Barotrauma and pneumothorax

Papilledema Secondary to Barotrauma in a Young Adult With Severe Status Asthmaticus With Ventilatory Failure, Pneumothorax, and a Complex Clinical Course

Intubation and mechanical ventilation are common therapeutic interventions in intensive care unit settings. Barotrauma is a known complication of using positive pressures in a tissue defined by extra alveolar air in locations where it is not generally found in patients receiving mechanical ventilation. Several clinical manifestations of barotrauma include pneumothorax, subcutaneous emphysema, pneumoperitoneum, pneumomediastinum or pneumopericardium, air embolization, and hyperinflated left lower lobe. However, papilledema is an unreported and uncommon complication we observed in one of our patients, making it a unique presentation. We present the case of a young male patient intubated for asthma exacerbation requiring mechanical ventilation with subsequent development of papilledema. Our case report highlights the importance of knowing this rare complication of barotrauma as early commencement of lung-protective strategies will help prevent it.

Case Report: Catastrophic Effects of Using Cannabis Via Bucket Bong in Top End Northern Territory of Australia

The prevalence of cannabis usage is increasing worldwide, including among both Indigenous and non-Indigenous Australians. The long-term effects of cannabis use on the lungs are well-known. However, the acute adverse effects on the lungs are sparsely reported. There are different ways in which cannabis can be inhaled, such as smoking or through a water vaporizing method known as a "bong." An improvised innovative bong device that is commonly used in Northern Australia, called a "bucket bong," uses water and air pressure to assist in cannabis inhalation. In this report, we describe three patients from remote and rural Northern Australian communities presenting with near-life-threatening events (acute pneumonitis and massive pneumothorax) immediately after the use of cannabis via bucket bong.

Pulmonary Barotrauma After Diving Without Breathing Equipment

A case of a 19-year-old male with mediastinal and subcutaneous emphysema consistent with pulmonary barotrauma after diving is reported. He presented with facial swelling, voice change, chest pain, and shortness of breath after multiple dives between 8 and 12 feet deep without underwater breathing equipment in a river. Relevant radiology, including radiographs and computed tomography (CT imaging), and a discussion of pulmonary barotrauma are presented.

Incorporating electrical impedance tomography to transpulmonary pressure-guided PEEP in severe ARDS with pneumothorax and multiple cavitations: a case report

Pneumothorax is a potentially fatal complication in patients with acute respiratory distress syndrome (ARDS), presenting challenges in determining the optimal positive end-expiratory pressure (PEEP) level to prevent atelectasis without exacerbating the pneumothorax. This case report describes the successful application of transpulmonary pressure and electrical impedance tomography (EIT) at the bedside to guide PEEP selection in a patient with ARDS complicated by pneumothorax due to methicillin-resistant Staphylococcus aureus infection. By using minimal PEEP to maintain positive end-expiratory transpulmonary pressure and visualizing lung reopening with EIT, the optimal PEEP level was reaffirmed, even if traditionally considered high. The patient's condition improved, and successful weaning from the ventilator was achieved, leading to a transfer out of the intensive care unit. Clinical trial registration: https://clinicaltrials.gov/show/NCT04081142, identifier NCT04081142.

Recommendations on scuba diving in Birt-Hogg-Dubé syndrome

INTRODUCTION

Although very uncommon, severe injury and death can occur during scuba diving. One of the main causes of scuba diving fatalities is pulmonary barotrauma due to significant changes in ambient pressure. Pathology of the lung parenchyma, such as cystic lesions, might increase the risk of pulmonary barotrauma.

AREAS COVERED

Birt-Hogg-Dubé syndrome (BHD), caused by pathogenic variants in the FLCN gene, is characterized by skin fibrofolliculomas, an increased risk of renal cell carcinoma, multiple lung cysts and spontaneous pneumothorax. Given the pulmonary involvement, in some countries patients with BHD are generally recommended to avoid scuba diving, although evidence-based guidelines are lacking. We aim to provide recommendations on scuba diving for patients with BHD, based on a survey of literature on pulmonary cysts and pulmonary barotrauma in scuba diving.

