm) (P < 0.0001) were associated with failed observation. In multivariate analysis, PTX measuring 35 mm or less was an independent predictor of successful observation (odds ratio, 0.142; 95% confidence interval, 0.047-0.428)] for the combined blunt and penetrating trauma patients.

CONCLUSION

A 35-mm cutoff is safe as a general guide with only 9% of stable patients failing initial observation regardless of mechanism.

LEVEL OF EVIDENCE

Therapeutic, level III.

Factors Associated with Chest Tube Placement in Blunt Trauma Patients with an Occult Pneumothorax

Background

An occult pneumothorax is identified by computed tomography but not visualized by a plain film chest X-ray. The optimal management remains unclear.

Methods

A retrospective review of an urban level I trauma center's trauma registry was conducted to identify patients with occult pneumothorax over a 2-year period. Factors predictive of chest tube placement were identified using univariate and multivariate logistic regression analysis.

Results

A total of 131 patients were identified, of whom 100 were managed expectantly with an initial period of observation. Ultimately, 42 (32.0%) patients received chest tubes and 89 did not. The patients who received chest tubes had larger pneumothoraces at initial assessment, a higher incidence of rib fractures, and an increased average number of rib fractures, of which significantly more were displaced.

Conclusions

Displaced rib fractures and moderate-sized pneumothoraces are significant factors associated with chest tube placement in a victim of blunt trauma with occult pneumothorax. The optimal timing for the first follow-up chest X-ray remains unclear.

Does the Addition of M-Mode to B-Mode Ultrasound Increase the Accuracy of Identification of Lung Sliding in Traumatic Pneumothoraces?

OBJECTIVES

It is unknown whether the addition of M-mode to B-mode ultrasound (US) has any effect on the overall accuracy of interpretation of lung sliding in the evaluation of a pneumothorax by emergency physicians. This study aimed to determine what effect, if any, this addition has on US interpretation by emergency physicians of varying training levels.

METHODS

One hundred forty emergency physicians were randomized via online software to receive a quiz with B-mode clips alone or B-mode with corresponding M-mode images and asked to identify the presence or absence of lung sliding.

RESULTS

The sensitivity, specificity, and accuracy of the diagnosis of lung sliding with and without M-mode US were compared. Overall, the sensitivities, specificities, and accuracies of B-mode + M-mode US versus B-mode US alone were 93.1% and 93.2% (P = .8), 96.0% and 89.8% (P < .0001), and 91.5% and 94.5% (P = .0091), respectively. A subgroup analysis showed that in those providers with fewer than 250 total US scans done previously, M-mode US increased accuracy from 88.2% (95% confidence interval, 86.2%-90.2%) to 94.4% (92.8%-96.0%; P = .001) and increased the specificity from 87.0% (84.5%-89.5%) to 97.2% (95.4%-99.0%; P < .0001) compared with B-mode US alone. There was no statistically significant difference observed in the sensitivity, specificity, and accuracy of B-mode + M-mode US compared with B-mode US alone in those with more than 250 scans.

CONCLUSIONS

The addition of M-mode images to B-mode clips aids in the accurate diagnosis of lung sliding by emergency physicians. The subgroup analysis showed that the benefit of M-mode US disappears after emergency physicians have performed more than 250 US examinations.

Impact of donor chest radiography on clinical outcome after lung transplantation

Background

Organ donation guidelines recommend a “clear” conventional bedside chest radiograph before lung transplantation despite only moderate accuracy for cardiopulmonary abnormalities.

Purpose

To evaluate the influence of donor image interpretation on lung transplantation outcome in recipients by following early and late complications, one-year survival, and to correlate imaging findings and blood gas analysis with lung transplantation outcome in recipients.

Material and Methods

In 35 lung donors from a single institution clinical reports and study reviews of imaging findings of the mandatory bedside chest radiographs and blood gas analyses were compared with clinical outcome in 38 recipients. Hospitalization time, peri- and postoperative complications, early complications (primary graft dysfunction, infection), 30-day and one-year survival, and forced expiratory volume in 1 s percentage of predicted normal value (FEV1%) at one-year follow-up were analyzed.

Results

Findings in clinical reports and study reviews differed substantially, e.g. regarding reported decompensation, edema, infection, and atelectasis. No correlation was shown between imaging findings in clinical report or study review and blood gas analyses in the lung donors compared to postoperative outcome in recipients.

Conclusion

The interpretation of the mandatory chest radiograph in its present form does not influence one-year outcome in lung transplantation. Larger imaging studies or a change in clinical routine including computed tomography may provide evidence for future guidelines.

CT and Chest Radiography in the Evaluation of Adult Respiratory Distress Syndrome

CT is seldom employed in adult respiratory distress syndrome (ARDS), mostly due to problems in transporting and monitoring these severely ill patients. We reviewed the findings of 74 ARDS patients who underwent chest CT. Lung opacities were bilateral in almost all patients and dependent in most cases (86%). The opacities were patchy (42%), homogeneous (23%), ground glass (8%) or mixed (27%). Opacities prevailed in basal regions (68%) compared to hilar and apical ones. Air bronchograms were frequently seen in areas of consolidation (89%). In contrast with previous reports, pleural effusion was a frequent finding (50%) that did not worsen prognosis. Often loculated pneumothorax (32%) was mostly anteromedial. Ineffective position of thoracostomy tubes was detected at CT in 13/20 patients. Pulmonary air cysts (30%>), always multiple and mostly bilateral, were associated with a higher mortality (55%) than that of the whole study group (35%). Compared to chest radiographs, CT often yielded additional information (66%), with direct influence on patient treatment in 22% of cases.

Diagnostic accuracy of oblique chest radiograph for occult pneumothorax: comparison with ultrasonography

Backgraound

An occult pneumothorax is a pneumothorax that is not seen on a supine chest X-ray but is detected by computed tomography scanning. However, critical patients are difficult to transport to the computed tomography suite. We previously reported a method to detect occult pneumothorax using oblique chest radiography (OXR). Several authors have also reported that ultrasonography is an effective technique for detecting occult pneumothorax. The aim of this study was to evaluate the usefulness of OXR in the diagnosis of the occult pneumothorax and to compare OXR with ultrasonography.

Methods

All consecutive blunt chest trauma patients with clinically suspected pneumothorax on arrival at the emergency department were prospectively included at our tertiary-care center. The patients underwent OXR and ultrasonography, and underwent computed tomography scans as the gold standard. Occult pneumothorax size on computed tomography was classified as minuscule, anterior, or anterolateral.

Results

One hundred and fifty-nine patients were enrolled. Of the 70 occult pneumothoraces found in the 318 thoraces, 19 were minuscule, 32 were anterior, and 19 were anterolateral. The sensitivity and specificity of OXR for detecting occult pneumothorax was 61.4 % and 99.2 %, respectively. The sensitivity and specificity of lung ultrasonography was 62.9 % and 98.8 %, respectively. Among 27 occult pneumothoraces that could not be detected by OXR, 16 were minuscule and 21 could be conservatively managed without thoracostomy.

