Pulmonary barotrauma in COVID-19: A systematic review and meta-analysis

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.

Pulmonary barotrauma in SCUBA diving-related fatalities: a histological and histomorphometric analysis

Arterial gas embolism following pulmonary barotrauma occurs in 13-24% of cases of diving deaths. The study aimed to evaluate the usefulness of a histomorphometric digital analysis in the detection of air space over-distension due to pulmonary barotrauma. The study was performed on lung parenchyma specimens of 12 divers: six had died due to arterial gas embolism following pulmonary barotrauma (mean age at death of 54 years, range of 41-61 years), and six had drowned in saltwater without a diagnosis of pulmonary barotrauma (mean age at death of 54 years, range of 41-66 years) (positive controls). For negative controls, six cases of non-SCUBA divers (mean age of death of 42 years, range of 23-55 years) who died of intracerebral haemorrhage were evaluated. No significant differences were observed in the characteristics of the air spaces between control groups (positive and negative). However, differences were observed in the area occupied by air spaces and the percentage of air space area when we compared the case group to the controls (p < 0.01); and there was a slight difference in the maximum and minimum diameters of air space (p < 0.05). The mean area occupied by air spaces and the mean percentage of air space were the most useful for discriminating pulmonary barotrauma from other causes of death (100% sensitivity and 91.7% specificity). Based on our study, inclusion of an increased pattern of air spaces as a possible diagnostic criterion for pulmonary barotrauma would be useful in discerning the cause of diving death.

Barotrauma in patients with severe coronavirus disease 2019-retrospective observational study

Background

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. Although it is known that the COVID-19 acute respiratory distress syndrome (ARDS) is associated with higher incidence of pulmonary barotrauma, unique mechanisms causing the aforementioned complication are still to be investigated. The goal of this research was to investigate the incidence of barotrauma among COVID-19 patients treated in the intensive care unit (ICU) and to examine different clinical outcomes among those subjects.

Methods

This retrospective observational cohort study included adult COVID-19 patients admitted to ICU from September 1, 2020, to February 28, 2022. All admitted subjects received invasive respiratory support. Subjects were divided into two groups based on occurrence of pulmonary barotrauma. Data were collected from available electronical medical records.

Results

In the study period, a total of 900 subjects met inclusion criteria. Pulmonary barotrauma occurred in 88 (9.8%) of them. Subcutaneous emphysema developed in 73 (83%), pneumomediastinum in 68 (77.3%) and pneumothorax in 54 (61.4%) subjects. A small group of subjects developed less common complications like pneumoperitoneum (8 subjects, 9.1%) and pneumopericardium (2 subjects, 2.3%). Survival rate was higher in control than in barotrauma group [396 (48.8%) vs. 22 (25.0%), P<0.05]. There was also a significant difference between two groups in PaO2/FiO2 ratio on admission, duration of non-invasive respiratory support before mechanical ventilation, duration of mechanical ventilation and duration of ICU and hospital stay, all in favour of control group.

Conclusions

Development of barotrauma in patients with severe forms of COVID-19 disease and in need of respiratory support is associated with longer ICU and hospital stay as well as lower survival rates at hospital discharge. Further efforts are needed in understanding mechanism in developing barotrauma and finding new prevention and treatment options.

Effects of pulmonary air leak on patients with coronavirus disease 2019 (COVID-19): a systematic review and meta-analysis

BACKGROUND

Coronavirus disease 2019 (COVID-19) has posed increasing challenges to global health systems. We aimed to understand the effects of pulmonary air leak (PAL), including pneumothorax, pneumomediastinum and subcutaneous emphysema, on patients with COVID-19.

