Aspiration-related lung diseases. J Thorac Imaging. 2014;29:304-309. [PMID: 24911122 DOI: 10.1097/rti.0000000000000092]

Pulmonary Aspiration Syndromes: An Imaging-based Review

The term "aspiration" describes lung injury that results from unintentional passage of contents other than air into the lungs and bronchial tree, commonly from the gastrointestinal and upper respiratory tracts. Only a small proportion of aspiration-related events are symptomatic, especially in predisposed individuals such as patients with diminished consciousness, impaired swallowing, oesophageal motility disorders, and reflux disease. Aspiration-related syndromes can be classified based on the onset of presentation, composition of the aspirated substance, and anatomic site of injury. When considering the injury site, the aspirated material can either obstruct the airways, thereby presenting with obstructive features (eg, atelectasis on radiographs); it can alternatively affect the lung parenchyma. Lung injury due to aspiration of noxious agents such as acid or lipids is termed chemical aspiration pneumonitis. The aspirated contents can alternatively lead to lung parenchymal infection when the contents are infected, which is termed aspiration pneumonia. We have reviewed the imaging manifestations of various entities related to aspiration and have classified the abnormalities based on the site of injury and the nature of the culprit agent. Differences between "aspiration pneumonitis" and "aspiration pneumonia" are also explored. This is followed by an illustration of a few specific situations related to aspiration in pediatric and adult patients.

Imaging of Aspiration: When to Suspect Based on Imaging of Bacterial Aspiration, Chemical Aspiration, and Foreign Body Aspiration

Aspiration-related syndromes comprise a broad spectrum of diseases affecting the airways and lung parenchyma resulting from inadvertent entry of oropharyngeal or gastric contents into the respiratory tract. The diagnosis can be challenging given lack of self-reported symptoms and unwitnessed or silent aspiration events. Aspiration is a common finding in healthy individuals suggesting that host defenses play a critical role in the pathophysiology. In the absence of strict criterion, a high index of suspicion is necessary based on recognition of established risk factors and identification of characteristic imaging findings. Conditions predisposing to altered levels of consciousness and neuromuscular weakness can lead to dysphagia, impaired cough reflux, and subsequent aspiration. The most salient feature on imaging is the anatomic location of the abnormalities, with the superior segments of the lower lobes and posterior segments of upper lobes involved in the recumbent position, and basilar segments of lower lobes in the upright position. Acute syndromes include pneumonia, pneumonitis, and foreign body aspiration. In the more indolent form of aspiration, bronchiectasis, diffuse bronchiolitis, and interstitial lung disease can develop. A detailed understanding of associated radiographic findings for these syndromes can help to implicate aspiration as the cause for imaging abnormalities and ultimately optimize patient management.

Impaired oral health: a required companion of bacterial aspiration pneumonia

Laryngotracheal aspiration has a widely-held reputation as a primary cause of lower respiratory infections, such as pneumonia, and is a major concern of care providers of the seriously ill orelderly frail patient. Laryngeal mechanical inefficiency resulting in aspiration into the lower respiratory tract, by itself, is not the cause of pneumonia. It is but one of several factors that must be present simultaneously for pneumonia to develop. Aspiration of oral and gastric contentsoccurs often in healthy people of all ages and without significant pulmonary consequences. Inthe seriously ill or elderly frail patient, higher concentrations of pathogens in the contents of theaspirate are the primary catalyst for pulmonary infection development if in an immunocompromised lower respiratory system. The oral cavity is a complex and ever changing eco-environment striving to maintain homogeneity among the numerous microbial communities inhabiting its surfaces. Poor maintenance of these surfaces to prevent infection can result inpathogenic changes to these microbial communities and, with subsequent proliferation, can altermicrobial communities in the tracheal and bronchial passages. Higher bacterial pathogen concentrations mixing with oral secretions, or with foods, when aspirated into an immunecompromised lower respiratory complex, may result in bacterial aspiration pneumonia development, or other respiratory or systemic diseases. A large volume of clinical evidence makes it clear that oral cleaning regimens, when used in caring for ill or frail patients in hospitals and long-term care facilities, drastically reduce the incidence of respiratory infection and death. The purpose of this narrative review is to examine oral health as a required causative companionin bacterial aspiration pneumonia development, and the effectiveness of oral infection control inthe prevention of this disease.

Asymptomatic Dysphagia and Aspiration in Patients with Idiopathic Bronchiectasis

PURPOSE

Although considered contributors to idiopathic bronchiectasis (IB), neither dysphagia nor silent aspiration have been systematically evaluated in IB patients. We aimed to explore the prevalence of asymptomatic dysphagia and silent aspiration in IB patients and to identify parameters predictive of their presence.

METHODS

This prospective cohort study included IB patients from our Pulmonary Institute without prior history of dysphagia and without prior dysphagia workup. Swallowing function was assessed by the Eating Assessment Tool (EAT-10) questionnaire and by the Fiberoptic Endoscopic Evaluation of Swallowing (FEES) test.

RESULTS

Forty-seven patients (31 females, mean age 67 ± 16 years) were recruited. An EAT-10 score ≥ 3 (risk for swallowing problems) was present in 21 patients (44.6%). Forty-two patients (89.3%) had at least one abnormal swallowing parameter in the FEES test. Six patients (12.7%) had a penetration aspiration score (PAS) in the FEES of at least 6, indicating aspiration. An EAT-10 score of 3 was found to be the ideal cutoff to predict aspiration in the FEES, with a good level of accuracy (area under the curve = 0.78, 95% CI 0.629-0.932, p = 0.03) and sensitivity of 83%. This cutoff also showed a trend towards a more severe disease using the FACED (forced expiratory volume, age, colonization with pseudomonas, extension of lung involvement, dyspnea) score (p = 0.05).