Conclusion

OXR appears to be as good method as lung ultrasonography in the detection of large occult pneumothorax. In trauma patients who are difficult to transfer to computed tomography scan, OXR may be effective at detecting occult pneumothorax with a risk of progression.

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.

ERS task force statement: diagnosis and treatment of primary spontaneous pneumothorax

Primary spontaneous pneumothorax (PSP) affects young healthy people with a significant recurrence rate. Recent advances in treatment have been variably implemented in clinical practice. This statement reviews the latest developments and concepts to improve clinical management and stimulate further research.The European Respiratory Society's Scientific Committee established a multidisciplinary team of pulmonologists and surgeons to produce a comprehensive review of available scientific evidence.Smoking remains the main risk factor of PSP. Routine smoking cessation is advised. More prospective data are required to better define the PSP population and incidence of recurrence. In first episodes of PSP, treatment approach is driven by symptoms rather than PSP size. The role of bullae rupture as the cause of air leakage remains unclear, implying that any treatment of PSP recurrence includes pleurodesis. Talc poudrage pleurodesis by thoracoscopy is safe, provided calibrated talc is available. Video-assisted thoracic surgery is preferred to thoracotomy as a surgical approach.In first episodes of PSP, aspiration is required only in symptomatic patients. After a persistent or recurrent PSP, definitive treatment including pleurodesis is undertaken. Future randomised controlled trials comparing different strategies are required.

Prevalence of large and occult pneumothoraces in patients with severe blunt trauma upon hospital admission: experience of 526 cases in a French level 1 trauma center

BACKGROUND

Occult pneumothoraces (PTXs), which are not visible on chest x-ray, may progress to tension PTX. The aim of study was to establish the prevalence of large occult PTXs upon admission of patients with severe blunt trauma, according to prehospital mechanical ventilation.

METHODS

Patients with severe trauma consecutively admitted to our institution for 5 years were retrospectively analyzed. All patients with blunt thoracic trauma who had undergone computed tomographic (CT) within the first hour of hospitalization were included. Mechanical ventilation was considered as early if it was introduced in the prehospital period or on arrival at the hospital. Occult PTXs were defined as PTXs not visible on chest x-ray. All PTXs were measured on CT scan (largest thickness and vertical dimension). Large occult PTXs were defined by a largest thickness of 30 mm or more.

RESULTS

Of the 526 patients studied, 395 (75%) were male, mean age was 37.9 years, mean Injury Severity Score was 22.2, and 247 (47%) received early mechanical ventilation. Of 429 diagnosed PTXs, 296 (69%) were occult. The proportion of occult PTXs classified as large was 11% (95% confidence interval, 8%-15%). The overall prevalence of large occult PTXs was 6% (95% confidence interval, 4%-8%). Both CT measurements and proportion of large occult PTXs were found statistically comparable in patients with or without mechanical ventilation.

CONCLUSIONS

Six percent of studied patients with severe trauma had a large and occult PTX as soon as admission despite a normal chest x-ray result. The observed sizes and rates of occult PTX were comparable regardless of the initiation of early mechanical ventilation.

Outcome of concurrent occult hemothorax and pneumothorax in trauma patients who required assisted ventilation

Background. The management and outcomes of occult hemopneumothorax in blunt trauma patients who required mechanical ventilation are not well studied. We aimed to study patients with occult hemopneumothorax on mechanical ventilation who could be carefully managed without tube thoracostomy. Methods. Chest trauma patients with occult hemopneumothorax who were on mechanical ventilation were prospectively evaluated. The presence of hemopneumothorax was confirmed by CT scanning. Hospital length of stay, complications, and outcome were recorded. Results. A total of 56 chest trauma patients with occult hemopneumothorax who were on ventilatory support were included with a mean age of 36 ± 13 years. Hemopneumothorax was managed conservatively in 72% cases and 28% underwent tube thoracostomy as indicated. 29% of patients developed pneumonia, 16% had Acute Respiratory Distress Syndrome (ARDS), and 7% died. Thickness of hemothorax, duration of mechanical ventilation, and development of ARDS were significantly associated with tube thoracostomy in comparison to no-chest tube group. Conclusions. The majority of occult hemopneumothorax can be carefully managed without tube thoracostomy in patients who required positive pressure ventilation. Tube thoracotomy could be restricted to those who had evidence of increase in the size of the hemothorax or pneumothorax on follow-up chest radiographs or developed respiratory compromise.

Thoracic ultrasound confirmation of correct lung exclusion before one-lung ventilation during thoracic surgery

INTRODUCTION

Fiberoptic bronchoscopy is the standard method for verifying the correct position of a double-lumen endotracheal tube (DLET) prior to one-lung ventilation. However, it must be performed by a specially trained anesthesiologist and is often resource consuming. The aim of this study was to compare this approach with thoracic ultrasound done by a nurse anesthetist in terms of sensitivity, specificity, and cost-effectiveness.

METHODS

We conducted a prospective cross-over case-control study involving 51 adult patients consecutively undergoing thoracic surgery with one-lung ventilation. After orotracheal intubation with a DLET, correct exclusion of the lung being operated on exclusion was assessed first by a certified anesthesiologist using standard fiberoptic bronchoscopy and then by a trained nurse anesthetist using thoracic ultrasound. The nurse was blinded as to the findings of the anesthesiologist's examination.

RESULTS

The two approaches proved to be equally sensitive and specific, but the ultrasound examination was more rapid. This factor, together with the fact that ultrasound was performed by a nurse instead of a physician, and the costs of materials and sterilization, had a significant economic impact amounting to a net saving of €37.20 ± 5.40 per case.

CONCLUSIONS

Although fiberoptic bronchoscopy is still the gold standard for checking the position of a DLET, thoracic ultrasound is a specific, sensitive, cost-effective alternative, which can be used to rapidly verify the proper function of the tube based on the demonstration of correct lung exclusion.

Occult pneumothoraces in critical care: a prospective multicenter randomized controlled trial of pleural drainage for mechanically ventilated trauma patients with occult pneumothoraces

BACKGROUND

Patients with an occult pneumothoraces (OPTXs) may be at risk of tension pneumothoraces (TPTXs) without drainage or pleural drainage complications if treated.

METHODS

Adults with traumatic OPTXs and requiring positive-pressure ventilation (PPV) were randomized to pleural drainage or observation (one side only enrolled if bilateral). All subsequent care and method of pleural drainage was per attending physician discretion. The primary outcome was a composite of respiratory distress (RD) (need for urgent pleural drainage, acute/sustained increases in O2 requirements, ventilator dysynchrony, and/or charted respiratory events).

