Validity of CT classification on management of occult pneumothorax: a prospective study

Mechanical Ventilation Does Not Predict Pneumothorax Observation Failure in the Severely Injured

BACKGROUND

Observative management of small traumatic pneumothoraces (PTX) has been shown to decrease chest tube utilization in non-mechanically ventilated patients without compromising outcomes. This approach could be used in mechanically ventilated (MV) patients, though many feel these patients are at increased risk of observation failure.

METHODS

A single center retrospective study of all adults undergoing observation of a computed tomography (CT) diagnosed PTX from 2015-2019. Patients with chest tube placement within 4-hours of arrival, concurrent hemothorax, or death within 24-hours were excluded. Observation failure was defined as chest tube placement.

RESULTS

Of 340 patients, 64 were on MV. The groups were of similar age, BMI, underlying pulmonary comorbidities, and PTX size (10.1 mm vs 8.8 mm, P = .20). The MV group was more severely injured (ISS [25+] [60.9% vs 11.2%, P < .001]). There was no difference in observation failure rates by MV status overall (6.3% vs 5.1%, P = .75) or by PTX size (<15 mm [5% vs 2.2%, P = .37], <20 mm [4.8% vs 3.1%, P = .45], <25 mm [4.8% vs 4.1%, P = .73], <30 mm [4.8% vs 4.1%, P = .73], <35 mm [4.8% vs 4.7%, P = 1.00]). MV was not an independent predictor of observation failure on multivariable analysis (OR .64, 95% CI .18-2.20), though PTX size was (OR 1.11, 95% CI 1.05-1.17). When comparing those who failed vs those who did not, the only difference was PTX size (9.34 mm vs 19.41 mm, P < .001).

CONCLUSION

MV is not an independent predictor of PTX observation failure. While PTX size appears to play a role, further studies are needed to outline safe parameters for observation in those undergoing MV.

Occult Pneumothorax in Blunt Thoracic Trauma: Clinical Characteristics and Results of Delayed Tube Thoracostomy in a Level 1 Trauma Center

Occult pneumothorax in blunt trauma patients is often diagnosed only after computed tomography because supine chest X-ray (CXR) is preferred as an initial evaluation. However, improperly managed preexisting occult pneumothorax could threaten the vitality of patients. Therefore, this study aimed to evaluate the incidence, characteristics, risk factors, and outcomes of occult pneumothorax in a single trauma center. From 2020 to 2022, patients who were admitted to the level 1 trauma center were retrospectively investigated. Inclusion criteria focused on blunt chest trauma. Variables including demographic factors, image findings, injury-related factors, tube thoracostomy timing, and treatment results were evaluated. Of the 1621 patients, 187 who met the criteria were enrolled in the study: 32 with overt pneumothorax and 81 with occult pneumothorax. Among all of the pneumothorax cases, the proportion of occult pneumothorax was 71.7% (81/113), and its incidence in all admitted trauma victims was 5.0% (81/1621). Subcutaneous emphysema and rib fractures on supine CXR were risk factors for occult pneumothorax. Six patients underwent delayed tube thoracostomy; however, none had serious complications. Given that occult pneumothorax is common in patients with blunt chest trauma, treatment plans should be established that consider the possibility of pneumothorax. However, the prognosis is generally good, and follow-up is an alternative.

Blunt trauma related chest wall and pulmonary injuries: An overview

Physical traumas are tragic and multifaceted injuries that suddenly threaten life. Although it is the third most common cause of death in all age groups, one out of four trauma patients die due to thoracic injury or its complications. Blunt injuries constitute the majority of chest trauma. This indicates the importance of chest trauma among all traumas. Blunt chest trauma is usually caused by motor vehicle accident, falling from height, blunt instrument injury and physical assault. As a result of chest trauma, many injuries may occur, such as pulmonary injuries, and these require urgent intervention. Chest wall and pulmonary injuries range from rib fractures to flail chest, pneumothorax to hemothorax and pulmonary contusion to tracheobronchial injuries. Following these injuries, patients may present with a simple dyspnea or even respiratory arrest. For such patient, it is important to understand the treatment logic and to take a multidisciplinary approach to treat the pulmonary and chest wall injuries. This is because only 10% of thoracic trauma patients require surgical operation and the remaining 90% can be treated with simple methods such as appropriate airway, oxygen support, maneuvers, volume support and tube thoracostomy. Adequate pain control in chest trauma is sometimes the most basic and best treatment. With definite diagnosis, the morbidity and mortality can be significantly reduced by simple treatment methods.

Integrating extended focused assessment with sonography for trauma (eFAST) in the initial assessment of severe trauma: Impact on the management of 756 patients

BACKGROUND

Before total body computed tomography scan, an initial rapid imaging assessment should be conducted in the trauma bay. It generally includes a chest x-ray, pelvic x-ray, and an extended focused ultrasonography assessment for trauma. This initial imaging assessment has been poorly described since the increase in the use of ultrasound. Therefore, our study aimed to evaluate the diagnostic accuracy and therapeutic impact of this initial imaging work-up in severe trauma patients. A secondary aim was to assess the therapeutic impact of a chest x-ray according to the lung ultrasonography findings.