CONCLUSION

Dysphagia is prevalent in IB and may be undiagnosed if not specifically sought. We recommend screening all patients with IB for dysphagia by the EAT-10 questionnaire and referring all those with a score of ≥ 3 to formal swallowing assessment.

Effectiveness of Drip Infusion of Lascufloxacin, a Novel Fluoroquinolone Antibiotic, for Patients with Pneumonia Including Chronic Lung Disease Exacerbations and Lung Abscesses

Background

Lascufloxacin (LSFX), a novel fluoroquinolone antibacterial agent, has recently been used as a drip infusion for treating pneumonia, apparently with good effectiveness against various bacteria, including anaerobes, and good intrapulmonary penetration.

Methods

The clinical effectiveness of LSFX was retrospectively investigated for the 55 patients admitted to our hospital with pneumonia, including chronic lung disease exacerbations and lung abscesses, from May 2021 to July 2023.

Results

The median age of the 55 patients was 76.1 (34.1-93.1) years, 45 (81.8%) were male, and 48 (87.5%) patients had underlying disease. Community-acquired pneumonia was seen in 47 (85.5%) patients, including 9 (16.4%) with lung abscess, and the other 8 (14.5%) had nursing and healthcare-associated pneumonia/hospital-acquired pneumonia. Moderate pneumonia was present in 33 (61.8%) of 55 patients, and LSFX was used as a second-line treatment for 28 (50.9%) patients in whom first-line antibiotics were ineffective. The median duration of intravenous LSFX administration was 9 (2.0-49) days. Streptococcus pneumoniae and methicillin-susceptible Staphylococcus aureus were isolated from 3 (7.1%) and 2 (4.8%) patients, respectively. Of the 55 patients, 45 (81.5%) improved clinically with intravenous LSFX administration; 20 (95.2%) of 21 community-acquired pneumonia cases, including 9 (100.0%) of 9 bacterial pneumonia cases, were improved by LSFX as first-line treatment, and 8 (88.9%) of 9 lung abscess patients also showed clinical improvement with LSFX as a second-line treatment. There were no severe adverse effects in any of the 55 patients.

Conclusion

Based on these data, intravenous administration of LSFX seems effective for bacterial pneumonia, including chronic lung disease exacerbations and lung abscesses, and it appears to have broad antimicrobial activity and good tissue penetration into the lung.

Inhalation Pneumonitis Caused by Nebulized Hydrogen Peroxide

Hydrogen peroxide is a chemical commonly used as a household antiseptic for cleaning and disinfecting. No cases of acute hydrogen peroxide inhalation-induced lung injury are previously described. We present a case of acute chemical pneumonitis caused by mixing hydrogen peroxide in a nighttime continuous positive airway pressure device's humidifier used for obstructive sleep apnea to prevent COVID-19 infection. The patient endorsed mixing hydrogen peroxide with distilled water in his nighttime continuous positive airway pressure device's humidifier at a ratio of 1:3-1:2 for the previous week before admission based on a friend's advice in preventing COVID-19. The presenting chest X-ray showed new multifocal consolidations with interstitial markings and alveolar edema throughout both lungs. Chest computed tomography (CT) imaging demonstrated multifocal, bilateral, hazy consolidations with increased interstitial markings and bilateral pleural effusions. The patient was subsequently initiated on systemic glucocorticoid therapy, significantly improving hypoxemia and dyspnea. Inhalation of hydrogen peroxide may produce acute pneumonitis distinct from what has been described previously with chronic inhalation. Given this case, systemic glucocorticoid therapy may be considered a viable treatment option for acute hydrogen peroxide-associated inhalation lung injury causing pneumonitis.

Schematic approach to the diagnosis of multifocal lung opacities in the emergency department

Radiologists in the emergency department must be prepared to deal with any type of disease in any organ at any time. Many entities involving the chest can result in patients' presenting at the emergency department. This chapter deals with entities that manifest with multifocal lung opacities and that can be mistaken for pneumonia. To facilitate their identification, this chapter approaches these entities by considering their most characteristic distribution on chest X-rays, the main diagnostic modality used for thoracic problems in the emergency department. Our schematic approach includes the key findings in patients' personal histories, clinical examination, laboratory tests, and imaging studies that can be available during the initial workup.

Development and implementation of an aspiration pneumonia cause investigation algorithm

The diagnostic criteria of aspiration pneumonia have not been established, and it remains an underdiagnosed entity. Diagnosis and cause investigation is essential in improving the management of aspiration pneumonia. The Japanese Respiratory Society Guidelines for the Management of Pneumonia in Adults (JRS Guidelines) show a list of risk factors for aspiration pneumonia. We developed an algorithm to aid physicians in evaluating these possible underlying factors and guide their management with a focus on aspiration pneumonia. The algorithm was developed based on the JRS Guidelines. The algorithm suggested dysphagia screening, pneumococcal and influenza vaccination, and other preventative measures for pneumonia. The algorithm was implemented in the acute setting of a general hospital among older patients admitted with pneumonia. Their outcomes were compared with a historical control group constituting similar patients from the previous year. Forty patients with pneumonia were assessed with the algorithm group, and 44 patients were included in the control group. In the algorithm group, significantly more cases (95.0% vs. 15.9%, p < 0.01) underwent early screening for a swallowing disorder. Two patients in the algorithm group were diagnosed with a new condition causing aspiration pneumonia, as opposed to none in the control group. Drugs with a potential risk for aspiration were identified and discontinued in 27.5% of the patients in the algorithm group and 4.5% in the control group. In conclusion, an aspiration pneumonia cause investigation algorithm translating the JRS guideline approach into practice enhanced the rate of swallow screening and preventative measures for aspiration.

Use of PDSA Cycles to Increase Aspiration Risk and Swallow Screening Documentation in the Hospitalized General Medical Patient Care Population

BACKGROUND

Aspiration, while hospitalized, can lead to increases in length of stay and health care costs. Nurses must identify patients at risk of aspiration early to initiate appropriate precautions.

