Mucociliary clearance is impaired in acutely ill patients

Dopamine, norepinephrine, and vasopressin accelerate particle transport velocity in murine tracheal epithelium via substance-specific receptor pathways: dependency on intra- and extracellular Ca2+ sources

Background

The unique ability of the respiratory tract to protect the integrity of the airways by removing potentially harmful substances is defined as mucociliary clearance. This complex physiological mechanism protects the lower airways by ridding them of pollutants and pathogens. This study aimed to evaluate the potential influence of clinically relevant vasopressors on mucociliary clearance.

Material and methods

The particle transport velocity (PTV) of isolated murine tracheae was measured as a surrogate for mucociliary clearance under the influence of dopamine, norepinephrine, and vasopressin. Inhibitory substances were applied to elucidate relevant signal transduction cascades and the value and origin of calcium ions. Reverse-transcription polymerase chain reactions (RT-PCR) were performed to identify the expression of vasopressin receptor subtypes.

Results

Dopamine, norepinephrine, and vasopressin significantly increased the PTV in a dose-dependent manner with half maximal effective concentrations of 0.58 µM, 1.21 µM, and 0.10 µM, respectively. Each substance increased the PTV via separate receptor pathways. While dopamine acted on D1-like receptors to increase the PTV, norepinephrine acted on β-adrenergic receptors, and vasopressin acted on V1a receptors. RT-PCR revealed the expression of V1a in the murine whole trachea and tracheal epithelium. PTV increased when protein kinase A was inhibited and norepinephrine or vasopressin were applied, but not when dopamine was applied. Phospholipase C inhibition decreased the PTV when vasopressin was applied. In general, maximum PTV was significantly reduced when extracellular calcium entry was inhibited. When intracellular calcium stores were depleted, no increase in PTV was observed after administering all three substances. Inositol trisphosphate receptor activation was found to be pivotal in the increase in murine PTV after applying dopamine and vasopressin.

Discussion

Dopamine, norepinephrine, and vasopressin accelerate the murine PTV via substance-specific receptor pathways. Further investigations should assess the value and interaction of these substances on mucociliary clearance in clinical practice.

Effects of mechanical insufflation-exsufflation on ventilator-free days in intensive care unit subjects with sputum retention; a randomized clinical trial

BACKGROUND

Mechanical insufflation-exsufflation (MI-E) facilitates extubation. However, its potential to reduce the duration of ventilator use remains unclear. Therefore, the present study investigated whether the use of MI-E shortened the duration of mechanical ventilation in patients with high sputum retention.

METHODS

A randomized open-label trial was conducted at a single intensive care unit (ICU) in Japan between November 2017 and June 2019. Ventilated subjects requiring suctioning at least once every hour due to sputum retention were randomly assigned to the MI-E group or conventional care group. The primary endpoint was the number of ventilator-free days on day 28. Secondary endpoints were ventilator days in surviving subjects, the length of ICU stay, and mortality and tracheostomy rates among survivors.

RESULTS

Forty-eight subjects (81% males) with a median age of 72 years (interquartile range [IQR], 65-85 years) were enrolled. There were 27 subjects in the MI-E group and 21 in the control group. The median number of ventilator-free days was 21 (IQR, 13-24) and 18, respectively (IQR, 0-23) (P = .38). No significant differences were observed in the ICU length of stay (median, 10 days (IQR, 7-12) vs 12 days (IQR, 6-15); P = .31), mortality rate (19% vs 15%; odds ratio [OR], 1.36 [0.28-6.50]; P = .69), or tracheostomy rate among survivors (14% vs 28%; OR, 0.40 [0.08-1.91]; P = .25).

CONCLUSION

In ventilated subjects in the ICU with high sputum retention, the use of MI-E did not significantly increase the number of ventilator-free days over that with conventional care.

The Nasal Microarchitecture: How Does Tracheostomy Affect it?