EXPERT OPINION

In our opinion, although the absolute risks are likely to be low, caution is warranted. Given the relative paucity of literature and the potential fatal outcome, patients with BHD with a strong desire for scuba diving should be informed of the potential risks in a personal assessment. If available a diving physician should be consulted, and a low radiation dose chest computed tomography (CT)-scan to assess pulmonary lesions could be considered.

An implantable soft robotic ventilator augments inspiration in a pig model of respiratory insufficiency

Severe diaphragm dysfunction can lead to respiratory failure and to the need for permanent mechanical ventilation. Yet permanent tethering to a mechanical ventilator through the mouth or via tracheostomy can hinder a patient's speech, swallowing ability and mobility. Here we show, in a porcine model of varied respiratory insufficiency, that a contractile soft robotic actuator implanted above the diaphragm augments its motion during inspiration. Synchronized actuation of the diaphragm-assist implant with the native respiratory effort increased tidal volumes and maintained ventilation flow rates within the normal range. Robotic implants that intervene at the diaphragm rather than at the upper airway and that augment physiological metrics of ventilation may restore respiratory performance without sacrificing quality of life.

Review of risk factors, clinical manifestations, rapid diagnosis, and emergency treatment of neonatal perioperative pneumothorax

Perioperative neonatal pneumothorax (NP) is rare but very fatal. Most of the surgeries and treatments in the neonatal period are time-limited or emergent, and there are often some risk factors for pneumothorax before surgery. Physicians, surgeons and anesthesiologists need to identify possible risk factors for pneumothorax before surgery in preterm babies, patients receiving mechanical ventilation and those with underlying lung disease. The clinical presentation of NP is nonspecific, and patients may rapidly develop life-threatening complications if not promptly diagnosed and managed. This review highlights recent progress in the identification of risk factors, clinical manifestations, diagnosis and management of NP during the perioperative period.

Decompression Illness in a Scuba Diver With Significant Esophageal Injury

Scuba divers are at risk of decompression illness, of which arterial gas embolism is the most feared consequence. Severe complications involving the gastrointestinal tract are rare. In this report, we describe a case of an experienced scuba diver who was forced to rapidly ascend because of a mechanical failure. His course was complicated by severe esophageal mucosal injury including multiple ulcerations. Although he improved clinically, an esophageal stricture subsequently formed, which required dilation. This seems to be the first case report of significant esophageal injury resulting from decompression illness in a scuba diver.

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.

“The role of a negative pressure ventilator coupled with oxygen helmet against COVID-19: a review”

Background

The coronavirus (SARS-COV-2) pandemic has provoked the global healthcare industry by potentially affecting more than 20 14 million people across the globe, causing lasting damage to the lungs, notably pneumonia, ARDS (acute respiratory distress 15 syndrome), and sepsis with the rapid spread of infection. To aid the functioning of the lungs and to maintain the blood oxygen 16 saturation (SpO₂) in coronavirus patients, ventilator assistance is required.

Materials and methods

The main purpose of this article is to outline the need 17 for the introduction of a non-invasive negative pressure ventilator (NINPV) as a promising alternative to positive pressure 18 ventilator (PPV) by elucidating the cons of non-invasive ventilators in clinical conditions like ARDS. Another motive is to 19 profoundly diminish the rate of infection spread by the employment of oxygen helmets, instead of endotracheal intubation in 20 invasive positive pressure ventilator (IPPV) or non-invasive positive pressure ventilator (NIPPV) like face masks and high-flow 21 nasal cannula (HFNC).

Result and conclusion

The integration of oxygen helmet with NPV would result in a number of notable facets including the 22 degree of comfort delivered to patients who are exposed to various ventilator-induced lung injuries (VILI) in the forms of 23 atelectasis, barotrauma, etc. Likewise, preventing the aerosol-generating procedures (AGP) diminishes the rate of nosocomial 24 infections and providing a better environment to both the patients and the healthcare professionals.