METHODS

Patients with severe trauma who were admitted directly to our level 1 trauma center were consecutively included in this retrospective single center study. The diagnostic accuracy, therapeutic impact, and appropriate decision rate were calculated according to the initial assessment results of the whole body computed tomography scan and surgery reports.

RESULTS

Among the 1315 trauma patients admitted, 756 were included in this research. Lung ultrasound showed a higher diagnostic accuracy for haemothorax and pneumothorax cases than the chest x-ray. Sensitivity and specificity of the abdominal ultrasound to detect intraperitoneal effusion were 70% and 96%, respectively. The initial assessment had a therapeutic impact in 76 (10%) of the patients, including 16 (2%) immediate laparotomies and 58 (7%) chest tube insertions. The pelvic x-ray had no therapeutic impact, and when the lung ultrasound was normal, the chest x-ray had a therapeutic impact of only 0.13%. Combining the chest x-ray and lung ultrasound allowed adequate management of all the pneumothorax and haemothorax cases. Only one of the 756 patients had initial management that was judged as inappropriate. This patient had a missed pelvic disjunction with active retroperitoneal bleeding, and underwent an inappropriate immediate laparotomy.

CONCLUSIONS

In our cohort, the initial imaging assessment allowed appropriate decisions in 755 of 756 patients, with a global therapeutic impact of 10%. The pelvic x-ray had a minimal therapeutic impact, and in the patients with normal lung ultrasounds, the chest x-ray marginally affected the management of our patients. The potential consequences of abandoning systematic chest and pelvic x-rays should be investigated in future randomized prospective studies.

Comparison of Four Views to Single-view Ultrasound Protocols to Identify Clinically Significant Pneumothorax

OBJECTIVE

Ultrasound (US) has been shown to be effective at identifying a pneumothorax (PTX); however, the additional value of adding multiple views has not been studied. Single- and four-view protocols have both been described in the literature. The objective of this study was to compare the diagnostic accuracy of single-view versus four-view lung US to detect clinically significant PTX in trauma patients.

METHODS

This was a randomized, prospective trial on trauma patients. Adult patients with acute traumatic injury undergoing computed tomography (CT) scan of the chest were eligible for enrollment. Patients were randomized to a single view or four views of each hemithorax prior to any imaging. USs were performed and interpreted by credentialed physicians using a 7.5-Mhz linear array transducer on a portable US machine with digital clips recorded for later review. Attending radiologist interpretation of the chest CT was reviewed for presence or absence of PTX with descriptions of small foci of air or minimal PTX categorized as clinically insignificant.

RESULTS

A total of 260 patients were enrolled over a 2-year period. A total of 139 patients received a single view of each chest wall and 121 patients received four views. There were a total of 49 patients that had a PTX (19%), and 29 of these were clinically significant (11%). In diagnosis of any PTX, both single-view and four-view techniques showed poor sensitivity (54.2 and 68%) but high specificity (99 and 98%). For clinically significant PTX, single-view US demonstrated a sensitivity of 93% (95% confidence interval [CI] = 64.1% to 99.6%) and a specificity of 99.2% (95% CI = 95.5% to 99.9%), with sensitivity of 93.3% (95% CI = 66% to 99.7%) and specificity of 98% (95% CI = 92.1% to 99.7%) for four views.

CONCLUSIONS

Single-view and four-view chest wall USs demonstrate comparable sensitivity and specificity for PTX. The additional time to obtain four views should be weighed against the absence of additional diagnostic yield over a single view when using US to identify a clinically significant PTX.

Critical pitfalls in the immediate assessment of the trauma patient

In the immediate assessment of trauma patients, critical pitfalls exist that may interfere with optimal clinical care. Failure to recognize the need for early anaesthesia and endotracheal intubation may put the patient at unnecessary risk and delay the assessment and treatment process. Pressure to clear the cervical spine may lead to inadequate imaging and premature removal of neck immobilization devices. The limitations of the initial chest X-ray in diagnosing pneumothoraces may not be appreciated and needle thoracentesis may be ineffective. ‘Springing’ the pelvis to assess for instability may cause life-threatening haemorrhage and should not be done prior to the initial pelvic X-ray. Log rolling may dislodge crucial clot formation and promote bleeding, and should only be used for diagnostic purposes. Applying clinical common sense to the assessment of trauma patients may avoid the pitfalls whilst allowing the clinician to operate within internationally agreed assessment and treatment frameworks.

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.

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.

[Results of conservative treatment in patients with occult pneumothorax]

INTRODUCTION

An occult pneumothorax is found in 2-15% trauma patients. Observation (without tube thoracostomy) in these patients presents still some controversies in the clinical practice. The objective of the study is to evaluate the efficacy and the adverse effects when observation is performed.

