Pneumothorax size: correlation of supine anteroposterior with erect posteroanterior chest radiographs

Deep Learning for Detecting Pneumothorax on Chest Radiographs after Needle Biopsy: Clinical Implementation

Background Accurate detection of pneumothorax on chest radiographs, the most common complication of percutaneous transthoracic needle biopsies (PTNBs), is not always easy in practice. A computer-aided detection (CAD) system may help detect pneumothorax. Purpose To investigate whether a deep learning-based CAD system can improve detection performance for pneumothorax on chest radiographs after PTNB in clinical practice. Materials and Methods A CAD system for post-PTNB pneumothorax detection on chest radiographs was implemented in an institution in February 2020. This retrospective cohort study consecutively included chest radiographs interpreted with CAD assistance (CAD-applied group; February 2020 to November 2020) and those interpreted before implementation (non-CAD group; January 2018 to January 2020). The reference standard was defined by consensus reading by two radiologists. The diagnostic accuracy for pneumothorax was compared between the two groups using generalized estimating equations. Matching was performed according to whether the radiograph reader and PTNB operator were the same using the greedy method. Results A total of 676 radiographs from 655 patients (mean age: 67 years ± 11; 390 men) in the CAD-applied group and 676 radiographs from 664 patients (mean age: 66 years ± 12; 400 men) in the non-CAD group were included. The incidence of pneumothorax was 18.2% (123 of 676 radiographs) in the CAD-applied group and 22.5% (152 of 676 radiographs) in the non-CAD group (P = .05). The CAD-applied group showed higher sensitivity (85.4% vs 67.1%), negative predictive value (96.8% vs 91.3%), and accuracy (96.8% vs 92.3%) than the non-CAD group (all P < .001). The sensitivity for a small amount of pneumothorax improved in the CAD-applied group (pneumothorax of <10%: 74.5% vs 51.4%, P = .009; pneumothorax of 10%-15%: 92.7% vs 70.2%, P = .008). Among patients with pneumothorax, 34 of 655 (5.0%) in the non-CAD group and 16 of 664 (2.4%) in the CAD-applied group (P = .009) required subsequent drainage catheter insertion. Conclusion A deep learning-based computer-aided detection system improved the detection performance for pneumothorax on chest radiographs after lung biopsy. © RSNA, 2022 See also the editorial by Schiebler and Hartung in this issue.

Conservative management of traumatic pneumothoraces: A retrospective cohort study

OBJECTIVE

Traumatic pneumothoraces (T-PTXs) are traditionally managed with an intercostal catheter (ICC), despite little evidence for this. Success with conservative management of primary spontaneous PTX has been demonstrated, and our ED has adopted a conservative approach where safe for all PTX.

METHODS

We reviewed all T-PTXs at our institution over a 7-year period to assess outcomes of those conservatively managed and compare with those who received an ICC. A total of 144 cases were identified, 65 managed conservatively and 79 invasively. Each was individually reviewed and variables including demographics, aetiology, smoking/lung disease history, T-PTX size (apical interpleural distance and hemithorax percentage), length of stay, Revised Trauma Score, Injury Severity Score and delayed intervention/complications were recorded. Chi-squared, Z-score, Mann-Whitney U and t-tests were used for analysis.

RESULTS

The mean apical interpleural distance was 26.8 mm (95% confidence interval [CI] 22.1-29.7 mm) in the conservative group and 49.1 mm (95% CI 41.2-57.0 mm) in the ICC group (P < 0.05 for difference between groups). Mean T-PTX percentage 25.9% (95% CI 22.1-29.7%) in the conservative group versus 45.9% (95% CI 39.7-50.5%) in the ICC group (P < 0.05 for difference between two groups) and mean Revised Trauma Score 7.4 (conservative) versus 6.8 (invasive) (P < 0.05). No conservatively managed patient required a delayed intervention for their T-PTX, and 2 of 79 (3%) patients in the ICC group had a complication (one infection, one haemothorax).

CONCLUSION

Our data support conservative management of selected T-PTXs and shows a need for a prospective randomised trial to further examine this intervention.

