Negative-Pressure Pulmonary Edema

Severe postoperative negative pressure pulmonary edema: a case report

BACKGROUND

Postoperative negative pressure pulmonary edema (NPPE) can occur in any patient undergoing general anesthesia. There are several risk factors for it, especially postoperative laryngospasm. The disease is usually benign and quickly reversible. In our case the severity and need for advanced critical care therapy was unusual.

CASE

We report a severe case of postoperative negative pressure pulmonary edema in a 62-year-old male patient undergoing elective right-sided retroperitoneoscopic adrenalectomy. The patient developed a severe case of acute respiratory distress syndrome (ARDS) after postoperative laryngospasm, possibly in conjunction with a suspected anaphylactic reaction. The patient was consequently treated with a combination of invasive airway pressure release ventilation (APRV) and a prone positioning regimen. After drastic improvement in respiratory function, the patient was discharged from the intensive care unit after 10 days and from the hospital after 14 days.

CONCLUSION

NPPE is a rare but relevant complication of anesthesia and laryngospasm. The disease can basically occur in any patient undergoing general anesthesia and therefore should be considered.

Extubation-Related Complications

Extubation represents an essential component of airway management. While being a common procedure in anesthesiology and critical care medicine, it is accompanied by a significant risk of morbidity and mortality. Safe extubation requires considerable skills, risk stratification and advanced planning. It is important to emphasize that intentional extubation is always an elective procedure, and as such should only be executed when conditions are optimal. The purpose of this review is to discuss the complications associated with planned extubation in the adult patient, including risk factors and management strategies, mainly focusing on the postoperative setting.

Cogent integration of inflammatory biomarkers and perioperative complications of thyroid surgery in thyroidology

OBJECTIVE

Back to the sources, postoperative nausea and vomiting, hypo- and hypertension, heart rate alterations, and hypoxemia due to laryngospasm might be considered perioperative complications.

METHODS

This cross-sectional study was conducted at an Education and Research Hospital between January 2018 and June 2023. The study included a total of 437 cases of thyroid surgery. The demographic data such as age, sex, co-morbidities of the instances, hypotension, hypertension, bradycardia, hypoxemia, and postoperative nausea and vomiting, as well as laboratory data were obtained and analyzed.

RESULTS

Of 437 cases, 334 (76%) were females and 103 (24%) were males, with a mean age of 51.83±11.91 years and 55.32±11.87 years, respectively. No statistical significance was realized between the complications, co-morbid diseases, and age. Notably, no liaison between the complications after awakening from the anesthesia and preoperative laboratory parameters was discerned. However, a high but no significant relationship was revealed between the platelet-to-lymphocyte ratio (P/L) in cases with hypoxemia and hypotension. Finally, no significance between laboratory values, bradycardia, hypertension, and postoperative nausea and vomiting was distinguished.

CONCLUSION

We postulate that the so-called inflammatory biomarkers measured at the time of preoperative examination in the blood count concept selectively do not enrich for anticipating complications that arise in the perioperative echelon.

Negative-Pressure Pulmonary Edema Induced by Flexible Bronchoscopy: A Case Report

Negative-pressure pulmonary edema (NPPE) arises from excessive inspiratory effort due to upper airway obstruction, often associated with postoperative laryngospasm and upper airway infections like epiglottitis. We present a case of NPPE during bronchoscopy. A 45-year-old female patient, who was undergoing bronchoscopy for interstitial pneumonia evaluation, was examined using a tracheal tube with a 7.5 mm internal diameter and a bronchoscope with a 5.9 mm external diameter. The patient's respiratory condition gradually worsened after intubation. We continued with the examination, supplying approximately 5 L/min of oxygen through the intubation tube. We performed an alveolar lavage, and the recovered fluid gradually turned pale and bloody. After the examination, the patient continued to expectorate pink and frothy sputum and prolonged respiratory failure. Chest radiography revealed new extensive bilateral infiltrates. We ruled out cardiogenic causes through clinical examination, electrocardiogram (ECG), and transthoracic echocardiography. As a result, we suspected that temporary upper airway obstruction during bronchoscopy led to NPPE. Applying continuous positive airway pressure (CPAP) quickly improved the pulmonary edema. The risk of NPPE during bronchoscopy needs to be acknowledged, especially when using larger bronchoscopes and smaller tracheal tubes.

Bedside ultrasound in post-anaesthetic care unit for the diagnosis of post-extubation negative pressure pulmonary oedema: A paediatric case

BACKGROUND

Post-extubation negative pressure pulmonary oedema is a rare, potentially life-threatening complication associated with general anaesthesia. Chest radiography is used as a diagnostic tool, but it implies a non-negligible radiation exposure, a very important consideration, especially for the paediatric population. However, lung ultrasound can overcome this problem and can be used to detect postoperative pulmonary complications.

CASE REPORT

A 16-year-old male was scheduled for tympanoplasty. General anaesthesia was conducted, and after extubation, the patient developed a laryngospasm. On arrival at the post-anaesthetic care unit, the patient started to cough, a pink frothy sputum and hypoxemia were noticed, and auscultation revealed crepitations. A bedside lung ultrasound showed more than three B-lines per intercostal window, suggesting an alveolar-interstitial syndrome.

DISCUSSION

With this case report, we would like to raise awareness to this clinical entity and demonstrate bedside ultrasound has an important role in the diagnostic and therapeutic assessment during the perioperative period.

