Iatrogenic pneumothorax related to mechanical ventilation

Occult tension pneumothorax discovered following imaging for adult trauma patients in the modern major trauma system: a multicentre observational study

BACKGROUND

Tension pneumothorax following trauma is a life-threatening emergency and radiological investigation is normally discouraged prior to treatment in traditional trauma doctrines such as ATLS. Some trauma patients may be physiologically stable enough for diagnostic imaging and occult tension pneumothorax is discovered radiologically. We assessed the outcomes of these patients and compared them with those with clinical diagnosis of tension pneumothorax prior to imaging.

METHODS

A multicentre civilian-military collaborative network of six major trauma centres in the UK collected observational data from adult patients who had a diagnosis of traumatic tension pneumothorax during a 33-month period. Patients were divided into 'radiological' (diagnosis following CT/CXR) or 'clinical' (no prior CT/CXR) groups. The effect of radiological diagnosis on survival was analysed using multivariable logistic regression that included the covariates of age, gender, comorbidities and Injury Severity Score.

RESULTS

There were 133 patients, with a median age of 41 (IQR 24-61); 108 (81%) were male. Survivors included 49 of 59 (83%) in the radiological group and 59 of 74 (80%) in the clinical group (p=0.487). Multivariable logistic regression showed no significant association between radiological diagnosis and survival (OR 2.40, 95% CI 0.80 to 7.95; p=0.130). There was no significant difference in mortality between the groups.

CONCLUSION

Radiological imaging may be appropriate for selected trauma patients at risk of tension pneumothorax if they are considered haemodynamically stable. Trauma patients may be physiologically stable enough for radiological imaging but have occult tension pneumothorax because they did not have the typical clinical presentation. The historical dogma of the 'forbidden scan' no longer applies to such patients.

Mechanical Ventilation during Bronchiolitis: The Macklin Effect

This is a case of barotrauma imaging (Macklin effect) after invasive mechanical ventilation in a 14-week-old newborn with complicated bronchiolitis. Teaching point: Imaging could help us improve defining the anatomical boundaries of the Macklin effect, an incompletely known anatomo-physiological entity.

Improved detection of air-filled lesions using computed tomography in dogs with recurrent spontaneous pneumothorax through reduction of pulmonary atelectasis via positive pressure ventilation

Introduction

Spontaneous pneumothorax in dogs is predominantly caused by the rupture of air-filled lesions, such as bullae or blebs. The efficacy of Computed Tomography (CT) in detecting these lesions has been deemed limited due to its reportedly low sensitivity. This retrospective, cross-sectional study investigates the utility of CT in eight dogs diagnosed with recurrent pneumothorax, all of which had surgical confirmation of the cause of the pneumothorax.

Materials and methods

Thoracic radiographs were obtained before and the day following the CT studies. Initially, a CT study was conducted without positive pressure ventilation (pre-PPV CT). Subsequent CT studies were performed post-evacuation of pneumothorax and with positive pressure ventilation of 15 cmH2O until lung atelectasis was resolved (post-PPV CT). The pre-PPV CT and post-PPV CT images were anonymized and reviewed by two board-certified radiologists. The presence and morphology of air-filled lesions were evaluated on all images. Surgical findings were recorded and compared to the CT findings.

Results

Air-filled lesions were detected in 5 out of 8 dogs in the pre-PPV CT studies and in all 8 dogs in the post-PPV CT studies. The CT findings of air-filled lesions were consistent with surgical findings. None of the dogs showed increased severity of pneumothorax in radiographs taken the day following the CT studies.

Discussions

The study concludes that the resolution of lung atelectasis by evacuation of pneumothorax and positive pressure ventilation during CT studies is feasible and enhances the detection of air-filled lesions in dogs with recurrent spontaneous pneumothorax. This could potentially aid in improving surgical planning.

Unexpected Tension Pneumothorax Developed during Anesthetic Induction Aggravated by Positive Pressure Ventilation: A Case Report

Background and Objectives: Tension pneumothorax is a life-threatening emergency condition that requires immediate diagnosis and intervention. However, due to the non-specific symptoms and the rarity of its occurrence during surgery, anesthesiologists encounter difficulties in promptly diagnosing tension pneumothorax when it arises intraoperatively. Diagnosing tension pneumothorax can become even more challenging in unexpected situations in patients with normal preoperative evaluation for general anesthesia. Materials and Methods, Results: We report the case of a 66-year-old woman who underwent general anesthesia for oblique lateral interbody fusion surgery of her lumbar spine. Though she did not have any respiratory symptoms prior to the induction of anesthesia, auscultation following endotracheal intubation indicated decreased breathing sound in the left hemithorax of the chest. Subsequently, her vital signs showed tachycardia, hypotension, and hypoxemia, and the ventilator indicated a gradual increase in the airway pressure. We verified the proper depth of the endotracheal tube to exclude one-lung ventilation, and, in the meantime, learned that there had been unsuccessful attempts at left subclavian venous catheterization by the surgical department on the previous day. Tension pneumothorax was diagnosed through portable chest radiography in the operating room, and needle thoracostomy and chest tube insertion were performed immediately, which in turn stabilized her vital signs and airway pressure. The surgery was uneventful, and the chest tube was removed one week later after evaluation by the cardiothoracic department. The patient was discharged from hospital on postoperative day 14 without known complications. Conclusions: Anesthesiologists should be aware of the conditions and risk factors that may cause tension pneumothorax and remain vigilant for signs of its development throughout surgery, even for patients who show normal preoperative assessments. An undetected small pneumothorax without any symptoms can progress to tension pneumothorax through positive pressure ventilation during general anesthesia, posing a life-threatening situation. If a tension pneumothorax is highly suspected through clinical assessments, its prompt differentiation and timely diagnosis are crucial, allowing for rapid intervention to stabilize vital signs.

Role of cardiac and lung ultrasound in the COVID-19 era

INTRODUCTION

The primary diagnostic method of Coronavirus disease 2019 is reverse transcription polymerase chain reaction of the nucleic acid of severe acute respiratory syndrome coronavirus 2 in nasopharyngeal swabs. There is growing evidence regarding the 2019 coronavirus disease imaging results on chest X-rays and computed tomography but the accessibility to standard diagnostic methods may be limited during the pandemic.

EVIDENCE ACQUISITION

Databases used for the search were MEDLINE (PubMed), Scopus Search, and Cochrane Library. The research took into consideration studies published in English until March 2022 and was conducted using the following research query: ((((sars cov [MeSH Terms])) OR (COVID-19)) OR (Sars-Cov2)) OR (Coronavirus)) AND (((((2d echocardiography [MeSH Terms]) OR (doppler ultrasound imaging [MeSH Terms]))) OR (echography [MeSH Terms])) OR (LUS)) OR ("LUNG ULTRASOUND")).

EVIDENCE SYNTHESIS

Pulmonary and cardiac ultrasound are cost-effective, widely available, and provide information that can influence management.

CONCLUSIONS

Point-of-care ultrasonography is a method that can provide relevant clinical and therapeutic information in patients with COVID-19 where other diagnostic methods may not be easily accessible.