LOCAL PROBLEM

An increase in-hospital patient aspirations at a Midwestern hospital prompted a review of events, which identified opportunities to improve identification of patients' risk factors and completion of the bedside swallow screening.

METHODS

Interventions were identified via a causal factor tree analysis and an impact-effort grid then deployed using the Plan-Do-Study-Act (PDSA) methodology.

INTERVENTIONS

Interventions deployed included game based-learning, a unit-based champion, and the use of visual cues to identify patients at risk for aspiration.

RESULTS

After 3 PDSA cycles, documentation of patients' aspiration risk factors on admission increased by 40%, with a 51.3% increase in bedside swallow screening results.

CONCLUSION

Iterative PDSA cycles successfully tested staff engagement strategies to improve aspiration risk and swallow screening documentation compliance.

Computed tomographic findings in dogs with suspected aspiration pneumonia: 38 cases (2014‐2019)

OBJECTIVES

To describe computed tomographic (CT) findings in dogs diagnosed with aspiration pneumonia and to assess for any correlation with patient outcome.

MATERIALS AND METHODS

Retrospective analysis of 38 cases with a presumptive diagnosis of aspiration pneumonia at two UK referral centres. Medical records were reviewed for signalment, history, physical examination and clinicopathologic data. CT examinations of the thorax were reviewed by the European College of Veterinary Diagnostic Imaging board-certified radiologist for all dogs to describe the characteristics and distribution of the pulmonary lesions.

RESULTS

The most common CT findings were lung lobe consolidation associated with air bronchograms (100%) followed by ground-glass attenuation (89.4%), bronchial wall thickening (36.8%), bronchiolectasis (31.5%) and bronchiectasis (15.7%). Large-breed dogs were overrepresented. Duration of hospitalisation ranged between 0 and 8 days (mean 3 days). Overall, 89.4% of dogs survived the aspiration event and were discharged from the hospital. The four dogs that did not survive to discharge had five or more lobes affected on CT.

CLINICAL SIGNIFICANCE

CT findings in dogs with aspiration pneumonia are described. CT is a useful imaging modality to diagnose aspiration pneumonia.

Bacterial infection in dogs with aspiration pneumonia at 2 tertiary referral practices

Background

In dogs, antimicrobial drugs are widely prescribed for aspiration pneumonia (AP) despite poor documentation of bacterial infection in AP (b‐AP) using bronchoalveolar lavage fluid (BALF) analysis. Interpretating discordant cytology and culture results is challenging, contributing to lack of a criterion standard, and highlighting differences between veterinary and human medical criteria for b‐AP.

Objectives

Determine how many dogs with AP had BALF collection and differences in diagnosis of b‐AP using veterinary vs human medical criteria. Report findings of noninvasive markers (e.g. fever, band neutrophilia, radiographic severity score) in dogs with and without b‐AP.

Animals

Retrospective cohort study of client‐owned dogs (n = 429) with AP at 2 university veterinary hospitals. Twenty‐four dogs met enrollment criteria.

Methods

Inclusion criteria were radiographic diagnosis of AP, ≥1 risk factor, CBC findings, and BALF cytology and culture results. Veterinary medical b‐AP criteria were cytology findings compatible with sepsis with or without positive culture, or cytology findings not consistent with sepsis and positive culture (≥1.7 × 10³ cfu/mL). Human medical b‐AP criteria required culture with ≥10⁴ cfu/mL or > 7% cells with intracellular bacteria on cytology.

Results

Only 24/429 dogs met all enrollment criteria; 379/429 dogs lacked BALF collection. Diagnosis of b‐AP differed using veterinary (79%) vs human (29%) medical criteria. Fever, band neutrophils and high radiographic scores were noted in dogs with and without b‐AP.

Conclusions and Clinical Importance

Lack of routine BALF collection hampers definitive recognition of bacterial infection in AP. Differences in dogs meeting veterinary vs human medical definitions for b‐AP and usefulness of noninvasive markers warrant further study to improve understanding of the role of bacteria in AP.

Aspiration Is Associated with Poor Treatment Response in Pediatric Pulmonary Vein Stenosis

Intraluminal pulmonary vein stenosis is a disease with significant morbidity and mortality, though recent progress has been made using multimodal therapy with antiproliferative agents. The aim of this study was to evaluate the association between aspiration and poor treatment response in patients with intraluminal pulmonary vein stenosis. A retrospective, single-center cohort analysis was performed of patients treated with a combination of imatinib mesylate and multimodal anatomic relief between March 2009 and November 2019. Analysis focused on 2-ventricle patients due to small numbers and clinical heterogeneity of single ventricle patients. Among the 84 patients included, 15 had single ventricle physiology and 69 had 2-ventricle physiology. Among the 2-ventricle group, multivariable analysis revealed that patients with clinical aspiration had nearly five times higher odds of poor treatment response than patients without aspiration (OR 4.85, 95% CI [1.37, 17.2], p = 0.014). Furthermore, male patients had higher odds of poor treatment response than their female counterparts (OR 3.67, 95% CI [1.04, 12.9], p = 0.043). Aspiration is a novel, potentially modifiable risk factor for poor treatment response in pediatric multi-vessel intraluminal pulmonary vein stenosis in patients with 2-ventricle physiology.

Non-Infectious Granulomatous Lung Disease: Imaging Findings with Pathologic Correlation

Non-infectious granulomatous lung disease represents a diverse group of disorders characterized by pulmonary opacities associated with granulomatous inflammation, a relatively nonspecific finding commonly encountered by pathologists. Some lesions may present a diagnostic challenge because of nonspecific imaging features; however, recognition of the various imaging manifestations of these disorders in conjunction with patients' clinical history, such as age, symptom onset and duration, immune status, and presence of asthma or cutaneous lesions, is imperative for narrowing the differential diagnosis and determining appropriate management of this rare group of disorders. In this pictorial review, we describe the pathologic findings of various non-infectious granulomatous lung diseases as well as the radiologic features and high-resolution computed tomography imaging features.