End-Tidal Carbon Dioxide Monitoring for Spontaneous Pneumothorax

Background

Spontaneous pneumothorax should be classified as primary spontaneous pneumothorax (PSP) or secondary spontaneous pneumothorax (SSP) because treatment strategies may differ depending on underlying lung conditions and clinical course. The pulmonary dysfunction can lead to changes in end-tidal carbon dioxide (ETCO₂). The aim of this study was to investigate the difference in ETCO₂ between PSP and SSP.

Methods

This retrospective observational study included adult patients diagnosed with spontaneous pneumothorax in the emergency room from April 2019 to September 2020. We divided patients into PSP and SSP groups and compared ETCO₂ variables between the two groups.

Results

There were 33 (66%) patients in the PSP group and 17 (34%) patients in the SSP group. Initial ETCO₂ was lower in the SSP group than in the PSP group (30 (23–33) vs. 35 (33–38) mmHg, p=0.002). Multivariate analysis revealed that respiratory gas associated with SSP was initial ETCO₂ (OR: 0.824; 95% CI: 0.697–0.974, p=0.023). The optimal cutoff for initial ETCO₂ to detection of SSP was 32 mmHg (area under curve, 0.754), with 76.5% sensitivity and 72.7% specificity.

Conclusion

ETCO₂ monitoring is a reliable noninvasive indicator of differentiating between PSP and SSP. Initial ETCO₂ lower than 32 mmHg is a predictor of SSP.

Analysis of Pneumothorax in Noninvasive Ventilator Users With Duchenne Muscular Dystrophy

BACKGROUND

With the advancement of cardiorespiratory interventions, the survival rate among patients with Duchenne muscular dystrophy (DMD) has increased. Subsequently, pneumothorax has become a significant problem in patients with prolonged ventilatory support.

RESEARCH QUESTION

What are the frequency, recurrence rate, risk factors, and prognosis of pneumothorax in patients with DMD requiring noninvasive ventilation (NIV)? Also, are there known risk factors of pneumothorax on chest CT scans?

STUDY DESIGN AND METHODS

This retrospective longitudinal cohort study included 176 patients treated between 2006 and 2019. We collected information regarding location, severity, treatment methods, recurrence frequency, abnormal findings on CT scanning, and date of death. We compared the pneumothorax and nonpneumothorax groups. We calculated the estimated survival probabilities from the age at NIV application according to pneumothorax occurrence.

RESULTS

Sixteen of the 176 patients (9.0%) experienced pneumothorax (median age at diagnosis, 24.6 years; range, 20.7-33.7 years). Among the 16 patients, 15 demonstrated pneumothorax after NIV application (median time between diagnosis and initial NIV application, 5.6 years; range, 3 days-9.6 years). Sixteen patients experienced 31 episodes of pneumothoraces (range, one-five episodes); among them, seven episodes (22.6%) were asymptomatic. Known risk factors not clearly visible by radiography scans were found in chest CT scan in 11 patients (68.8%). Seven of 16 patients (43.8%) eventually sustained severe lung damage with pulmonary fibrosis. No significant between-group differences were found in body weight, BMI, and age at NIV application; however, the pneumothorax group showed a significantly higher mortality rate after NIV application.

INTERPRETATION

On pneumothorax occurrence in patients with DMD, recurrences and severe lung damage are common; moreover, these patients show higher mortality rates than patients without pneumothorax. Chest CT scans should be performed to identify risk factors, and treatment should be initiated accordingly. In addition, physicians should consider chest CT scanning in the case of suspected pneumothorax, even if no radiographic abnormality is found.

Deep learning algorithm for surveillance of pneumothorax after lung biopsy: a multicenter diagnostic cohort study

OBJECTIVES

Pneumothorax is the most common and potentially life-threatening complication arising from percutaneous lung biopsy. We evaluated the performance of a deep learning algorithm for detection of post-biopsy pneumothorax in chest radiographs (CRs), in consecutive cohorts reflecting actual clinical situation.