Use of high-flow oxygen therapy in a cat with cardiogenic pulmonary edema

Case summary

A 7-month-old female spayed domestic shorthair cat was presented for respiratory distress due to cardiogenic pulmonary edema. Despite initial treatment and oxygen delivery in an oxygen tent, the cat still showed signs of severe respiratory effort and oxygen saturation measured via pulse oximetry was below 85%. Because the owners declined mechanical ventilation, the cat was transitioned to high-flow oxygen therapy (HFOT). HFOT allowed significant improvement of the respiration parameters within 15 mins without causing clinical complications. The cat was briefly anaesthetised for the placement of the nasal cannula on initiation of HFOT, and the interface was well tolerated thereafter. The cat was transitioned to an oxygen cage after 16 h, weaned from oxygen 4 h later and was discharged after 3 days of hospitalisation. Long-term follow-up showed no abnormalities, and the leading hypothesis was transient myocardial thickening.

Relevance and novel information

The first use of HFOT in a dyspneic cat is described in this study. HFOT could be a life-saving option for cats with severe hypoxemia or do-not-intubate orders that fail to respond to conventional oxygen therapies.

The Global Burden of Pleural Diseases

Pleural diseases include a spectrum of disorders broadly categorized into pneumothorax and pleural effusion. They often cause pain, breathlessness, cough, and reduced quality of life. The global burden of diseases reflects regional differences in conditions and exposures associated with pleural disease, such as smoking, pneumonia, tuberculosis, asbestos, cancer, and organ failure. Disease burden in high-income countries is overrepresented given the availability of data and disease burden in lower-income countries is likely underestimated. In the United States, in 2016, there were 42,215 treat-and-discharge visits to the emergency room for pleural diseases and an additional 361,270 hospitalizations, resulting in a national cost of $10.1 billion.

Pulmonary recruitment maneuver reduces the intensity of post-laparoscopic shoulder pain: a systematic review and meta-analysis

BACKGROUND

Post-laparoscopic shoulder pain (PLSP) is a common complication following laparoscopic surgeries. This meta-analysis aimed to investigate whether pulmonary recruitment maneuver (PRM) was beneficial to alleviated shoulder pain after laparoscopic procedures.

METHODS

We reviewed existing literature in the electronic database from the date of inception to January 31, 2022. The relevant RCTs were independently selected by two authors, after which data extraction, assessment of the risk of bias, and comparison of results.

RESULTS

This meta-analysis included 14 studies involving 1504 patients, among which 607 patients were offered pulmonary recruitment maneuver (PRM) alone or in combination with intraperitoneal saline instillation (IPSI), while 573 patients were treated with passive abdominal compression. The administration of PRM significantly decreased the post-laparoscopic shoulder pain score at 12 h (MD (95%CI) - 1.12(-1.57, - 0.66), n = 801, P < 0.001, I² = 88%); 24 h (MD (95%CI) - 1.45(-1.74, - 1.16), n = 1180, P < 0.001, I² = 78%) and at 48 h (MD (95%CI) - 0.97(-1.57, - 0.36), n = 780, P < 0.001, I² = 85%). We observed high heterogeneity in the study and analyzed the sensitivity but failed to identify the cause of the heterogeneity, which may have resulted from the different methodologies and clinical factors in the included studies.

CONCLUSION

This systematic review and meta-analysis indicate that PRM can reduce the intensity of PLSP. More studies may be needed to explore the usefulness of PRM in more laparoscopic operations besides gynecological surgeries and determine the optimal pressure of PRM or its appropriate combination with other measures. The results of this meta-analysis should be interpreted with caution owing to the high heterogeneity between the analyzed studies.

Spontaneous pneumothorax and COVID-19: Precipitants to a complex HIV-AIDS diagnosis

A 48-year-old male presented with spontaneous pneumothorax requiring chest tube placement in the setting of COVID-19 infection. CT chest revealed bilateral ground-glass opacities and multiple, large, gas-filled, cavitary lesions in the lungs bilaterally. These imaging findings led to an initial HIV diagnosis with the patient presenting at a CD4+ count of <32 cells/µL. He was found to additionally have infections with Mycobacterium kansasii, cytomegalovirus, Pneumocystis jirovecii, and Candida albicans. After developing worsening hypoxic respiratory failure, he developed additional pneumothoraces bilaterally, requiring repeated chest tube placement. He was treated with antimicrobial therapy for his underlying infections and subsequently started on combined antiretroviral therapy.

Unexpected Tension Pneumothorax after Double-Lumen Endotracheal Intubation in Patients with Pulmonary Edema: A Case Report

Tension pneumothorax is a relatively rare complication after anesthetic induction that requires prompt diagnosis and treatment. Several handling errors related to intubation procedures or equipment and vigorous positive pressure ventilation are potentially important etiologies of tension pneumothorax in patients with underlying lung disease or in mechanically ventilated patients. We describe a case of tension pneumothorax observed after double-lumen tube (DLT) insertion followed by single-lumen tube replacement using an airway exchanger catheter in a mechanically ventilated patient. An 84-year-old female on mechanical ventilation underwent minimally invasive cardiac surgery under general anesthesia. Immediately after left-sided DLT insertion using an airway exchanger catheter, oxygen saturation decreased to 89%, peak airway pressure increased to 35 cm H2O with inadequate tidal volume, and blood pressure gradually dropped to 69/41 mmHg. Breath sounds from the right hemithorax were significantly reduced. Severe collapse of the right lung, a flattened diaphragm, and compressed abdominal organs were identified on chest radiography. Therefore, a tube thoracotomy was performed based on the findings of a tension pneumothorax. Then, oxygen saturation, peak airway pressure with adequate tidal volume, and blood pressure improved, and the distended abdomen normalized. After the pneumothorax resolved, a bronchoscopy was performed. Slight redness was noted in the right bronchus, indicating that the DLT was incorrectly inserted into the right side. In conclusion, the possibility of a tension pneumothorax should be considered during DLT intubation or endotracheal tube replacement with an airway exchange catheter.

Intraoperative spontaneous tension pneumothorax during robotic-assisted coronary artery bypass grafting

Patients undergoing robotic-assisted coronary artery bypass grafting are increasing. Several complications have emerged with the increasing use of minimally invasive procedures. We reported a case of spontaneous tension pneumothorax that developed in the ventilated lung during robotic assisted left internal mammary artery harvesting causing severe hemodynamic instability. A sudden rise of airway pressure occurred, and the patient became hypotensive. Immediately, the surgeon was notified to look at the right pleura. Pneumothorax was identified, the right pleura was opened using robotic arms, and the right lung was decompressed. A small emphysematous bulla was identified and stabled. Proper identification of the procedure-associated complications is essential for timely management. Tension pneumothorax is a potentially fatal complication, especially in patients under positive pressure ventilation.

VATS in complicated COVID-19 patients: case series

Common complications of coronavirus disease 2019 (COVID-19) related ARDS and ventilation are barotrauma-induced pneumothorax, pneumatocele and/or empyema. We analysed indications and results of video-assisted thoracoscopic surgery (VATS) in complicated COVID-19 patients. This is a retrospective single-institution study analysing a case series of patients treated by VATS for secondary spontaneous pneumothorax (SSP), pneumatocele and empyema complicating COVID-19, not responding to drainage in Lodi Maggiore Hospital between February 2020 and May 2021. Out of 2076 patients hospitalized in Lodi Maggiore Hospital with COVID-19, nine Males (0,43%; mean age 58,1–33–81) were treated by VATS for complications of pneumonia (6 SSP and 3 empyema; 1 case complicated by haemothorax). 7 patients (77%) had CPAP before surgery for 21.3 days mean (4–38). Mean Operative time was 80.9 min (38–154). Conversion rate was 0%. 3 (33%) patients were admitted to ICU before VATS. Treatments were: bullectomy in six patients (66%), drainage of the pleural space in all patients, pleural decortication and fluid aspiration in five cases (55%). two patients (22%) needed surgery interruption and bilateral ventilation to restore adequate oxygenation. Mortality was 1/9 (11%) due to respiratory failure for persistent pneumonia. In one patient (11%) redo surgery was performed for bleeding. Mean postop Length of Stay (LOS) was 37.9 days (10–77). Our report shows that VATS can be considered an extreme, but effective treatment for COVID-19 patients with SSP, pneumatocele or empyema, for patients who can tolerate general anaesthesia. Attention must be paid to the aerosol-generation of infected droplets.