METHODS

We searched PubMed, Embase and Web of Science for data and performed a meta-analysis with a random-effects model using Stata 14.0. This meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Thirty-five articles were included in the meta-analysis. The data came from 14 countries and included 3,047 COVID-19 patients with PAL, 11,3679 COVID-19 patients without PAL and 361 non-COVID-19 patients with PAL. We found that the incidence of PAL was much higher in COVID-19 patients than in non-COVID-19 patients (odds ratio (OR) = 6.13, 95% CI: 2.09-18.00). We found that the group of COVID-19 patients with PAL had a longer hospital stay (standardized mean difference (SMD) = 0.79, 95% CI: 0.27-1.30) and intensive care unit (ICU) stay (SMD = 0.51, 95% CI: 0.19-0.83) and comprised more ICU (OR = 15.16, 95% CI: 6.51-35.29) and mechanical ventilation patients (OR = 5.52, 95% CI: 1.69-17.99); furthermore, the mortality rate was also higher (OR = 2.62, 95% CI: 1.80-3.82).

CONCLUSIONS

Patients with lung injuries caused by COVID-19 may develop PAL. COVID-19 patients with PAL require more medical resources, have more serious conditions and have worse clinical outcomes.

PROSPERO REGISTRATION NUMBER

CRD42022365047.

Non-Ventilated Patients with Spontaneous Pneumothorax or Pneumomediastinum Associated with COVID-19: Three-Year Debriefing across Five Pandemic Waves

Spontaneous pneumothorax and pneumomediastinum (SP-SPM) are relatively rare medical conditions that can occur with or independently of COVID-19. We conducted a retrospective analysis of SP-SPM cases presented to the emergency departments (EDs) of two University-affiliated tertiary hospitals from 1 March 2020 to 31 October 2022. A total of 190 patients were identified: 52 were COVID-19 cases, and 138 were non-COVID-19 cases. The primary outcome we were looking for was in-hospital mortality. The secondary outcomes concerned the disease severity assessed by (a) days of hospitalization; (b) required mechanical ventilation (MV); and (c) required intensive care (IC). All were investigated in the context of the five pandemic waves and the patients' age and comorbidities. The pandemic waves had no significant effect on the outcomes of these patients. Logistic regression found age (OR = 1.043; 95%CI 1.002-1.085), COVID-19 (OR = 6.032; 95%CI 1.757-20.712), number of comorbidities (OR = 1.772; 95%CI 1.046-3.001), and ground-glass opacities over 50% (OR = 5.694; 95%CI 1.169-27.746) as significant risk predictors of in-hospital death while controlling for gender, smoking, the pandemic wave, and the extension of SP-SPM. The model proved good prediction performance (Nagelkerke R-square = 0.524) and would hold the same significant predictors for MV and IC.

An observational study on factors associated with ICU mortality in Covid-19 patients and critical review of the literature

The novel pandemic caused by SARS-CoV-2 has been associated with increased burden on healthcare system. Recognizing the variables that independently predict death in COVID-19 is of great importance. The study was carried out prospectively in a single ICU in northern Greece. It was based on the collection of data during clinical practice in 375 adult patients who were tested positive for SARS-CoV-2 between April 2020 and February 2022. All patients were intubated due to acute respiratory insufficiency and received Invasive Mechanical Ventilation. The primary outcome was ICU mortality. Secondary outcomes were 28-day mortality and independent predictors of mortality at 28 days and during ICU hospitalization. For continuous variables with normal distribution, t-test was used for means comparison between two groups and one-way ANOVA for multiple comparisons. When the distribution was not normal, comparisons were performed using the Mann-Whitney test. Comparisons between discrete variables were made using the x² test, whereas the binary logistic regression was employed for the definition of factors affecting survival inside the ICU and after 28 days. Of the total number of patients intubated due to COVID-19 during the study period, 239 (63.7%) were male. Overall, the ICU survival was 49.6%, whereas the 28-day survival reached 46.9%. The survival rates inside the ICU for the four main viral variants were 54.9%, 50.3%, 39.7% and 50% for the Alpha, Beta, Delta and Omicron variants, respectively. Logistic regressions for outcome revealed that the following parameters were independently associated with ICU survival: wave, SOFA @day1, Remdesivir use, AKI, Sepsis, Enteral Insufficiency, Duration of ICU stay and WBC. Similarly, the parameters affecting the 28-days survival were: duration of stay in ICU, SOFA @day1, WBC, Wave, AKI and Enteral Insufficiency. In this observational cohort study of critically ill COVID-19 patients we report an association between mortality and the wave sequence, SOFA score on admission, the use of Remdesivir, presence of AKI, presence of gastrointestinal failure, sepsis and WBC levels. Strengths of this study are the large number of critically ill COVID-19 patients included, and the comparison of the adjusted mortality rates between pandemic waves within a two year-study period.