Suspected Primary Spontaneous Asymptomatic Pneumothorax in a Cat

Spontaneous pneumothorax (SPT) is a documented emergency of the respiratory tract condition classified as either primary or secondary based on the presence of underlying pulmonary conditions. All reported SPT in the feline literature are evaluated for respiratory clinical signs. Primary SPT without underlying pathology or without clinical signs is not reported in cats. This case report describes a 10-year-old domestic longhair cat that was referred for evaluation of chronic lethargy with severe azotemia and placement of a subcutaneous ureteral bypass (SUB) system. Prior to presentation, the cat was diagnosed with renal insufficiency and treated medically with no resolution. Clinical examination under sedation revealed right-sided renomegaly. Thoracic radiographs revealed gas in the caudodorsal pleural space and concurrent pulmonary atelectasis. No respiratory clinical signs were present. Thoracic CT showed two pulmonary bullae, one located in the right caudal lung lobe and one in the cranial segment of the left cranial lung lobe. Abdominal ultrasound showed a right-sided ureteral obstruction. Medical management was elected for the spontaneous pneumothorax. A SUB was placed to address the ureteral obstruction; no complications were noted during recovery. The cat was free of clinical signs of respiratory disease after a follow-up time of nine months. This is the first reported case of a cat diagnosed with a nonclinical suspected primary spontaneous pneumothorax with no concurrent predisposing pulmonary pathology.

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

BACKGROUND

An ever-increasing number of studies have reported an increased incidence of spontaneous pulmonary barotrauma such as pneumothorax, pneumomediastinum, and subcutaneous emphysema in patients with COVID-19. We conducted this systematic review and meta-analysis to assess the value and significance of the available data.

METHODS

A thorough systematic search was conducted to identify studies of barotrauma in hospitalized patients with COVID-19. Data analysis of case reports was done using a statistical package for the social sciences (SPSS) version 22, and meta-analysis was performed using CMA-3.

RESULTS

We identified a total of 4488 studies after thorough database searching.118 case reports and series, and 15 observational studies were included in the qualitative analysis. Fifteen studies were included in the quantitative analysis. The observational studies reported barotrauma in 4.2% (2.4-7.3%) among hospitalized patients; 15.6% (11-21.8%) among critically ill patients; and 18.4% (13-25.3%) in patients receiving invasive mechanical ventilation, showing a linear relationship of barotrauma with the severity of the disease. In addition, barotrauma was associated with a longer length of hospital stay, more extended ICU stay, and higher in-hospital mortality. Also, a slightly higher odds of barotrauma was seen in COVID-19 ARDS compared with non-COVID-19 ARDS.

CONCLUSION

COVID-19 pneumonia is associated with a higher incidence of barotrauma. It presents unique challenges for invasive and non-invasive ventilation management. Further studies are required to unravel the underlying pathophysiology and develop safer management strategies.

Pulmonary alveolar proteinosis with an unusual bronchoscopic complication

Pulmonary alveolar proteinosis (PAP) is a rare respiratory syndrome, which can be challenging to diagnose given its non-specific presentation and imaging findings. While most primary cases of PAP have an autoimmune basis, the triggers for the disease are uncertain with occupational factors increasingly thought to be important. We report the unusual complication of pneumomediastinum and bilateral pneumothoraces following endobronchial ultrasound-guided transbronchial needle aspirate in the setting of PAP. We discuss the possible physiological mechanisms of this complication, which appears to be more common in conditions with reduced lung compliance.

Is continuous positive airway pressure therapy in COVID-19 associated with an increased rate of pulmonary barotrauma?

Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) has infected over 150 million people worldwide, with over 3 million deaths as of 6 May 2021 [1]. In the UK, approximately 15% of individuals affected by coronavirus disease 2019 (COVID-19) have required admission to hospital [2] and those with severe disease require advanced respiratory support including invasive mechanical ventilation (IMV) [3]. Due to the considerable scale of the pandemic, noninvasive continuous positive airway pressure (CPAP) has been utilised for COVID-19-related type I respiratory failure as a therapeutic strategy to improve patient outcomes [4, 5] and also to preserve IMV capacity during a challenging time for acute healthcare providers. However, its exact role is unclear and is the subject of a UK multicentre trial [6].