High-flow nasal cannula improves hypoxemia in dogs failing conventional oxygen therapy

OBJECTIVE

A prospective clinical trial was performed to evaluate the efficacy and tolerance of high-flow nasal cannula (HFNC) in dogs with hypoxemia.

ANIMALS

20 client-owned dogs failing conventional oxygen therapy (COT).

PROCEDURES

Patients admitted to the ICU for treatment of hypoxemic respiratory failure were enrolled in the study. PaO2, SPO2, respiratory rate (RR), and acute patient physiologic and laboratory evaluation scores were obtained at the time of COT failure and after initiation of HFNC. Complications and patient tolerance while receiving HFNC were also recorded.

RESULTS

Compared to COT, the median PaO2 and SO2 were significantly higher when dogs were receiving HFNC (60.8 vs 135.6 mm Hg and 90.7% vs 99.25%, respectively). Dogs receiving HFNC had a significant reduction in median RR as compared to dogs undergoing COT (52 vs 36 breaths per minute). After the initiation of HFNC, all dogs showed clinical improvement as measured by PaO2, SO2, and RR. Of 20 dogs, 6 ultimately failed HFNC and mechanical ventilation was recommended. Nine dogs undergoing HFNC survived to discharge, and acute patient physiologic and laboratory evaluation scores had a significant positive severity correlation with death. Complications included pneumothorax in 1 dog.

CLINICAL RELEVANCE

COT has limited flow rates due to airway irritation caused by room temperature, nonhumidified oxygen. HFNC uses vapor humidification and heated oxygen, allowing for higher flow rates. In people, HFNC is used as escalation of oxygen therapy when COT fails. Dogs treated with HFNC had significant improvements in PaO2, SO2, and RR as compared to COT. HFNC is well tolerated and effective in treating hypoxemia in dogs.

Risk factors for air leakage during invasive mechanical ventilation in pediatric intensive care units

Purpose

This study aimed to investigate air leakage during invasive mechanical ventilation (IMV) in a pediatric intensive care unit (PICU) and explore potential risk factors.

Methods

We conducted a retrospective cohort study of children who underwent IMV in a single-center PICU in a tertiary referral hospital. Air leakage risk factors and factors associated with an improved outcome were assessed.

Results

A total of 548 children who underwent IMV were enrolled in this study. Air leakage occurred in 7.5% (41/548) of the cases in the PICU. Air leakage increased the duration of IMV and hospitalization time. Multivariate logistic regression analysis showed a higher risk of air leakage during IMV for PICU patients with acute respiratory dyspnea syndrome (ARDS) (OR = 4.38), a higher pediatric critical illness score (PCIS) (OR = 1.08), or a higher peak inspiratory pressure (PIP) (OR = 1.08), whereas the risk was lower for patients with central respiratory failure (OR = 0.14). The logistic model had excellent predictive power for air leakage, with an area under the curve of 0.883 and tenfold cross-validation. Patients aged between 1 and 6 years who were diagnosed with measles or pneumonia and had a low positive end-expiratory pressure (PEEP) or high PaO2/FiO2 ratio were associated with improved outcomes. Patients diagnosed with central respiratory failure or congenital heart diseases were associated with less desirable outcomes.

Conclusions

Patients with ARDS, a higher PCIS at admission or a higher PIP were at higher risk of air leakage.

Incidence and management of pneumothorax, pneumomediastinum, and subcutaneous emphysema in COVID-19

Objective

The coronavirus disease 2019 (COVID-19) pandemic reached New York City in March 2020, leading to a state of emergency that affected many lives. Patients who contracted the disease presented with different phenotypes. Multiple reports have described the findings of computed tomography scans of these patients, several with pneumothoraces, pneumomediastinum, and subcutaneous emphysema. Our aim was to describe the incidence and management of pneumothorax, pneumomediastinum, and subcutaneous emphysema related to COVID-19 found on radiologic imaging.

Methods

A retrospective chart review was conducted of all confirmed COVID-19 patients admitted between early March and mid-May to two hospitals in New York City. Patient demographics, radiological imaging, and clinical courses were documented.

Results

Between early March and mid-May, a total of 1866 patients were diagnosed with COVID-19 in the two hospitals included in the study, of which 386 were intubated. The majority of these patients were men (1090, 58.4%). The distribution of comorbidities included the following: hypertension (1006, 53.9%), diabetes (544, 29.6%), and underlying lung disease (376, 20.6%). Among the 386 intubated patients, 65 developed study-specific complications, for an overall incidence of 16.8%; 36 developed a pneumothorax, 2 developed pneumomediastinum, 1 had subcutaneous emphysema, and 26 had a combination of both. The mean time of invasive ventilation was 14 days (0-46, interquartile range = 6-19, median 11). The average of highest positive end expiratory pressure within 72 h of study complication was 11 (5-24) cmH20. The average of the highest peak inspiratory pressure within 72 h of complication was 35.3 (17-52) cmH2O. In non-Intubated patients, 9/1480 had spontaneous pneumothorax, for an overall incidence of 0.61 %.

Conclusion

Intubated patients with COVID-19 pneumonia are at high risk of pneumothorax, pneumomediastinum, and subcutaneous emphysema. These should be considered in differential diagnosis of shortness of breath or hypoxia in a patient with a new diagnosis of COVID-19 or worsening hemodynamics or respiratory failure in an intensive care unit setting.

An occult iatrogenic pneumothorax as a cosmetic procedure complication

A pneumothorax is the abnormal gas accumulation within the pleural space. We present a case of a patient with an occult iatrogenic pneumothorax who presented with symptomatic anemia that substantially improved after a transfusion, diverting the clinical suspicion. As a result, she developed acute respiratory distress, initially considered secondary to a possible pulmonary embolism vs. fat embolism. After computed tomography confirmed the diagnosis, a chest tube was inserted. This case emphasizes the importance of suspecting pneumothorax secondary to cosmetic procedures and using computed tomography as the first diagnostic tool in complex cases since chest x-rays can miss pneumothorax.

Endobronchial valve use in COVID-19 related pneumothorax and persistent air leak

Pneumothoraces may occur rarely in coronavirus (COVID-19) patients, often resulting from a combination of fibrotic parenchymal changes and prolonged high-pressure ventilation. Very few studies have been published describing the management of pneumothorax in the novel COVID-19 pneumonia patients. Although chest drain insertion represents the first line of treatment, a persistent pneumothorax and air leak requiring intervention could be managed by a thoracoscopic procedure or, as is the case here, by endobronchial valve insertion. Endobronchial valve insertion is a minimally invasive technique that provides a treatment option in patients with severe parenchymal COVID-19 related lung disease. As far as the authors are aware this is the first report of the use of endobronchial valves in a COVID-19 patient.