Respiratory drive: a journey from health to disease

Respiratory drive is defined as the intensity of respiratory centers output during the breath and is primarily affected by cortical and chemical feedback mechanisms. During the involuntary act of breathing, chemical feedback, primarily mediated through CO2, is the main determinant of respiratory drive. Respiratory drive travels through neural pathways to respiratory muscles, which execute the breathing process and generate inspiratory flow (inspiratory flow-generation pathway). In a healthy state, inspiratory flow-generation pathway is intact, and thus respiratory drive is satisfied by the rate of volume increase, expressed by mean inspiratory flow, which in turn determines tidal volume. In this review, we will explain the pathophysiology of altered respiratory drive by analyzing the respiratory centers response to arterial partial pressure of CO2 (PaCO2) changes. Both high and low respiratory drive have been associated with several adverse effects in critically ill patients. Hence, it is crucial to understand what alters the respiratory drive. Changes in respiratory drive can be explained by simultaneously considering the (1) ventilatory demands, as dictated by respiratory centers activity to CO2 (brain curve); (2) actual ventilatory response to CO2 (ventilation curve); and (3) metabolic hyperbola. During critical illness, multiple mechanisms affect the brain and ventilation curves, as well as metabolic hyperbola, leading to considerable alterations in respiratory drive. In critically ill patients the inspiratory flow-generation pathway is invariably compromised at various levels. Consequently, mean inspiratory flow and tidal volume do not correspond to respiratory drive, and at a given PaCO2, the actual ventilation is less than ventilatory demands, creating a dissociation between brain and ventilation curves. Since the metabolic hyperbola is one of the two variables that determine PaCO2 (the other being the ventilation curve), its upward or downward movements increase or decrease respiratory drive, respectively. Mechanical ventilation indirectly influences respiratory drive by modifying PaCO2 levels through alterations in various parameters of the ventilation curve and metabolic hyperbola. Understanding the diverse factors that modulate respiratory drive at the bedside could enhance clinical assessment and the management of both the patient and the ventilator.

Negative pressure pulmonary edema following laryngospasm after dental abscess: A case report

Negative pressure pulmonary edema (NPPE), also known as post-obstructive pulmonary edema, is a rare and life-threatening condition. It occurs when a person breathes against an obstructed glottis, causing negative thoracic pressure in the lungs. This negative pressure can lead to fluid accumulation in the lungs, resulting in pulmonary edema. The obstructed glottis might be caused by laryngospasm, which occurs when the muscles around the larynx involuntarily spasm and can lead to complete upper airway occlusion. This report shares the case of a 33-year-old woman hospitalized for periapical dental abscess, facial swelling, and shortness of breath. The patient exhibited signs of poor oral hygiene. After the exacerbation of her symptoms, she showed signs of asphyxia and decreased oxygen saturation, which led to her intubation. Imaging revealed bilateral pleural effusion and patchy ground glass opacities favoring NPPE. After three days of treatment with diuretics and other conservative measures, her condition was alleviated, and she was extubated. Laryngospasm in the presence of a dental abscess is uncommon. Identification of imaging favoring NPPE in this setting is even more rare. In cases of laryngospasm, prompt intubation is crucial. Therapy with diuretics and other conservative measures can effectively treat NPPE following laryngospasm.

Negative pressure plmonary oedema after adenotonsillectom: a case report and litrature review

Background

Negative pressure pulmonary is a non-cardiogenic pulmonary oedema that can occur after reliving of upper airway obstruction. It is life threatening clinical scenario developed due to increase intrathoracic pressure during marked inspiratory effort against a closed glottis.

Case presentation

A successful adenotonsillectomy was done for a healthy 12-year-old, 33 kg male patient and transferred to post-anaesthesia care unit. In the unit the patient developed signs and symptoms of negative pressure pulmonary oedema so he was treated with diuretics and oxygen while restricting fluid. However, the dyspnoea was persisted so he was transferred to ICU.

Clinical discussion

This case report shows the development of negative pressure pulmonary oedema after adenotonsillectomy. In this report the clinical presentation, diagnosis, treatment, prevention and prognosis of negative pressure pulmonary oedema after adenotonsillectomy was discussed in detail with citing updated evidences.

Conclusions

Post-extubation pulmonary oedema can occur after reliving of chronic air obstruction. Usually it occur within 5 min after reliving the obstruction but it can occur at any time. All healthcare professionals must be knowledgeable about clinical presentation and managements of negative pressure pulmonary oedema.

Negative pressure pulmonary edema after laparoscopic cholecystectomy: A case report and literature review

RATIONALE

Negative pressure pulmonary edema (NPPE) is an acute onset of non-cardiogenic interstitial pulmonary edema, commonly seen among surgical patients after extubation from general aneasthesia. It is mainly caused by rapid inspiration with acute upper airway obstruction resulting in significant negative thoracic pressure.

PATIENT CONCERNS

A 24-year-old female patient who underwent laparoscopic cholecystectomy under general anesthesia and developed NPPE postoperatively.

DIAGNOSES

Her main clinical manifestation was coughing up pink foamy sputum; postoperative CT showed increased texture in both lungs and bilateral ground glass opacities.

INTERVENTIONS

Diuretics and steroids were used, and symptomatic supportive treatments such as oxygen were given.

OUTCOMES

After treatment, on the fourth post-operative day, her symptoms were relieved and her vital signs were stable enough for her to be discharged.

LESSONS

Although this is a rare and severe complication, the prognosis of NPPE is good when it is managed with proper diagnosis and treatment.

Negative-pressure pulmonary edema following maxillofacial surgery: recognize to prevent further complications

Negative-pressure pulmonary edema (NPPE) is a rare respiratory complication due to acute upper airway obstruction occurring shortly after extubation. We report a case of NPPE in young adult patient who underwent an eventful general anesthesia. The patient presented laryngospasm followed by acute respiratory distress with pink frothy sputum. The NPPE was initially misdiagnosed, and a preventable tracheostomy was performed. NPPE was managed with mechanical ventilation and diuretics, and the patient had full recovery. Every anesthesiologist should be aware of the diagnosis of NPPE. Early recognition and management are essential to prevent the morbidity associated with NPPE in young healthy patients.

Postmortem computed tomography imaging of negative pressure pulmonary edema induced by rice cakes: A case report

Airway obstruction by foreign bodies or laryngospasms often results in negative pressure pulmonary edema (NPPE). NPPE can develop despite the removal of airway obstruction. This is well-known among clinicians, particularly anesthesiologists, emergency physicians, pediatricians, and radiologists. Computed tomography (CT) features of NPPE include diffuse central ground-glass opacities and thickening of the bronchovascular bundles and bronchial walls. NPPE can also occur after strangulation or smothering with a plastic bag, and is sometimes fatal. Nevertheless, no reports of NPPE are available in forensic journals, and forensic practitioners may not be dedicating the necessary attention to this condition. Recently, the use of postmortem CT as an auxiliary imaging modality for autopsies has increased among forensic institutions in Japan. Understanding the mechanisms and CT findings of NPPE will be useful for forensic practitioners. Herein, we present a case wherein the postmortem CT image revealed NPPE resulting from the obstruction of the airway induced by rice cakes.