RESULTS

Ninety severely injured patients (mean [SD], Injury Severity Score [ISS], 33 [11]) were studied at four centers: Calgary (55), Toronto (27), Quebec (6), and Sherbrooke (3). Forty were randomized to tube thoracostomy, and 50 were randomized to observation. The risk of RD was similar between the observation and tube thoracostomy groups (relative risk, 0.71; 95% confidence interval, 0.40-1.27). There was no difference in mortality or intensive care unit (ICU), ventilator, or hospital days between groups. In those observed, 20% required subsequent pleural drainage (40% PTX progression, 60% pleural fluid, and 20% other). One observed patient (2%) undergoing PPV at enrollment had a TPTX, which was treated with urgent tube thoracostomy without sequelae. Drainage complications occurred in 15% of those randomized to drainage, while suboptimal tube thoracostomy position occurred in an additional 15%. There were three times (24% vs. 8%) more failures and more RDs (p = 0.01) among those observed with OPTXs requiring sustained PPV versus just for an operation, which increases threefold after a week in the ICU (p = 0.07).

CONCLUSION

Our results suggest that OPTXs may be safely observed in hemodynamically stable patients undergoing PPV just for an operation, although one third of those requiring a week or more of ICU care received drainage, and TPTXs still occur. Complications of pleural drainage remain unacceptably high, and future work should attempt to delineate specific factors among those observed that warrant prophylactic drainage.

LEVEL OF EVIDENCE

Therapeutic study, level III.

Using thoracic ultrasonography to accurately assess pneumothorax progression during positive pressure ventilation: a comparison with CT scanning

BACKGROUND

Although thoracic ultrasonography accurately determines the size and extent of occult pneumothoraces (PTXs) in spontaneously breathing patients, there is uncertainty about patients receiving positive pressure ventilation. We compared the lung point (ie, the area where the collapsed lung still adheres to the inside of the chest wall) using the two modalities ultrasonography and CT scanning to determine whether ultrasonography can be used reliably to assess PTX progression in a positive-pressure-ventilated porcine model.

METHODS

Air was introduced in incremental steps into fi ve hemithoraces in three intubated porcine models. The lung point was identified on ultrasound imaging and referenced against the lateral limit of the intrapleural air space identified on the CT scans. The distance from the sternum to the lung point (S-LP) was measured on the CT scans and correlated to the insufflated air volume.

RESULTS

The mean total difference between the 131 ultrasound and CT scan lung points was 6.8 mm (SD, 7.1 mm; range, 0.0-29.3 mm). A mixed-model regression analysis showed a linear relationship between the S-LP distances and the PTX volume ( P , .001).

CONCLUSIONS

In an experimental porcine model, we found a linear relation between the PTX size and the lateral position of the lung point. The accuracy of thoracic ultrasonography for identifying the lung point (and, thus, the PTX extent) was comparable to that of CT imaging. These clinically relevant results suggest that ultrasonography may be safe and accurate in monitoring PTX progression during positive pressure ventilation.

The utility of special radiological signs on routinely obtained supine anteroposterior chest radiographs for the early recognition of neonatal pneumothorax

BACKGROUND

Bedside chest radiographs used for the confirmation of diagnosis of pneumothorax in the neonatal intensive care unit (NICU) are routinely obtained in the supine position. However, pneumothoraces may not appear in the classically described forms on these radiographs, resulting in a delayed diagnosis.

OBJECTIVE

To assess the utility of special radiological signs in the neonatal population for the early recognition of pneumothorax.

METHODS

A case-control study was conducted at a level III referral center from January 2006 to December 2012. For each neonate with pneumothorax, one infant was selected for the control group. A senior radiologist and neonatologist experienced in reading chest radiographs evaluated each radiograph for the presence of special radiological signs.

RESULTS

Of the 1,375 infants admitted to the NICU during the study period, 39 had a pneumothorax. A total of 223 radiographs were scored and 46% of the neonates were found to have occult pneumothoraces before they were clinically diagnosed. Twenty-six percent had a single sign detected on a radiograph, whereas 20% had multiple signs. The time interval between the appearance of these signs and clinical diagnosis ranged between 0.5 and 27 h.

CONCLUSIONS

The present study shows that the recognition of these signs would assist the physician in identifying occult pneumothorax earlier in its course. Physicians dealing with critically ill infants should ensure that they can recognize these radiological signs.

Sonographic diagnosis of pneumothorax

Lung sonography has rapidly emerged as a reliable technique in the evaluation of various thoracic diseases. One important, well-established application is the diagnosis of a pneumothorax. Prompt and accurate diagnosis of a pneumothorax in the management of a critical patient can prevent the progression into a life-threatening situation. Sonographic signs, including 'lung sliding', 'B-lines' or 'comet tail artifacts', 'A-lines', and 'the lung point sign' can help in the diagnosis of a pneumothorax. Ultrasound has a higher sensitivity than the traditional upright anteroposterior chest radiography (CXR) for the detection of a pneumothorax. Small occult pneumothoraces may be missed on CXR during a busy trauma scenario, and CXR may not always be feasible in critically ill patients. Computed tomography, the gold standard for the detection of pneumothorax, requires patients to be transported out of the clinical area, compromising their hemodynamic stability and delaying the diagnosis. As ultrasound machines have become more portable and easier to use, lung sonography now allows a rapid evaluation of an unstable patient, at the bedside. These advantages combined with the low cost and ease of use, have allowed thoracic sonography to become a useful modality in many clinical settings.

Can cervical spine computed tomography assist in detecting occult pneumothoraces?

INTRODUCTION

Screening CT often detects posttraumatic pneumothoraces that were not diagnosed on a preceding supine anteroposterior chest radiograph (occult pneumothoraces (OPTXs)). Because abdominal CT imaging misses OPTXs in the upper thorax, the objective of this study was to evaluate the utility of cervical spine (C-spine) CT screening for diagnosing OPTXs.

METHODS

A dual-institution (Foothills Medical Centre and Grady Memorial Hospital) retrospective review of consecutive OPTXs was performed. The accuracy of various CT screening protocols in detecting OPTXs was compared.

RESULTS

OPTXs were detected in 75 patients. Patient demographics and injury characteristics were similar between centres (65% male; 97% blunt mechanism; 29% hemodynamically unstable; mean ISS=27; mean length of stay=22 days; mortality=9%)(p>0.05). Patients received either abdominal (41%) or thoraco-abdominal (59%) CT imaging. Most patients (89%) also underwent C-spine CT imaging. OPTXs were evident on thoracic CT in 100% (44/44), abdominal CT in 83% (62/75), and C-spine CT in 82% (55/67) of cases. All patients with OPTXs identified solely on thoracic CT (i.e. not abdominal) who also underwent imaging of their C-spine could have had their OTPXs diagnosed by using the pulmonary windows setting of their C-spine CT series. Combining C-spine and abdominal CT screening diagnosed all OPTXs (67/67) detected on thoracic CT, for patients who also underwent these investigations.