This study aims to evaluate the histological changes in the nasal mucosa post Tracheostomy. A prospective observational study was done on 30 patients undergoing Tracheostomy after obtaining written informed consent from patients/legally accepted representatives. Prior to Tracheostomy, anterior rhinoscopy was done, and findings were noted; nasal mucosal biopsy was obtained from the inferior turbinate. The patients enrolled were followed up for four weeks, and in the patients still having Tracheostomy, repeat inferior turbinate biopsies were taken and compared. Statistically significant atrophy of lining epithelium was seen in 80% of the subjects, i.e., pseudostratified lining epithelium at Baseline with multilayered appearance changed to a single layer of flattened cells at follow-up. There was also a marked reduction in the number of seromucinous glands in the stroma at follow-up in 80% of the subjects. Additionally, fibrosis in the stroma was noted in 43.3% of subjects at follow-up. The results from this study indicate that Tracheostomy, likely as a result of nasal airflow deprivation, brings about significant changes in the microanatomy of the nasal airway. The extent of this causation and its implication in nasal pathology must be studied in larger populations with extended follow-up periods.

Mechanical insufflation-exsufflation for invasively ventilated critically ill patients-A focus group study

INTRODUCTION

Mechanical Insufflation-Exsufflation (MI-E) is used as an airway clearance intervention in primary care (home ventilation), long-term care (prolonged rehabilitation after intensive care, neuromuscular diseases, and spinal cord injury), and increasingly in acute care in intensive care units (ICU).

AIM

We sought to develop in-depth understanding of factors influencing decision-making processes of health care professionals regarding initiation, escalation, de-escalation, and discontinuation of MI-E for invasively ventilated patients including perceived barriers and facilitators to use.

METHODS

We conducted focus groups (3 in the Netherlands; 1 with participants from four European countries) with clinicians representing the ICU interprofessional team and with variable experience of MI-E. The semi-structured interview guide was informed by the Theoretical Domains Framework (TDF). Two researchers independently coded data for directed content analysis using codes developed from the TDF.

RESULTS

A purposive sample of 35 health care professionals participated. Experience varied from infrequent to several years of frequent MI-E use in different patient populations. We identified four main themes: (1) knowledge; (2) beliefs; (3) clinical decision-making; and (4) future adoption.

CONCLUSION

Interprofessional knowledge and expertise of MI-E in invasively ventilated patients is limited due to minimal available evidence and adoption. Participants believed MI-E a potentially useful intervention for airway clearance and inclusion in weaning protocols when more evidence is available.

RELEVANCE TO CLINICAL PRACTICE

This focus group study provides an overview of current practice, knowledge and expertise, and barriers and facilitators to using MI-E in mechanically ventilated patients. From these data, it is evident there is a need to develop further clinical expertise and evidence of efficacy to further understand the role of MI-E as an airway clearance technique for ventilated patients.

The respiratory microbiota and its impact on health and disease in dogs and cats: A One Health perspective

Healthy lungs were long thought of as sterile, with presence of bacteria identified by culture representing contamination. Recent advances in metagenomics have refuted this belief by detecting rich, diverse, and complex microbial communities in the healthy lower airways of many species, albeit at low concentrations. Although research has only begun to investigate causality and potential mechanisms, alterations in these microbial communities (known as dysbiosis) have been described in association with inflammatory, infectious, and neoplastic respiratory diseases in humans. Similar studies in dogs and cats are scarce. The microbial communities in the respiratory tract are linked to distant microbial communities such as in the gut (ie, the gut-lung axis), allowing interplay of microbes and microbial products in health and disease. This review summarizes considerations for studying local microbial communities, key features of the respiratory microbiota and its role in the gut-lung axis, current understanding of the healthy respiratory microbiota, and examples of dysbiosis in selected respiratory diseases of dogs and cats.

A 20:1 synergetic mixture of cafedrine/theodrenaline accelerates particle transport velocity in murine tracheal epithelium via IP3 receptor-associated calcium release