METHODS

A retrospective observational study was undertaken in our center (university hospital level II). Data was obtained from a database with prospective registration. A total of 1087 trauma patients admitted in the intensive care unit from 2006 to 2013 were included.

RESULTS

In this period, 126 patients with occult pneumothorax were identified, 73 patients (58%) underwent immediate tube thoracostomy and 53 patients (42%) were observed. Nine patients (12%) failed observation and required tube thoracostomy for pneumothorax progression or hemothorax. No patient developed a tension pneumothorax or experienced another adverse event related to the absence of tube thoracostomy. Of the observed patients 16 were under positive pressure ventilation, in this group 3 patients (19%) failed observation. There were no differences in mortality, hospital length of stay or intensive care length of stay between the observed and non-observed group.

CONCLUSION

Observation is a safe treatment in occult pneumothorax, even in pressure positive ventilated patients.

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.

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.

Retrospective review of the use and costs of routine chest x rays in a trauma setting

INTRODUCTION

Chest x-rays (CXR) are routinely obtained on blunt trauma patients. Many patients also receive additional imaging with thoracic computed tomography scans for other indications. We hypothesized that in hemodynamically normal, awake and alert blunt trauma patients, CXR can be deferred in those who will also receive a TCT with significant cost savings.

METHODS

We retrospectively reviewed the charts of trauma patients from 1/1/2010 to 12/31/2010 who received both a CXR and TCT in the trauma room. Billing and cost data were collected from various hospital sources.

RESULTS

239 patients who met inclusion and exclusion criteria and received CXR and TCT between 1/1/2010 and 12/31/2010. The sensitivity of CXR was 19% (95% CI: 10.8% to 31%) and the specificity was 91.7% (95% CI: 86.7% to 95%). The false positive rate for CXR was 35.8% (95% CI: 21.7% to 52.8%) and the false negative rate was 24.5% (95% CI: 18.8% to 31.2%). The precision of CXR was 42.3% (95% CI: 25.5% to 61.1%) and the overall accuracy was 74.1% (95% CI: 68.1% to 79.2%). If routine chest xray were eliminated in these patients, the estimated cost savings ranged from $14,641 to $142,185, using three different methods of cost analysis.

CONCLUSIONS

In patients who are hemodynamically normal and who will be receiving a TCT, deferring a CXR would result in an estimated cost savings up to $142,185. Additionally, TCT is more sensitive and specific than CXR in identifying injuries in patients who have sustained blunt trauma to the thorax.

Occult pneumothoraces in acute trauma patients

INTRODUCTION

Many traumatic pneumothoraces (PTX) are not seen on initial chest radiograph (CR) (occult PTX) but are detected only on computed tomography (CT). Although CR remains the first tool for detecting PTX, most trauma patients with significant thoracoabdominal injuries will receive both CT and CR. The primary objective of this study was to retrospectively determine the effectiveness of CR for detecting PTX in trauma patients. Our hypotheses were that CR is a sensitive indicator of PTX on CT, that chest pain and shortness of breath are good predictors of PTX on CR, and that we could determine other predictors of PTX on CR.

METHODS

All trauma patients presenting to our Level I trauma center with a CT-diagnosed PTX over a 2-year period who had both a CR and a chest CT were included. The CT reading was considered the gold standard for PTX diagnosis. Electronic medical records were searched using key words for diagnoses, symptoms, demographics, and radiologic results. We recorded the official radiologist readings for both CR and CT (positive or negative) and the size of the PTX on CT (large, moderate, small, or tiny). The outcome variable was dichotomized based on presence or absence of PTX detected on CR. Descriptive statistics and χ(2) tests were used for univariate analysis. A regression analysis was performed to determine characteristics predictive of a PTX on CR, and 1 variable was added to the model for every 10 positive CRs. With equal-size groups, this study has the power of 80% to detect a 10% absolute difference in single predictors of PTX on CR with 45 subjects in each group.

RESULTS

There were 134 CT-documented PTXs included in the study. Mean age was 42, and 74% were men. For 66 (49%) patients, PTX was detected on CR (sensitivity = 50%). The CR detected 30% of small PTX, 35% of moderate PTX, and 33% of large PTX. Comparing patients with and without PTX on CR, there were no significant differences in shortness of breath or chest pain. There no relationships between PTX detected on CR and age, gender, penetrating versus blunt injury, bilaterality of the PTX, or presence of lung contusion or hemothorax on CT. After adjusting for all significant variables, predictor of a PTX detected on CR was air in the tissue on CR (adjusted odds ratio [OR] = 3.8) and PTX size (compared to a tiny PTX, adjusted OR = 2.0 for a small PTX, 7.5 for a moderate PTX, and 51 for a large PTX). Chest tubes were used in 89% of patients with PTX on CR and 44% of patients with PTX only on CT (difference 45%; 95% confidence interval 30, 58).

CONCLUSION

Factors associated with PTX on CR included air in the soft tissue on CR and size of the PTX. Even when PTX is not apparent on CR, 44% of these PTXs received placement of a chest tube.