Pediatric negative pressure pulmonary edema: Case series and review of the literature

INTRODUCTION

Negative pressure pulmonary edema (NPPE) is a potentially life-threatening complication that develops rapidly following acute upper airway obstruction. The condition is rare, dramatic but resolves quickly. Prompt recognition and appropriate supportive treatment may prevent unnecessary investigations and iatrogenic complications.

METHODS

We describe a spectrum of etiologies and clinical manifestation of pediatric NPPE in our center and review of previous publications.

CONCLUSION

The etiology for the development of NPPE in children has shifted over the years. Although dramatic in presentation, this type of pulmonary edema often resolves quickly with minimal support.

The prognostic value of red blood cell distribution width for pulmonary infection in elderly patients received abdominal surgery with tracheal intubation and general anesthesia

BACKGROUND

Red blood cell distribution width (RDW) has been shown to be an important predictor of the occurrence of various inflammatory and infectious diseases. However, the predictive value of RDW for pulmonary infection in elderly patients undergoing abdominal surgery under general anesthesia with endotracheal intubation remains unclear.

METHODS

A total of 200 eligible elderly patients who underwent abdominal surgery with endotracheal intubation and general anesthesia in our hospital from January 2019 to January 2022 were included in this study. During hospitalization, there were 64 cases with different degrees of pulmonary infection, and 136 cases without pulmonary infection. Participants' RDW levels were analyzed on admission. Serum levels of inflammatory factors in infected patients were analyzed during hospitalization. Multivariate logistic analysis was performed to evaluate clinical factors for pulmonary infection during hospitalization following-up abdominal surgery with endotracheal intubation and general anesthesia in elderly patients. Youden's J statistic was used to define the correlation.

RESULTS

RDW at admission was independently associated with the risk of pulmonary infection in elderly patients undergoing general anesthesia with endotracheal intubation for abdominal surgery ([OR 1.952, 95% confidence interval 1.604 to 2.279, p=0.006]). RDW at admission was statistically positively correlated with inflammatory factors, including procalcitonin (p<0.001), C-reactive protein (p<0.001), and tumor necrosis factor-α (p<0.001), in elderly patients with postoperative pneumonia who underwent abdominal surgery.

CONCLUSION

RDW at admission had predictive value for pulmonary infection in elderly patients undergoing abdominal surgery under general anesthesia with endotracheal intubation.

Negative pressure pulmonary edema (Review)

Negative pressure pulmonary edema (NPPE) is a complication resulting from acute or chronic upper airway obstruction, often posing challenges in recognition and diagnosis for clinicians. If left untreated, NPPE can lead to hypoxemia, heart failure and even shock. Furthermore, the drug treatment of NPPE remains a subject of controversy. The primary pathophysiological mechanism of NPPE involves the need for high inspiratory pressure to counteract upper airway obstruction, subsequently causing a progressive rise in negative pressure within the pleural cavity. Consequently, this results in increased pulmonary microvascular pressure, leading to the infiltration of pulmonary capillary fluid into the alveoli. NPPE exhibits numerous risk factors and causes, with laryngospasm following anesthesia and extubation being the most prevalent. The diagnosis of NPPE often presents challenges due to confusion with conditions such as gastroesophageal reflux or cardiogenic pulmonary edema, given the similarity in initial factors triggering both diseases. Upper airway patency, positive pressure non-invasive ventilation, supplemental oxygen and re-intubation mechanical ventilation are the foundation of the treatment of NPPE. The present review aims to discuss the etiology, clinical presentation, pathophysiology and management of NPPE.

Severe hypoxemia after extubation secondary to myxedema coma: a case report

Myxedema coma is a rare and life-threatening endocrine emergency characterized by abnormalities in multiple organ systems. A 32-year-old woman with prolonged undiagnosed severe hypothyroidism was referred to our hospital owing to lower abdominal pain and menopause for more than 3 months. She underwent exploratory laparotomy and induced abortion under general anesthesia, and developed severe hypoxemia after extubation. She was diagnosed with myxedema coma, and was subsequently discharged with a good prognosis following treatment. This case suggests that myxedema coma should be considered a potential etiology of peri-operative hypoxemia. The findings in this case emphasize the importance of anesthesiologists' comprehensive understanding of myxedema coma. Prompt diagnosis followed by treatment is essential to reduce the mortality rate associated with this condition.

Fluid management strategies and their interaction with mechanical ventilation: from experimental studies to clinical practice

Patients on mechanical ventilation may receive intravenous fluids via restrictive or liberal fluid management. A clear and objective differentiation between restrictive and liberal fluid management strategies is lacking in the literature. The liberal approach has been described as involving fluid rates ranging from 1.2 to 12 times higher than the restrictive approach. A restrictive fluid management may lead to hypoperfusion and distal organ damage, and a liberal fluid strategy may result in endothelial shear stress and glycocalyx damage, cardiovascular complications, lung edema, and distal organ dysfunction. The association between fluid and mechanical ventilation strategies and how they interact toward ventilator-induced lung injury (VILI) could potentiate the damage. For instance, the combination of a liberal fluids and pressure-support ventilation, but not pressure control ventilation, may lead to further lung damage in experimental models of acute lung injury. Moreover, under liberal fluid management, the application of high positive end-expiratory pressure (PEEP) or an abrupt decrease in PEEP yielded higher endothelial cell damage in the lungs. Nevertheless, the translational aspects of these findings are scarce. The aim of this narrative review is to provide better understanding of the interaction between different fluid and ventilation strategies and how these interactions may affect lung and distal organs. The weaning phase of mechanical ventilation and the deresuscitation phase are not explored in this review.