A Case of Aspiration Pneumonia Caused by Cerebrospinal Fluid Leaks Associated with Delayed Identification of Iatrogenic Skull Base Injury during Endoscopic Sinus Surgery

Cerebrospinal fluid (CSF) leaks associated with endoscopic sinus surgery (ESS) are a rare complication affecting approximately 0.09% of patients. Although meningitis is a well-known complication of CSF leaks, the case we present is a rare and cautionary case of CSF leakage associated with ESS leading to aspiration pneumonia. A 43-year-old man with CSF leaks after ESS was referred to our hospital. After the operation, sometimes, he reported having a serous nasal discharge from the right side when he bent over, and he woke up choking on something every day. He also experienced headache, fever, fatigue, and cough. Interestingly, chest computed tomography (CT) showed a consolidation and ground-glass opacity in the posterior segments of the right upper lobes and superior segments of the bilateral lower lobes. These CT imaging findings were similar to those of aspiration pneumonia in bedridden patients who are always in a supine position. These findings suggest that CSF caused aspiration pneumonia. To the best of our knowledge, no case of aspiration pneumonia caused by CSF during endoscopic sinus surgery has been reported until now. If a patient with CSF leakage after ESS experiences fever, cough, or fatigue, physicians should consider aspiration pneumonia in addition to meningitis.

[Intraoperative Aspiration]

术中误吸是外科手术中常见的肺部并发症，麻醉和体位是导致术中误吸的主要因素。近年来，围手术期肺保护已受到外科和麻醉医师的广泛关注，如何加速术后康复进程，减少相关并发症发生，显著改善患者预后已成为当前外科治疗的主要目标。本文将以术中误吸为重点，从解剖、病理生理、表现、诊断、处理和预防等方面展开综述。

Evaluation of the therapeutic effect of high-flow nasal cannula oxygen therapy on patients with aspiration pneumonia accompanied by respiratory failure in the post-stroke sequelae stage

Background

The aim of the present study was to evaluate the therapeutic effect of high-flow nasal cannula (HFNC) oxygen therapy on patients with aspiration pneumonia accompanied by respiratory failure in the post-stroke sequelae stage, with the goal of providing more effective oxygen therapy and improving patient prognosis.

Methods

Retrospective analysis was conducted on 103 elderly patients with post-stroke aspiration pneumonia and moderate respiratory failure (oxygenation index: 100–200 mmHg) that had been admitted. The patients were divided into two groups according to the mode of oxygen therapy that was used: the Venturi mask group and the HFNC treatment group. The two groups were analyzed and compared in terms of the changes in the blood gas indices measured at different points in time (4, 8, 12, 24, 48, and 72 h), the proportion of patients that required transition to invasive auxiliary ventilation, and the 28-day mortality rate.

Results

A total of 103 patients were retrospectively analyzed; 16 cases were excluded, and 87 patients were included in the final patient group (42 in the HFNC group and 45 in the Venturi group). There was a statistically significant difference in the oxygenation indices of the HFNC group and the Venturi group (F = 546.811, P < 0.05). There was a statistically significant interaction between the monitored oxygenation indices and the mode of oxygen therapy (F = 70.961, P < 0.05), and there was a statistically significant difference in the oxygenation indices for the two modes of oxygen therapy (F = 256.977, P < 0.05). HFNC therapy contributed to the improvement of the oxygenation indices at a rate of 75.1%. The Venturi and HFNC groups also differed significantly in terms of the proportion of patients that required transition to invasive auxiliary ventilation within 72 h (P < 0.05). The HFNC group’s risk for invasive ventilation was 0.406 times that of the Venturi group (P < 0.05). There was no statistical difference in the 28-day mortality rate of the two groups (P > 0.05).

Conclusion

HFNC could significantly improve the oxygenation state of patients with post-stroke aspiration pneumonia and respiratory failure, and it may reduce the incidence of invasive ventilation.

Investigation of high-resolution computed tomographic (HRCT) outcomes associated with chronic pulmonary microaspiration (CPM) in Tehran and Zahedan, Iran

Background

In patients with chronic pulmonary microaspiration (CPM) the recognition of high-resolution computed tomographic (HRCT) findings and their pattern is important.

Objective

To investigate the HRCT detections in patients with CPM.

Materials and Methods

This descriptive study enrolled 100 consecutive patients with CPM underwent HRCT of the lungs between 2017 and 2018 in Tehran and Zahedan Hospitals and private centers. The required variables were recorded for each patient with a questionnaire. Subsequently, HRCT was performed and abnormalities were then reported by two radiologists.

Results

Most of patients exhibited bronchial thickening in 33.6% of cases, followed by ground-glass opacity (12.4%), emphysema (11.1%), and bronchiectasis (8.5%). In addition, the most common HRCT findings were found in left lower lobe (LLL) (37.1%), followed by right lower lobe (RLL) (35.9 %), right upper lobe (RUL) (6,2%), and left upper lobe (LUL) (6%).

Conclusion

Our data showed the most common findings in HRCT were bronchial thickening ground-glass opacity, emphysema, and bronchiectasis, where these findings was dominantly found in LLL, RLL, RUL, and LUL, indicating its high tendency to dependent areas.

Aerodigestive Disease in Dogs

Aerodigestive disorders (AeroDs) in people encompass a wide range of clinical syndromes, reflecting the complex relationship between the respiratory and digestive tracts. In veterinary medicine, aspiration is used interchangeably with aspiration pneumonia. Although aspiration pneumonia is a common disorder in dogs, it does not reflect the breadth of AeroDs. Unfortunately, AeroDs rarely are investigated in veterinary medicine because of lack of clinical recognition, limitations in available diagnostics, and the fact that AeroDs may be caused by occult digestive disease. Recognizing patients with AerodD represents an area of significant clinical importance that may provide additional areas of clinical intervention.

