Medical and surgical management of pneumothorax in diving and hyperbaric chambers.

The presence of a pneumothorax within a pressurized chamber represents unique diagnostic and management challenges. This is particularly the case in the medical and geographic remoteness of many chamber locations. Upon commencing chamber decompression, unvented intrapleural air expands. If its initial volume and/or degree of chamber pressure reduction is significant enough, a tension pneumothorax will result. Numerous reports chronicle failure to diagnose and manage in-chamber pneumothorax with resultant morbidity and one fatal outcome. Such cases have occurred in both medically remote and clinically based settings. This paper reviews pneumothorax and tension pneumothorax risk factors and clinical characteristics. It suggests primary medical management using the principle of oxygen-induced inherent unsaturation in concert with titrated chamber decompression designed to prevent intrapleural air expanding faster than it contracts. Should this conservative approach prove unsuccessful, and surgical venting becomes necessary or otherwise immediately indicated, interventional options are reviewed.

Pneumothorax during manned chamber operations: A summary of reported cases.

In-chamber pneumothorax has complicated medically remote professional diving operations, submarine escape training, management of decompression illness, and hospital-based provision of hyperbaric oxygen therapy. Attempts to avoid thoracotomy by combination of high oxygen partial pressure breathing (the concept of inherent unsaturation) and greatly slowed rates of chamber decompression proved successful on several occasions. When this delicate balance designed to prevent the intrapleural gas volume from expanding faster than it contracts proved futile, chest drains were inserted. The presence of pneumothorax was misdiagnosed or missed altogether with disturbing frequency, resulting in wide-ranging clinical consequences. One patient succumbed before the chamber had been fully decompressed. Another was able to ambulate unaided from the chamber before being diagnosed and managed conventionally. In between these two extremes, patients experienced varying degrees of clinical compromise, from respiratory distress to cardiopulmonary arrest, with successful resuscitation. Pneumothorax associated with manned chamber operations is commonly considered to develop while the patient is under pressure and manifests during ascent. However, published reports suggest that many were pre-existing prior to chamber entry. Risk factors included pulmonary barotrauma-induced cerebral arterial gas embolism, cardiopulmonary resuscitation, and medical or surgical procedures usually involving the lung. This latter category is of heightened importance to hyperbaric operations as an iatrogenically induced pneumothorax may take as long as 24 hours to be detected, perhaps long after a patient has been cleared for chamber exposure.

Pneumothorax, pneumomediastinum and subcutaneous emphysema as respiratory complications of COVID-19.

BACKGROUND: Pneumothorax, pneumomediastinum and subcutaneous emphysema are respiratory complications of Coronavirus disease 2019 occurring with noteworthy frequency in patients especially with severe disease. They can be life-threatening and often complicate patient managment. METHODS: This was a retrospective, observational study of patients admitted in Nepal Armed Police Force hospital from 13/05/2020 to 28/12/2021 diagnosed with pneumothorax, pneumomediastinum or subcutaneous emphysema singly or in combination. Data were collected from clinical charts, imaging records and electronic medical records of Severe Acute Respiratory Syndrome Coronavirus-type 2 positive patients 18 years and older. The frequency and type of the defined complications, the inflammatory markers and ventilatory parameters just prior to their diagnosis, the duration of hospitalization and ICU admission and in-hospital mortality rate were studied. RESULTS: Out of 4013 COVID-19 patients admitted in the hospital during the period, a total of 28 patients were observed to develop the complications, the overall incidence being 0.7% among hospitalized patients and 5.6% among ICU patients. The proportion of subcutaneous emphysema (64.3%) was highest followed by pneumomediastinum (46.4%) and then pneumothorax (39.3%) existing singly or in combination among the 28 patients, where four patients developed the complications spontaneously. Mean Positive End Expiratory Pressure of 12.1±2.6 cmH2O and Peak Inspiratory Pressure or Pressure Support of 30.9±10.3 cmH2O were observed for patients under positive pressure ventilation. Most of the patients who developed the complications (78.6%) died during treatment. CONCLUSIONS: Pulmonary air leak complications occur frequently in COVID-19 patients treated with or without positive pressure ventilation signifying increased disease severity, risk of ICU admission and high mortality rate. Hence, clinicians should be vigilant of these complications in all patients affected with COVID-19 and institute timely management.