METHODS

We retrospectively included post-biopsy CRs of 1757 consecutive patients (1055 men, 702 women; mean age of 65.1 years) undergoing percutaneous lung biopsies from three institutions. A commercially available deep learning algorithm analyzed each CR to identify pneumothorax. We compared the performance of the algorithm with that of radiology reports made in the actual clinical practice. We also conducted a reader study, in which the performance of the algorithm was compared with those of four radiologists. Performances of the algorithm and radiologists were evaluated by area under receiver operating characteristic curves (AUROCs), sensitivity, and specificity, with reference standards defined by thoracic radiologists.

RESULTS

Pneumothorax occurred in 17.5% (308/1757) of cases, out of which 16.6% (51/308) required catheter drainage. The AUROC, sensitivity, and specificity of the algorithm were 0.937, 70.5%, and 97.7%, respectively, for identification of pneumothorax. The algorithm exhibited higher sensitivity (70.2% vs. 55.5%, p < 0.001) and lower specificity (97.7% vs. 99.8%, p < 0.001), compared with those of radiology reports. In the reader study, the algorithm exhibited lower sensitivity (77.3% vs. 81.8-97.7%) and higher specificity (97.6% vs. 81.7-96.0%) than the radiologists.

CONCLUSION

The deep learning algorithm appropriately identified pneumothorax in post-biopsy CRs in consecutive diagnostic cohorts. It may assist in accurate and timely diagnosis of post-biopsy pneumothorax in clinical practice.

KEY POINTS

• A deep learning algorithm can identify chest radiographs with post-biopsy pneumothorax in multicenter consecutive cohorts reflecting actual clinical situation. • The deep learning algorithm has a potential role as a surveillance tool for accurate and timely diagnosis of post-biopsy pneumothorax.

Determinants of the esophageal-pleural pressure relationship in humans

Esophageal pressure has been suggested as adequate surrogate of the pleural pressure. We investigate after lung surgery the determinants of the esophageal and intrathoracic pressures and their differences. The esophageal pressure (through esophageal balloon) and the intrathoracic/pleural pressure (through the chest tube on the surgery side) were measured after surgery in 28 patients immediately after lobectomy or wedge resection. Measurements were made in the nondependent lateral position (without or with ventilation of the operated lung) and in the supine position. In the lateral position with the nondependent lung, collapsed or ventilated, the differences between esophageal and pleural pressure amounted to 4.4 ± 1.6 and 5.1 ± 1.7 cmH₂O. In the supine position, the difference amounted to 7.3 ± 2.8 cmH₂O. In the supine position, the estimated compressive forces on the mediastinum were 10.5 ± 3.1 cmH₂O and on the iso-gravitational pleural plane 3.2 ± 1.8 cmH₂O. A simple model describing the roles of chest, lung, and pneumothorax volume matching on the pleural pressure genesis was developed; modeled pleural pressure = 1.0057 × measured pleural pressure + 0.6592 (r² = 0.8). Whatever the position and the ventilator settings, the esophageal pressure changed in a 1:1 ratio with the changes in pleural pressure. Consequently, chest wall elastance (E_cw) measured by intrathoracic (E_cw = ΔPpl/tidal volume) or esophageal pressure (E_cw = ΔPes/tidal volume) was identical in all the positions we tested. We conclude that esophageal and pleural pressures may be largely different depending on body position (gravitational forces) and lung-chest wall volume matching. Their changes, however, are identical.NEW & NOTEWORTHY Esophageal and pleural pressure changes occur at a 1:1 ratio, fully justifying the use of esophageal pressure to compute the chest wall elastance and the changes in pleural pressure and in lung stress. The absolute value of esophageal and pleural pressures may be largely different, depending on the body position (gravitational forces) and the lung-chest wall volume matching. Therefore, the absolute value of esophageal pressure should not be used as a surrogate of pleural pressure.

Pneumothorax size measurements on digital chest radiographs: Intra- and inter- rater reliability

PURPOSE

Detailed and reliable methods may be important for discussions on the importance of pneumothorax size in clinical decision-making. Rhea's method is widely used to estimate pneumothorax size in percent based on chest X-rays (CXRs) from three measure points. Choi's addendum is used for anterioposterior projections. The aim of this study was to examine the intrarater and interrater reliability of the Rhea and Choi method using digital CXR in the ward based PACS monitors.