Background: Mucociliary clearance is a pivotal physiological mechanism that protects the lung by ridding the lower airways of pollution and colonization by pathogens, thereby preventing infections. The fixed 20:1 combination of cafedrine and theodrenaline has been used to treat perioperative hypotension or hypotensive states due to emergency situations since the 1960s. Because mucociliary clearance is impaired during mechanical ventilation and critical illness, the present study aimed to evaluate the influence of cafedrine/theodrenaline on mucociliary clearance. Material and Methods: The particle transport velocity (PTV) of murine trachea preparations was measured as a surrogate for mucociliary clearance under the influence of cafedrine/theodrenaline, cafedrine alone, and theodrenaline alone. Inhibitory substances were applied to elucidate relevant signal transduction cascades. Results: All three applications of the combination of cafedrine/theodrenaline, cafedrine alone, or theodrenaline alone induced a sharp increase in PTV in a concentration-dependent manner with median effective concentrations of 0.46 µM (consisting of 9.6 µM cafedrine and 0.46 µM theodrenaline), 408 and 4 μM, respectively. The signal transduction cascades were similar for the effects of both cafedrine and theodrenaline at the murine respiratory epithelium. While PTV remained at its baseline value after non-selective inhibition of β-adrenergic receptors and selective inhibition of β1 receptors, cafedrine/theodrenaline, cafedrine alone, or theodrenaline alone increased PTV despite the inhibition of the protein kinase A. However, IP3 receptor activation was found to be the pivotal mechanism leading to the increase in murine PTV, which was abolished when IP3 receptors were inhibited. Depleting intracellular calcium stores with caffeine confirmed calcium as another crucial messenger altering the PTV after the application of cafedrine/theodrenaline. Discussion: Cafedrine/theodrenaline, cafedrine alone, and theodrenaline alone exert their effects via IP3 receptor-associated calcium release that is ultimately triggered by β1-adrenergic receptor stimulation. Synergistic effects at the β1-adrenergic receptor are highly relevant to alter the PTV of the respiratory epithelium at clinically relevant concentrations. Further investigations are needed to assess the value of cafedrine/theodrenaline-mediated alterations in mucociliary function in clinical practice.

Mechanical insufflation-exsufflation to promote extubation success in critically ill adults on intensive care: protocol for a randomised controlled feasibility trial

BACKGROUND

Extubation failure, defined as reintubation within 48 h, is associated with increased intensive care unit (ICU) length of stay and higher mortality risk. One cause of extubation failure is secretion retention, resulting from an inability to cough effectively. Mechanical insufflation-exsufflation (MI-E) simulates a cough aiding secretion clearance. However, MI-E is not routinely used in the ICU for invasively ventilated patients. This study aims to determine feasibility and acceptability of a randomised controlled trial (RCT) examining MI-E use to promote extubation success in intubated, ventilated adults.

METHODS

It is a single-centre, feasibility RCT with semi-structured interviews, economic scoping, and exploratory physiology study. The feasibility RCT (n = 50) will compare standard care to a MI-E protocol including a minimum of two MI-E sessions via the endotracheal tube prior to extubation. Post-extubation, MI-E will be delivered via facemask or mouthpiece up to two times/day for 48 h. MI-E settings will be individualised. All patients will receive standard care (no MI-E) in relation to mechanical ventilation, weaning, rehabilitation, physiotherapy techniques such as positioning, manual airway clearance techniques, manual/ventilator hyperinflation, endotracheal suctioning, and nebulisation. Clinical data collection will occur before, on completion, and 5-min post-physiotherapy sessions (intervention/control arms). Resource use will be calculated for each 24-h period. Analyses will be descriptive and address feasibility outcomes including participant recruitment and attrition, proportion of MI-E treatment sessions completed, dataset completeness, and frequency of adverse events and acceptability. Semi-structured online interviews informed by the Theoretical Framework of Acceptability (TFA) with patients, clinicians, and family members will explore the acceptability of the MI-E intervention and study processes. Interview data will be analysed using reflexive thematic analysis based on TFA domains through first-level coding. The embedded physiology study will use electrical impedance tomography and lung ultrasound to explore lung recruitment and de-recruitment during MI-E in a subset of 5-10 patients.

DISCUSSION

This study will examine feasibility and acceptability of a RCT protocol of MI-E to promote extubation success. Study findings will inform design modification and conduct of a future adequately powered trial. Furthermore, the study will contribute and advance the understanding of MI-E use in critically ill intubated adults.

TRIAL REGISTRATION

ISRCTN 24603037; IRAS 303674.