The sensitivity of a neck CT scan in detecting pneumothoraces in nonpenetrating trauma.

BACKGROUND: The trauma-related pneumothorax is a common intrathoracic injury and can go undetected with detrimental outcomes. Chest computed tomography (CT) investigation in low- to middle-income countries (LMIC) is not always readily available during emergency situations and increased workloads. However, alternative investigations all have limitations in including pneumothoraces. Patients may have trauma indications for CT of the head and neck. The neck CT scan may hold an extra potential advantage in pneumothorax detection. This study aimed to assess its sensitivity in pneumothorax detection in nonpenetrating trauma. METHODS: A retrospective study was conducted from 1 January 2016 to 31 December 2021. All adult patients sustaining nonpenetrating injuries, and investigated with chest and neck CT scans were included. The chest CT scan was the gold standard against,which the neck CT scan was compared to determine the accuracy of pneumothorax detection. Stata version 16 was used for descriptive statistical analysis, and a p-value of 0.05 was considered statistically significant. RESULTS: One thousand ninety three were eligible for evaluation; 204 (18.66%) pneumothoraces were detected on chest CT scans, 200 (98.0%) of which were also detected on the neck CT scan, producing a sensitivity of 98.0% (95% CI 95.1-99.5%) and a specificity of 100% (95% CI 99.6-100%). Most pneumothoraces were detected at T1 level (45.09%), followed by T2 (43.62%). CONCLUSION: The neck CT scan has demonstrated high sensitivity and specificity in pneumothorax detection. Thus, it may be used as an additional tool for those who could not receive or do not need a formal chest CT but have an indication for neck CT scans.

[Analysis of Influencing Factors of Complications for CT-guided 
Percutaneous Lung Biopsy].

BACKGROUND: Computed tomography guided percutaneous lung biopsy (CT-PLB) is a widely used method for the diagnosis of lung lesions. However, it is invasive, and the most common complications are pneumothorax and pulmonary hemorrhage, which can be life-threatening in severe cases. Therefore, the aim of this study is to analyze the independent risk factors affecting the occurrence of different complications of CT-PLB, so as to reduce the incidence of complications. METHODS: The 605 patients with complete clinical data who underwent CT-PLB in our hospital from May 2018 to December 2019 were retrospectively analyzed. According to the location of the lesions, they were divided into subpleural group and non-subpleural group. The patients were divided into pneumothorax group, pulmonary hemorrhage group, pneumothorax with pulmonary hemorrhage group and non-pneumothorax/pulmonary hemorrhage group according to the complications. The risk factors affecting the incidence of different complications and the independent risk factors of each complication were analyzed. RESULTS: The incidence of pneumothorax was 34.1%, the incidence of pulmonary hemorrhage was 28.1%, and the incidence of pneumothorax complicated with pulmonary hemorrhage was 10.8% (63 cases). The independent risk factor affecting the incidence of subpleural pneumothorax was lesion size (P=0.002). The independent risk factors affecting the occurrence of pneumothorax in the non-subpleural group were plain scan CT value (P=0.035), length of needle through lung tissue (P=0.003), and thickness of needle through chest wall (P=0.020). Independent risk factors affecting the occurrence of pulmonary hemorrhage in the non-subpleural group were length of needle through lung tissue (P<0.001), △CT value of needle travel area (P=0.001), lesion size (P=0.034) and body position (P=0.014). The independent risk factors affecting the co-occurrence of pneumothorax and pulmonary hemorrhage were the length of needle through lung tissue (P<0.001) and the △CT value of needle travel area (P<0.001). CONCLUSIONS: CT-PLB is a safe and effective diagnostic method, which of high diagnostic value for lung lesions. Selecting the appropriate puncture program can reduce complications such as pneumothorax and pulmonary hemorrhage, and improve diagnosis and treatment efficiency.