Multimodality imaging of COVID-19 pneumonia: from diagnosis to follow-up. A comprehensive review

Due to its pandemic diffusion, SARS- CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) infection represents a global threat. Despite a multiorgan involvement has been described, pneumonia is the most common manifestation of COVID-19 (Coronavirus disease 2019) and it is associated with a high morbidity and a considerable mortality. Especially in the areas with high disease burden, chest imaging plays a crucial role to speed up the diagnostic process and to aid the patient management. The purpose of this comprehensive review is to understand the diagnostic capabilities and limitations of chest X-ray (CXR) and high-resolution computed tomography (HRCT) in defining the common imaging features of COVID-19 pneumonia and correlating them with the underlying pathogenic mechanisms. The evolution of lung abnormalities over time, the uncommon findings, the possible complications, and the main differential diagnosis occurring in the pandemic phase of SARS-CoV-2 infection are also discussed.

Effect of Oral Glucose Water Administration 1 Hour Preoperatively in Children with Cyanotic Congenital Heart Disease: A Randomized Controlled Trial

Background

Guidelines recommend a clear liquid fasting time of 2 h before surgery, which is often exceeded, leading to adverse reactions (ARs) such as discomfort, thirst, and dehydration. We assessed the gastric contents and ARs after oral glucose water administration 1 h prior to surgery in children with cyanotic congenital heart disease (CCHD).

Material/Methods

This was a non-inferiority randomized controlled trial of children with CCHD enrolled at the Fujian Medical University Union Hospital from 09/2014 to 05/2017 and randomized to receive oral glucose water (10 g of glucose in 100 ml of warm water, 5 ml/kg) 2 h (2-h group, n=174) or 1 h (1-h group, n=170) before surgery. The primary endpoint was gastric volume. Secondary endpoints included pH of gastric content, preoperative blood glucose, and risk factors for aspiration pneumonia. Pre- and intraoperative ARs were recorded.

Results

The 1-h group showed smaller gastric content volumes (0.34±0.35 (95% CI: 0.29–0.39) vs. 0.43±0.33 (95% CI: 0.38–0.48) ml/kg, t=2.55, P<0.05) and higher blood glucose (6.21±0.78 (95% CI: 6.09–6.33) vs. 5.59±1.11 (95% CI: 5.43–5.76) mmol/L, t=−5.91, P<0.001). The 95% confidence interval of the volume difference between the 2 groups was 0.017–0.163, the upper limit value was 0.163 <δ=0.2 (P<0.01). The non-inferiority hypothesis was correct. The 1-h group showed lower incidence of crying, thirst and hypoxia (all P<0.05 vs. 2-h group). There were no differences in ARs between the 2 groups.

Conclusions

A 1-h fast prior to surgery was not inferior to a 2-h fast in terms of gastric residuals and ARs in pediatric patients with CCHD.

Clinical trial registration: http://www.chictr.org.cn/showprojen.aspx?proj=9563

Registration number: ChiCTR-IPR-14005270

Recent advances in the understanding of bronchiolitis in adults

Bronchiolitis is injury to the bronchioles (small airways with a diameter of 2 mm or less) resulting in inflammation and/or fibrosis. Bronchioles can be involved in pathologic processes that involve predominantly the lung parenchyma or large airways, but, in some diseases, bronchioles are the main site of injury ("primary bronchiolitis"). Acute bronchiolitis caused by viruses is responsible for most cases of bronchiolitis in infants and children. In adults, however, there is a wide spectrum of bronchiolar disorders and most are chronic. Many forms of bronchiolitis have been described in the literature, and the terminology in this regard remains confusing. In clinical practice, a classification scheme based on the underlying histopathologic pattern (correlates with presenting radiologic abnormalities) facilitates the recognition of bronchiolitis and the search for the inciting cause of the lung injury. Respiratory bronchiolitis is the most common form of bronchiolitis in adults and is usually related to cigarette smoking. Currently, the diagnosis of respiratory bronchiolitis is generally achieved based on the clinical context (smoking history) and chest CT findings. Constrictive (obliterative) bronchiolitis is associated with airflow obstruction and is seen in various clinical contexts including environmental/occupational inhalation exposures, transplant recipients (bronchiolitis obliterans syndrome), and many others. Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is increasingly recognized and can be associated with progressive airflow obstruction related to constrictive bronchiolitis ("DIPNECH syndrome"). Diffuse aspiration bronchiolitis is a form of aspiration-related lung disease that is often unsuspected and confused for interstitial lung disease. Novel forms of bronchiolitis have been described, including lymphocytic bronchiolitis and alveolar ductitis with emphysema recently described in employees at a manufacturing facility for industrial machines. Bronchiolitis is also a component of vaping-related lung injury encountered in the recent outbreak.

Update on Rare Idiopathic Interstitial Pneumonias and Rare Histologic Patterns

CONTEXT

- In 2013, the revised American Thoracic Society and European Respiratory Society classification of idiopathic interstitial pneumonias (IIPs) described 2 rare IIPs and 2 rare histologic patterns. Because of the rarity of the disease, there is limited evidence related to the histology. Because the rare histologic patterns are provisional criteria, no unanimous consensus on histologic diagnostic criteria has yet been reached.

OBJECTIVE

- To review the histologic features for rare IIPs and rare histologic patterns, and to provide diagnostic aids and discuss the differential diagnosis.

DATA SOURCES

- Published peer-reviewed literature and the authors' personal experience.

CONCLUSIONS

- Following the publication of the international consensus classification, evidence regarding rare IIPs and rare histologic patterns has accumulated to some extent, although to date the amount remains insufficient and further evidence is required. Because the diagnosis is sometimes challenging, a multidisciplinary approach represents the gold standard in reaching an accurate diagnosis for these rare disorders.