An increased incidence of pulmonary barotrauma in patients receiving CPAP for #COVID19 pneumonia was observed during the second peak of infections at this centre in the UKhttps://bit.ly/3qeSTp9

Outcomes of Barotrauma in Critically Ill COVID-19 Patients With Severe Pneumonia

Background:

Pneumomediastinum and pneumothorax are complications which may be associated with barotrauma in mechanically ventilated patients. The current literature demonstrates unclear outcomes regarding barotrauma in critically ill patients with severe COVID-19. The purpose of this study was to examine the incidence of barotrauma in patients with severe COVID-19 pneumonia and its influence on survival.

Study Design and Methods:

A retrospective cohort study was performed from March 18, 2020 to May 5, 2020, with follow-up through June 18, 2020, encompassing critically ill intubated patients admitted for COVID-19 pneumonia at an academic tertiary care hospital in Brooklyn, New York. Critically ill patients with pneumomediastinum, pneumothorax, or both (n = 75) were compared to those without evidence of barotrauma (n = 206). Clinical characteristics and short-term patient outcomes were analyzed.

Results:

Barotrauma occurred in 75/281 (26.7%) of included patients. On multivariable analysis, factors associated with increased 30-day mortality were elevated age (HR 1.015 [95% CI 1.004-1.027], P = 0.006), barotrauma (1.417 [1.040-1.931], P = 0.027), and renal dysfunction (1.602 [1.055-2.432], P = 0.027). Protective factors were administration of remdesivir (0.479 [0.321-0.714], P < 0.001) and receipt of steroids (0.488 [0.370-0.643], P < 0.001).

Conclusion:

Barotrauma occurred at high rates in intubated critically ill patients with COVID-19 pneumonia and was found to be an independent risk factor for 30-day mortality.

Case Report: Barotrauma in COVID-19 Case Series

Severe acute respiratory syndrome coronavirus 2 can cause pulmonary complications, such as increased risk of barotrauma (BT), but its prevalence and risk factors are not known. In this case series, the course of BT and its related risk factors were discussed in patients with COVID-19 who were admitted to the intensive care unit. Medical records of the patients with COVID-19 and BT and hospitalized in the intensive care unit for 5 months were extracted. The course of BT and its possible associated risk factors are descriptively presented. Among 103 patients with COVID-19 who were intubated, 13 patients (12.6%) had BT. One patient developed BT before intubation. All patients with BT were male. Half of them developed BT in the first 5 days of intubation. Eight patients (61.53%) had a positive culture for Klebsiella pneumoniae. Nine patients (69.9%) died. High positive end-expiratory pressure, coinfection with bacterial pneumonia, and history of lung disease may affect BT incidence. The treatment team should increase their upervision on the ventilator setting, especially in the first week of intubation.

Acute Kidney Injury and Advanced Kidney Disease in the COVID-19 Pandemic: Proceedings From a National Kidney Foundation Symposium

The coronavirus disease 2019 (COVID-19) pandemic is an unprecedented and historic public health crisis that continues to expand and evolve. The National Kidney Foundation held a 2-part continuing medical education live virtual symposium on July 16 and July 24, 2020, to address the multiple challenges of COVID-19 in the context of advanced chronic kidney disease. Faculty addressed the pathophysiology, impact, risks, and management of COVID-19 as it relates to advanced kidney disease. Testing, risk mitigation, and inpatient and outpatient management were also addressed. This concise review addresses major findings of the symposium along with certain updates regarding vaccinations since then. These findings include: (1) severe COVID-19 infection has been associated with acute kidney injury, (2) it is essential to prevent and actively manage acute kidney injury to decrease mortality in these critically ill patients, (3) management of patients with advanced kidney disease should be geared toward minimizing their risk for exposure while making sure they are receiving adequate treatments, and (4) patients with kidney disease, especially ones in advanced stages, should be prioritized for vaccination.

Immediate pneumothorax after neurosurgical procedures

Objective

Pneumothorax after neurosurgical procedures is very rare and incompletely understood. This study was performed to explore the clinical characteristics and pathogenesis of pneumothorax after neurosurgery.

Methods

We retrospectively evaluated patients admitted from December 2016 to April 2019 for treatment of spontaneous intracranial hemorrhage. The inclusion criteria were neurosurgical procedures (open surgeries or endovascular intervention) performed under general anesthesia, no performance of central venous puncture during surgery, and occurrence of pneumothorax immediately after the neurosurgical procedure.