Emergency Medical Services Responder Manual Ventilation Performance

Introduction: Manual ventilation is a basic skill that every emergency medical services (EMS) responder is expected to perform proficiently. Improper manual ventilation may result in significant morbidity; however, there is no feedback mechanism or method of control for the volume, pressure, or frequency during manual ventilation. In this study, we aimed to quantify the volume and peak pressures of manually delivered breaths using a simulated lung.Methods: One hundred ninety-nine volunteer EMS responders from the EMS World Expo 2019 and EMS Today 2020 participated in this study. Each volunteer manually ventilated a simulated lung using a bag-valve-mask (BVM) for 18 breaths. Descriptive statistics were computed for peak pressures (P_peak) and tidal volumes (V_T)), and a multivariable linear regression was conducted to determine whether there was an independent correlation between P_peak or V_T and seven different variables.Results: Both P_peak and V_T delivered by EMS responders had a high level of variability; 82.9% of clinicians delivered at least one breath exceeding the recommended safety thresholds; and 98.0% delivered at least one breath that was inadequate or excessive. Our results showed no likely clinical significant role of sex, hand size, frequency of use, or years of experience in determining P_peak and V_T. Tidal volumes were significantly higher in males (p < 0.001), those using two-hand manual ventilation (p < 0.001), shorter hand length (p = 0.013), higher confidence (p < 0.001), and more years of experience (p < 0.001). Peak pressures were significantly higher in those using two-hand manual ventilation (p < 0.001), wider hand width (p = 0.004), higher confidence (p < 0.001), less frequent use of the BVM per month (p < 0.001), more experience (p < 0.001).Conclusions: Our study demonstrated large variability of V_T and P_peak within and, to a lesser degree, between clinicians. Of the seven variables that might have affected tidal volume or peak pressures, only the use of two hands versus one hand had a potentially clinically significant effect. Our study identifies a clear need for BVM improvement to ensure every practitioner can deliver breaths at appropriate volumes and safe pressures.

Incidence, clinical characteristics and outcome of barotrauma in critically ill patients with COVID-19: a systematic review and meta-analysis

INTRODUCTION

Barotrauma is rare in patients with acute respiratory distress syndrome undergoing mechanical ventilation. Its incidence seems increased among critically ill COVID-19 patients. We performed a systematic review and meta-analysis to investigate the incidence, risk factors and clinical outcomes of barotrauma among critically ill COVID-19 patients EVIDENCE ACQUISITION: PubMed was searched from March 1st, 2020 to August 31st, 2021; case series and retrospective cohort studies concerning barotrauma in adult critically ill COVID-19 patients, either hospitalized in the Intensive Care Unit (ICU) or invasively ventilated were included. Primary outcome was the incidence of barotrauma in COVID-19 versus non-COVID-19 patients. Secondary outcomes were clinical characteristics, ventilator parameters, mortality and length of stay between patients with and without barotrauma.

EVIDENCE SYNTHESIS

We identified 21 studies (six case series, 15 retrospective cohorts). The overall incidence of barotrauma was 11 [95% CI: 8-14]% in critically ill COVID-19 patients, vs. 2 [1-3]% in non-COVID-19, P<0.001; the incidence in mechanically ventilated patients was 14 [11-17]% vs. 4 [2-5]% non-COVID-19 patients, P<0.001. There were no differences in demographic, clinical, ventilatory parameters between patients who did and did not develop barotrauma, while, on average, protective ventilation criteria were always respected. Among COVID-19 patients, those with barotrauma had a higher mortality (60 [55-66] vs. 48 [42-54]%, P<0.001) and a longer ICU length of stay (20 [14-26] vs. 13 [10,5-16] days, P=0.03).

CONCLUSIONS

Barotrauma is a frequent complication in critically ill COVID-19 patients and is associated with a poor prognosis. Since lung protective ventilation was delivered, the ventilatory management might not be the sole factor in the development of barotrauma.

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.

Complications associated with long-term positive-pressure ventilation in dogs and cats: 67 cases

OBJECTIVES

To determine the complications associated with positive-pressure ventilation (PPV) in dogs and cats.

DESIGN

Retrospective study from October 2009 to September 2013.

SETTING

University Teaching Hospital.

ANIMALS

Fifty-eight dogs and 9 cats.

MEASUREMENTS AND MAIN RESULTS

Medical records were retrospectively reviewed; signalment, complications associated with PPV, duration of PPV, and outcome were recorded. Complications most commonly recorded during PPV included hypothermia 41/67 (61%), hypotension 39/67 (58%), cardiac arrhythmias 33/67 (49%), a positive fluid balance 31/67 (46%), oral lesions 25/67 (37%), and corneal ulcerations 24/67 (36%). A definition of ventilator-associated events (VAE) extrapolated from the Center of Disease Control's criteria was applied to 21 cases that received PPV for at least 4 days in this study. Ventilator-associated conditions occurred in 5 of 21 (24%) of cases with infection-related ventilator-associated conditions and ventilator-associated pneumonia identified in 3 of 21 (14%) cases.

CONCLUSIONS

Complications are common and diverse in dogs and cats receiving long-term PPV and emphasizes the importance of intensive, continuous patient monitoring and appropriate nursing care protocols. Many of the complications identified could be serious without intervention and suggests that appropriate equipment alarms could improve patient safety. Development of veterinary specific surveillance tools such as the VAE criteria would aid future investigations and allow for effective multicenter studies.

Clinical impact of pneumothorax in patients with Pneumocystis jirovecii pneumonia and respiratory failure in an HIV-negative cohort

Background

Pneumocystis jirovecii pneumonia (PCP) with acute respiratory failure can result in development of pneumothorax during treatment. This study aimed to identify the incidence and related factors of pneumothorax in patients with PCP and acute respiratory failure and to analyze their prognosis.

Methods

We retrospectively reviewed the occurrence of pneumothorax, including clinical characteristics and results of other examinations, in 119 non-human immunodeficiency virus patients with PCP and respiratory failure requiring mechanical ventilator treatment in a medical intensive care unit (ICU) at a tertiary-care center between July 2016 and April 2019.

Results

During follow up duration, twenty-two patients (18.5%) developed pneumothorax during ventilator treatment, with 45 (37.8%) eventually requiring a tracheostomy due to weaning failure. Cytomegalovirus co-infection (odds ratio 13.9; p = 0.013) was related with occurrence of pneumothorax in multivariate analysis. And development of pneumothorax was not associated with need for tracheostomy and mortality. Furthermore, analysis of survivor after 28 days in ICU, patients without pneumothorax were significantly more successful in weaning from mechanical ventilator than the patients with pneumothorax (44% vs. 13.3%, p = 0.037). PCP patients without pneumothorax showed successful home discharges compared to those who without pneumothorax (p = 0.010).

Conclusions

The development of pneumothorax increased in PCP patient with cytomegalovirus co-infection, pneumothorax might have difficulty in and prolonged weaning from mechanical ventilators, which clinicians should be aware of when planning treatment for such patients.