Occult pneumothoraces in Chinese patients with significant blunt chest trauma: radiological classification and proposed clinical significance

BACKGROUND

An occult pneumothorax (OP) is a pneumothorax not seen on a supine chest X-ray (CXR) but detected on abdominal or thoracic computed tomography (CT) scanning. With the increasing use of CT in the management of significantly injured trauma patients, more OPs are being detected. The aim of this study was to classify OPs diagnosed on thoracic CT (TCT) and correlate them with their clinical significance.

METHODS

Retrospective analysis of prospectively collected trauma registry data. Total 36 (N=36) consecutive significantly injured trauma patients admitted through the emergency department (ED) who sustained blunt chest trauma and underwent TCT between 1 January 2007 and 31 December 2008 were included. OP was defined as the identification (by a consultant radiologist) of a pneumothorax on TCT that had not been detected on supine CXR. OPs were classified by laterality (unilateral/bilateral) and location (apical, basal, non apical/basal). The size of pneumothoraces, severity of injury [including number of associated thoracic injuries and injury severity score (ISS)], length of hospital stay and mortality were compared between groups. The need for tube thoracostomy and clinical outcome were also analysed.

RESULTS

Patients with bilateral OPs (N=8) had significantly more associated thoracic injuries (median: 2 vs. 1, p=0.01), higher ISS (median: 35 vs. 23, p=0.02) and longer hospital stay (median: 20 days vs. 11 days, p=0.01) than those with a unilateral OP (N=28). Basal OPs (N=7) were significantly larger than apical (N=10) and non-apical/basal Ops (N=11). Basal OPs were associated with significantly more associated thoracic injuries (median: 2 vs. 1, p=0.01), higher ISS (median: 35 vs. 25, p=0.04) and longer hospital stays (median: 23 days vs. 17 days, p=0.02) than apical Ops, which had higher ISS (median: 35 vs. 25, p=0.04) and longer hospital stays (median: 23 days vs. 15 days, p=0.02) than non-apical/basal OPs. Non-apical/basal OPs were associated with more related injuries (median: 2 vs. 1, p=0.02) than apical OPs. All apical and non-apical/basal OPs were successfully managed expectantly without associated mortality.

CONCLUSION

This TCT classification of OP is proposed to help clinicians to decide on subsequent management of the OP. Basal OPs are significantly larger in size, and both basal and bilateral OPs are associated with higher severity of injury and longer hospital stay. These groups of patient may benefit from prophylactic tube thoracostomy instead of conservative treatment. On the other hand, apical and non-apical/basal groups is smaller in size, less severely injured and thus can be successfully managed expectantly.

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.

Anteroposterior chest radiograph vs. chest CT scan in early detection of pneumothorax in trauma patients

Pneumothorax is a common complication following blunt chest wall trauma. In these patients, because of the restrictions regarding immobilization of the cervical spine, Anteroposterior (AP) chest radiograph is usually the most feasible initial study which is not as sensitive as the erect chest X-ray or CT chest for detection of a pneumothorax. We will present 3 case reports which serve for better understanding of the entity of occult pneumothorax. The first case is an example of a true occult pneumothorax where an initial AP chest X-ray revealed no evidence of pneumothorax and a CT chest immediately performed revealed evidence of pneumothorax. The second case represents an example of a missed rather than a truly occult pneumothorax where the initial chest radiograph revealed clues suggesting the presence of pneumothorax which were missed by the reading radiologist. The third case emphasizes the fact that "occult pneumothorax is predictable". The presence of subcutaneous emphesema and pulmonary contusion should call for further imaging with CT chest to rule out pneumothorax. Thoracic CT scan is therefore the "gold standard" for early detection of a pneumothorax in trauma patients. This report aims to sensitize readers to the entity of occult pneumothorax and create awareness among intensivists and ER physicians regarding the proper diagnosis and management.

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.

Ability of a chest X-ray and an abdominal computed tomography scan to identify traumatic thoracic injury

OBJECTIVE

Our objective was to show that a chest X-ray (CXR) and an abdominal computed tomography (CT) scan are sufficient to identify most clinically significant thoracic injuries in trauma patients, rendering the thoracic CT scan useful in only a subset of patients.

METHODS

A retrospective study identified thoracic injuries in 374 trauma patients evaluated with a CXR, a thoracic CT scan, and an abdominal CT scan. Injuries seen on the initial CXR versus those seen on a CT scan only (occult) were identified and assessed for clinical relevance.

RESULTS

An abdominal CT scan identified 65% (15/23) of occult pneumothoraces, 100% (25/25) of occult hemothoraces, 64% (18/28) of occult pulmonary contusions, and 58% (18/31) of occult rib fractures. No occult pneumothoraces seen on the thoracic CT scan alone required tube thoracostomy.

CONCLUSIONS

Our pilot study suggests that a CXR and an abdominal CT scan will identify most occult intrathoracic injuries. Reserving a thoracic CT scan for patients with an abnormal CXR or high-risk mechanism could safely reduce cost and radiation exposure while still diagnosing significant thoracic injuries.