Endobronchial valves for emphysema and persistent air-leak: 10-year experience in an Asian country.

BACKGROUND: Endobronchial valve (EBV) therapy, a validated method for bronchoscopic lung volume reduction (BLVR) in severe emphysema, has been explored for persistent air-leak (PAL) management. However, its effectiveness and safety in the Asian population require further real-world evaluation. In this study, we assessed the outcomes of treatment with EBV within this demographic. METHODS: We conducted a retrospective analysis of medical records from 11 Korean centers. For the emphysema cohort, inclusion criteria were patients diagnosed with emphysema who underwent bronchoscopy intended for BLVR. We assessed these patients for clinical outcomes of chronic obstructive pulmonary disease. All patients with PAL who underwent treatment with EBV were included. We identified the underlying causes of PAL and evaluated clinical outcomes after the procedure. RESULTS: The severe emphysema cohort comprised 192 patients with an average age of 70.3 years, and 95.8% of them were men. Ultimately, 137 underwent treatment with EBV. Three months after the procedure, the BLVR group demonstrated a significant improvement in forced expiratory volume in 1 s (+160 mL vs. +30 mL; P = 0.009). Radiographic evidence of lung volume reduction 6 months after BLVR was significantly associated with improved survival (adjusted hazard ratio 0.020; 95% confidence interval 0.038-0.650; P = 0.010). Although pneumothorax was more common in the BLVR group (18.9% vs. 3.8%; P = 0.018), death was higher in the no-BLVR group (38.5% vs. 54.5%, P = 0.001), whereas other adverse events were comparable between the groups. Within the subset of 18 patients with PAL, the predominant causes of air-leak included spontaneous secondary pneumothorax (44.0%), parapneumonic effusion/empyema (22.2%), and post-lung resection surgery (16.7%). Following the treatment, the majority (77.8%) successfully had their chest tubes removed. Post-procedural complications were minimal, with two incidences of hemoptysis and one of empyema, all of which were effectively managed. CONCLUSIONS: Treatment with EBV provides substantial clinical benefits in the management of emphysema and PAL in the Asian population, suggesting a favorable outcome for this therapeutic approach.

An 88-Year-Old Woman With Pneumothorax and Black Pleural Effusion.

CASE PRESENTATION: An 88-year-old woman was admitted to our hospital with the sudden onset of dyspnea after eating. The patient had undergone nephrectomy for a left renal tumor 24 years previously. The patient had been prescribed ferrous citrate for iron-deficiency anemia. She complained of appetite loss a few days before admission but had no abdominal pain. CT scan showed no abnormalities in the lungs but a mass in the liver.

Utility of artificial intelligence for detection of pneumothorax on chest radiopgraphs done after transthoracic percutaneous transthoracic biopsy guided by computed tomography.

OBJETIVE: To assess the ability of an artificial intelligence software to detect pneumothorax in chest radiographs done after percutaneous transthoracic biopsy. MATERIAL AND METHODS: We included retrospectively in our study adult patients who underwent CT-guided percutaneous transthoracic biopsies from lung, pleural or mediastinal lesions from June 2019 to June 2020, and who had a follow-up chest radiograph after the procedure. These chest radiographs were read to search the presence of pneumothorax independently by an expert thoracic radiologist and a radiodiagnosis resident, whose unified lecture was defined as the gold standard, and the result of each radiograph after interpretation by the artificial intelligence software was documented for posterior comparison with the gold standard. RESULTS: A total of 284 chest radiographs were included in the study and the incidence of pneumothorax was 14.4%. There were no discrepancies between the two readers' interpretation of any of the postbiopsy chest radiographs. The artificial intelligence software was able to detect 41/41 of the present pneumothorax, implying a sensitivity of 100% and a negative predictive value of 100%, with a specificity of 79.4% and a positive predictive value of 45%. The accuracy was 82.4%, indicating that there is a high probability that an individual will be adequately classified by the software. It has also been documented that the presence of Port-a-cath is the cause of 8 of the 50 of false positives by the software. CONCLUSIONS: The software has detected 100% of cases of pneumothorax in the postbiopsy chest radiographs. A potential use of this software could be as a prioritisation tool, allowing radiologists not to read immediately (or even not to read) chest radiographs classified as non-pathological by the software, with the confidence that there are no pathological cases.