Bilateral Spontaneous Pneumothorax in a COVID-19 and HIV-Positive Patient: A Case Report

This case report describes a 60 year-old Black-American male with a past medical history of human immunodeficiency virus (HIV) infection and hyperthyroidism, who suffered a bilateral spontaneous pneumothorax (SP) in the setting of coronavirus disease 2019 (COVID-19) pneumonia. SP is a well-established complication in HIV-positive patients and only recently has been associated with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. While HIV and COVID-19 infections have been independently linked with increased risk of SP development, it is unknown if both infections interact in a synergistic fashion to exacerbate SP risk. According to the Centers for Disease Control and Prevention (CDC), patients living with HIV have a higher risk of developing severe COVID-19 infection and the mechanism remains to be elucidated. To the best of our knowledge, this is the first report of a HIV-positive patient, who in the setting of SARS-CoV-2 infection, developed bilateral apical spontaneous pneumothorax and was later found to have a left lower lobe tension pneumothorax. This case highlights the importance of considering SP on the differential diagnosis when HIV-positive patients suddenly develop respiratory distress in the setting of SARS-CoV-2 infection.

Prehospital paramedic pleural decompression: A systematic review

BACKGROUND

Tension pneumothorax (TPT) is a frequent life-threat following thoracic injury. Time-critical decompression of the pleural cavity improves survival. However, whilst paramedics utilise needle thoracostomy (NT) and/or finger thoracostomy (FT) in the prehospital setting, the superiority of one technique over the other remains unknown.

AIM

To determine and compare procedural success, complications and mortality between NT and FT for treatment of a suspected TPT when performed by paramedics.

METHODS

We searched four databases (Ovid Medline, PubMed, CINAHL and Embase) from their commencement until 25^th August 2020. Studies were included if they analysed patients suffering from a suspected TPT who were treated in the prehospital setting with a NT or FT by paramedics (or local equivalent nonphysicians).

RESULTS

The search yielded 293 articles after duplicates were removed of which 19 were included for final analysis. Seventeen studies were retrospective (8 cohort; 7 case series; 2 case control) and two were prospective cohort studies. Only one study was comparative, and none were randomised controlled trials. Most studies were conducted in the USA (n=13) and the remaining in Australia (n=4), Switzerland (n=1) and Canada (n=1). Mortality ranged from 12.5% to 79% for NT and 64.7% to 92.9% for FT patients. A higher proportion of complications were reported among patients managed with NT (13.7%) compared to FT (4.8%). We extracted three common themes from the papers of what constituted as a successful pleural decompression; vital signs improvement, successful pleural cavity access and absence of TPT at hospital arrival.

CONCLUSION

Evidence surrounding prehospital pleural decompression of a TPT by paramedics is limited. Available literature suggests that both FT and NT are safe for pleural decompression, however both procedures have associated complications. Additional high-quality evidence and comparative studies investigating the outcomes of interest is necessary to determine if and which procedure is superior in the prehospital setting.

Contralateral pneumothorax after central line placement in COVID-19 positive patients

Contralateral pneumothorax after percutaneous central venous catheter placement has not been previously reported. Three patients who required intubation and mechanical ventilation for acute respiratory failure due to COVID-19 were identified with a new pneumothorax on routine post-placement chest roentgenogram on the side opposite the catheter placement.  Retrospective review of charts, radiographs, and laboratory studies.  No causative relationship was identified between the percutaneous placement of the central venous catheters and the subsequent pneumothoraces identified on the contralateral side, other than the presence of active COVID-19 viral pneumonia. The timing of the contralateral pneumothoraces were coincidental the placement of the central venous catheters.  We believe these pneumothoraces were a consequence of the pulmonary pathology of the COVID-19 virus.

Pneumothorax in patients with respiratory failure in ICU

Pneumothorax is not an uncommon occurrence in ICU patients. Barotrauma and iatrogenesis remain the most common causes for pneumothorax in critically ill patients. Patients with underlying lung disease are more prone to develop pneumothorax, especially if they require positive pressure ventilation. A timely diagnosis of pneumothorax is critical as it may evolve into tension physiology. Most occurrences of pneumothoraces are readily diagnosed with a chest X-ray. Tension pneumothorax is a medical emergency, and managed with immediate needle decompression followed by tube thoracostomy. A computed tomography (CT) scan of the chest remains the gold standard for diagnosis; however, getting a CT scan of the chest in a critically ill patient can be challenging. The use of thoracic ultrasound has been emerging and is proven to be superior to chest X-ray in making a diagnosis. The possibility of occult pneumothorax in patients with thoracoabdominal blunt trauma should be kept in mind. Patients with pneumothorax in the ICU should be managed with a tube thoracostomy if they are symptomatic or on mechanical ventilation. The current guidelines recommend a small-bore chest tube as the first line management of pneumothorax. In patients with persistent air leak or whose lungs do not re-expand, a thoracic surgery consultation is recommended. In non-surgical candidates, bronchoscopic interventions or autologous blood patch are other options.

Electrical impedance tomography as a tool for monitoring mechanical ventilation. An introduction to the technique

Electrical impedance tomography (EIT) is a non-invasive, radiation-free method of diagnostics imaging, allowing for a bedside, real-time dynamic assessment of lung function. It stands as an alternative for other imagining methods, such as computed tomography (CT) or ultrasound. Even though the technique is rather novel, it has a wide variety of possible applications. In the era of modern mechanical ventilation, a dynamic assessment of patient's respiratory condition appears to fulfil the idea of personalized treatment. Additionally, an increasing frequency of respiratory failure among intensive care populations raises demand for improved monitoring tools. This review aims to raise awareness and presents possible implications for the use of EIT in the intensive care setting.

Pneumothorax in critically COVID-19 patients with mechanical ventilation

Coronavirus disease 2019 (COVID-19) is a public health emergency caused by SARS-CoV-2. A few studies reported pneumothorax in patients with COVID-19. Pneumothorax is associated with an increased morbidity and mortality. Hence, it should be considered during the treatment and follow-up of patients with COVID-19. Herein, we reported four cases of pneumothorax in critical COVID-19 patients hospitalized in the ICU and treated with a mechanical ventilation. All patients were diagnosed with COVID-19, type 1 respiratory failure, and acute respiratory distress syndrome. All patients developed pneumothorax during mechanical ventilation, although the ventilator settings were set to lung-protective strategy.

Pneumothorax in patients with coronavirus disease 2019 pneumonia with invasive mechanical ventilation

OBJECTIVES

Our goal was to evaluate the prevalence of and risk factors for pneumothorax in patients with invasive mechanical ventilation in the intensive care unit (ICU) diagnosed with coronavirus disease 2019 pneumonia.

METHODS

The prevalence of pneumothorax was retrospectively reviewed in 107 patients diagnosed with coronavirus disease 2019 pneumonia and treated in an ICU in Turkey between 11 March 2020 and 30 April 2020.

RESULTS

The patients were aged 19-92 years; 37 (34.6%) were women. Pneumothorax developed in 8 (7.5%) of the intubated patients. Four (50%) of the patients with pneumothorax and 68 (68.7%) of those without it died. In the univariable logistic regression analysis of the presence of comorbid diseases (P = 0.91), positive end-expiratory pressure (P = 0.18), compliance (P = 0.93), peak pressure (P = 0.41) and the Horowitz index (P = 0.13) did not show statistically significant effects in increasing the risk of pneumothorax.

CONCLUSIONS

There was no significant increase or decrease in the risk of pneumothorax in patients treated with invasive mechanical ventilation after the diagnosis of coronavirus disease 2019-related pneumonia/acute respiratory distress syndrome. However, consideration of the risk of pneumothorax in these individuals may have the potential to improve the prognoses in such settings.