Management of traumatic occult pneumothorax

STUDY OBJECTIVE

Occult pneumothorax (OPTX) is defined as a pneumothorax seen on computed tomography but not apparent on supine plain radiography. Though increasingly common, the acute management of OPTX after trauma remains controversial. This evidence-based review evaluates the existing evidence regarding the safety and efficacy of observation as compared to tube thoracostomy (TT) for management of OPTX in emergency department trauma patients.

METHODS

The authors searched MEDLINE, EMBASE, the Cochrane Library, and other databases.

INCLUSION CRITERIA

studies of adult or pediatric trauma victims at first presentation after blunt or penetrating injury (population), randomized to observation (intervention) or TT (comparison). Studies that enrolled patients on positive pressure ventilation were included but those that enrolled hemodynamically unstable patients were excluded. Outcomes of interest included progression of OPTX, mortality, complications (pneumonia, empyema), and length of stay in hospital and intensive care unit (ICU).

RESULTS

A total of 411 articles were identified. After applying the inclusion/exclusion criteria, 3 randomized trials enrolling a total of 101 patients were found to have acceptable quality standards suitable for analysis. The included studies did not reveal any significant difference between observation and TT in regards to progression of OPTX, risk of pneumonia, or length of stay in hospital or ICU. Mortality risk and empyema rate were also not different in the single studies that reported those outcomes.

CONCLUSION

The existing evidence leads to the conclusion that observation is at least as safe and effective as tube thoracostomy for management of occult pneumothorax.

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.

Occult pneumothorax in Chinese patients with significant blunt chest trauma: incidence and management

BACKGROUND

Occult pneumothorax (OP) is a pneumothorax not visualised on a supine chest X-ray (CXR) but detected on computed tomography (CT) scanning. With increasing CT use for trauma, more OP may be detected. Management of OP remains controversial, especially for patients undergoing mechanical ventilation. This study aimed to identify the incidence of OP using thoracic CT as the gold standard and describe its management amongst Hong Kong Chinese trauma patients.

METHODS

Analysis of prospectively collected trauma registry data. Consecutive significantly injured trauma patients admitted through the emergency department (ED) suffering from blunt chest trauma who underwent thoracic computed tomography (TCT) between in calendar years 2007 and 2008 were included. An OP was defined as the identification (by a specialist radiologist) of a pneumothorax on TCT that had not been previously detected on supine CXR.

RESULTS

119 significantly injured patients were included. 56 patients had a pneumothorax on CXR and a further 36 patients had at least one OP [OP incidence 30% (36/119)]. Bilateral OP was present in 8/36 patients, so total OP numbers were 44. Tube thoracostomy was performed for 8/44 OP, all were mechanically ventilated in the ED. The remaining 36 OP were managed expectantly. No patients in the expectant group had pneumothorax progression, even though 8 patients required subsequent ventilation in the operating room for extrathoracic surgery.

CONCLUSION

The incidence of OP (seen on TCT) in Chinese patients in Hong Kong after blunt chest trauma is higher than that typically reported in Caucasians. Most OP were managed expectantly without significant complications; no pneumothorax progressed even though some patients were mechanically ventilated.

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.

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.

Sonographic detection of pneumothorax by radiology residents as part of extended focused assessment with sonography for trauma

OBJECTIVE

The purpose of this study was to assess the accuracy of sonographic pneumothorax detection by radiology residents as a part of extended focused assessment with sonography for trauma (eFAST).

METHODS

In a prospective study, a sonographic search for pneumothoraces was performed as part of a standard FAST examination by the on-call resident. Each lung field was scanned at the second to fourth anterior intercostal spaces and the sixth to eighth midaxillary line intercostal spaces. A normal pleural interface was identified by the presence of parietal-over-visceral pleural sliding with "comet tail" artifacts behind. Absence of these normal features indicated a pneumothorax. The sonographic diagnosis was correlated with supine chest radiography and chest computed tomography (CT).

RESULTS

A total of 338 lung fields in 169 patients were included in the study. Patients underwent eFAST, chest radiography, and chest CT when clinically indicated. Chest CT was considered the reference standard examination. Computed tomography identified 43 pneumothoraces (13%): 34 small and 9 moderate. On chest radiography, 7 pneumothoraces (16%) were identified. Extended FAST identified 23 pneumothoraces (53%). Compared with CT, eFAST had sensitivity of 47%, specificity of 99%, a positive predictive value of 87%, and a negative predictive value of 93%. All of the moderate pneumothoraces were identified by eFAST. Twenty small pneumothoraces missed by eFAST did not require drainage during the hospitalization period.

CONCLUSIONS

Extended FAST performed by residents is an accurate and efficient tool for early detection of clinically important pneumothoraces.