Chest tube removal at different gas flows in prolonged air leak: a randomized non-inferiority trial.

OBJECTIVES: To evaluate the safety and feasibility of removing drainage tubes at larger size of air leak in patients with prolonged air leak after pulmonary surgery. METHODS: Ninety-five patients who underwent pulmonary surgery with prolonged air leak in our centre were enrolled in this randomized controlled, single-centre, non-inferiority study. The drainage tube was clamped with a stable size of air leak observed over the last 6 h, which was quantified by gas flow rate using the digital drainage system. The control group (n = 48) and the study group (n = 46) had their drainage tube clamped at 0-20 ml/min and 60-80 ml/min, respectively. We continuously monitored clinical symptoms, conducted imaging and laboratory examinations, and decided whether to reopen the drainage tube. RESULTS: The reopening rate in the study group was not lower than that in the control group (2.08% vs 6.52%, P > 0.05). The absolute difference in reopening rate was 4.44% (95% confidence interval -0.038 to 0.126), with an upper limit of 12.6% below the non-inferiority margin (15%). There were significant differences in the length of stay [16.5 (13-24.75) vs 13.5 (12-19.25), P = 0.017] and the duration of drainage [12 (9.25-18.50) vs 10 (8-12.25), P = 0.007] between the control and study groups. No notable differences were observed in chest X-ray results 14 days after discharge or in the readmission rate. CONCLUSIONS: For patients with prolonged air leak, removing drainage tubes at larger size of air leak demonstrated similar safety compared to smaller size of air leak, and can shorten both length of stay and drainage duration. CLINICAL TRIAL REGISTRATION NUMBER: Name of registry: Gas flow threshold for safe removal of chest drainage in patients with alveolar-pleural fistula prolonged air leak after pulmonary surgery. Registration number: ChiCTR2200067120. URL: https://www.chictr.org.cn/.

An externally validated guide to anatomical interpretation using a direct-vision ('IRIS') feeding tube.

BACKGROUND & AIMS: Most of the 11.5 million feeding tubes placed annually in Europe and the USA are placed 'blind'. This carries a 1.6% risk that these tubes will enter the lung and 0.5% cause pneumothorax or pneumonia regardless of whether misplacement is identified prior to feeding. Tube placement by direct vision may reduce the risk of respiratory or oesophageal misplacement. This study externally validated whether an 'operator guide' would enable novice operators to differentiate the respiratory and alimentary tracts. METHODS: One IRIS tube was placed in each of 40 patients. Novice operators interpreted anatomical position using the built-in tube camera. Interpretation was checked from recorded images by consultant gastroenterologists and end-of-procedure checks using pH or X-ray checked by Radiologists and a consultant intensivist. RESULTS: The 40 patients were a median of 68y (IQR: 56-75), 70% male, mostly medical (65%), conscious (67.5%) and 70% had no artificial airway. Three tubes were removed due to failed placement. In the remaining 37 placements, novice operators identified the airway in 17 (45.9%) and airway + respiratory tract in 19 (51.4%), but redirected all these tubes into the oesophagus. By using direct vision to reduce the proportion of tubes near the airway or in respiratory tract from 0.514 to 0, operator discrimination between the respiratory and alimentary tracts was highly significant (0.514 vs 0: p < 0.0001, power >99.9% when significance = 0.05). In addition, organ boundaries (respiratory tract vs oesophagus, oesophagus vs stomach, stomach vs intestine) were identified in 100%. CONCLUSIONS: Novice operators, trained using the guide, identified all respiratory misplacements and accurately interpreted IRIS tube position. Guide-based training could enable widespread use of direct vision as a means to prevent tube-related complications.

Refractory Pneumothorax Due to Cystic Pulmonary Metastasis of a Lowgrade Endometrial Stromal Sarcoma: A Case Report.