COVID-19 Associated Spontaneous Pneumothorax and Pneumopericardium: A Case Report

Novel coronavirus 2019 (COVID-19) has been one of the largest and most devastating global pandemics of our time. There have been several complications of this disease that have also proven to be debilitating and deadly. While primarily affecting the respiratory system, some cases presented with uncommon complications such as pneumopericardium and spontaneous pneumothorax. We present a case of an elderly female diagnosed with COVID-19 found to have both spontaneous pneumothorax and pneumopericardium. She had a complicated hospital course and ultimately succumbed to her illness. While the pathogenesis of these conditions is not yet fully understood, further studies are needed to help clinicians develop treatment and prevention strategies to improve patient outcomes.

Role of chest radiography in the management of COVID-19 pneumonia: An overview and correlation with pathophysiologic changes

Background:

Chest radiography (CXR) is a widely available baseline radiological modality in evaluating symptomatic patients with suspected or confirmed Covid-19 disease. Serial changes can help in monitoring the patients in conjunction with the clinical status of these patients in a hospital setting.

Purpose:

The purpose of this study was to analyse the patterns of radiological findings on chest radiograph (CXR) for suspected and confirmed COVID-19 patients on initial presentation to the emergency medical services (EMS) on admission and to assess the progression and resolution.

Materials and Methods:

In this study, patients who presented to EMS of a multispeciality hospital as suspected or confirmed Covid-19 on consecutive reverse transcriptase polymerase chain reaction (RT-PCR). CXR was examined for findings of haziness, patterns and distribution of opacities. Progression and regression of findings in serial CXR were studied and evaluated with the clinical and laboratory parameters. High resolution CT (HRCT) chest was performed initially for some patients.

Results:

756 RT-PCR confirmed COVID-19 patients were included in our study who had initial CXR. 510 (67.46%) of our patients with positive initial RT-PCR showed abnormal baseline CXR. The abnormal findings were described as haziness akin to ground glass opacities (GGO) on CT, peripheral opacities, patchy parenchymal opacities and consolidation. Peripheral opacities and lower zone distribution were the commonest pattern of CXR abnormalities with bilateral involvement. The severity of findings on serial CXR and radiographic regression was studied along with follow-up to assess response to treatment. Forty-six patients showed features of acute lung injury (ALI). Complications and new CXR findings were reported for patients who were given ventilator support.

Conclusion:

CXR is a valuable baseline radiological investigation on hospital admission in symptomatic patients with suspected or confirmed Covid-19 presenting to the EMS as it helps to monitor the progress and regression of the disease in conjunction with clinical findings.

COVID-19: looking beyond the peak. Challenges and tips for radiologists in follow-up of a novel patient cohort

As the coronavirus pandemic evolves, the focus of radiology departments has begun to change. The acute phase of imaging a new disease entity whilst rationalising radiology services in the face of lockdown has passed. Radiologists are now becoming familiar with the complications of COVID-19, particularly the lung parenchymal and pulmonary vascular sequelae and are considering the impact follow-up imaging may have on departments already struggling with a backlog of suspended imaging in the face of reduced capacity. This review from the British Society of Thoracic Imaging explores both the thoracic and extra-thoracic complications of COVID-19, recognising the importance of a holistic approach to patient follow-up. The British Thoracic Society guidelines for respiratory follow-up of COVID-19 will be discussed, together with newly developed reporting templates, which aim to provide consistency for clinicians as well as an opportunity for longer-term data collection.

Pleural complications in patients with coronavirus disease 2019 (COVID-19): how to safely apply and follow-up with a chest tube during the pandemic?

OBJECTIVES

Severe acute respiratory syndrome coronavirus 2, a novel coronavirus, affects mainly the pulmonary parenchyma and produces significant morbidity and mortality. During the pandemic, several complications have been shown to be associated with coronavirus disease 2019 (COVID-19). Our goal was to present a series of patients with COVID-19 who underwent chest tube placements due to the development of pleural complications and to make suggestions for the insertion and follow-up management of the chest tube.

METHODS

We retrospectively collected and analysed data on patients with laboratory-confirmed COVID-19 in our hospital between 11 March and 15 May 2020. Patients from this patient group who developed pleural complications requiring chest tube insertion were included in the study.

RESULTS

A total of 542 patients who were suspected of having COVID-19 were hospitalized. The presence of severe acute respiratory syndrome coronavirus 2 was confirmed with laboratory tests in 342 patients between 11 March and 15 May 2020 in our centre. A chest tube was used in 13 (3.8%) of these patients. A high-efficiency particulate air filter mounted double-bottle technique was used to prevent viral transmission.

CONCLUSIONS

In patients with COVID-19, the chest tube can be applied in cases with disease or treatment-related pleural complications. Our case series comprised a small group of patients, which is one of its limitations. Still, our main goal was to present our experience with patients with pleural complications and describe a new drainage technique to prevent viral transmission during chest tube application and follow-up.

The effect of bed-to-nurse ratio on hospital mortality of critically ill children on mechanical ventilation: a nationwide population-based study

BACKGROUND

Despite the high workload of mechanical ventilation, there has been a lack of studies on the association between nurse workforce and mortality in mechanically ventilated patients. We evaluated the association of the bed-to-nurse ratio with mortality in ventilated pediatric patients admitted to an intensive care unit (ICU).

METHODS

We conducted a nationwide retrospective analysis by using the Korean National Health Insurance database, which categorizes the bed-to-nurse ratio into 9 grades according to the number of beds divided by the number of full-time equivalent registered nurses in a unit. Patients of ages between 28 days and 18 years were enrolled. Multiple admissions and transfers from other hospitals were excluded. We evaluated the odds ratios (ORs) of in-hospital mortality using 4 groups (Grade 1: bed-to-nurse < 0.50, Grade 2: < 0.63, Grade 3: < 0.77, Grade 4 or above > 0.77) with adjustment of patient factors, hospital factors, and treatment requirements.

RESULTS

Of the 27,849 patients admitted to ICU, 11,628 (41.8%) were on mechanical ventilation. The overall in-hospital mortality rates in Grade 1, Grade 2, Grade 3, and Grade 4 or above group were 4.5%, 6.8%, 6.9%, and 4.7%, respectively. The adjusted ORs (95% CI) for in-hospital mortality of mechanically ventilated patients in the Grade 2, Grade 3, and Grade 4 or above compared to those in Grade 1 were 2.73 (95% CI 1.51-4.95), 4.02 (95% CI 2.23-7.26), and 7.83 (4.07-15.07), respectively. However, for patients without mechanical ventilation, the adjusted ORs of in-hospital mortality were not statistically significant.

CONCLUSION

In mechanically ventilated patients, the adjusted mortality rate increased significantly, as the bed-to-nurse ratio of the ICU increased. Policies that limit the number of ventilated patients per nurse should be considered. Trial registration retrospectively registered.

COVID-19: making the right diagnosis

The commentary below was written by Dr. Gordon Schiff and Maria Mirica for the PRIDE (Primary Care Research in Diagnostic Errors) project, an initiative of the Betsy Lehman Center for Patient Safety and Brigham and Women's Hospital Center for Patient Safety Research and Practice with support from the Gordon and Betty Moore Foundation. It highlights some of the key issues related to diagnostic accuracy issues for COVID-19 and beyond.

Subcutaneous Emphysema in Patients With COVID-19 Infection: A Report of Three Cases

Subcutaneous emphysema is a rare complication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia that should prompt immediate attention to find its cause. Herein, we describe three patients with SARS-CoV-2 pneumonia who were admitted to the ICU and developed subcutaneous emphysema and one with a concomitant pneumothorax. 