The imaging of paediatric thoracic trauma

Major chest trauma in a child is associated with significant morbidity and mortality. It is most frequently encountered within the context of multisystem injury following high-energy trauma such as a motor vehicle accident. The anatomic-physiologic make-up of children is such that the pattern of ensuing injuries differs from that in their adult counterparts. Pulmonary contusion, pneumothorax, haemothorax and rib fractures are most commonly encountered. Although clinically more serious and potentially life threatening, tracheobronchial tear, aortic rupture and cardiac injuries are seldom observed. The most appropriate imaging algorithm is one tailored to the individual child and is guided by the nature of the traumatic event as well as clinical parameters. Chest radiography remains the first and most important imaging tool in paediatric chest trauma and should be supplemented with US and CT as indicated. Multidetector CT allows for the accurate diagnosis of most traumatic injuries, but should be only used in selected cases as its routine use in all paediatric patients would result in an unacceptably high radiation exposure to a large number of patients without proven clinical benefit. When CT is used, appropriate modifications should be incorporated so as to minimize the radiation dose to the patient whilst preserving diagnostic integrity.

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.

Delayed pneumothorax after stab wound to thorax and upper abdomen: Truth or myth?

BACKGROUND

Stab wounds to the thorax and upper abdomen have the potential to cause pneumothorax (PTX). When a CXR (CXR) obtained during initial resuscitation is negative, a second CXR (CXR-2) is commonly performed with the goal of identifying delayed PTX.

OBJECTIVES

To assess the diagnostic yield of the CXR-2 in identifying delayed PTX.

METHODS

Prospective observational study of patients (age >or=13 years) with stab wounds to the thorax (chest/back) and upper abdomen with suspected PTX, in a level 1 trauma centre. Patients were included if they had a negative initial CXR followed by a repeat CXR 3-6h after the initial one.

EXCLUSION CRITERIA

patients who died, were transferred out of the ED, or received chest tubes before the second CXR. The outcome of interest was delayed PTX. All CXR were read by an attending radiologist. To test the inter-observer agreement, another blinded radiologist reviewed 20% of CXR. Continuous data is presented as mean+/-standard deviation and categorical data as percentages with 95% confidence interval (CI). Kappa statistics were used to measure the inter-observer agreement between radiologists.

RESULTS

Between January 2003 and December 2006 a total of 185 patients qualified for the enrollment (mean age: 28+/-10 years, age range: 13-65, 94% male). Only 2 patients (1.1%, 95% CI, 0.4- 4.1%) had PTX on the CXR-2. Both patients received chest tubes. The inter-observer agreement for radiology reports was high (kappa: 0.79).

CONCLUSION

Occurrence of delayed PTX in patients with stab wounds to the thorax and upper abdomen and negative triage CXR is rare.

Incidência de pneumotórax residual após simpatectomia torácica videotoracoscópica com e sem drenagem pleural e sua possível influência na dor pós-operatória

OBJETIVO: Avaliar se o pneumotórax residual após simpatectomia torácica videotoracoscópica tem incidência diferente quando utilizada a drenagem pleural pós-operatória ou não e se este pneumotórax residual, quando presente, pode influenciar a dor pós-operatória até o 28º dia. MÉTODOS: Foram incluídos todos os pacientes com queixa de hiperidrose palmoplantar primária atendidos no Ambulatório de Cirurgia Torácica do Hospital Estadual Sumaré, de julho a dezembro de 2006. Todos foram submetidos à simpatectomia do terceiro gânglio torácico por videotoracoscopia e aleatorizados para receber ou não drenagem pleural pós-operatória por 3 h. Todos foram avaliados no pós-operatório imediato com radiogramas de tórax e tomografia computadorizada de tórax de baixa emissão de energia para detecção de pneumotórax residual. Foram avaliados quanto à dor pós-operatória em diferentes momentos até o 28º dia de pós-operatório, por meio de escala numérica visual e dosagem requerida de analgésicos opióides. RESULTADOS: Foram incluídos 56 pacientes neste estudo, 27 com drenagem pleural bilateral e 29 sem drenagem pleural. Não houve diferença estatística entre a incidência de pneumotórax residual após simpatectomia com e sem drenagem pleural. O pneumotórax residual, quando presente e diagnosticado por qualquer um dos métodos, não influenciou a dor pós-operatória até o 28º dia. CONCLUSÃO: Concluiu-se que a drenagem pleural tubular fechada, por um período de 3 h, no pós-operatório imediato de simpatectomia torácica videotoracoscópica, foi tão eficiente quanto a não drenagem, em relação à reexpansão pulmonar e à presença de pneumotórax residual. O pneumotórax residual, quando presente, não interferiu na dor pós-operatória até o 28º dia.