MATERIALS AND METHODS

Three physicians examined a retrospective series of 80 digital CXRs showing pneumothorax, using Rhea and Choi's method, then repeated in a random order two weeks later. We used the analysis of variance technique by Eliasziw et al. to assess the intrarater and interrater reliability in altogether 480 estimations of pneumothorax size.

RESULTS

Estimated pneumothorax sizes ranged between 5% and 100%. The intrarater reliability coefficient was 0.98 (95% one-sided lower-limit confidence interval C 0.96), and the interrater reliability coefficient was 0.95 (95% one-sided lower-limit confidence interval 0.93).

CONCLUSION

This study has shown that the Rhea and Choi method for calculating pneumothorax size has high intrarater and interrater reliability. These results are valid across gender, side of pneumothorax and whether the patient is diagnosed with primary or secondary pneumothorax.

Semi-quantification of pneumothorax volume by lung ultrasound

BACKGROUND

Lung ultrasound (LUS) may accurately diagnose pneumothorax. However, there is uncertainty about its usefulness in the quantification of pneumothorax size. To determine the ability of LUS in the semi-quantification of pneumothorax volume, we compared the projection of the lung point (LP) with the pneumothorax volume measured by computerized tomography (CT) and the interpleural distance on chest radiography (CXR).

METHODS

We performed LUS in patients with pneumothorax and all the LP located on the chest wall were compared to CXR and CT studies. The primary outcome of the study was the ability of LP to grade pneumothorax volumes measured by CT. The secondary outcome was the accuracy of LP to predict small and large pneumothorax according to the societal guidelines based on CXR reading.

RESULTS

A total of 124 patients with pneumothorax were enrolled (76 spontaneous, 20 traumatic and 28 post-procedural). Ninety-four CXR and 58 CT were available for the analysis. An LP posterior to the mid axillary line corresponded to three different CXR criteria for large pneumothorax with sensitivity from 81.4 to 88.2 % and specificity from 64.7 to 72.6 %. The mid axillary line also represented the limit for predicting greater than 15 % of lung collapse when volume is measured at CT, with sensitivity 83.3 % and specificity 82.4 %.

CONCLUSIONS

LUS-targeted assessment of LP was a useful predictor of pneumothorax volume in this research study setting. LUS reliably classified pneumothorax size when compared to criteria based on CXR reading, particularly the small sized pneumothorax. However, LUS greatly outperformed conventional CXR reading for a graded quantification of the percentage of lung collapse.

Magnetic compression in gastrointestinal and bilioenteric anastomosis: how much force?

AIM

The concept of compression alimentary anastomosis is well established. Recently, magnetic axial alignment pressures have been encompassed within such device constructs. We quantify the magnetic compression force and pressure required to successfully achieve gastrointestinal and bilioenteric anastomosis by in-depth interrogation of the reported literature.

METHODS

Reports of successful deployment and proof of anastomotic patency on survival were scrutinized to quantify the necessary dimensions and strengths of magnetic devices in (a) gastroenteral anastomosis in live porcine models and (b) bilioenteric anastomosis in the clinical setting. Using a calculatory tool developed for this work (magnetic force determination algorithm, MAGDA), ideal magnetic force and compression pressure were quantified from successful reports with regard to their variance by intermagnet separation.

RESULTS

Optimized ranges for both compression force and pressure were determined for successful porcine gastroenteral and clinical bilioenteric anastomoses. For gastroenteral anastomoses (porcine investigations), an optimized compression force between 2.55 and 3.57 kg at 2-mm intermagnet separation is recommended. The associated compression pressure should not exceed 60 N/cm(2). Successful bilioenteric anastomoses is best clinically achieved with intermagnet compression of 18 to 31 g and associated pressures between 1 and 3.5 N/mm(2) (at 2-mm intermagnet separation).

CONCLUSION

The creation of magnetic compression anastomoses using permanent magnets demonstrates a remarkable resilience to variations in magnetic force and pressure exertion. However, inappropriate selection of compression characteristics and magnet dimensions may incur difficulties. Recommendations of this work and the availability of the free online tool (http://magda.ucc.ie/) may facilitate a factor of robustness in the design and refinement of future devices.