A Complex Presentation of Acute Postoperative Negative-Pressure Pulmonary Edema: A Case Report and Review of Literature

Negative-pressure pulmonary edema (NPPE) is an uncommon diagnosis that requires a high clinical suspicion to recognize and manage and has high morbidity and mortality. It usually results secondary to markedly negative intrapleural pressure due to the forceful inspiration against the obstructed airway from upper airway infection, tumor, or laryngospasm. We present a case of a 27-year-old female with morbid obesity who underwent sleeve gastrectomy and developed NPPE upon emergence from anesthesia. The focus of supportive care should be on addressing the obstruction in the upper airway through either endotracheal intubation or cricothyroidotomy. Additionally, it is important to initiate lung-protective positive-pressure ventilation and promote diuresis, unless the patient is in a state of shock. The resolution of pulmonary edema is typically swift, partially due to the preservation of alveolar fluid clearance mechanisms. In the literature review, we delve into the clinical presentation, pathophysiology, and management of NPPE or post-obstructive pulmonary edema.

Surgical management of a laryngeal rhabdomyosarcoma in a cat

Case summary

An 11-year-old male castrated British Shorthair was referred for investigations into an upper respiratory tract mass. A partial laryngectomy was performed to excise the mass. Marginal resection of the mass involved excision of parts of the thyroid cartilage and left arytenoid cartilage. A tracheostomy tube was maintained for 48 h postoperatively. The cat recovered without complication and was discharged at 72 h postoperatively. Histopathology of the mass was deemed most consistent with a rhabdomyosarcoma (RMS).

Relevance and novel information

Telephone follow-up 12 months postoperatively confirmed resolution of the clinical signs. To our knowledge, this is the first report of a laryngeal RMS in a cat. RMS should be considered a differential diagnosis for a laryngeal mass in a cat. This case demonstrates that resection via a partial laryngectomy may be a viable therapeutic option.

Hiccup-like Contractions in Mechanically Ventilated Patients: Individualized Treatment Guided by Transpulmonary Pressure

Hiccups-like contractions, including hiccups, respiratory myoclonus, and diaphragmatic tremor, refer to involuntary, spasmodic, and inspiratory muscle contractions. They have been repeatedly described in mechanically ventilated patients, especially those with central nervous damage. Nevertheless, their effects on patient-ventilator interaction are largely unknown, and even more overlooked is their contribution to lung and diaphragm injury. We describe, for the first time, how the management of hiccup-like contractions was individualized based on esophageal and transpulmonary pressure measurements in three mechanically ventilated patients. The necessity or not of intervention was determined by the effects of these contractions on arterial blood gases, patient-ventilator synchrony, and lung stress. In addition, esophageal pressure permitted the titration of ventilator settings in a patient with hypoxemia and atelectasis secondary to hiccups and in whom sedatives failed to eliminate the contractions and muscle relaxants were contraindicated. This report highlights the importance of esophageal pressure monitoring in the clinical decision making of hiccup-like contractions in mechanically ventilated patients.

An Internist's Approach to a Case of Negative Pressure Pulmonary Edema: A Rare Cause of Noncardiogenic Pulmonary Edema

Negative-pressure pulmonary edema (NPPE) is a rare cause of noncardiogenic pulmonary edema, which usually presents postoperatively. Its pathophysiology is mostly described as a profound negative intrathoracic pressure caused by an airway obstruction such as laryngospasm, which may occur during extubation. But, there are other hypotheses about it, such as catecholamines release causing an elevated hydrostatic pressure in the cardiopulmonary circuit and, consequently, a major capillary leak to the interstitium. Its natural course varies, from prompt recovery to intensive care unit escalation and prolonged mechanical ventilation. Although anesthesiologists often detect this condition, this case's objective is to bring awareness of this condition to internists as a potential differential diagnosis for hypoxia in the postoperative setting.

Patient Self-Inflicted Lung Injury-A Narrative Review of Pathophysiology, Early Recognition, and Management Options

Patient self-inflicted lung injury (P-SILI) is a life-threatening condition arising from excessive respiratory effort and work of breathing in patients with lung injury. The pathophysiology of P-SILI involves factors related to the underlying lung pathology and vigorous respiratory effort. P-SILI might develop both during spontaneous breathing and mechanical ventilation with preserved spontaneous respiratory activity. In spontaneously breathing patients, clinical signs of increased work of breathing and scales developed for early detection of potentially harmful effort might help clinicians prevent unnecessary intubation, while, on the contrary, identifying patients who would benefit from early intubation. In mechanically ventilated patients, several simple non-invasive methods for assessing the inspiratory effort exerted by the respiratory muscles were correlated with respiratory muscle pressure. In patients with signs of injurious respiratory effort, therapy aimed to minimize this problem has been demonstrated to prevent aggravation of lung injury and, therefore, improve the outcome of such patients. In this narrative review, we accumulated the current information on pathophysiology and early detection of vigorous respiratory effort. In addition, we proposed a simple algorithm for prevention and treatment of P-SILI that is easily applicable in clinical practice.

Noncardiogenic pulmonary edema in small animals

OBJECTIVE

To review various types of noncardiogenic pulmonary edema (NCPE) in cats and dogs.

ETIOLOGY

NCPE is an abnormal fluid accumulation in the lung interstitium or alveoli that is not caused by cardiogenic causes or fluid overload. It can be due to changes in vascular permeability, hydrostatic pressure in the pulmonary vasculature, or a combination thereof. Possible causes include inflammatory states within the lung or in remote tissues (acute respiratory distress syndrome [ARDS]), airway obstruction (post-obstructive pulmonary edema), neurologic disease such as head trauma or seizures (neurogenic pulmonary edema), electrocution, after re-expansion of a collapsed lung or after drowning.

DIAGNOSIS

Diagnosis of NCPE is generally based on history, physical examination, and diagnostic imaging. Radiographic findings suggestive of NCPE are interstitial to alveolar pulmonary opacities in the absence of signs of left-sided congestive heart failure or fluid overload such as cardiomegaly or congested pulmonary veins. Computed tomography and edema fluid analysis may aid in the diagnosis, while some forms of NCPE require additional findings to reach a diagnosis.