Chronic Airspace Diseases

Airspace disease can be acute or chronic and commonly present as consolidation or ground-glass opacity on chest imaging. Consolidation or ground-glass opacity occurs when alveolar air is replaced by fluid, pus, blood, cells, or other material. Airspace disease is considered chronic when it persists beyond 4-6 weeks after treatment. These can be secondary to certain infectious, inflammatory, or neoplastic conditions. Computed tomography of the chest is usually performed in this set of patients to identify characteristic imaging findings. Familiarity with the differential diagnosis and characteristic imaging findings for chronic airspace disease is very important for guiding patient's management in a timely fashion.

[Bronchiectasis imaging]

Bronchiectasis are defined as an irreversible focal or diffuse dilatation of the bronchi and can be associated with significant morbidity. The prevalence is currently increasing, probably due to an increased use of thoracic computed tomography (CT). Indeed, the diagnosis relies on imaging and chest CT is the gold standard technique. The main diagnosis criterion is an increased bronchial diameter as compared to that of the companion artery. However, false positives are possible when the artery diameter is decreased, which is called pseudo-bronchiectasis. Other features such as the lack of bronchial tapering, and visibility of bronchi within 1cm of the pleural surface are also diagnostic criteria, and other CT features of bronchial disease are commonly seen. Thoracic imaging also allows severity assessment and long-term monitoring of structural abnormalities. The distribution pattern and the presence of associated findings on chest CT help identifying specific causes of bronchiectasis. Lung MRI and ultra-low dose CT and are promising imaging modalities that may play a role in the future. The objectives of this review are to describe imaging features for the diagnosis and severity assessment of bronchiectasis, to review findings suggesting the cause of bronchiectasis, and to present the new developments in bronchiectasis imaging.

Neutrophil extracellular traps contribute to the pathogenesis of acid-aspiration-induced ALI/ARDS

Background

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a manifestation of systemic inflammation in the lungs, but the factors that trigger inflammation in ALI/ARDS are unclear. We hypothesized that neutrophil extracellular traps (NETs) contribute to the pathogenesis of acid aspiration-induced ALI/ARDS.

Results

Analysis of bronchial aspirates from ARDS patients showed that NETs were significantly correlated with the degree of ARDS (r = -0.5846, p = 0.0359). NETs in bronchoalveolar lavage fluid of acid-aspiration mice were significantly higher (141.6 ± 23.08) at 3 h after injury than those in the sham group (1234 ± 101.9; p = 0.003, n = 5 per group). Exogenous NETs aggravated lung injury, while alvelestat and DNase markedly attenuated the intensity of ARDS.

Materials and Methods

We investigated whether NETs are involved in the severity of gastric aspiration-induced ARDS. Then, a hydrochloric acid aspiration-induced ALI murine model was used to assess whether NETs are pathogenic and whether targeting NETs is protective. Exogenous NETs were administered to mice. Alvelestat can inhibit neutrophil elastase (NE), which serves an important role in NET formation, so we investigated whether alvelestat could protect against ALI in cell and mouse models.

Conclusions

NETs may contribute to ALI/ARDS by promoting tissue damage and systemic inflammation. Targeting NETs by alvelestat may be a potential therapeutic strategy.

Chest CT findings in patients with dysphagia and aspiration: a systematic review

The objective of this systematic review was to characterize chest CT findings in patients with dysphagia and pulmonary aspiration, identifying the characteristics and the methods used. The studies were selected from among those indexed in the Brazilian Virtual Library of Health, LILACS, Indice Bibliográfico Español de Ciencias de la Salud, Medline, Cochrane Library, SciELO, and PubMed databases. The search was carried out between June and July of 2016. Five articles were included and reviewed, all of them carried out in the last five years, published in English, and coming from different countries. The sample size in the selected studies ranged from 43 to 56 patients, with a predominance of adult and elderly subjects. The tomographic findings in patients with dysphagia-related aspiration were varied, including bronchiectasis, bronchial wall thickening, pulmonary nodules, consolidations, pleural effusion, ground-glass attenuation, atelectasis, septal thickening, fibrosis, and air trapping. Evidence suggests that chest CT findings in patients with aspiration are diverse. In this review, it was not possible to establish a consensus that could characterize a pattern of pulmonary aspiration in patients with dysphagia, further studies of the topic being needed.

Aspiration-related organizing pneumonia complicating laparoscopic adjustable gastric banding: A lung cancer mimicker

There are several described pulmonary complications due to laparoscopic adjustable gastric banding. We report a rare case of a 32-year-old male who presented with pulmonary symptoms and a solitary lung mass 12 years after laparoscopic adjustable gastric banding. A bronchoscopic lung biopsy showed organizing pneumonia that was induced by aspiration pneumonia. The atypical radiological appearance of the aspiration pneumonia may pose a diagnostic challenge, and clinicians' awareness regarding such an entity is needed to avoid unnecessary intervention.

Pulmonary involvement in systemic sclerosis

Systemic sclerosis (SSc) is a multi-systemic autoimmune disease that mainly affects the skin, lungs, gastrointestinal tract, heart and kidneys. Pulmonary disease in patients with SSc is strongly associated with mortality. The mechanisms involved into its pathophysiology include the activation of autoimmune cells and hyperplasia of fibroblasts with an increased capacity to produce collagen and diminished collagen breakdown. Although pulmonary biopsy is the gold standard for the diagnosis of interstitial lung disease in SSc, the most commonly used method is high-resolution computed tomography due to its high sensitivity and specificity. Herein, a comprehensive review on the pulmonary involvement in SSc is presented highlighting the radiologic-pathologic correlations.

Pulmonary computed tomography findings in patients with chronic aspiration detected by videofluoroscopic swallowing study

OBJECTIVE

To demonstrate CT findings in patients with chronic aspiration compared with a control group without aspiration, as detected by the videofluoroscopic swallowing study (VFSS).