Pneumoperitoneum in a Patient With COVID-19 and Acute Respiratory Distress Syndrome Without Pneumothorax

We present a case report of pneumoperitoneum, pneumomediastinum, and subcutaneous emphysema in a patient with COVID-19 pneumonia-causing acute respiratory distress syndrome (ARDS) without any pneumothorax occurring. Pneumothorax, pneumomediastinum, and subcutaneous emphysema are known complications of barotrauma due to positive pressure from mechanical ventilation which is necessary for patients suffering from a severe case of COVID-19. In our literature search, we could not find any reported case of pneumoperitoneum without pneumothorax occurring. Our case is an important addition to the literature presenting a rare complication of mechanical ventilation in patients with ARDS.

Pneumomediastinum in COVID-19 disease: Clinical review with emphasis on emergency management

Pneumomediastinum can be primary (spontaneous) or secondary to iatrogenic, traumatic, and non-traumatic causes. The incidence of spontaneous and secondary pneumomediastinum is higher in patients with coronavirus disease 2019 (COVID-19) compared to the general population. So, pneumomediastinum should be considered in the differential diagnosis of any patient with COVID-19 presenting with chest pain and breathlessness. A high level of suspicion is required to diagnose this condition promptly. Unlike in other disease conditions, pneumomediastinum in COVID-19 has a complicated course with higher mortality in intubated patients. No guidelines exist for managing pneumomediastinum patients with COVID-19. Therefore, emergency physicians should be aware of the various treatment modalities besides conservative management for pneumomediastinum and life-saving interventions for tension pneumomediastinum.

Clinical use of Macklin-like radiological sign (Macklin effect): A systematic review

INTRODUCTION

Recent studies suggested that Macklin sign is a predictor of barotrauma in patients with acute respiratory distress syndrome (ARDS). We performed a systematic review to further characterize the clinical role of Macklin.

METHODS

PubMed, Scopus, Cochrane Central Register and Embase were searched for studies reporting data on Macklin. Studies without data on chest CT, pediatric studies, non-human and cadaver studies, case reports and series including <5 patients were excluded. The primary objective was to assess the number of patients with Macklin sign and barotrauma. Secondary objectives were: occurrence of Macklin in different populations, clinical use of Macklin, prognostic impact of Macklin.

RESULTS

Seven studies enrolling 979 patients were included. Macklin was present in 4-22% of COVID-19 patients. It was associated with barotrauma in 124/138 (89.8%) of cases. Macklin sign preceded barotrauma in 65/69 cases (94.2%) 3-8 days in advance. Four studies used Macklin as pathophysiological explanation for barotrauma, two studies as a predictor of barotrauma and one as a decision-making tool. Two studies suggested that Macklin is a strong predictor of barotrauma in ARDS patients and one study used Macklin sign to candidate high-risk ARDS patients to awake extracorporeal membrane oxygenation (ECMO). A possible correlation between Macklin and worse prognosis was suggested in two studies on COVID-19 and blunt chest trauma.

CONCLUSIONS

Increasing evidence suggests that Macklin sign anticipate barotrauma in patients with ARDS and there are initial reports on use of Macklin as a decision-making tool. Further studies investigating the role of Macklin sign in ARDS are justified.