CONCLUSIONS

OPTXs were evident on thoracic (and not abdominal) CT in 17% of severely injured patients. For patients who also underwent C-spine imaging, all OPTXs isolated to thoracic CT could be diagnosed by using the pulmonary windows setting of their C-spine CT imaging protocol. All OPTXs, regardless of intra-thoracic location, could also be detected by combining C-spine and abdominal CT screening.

My Patient is Short of Breath: Have They Got a Pneumothorax?

Clinical diagnosis of pneumothorax in the emergency department (ED) resuscitation room can be difficult and in certain circumstances chest radiography is either impractical or the delay is unacceptable. The diagnosis must also be considered in other clinical areas such as critical care, theatres, respiratory units and acute medical units. Erect chest radiography is the standard first-line diagnostic test for pneumothorax in the ED, but the sensitivity is low (59–81%). For many patients in ED, critical care and theatre, an erect chest radiograph is not possible as the patient must remain supine. The sensitivity for a supine chest radiograph has been reported as being 45–75%. Ultrasound has been shown to be more sensitive than chest radiography in the diagnosis of pneumothorax in certain settings. This paper outlines the evidence for ultrasound in the diagnosis of pneumothorax in the point of care setting; it describes the technique and discusses the clinical application of this imaging modality.

Comparison of different thoracic trauma scoring systems in regards to prediction of post-traumatic complications and outcome in blunt chest trauma

BACKGROUND

As accurate assessment of thoracic injury severity in the early phase after trauma is difficult, we compared different thoracic trauma scores regarding their predictive ability for the development of post-traumatic complications and mortality.

MATERIALS AND METHODS

Two hundred seventy-eight multiple trauma patients (ISS ≥ 16) age > 16 y with severe blunt chest trauma (AIS(chest) ≥ 3) admitted between 2000 and 2009 to Level I Trauma center were included. Exclusion criteria were severe traumatic brain injury (AIS(head) ≥ 3) and penetrating thoracic trauma. The association between AIS(chest), Pulmonary Contusion score (PCS), Wagner-score and Thoracic Trauma Severity score (TTS), and duration of ventilation, length of ICU stay, development of post-traumatic complications, and mortality was investigated. Statistical analysis was performed with χ(2)-test, ANOVA, logistic regression, and receiver operating characteristic (ROC) curve.

RESULTS

Patients' mean age was 42.7 ± 17.0 y, the mean injury severity score was 28.7 ± 9.3 points. Overall, 60 patients (21.6%) developed ARDS, 143 patients (51.4%) SIRS, 110 patients (39.6%) sepsis, and 36 patients (13.0%) MODS. Twenty-two patients (7.9%) died. Among the examined thoracic trauma scores only the TTS was an independent predictor of mortality. With the TTS showing the best prediction power, the TTS, PCS, and Wagner-score were independent predictors of ventilation time, length of ICU stay, and the development of post-traumatic ARDS and MODS.

CONCLUSIONS

Thoracic trauma scores combining anatomical and physiologic parameters like the TTS seem to be most suitable for severity assessment and prediction of outcome in multiple trauma patients with concomitant blunt chest trauma.

Blunt traumatic occult pneumothorax: is observation safe?--results of a prospective, AAST multicenter study

BACKGROUND

An occult pneumothorax (OPTX) is found incidentally in 2% to 10% of all blunt trauma patients. Indications for intervention remain controversial. We sought to determine which factors predicted failed observation in blunt trauma patients.

METHODS

A prospective, observational, multicenter study was undertaken to identify patients with OPTX. Successfully observed patients and patients who failed observation were compared. Multivariate logistic regression was used to identify predictors of failure of observation. OPTX size was calculated by measuring the largest air collection along a line perpendicular from the chest wall to the lung or mediastinum.

RESULTS

Sixteen trauma centers identified 588 OPTXs in 569 blunt trauma patients. One hundred twenty-one patients (21%) underwent immediate tube thoracostomy and 448 (79%) were observed. Twenty-seven patients (6%) failed observation and required tube thoracostomy for OPTX progression, respiratory distress, or subsequent hemothorax. Fourteen percent (10 of 73) failed observation during positive pressure ventilation. Hospital and intensive care unit lengths of stay, and ventilator days were longer in the failed observation group. OPTX progression and respiratory distress were significant predictors of failed observation. Most patient deaths were from traumatic brain injury. Fifteen percentage of patients in the failed observation group developed complications. No patient who failed observation developed a tension PTX, or experienced adverse events by delaying tube thoracostomy.

CONCLUSION

Most blunt trauma patients with OPTX can be carefully monitored without tube thoracostomy; however, OPTX progression and respiratory distress are independently associated with observation failure.

Occult pneumothoraces truly occult or simply missed: redux

BACKGROUND

As utilization of computed tomography (CT) scans in the evaluation of trauma patients increases, pneumothoraces (PTXs) seen on CT but not on chest X-ray (CXR), known as occult PTXs (OPTXs), are becoming more prevalent. The incidence of PTXs simply missed on CXR among OPTXs is unclear. A previous retrospective review of CXRs at our institution generally confirmed the occult versus missed designation, but lower fidelity images may have biased this determination. Thus, we repeated this evaluation using the high-quality images and improved the methodology.

METHODS

The 70 Digital Imaging and Communications in Medicine (DICOM)-quality CXR images were randomly selected from two prospectively collected trauma databases including 22 normal, 5 overt PTX, and 43 study OPTX images. All CXR images were corroborated with multidetector CT imaging. Two blinded fellowship-trained radiologists reviewed and evaluated all the images on an IMPAX viewer.

RESULTS

All images were deemed "adequate" except for one CXR by a single reviewer. For PTX diagnosis, agreement was 60% for overt PTXs, 86% for normal CXRs, and 81% for study OPTXs, yielding a kappa statistic of 0.51 (95% confidence interval, 0.22-0.81) indicating moderate agreement. Considering only the cases where the reviewers agreed, 80% of the study OPTXs were truly occult versus missed (95% confidence interval, 63-92%). In the 7 missed PTXs, subcutaneous emphysema (5), pleural line (3), and deep sulcus sign (2) were detected.

CONCLUSION

We estimate that 80% of PTXs considered occult in the trauma room were truly occult. The most common missed sign was subcutaneous emphysema. PTXs are poorly assessed by CXR, and accurate diagnosis should focus on other imaging modalities.