THERAPY

The goal of therapy for all types of NCPE is to preserve tissue oxygenation and reduce the work of breathing. This may be achieved by removing the inciting cause (eg, airway obstruction) and cage rest in mild cases and supplemental oxygen in moderate cases and may require mechanical ventilation in severe cases.

PROGNOSIS

Prognosis is generally good for most causes of veterinary NCPE except for ARDS, although data are scarce for some etiologies of NCPE.

Advantages and drawbacks of helmet noninvasive support in acute respiratory failure

INTRODUCTION

Non-invasive ventilation (NIV) represents an effective strategy for managing acute respiratory failure. Facemask NIV is strongly recommended in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) with hypercapnia and acute cardiogenic pulmonary edema (ACPE). Its role in managing acute hypoxemic respiratory failure (AHRF) remains a debated issue. NIV and continuous positive airway pressure (CPAP) delivered through the helmet are recently receiving growing interest for AHRF management.

AREAS COVERED

In this narrative review, we discuss the clinical applications of helmet support compared to the other available noninvasive strategies in the different phenotypes of acute respiratory failure.

EXPERT OPINION

Helmets enable the use of high positive end-expiratory pressure, which may protect from self-inflicted lung injury: in AHRF, the possible superiority of helmet support over other noninvasive strategies in terms of clinical outcome has been hypothesized in a network metanalysis and a randomized trial, but has not been confirmed by other investigations and warrants confirmation. In AECOPD patients, helmet efficacy may be inferior to that of face masks, and its use prompts caution due to the risk of CO₂ rebreathing. Helmet support can be safely applied in hypoxemic patients with ACPE, with no advantages over facemasks.

Spontaneous Breathing and Pendelluft in Patients with Acute Lung Injury: A Narrative Review

Acute respiratory distress syndrome (ARDS) is characterized by acute-onset rapid-deteriorating inflammatory lung injury. Although the preservation of spontaneous breathing may have physiological benefits in oxygenation, increasing evidence shows that vigorous spontaneous breathing may aggravate lung injury (i.e., patient self-inflicted lung injury). Increased lung stress and pendelluft, which is defined as intrapulmonary gas redistribution without a significant change in tidal volume, are important mechanisms of patient self-inflicted lung injury. The presence of pendelluft may be considered a surrogate marker of vigorous inspiratory effort, which can cause the dependent lung to overstretch. In this review, we summarized three major methods for electrical impedance tomography-based pendelluft monitoring. Future studies are warranted to compare and validate the different methods of pendelluft estimation in patients with ARDS.

Negative-pressure pulmonary edema after upper airway obstruction during transesophageal echocardiogram

Negative-pressure pulmonary edema (NPPE) has become a well-recognized, though uncommon, complication of acute upper airway obstruction. While initially described in the setting of peri-operative endotracheal intubation, NPPE has been increasingly observed in numerous other clinical scenarios. In this report, we describe a case of NPPE that occurred after a scheduled cardioversion and transesophageal echocardiogram (TEE). We suspect the attempt at TEE probe placement inadvertently led to tracheal insertion as suggested by excessive resistance, poor visualization, stridor, and subsequent acute pulmonary edema. While supportive treatment when recognized can lead to rapid improvement, it is important to recognize NPPE as a possible complication of this commonly indicated procedure.

Learning objective

Excessive resistance is a common challenge during the transesophageal echocardiogram (TEE) procedure and may be the result of incidental tracheal insertion. Negative-pressure pulmonary edema (NPPE) may result from this acute upper airway obstruction. Thus, NPPE should be on the differential for patients who present with unexplained non-cardiogenic pulmonary edema and should be recognized as a possible complication of the TEE procedure.

„Negativdruck-Lungenödem“ und „alveoläre Hämorrhagie“ als Komplikationen einer oberen Atemwegsobstruktion

Negativdruck-Lungenödem und alveoläre Hämorrhagie sind lebensbedrohliche Komplikationen infolge einer akuten oberen Atemwegsobstruktion. Durch die Obstruktion im Larynx-/Pharynbereich kommt es zu hohen negativen Intrapleuraldrucken, die sich, durch unterschiedliche Faktoren bedingt, auf die Integrität der alveolo-kapillären Membran auswirken. In der Übersichtsarbeit werden klinische Symptome, Ätiologie, die Pathophysiologie sowie die therapeutischen Optionen beschrieben. Ziel ist es, den Kliniker mit den Krankheitsbildern und den Komplikationen vertraut zu machen.

Near Hanging: Evaluation and Management

Prior to the COVID-19 pandemic, the incidence of self-harm was already on the rise. Hanging/suffocation accounted for 50% of the increase in suicide attempts and remains the second leading cause of death from self-harm in the United States. Studies on the management of near-hanging patients are lacking, and most published literature is retrospective. Following airway and circulation assessment, clinical examination and imaging, namely CT angiography, remain the standard for identifying the injuries associated with near hanging: cervical spine fracture, blunt cerebrovascular injury, laryngeal injury, and injury to the trachea and oropharynx. These injuries, however, are uncommon, and each occur in < 5% of patients in most series. In a large series of critically ill near-hanging patients, > 50% survived to hospital discharge; however, cardiac arrest predicted a poor outcome. The management of asphyxia-related arrest remains controversial. Targeted temperature management has only been studied in a single large multicenter trial, which was retrospective. Given the significant selection bias of targeted temperature management in the treatment of the most ill patients, no firm recommendations can be made. Finally, for survivors, the underlying mental health issues must be addressed to avoid recurrent suicide attempts. Thirty percent of patients in a large near-hanging series were admitted for their second suicide attempt.