The frequency of reexpansion pulmonary edema after trocar and hemostat assisted thoracostomy in patients with spontaneous pneumothorax

PURPOSE

Several risk factors for development of reexpansion pulmonary edema (REPE) after drainage of pneumothoraces have been reported, but the association between the method of thoracostomy and the development of REPE is unknown. The aim of this study was to compare the frequency of REPE after treatment of spontaneous pneumothorax with trocar or hemostat assisted closed thoracostomy.

MATERIALS AND METHODS

We performed a prospective, observational study including 173 patients with spontaneous pneumothorax who visited the emergency department from January 2007 to December 2008. In 2007, patients were treated with hemostat-assisted drainage, whereas patients in 2008 were treated with trocar-assisted drainage. The main outcome was the development of REPE, determined by computed tomography of the chest 8 hours after closed thoracostomy. Outcomes in both groups were compared using univariate and multivariate analyses.

RESULTS

Ninety-two patients were included, 48 (42 males) of which underwent hemostat-assisted drainage and 44 (41 males) underwent trocar-assisted drainage. The groups were similar in mean age (24 ± 10 vs. 26 ± 14 respectively). The frequencies of REPE after hemostat- and trocar-assisted drainage were 63% (30 patients) and 86% (38 patients) respectively (p=0.009). In multivariate analysis, trocar-assisted drainage was the major contributing factor for developing REPE (odds ratio=5.7, 95% confidence interval, 1.5-21). Age, gender, size of pneumothorax, symptom duration and laboratory results were similar between the groups.

CONCLUSION

Closed thoracostomy using a trocar is associated with an increased risk of REPE compared with hemostat- assisted drainage in patients with spontaneous pneumothorax.

Principles of diagnosis and management of traumatic pneumothorax

Presence of air and fluid with in the chest might have been documented as early as Fifth Century B.C. by a physician in ancient Greece, who practiced the so-called Hippocratic succession of the chest. This is due to a development of communication between intrapulmonary air space and pleural space, or through the chest wall between the atmosphere and pleural space. Air enters the pleural space until the pressure gradient is eliminated or the communication is closed. Increasing incidence of road traffic accidents, increasing awareness of healthcare leading to more advanced diagnostic procedures, and increasing number of admissions in intensive care units are responsible for traumatic (noniatrogenic and iatrogenic) pneumothorax. Clinical spectrum of pneumothorax varies from asymptomatic patient to life-threatening situations. Diagnosis is usually made by clinical examination. Simple erect chest radiograph is sufficient though; many investigations are useful in accessing the future line of action. However, in certain life-threatening conditions obtaining imaging studies can causes an unnecessary and potential lethal delay in treatment.

New classification and clinical characteristics of reexpansion pulmonary edema after treatment of spontaneous pneumothorax

OBJECTIVE

Reexpansion pulmonary edema (REPE) is a rare yet sometimes fatal complication associated with the treatment of lung diseases such as pleural effusion, pneumothorax, and hemothorax. The current study summarizes our experience with REPE for a 3-year period.

METHODS

We prospectively collected demographic and clinical data on consecutive patients presenting to an academic university-based emergency department with spontaneous pneumothorax that was treated with closed thoracostomy for a 3-year period.

RESULTS

Eighty-four study patients were enrolled between December 2002 and September 2005. Reexpansion pulmonary edema developed in 25 of 84 (29.8% [95% confidence interval, 21.0-40.2]) patients. Many cases of REPE were small and asymptomatic and only diagnosed on computed tomography of the chest. There was only one death (1.2% [95% confidence interval, A to B]). Reexpansion pulmonary edema was associated with patients with larger pneumothoraces without fibrotic changes and with patients with hypoxia and fibrotic changes. Classic REPE as seen on chest radiograph was 16 (19.0%) in 84 patients. Diffuse REPE as seen only on computed tomography and involved more than 1 lobe was 1 (1.2%) in 84 patients. Isolated REPE as seen only on computed tomography and limited to lesser than 1 lobe was 8 (9.5%) in 84 patients.