Bildgebende Verfahren: Röntgen, Ultraschall, CT, Nuklearmedizin

In der Intensivmedizin findet die radiologische Diagnostik überwiegend am Krankenbett statt (»bedside radiology«). Etwa 90 % der radiologischen Untersuchungen in der Intensiv- und Notfallmedizin stellen projektionsradiographische Röntgenaufnahmen des Thorax, des Abdomens und des Skelettsystems dar. In zunehmendem Maße werden neben den klassischen Aufnahmen auch die Schnittbildverfahren eingesetzt. Hier kommt der Ultraschalldiagnostik eine führende Rolle zu, gefolgt von der Computertomographie (CT).

Pneumothorax, pneumomediastinum, and pulmonary embolism

This article discusses pneumothorax, pneumomediastinum, and pulmonary embolism in pediatric practice. Although children appear to have better outcomes than adults, the risk factors are substantial. Topics covered include the pathophysiology incidence, presentation, diagnosis, and management of these diseases.

Occult pneumothorax, revisited

Pneumothorax is a recognized cause of preventable death following chest wall trauma where a simple intervention can be life saving. In cases of trauma patients where cervical spine immobilization is mandatory, supine AP chest radiograph is the most practical initial study. It is however not as sensitive as CT chest for early detection of a pneumothorax. "Occult" pneumothorax is an accepted definition of an existing but usually a clinically and radiologically silent disturbance that in most patients can be tolerated while other more urgent trauma needs are attended to. However, in certain patients, especially those on mechanical ventilation (with subsequent increase of intrapleural air with positive pressure ventilation), missing the diagnosis of pneumothorax can be deleterious with fatal consequences. This review will discuss the occult pneumothorax in the context of 3 radiological examples, which will further emphasize the entity. Because a negative AP chest radiograph can dangerously delay its recognition, we recommend that any trauma victim presenting to the emergency department with symptoms of respiratory distress should be screened with either thoracic ultrasonography or chest CT scan to avoid missing a pneumothorax.

Opening Pandora’s box: the potential benefit of the expanded FAST exam is partially confounded by the unknowns regarding the significance of the occult pneumothorax

Introduction

Point of care (POC) ultrasound brings another powerful dimension to the physical examination of the critically ill. A contemporary challenge for all care providers, however, is how to best incorporate ultrasound into contemporary algorithms of care. When POC ultrasound corroborates pre-examination clinical suspicion, incorporation of the findings into decision-making is easier. When POC ultrasound generates new or unexpected findings, decision-making may be more difficult, especially with conditions that were previously not appreciated with older diagnostic technologies. Pneumothoraces (PTXs), previously seen only on computed tomography and not on supine chest radiographs known as occult pneumothoraces (OPTXs), which are now increasingly appreciated on POC ultrasound, are such an example.

Methods

The relevant literature concerning POC ultrasound and PTXs was reviewed after an electronic search using PubMed supplemented by ongoing research by the Canadian Trauma Trials Collaborative of the Trauma Association of Canada.

Results

OPTXs are frequently encountered in the critically injured who often require mechanical ventilation with positive pressure breathing (PPB). Standard recommendations for post-traumatic PTXs and the setting of PPB mandate chest drainage, recognizing a significant rate of complications related to this procedure itself. Whether these standard recommendations generated in response to obvious overt PTXs apply to these more subtle OPTXs is currently unknown, and evidence-based recommendations regarding appropriate therapy are impossible due to the lack of clinical studies.

Conclusions

OPTXs are a condition that illustrates how incorporation of POC ultrasound findings brings further responsibilities to critically appraise the significance of these findings in terms of patient outcomes and overall care. Adequately powered and adequately followed-up clinical trials addressing the treatment are required.

Pleural ultrasound compared with chest radiographic detection of pneumothorax resolution after drainage

BACKGROUND

Pleural ultrasonography (PU) is more sensitive than chest radiograph (CXR) for diagnosing pneumothorax and could be useful for detecting resolution of pneumothorax after drainage. The aim of this prospective double-blind observational study was to assess PU accuracy during pneumothorax follow-up after drainage.

METHODS

All patients hospitalized with pneumothorax requiring drainage were eligible. After drainage, residual pneumothorax was assessed by CXR and PU (1) 24 h after bubbling in the aspiration device had stopped, (2) 6 h after clamping the pleural catheter, and (3) 6 h after removing the pleural catheter. Pneumothorax indicated by PU but not CXR was confirmed by CT scan or by aspiration of > 10 mL of air.

RESULTS

Forty-four unilateral pneumothoraces were studied (primary spontaneous: 70.5%), and 162 pairs of examinations (CXR and PU) were performed. Twenty residual pneumothoraces were detected by both CXR and PU. Furthermore, PU suspected 14 pneumothoraces that were not identified by CXR; 13 were confirmed. All of these pneumothoraces resulted in therapeutic intervention. Thus, 39% (13/33) of the confirmed residual pneumothoraces were missed by CXR. In patients with primary spontaneous pneumothorax, the positive predictive value of PU for residual pneumothorax diagnosis was 100%; for other pneumothoraces, this value ranged from 90% in the absence of a lung point to 100% when a lung point was observed. PU results were obtained faster than results from CXR (35 +/- 34 min vs 71 +/- 56 min, P < .0001).

CONCLUSIONS

The accuracy of PU is excellent for detecting residual pneumothorax during pneumothorax follow-up after drainage.

Sensitivity of bedside ultrasound and supine anteroposterior chest radiographs for the identification of pneumothorax after blunt trauma

OBJECTIVES

Supine anteroposterior (AP) chest radiographs in patients with blunt trauma have poor sensitivity for the identification of pneumothorax. Ultrasound (US) has been proposed as an alternative screening test for pneumothorax in this population. The authors conducted an evidence-based review of the medical literature to compare sensitivity of bedside US and AP chest radiographs in identifying pneumothorax after blunt trauma.

METHODS

MEDLINE and EMBASE databases were searched for trials from 1965 through June 2009 using a search strategy derived from the following PICO formulation of our clinical question: patients included adult (18 + years) emergency department (ED) patients in whom pneumothorax was suspected after blunt trauma. The intervention was thoracic ultrasonography for the detection of pneumothorax. The comparator was the supine AP chest radiograph during the initial evaluation of the patient. The outcome was the diagnostic performance of US in identifying the presence of pneumothorax in the study population. The criterion standard for the presence or absence of pneumothorax was computed tomography (CT) of the chest or a rush of air during thoracostomy tube placement (in unstable patients). Prospective, observational trials of emergency physician (EP)-performed thoracic US were included. Trials in which the exams were performed by radiologists or surgeons, or trials that investigated patients suffering penetrating trauma or with spontaneous or iatrogenic pneumothoraces, were excluded. The methodologic quality of the studies was assessed. Qualitative methods were used to summarize the study results. Data analysis consisted of test performance (sensitivity and specificity, with 95% confidence intervals [CIs]) of thoracic US and supine AP chest radiography.