Results

Eight patients developed pneumothorax after neurosurgical procedures for spontaneous intracranial hemorrhage under general anesthesia. Of the eight patients, seven had aneurysmal subarachnoid hemorrhage and one had left temporal–parietal hemorrhage. The lung injury prediction score (LIPS) was 3, 4, 5, 6, and 9.5 in three, one, two, one, and one patient, respectively. During the operation, volume-controlled ventilation (tidal volume, 8–10 mL/kg) was selected for all patients.

Conclusions

Neurogenic pulmonary edema, inappropriate mechanical ventilation, and stimulation by endotracheal intubation might conjointly contribute to postoperative pneumothorax. To avoid this rare entity, mechanical ventilation with a low tidal volume or low pressure during general anesthesia should be adopted for patients with hemorrhagic cerebrovascular diseases involving the temporal lobe and a LIPS of >3.

Barotrauma Linked to Coronavirus Disease 2019 Infection in Younger Patients: A Case Series

Patients infected with coronavirus disease 2019 (COVID-19) on invasive mechanical ventilation were found to have high rates of barotrauma. Herein, we present five patients admitted to the intensive care unit between March and April 2020, who developed barotrauma as a complication of COVID-19 pneumonia. This series includes four males and one female with a mean age of 54 years, most without significant chronic comorbidities or former tobacco use. All were intubated for hypoxic respiratory failure due to the COVID-19 infection. The diagnosis of barotrauma was confirmed via radiography showing the presence of pneumothorax, pneumomediastinum, or subcutaneous emphysema on radiographic imaging. At the time, they were evaluated for convalescent plasma infusion, remdesivir, and interleukin-6 inhibitor. Each of the five patient's hospital courses were documented. The average number of days between intubation and subsequent barotrauma was 6.8 days with the mean length of hospital stay being 49 days. Three of the five patients passed away due to complications related to COVID-19. Due to the unknown nature of the virus, our findings add to the growing evidence that those infected, even without significant comorbidities, are at high risk for pulmonary complications and in-hospital mortality.

A new mode of mechanical ventilation: positive + negative synchronized ventilation

Supporting patients suffering from severe respiratory diseases with mechanical ventilation, obstacles are often encountered due to pulmonary and/or thoracic alterations, reductions in the ventilable lung parenchyma, increases in airway resistance, alterations in thoraco-pulmonary compliance, advanced age of the subjects. All this involves difficulties in finding the right ventilation parameters and an adequate driving pressure to guarantee sufficient ventilation. Therefrom, new mechanical ventilation techniques were sought that could help overcome the aforementioned obstacles. A new mode of mechanical ventilation is being presented, i.e., a Positive + Negative Synchronized Ventilation (PNSV), characterized by the association and integration of two pulmonary ventilators; one acting inside the chest with positive pressures and one externally with negative pressure. The peculiarity of this combination is the complete synchronization, which takes place with specific electronic modifications. The PNSV can be applied both in a completely non-invasive and invasive way and, therefore, be used both in acute care wards and in ICU. The most relevant effect found, due to the compensation of opposing pressures acting on the chest, is that, during the entire inspiratory act created by the ventilators, the pressure at the alveolar level is equal to zero even if adding together the two ventilators' pressures; thus, the transpulmonary pressure is doubled. The application of this pressure for 1 hour on elderly patients suffering from severe acute respiratory failure, resulted in a significant improvement in blood gas analytical and clinical parameters without any side effects. An increased pulmonary recruitment, including posterior lung areas, and a reduction in spontaneous ventilatory rate have also been demonstrated with PNSV. This also paves the way to the search for the best ventilatory treatment in critically ill or ARDS patients. The compensation of intrathoracic pressures should also lead, although not yet proven, to an improvement in venous return, systolic and cardiac output. In the analysis of the study in which this method was applied, the total transpulmonary pressure delivered was the sum of the individual pressures applied by the two ventilators. However, this does not exclude the possibility of reducing the pressures of the two machines to modulate a lower but balanced total transpulmonary pressure within the chest.

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.