Incidence of Air Leaks in Critically Ill Patients with Acute Hypoxemic Respiratory Failure Due to COVID-19

Subcutaneous emphysema, pneumothorax and pneumomediastinum are well-known complications of invasive ventilation in patients with acute hypoxemic respiratory failure. We determined the incidences of air leaks that were visible on available chest images in a cohort of critically ill patients with acute hypoxemic respiratory failure due to coronavirus disease of 2019 (COVID-19) in a single-center cohort in the Netherlands. A total of 712 chest images from 154 patients were re-evaluated by a multidisciplinary team of independent assessors; there was a median of three (2-5) chest radiographs and a median of one (1-2) chest CT scans per patient. The incidences of subcutaneous emphysema, pneumothoraxes and pneumomediastinum present in 13 patients (8.4%) were 4.5%, 4.5%, and 3.9%. The median first day of the presence of an air leak was 18 (2-21) days after arrival in the ICU and 18 (9-22)days after the start of invasive ventilation. We conclude that the incidence of air leaks was high in this cohort of COVID-19 patients, but it was fairly comparable with what was previously reported in patients with acute hypoxemic respiratory failure in the pre-COVID-19 era.

Pneumothorax in hospitalized COVID-19 patients with severe respiratory failure: Risk factors and outcome

PNX was described as an uncommon complication in COVID-19 patients but clinical risk predictors and the potential role in patient's outcome are still unclear. We assessed prevalence, risk predictors and mortality of PNX in hospitalized COVID- 19 with severe respiratory failure performing a retrospective observational analysis of 184 patients admitted to our COVID-19 Respiratory Unit in Vercelli from October 2020 to March 2021. We compared patients with and without PNX reporting prevalence, clinical and radiological features, comorbidities, and outcomes. Prevalence of PNX was 8.1% and mortality was >86% (13/15) significantly higher than in patients without PNX (56/169) (P < 0.001). PNX was more likely to occur in patients with a history of cognitive decline (HR: 31.18) who received non-invasive ventilation (NIV) (p < 0.0071) and with low P/F ratio (HR: 0.99, p = 0.004). Blood chemistry in the PNX subgroup compared to patients without PNX showed a significant increase in LDH (420 U/L vs 345 U/L, respectively p = 0.003), ferritin (1111 mg/dl vs 660 mg/dl, respectively p = 0.006) and decreased lymphocytes (HR: 4.440, p = 0.004). PNX may be associated with a worse prognosis in terms of mortality in COVID patients. Possible mechanisms may include the hyperinflammatory status associated with critical illness, the use of NIV, the severity of respiratory failure and cognitive impairment. We suggest, in selected patients showing low P/F ratio, cognitive impairment and metabolic cytokine storm, an early treatment of systemic inflammation in association with high-flow oxygen therapy as a safer alternative to NIV in order to avoid fatalities connected with PNX.

Occurrence, Risk Factors, and Outcomes of Pulmonary Barotrauma in Critically Ill COVID-19 Patients: A Retrospective Cohort Study

Objective

Pulmonary barotrauma has been frequently observed in patients with COVID-19 who present with acute hypoxemic respiratory failure. This study evaluated the prevalence, risk factors, and outcomes of barotrauma in patients with COVID-19 requiring ICU admission.

Methods

This retrospective cohort study included patients with confirmed COVID-19 who were admitted to an adult ICU between March and December 2020. We compared patients who had barotrauma with those who did not. A multivariable logistic regression analysis was performed to determine the predictors of barotrauma and hospital mortality.

Results

Of 481 patients in the study cohort, 49 (10.2%, 95% confidence interval: 7.6-13.2%) developed barotrauma on a median of 4 days after ICU admission. Barotrauma manifested as pneumothorax (N = 21), pneumomediastinum (N = 25), and subcutaneous emphysema (N = 25) with frequent overlap. Chronic comorbidities and inflammatory markers were similar in both patient groups. Barotrauma occurred in 4/132 patients (3.0%) who received noninvasive ventilation without intubation, and in 43/280 patients (15.4%) who received invasive mechanical ventilation. Invasive mechanical ventilation was the only risk factor for barotrauma (odds ratio: 14.558, 95% confidence interval: 1.833-115.601). Patients with barotrauma had higher hospital mortality (69.4% versus 37.0%; p < 0.0001) and longer duration of mechanical ventilation and ICU stay. Barotrauma was an independent predictor of hospital mortality (odds ratio: 2.784, 95% confidence interval: 1.310-5.918).