Echinocandins Accelerate Particle Transport Velocity in the Murine Tracheal Epithelium: Dependency on Intracellular Ca2+ Stores

The mucociliary clearance of lower airways is modulated by different physiologic stimuli and also by pathophysiologic agents like polluting substances or pharmaceutical molecules. In the present investigation, we measured the particle transport velocity (PTV) of mouse tracheae as a surrogate for mucociliary clearance. In mouse tracheal preparations, we detected a sustained increase in the PTV under the application of the echinocandins caspofungin, anidulafungin, and micafungin. In further experiments, we observed the effects of echinocandins on the PTV were dependent on intracellular Ca²⁺ homeostasis. In Ca²⁺-free buffer solutions, the amplitude of the echinocandin-evoked rise in the PTV was significantly reduced relative to that in the experiments in Ca²⁺-containing solutions. Depletion of intracellular Ca²⁺ stores of the endoplasmic reticulum (ER) by caffeine completely prevented an increase in the PTV with subsequent caspofungin applications. Mitochondrial Ca²⁺ stores seemed to be unaffected by echinocandin treatment. We also observed no altered generation of reactive oxygen species under the application of echinocandins as probable mediators of the PTV. Consequently, the observed echinocandin effects on the PTV depend upon the Ca²⁺ influx and Ca²⁺ contents of the ER. We assume that all three echinocandins act intracellularly on ER Ca²⁺ stores to activate Ca²⁺-dependent signal transduction cascades, enhancing the PTV.

Mechanical Insufflation-exsufflation for the Prevention of Ventilator-associated Pneumonia in Intensive Care Units: A Retrospective Cohort Study

Aim

Ventilator-associated pneumonia (VAP) is the most common intensive care unit (ICU)-acquired infection. The current study aimed to assess the efficacy of mechanical insufflation-exsufflation (MI-E) in preventing VAP in critically ill patients.

Materials and methods

This retrospective cohort study was conducted at the ICU of Chiba University Hospital between January 2014 and September 2017. The inclusion criteria were patients who required invasive mechanical ventilation ≥48 hours and those who underwent rehabilitation, including chest physical therapy (CPT). In 2015, the study institution started the use of MI-E in patients with impaired cough reflex. From January to December 2014, patients undergoing CPT were classified under the historical control group, and those who received treatment using MI-E from January 2015 to September 2017 were included in the intervention group. The patients received treatment using MI-E via the endotracheal or tracheostomy tube, with insufflation-exsufflation pressure of 15-40 cm H₂O. The treatment frequency was one to three sessions daily, and a physical therapist who is experienced in using MI-E facilitated the treatment.

Results

From January 2015 to September 2017, 11 patients received treatment using MI-E. Of the 169 patients screened in 2014, 19 underwent CPT. The incidence of VAP was significantly different between the CPT and MI-E groups (84.2% [16/19] vs 26.4% [3/11], p = 0.011). After adjusting for covariates, a multivariate logistic regression analysis was performed, and results showed that the covariates were not associated with the incidence of VAP.

Conclusion

This retrospective cohort study suggests that the use of MI-E in critically ill patients is independently associated with a reduced incidence of VAP.

Clinical significance

Assessing the efficacy of MI-E to prevent VAP.

How to cite this article

Kuroiwa R, Tateishi Y, Oshima T, Inagaki T, Furukawa S, Takemura R, et al. Mechanical Insufflation-exsufflation for the Prevention of Ventilator-associated Pneumonia in Intensive Care Units: A Retrospective Cohort Study. Indian J Crit Care Med 2021;25(1):62-66.

The use of mechanical insufflation-exsufflation in invasively ventilated critically ill adults: a scoping review protocol

BACKGROUND

Critically ill patients receiving invasive ventilation are at risk of sputum retention. Mechanical insufflation-exsufflation (MI-E) is a technique used to mobilise sputum and optimise airway clearance. Recently, interest has increased in the use of mechanical insufflation-exsufflation for invasively ventilated critically ill adults, but evidence for the feasibility, safety and efficacy of this treatment is sparse. The aim of this scoping review is to map current and emerging evidence on the feasibility, safety and efficacy of MI-E for invasively ventilated adult patients with the aim of highlighting knowledge gaps and identifying areas for future research. Specific research questions aim to identify information informing indications and contraindications to the use of MI-E in the invasively ventilated adult, MI-E settings used, outcome measures reported within studies, adverse effects reported and perceived barriers and facilitators to using MI-E reported.

METHODS

We will search electronic databases MEDLINE, EMBASE, CINAHL using the OVID platform, PROSPERO, The Cochrane Library, ISI Web of Science and the International Clinical Trials Registry Platform. Two authors will independently screen citations, extract data and evaluate risk of bias using the Mixed Methods Appraisal Tool. Studies included will present original data and describe MI-E in invasively ventilated adult patients from 1990 onwards. Our exclusion criteria are studies in a paediatric population, editorial pieces or letters and animal or bench studies. Search results will be presented in a PRISMA study flow diagram. Descriptive statistics will be used to summarise quantitative data. For qualitative data relating to barriers and facilitators, we will use content analysis and the Theoretical Domains Framework (TDF) as a conceptual framework. Additional tables and relevant figures will present data addressing our research questions.