Low-grade endometrial stromal sarcoma (LG-ESS) is a rare uterine neoplasm. Computed tomography (CT) revealed the presence of multiple small bilateral pulmonary nodules in a 58-year-old woman 1 year after surgery for LG-ESS; the clinical diagnosis was pulmonary metastasis. Hormone therapy with progesterone was initiated, after which most of the solid nodules disappeared and some transformed into cystic lesions. Seven years after hormone therapy, the patient experienced repeated pneumothorax. The cause of the pneumothorax was perforation of a metastatic focus within the wall of a small subpleural cyst that was not evident on CT images.

Occult solitary fibrous tumour of the pleura presenting as recurrent spontaneous pneumothorax.

A woman in her 30s, non-smoker, presented at the emergency department two times because of spontaneous pneumothorax. The first episode was treated with small bore catheter drainage, while during the second episode-occurring only 1 week later-thoracoscopic talcage was attempted. The postoperative course was characterised by slow clinical and radiological resolution, and recurrence 3 days after discharge. Eventually, multiportal video-assisted thoracoscopic exploration identified an interfissural solid mass. Resection and further work-up revealed the diagnosis of 'low-risk' solitary fibrous tumour (SFT) stage pT1N0M0. The interdisciplinary tumour board advised no adjuvant therapy. A CT thorax was scheduled in 1 year for follow-up. The patient was discharged without complications and has had no recurrences of pneumothorax at 6 months of follow-up. This report shows that SFT can easily be missed on initial presentation and should be considered in the differential diagnosis of pneumothorax, especially when frequently recurring.

Intraoperative mechanical ventilation and incidence of pneumothorax in lymphangioleiomyomatosis.

Patients with lymphangioleiomyomatosis (LAM) are considered high risk for most surgeries and require specific anesthetic considerations mainly because of the common spontaneous pneumothorax (PTX). To explore whether intraoperative mechanical ventilation could increase the risk of PTX in those patients, we included 12 surgical patients with LAM in this study, of whom four (33.3%) experienced postoperative PTX. According to our results, patients with higher CT grade, poorer pulmonary function, and a history of preoperative PTX might be more likely to develop postoperative PTX. However, intraoperative mechanical ventilation did not show obvious influence, which might help clinicians reconsider the perioperative management of LAM patients.

Nasogastric tube placement perforating the nasopharynx causing mediastinal passage and feeding into the pleural space.

A mid-60s female with known primary progressive multiple sclerosis was admitted to our hospital with aspiration pneumonia. Due to reduced consciousness, a nasogastric (NG) tube was inserted for feeding. A chest x-ray (CXR) report from a thoracic radiologist confirmed an atypical tip position due to a hiatus hernia but concluded it was almost certainly within the stomach. However, after deteriorating on feed commencement, a CT scan of the chest confirmed the tube had perforated the nasopharynx and run parallel to the oesophagus through the mediastinum into the right pleural space. The patient subsequently developed an empyema and pneumothorax, requiring multiple therapeutic interventions and a prolonged hospital stay. This case demonstrates how the routine insertion of an NG tube can lead to serious complications. Additionally, position check CXRs can be difficult to interpret, so the decision to use the tube must be made cautiously by the clinical team.

Management of Blunt Chest Trauma.

Common mechanisms of blunt thoracic injury include motor vehicle collisions and falls. Chest wall injuries include rib fractures and sternal fractures; treatment involves supportive care, multimodal analgesia, and pulmonary toilet. Pneumothorax, hemothorax, and pulmonary contusions are also common and may be managed expectantly or with tube thoracostomy as indicated. Surgical treatment may be considered in select cases. Less common injury patterns include blunt trauma to the tracheobronchial tree, esophagus, diaphragm, heart, or aorta. Operative intervention is more often required to address these injuries.

Endobronchial silicone spigot in prolonged air leaks: Nationwide study on outcomes and risk factors for treatment failure.