RESULTS

Four prospective observational studies were identified, with a total of 606 subjects who met the inclusion and exclusion criteria. The sensitivity and specificity of US for the detection of pneumothorax ranged from 86% to 98% and 97% to 100%, respectively. The sensitivity of supine AP chest radiographs for the detection of pneumothorax ranged from 28% to 75%. The specificity of supine AP chest radiographs was 100% in all included studies.

CONCLUSIONS

This evidence-based review suggests that bedside thoracic US is a more sensitive screening test than supine AP chest radiography for the detection of pneumothorax in adult patients with blunt chest trauma.

Occult pneumothorax in the blunt trauma patient: tube thoracostomy or observation?

BACKGROUND

The term occult pneumothorax (OP) describes a pneumothorax that is not suspected on the basis of either clinical examination or initial chest radiography, but is subsequently detected on computed tomography (CT) scan. The optimal management of OP in the blunt trauma setting remains controversial. Some physicians favour placement of a thoracostomy tube for patients with OP, particularly those undergoing positive pressure ventilation (PPV), while others favour close observation without chest drainage. This study was conducted both to determine the incidence of OP and to describe its current treatment status in the blunt trauma population at a Canadian tertiary trauma centre. Of interest were the rates of tube thoracostomy vs. observation without chest drainage and their respective outcomes.

METHODS

A retrospective review was conducted of the Nova Scotia Trauma Registry. The data on all consecutive blunt trauma patients between October 1994 and March 2003 was reviewed. Outcome measures evaluated include length of stay, discharge status-dead vs. alive, intervention and time to intervention (tube thoracostomy and its relation to institution of PPV). Direct comparison was made between the OP with tube thoracostomy group and OP without tube thoracostomy group (observation or control group). They were compared in terms of their baseline characteristics and outcome measures.

RESULTS

In 1881 consecutive blunt trauma patients over a 102-month period there were 307 pneumothoraces of which 68 were occult. Thirty five patients with OP underwent tube thoracostomy, 33 did not. Twenty nine (82.8%) with tube thoracostomy received positive pressure ventilation (PPV), as did 16 (48.4%) in the observation group. Mean injury severity score (ISS) for tube thoracostomy and observation groups were similar (25.80 and 22.39, p=0.101) whereas length of stay (LOS) was different (17.4 and 10.0 days, p=0.026). Mortality was similar (11.4% and 9.1%). There were no tension pneumothoraces.

CONCLUSION

The natural history of OP in blunt trauma patients at our institution appears to be one of uneventful resolution irrespective of ISS, need for PPV, or placement of tube thoracostomy. This study suggests an interesting hypothesis that observation of the blunt trauma patient with OP, without tube thoracostomy, may be safe and contribute to a shorter hospital stay. These are observations that would benefit from further study in a large, prospective randomised controlled trial.

Clinical predictors of occult pneumothoraces in severely injured blunt polytrauma patients: A prospective observational study

INTRODUCTION

The supine antero-posterior (AP) chest radiograph (CXR) is an insensitive test for detecting post-traumatic pneumothoraces (PTXs). Computed tomography (CT) often identifies occult pneumothoraces (OPTXs) that were not diagnosed on CXR. The purpose of this study was to prospectively determine the incidence, and validate previously identified clinical predictors, of OPTXs after blunt trauma.

METHODS

All severe blunt injured patients (injury severity score (ISS)>or=12) presenting to a level 1 trauma centre over a 17-month period were prospectively evaluated. Thoracoabdominal CT scans and corresponding CXRs were reviewed at the time of admission. Patients with OPTXs were compared to those with overt PTXs regarding incidence and previously identified predictive risk factors (subcutaneous emphysema, rib fractures, female sex and pulmonary contusion).

RESULTS

CT imaging was performed concurrent to CXR in 405 blunt trauma patients (ISS>or=12) during the study period. PTXs were identified in 107 (26%) of the 405 patients. Eighty-one (76%) of these were occult when CXRs were interpreted by the trauma team. Concurrent chest trauma predictive of OPTXs was limited to subcutaneous emphysema (p=0.003). Rib fractures, pulmonary contusions and female sex were not predictive.

CONCLUSIONS

OPTXs were missed in up to 76% of all seriously injured patients when CXRs were interpreted by the trauma team. This is higher than previously reported in retrospective studies and is likely based on the difficult conditions in which the trauma team functions. Subcutaneous emphysema remains a strong clinical predictor for concurrent OPTXs.

Thoracic imaging in the ICU

Imaging in the ICU plays a crucial role in patient care. The portable chest radiograph (CXR) is the most commonly requested radiographic examination, and, despite its limitations, it often reveals abnormalities that may not be detected clinically. Recent advances in CT technology have made it possible to obtain diagnostic-quality images even in the most dyspneic patient. This article reviews the significant contribution thoracic imaging makes in diagnosing and managing critically ill patients.

Occult traumatic pneumothorax: diagnostic accuracy of lung ultrasonography in the emergency department

BACKGROUND

The role of chest ultrasonography (US) in the diagnosis of pneumothorax (PTX) has been established, but how it compares with lung CT scanning in the diagnosis of radiooccult PTX and in the determination of its topographic extension has not yet been completely evaluated.

OBJECTIVE

To determine the diagnostic accuracy of chest US in the emergency department (ED) in the diagnosis of occult PTX in trauma patients and to define its ability to determine PTX extension.

DESIGN

An 18-month prospective study.

PATIENTS

A total of 109 conscious, spontaneously breathing patients who had been admitted to the ED for chest trauma or polytrauma.

METHODS

All eligible patients underwent a standard anteroposterior supine chest radiograph (Rx) and a spiral CT lung scan within 1 h of ED admission. Lung US was carried out by an operator who was unaware of the other examination results, both for diagnosis and for the quantitative delimitation of the PTX.

RESULTS

Twenty-five traumatic PTXs were detected in the 218 hemithoraxes (109 patients; 2 patients had a bilateral PTX) evaluated by spiral CT scan; of these, only 13 of 25 PTXs (52%) were revealed by chest Rx (sensitivity, 52%; specificity, 100%), while 23 of 25 PTXs (92%) were identified by lung US with one false-positive result (sensitivity, 92%; specificity, 99.4%). In 20 of 25 cases, there was agreement on the extension of the PTX between CT lung scan and lung US with a mean difference of 1.9 cm (range, 0 to 4.5 cm) in the localization of retroparietal air extension; chest Rx was not able to give quantitative results.

CONCLUSIONS

Lung US scans carried out in the ED detect occult PTX and its extension with an accuracy that is almost as high as the reference standard (CT scanning).

Detection of occult pneumothoraces in the significantly injured adult with blunt trauma

BACKGROUND

Identification of pneumothoraces is essential during the initial assessment of major injury. Prompt intervention is crucial for effective resuscitation and for subsequent safe management. Historically, emergency departments have relied on chest X-ray for detection of pneumothoraces. More recently, the increasing availability of computed tomography (CT) has provided a more sensitive means of detection. Occult pneumothoraces are those that are missed on clinical examination and chest X-ray, but are detected on subsequent CT.