CONCLUSIONS

The rate of REPE after tube thoracostomy of spontaneous pneumothorax is greater than previously reported and often asymptomatic. The risk of developing REPE is greater with larger pneumothorax, especially in patients without fibrotic lung changes, and with hypoxia in patients with fibrotic changes.

Ultrasound in the surgical intensive care unit

PURPOSE OF REVIEW

Critically ill patients are subjected to a variety of diagnostic and therapeutic procedures. It is desirable to make these interventions as timely, safe, and effective as possible. Bedside ultrasound and echocardiography are tools that allow for diagnosis of many conditions, without subjecting the patient to radiation, dye, and the risks of transport. In addition, ultrasound guidance of procedures may improve safety and efficacy. This review analyzes the literature on ultrasound and echocardiography use in the ICU.

RECENT FINDINGS

There is evidence supporting the use of bedside echocardiography and ultrasound for the diagnosis of chest, abdominal, and other pathologic conditions in the ICU. There is also evidence to support ultrasound guidance of vascular access and other procedures. There are multiple reports of novel uses of bedside echocardiography and ultrasound in the ICU.

SUMMARY

There is substantial literature supporting ultrasound and bedside limited echocardiography in the critical care setting. In addition, there are frequent reports of new applications for these technologies in the literature. The role of ultrasound and bedside limited echocardiography in the critical care setting is likely to expand in the future and become a part of daily care in every surgical intensive care unit.

The accuracy of thoracic ultrasound for detection of pneumothorax is not sustained over time: a preliminary study

BACKGROUND

Ultrasound has proven to be very accurate in the diagnosis of pneumothorax in the trauma suite. It is unknown whether this accuracy is maintained over time in patients with a thoracostomy (TT) in place.

METHODS

Hospitalized patients with a TT placed to treat a traumatic pneumothorax underwent serial daily bedside surgeon-performed ultrasound by 1 of 2 experienced surgeon sonographers who were unaware of concomitant X-ray findings. Results were compared with daily chest X-ray films. Data collected included size and day of placement of the chest tube, as well as the results of the serial ultrasounds and the comparative X-ray films.

RESULTS

Fourteen patients (78% men, mean age 33 years) sustained traumatic pneumothorax. The causes included stab wound (9), gunshot wound (3), and rib fracture (2). They underwent 126 (median 7) ultrasound evaluations and were followed between 4 and 26 (median 7) days after injury. Of these exams, 95 had a concomitant chest X-ray film within 1 hour of the ultrasound, thus 190 hemithoraces could be analyzed. Eighty-two ultrasounds were performed for hemithoraces that had no injury or TT in place and all 82 revealed normal pleural sliding. No pneumothoraces were noted on concomitant chest X-ray films (100% accuracy). One hundred eight ultrasounds were performed for hemithoraces that had a TT in place. For the first 24 hours, accuracy remained 100%. After 24 hours, however, sensitivity of ultrasound diagnosis of pneumothorax fell to 55%, specificity fell to 70%, positive predictive value to 43%, and negative predictive value to 79%. This led to an overall accuracy rate for ultrasound examination after 24 hours of 65%.

CONCLUSIONS

Ultrasound evaluation for pneumothorax is very accurate for the first 24 hours after insertion of a TT, but the accuracy, especially the positive predictive value, is not sustained over time, possibly as a result of the formation of intrapleural adhesions.

The management of chest tubes in patients with a pneumothorax and an air leak after pulmonary resection

BACKGROUND

Placing chest tubes to water seal is superior for patients with an air leak, but when a patient has a pneumothorax and an air leak the best chest tube setting is unknown.

METHODS

This is a retrospective analysis of a prospective database on a consecutive series of patients who had a pneumothorax and air leak on the same day. Patients underwent elective pulmonary resection by one surgeon and had their chest tubes placed to water seal on postoperative day 1. Daily chest radiographs were obtained, and the size of the pneumothorax and air leak were measured. Tubes were left on seal unless there was a symptomatic enlarging pneumothorax or subcutaneous emphysema (defined as failing water seal). The primary objective was to evaluate the efficacy of water seal. We also wanted to identify risk factors that predicted failure of water seal.