Non-invasive ventilation for acute hypoxemic respiratory failure, including COVID-19

Optimal initial non-invasive management of acute hypoxemic respiratory failure (AHRF), of both coronavirus disease 2019 (COVID-19) and non-COVID-19 etiologies, has been the subject of significant discussion. Avoidance of endotracheal intubation reduces related complications, but maintenance of spontaneous breathing with intense respiratory effort may increase risks of patients' self-inflicted lung injury, leading to delayed intubation and worse clinical outcomes. High-flow nasal oxygen is currently recommended as the optimal strategy for AHRF management for its simplicity and beneficial physiological effects. Non-invasive ventilation (NIV), delivered as either pressure support or continuous positive airway pressure via interfaces like face masks and helmets, can improve oxygenation and may be associated with reduced endotracheal intubation rates. However, treatment failure is common and associated with poor outcomes. Expertise and knowledge of the specific features of each interface are necessary to fully exploit their potential benefits and minimize risks. Strict clinical and physiological monitoring is necessary during any treatment to avoid delays in endotracheal intubation and protective ventilation. In this narrative review, we analyze the physiological benefits and risks of spontaneous breathing in AHRF, and the characteristics of tools for delivering NIV. The goal herein is to provide a contemporary, evidence-based overview of this highly relevant topic.

Helmet noninvasive support for acute hypoxemic respiratory failure: rationale, mechanism of action and bedside application

Introduction

Helmet noninvasive support may provide advantages over other noninvasive oxygenation strategies in the management of acute hypoxemic respiratory failure. In this narrative review based on a systematic search of the literature, we summarize the rationale, mechanism of action and technicalities for helmet support in hypoxemic patients.

Main results

In hypoxemic patients, helmet can facilitate noninvasive application of continuous positive-airway pressure or pressure-support ventilation via a hood interface that seals at the neck and is secured by straps under the arms. Helmet use requires specific settings. Continuous positive-airway pressure is delivered through a high-flow generator or a Venturi system connected to the inspiratory port of the interface, and a positive end-expiratory pressure valve place at the expiratory port of the helmet;  alternatively, pressure-support ventilation is delivered by connecting the helmet to a mechanical ventilator through a bi-tube circuit. The helmet interface allows continuous treatments with high positive end-expiratory pressure with good patient comfort. Preliminary data suggest that helmet noninvasive ventilation (NIV) may provide physiological benefits compared to other noninvasive oxygenation strategies (conventional oxygen, facemask NIV, high-flow nasal oxygen) in non-hypercapnic patients with moderate-to-severe hypoxemia (PaO₂/FiO₂ ≤ 200 mmHg), possibly because higher positive end-expiratory pressure (10–15 cmH₂O) can be applied for prolonged periods with good tolerability. This improves oxygenation, limits ventilator inhomogeneities, and may attenuate the potential harm of lung and diaphragm injury caused by vigorous inspiratory effort. The potential superiority of helmet support for reducing the risk of intubation has been hypothesized in small, pilot randomized trials and in a network metanalysis.

Conclusions

Helmet noninvasive support represents a promising tool for the initial management of patients with severe hypoxemic respiratory failure. Currently, the lack of confidence with this and technique and the absence of conclusive data regarding its efficacy render helmet use limited to specific settings, with expert and trained personnel. As per other noninvasive oxygenation strategies, careful clinical and physiological monitoring during the treatment is essential to early identify treatment failure and avoid delays in intubation.

Research Progress on the Mechanism of Right Heart-Related Pulmonary Edema

Objective. To investigate the mechanisms underlying the development of right heart-associated PE. Background. Right heart-related pulmonary edema (PE) refers to PE resulting from impaired right heart function caused by primary or secondary factors, which is common in critically ill patients. Although the clinical manifestations of different types of right heart-related PE are similar, the pathophysiological changes and treatment methods are significantly different. According to the hemodynamic mechanism, right heart-related PE is primarily classified into two types. One is the increase of right heart flow, including extravascular compression, intravascular compression, cardiac compression, and cardiac decompression. The other type is the abnormal distribution of pulmonary circulation, including obstruction, resistance, pleural decompression, or negative pressure. With the development of hemodynamic monitoring, hemodynamic data not only help us understand the specific pathogenesis of right heart-related PE but also assist us in determining the direction of therapy and enabling individualized treatment. Summary. This article presents a review on right heart-associated PE, with a perspective of hemodynamic analysis, and emphasizes the importance of right heart function in the management of circulation. Understanding the mechanism of right heart-associated PE will not only aid in better monitoring right heart function but also help intensivists make a more accurate identification of various types of PE in the clinic.

Unexpected pulmonary edema and cardiac arrest following wedge resection of spontaneous pneumothorax -A case report-

Background

Reexpansion pulmonary edema is a rare but potentially lethal complication. We report a case of suspected reexpansion pulmonary edema that led to cardiac arrest.

Case

A 16-year-old male patient underwent wedge resection due to right pneumothorax. The patient showed pink frothy sputum three hours following surgery, and a chest x-ray showed right unilateral pulmonary edema. Thirteen hours following surgery, the patient continuously showed pink frothy sputum and presented with severe hypoxemia, tachypnea, and tachycardia. After transferring to the intensive care unit (ICU), he developed ventricular tachycardia. Cardiopulmonary resuscitation was performed for 32 min. Chest X-ray showed diffuse bilateral pulmonary edema. Extracorporeal membrane oxygenation was performed. During the 65 days of ICU care, the patient became mentally alert. However, follow-up echocardiography revealed severe heart failure.

Conclusions

Rexpansion pulmonary edema can rapidly progress to diffuse bilateral pulmonary edema. Therefore, careful observation is required for the patients who show signs of pulmonary edema after reexpansion.

Imaging characteristics and mechanism of negative pressure pulmonary edema in children: three case reports

This article reports three children who presented with negative pressure pulmonary oedema before or after removal of the airway foreign bodies. Of them, two cases were type I negative pressure pulmonary oedema and one case was type II negative pressure pulmonary oedema following foreign body removal from the airways. Pathogenesis and location differences between type I and type II negative pressure pulmonary oedema caused by airway foreign body obstruction, as well as diagnosis and treatment modalities of the negative pressure pulmonary oedema were discussed.

High-PEEP Noninvasive Ventilation By Means of Mask as the Respiratory Support in COVID-19 ARDS Patients: Experience From General Hospital Slavonski Brod

OBJECTIVE

Despite widespread use of noninvasive ventilation (NIV) in some coronavirus disease 2019 (COVID-19) hypoxemic patients, its clinical application is still subject of debate.