OBJECTIVE

To determine the incidence of occult pneumothoraces and their impact on subsequent management.

PATIENTS

All blunt trauma patients with CT scans from a single, large, adult emergency department in 1 year.

METHODS

Patient records were analysed to determine the proportion of pneumothoraces detected on CT that had not been previously detected on chest X-ray. Records were further examined to determine how many occult pneumothoraces required additional management after detection.

RESULTS

In all, 134 blunt trauma patients required a CT scan. Thirty-five pneumothoraces were detected in 27 patients; 15 were occult. Six of these 15 were managed with intercostal drain insertion, all proceeding to mechanical ventilation. Of the eight patients (one bilateral) managed observantly, all had uncomplicated recoveries. CT was significantly more sensitive in the detection of pneumothoraces (P=0.03). Retrospective review by a radiology specialist identified three chest X-rays that had findings (deep sulcus sign and prominent cardiac outline) that were suggestive of pneumothorax.

CONCLUSIONS

A sufficiently high proportion of pneumothoraces is missed on chest X-ray to advocate a low threshold for use of CT in the early assessment of blunt trauma patients, especially if mechanical ventilation is required for ongoing management.

The ultrasonographic deep sulcus sign in traumatic pneumothorax

A series of 186 patients with blunt chest trauma was studied with transthoracic ultrasonography to diagnose pneumothorax and to evaluate its size and location. The results were compared with bedside chest radiography and spiral CT scan. The prevalence of pneumothorax on CT scan was 56/186 (30.1%). Pneumothorax was proven on radiography in 30/56 cases without false positive results: "radiographic deep sulcus sign" was evident in 3/29 cases, 26/29 cases being occult. The ultrasound study demonstrated the presence of pneumothorax in 55/56 patients: one occult pneumothorax was missed and no false positive results were observed. The CT scan differed of +/-2.3 cm (range 1-5 cm) from the US study in evaluating size and location of pneumothorax. In conclusion, ultrasound study may detect occult pneumothorax undiagnosed by standard plain radiography. It reflects accurately the extent of pneumothorax if compared with CT scan, outlining the "ultrasonographic deep sulcus sign" on anterior chest wall.

Imaging of Pleural Disease

Imaging plays an important role in the diagnosis and subsequent management of patients with pleural disease. The presence of a pleural abnormality is usually suggested following a routine chest x-ray, with a number of imaging modalities available for further characterization. This article describes the radiographic and cross-sectional appearances of pleural diseases, which are commonly encountered in every day practice. The conditions covered include benign and malignant pleural thickening, pleural effusions, empyema and pneumothoraces. The relative merits of CT, MRI and PET in the assessment of these conditions and the role of image-guided intervention are discussed.

Are Occult Pneumothoraces Truly Occult or Simply Missed?

BACKGROUND

Nonradiologists typically diagnose pneumothoraces (PTX) based on a visible pleural stripe. PTXs not seen on supine AP chest radiographs (CXR), but appreciated on a computed tomographic (CT) scan, termed occult pneumothoraces (OPTX), are increasingly common. The purpose was to (1) determine whether perceived OPTXs were truly occult or simply missed and (2) address factors that contribute to the poor sensitivity of the supine CXR.

METHODS

A previous study of severely injured patients (ISS >or =12) identified 44 patients with OPTXs. JPEG images of these CXRs were randomly arranged with images of 11 injured patients without PTXs (CT proven). Three unique groups of radiologists reviewed the images for signs of PTXs, and determined if a thoracic CT was subsequently required.

RESULTS

Retrospective review identified only 12 to 24% of the OPTXs depending on radiology group. The kappa inter-observer agreement value was 0.55 to 0.56 (poor agreement). PTXs were most commonly identified via the deep sulcus sign (75-90%). CXRs were considered inadequate in 16 to 25% of OPTX images and in 0 to 18% of images without OPTXs. Thoracic CT scans were recommended in 18 to 33% of patients with inadequate CXRs, but 67 to 82% of patients with adequate CXRs.

CONCLUSIONS

Less than 24% of all OPTXs might have been inferred from subtle radiologic findings, such as the deep sulcus sign. The majority of OPTX cases (50-64%) did not warrant a CT scan based on other findings. Concern for an OPTX after severe trauma is a valid indication for thoracic CT.

Incidence, Risk Factors, and Outcomes for Occult Pneumothoraces in Victims of Major Trauma

BACKGROUND

The supine anteroposterior chest radiograph (CXR) is an insensitive test for posttraumatic pneumothoraces (PTXs). Computed tomographic (CT) scanning often detects PTXs that were not diagnosed on CXR (occult PTXs [OPTXs]). The purpose of this study was to define the incidence, predictors, and outcomes for OPTXs after trauma.

METHODS

Thoracoabdominal CT scans and corresponding CXRs of all trauma patients entered into a regional database were reviewed. Patients with OPTXs were compared with those with overt, residual, and no PTXs regarding incidence, demographics, associated injuries, early resuscitative predictors, treatment, and outcomes.

RESULTS

Paired CXRs and CT scans were available for 338 of 761 (44%) patients (98.5% blunt trauma). One hundred three PTXs were present in 89 patients, 57 (55%) of which were occult; 6 (11%) were seen only on thoracic CT scan. Age, sex, length of stay, and survival were similar between all groups. OPTXs and PTXs were similar in comparative size index and number of images. Subcutaneous emphysema, pulmonary contusion, rib fracture(s), and female sex were independent predictors of OPTXs. Seventeen (35%) patients with OPTXs were ventilated, of whom 13 (76%) underwent thoracostomy. No complications resulted from observation, although 23% of patients with thoracostomy had tube-related complications or required repositioning.

CONCLUSION

OPTXs are commonly missed both by CXR and even abdominal CT scanning in seriously injured patients. Basic markers available early in resuscitation are highly predictive for OPTXs and may guide management before CT scanning. Further study of OPTX detection and management is required.

Factors related to the failure of radiographic recognition of occult posttraumatic pneumothoraces

PURPOSE

Although posttraumatic pneumothoraces (PTXs) are common and potentially life threatening, the supine chest radiograph (CXR) is an insensitive test for their detection. Computed tomography (CT) often identifies occult pneumothoraces (OPTXs). Previous descriptions of OPTX topography have been poor. Our purpose was to define their distribution and aid in the targeting of thoracic ultrasound.

METHODS

Posttraumatic supine CXRs and CTs were reviewed for occult, overt, and residual PTXs. PTXs were compared according to their apical, basal, anterior, lateral, medial, and posterior components. A comparative size index was calculated.

RESULTS

Among 761 patients, 338 CT scans revealed 103 PTXs in 89 patients; 55% were OPTXs. OPTXs were apical (57%), basal (41%), anterior (84%), lateral (24%), and medial (27%), with 0% posterior.