DISCUSSION

Our findings will enable us to map current and emerging evidence on the feasibility, safety and efficacy of MI-E for invasively ventilated critically ill adult patients. These data will provide description of how the technique is currently used, support healthcare professionals in their clinical decision making and highlight areas for future research in this important clinical area.

SYSTEMATIC REVIEW REGISTRATION

Open Science Framework submitted on 9 July 2020.  https://osf.io/mpksq/ .

Smoking load reduction is insufficient to downregulate miR-301b, a lung cancer promoter

Several circulating miRNAs identified in the plasma of smokers have been implicated as promoters of nasopharyngeal and lung carcinoma. To investigate the plasma profile of miRNAs in subjects who reduces the number of smoked cigarettes and who quit after six months. We accompanied 28 individuals enrolled in a Smoking Cessation Program over 6 months. At Baseline, clinical characteristics, co-morbidities, and smoking history were similar among subjects. After 6 months, two groups were defined: who successfully quitted smoking (named "quitters", n = 18, mean age 57 years, 11 male) and who reduced the number of cigarettes smoked (20-90%) but failed to quit smoking (named "smokers", n = 10, mean age 52 years, 3 male). No significant clinical changes were observed between groups at baseline and after a 6-month period, however, quitters showed significant downregulations in seven miRNAs at baseline: miR-17 (- 2.90-fold, p = 0.029), miR-20a (- 3.80-fold, p = 0.021); miR-20b (- 4.71-fold, p = 0.027); miR-30a (- 3.95-fold, p = 0.024); miR-93 (- 3.63-fold, p = 0.022); miR-125a (- 1.70-fold, p = 0.038); and miR-195 (- 5.37-fold, p = 0.002), and after a 6-month period in 6 miRNAs: miR-17 (- 5.30-fold, p = 0.012), miR-20a (- 2.04-fold, p = 0.017), miR-20b (- 5.44-fold, p = 0.017), miR-93 (- 4.00-fold, p = 0.041), miR-101 (- 4.82-fold, p = 0.047) and miR-125b (- 3.65-fold, p = 0.025). Using time comparisons, only quitters had significant downregulation in miR-301b (- 2.29-fold, p = 0.038) after 6-month. Reductions in the number of smoked cigarettes was insufficient to change the plasma profile of miRNA after 6 months. Only quitting smoking (100% reduction) significantly downregulated miR-301b related to hypoxic conditions, promotion of cell proliferation, decreases in apoptosis, cancer development, and progression as increases in radiotherapy and chemotherapy resistance.

Lung and gut microbiota are altered by hyperoxia and contribute to oxygen-induced lung injury in mice

Inhaled oxygen, although commonly administered to patients with respiratory disease, causes severe lung injury in animals and is associated with poor clinical outcomes in humans. The relationship between hyperoxia, lung and gut microbiota, and lung injury is unknown. Here, we show that hyperoxia conferred a selective relative growth advantage on oxygen-tolerant respiratory microbial species (e.g., Staphylococcus aureus) as demonstrated by an observational study of critically ill patients receiving mechanical ventilation and experiments using neonatal and adult mouse models. During exposure of mice to hyperoxia, both lung and gut bacterial communities were altered, and these communities contributed to oxygen-induced lung injury. Disruption of lung and gut microbiota preceded lung injury, and variation in microbial communities correlated with variation in lung inflammation. Germ-free mice were protected from oxygen-induced lung injury, and systemic antibiotic treatment selectively modulated the severity of oxygen-induced lung injury in conventionally housed animals. These results suggest that inhaled oxygen may alter lung and gut microbial communities and that these communities could contribute to lung injury.

Is ventilated hospital-acquired pneumonia a worse entity than ventilator-associated pneumonia?

Introduction

Nosocomial pneumonia develops after ≥48 h of hospitalisation and is classified as ventilator-associated pneumonia (VAP) and hospital-acquired pneumonia (HAP); the latter may require mechanical ventilation (V-HAP) or not (NV-HAP).