Endothelial shear stress enhancements: a potential solution for critically ill Covid-19 patients

Most critically ill Covid-19 patients succumb to multiple organ failure and/or sudden cardiac arrest (SCA) as a result of comorbid endothelial dysfunction disorders which had probably aggravated by conventional mechanical assist devices. Even worse, mechanical ventilators prevent the respiratory pump from performing its crucial function as a potential generator of endothelial shear stress (ESS) which controls microcirculation and hemodynamics since birth. The purpose of this work is to bring our experience with ESS enhancement and pulmonary vascular resistance (PVR) management as a potential therapeutic solution in acute respiratory distress syndrome (ARDS). We propose a non-invasive device composed of thoracic and infradiaphragmatic compartments that will be pulsated in an alternating frequency (20/40 bpm) with low-pressure pneumatic generator (0.1–0.5 bar). Oxygen supply, nasogastric with, or without endotracheal tubes are considered.

Pneumomediastinum and subcutaneous emphysema in COVID-19: barotrauma or lung frailty?

Background

In mechanically ventilated acute respiratory distress syndrome (ARDS) patients infected with the novel coronavirus disease (COVID-19), we frequently recognised the development of pneumomediastinum and/or subcutaneous emphysema despite employing a protective mechanical ventilation strategy. The purpose of this study was to determine if the incidence of pneumomediastinum/subcutaneous emphysema in COVID-19 patients was higher than in ARDS patients without COVID-19 and if this difference could be attributed to barotrauma or to lung frailty.

Methods

We identified both a cohort of patients with ARDS and COVID-19 (CoV-ARDS), and a cohort of patients with ARDS from other causes (noCoV-ARDS).

Patients with CoV-ARDS were admitted to an intensive care unit (ICU) during the COVID-19 pandemic and had microbiologically confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. NoCoV-ARDS was identified by an ARDS diagnosis in the 5 years before the COVID-19 pandemic period.

Results

Pneumomediastinum/subcutaneous emphysema occurred in 23 out of 169 (13.6%) patients with CoV-ARDS and in three out of 163 (1.9%) patients with noCoV-ARDS (p<0.001). Mortality was 56.5% in CoV-ARDS patients with pneumomediastinum/subcutaneous emphysema and 50% in patients without pneumomediastinum (p=0.46).

CoV-ARDS patients had a high incidence of pneumomediastinum/subcutaneous emphysema despite the use of low tidal volume (5.9±0.8 mL·kg⁻¹ ideal body weight) and low airway pressure (plateau pressure 23±4 cmH₂O).

Conclusions

We observed a seven-fold increase in pneumomediastinum/subcutaneous emphysema in CoV-ARDS. An increased lung frailty in CoV-ARDS could explain this finding more than barotrauma, which, according to its etymology, refers to high transpulmonary pressure.

Pneumomediastinum is more frequent in #COVID19 patients with ARDS despite the use of a protective ventilatory approach. Lung frailty, and not barotrauma, appears to be the main cause of this finding.https://bit.ly/36FQe03

Pre-admission air pollution exposure prolongs the duration of ventilation in intensive care patients

Purpose

Air pollutant exposure constitutes a serious risk factor for the emergence or aggravation of (existing) pulmonary disease. The impact of pre-intensive care ambient air pollutant exposure on the duration of artificial ventilation was, however, not yet established.

Methods

The medical records of 2003 patients, admitted to the intensive care unit (ICU) of the Antwerp University Hospital (Flanders, Belgium), who were artificially ventilated on ICU admission or within 48 h after admission, for the duration of at least 48 h, were analyzed. For each patient’s home address, daily air pollutant exposure [particulate matter with an aerodynamic diameter ≤ 2.5 µm (PM_2.5) and ≤ 10 µm (PM₁₀), nitrogen dioxide (NO₂) and black carbon (BC)] up to 10 days prior to hospital admission was modeled using a high-resolution spatial–temporal model. The association between duration of artificial ventilation and air pollution exposure during the last 10 days before ICU admission was assessed using distributed lag models with a negative binomial regression fit.

Results

Controlling for pre-specified confounders, an IQR increment in BC (1.2 µg/m³) up to 10 days before admission was associated with an estimated cumulative increase of 12.4% in ventilation duration (95% CI 4.7–20.7). Significant associations were also observed for PM_2.5, PM₁₀ and NO₂, with cumulative estimates ranging from 7.8 to 8.0%.