CONCLUSIONS

CXR missed over half of all PTXs. OPTXs had a greater anterior versus lateral (nearly 4-fold) and both basal and apical versus lateral (2-fold) distribution. OPTXs are often located at easily accessible sonographic windows.

[Diagnosis and immediate therapeutic management of chest trauma. A systematic review of the literature]

OBJECTIVE

Injuries to the chest contribute significantly to the morbidity and mortality in multiple injured patients. This systematic review focuses on evidence based initial diagnostics and emergency room management of chest trauma.

METHODS

Clinical trials was systematically collected (Medline, Cochrane and hand searches) and classified into evidence levels (1 to 5 according to the Oxford system).

RESULTS

There are only a few studies that document the impact of injury mechanism and clinical examination of the patient. There is a positive correlation between crash severity or lateral impact with injury severity. Auscultation was found to be very sensitive in the detection of pneumothorax. Helical CT of the chest is most important in the initial work-up. Aortography is only indicated in selected cases. Whether tube thoracostomy is necessary in patients with occult pneumotharaces is still a matter of discussion. Indications for endotracheal intubation are poorly investigated and predominantly based on expert opinion.

CONCLUSION

Numerous comparative studies (LE 2) dealing with emergency diagnostics and therapy of chest trauma are available, however only a few randomized studies do exist. Based on the available data a rational therapy of chest trauma is possible.

Hand-held thoracic sonography for detecting post-traumatic pneumothoraces: the Extended Focused Assessment with Sonography for Trauma (EFAST)

BACKGROUND

Thoracic ultrasound (EFAST) has shown promise in inferring the presence of post-traumatic pneumothoraces (PTXs) and may have a particular value in identifying occult pneumothoraces (OPTXs) missed by the AP supine chest radiograph (CXR). However, the diagnostic utility of hand-held US has not been previously evaluated in this role.

METHODS

Thoracic US examinations were performed during the initial resuscitation of injured patients at a provincial trauma referral center. A high frequency linear transducer and a 2.4 kg US attached to a video-recorder were used. Real-time EFAST examinations for PTXs were blindly compared with the subsequent results of CXRs, a composite standard (CXR, chest and abdominal CT scans, clinical course, and invasive interventions), and a CT gold standard (CT only). Charts were reviewed for in-hospital outcomes and follow-up.

RESULTS

There were 225 eligible patients (207 blunt, 18 penetrating); 17 were excluded from the US examination because of battery failure or a lost probe. Sixty-five (65) PTXs were detected in 52 patients (22% of patients), 41 (63%) being occult to CXR in 33 patients (14.2% whole population, 24.6% of those with a CT). The US and CXR agreed in 186 (89.4%) of patients, EFAST was better in 16 (7.7%), and CXR better in 6 (2.9%). Compared with the composite standard, the sensitivity of EFAST was 58.9% with a likelihood ratio of a positive test (LR+) of 69.7 and a specificity of 99.1%. Comparing EFAST directly to CXR, by looking at each of 266 lung fields with the benefit of the CT gold standard, the EFAST showed higher sensitivity over CXR (48.8% versus 20.9%). Both exams had a very high specificity (99.6% and 98.7%), and very predictive LR+ (46.7 and 36.3).

CONCLUSION

EFAST has comparable specificity to CXR but is more sensitive for the detection of OPTXs after trauma. Positive EFAST findings should be addressed either clinically or with CT depending on hemodynamic stability. CT should be used if detection of all PTXs is desired.

Damage control: extremities

The principles of fracture management in polytrauma patients continue to be of crucial importance. Over the last five decades, various strategies of fracture treatment in the multiply injured patient have evolved. The various new methodologies remain controversial. In the beginning, early surgical fracture treatment of long bone fractures after multiple trauma was not routinely advocated. It was believed that the polytraumatised patient did not have the physiological reserve to withstand prolonged operations. The introduction of standardised, definitive surgical protocols, led to the concept of early total care (ETC) in the 1980s. This concept was subsequently applied universally, in all patient groups, regardless of injury severity and distribution. Later, it became apparent that certain patients did not appear to benefit from ETC. Indeed, extended operative procedures, during the early phase of multiple trauma recovery, were associated with adverse outcome. This applied for patients with significant thoracic, abdominal and head injuries and those with high injury severity scores (ISS). In response, the concept of damage control orthopaedics (DCO) was developed in the 1990s. DCO methodology is characterised by primary, rapid, temporary fracture stabilization. Secondary definitive management follows, once the acute phase of systemic recovery has passed. We explore the processes underlying the systemic biological impact of fracture fixation, the evolution of operative treatment strategies for major fractures in polytrauma and the current trends toward staged management of these patients.

Prevalence and importance of pneumothoraces visualized on abdominal computed tomographic scan in children with blunt trauma

BACKGROUND

Chest radiographs are routinely obtained for the identification of pneumothoraces in trauma patients. Computed tomographic (CT) scanning has a higher sensitivity for the detection of pneumothoraces, but the prevalence and importance of pneumothoraces detectable by CT scan but not by chest radiography in children sustaining blunt trauma is unclear.

METHODS

We conducted a prospective observational cohort study of children less than 16 years old with blunt trauma undergoing both abdominal CT scan and chest radiography in the emergency department of a Level I trauma center over a 28-month period. All abdominal CT scans were interpreted by a single faculty radiologist. The chest radiographs of all patients with pneumothoraces detected on CT scan as well as a random sample of chest radiographs from pediatric blunt trauma patients without pneumothoraces on abdominal CT scan (in a ratio of four normals per pneumothorax) were reviewed by a second faculty radiologist. Both radiologists were masked to all clinical data as well as to the objective of the study.

RESULTS

Five hundred thirty-eight children underwent both abdominal CT scan and chest radiography in the emergency department. Twenty patients (3.7%; 95% confidence interval [CI], 2.3-5.7%) were found to have pneumothoraces on CT scan. Of these 20 patients, 9 (45%; 95% CI, 23-68%) had pneumothoraces identified on initial chest radiography and 11 patients did not ("unsuspected pneumothoraces"). Twelve pneumothoraces were identified in these 11 patients; 6 were graded as minuscule and 6 as anterior according to a previously established scale. One patient with an unsuspected pneumothorax underwent tube thoracostomy. None of the 10 patients (0%; 95% CI, 0-26%) with unsuspected pneumothoraces who were managed without thoracostomy (including two patients who underwent positive pressure ventilation) had complications from their pneumothoraces.

CONCLUSION

Less than half of pediatric blunt trauma patients with pneumothoraces visualized on abdominal CT scan had these pneumothoraces identified on initial chest radiograph. Patients with pneumothoraces identified solely on abdominal CT scan, however, uncommonly require tube thoracostomy.