METHODS

This retrospective, observational study included patients with and without diagnoses of aspiration confirmed by VFSS, who underwent CT examination of the lungs between 2010 and 2014. Two radiologists blinded to the presence of aspiration reviewed the images to detect the presence of any abnormality. Consensus was reached with a third radiologist. CT pulmonary findings (bronchial thickening, bronchiolectasis, centrilobular nodules, ground-glass opacities, atelectasis, consolidation and air trapping) were compared between the groups using the χ(2) test, with a significance level of 0.05.

RESULTS

A total of 56 patients (28 patients with diagnoses of aspiration; 52% male, mean age 65 ± 15 years) were included in the study. Patients with aspiration were more likely to than those in the control group to demonstrate atelectasis, centrilobular nodules, bronchiolectasis, consolidation and ground-glass opacities (all p < 0.05), with a significant predilection for the lower lobes (p < 0.001). Bronchial wall thickening and air trapping did not differ between groups.

CONCLUSION

Atelectasis, centrilobular nodules, bronchiolectasis, consolidation and ground-glass opacities occurred more frequently in patients with aspiration than in those without aspiration, with a pronounced tendency for distribution in the lower lobes.

ADVANCES IN KNOWLEDGE

CT findings of aspiration are very important, as pulmonary symptoms may be the first manifestation of this disorder. Knowledge of these findings is essential to enable the early diagnosis of aspiration disorders and prevent lung damage.

Dysphagia, dystussia, and aspiration pneumonia in elderly people

Despite the development and wide distribution of guidelines for pneumonia, death from pneumonia is increasing due to population aging. Conventionally, aspiration pneumonia was mainly thought to be one of the infectious diseases. However, we have proven that chronic repeated aspiration of a small amount of sterile material can cause the usual type of aspiration pneumonia in mouse lung. Moreover, chronic repeated aspiration of small amounts induced chronic inflammation in both frail elderly people and mouse lung. These observations suggest the need for a paradigm shift of the treatment for pneumonia in the elderly. Since aspiration pneumonia is fundamentally based on dysphagia, we should shift the therapy for aspiration pneumonia from pathogen-oriented therapy to function-oriented therapy. Function-oriented therapy in aspiration pneumonia means therapy focusing on slowing or reversing the functional decline that occurs as part of the aging process, such as "dementia → dysphagia → dystussia → atussia → silent aspiration". Atussia is ultimate dysfunction of cough physiology, and aspiration with atussia is called silent aspiration, which leads to the development of life-threatening aspiration pneumonia. Research pursuing effective strategies to restore function in the elderly is warranted in order to decrease pneumonia deaths in elderly people.

Clinical characteristics of lung abscess in children: 15-year experience at two university hospitals

Purpose

Information on the clinical features of lung abscess, which is uncommon in children, at hospitalizationis helpful to anticipate the disease course and management. There is no report concerning lung abscess in Korean children. We aimed to identify the clinical characteristics of pediatric lung abscess and compare the difference between primary and secondary abscess groups.

Methods

The medical records of 11 lung abscess patients (7 males and 4 females) from March 1998 to August 2011 at two university hospitals were retrospectively reviewed. The clinical characteristics, symptoms, underlying disease, laboratory and radiologic findings, microbiological results, and treatments were examined.

Results

Six patients had underlying structural-related problems (e.g., skeletal anomalies). No immunologic or hematologic problem was recorded. The mean ages of the primary and secondary groups were 2.4 and 5.3 years, respectively, but the difference was not statistically significant. The mean length of hospital stay was similar in both groups (22.8 days vs. 21.4 days). Immunologic studies were performed in 3 patients; the results were within the normal range. Most patients had prominent leukocytosis. Seven and 4 patients had right and left lung abscess, respectively. Staphylococcus aureus, Streptococcus pneumoniae, and antimycoplasma antibodies were detected in both groups. Two patients with primary lung abscess were administered antibiotics in the absence of other procedures, while 8 underwent interventional procedures, including 5 with secondary abscess.

Conclusion

The most common symptoms were fever and cough. All patients in the primary group were younger than 3 years. Structural problems were dominant. Most patients required interventional procedures and antibiotics.

Diffuse aspiration bronchiolitis: analysis of 20 consecutive patients

OBJECTIVE

Aspiration can cause a variety of pulmonary syndromes, some of which are not well recognized. The objective of this study was to assess the demographic, clinical, radiological, and histopathological correlates of diffuse aspiration bronchiolitis (DAB), a bronchiolocentric disorder caused by recurrent aspiration.

METHODS

This was a retrospective study of 20 consecutive patients with DAB seen at the Mayo Clinic in Rochester, Minnesota, between January 1, 1998 and June 30, 2014.

RESULTS

The median age of the patients was 56.5 years (range, 22-76 years), and the male/female ratio was 2.3:1.0. In 18 patients, the diagnosis of DAB was based on the results of a lung biopsy; in the 2 remaining patients, it was based on clinical and radiological features, together with documented aspiration observed in a videofluoroscopic swallow study. In 19 patients (95%), we identified predisposing factors for aspiration, including gastroesophageal reflux disease (GERD), drug abuse, and dysphagia. Common presenting features included cough, sputum production, dyspnea, and fever. Twelve patients (60%) had a history of recurrent pneumonia. In all of the patients, chest CT revealed bilateral pulmonary infiltrates consisting of micronodules and tree-in-bud opacities. In the majority of patients, interventions aimed at preventing recurrent aspiration (e.g., anti-GERD therapies) led to improvement in the symptoms of DAB.

CONCLUSIONS

Young to middle-aged subjects with recognizable predisposing factors for aspiration and who report a history of recurrent pneumonia are at increased risk for DAB. Although DAB is not well recognized, certain chest CT features are characteristic of the disorder.

Solitary lung masses due to occult aspiration

BACKGROUND

Aspiration occurs commonly, at times clinically occult, and is recognized to cause a widening spectrum of lung disorders. Presentation of aspiration as a lung mass has not been described.