BACKGROUND: The endobronchial silicone spigot, also known as the endobronchial Watanabe spigot, is used in bronchoscopic interventions to manage prolonged pulmonary air leakage. However, the outcomes of this procedure have not been thoroughly investigated. METHODS: Using a Japanese national inpatient database from April 2014 to March 2022, we assessed the clinical characteristics and outcomes of all eligible patients who received the endobronchial spigot. We also investigated risk factors associated with treatment failure. Treatment failure was defined as in-hospital death or the need for surgery after bronchial occlusion. RESULTS: We analyzed data of 1095 patients who underwent bronchial occlusion using the endobronchial spigot. Among them, 252 patients (23.0%) died during hospitalization, and 403 patients (36.8%) experienced treatment failure. Factors associated with treatment failure included age between 85 and 94 years (odds ratio [OR] 1.83; 95% confidence intervals [CI], 1.04-3.21); male sex (OR 2.43; 95% CI, 1.44-4.11); low Barthel index score; comorbidities of interstitial pneumonia (OR 1.71; 95% CI, 1.18-2.48); antibiotics treatment (OR 1.45; 95% CI, 1.02-2.07); steroids treatment (OR 1.59; 95% CI, 1.07-2.36); and surgery prior to bronchial occlusion (OR 2.08; 95% CI, 1.29-3.35). In contrast, pleurodesis after bronchial occlusion (OR 0.49; 95% CI, 0.32-0.75), and admission to high-volume hospitals were inversely associated with treatment failure (OR 0.58; 95% CI, 0.37-0.90). CONCLUSIONS: The endobronchial Watanabe spigot could be a nonsurgical treatment option for patients with prolonged pulmonary air leaks. Our findings will help identify patients who may benefit from such bronchial interventions.

Unmasking a hidden culprit: late-presenting congenital diaphragmatic hernia beyond infancy: A case report and literature review.

BACKGROUND: Congenital diaphragmatic hernia (CDH) is a rare congenital anomaly with abnormal diaphragm development, typically diagnosed prenatally or soon after birth. Late-presenting CDH presents diagnostic challenges due to nonspecific symptoms that can lead to misdiagnoses. METHODS: This report discusses a 35-month-old female initially presenting with predominant gastrointestinal symptoms and minimal respiratory distress. Initial radiographic findings suggested a left tension pneumothorax, prompting further investigation. RESULTS: Subsequent diagnostic efforts revealed a Bochdalek-type left CDH, with several abdominal organs herniated into the thoracic cavity. The case was managed through laparotomy, where herniated contents were successfully repositioned into the abdominal cavity. This intervention underscores the need for high clinical suspicion and the importance of distinguishing between similar presentations, such as tension pneumothorax and tension gastrothorax, which require different management strategies. CONCLUSION: The case illustrates the importance of considering CDH in differential diagnoses for older pediatric patients with atypical symptoms. Early recognition and appropriate management are key to improving patient outcomes.

Macklin Effect: From Pathophysiology to Clinical Implication.

Air leak syndromes (such as pneumomediastinum, pneumothorax, or subcutaneous emphysema) are frequent complications of acute respiratory distress syndrome (ARDS). Unfortunately, the development of air leaks is associated with worse outcomes. In addition, it has been hypothesized that the development of pneumomediastinum could be a marker of disease severity in patients with respiratory failure receiving noninvasive respiratory support or assisted ventilation. The so-called Macklin effect (or pulmonary interstitial emphysema) is the air dissection of the lung bronchovascular tree from peripheral to central airways following injury to distal alveoli. Ultimately, the progression of the Macklin effect leads to the development of pneumomediastinum, subcutaneous emphysema, or pneumothorax. The Macklin effect is identifiable on a chest computed tomography (CT) scan. The Macklin effect could be an accurate predictor of barotrauma in patients with ARDS (sensitivity = 89.2% [95% CI: 74.6-96.9]; specificity = 95.6% [95% CI: 90.6-98.4]), and may be a marker of disease severity. Accordingly, the detection of the Macklin effect on a chest CT scan could be used to select which patients with ARDS might benefit from different treatment algorithms, including advanced respiratory monitoring, early intubation, or, potentially, the institution of early extracorporeal support with or without invasive ventilation. In this video, the authors summarize the pathophysiology and potential clinical significance and applications of the Macklin effect in patients with acute respiratory failure.