Pleural decompression and drainage during trauma reception and resuscitation

This review examines pleural decompression and drainage during initial hospital adult trauma reception and resuscitation, when it is indicated for haemodynamically unstable patients with signs of pneumothorax or haemothorax. The relevant historical background, techniques, complications and current controversies are highlighted. Key findings of this review are that: 1. Needle thoracocentesis is an unreliable means of decompressing the chest of an unstable patient and should only be used as a technique of last resort. 2. Blunt dissection and digital decompression through the pleura is the essential first step for pleural decompression, as decompression of the pleural space is a primary goal during reception of the haemodynamically unstable patient with a haemothorax or pneumothorax. Drainage and insertion of a chest tube is a secondary priority. 3. Techniques to prevent tube thoracostomy (TT) complications include aseptic technique, avoidance of trocars, digital exploration of the insertion site and guidance of the tube posteriorly and superiorly during insertion. 4. Whenever possible, blunt thoracic trauma patients should undergo definitive CT imaging after TT to check for appropriate tube position.

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).

Occult Pneumothorax in Trauma Patients: Development of an Objective Scoring System

BACKGROUND

The incidence of occult pneumothorax (OPTX) has dramatically increased since the widespread use of computed tomography (CT) scanning. The OPTX is defined as a pneumothorax not identified on plain chest X-ray but detected by CT scan. The overall reported incidence is about 5% to 8% of all trauma patients. We conducted a 5-year review of our OPTX incidence and asked if an objective score could be developed to better quantify the OPTX. This in turn may guide the practitioner with the decision to observe these patients.

METHODS

This is a retrospective review of all trauma patients in a Level I university trauma center during a 5-year period. The patients were identified by a query of all pneumothoraces in our trauma registry. Those X-ray results were then reviewed to identify those who had OPTX. After developing an OPTX score on a small number, we retrospectively scored 50 of the OPTXs by taking the largest perpendicular distance in millimeters from the chest wall of the largest air pocket. We then added 10 or 20 to this if the OPTX was either anterior/posterior or lateral, respectively.

RESULTS

A total of 21,193 trauma patients were evaluated and 1,295 patients with pneumothoraces (6.1%) were identified. Of the 1,295 patients with pneumothoraces, 379 (29.5%) OPTXs were identified. The overall incidence of OPTX was 1.8%: 95.7% occurred after blunt trauma, 222 (59%) of the OPTX patients had chest tubes and of the remaining 157 without chest tubes, 27 (17%) were on positive pressure ventilation. Of the 50 studies selected for scoring, the average score was 28.5. The average score for those with chest tubes was 34. The average score for those without chest tubes was 21. The positive predictive value for need of chest tube if the score was >30 was 78% and the negative predictive value if the score was <20 was 70%. Area under the receiver operator characteristic curve was 0.72, which was significant with p < 0.007.

CONCLUSIONS

The OPTX score could quantify the size of the OPTX allowing the practitioner to better define a "small" pneumothorax. The management of OPTX is not standardized and further study using a more objective classification may assist the surgeon's decision-making. The application of a scoring system may also decrease unnecessary insertion of chest tubes for small OPTXs and is currently being prospectively validated.

[Chest injury. Part II: Management of specific injuries]

Significant injuries to the thorax comprise pneumothorax, rib fractures, lung contusion, cardiac contusion, aortic laceration, ruptured diaphragm, and the very rare injuries to the tracheo-bronchial tree and the esophagus. A surgeon dealing with chest trauma patients needs to be familiar with the indications for and execution of chest tube insertion for thoracic drainage, pericardial puncture, and thoracoscopy and thoracotomy. Interventional techniques are gaining increasing acceptance in the management of major vascular injuries. The vast majority of patients with chest injury do not need an operative intervention, but it is necessary to place a thoracic drain in 10-15% of cases or to perform in a much lower proportion a pericardial puncture or a thoracotomy.

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.

Occult pneumothorax in trauma patients: should this be sought in the focused assessment with sonography for trauma examination?

OBJECTIVE

At present, CT scan is the gold standard for detecting occult traumatic pneumothorax not apparent on supine chest X-ray radiograph. Recently there were suggestions to expand focused assessment with sonography for trauma (FAST) to include thoracic ultrasound for detecting pneumothorax. The aim of the present study is to determine the incidence of occult pneumothorax (as shown by CT) in the subgroup of trauma patients undergoing FAST.

METHODS

Review of all trauma patients with FAST done from 1 June 2001 to 31 October 2002. Incidence of occult pneumothorax as diagnosed by CT was determined. Patients were not counted as having true occult pneumothorax if they had chest drains inserted before arrival or imaging studies. Selected clinical findings were tested for association with occult pneumothorax.

RESULTS

In total, 143 patients underwent FAST, of whom 137 (95.8%) had chest X-ray examination performed. Of the 137 patients 59 required CT abdomen and/or thorax. Occult pneumothorax was found in three patients (2.1%). A history of thorax and/or abdominal injury plus one or more of: (i) mechanisms potentially causing major trauma; (ii) abnormal chest examination; and (iii) chest X-ray radiograph abnormality in the absence of pneumothorax, was significantly associated with the presence of occult pneumothorax (P = 0.03, Fisher's exact test; sensitivity: 100%; specificity: 71%; likelihood ratio: 3.42).