METHODS

Among cases of aspiration-related pulmonary diseases diagnosed at Mayo Clinic (Rochester, Minn) from 2007 to 2013, 3 patients were identified to have presented with a solitary lung mass lesion.

RESULTS

The age of 3 patients, all men with a history of gastroesophageal reflux disease, ranged from 53 to 65 years. All patients presented with dyspnea, cough, and intermittent fevers. Chest computed tomography in each patient demonstrated malignant-appearing solitary lung mass, cavitated in 2 patients. Two patients underwent positron emission tomography, which showed intense fluorodeoxyglucose uptake in the lung mass for both. Surgical lung resection revealed acute and organizing pneumonia with giant cell reaction to foreign material, consistent with aspiration in all 3 patients. None of these lung masses were located in the "dependent" (posterior or basal) lung zones. These patients were managed with antireflux medical therapy; 1 patient underwent a Nissen fundoplication procedure for recurrent symptoms. No additional aspiration-related complications occurred during the follow-up period ranging from 24 to 84 months.

CONCLUSIONS

Aspiration-related pulmonary complications can present as a solitary lung mass that may not be located in dependent lung zones, which have traditionally been associated with aspiration-related pulmonary diseases.

To breathe or not to breathe: a review of artificial airway placement and related complications

Artificial airway devices are commonly used to provide adequate ventilation and/or oxygenation in multiple clinical settings, both emergent and nonemergent. These frequently used devices include laryngeal mask airway, esophageal-tracheal combitube, endotracheal tube, and tracheostomy tube and are associated with various acute and late complications. Clinically, this may vary from mild discomfort to a potentially life-threatening situation. Radiologically, these devices and their acute and late complications have characteristic imaging findings which can be detected primarily on radiographs and computed tomography. We review appropriate positioning of these artificial airway devices and illustrate associated complications including inadequate positioning of the endotracheal tube, pulmonary aspiration, tracheal laceration or perforation, paranasal sinusitis, vocal cord paralysis, post-intubation tracheal stenosis, cuff overinflation with vascular compression, and others. Radiologists must recognize and understand the potential complications of intubation to promptly guide management and avoid long-term or even deadly consequences.

Aspiration-related acute respiratory distress syndrome in acute stroke patient

Background

Aspiration of oral or gastric contents into the larynx and lower respiratory tract is a common problem in acute stroke patients, which significantly increases the incidence of acute respiratory distress syndrome (ARDS). However, little is known about the clinical characteristics of aspiration-related ARDS in acute stroke patients.

Methods

Over 17-month period a retrospective cohort study was done on 1495 consecutive patients with acute stroke. The data including demographic characteristics, clinical manifestations, laboratory examinations, chest imaging, and hospital discharge status were collected to analysis.

Results

Aspiration-related ARDS was diagnosed in 54 patients (3.6%). The most common presenting symptom was tachypnea (respiratory rate ≥25 breaths/min) in 50 cases. Computed tomography (CT) images usually demonstrated diffuse ground-glass opacities (GGOs) and inhomogeneous patchy consolidations involving the low lobes. Age, NIHSS score, GCS score, dysphagia, dysarthria, hemoglobin concentration, serum aspertate aminotransferase (AST), serum albumin, serum sodium, and admission glucose level were independently associated with aspiration-related ARDS (odds ratio (OR) 1.05, 95% confidence interval (CI) (1.04–1.07); OR 2.87, (2.68–3.63); OR 4.21, (3.57–5.09); OR 2.18, (1.23–3.86); OR 1.67, (1.31–2.14); OR 2.31, (1.11–4.84); OR 1.68, (1.01–2.80); OR 2.15, (1.19–3.90); OR 1.92, (1.10–3.36) and OR 1.14, (1.06–1.21) respectively).

Conclusions

Aspiration-related ARDS frequently occurs in acute stroke patient with impairment consciousness. It is advisable that performing chest CT timely may identify disease early and prompt treatment to rescue patients.

Prophylactic tracheal intubation for upper GI bleeding: A meta-analysis

AIM: To evaluate usefulness of prophylactically intubating upper gastrointestinal bleeding (UGIB) patients.

METHODS: UGIB results in a significant number of hospital admissions annually with endoscopy being the key intervention. In these patients, risks are associated with the bleeding and the procedure, including pulmonary aspiration. However, very little literature is available assessing the use of prophylactic endotracheal intubation on aspiration in these patients. A comprehensive search was performed in May 2014 in Scopus, CINAHL, Cochrane databases, PubMed/Medline, Embase, and published abstracts from national gastroenterology meetings in the United States (2004-2014). Included studies examined UGIB patients and compared prophylactic intubation to no intubation before endoscopy. Meta-analysis was conducted using RevMan 5.2 by Mantel-Haenszel and DerSimonian and Laird models with results presented as odds ratio for aspiration, pneumonia (within 48 h), and mortality. Funnel plots were utilized for publication bias and I² measure of inconsistency for heterogeneity assessments.

RESULTS: Initial search identified 571 articles. Of these articles, 10 relevant peer-reviewed articles in English and two relevant abstracts were selected to review by two independent authors (Almashhrawi AA and Bechtold ML). Of these studies, eight were excluded: Five did not have a control arm, one was a letter the editor, one was a survey study, and one was focused on prevention of UGIB. Therefore, four studies (N = 367) were included. Of the UGIB patients prophylactically intubated before endoscopy, pneumonia (within 48 h) was identified in 20 of 134 (14.9%) patients as compared to 5 of 95 (5.3%) patients that were not intubated prophylactically (P = 0.02). Despite observed trends, no significant differences were found for mortality (P = 0.18) or aspiration (P = 0.11).

CONCLUSION: Pneumonia within 48 h is more likely in UGIB patients who received prophylactic endotracheal intubation prior to endoscopy.