METHODS

This is a retrospective, observational study with data collected from 91 consecutive patients treated in COVID intensive care unit (ICU) in our institution between October 2020 and February 2021. Outcomes were represented as ventilation hours, ICU and hospital length of stay, and ICU and hospital mortality.

RESULTS

Patients' mean age was 66 ± 11 y and severe COVID-19 pneumonia with mean paO₂/FiO₂ 137 ± 57 was observed in 90% of the patients. High positive end-expiratory pressure (PEEP) NIV by means of total face mask was initially applied in 58 (64%) patients, high flow oxygen therapy (HFOT) in 25 (27%) patients, whilst invasive mechanical ventilation (IMV) started at the moment of admission in 8 (9%) patients. NIV and high flow oxygen therapy (HFOT) have been kept on throughout ICU stay in 50 (55%) patients, while 41 (45%) patients were put on IMV. Overall ICU mortality was 41%, while ICU mortality of patients on NIV was 14%.

CONCLUSIONS

High PEEP NIV was convenient and safe as initial respiratory support and in some COVID-19 ARDS patients remained an optimal respiratory support throughout their disease.

Neurally Adjusted Ventilatory Assist in Acute Respiratory Failure-A Narrative Review

Maintaining spontaneous breathing has both potentially beneficial and deleterious consequences in patients with acute respiratory failure, depending on the balance that can be obtained between the protecting and damaging effects on the lungs and the diaphragm. Neurally adjusted ventilatory assist (NAVA) is an assist mode, which supplies the respiratory system with a pressure proportional to the integral of the electrical activity of the diaphragm. This proportional mode of ventilation has the theoretical potential to deliver lung- and respiratory-muscle-protective ventilation by preserving the physiologic defense mechanisms against both lung overdistention and ventilator overassistance, as well as reducing the incidence of diaphragm disuse atrophy while maintaining patient–ventilator synchrony. This narrative review presents an overview of NAVA technology, its basic principles, the different methods to set the assist level and the findings of experimental and clinical studies which focused on lung and diaphragm protection, machine–patient interaction and preservation of breathing pattern variability. A summary of the findings of the available clinical trials which investigate the use of NAVA in acute respiratory failure will also be presented and discussed.

Molecular Mechanisms and Physiological Changes behind Benign Tracheal and Subglottic Stenosis in Adults

Laryngotracheal stenosis (LTS) is a complex and heterogeneous disease whose pathogenesis remains unclear. LTS is considered to be the result of aberrant wound-healing process that leads to fibrotic scarring, originating from different aetiology. Although iatrogenic aetiology is the main cause of subglottic or tracheal stenosis, also autoimmune and infectious diseases may be involved in causing LTS. Furthermore, fibrotic obstruction in the anatomic region under the glottis can also be diagnosed without apparent aetiology after a comprehensive workup; in this case, the pathological process is called idiopathic subglottic stenosis (iSGS). So far, the laryngotracheal scar resulting from airway injury due to different diseases was considered as inert tissue requiring surgical removal to restore airway patency. However, this assumption has recently been revised by regarding the tracheal scarring process as a fibroinflammatory event due to immunological alteration, similar to other fibrotic diseases. Recent acquisitions suggest that different factors, such as growth factors, cytokines, altered fibroblast function and genetic susceptibility, can all interact in a complex way leading to aberrant and fibrotic wound healing after an insult that acts as a trigger. However, also physiological derangement due to LTS could play a role in promoting dysregulated response to laryngo-tracheal mucosal injury, through biomechanical stress and mechanotransduction activation. The aim of this narrative review is to present the state-of-the-art knowledge regarding molecular mechanisms, as well as mechanical and physio-pathological features behind LTS.

Noninvasive respiratory support for acute respiratory failure due to COVID-19

PURPOSE OF REVIEW

Noninvasive respiratory support has been widely applied during the COVID-19 pandemic. We provide a narrative review on the benefits and possible harms of noninvasive respiratory support for COVID-19 respiratory failure.

RECENT FINDINGS

Maintenance of spontaneous breathing by means of noninvasive respiratory support in hypoxemic patients with vigorous spontaneous effort carries the risk of patient self-induced lung injury: the benefit of averting intubation in successful patients should be balanced with the harms of a worse outcome in patients who are intubated after failing a trial of noninvasive support.The risk of noninvasive treatment failure is greater in patients with the most severe oxygenation impairment (PaO2/FiO2 < 200 mmHg).High-flow nasal oxygen (HFNO) is the most widely applied intervention in COVID-19 patients with hypoxemic respiratory failure. Also, noninvasive ventilation (NIV) and continuous positive airway pressure delivered with different interfaces have been used with variable success rates. A single randomized trial showed lower need for intubation in patients receiving helmet NIV with specific settings, compared to HFNO alone.Prone positioning is recommended for moderate-to-severe acute respiratory distress syndrome patients on invasive ventilation. Awake prone position has been frequently applied in COVID-19 patients: one randomized trial showed improved oxygenation and lower intubation rate in patients receiving 6-h sessions of awake prone positioning, as compared to conventional management.

SUMMARY

Noninvasive respiratory support and awake prone position are tools possibly capable of averting endotracheal intubation in COVID-19 patients; carefully monitoring during any treatment is warranted to avoid delays in endotracheal intubation, especially in patients with PaO2/FiO2 < 200 mmHg.

[Recurrent Pulmonary Hemorrhages with Hemoptysis as a Result of Vocal Cord Dysfunction (VCD) - An Attempt to Explain]

We present the case of an otherwise healthy 19-year-old student who has been affected by vocal cord dysfuntion (VCD) since she is fourteen. 3 years after that diagnosis she has also been coughing blood at an increasing rate (1-3 times per week). We postulate that the haemoptoe is the result of breathing against a closed airway which can lead to excessively high negative intrathoracic pressures. Which, in turn, rapture alveolar capillaries. After bilateral injection of Botulinum toxin injection into the muscles vocalis, VCD as well as haemoptoe episodes ceased for three months.