Conclusion

s. Barotrauma was common in critical COVID-19, with invasive mechanical ventilation being the most prominent risk factor. Barotrauma was associated with poorer clinical outcomes and was an independent predictor of hospital mortality.

Pneumothorax/pneumomediastinum and pre-existing lung pathology in ventilated COVID-19 patients: a cohort study

Background

There is an increasing number of reports on developing pneumothorax/pneumomediastinum among severe acute respiratory syndrome coronavirus disease 2019 (SARS-COVID-19) patients. The aim of our study was whether pre-existing diffuse lung pathology increases visceral pleural vulnerability resulting in pneumomediastinum and pneumothorax among mechanically ventilated COVID-19 patients?

Methods

A total of 138 consecutive COVID-19 patients admitted to the Intensive Care Unit of Petz Aladár University Teaching Hospital between 1st March 2020 and 1st February 2021 were included. Sixty/138 (43.48%) patients had one or more computer tomography scans of the chest. Analysis was focused on the image defined lung conditions during artificial ventilation.

Results

Thirteen out of 60 ventilated patients developed pneumothorax or pneumomediastinum proven by computer tomography (9.42%). Three/13 patients suffered from pre-existing lung parenchyma pathology, while 10/13 had only COVID-19 infection-related image abnormality. Forty-three/60 patient had healthy lung pre-COVID. Kruskal-Wallis test, Spearman correlation and Cox regression calculations did not reveal any statistically significant result proving increased vulnerability during pressure support therapy and visceral pleural breakdown in patients with pre-existing lung pathologies.

Conclusions

Pre-existing lung pathology does not increase the risk of onset of pneumothorax or pneumomediastinum in comparation with previously healthy lungs of ventilated COVID-19 patients.

Evaluation of the Prevalence of Barotrauma and Affecting Factors in Patients with COVID-19 during Follow-Up in the Intermediate Care Unit

It is known that pneumothorax (PX) and pneumomediastinum (PM) develop due to COVID-19 disease. The objective of our study was to determine the prevalence of PX/PM due to COVID-19 in the intermediate intensive care unit (IMCU) and to evaluate the factors causing barotrauma and also the clinical outcomes of these patients. A total of 283 non-intubated patients with COVID-19 pneumonia followed up in the IMCU in a 1-year period were included in the study. The patients were classified as group 1 (having barotrauma) and group 2 (without barotrauma). The rate of barotrauma was 8.1% (n = 23, group 1). PX developed on the right hemithorax in 12 (70.6%) patients. Group 1 had statistically significantly higher 28-day mortality rates compared with group 2 (p = 0.014). The eosinophil and d-dimer levels of the patients in group 1 were higher, while C-reactive protein (CRP), fibrinogen, and albumin levels were lower than Group 2 (p < 0.001, p = 0.017, p = 0.001, p < 0.001), and p < 0.001, respectively). The similar rates of NIMV administration in our study groups support that barotrauma is not the only mechanism in the development of PX/PM. The findings of high blood eosinophil count and low blood levels of CRP, albumin, and fibrinogen in the barotrauma group of our study might be a pathfinder for future studies.

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.