Conclusion

Short-term ambient air pollution exposure prior to ICU admission represents an unrecognized environmental risk factor for the duration of artificial ventilation in the ICU.

Electronic supplementary material

The online version of this article (10.1007/s00134-020-05999-3) contains supplementary material, which is available to authorized users.

"Six-dial Strategy"-Mechanical Ventilation during Cardiopulmonary Resuscitation

As per current guidelines, whenever an advanced airway is in place during cardiopulmonary resuscitation, positive pressure ventilation should be provided without pausing for chest compression. Positive pressure ventilation can be provided through bag-valve resuscitator (BV) or mechanical ventilator (MV), which was found to be equally efficacious. In a busy emergency department, with less trained personnel use of MV is advantageous over BV in terms of reducing human errors and relieving the airway manager to focus on other resuscitation tasks. Currently, there are no guidelines specific to MV settings in cardiac arrest. We present a concept of "six-dial ventilator strategy during CPR" that encompasses the evidence-based settings appropriate during chest compression. We suggest use of volume control ventilation with the following settings: (1) positive end-expiratory pressure of 0 cm of water (to allow venous return), (2) tidal volume of 8 mL/kg with fraction of inspired oxygen at 100% (for adequate oxygenation), (3) respiratory rate of 10 per minute (for adequate ventilation), (4) maximum peak inspiratory pressure or P _max alarm of 60 cm of water (to allow tidal volume delivery during chest compression), (5) switching OFF trigger (to avoid trigger by chest recoil), and (6) inspiratory to expiratory time ratio of 1:5 (to provide adequate inspiratory time of 1 second). How to cite this article: Sahu AK, Timilsina G, Mathew R, Jamshed N, Aggarwal P. "Six-dial Strategy"-Mechanical Ventilation during Cardiopulmonary Resuscitation. Indian J Crit Care Med 2020;24(6):487-489.

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.

A rapid shallow breathing index threshold of 85 best predicts extubation success in chronic obstructive pulmonary disease patients with hypercapnic respiratory failure

Background

The rapid shallow breathing index (RSBI) is used clinically to help predict a patient's likelihood of successful liberation from mechanical ventilation (MV). However, the traditional threshold (<105 breaths/min/L) may underperform in patients with chronic obstructive pulmonary disease (COPD). We sought to determine the optimal RSBI threshold for COPD patients to improve the diagnostic accuracy for predicting successful ventilator liberation.

Methods

This was a prospective observational multicenter study of COPD patients [according to Global initiative for Chronic Obstructive Lung Disease (GOLD) criteria] admitted to the Medical ICUs of eight academic medical centers. All patients were intubated for hypercapnic respiratory failure and met the American Thoracic Society/European Respiratory Society guidelines to participate in a weaning trial. Ventilator weaning was conducted according to a defined protocol. RSBI was measured through the ventilator after 120 minutes of spontaneous breathing trial (SBT).

Results

Ninety patients were included (39 males and 51 females). Forty-three patients (48%) were successfully extubated whereas 47 patients (52%) failed extubation. Significant differences were observed between groups for duration-of-intubation [duration of intubation (DoI); P<0.0001], spontaneous tidal volume (VT) (P=0.03), and the ratio of dynamic-to-static compliance (P=0.005). The RSBI threshold of ≤85 breaths/min/L performed best: area under curve (AUC) receiver operating characteristic (ROC) curves 0.91, sensitivity 95.6%, specificity 90.4%, positive predictive value (PPV) 95.5%, and negative predictive value (NPV) 90.6%., positive likelihood ratio (LR+) 5.48, negative likelihood ratio (LR-) 0.25, and the diagnostic accuracy 91.7%. In post-ROC analyses, DoI and hospital length-of-stay (LOS) did not impact performance.

Conclusions

In COPD patients intubated with hypercapnia, RSBI ≤85 breaths/min/L outperformed the widely used threshold <105 breaths/min/L, yielding a 95.5% probability of extubation success, independent of ventilation duration or hospital LOS.

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.