High parasternal intercostal muscle thickening prior to intubation in COVID-19 infection

Acute hypoxemic respiratory failure (AHRF) is a major complication of COVID-19 pneumonia and parasternal intercostal muscle thickening may be used as a biomarker to assess inspiratory effort. We report the case of a high utilization of parasternal intercostal muscle prior to the introduction of invasive ventilation in a 66-year old male none vaccinated COVID -19 patient admitted in hospital because of AHRF.

Foreign body aspirations in dental clinics: a narrative review

Foreign body aspiration can produce a medical emergency. Obstruction of the airways can be life-threatening, and complications may develop in less-severe cases if it is left untreated. Although it is more prevalent in children by approximately three times, adults can still experience it, and it is more frequently related to healthcare in adults. Objects used in dental treatment are usually placed in the oral cavity and can be ingested or inhaled by accident. Dental treatment has been identified as an important cause of the misplacement of foreign bodies in the airway. However, few reports have been published on dentistry-related foreign body aspiration. This paper discusses the disease course, management, and clinical outcomes of foreign body aspiration, especially those associated with dentistry. The patient must be examined for respiratory distress. If the patient is unstable, urgent airway management and the maneuvers for removal should be performed. Radiographs and computed tomography can help identify and locate the object. The treatment of choice is often bronchoscopy, and both flexible and rigid endoscopes can be used depending on the situation. Preventive measures need to be implemented to avoid inhalation accidents given the potential consequences. Though the incidence is rare, healthcare levels need to be enhanced to avert morbidity and mortality. Radiological evaluation and bronchoscopy are vital for management.

Retrospective evaluation of negative-pressure pulmonary edema in dogs (2006-2018): 35 cases

OBJECTIVE

To describe the clinical characteristics and outcomes in a population of dogs with negative-pressure pulmonary edema (NPPE) and to identify the main causes of the disease. To evaluate any associations with morbidity and mortality.

DESIGN

Retrospective study.

SETTING

Three university teaching hospitals and 2 private referral centers in the United Kingdom.

ANIMALS

Thirty-five client-owned dogs presented with NPPE.

INTERVENTIONS

None MEASUREMENTS AND MAIN RESULTS: Data collected included patient characteristics, clinical history, clinicopathological abnormalities, radiographic features, treatments, and outcomes. The median age was 4 months (range 2-90) and median weight was 7.1 kg (range 1.7-37.2). There were many causes of NPPE including leash tugs, near hanging, accidental choking, anatomical obstruction to airflow, and purposeful airway obstruction by people. The most common cause of NPPE was accidental choking (40% of cases). Dogs with an anatomical obstruction were older than 24 months. Hypoxemia with an increased alveolar-arterial gradient was common on presentation. The majority of thoracic radiographs (65.7%) showed an alveolar or interstitial pattern in the caudodorsal area as previously described in the literature. Oxygen therapy was administered to 33 (94.3%) dogs. Furosemide was administered to 18 (51.4%) dogs. The median length of hospitalization was 2 days (range 0-14). Twenty-eight (80%) dogs survived to discharge. Seven dogs were mechanically ventilated and only 2 of them (28.6%) survived to discharge. The requirement for mechanical ventilation was the only parameter associated with mortality (P < 0.001).

CONCLUSIONS

Most cases of NPPE occur in juvenile dogs. Different incidents associated with upper airway obstruction can produce an episode of NPPE. Choking on food or toys and near hanging have not been previously described in the veterinary literature as inciting causes of NPPE. The overall prognosis is good.

Predictors of post-extubation stridor in patients on mechanical ventilation: a prospective observational study

The cuff leak test (CLT) has been widely accepted as a simple and noninvasive method for predicting post-extubation stridor (PES). However, its accuracy and clinical impact remain uncertain. We aimed to evaluate the reliability of CLT and to assess the impact of pre-extubation variables on the incidence of PES. A prospective observational study was performed on adult critically ill patients who required mechanical ventilation for more than 24 h. Patients were extubated after the successful spontaneous breathing trial, and CLT was conducted before extubation. Of the 191 patients studied, 26 (13.6%) were deemed positive through CLT. PES developed in 19 patients (9.9%) and resulted in a higher reintubation rate (8.1% vs. 52.6%, p < 0.001) and longer intensive care unit stay (8 [4.5-14] vs. 12 [8-30.5] days, p = 0.01) than patients without PES. The incidence of PES and post-extubation outcomes were similar in patients with both positive and negative CLT results. Compared with patients without PES, patients with PES had longer durations of endotracheal intubation and required endotracheal suctioning more frequently during the 24-h period prior to extubation. After adjusting for confounding factors, frequent endotracheal suctioning more than 15 times per day was associated with an adjusted odds ratio of 2.97 (95% confidence interval, 1.01-8.77) for PES. In conclusion, frequent endotracheal suctioning before extubation was a significant PES predictor in critically ill patients. Further investigations of its impact on the incidence of PES and patient outcomes are warranted.

A rare case of type II negative pressure pulmonary edema following extraction of inhaled peanuts in a 21-month-old boy

To date, only one case of pediatric type II negative pressure pulmonary edema (NPPE) caused by removal of an endobronchial foreign body has been documented. We report another case of type II NPPE that developed after extraction of inhaled peanuts. A 21-month-old boy who presented with wheezing and intermittent cough for 1 month after eating peanuts was admitted to our department. A chest computed tomographic scan showed foreign bodies lodged in the right main bronchus. Fiberoptic bronchoscopy was performed, and three pieces of peanuts were removed. Fifteen minutes after this procedure, the child grew restless and started coughing with frothy pink sputum. Tachypnea and rales were observed. A chest radiograph showed patchy opacification in both lungs, especially in the right lower zone, leading to the diagnosis of type II NPPE. Intravenous furosemide and dexamethasone were immediately administered, followed by non-invasive continuous positive airway pressure ventilation. Twelve hours later, the patient recovered uneventfully and was discharged home the following day. In conclusion, pediatric type II NPPE rapidly occurs following the relief of upper airway obstruction. Clinicians need to be aware of the acuteness and manifestations of type II NPPE to make an early diagnosis and initiate prompt treatment.