Myths and Misconceptions of Airway Pressure Release Ventilation: Getting Past the Noise and on to the Signal

In the pursuit of science, competitive ideas and debate are necessary means to attain knowledge and expose our ignorance. To quote Murray Gell-Mann (1969 Nobel Prize laureate in Physics): “Scientific orthodoxy kills truth”. In mechanical ventilation, the goal is to provide the best approach to support patients with respiratory failure until the underlying disease resolves, while minimizing iatrogenic damage. This compromise characterizes the philosophy behind the concept of “lung protective” ventilation. Unfortunately, inadequacies of the current conceptual model–that focuses exclusively on a nominal value of low tidal volume and promotes shrinking of the “baby lung” - is reflected in the high mortality rate of patients with moderate and severe acute respiratory distress syndrome. These data call for exploration and investigation of competitive models evaluated thoroughly through a scientific process. Airway Pressure Release Ventilation (APRV) is one of the most studied yet controversial modes of mechanical ventilation that shows promise in experimental and clinical data. Over the last 3 decades APRV has evolved from a rescue strategy to a preemptive lung injury prevention approach with potential to stabilize the lung and restore alveolar homogeneity. However, several obstacles have so far impeded the evaluation of APRV’s clinical efficacy in large, randomized trials. For instance, there is no universally accepted standardized method of setting APRV and thus, it is not established whether its effects on clinical outcomes are due to the ventilator mode per se or the method applied. In addition, one distinctive issue that hinders proper scientific evaluation of APRV is the ubiquitous presence of myths and misconceptions repeatedly presented in the literature. In this review we discuss some of these misleading notions and present data to advance scientific discourse around the uses and misuses of APRV in the current literature.

Pulmonary Barotrauma in COVID-19 Patients: Experience From a Secondary Care Hospital in Oman

Background

During the COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), many patients developed pulmonary barotrauma either self-inflicted or ventilator-induced. In pulmonary barotrauma, air leaks into extra-alveolar tissue resulting in pneumomediastinum, subcutaneous emphysema, pneumothorax, and pneumoperitoneum.

Methods

After obtaining institutional approval, we retrospectively reviewed data from March 1, 2021, to September 31, 2021. Being a retrospective study, informed consent was not applicable. Patient data were collected from the Al Shifa patient information portal, which is an electronic medical record system available to all hospitals in the Ministry of Health, Oman. After identifying patients with pulmonary barotrauma, the following details were recorded and entered into an Excel sheet (Microsoft Corporation, Albuquerque, New Mexico) and a database was created, which contained the following: age, sex, smoking history, comorbidities, type, location, mode of barotrauma, mode of ventilation, length of intensive care unit (ICU) stay, interventions performed, and overall outcome (survived/deceased).

Results

A total of 529 patients with COVID-19 pneumonia were admitted from March 2021 to September 2021 to the ICU. Twenty-eight patients developed barotrauma of variable severity and required interventions like the placement of intercostal drains. Out of 28, five patients developed spontaneous barotrauma, 14 patients had barotrauma after initiation of non-invasive ventilation, and nine patients had barotrauma as a result of invasive ventilation. The median number of days in the ICU was 19.5 (interquartile range: 12.5-26.5). Of the 28 patients, eight patients survived and were discharged from the hospital.

Conclusion

In this single-center, retrospective study at a secondary care hospital in Oman, we described our experience with patients who suffered pulmonary barotrauma during their ICU admission. We have also presented the incidence of spontaneous versus ventilator-induced barotrauma, the length of stay of these patients, the outcomes in terms of survival or death, the need for tracheostomy, secondary infections, and interventions performed as indicated.

Macklin effect on baseline chest CT scan accurately predicts barotrauma in COVID-19 patients

Purpose

To validate the role of Macklin effect on chest CT imaging in predicting subsequent occurrence of pneumomediastinum/pneumothorax (PMD/PNX) in COVID-19 patients.

Materials and methods

This is an observational, case-control study. Consecutive COVID-19 patients who underwent chest CT scan at hospital admission during the study time period (October 1st, 2020–April 31st, 2021) were identified. Macklin effect accuracy for prediction of spontaneous barotrauma was measured in terms of sensitivity, specificity, positive (PPV) and negative predictive values (NPV).