CONCLUSION

The incidence of occult pneumothorax in the subgroup of trauma patients undergoing FAST is low. It implies that routine screening for its presence by adding thoracic ultrasound to FAST is unnecessary. Identifying those at risk of occult pneumothorax for further investigation appeared feasible.

Isolated computed tomography diagnosis of pulmonary contusion does not correlate with increased morbidity

BACKGROUND

Increased utilization of computed tomography (CT) has led to a rise in the diagnosis of pulmonary contusion. Its clinical significance, in the absence of findings on chest radiograph (CXR), has not been defined. This study examines the clinical course of patients with CT-only diagnosis of pulmonary contusion and compares it with that of patients with CXR-proven pulmonary contusion.

METHODS

The trauma database identified all children undergoing chest CT for blunt thoracic trauma during a 3-year period. Records were reviewed for age, mechanism of injury, Injury Severity Score (ISS), length of hospital stay (LOS), need for intensive care unit admission, and need for endotracheal intubation. A pediatric radiologist reviewed all films in a blinded fashion. Statistical analysis was performed using analysis of variance and Fisher's Exact test for 2 x 3 tables.

RESULTS

Eighty-two patients were identified. There were no CXR-positive, CT-negative cases. A CT diagnosis of pulmonary contusion was made in 46 patients. Of these, 31 had a contusion on CXR as well (CXR+ group) and 15 had a normal CXR (CT+ only group). Mean ISS score did not differ significantly between the two groups (27 +/- 12.3 and 22 +/- 10.3, respectively). Thirty-six patients had a normal CT (control). Mean LOS was significantly longer in the CXR+ group (13 +/- 12.0 days) than in the CT+ only and control groups (5 +/- 3.6 and 9 +/- 9.5 days, respectively; P < .01). The percentages of children requiring intensive care unit admission and intubation were also significantly higher in the CXR+ group.

CONCLUSION

The finding of pulmonary contusion by CT alone does not increase patient morbidity and appears to be of limited clinical significance.

Late-Onset Occult Pneumothorax After Lung Volume-Reduction Surgery

BACKGROUND

Lung volume-reduction surgery has proved to be a reliable palliative surgical treatment for patients with severe emphysema. Nonetheless, late complications can arise after lung volume-reduction surgery although this matter has been poorly investigated by previous studies.

METHODS

We report a series of 6 patients undergoing unilateral lung volume-reduction surgery at our institution between October 1995 and December 2004, who were readmitted several months after discharge because of the occurrence of occult pneumothorax mimicking acute respiratory failure.

RESULTS

Occult pneumothorax occurred in 3.3% of the 182 patients treated with lung volume-reduction surgery at our institution. Patients were readmitted after a mean of 94 days (range, 20 to 700 days) from the discharge. Chest roentgenography was unable to detect the occurrence of pneumothorax, which was instead revealed by means of a computed tomographic scan in all patients. The interval between admission and correct diagnosis averaged 22.4 hours. The number of air collections ranged between two and four. Treatment entailed solely blind chest drainage placement in 2 patients and awake video-assisted thoracoscopic surgery in the others, including placement of chest tube under direct vision in 1 patient, repair of lung tears by means of cyanoacrylate glue in 2 and bovine pericardium patch plus cyanoacrylate glue apposition in 1 patient.

CONCLUSIONS

In conclusion, we believe that occult pneumothorax should be kept in mind as one of the possible late complications of lung volume-reduction surgery and should be suspected whenever sudden worsening of dyspnea is noticed even in the presence of an uneventful chest roentgenogram. Awake video-assisted thoracoscopic surgery management can represent an effective option in these instances.

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.

Pneumothorax

Spontaneous pneumothoraces can occur without obvious underlying lung disease (primary) or in patients with known underlying lung disease (secondary). Management guidelines for spontaneous pneumothorax have been published by major professional organizations, but awareness and application among clinicians seems poor. First episodes of primary spontaneous pneumothorax can be managed with observation if the pneumothorax is small. If the pneumothorax is large or if the patient is symptomatic, manual aspiration via a small catheter or insertion of a small-bore catheter coupled to a Heimlich valve or water-seal device, should be performed. In general, definitive measures to prevent recurrence are recommended after the first recurrence of the pneumothorax, and can be achieved by medical (e.g. talc) or surgical (video-assisted thoracic surgery) pleurodesis. Secondary pneumothoraces should be treated with chest tube drainage followed by pleurodesis after the first episode to minimize any risk of recurrence. Traumatic pneumothoraces may be occult (not seen on an initial CXR) or non-occult. The majority are treated by placement of a chest tube. Selected patients may be treated conservatively, with approximately 10% of these patients eventually requiring chest tube placement. Iatrogenic pneumothoraces have a myriad of causes with transthoracic lung needle biopsy being most common. Transthoracic needle biopsy-related pneumothoraces have CT findings that can predict their occurrence and the need for chest tube placement. Iatrogenic pneumothoraces, regardless of cause, may be managed by observation or small bore chest tube placement, depending upon patient stability and the size of the pneumothorax.