Three patients with diagnosis of SARS-CoV-2 pneumonia admitted to the ICU developed subcutaneous emphysema during the hospital admission. One of them who had concomitant pneumothorax required thoracostomy tube for treatment and the other two were monitored clinically without additional interventions. Two patients died during the first two to three weeks of their hospital course. One patient survived and was discharged after 63 days in the hospital.

Subcutaneous emphysema is considered a non-life-threatening condition and is usually self-limited requiring supportive treatment in mild cases. For such cases, observation is appropriate. Patients with newly discovered SE life-threatening pathology, such as pneumothorax, esophageal rupture, and necrotizing infections, should be investigated depending on the clinical setting.

This is one of the first paper that shows the development of subcutaneous emphysema in patients with SARS-CoV-2 pneumonia. This may represent a rare complication of the infection as well as may be attributable to other factors such as increased cough and mechanical ventilation. There is a need for studies on the clinical characteristics of a disease with still many unknown features and a wide clinical spectrum that is still being defined.

Low-pressure pulmonary recruitment maneuver: equal to or worse than moderate-pressure pulmonary recruitment maneuver in preventing postlaparoscopic shoulder pain? A randomized controlled trial of 72 patients

Introduction

The pulmonary recruitment maneuver (PRM) has emerged as an effective way of reducing post-laparoscopic shoulder pain (PLSP). However, the optimal lower pressure level for a PRM to reduce PLSP has not yet been investigated.

Aim

To compare the efficacy of the low-pressure PRM with moderate-pressure PRM in preventing PLSP.

Material and methods

Seventy-two ASA I-II patients who were scheduled for gynecologic LS for non-malignant conditions were enrolled in this study. Group 1 included patients who received the PRM at a maximum pressure of 30-40 cm H₂O in a semi-Fowler position and group 2 included patients who received the PRM at a maximum pressure of 15 cm H₂O in a semi-Fowler position. The primary outcome of the study was the difference in PLSP between the two groups.

Results

There were no significant differences in PLSP and wound pain VAS scores between patients receiving the PRM at 30 cm H₂O and 15 cm H₂O during postoperative pain monitoring (p < 0.05). The groups were also similar with respect to ambulation time (p = 0.215), length of hospital stay (p = 0.556) and the height of the pneumoperitoneum measured on chest X-ray (p = 0.151).

Conclusions

The low-pressure PRM (15 cm H₂O pressure) provides similar efficacy as the moderate-pressure PRM (30-40 cm H₂O) in terms of PLSP, wound pain, height of pneumoperitoneum, time of ambulation and length of hospital stay. We suggest that lower maximal inspiratory pressure of 15 cm H₂O might be preferred to avoid the potential complications of the PRM with higher pressures.

High-flow nasal cannula oxygen therapy in acute hypoxemic respiratory failure in 22 dogs requiring oxygen support escalation

OBJECTIVE

To determine the effect of high-flow nasal cannula (HFNC) oxygen therapy on cardiorespiratory variables and outcome in dogs with acute hypoxemic respiratory failure.

DESIGN

Prospective, sequential clinical trial.

SETTING

University veterinary teaching hospital.

ANIMALS

Twenty-two client-owned dogs that failed to respond to traditional oxygen support.

INTERVENTIONS

Initiation of HFNC therapy after traditional oxygen supplementation failed to increase Spo₂ > 96% and Pao₂ > 75 mm Hg or improve respiratory rate/effort.

MEASUREMENTS AND MAIN RESULTS

Physiological variables, blood gas analyses, and dyspnea/sedation/tolerance scores were collected prior to HFNC initiation (on traditional oxygen support [time 0 or T0]), and subsequently during HFNC oxygen administration at time 30 minutes, 60 minutes, and 7 ± 1 hours. Relative to T0, use of HFNC resulted in a decreased respiratory rate at 1 hour (P = 0.022) and 7 hours (P = 0.012), a decrease in dyspnea score at all times (P < 0.01), and an increase in Spo₂ at all times (P < 0.01). There was no difference in arterial/venous Pco₂ relative to T0, although Paco₂ was correlated with flow rate. Based on respiratory assessment, 60% of dogs responded to HFNC use by 30 minutes, and 45% ultimately responded to HFNC use and survived. No clinical air-leak syndromes were observed.

CONCLUSIONS

HFNC use improved oxygenation and work of breathing relative to traditional oxygen therapies, without impairing ventilation. HFNC use appears to be a beneficial oxygen support modality to bridge the gap between standard oxygen supplementation and mechanical ventilation.

Management of Persistent Pneumothorax With Thoracoscopy and Bleb Resection in COVID-19 Patients

Several studies have been published describing the clinical and radiographic findings of coronavirus disease 2019-related pneumonia. Therefore, there is currently a lack of pathologic data on its effects in intubated patients. Pneumothorax may occur rarely and results from a combination of fibrotic parenchyma and prolonged high-pressure ventilation. Chest drainage represents first-line treatment. However, in cases of persistent pneumothorax, thoracoscopy and bleb resection may be feasible options to reduce air leak and improve ventilation. This report describes the cases of 2 patients with coronavirus disease 2019 who were successfully treated with thoracoscopy, bleb resection, and pleurectomy for persistent pneumothorax.

Bilateral Foreign Body Bronchus

Foreign body of aerodigestive tract is one of the most common emergency which all the otolaryngologists do come across in the pediatric patients. Among the airway and digestive tract foreign bodies, airway foreign bodies always possess major risk. Only 47% cases will give a probable positive history. Most of the time the airway foreign bodies are radiolucent. Apart from the indirect signs like hyperinflation, collapse or pneumothorax there are no direct evidences regarding the type and number of foreign bodies on radiographs. The chances of having multiple foreign bodies in the same bronchus or in both the bronchi are not remote. Babies presenting with foreign bodies in bilateral bronchus have graver prognosis than the babies with unilateral foreign bodies. Here we want to share our experience in managing 7 cases of bilateral foreign body bronchus.

Tension pneumoperitoneum caused by rupture of intraabdominal soft tissue emphysema in a child supported with high-frequency oscillatory ventilation: a case report

Background

We reported a case with tension pneumoperitoneum while being on high-frequency oscillatory ventilation.

Case presentation

A 12-month-old Thai girl presented with acute respiratory distress syndrome, septic shock, and bacterial pneumonia. Although supported with mechanical ventilation, she still had severe hypoxia. She was then transitioned to high-frequency oscillatory ventilation. During a weaning period on day 7, she developed left tension pneumothorax requiring intercostal drainage and a markedly large amount of pneumoperitoneum. In spite of a bedside abdominocentesis, her abdomen was still tense and her hemodynamics was unstable. Subsequently, to exclude hollow viscus perforation, diaphragmatic injury caused by intercostal drainage, or abdominal compartment syndrome, she was transferred for surgery. There was no intestinal perforation. Postoperatively, she was on oxygen therapy, on chest physical therapy, and kept hemodynamically stable until she had recovered.

Conclusion

A case of tension pneumoperitoneum probably caused by high-frequency oscillatory ventilation was reported. Awareness of this condition should be included in the differential diagnosis.