Results

Overall, 981 COVID-19 patients underwent chest CT scan at hospital arrival during the study time period; 698 patients had radiological signs of interstitial pneumonia and were considered for further evaluation. Among these, Macklin effect was found in 33 (4.7%), including all 32 patients who suffered from barotrauma lately during hospital stay (true positive rate: 96.9%); only 1/33 with Macklin effect did not develop barotrauma (false positive rate: 3.1%). No barotrauma event was recorded in patients without Macklin effect on baseline chest CT scan. Macklin effect yielded a sensitivity of 100% (95% CI: 89.1–100), a specificity of 99.85% (95% CI: 99.2–100), a PPV of 96.7% (95% CI: 80.8–99.5), a NPV of 100% and an accuracy of 99.8% (95% CI: 99.2–100) in predicting PMD/PNX, with a mean advance of 3.2 ± 2.5 days. Moreover, all Macklin-positive patients developed ARDS requiring ICU admission and, in 90.1% of cases, invasive mechanical ventilation.

Conclusions

Macklin effect has high accuracy in predicting PMD/PNX in COVID-19 patients; it is also an excellent predictor of disease severity.

An Imaging Overview of COVID-19 ARDS in ICU Patients and Its Complications: A Pictorial Review

A significant proportion of patients with COVID-19 pneumonia could develop acute respiratory distress syndrome (ARDS), thus requiring mechanical ventilation, and resulting in a high rate of intensive care unit (ICU) admission. Several complications can arise during an ICU stay, from both COVID-19 infection and the respiratory supporting system, including barotraumas (pneumothorax and pneumomediastinum), superimposed pneumonia, coagulation disorders (pulmonary embolism, venous thromboembolism, hemorrhages and acute ischemic stroke), abdominal involvement (acute mesenteric ischemia, pancreatitis and acute kidney injury) and sarcopenia. Imaging plays a pivotal role in the detection and monitoring of ICU complications and is expanding even to prognosis prediction. The present pictorial review describes the clinicopathological and radiological findings of COVID-19 ARDS in ICU patients and discusses the imaging features of complications related to invasive ventilation support, as well as those of COVID-19 itself in this particularly fragile population. Radiologists need to be familiar with COVID-19's possible extra-pulmonary complications and, through reliable and constant monitoring, guide therapeutic decisions. Moreover, as more research is pursued and the pathophysiology of COVID-19 is increasingly understood, the role of imaging must evolve accordingly, expanding from the diagnosis and subsequent management of patients to prognosis prediction.

The Collateral Damage of the Pandemic on Non-COVID Related Pneumothorax Patients: A Retrospective Cohort Study

Background: Since the onset of the COVID-19 pandemic, there have been many reported cases showing the consequences—or the collateral damages—of COVID-19 on patients with non-COVID-related diseases. This study aimed to compare the clinical manifestations and treatment results of non-COVID-related pneumothorax patients before and during the pandemic. Methods: We retrospectively reviewed non-COVID-related pneumothorax patients who visited our hospital before the onset of the pandemic and during the pandemic. The primary outcome was the difference in the amount of pneumothorax between the two periods, and the secondary outcome was the difference in the treatment results between them. Multivariable logistic regression was conducted to find risk factors related to massive pneumothorax. Results: There were 122 and 88 patients in the pre-pandemic and pandemic groups, respectively. There was no significant difference between the two groups with respect to the preoperative demographic variables. However, the median amount of pneumothorax was significantly higher in the pandemic group (pre-pandemic: 34.75% [interquartile range (IQR) 18.30–62.95] vs. pandemic: 53.55% [IQR 33.58–88.80], p < 0.0001) and massive pneumothorax were more frequent in the pandemic group (52.3% vs. 30.3%, p = 0.002). Furthermore, more patients experienced re-expansion pulmonary edema after treatments during the pandemic (p = 0.0366). In multivariable analysis, the pandemic (OR: 2.70 [95% CI 1.49–4.90], p = 0.0011) was related to the occurrence of massive pneumothorax. Conclusion: During the pandemic, patients presented with a larger size of pneumothorax and had more re-expansion pulmonary edema, even in a country that handled the COVID-19 pandemic relatively well.