RESULTS

There were 838 patients > or = 21 years old who underwent elective pulmonary resection, and 86 patients (10%) had an air leak and a concomitant pneumothorax on the same day. Fourteen patients (16%) failed water seal. Multivariate analysis showed that a large air leak (greater than or equal to expiratory 3 in our classification system; odds ratio [OR], 16.5; p < 0.001) and a pneumothorax > 8 cm in size (OR, 4.9; p < 0.005) were predictors of failing water seal.

CONCLUSIONS

Keeping chest tubes on water seal is safe for most patients with an air leak and a pneumothorax. However, if the leak or pneumothorax is large, then subcutaneous emphysema or an expanding symptomatic pneumothorax is more likely. A prospective randomized trial is needed to compare water seal to suction in these patients.

Risk factors for pneumothorax and bleeding after CT-guided percutaneous coaxial cutting needle biopsy of lung lesions

PURPOSE

To evaluate risk factors for pneumothorax and bleeding after computed tomography (CT)-guided percutaneous coaxial cutting needle biopsy of lung lesions.

MATERIALS AND METHODS

This study involved 117 consecutive patients with 117 intrapulmonary lesions. Statistical analysis of factors related to patient characteristics, lung lesions, and biopsy technique was performed to determine possible contribution to the occurrence of pneumothorax and bleeding. Interactions between related factors were considered to prevent colinearity.

RESULTS

Pneumothorax occurred in 12% (14 of 117) of patients. Needle aspiration of two moderate asymptomatic pneumothoraces were performed; there was no chest tube insertion. Lesion depth (P =.0097), measured from the pleural puncture site to the edge of the intrapulmonary lesion along the needle path, was the single significant predictor of pneumothorax. The highest risk of pneumothorax occurred in subpleural lesions 2 cm or shorter in depth (this represented 33% of lung lesions but caused 71% of all pneumothoraces; OR = 7.1; 95% CI, 1.3-50.8). Bleeding presented as lung parenchyma hemorrhage and hemoptysis in 30 patients (26%). Hemoptysis occurred in four patients (3%). Univariate analysis identified lesion depth (P <.0001), lesion size (P <.015), and pathology type (P =.007) as risk factors for bleeding. Multivariate logistic regression analysis identified lesion depth as the most important risk factor, with the highest bleeding risk for lesions more than 2 cm deep (14% of lesions caused 46% of all bleeding; OR = 17.3; 95% CI, 3.3-121.4).

CONCLUSIONS

In CT-guided coaxial cutting needle biopsy, lesion depth is the single predictor for risk of pneumothorax, which occurs at the highest rate in subpleural lesions. Increased risk of bleeding occurs in lesions deeper than 2 cm.

A treatment algorithm for pneumothoraces complicating central venous catheter insertion

BACKGROUND

We investigated the role of observation or insertion of a small French pigtail catheter with Heimlich valve as alternative management to a tube thoracostomy for iatrogenic pneumothorax complicating central venous catheter (CVC) insertion.

METHODS

A retrospective review of 9,637 consecutive patients who had had subclavian CVCs inserted on an outpatient basis identified 100 patients with pneumothoraces. Treatment consisted of (1) observation, (2) outpatient insertion of a Heimlich valve, or (3) inpatient tube thoracostomy.

RESULTS

The median pneumothorax size was 10% (range 1% to 100%). Fifty-eight patients had observation as initial treatment, and this strategy was successful in 35 (60%). Thirty-four patients were treated initially with Heimlich valves, and this strategy was successful in 29 (85%). Tube thoracostomy as initial therapy was successful in 7 (88%) of 8 patients. Patients in who initial treatment failed were treated with insertion of a Heimlich valve or tube thoracostomy.

CONCLUSION

In appropriately selected patients, pneumothorax after insertion of a subclavian CVC can be successfully managed in the outpatient setting with observation. Patients in whom observation fails can be treated with insertion of a Heimlich valve. Tube thoracostomy can be reserved for refractory PTX or emergent situations.