Incidence of Pneumothorax Experienced After Orthognathic Surgery

The purpose of this study is to evaluate the frequency of pneumothorax following orthognathic surgery and describe its clinical presentation. A retrospective analysis of a hospital database was carried out on consecutive patients with normal presurgical clinical assessment, laboratory findings, and chest X-ray who underwent orthognathic surgery from January 2007 to September 2018 in the Department of Oral and Craniomaxillofacial Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine. Two patients (0.038%), 1 male (age 20 years) and 1 female (age 32 years), complained of respiratory difficulty and chest pain and were clearly diagnosed with postoperative pneumothorax by radiographic chest X-rays from a sample of 5229 consecutive patients during the study period. Intercostal drainage under local anesthesia was performed immediately and the treatment effects for both patients were satisfactory. The present study findings indicate that although orthognathic surgeries can be safely performed in patients with craniofacial anomalies, some unexpected complications such as pneumothorax may occur. Therefore, accurate postoperative follow-up must be done in every patient to monitor possible clinical complications. Patients who experience respiratory difficulty and postoperative chest pain may have pneumothorax, and once it is diagnosed, treatment should be promptly carried out to eliminate further severe sequelae.

Unexpected Tension Pneumothorax-Hemothorax during Induction of General Anaesthesia

Tension pneumothorax during general anaesthesia is a rare but possibly deleterious event, especially where predisposing factors are absent or unknown, making diagnosis even challenging. We describe a case of a healthy middle-aged woman, who was planned to receive general anaesthesia for total thyroidectomy. After intubation, the patient experienced marked hypoxemia (SpO2=75%), hypotension, and tachycardia. Manual positive pressure ventilation seemed to worsen hypoxemia and tachycardia, while apnoeic oxygenation through circle system with valve open slightly improved cardiorespiratory collapse. The effect of positive ventilation, along with the absence of breath sounds in the right hemithorax and cardiorespiratory collapse, established the diagnosis of tension pneumothorax, managed immediately with emergency thoracentesis and placement of a thoracostomy tube. The patient was improved and pneumothorax was confirmed with chest X-ray and CT. The latter also confirmed the presence of bilateral multiple bullae. The operation was postponed and the patient was extubated a few hours later, in good condition. After thorough evaluation for any systemic disease, which was negative, the patient underwent two-stage thoracotomy for bullectomy.

Comparison of high flow nasal cannula oxygen administration to traditional nasal cannula oxygen therapy in healthy dogs

OBJECTIVE

To determine the feasibility, degree of respiratory support, and safety of high flow nasal cannula (HFNC) oxygen therapy in sedated and awake healthy dogs, when compared to traditional nasal cannula (TNC) oxygen administration.

DESIGN

Randomized experimental crossover study.

SETTING

University research facility.

ANIMALS

Eight healthy dogs.

INTERVENTIONS

Variable flow rates (L/kg/min) were assessed, TNC: 0.1, 0.2, and 0.4 and HFNC: 0.4, 1.0, 2.0, and 2.5. HFNC was assessed in sedated and awake dogs.

MEASUREMENTS

Variables measured included: inspiratory/expiratory airway pressures, fraction of inspired oxygen (FiO₂ ), end-tidal oxygen (ETO₂ ), end-tidal carbon dioxide (ETCO₂ ), partial pressure of oxygen (PaO₂ ), partial pressure of carbon dioxide (PaCO₂ ), temperature, heart/respiratory rate, arterial blood pressure, and pulse oximetry. Sedation status, complications, and predefined tolerance and respiratory scores were recorded.

MAIN RESULTS

Using HFNC, continuous positive airway pressure (CPAP) was achieved at 1 and 2 L/kg/min. CPAP was not higher at 2.5 than 2 L/kg/min, with worse tolerance scores. Expiratory airway pressures were increased when sedated (P = 0.006). FiO₂ at 0.4 L/kg/min for both methods was 72%. FiO₂ with TNC 0.1 L/kg/min was 27% and not different from room air. The FiO₂ at all HFNC flow rates ≥1 L/kg/min was 95%. PaO₂ for HFNC 0.4 L/kg/min was lower than at other flow rates (P = 0.005). The only noted complication was aerophagia. PaCO₂ was increased with sedation and use of HFNC when compared to baseline (P = 0.006; P < 0.01).

CONCLUSIONS

Use of HFNC in dogs is feasible and safe, provides predictable oxygen support and provides CPAP, but may cause a mild increase in PaCO₂ . Flow rates of 1-2 L/kg/min are recommended. If using TNC, flow rates above 0.1 L/kg/min may attain higher FiO₂ .

Automated detection of moderate and large pneumothorax on frontal chest X-rays using deep convolutional neural networks: A retrospective study

BACKGROUND

Pneumothorax can precipitate a life-threatening emergency due to lung collapse and respiratory or circulatory distress. Pneumothorax is typically detected on chest X-ray; however, treatment is reliant on timely review of radiographs. Since current imaging volumes may result in long worklists of radiographs awaiting review, an automated method of prioritizing X-rays with pneumothorax may reduce time to treatment. Our objective was to create a large human-annotated dataset of chest X-rays containing pneumothorax and to train deep convolutional networks to screen for potentially emergent moderate or large pneumothorax at the time of image acquisition.

METHODS AND FINDINGS

In all, 13,292 frontal chest X-rays (3,107 with pneumothorax) were visually annotated by radiologists. This dataset was used to train and evaluate multiple network architectures. Images showing large- or moderate-sized pneumothorax were considered positive, and those with trace or no pneumothorax were considered negative. Images showing small pneumothorax were excluded from training. Using an internal validation set (n = 1,993), we selected the 2 top-performing models; these models were then evaluated on a held-out internal test set based on area under the receiver operating characteristic curve (AUC), sensitivity, specificity, and positive predictive value (PPV). The final internal test was performed initially on a subset with small pneumothorax excluded (as in training; n = 1,701), then on the full test set (n = 1,990), with small pneumothorax included as positive. External evaluation was performed using the National Institutes of Health (NIH) ChestX-ray14 set, a public dataset labeled for chest pathology based on text reports. All images labeled with pneumothorax were considered positive, because the NIH set does not classify pneumothorax by size. In internal testing, our "high sensitivity model" produced a sensitivity of 0.84 (95% CI 0.78-0.90), specificity of 0.90 (95% CI 0.89-0.92), and AUC of 0.94 for the test subset with small pneumothorax excluded. Our "high specificity model" showed sensitivity of 0.80 (95% CI 0.72-0.86), specificity of 0.97 (95% CI 0.96-0.98), and AUC of 0.96 for this set. PPVs were 0.45 (95% CI 0.39-0.51) and 0.71 (95% CI 0.63-0.77), respectively. Internal testing on the full set showed expected decreased performance (sensitivity 0.55, specificity 0.90, and AUC 0.82 for high sensitivity model and sensitivity 0.45, specificity 0.97, and AUC 0.86 for high specificity model). External testing using the NIH dataset showed some further performance decline (sensitivity 0.28-0.49, specificity 0.85-0.97, and AUC 0.75 for both). Due to labeling differences between internal and external datasets, these findings represent a preliminary step towards external validation.

CONCLUSIONS

We trained automated classifiers to detect moderate and large pneumothorax in frontal chest X-rays at high levels of performance on held-out test data. These models may provide a high specificity screening solution to detect moderate or large pneumothorax on images collected when human review might be delayed, such as overnight. They are not intended for unsupervised diagnosis of all pneumothoraces, as many small pneumothoraces (and some larger ones) are not detected by the algorithm. Implementation studies are warranted to develop appropriate, effective clinician alerts for the potentially critical finding of pneumothorax, and to assess their impact on reducing time to treatment.