Main findings

VAP and HAP affect a significant proportion of hospitalised patients and are characterised by poor clinical outcomes. Among them, V-HAP has the greatest 28-day mortality rate followed by VAP and NV-HAP (27.8% versus 18% versus 14.5%, respectively). However, no differences in terms of pathophysiology, underlying microbiological pathways and subsequent therapy have been identified. International guidelines suggest specific flow charts to help clinicians in the therapeutic management of such diseases; however, there are no specific recommendations beyond VAP and HAP classification. HAP subtypes are scarcely considered as different entities and the lack of data from the clinical scenario limits any final conclusion. Hopefully, recent understanding of the pathophysiology of such diseases, as well as the discovery of new therapies, will improve the outcome associated with such pulmonary infections.

Conclusion

Nosocomial pneumonia is a multifaced disease with features of pivotal interest in critical care medicine. Due to the worrisome data on mortality of patients with nosocomial pneumonia, further prospective studies focused on this topic are urgently needed.

Due to the different mortality of each subtype of nosocomial pneumonia, including ventilator-associated pneumonia and hospital-acquired pneumonia requiring mechanical ventilation, new prospective studies are urgently neededhttps://bit.ly/3fFoZ6U

Chest physiotherapy improves lung aeration in hypersecretive critically ill patients: a pilot randomized physiological study

Background

Besides airway suctioning, patients undergoing invasive mechanical ventilation (iMV) benefit of different combinations of chest physiotherapy techniques, to improve mucus removal. To date, little is known about the clearance effects of oscillating devices on patients with acute respiratory failure undergoing iMV. This study aimed to assess (1) the effects of high-frequency chest wall oscillation (HFCWO) on lung aeration and ventilation distribution, as assessed by electrical impedance tomography (EIT), and (2) the effect of the association of HFCWO with recruitment manoeuvres (RM).

Methods

Sixty critically ill patients, 30 classified as normosecretive and 30 as hypersecretive, who received ≥ 48 h of iMV, underwent HFCWO; patients from both subgroups were randomized to receive RM or not, according to two separated randomization sequences. We therefore obtained four arms of 15 patients each. After baseline record (T0), HFCWO was applied for 10 min. At the end of the treatment (T1) or after 1 (T2) and 3 h (T3), EIT data were recorded. At the beginning of each step, closed tracheobronchial suctioning was performed. In the RM subgroup, tracheobronchial suctioning was followed by application of 30 cmH₂O to the patient’s airway for 30 s. At each step, we assessed the change in end-expiratory lung impedance (ΔEELI) and in tidal impedance variation (ΔTIV), and the center of gravity (COG) through EIT. We also analysed arterial blood gases (ABGs).

Results

ΔTIV and COG did not differ between normosecretive and hypersecretive patients. Compared to T0, ΔEELI significantly increased in hypersecretive patients at T2 and T3, irrespective of the RM; on the contrary, no differences were observed in normosecretive patients. No differences of ABGs were recorded.

Conclusions

In hypersecretive patients, HFCWO significantly improved aeration of the dorsal lung region, without affecting ABGs. The application of RM did not provide any further improvements.

Trial registration

Prospectively registered at the Australian New Zealand Clinical Trial Registry (www.anzctr.org.au; number of registration: ACTRN12615001257550; date of registration: 17th November 2015).

Metabolomics and the Microbiome as Biomarkers in Sepsis

Metabolomics is an emerging field of research interest in sepsis. Metabolomics provides new ways of exploring the diagnosis, mechanism, and prognosis of sepsis. Advancements in technologies have enabled significant improvements in identifying novel biomarkers associated with the disease progress of sepsis. The use of metabolomics in the critically ill may provide new approaches to enable precision medicine. Furthermore, the dynamic interactions of the host and its microbiome can lead to further progression of sepsis. Understanding these interactions and the changes in the host's genomics and the microbiome can provide novel preventive and therapeutic strategies against sepsis.

Personalizing the Management of Pneumonia

Pneumonia is a highly prevalent disease with considerable morbidity and mortality. However, diagnosis and therapy still rely on antiquated methods, leading to the vast overuse of antimicrobials, which carries risks for both society and the individual. Furthermore, outcomes in severe pneumonia remain poor. Genomic techniques have the potential to transform the management of pneumonia through deep characterization of pathogens as well as the host response to infection. This characterization will enable the delivery of selective antimicrobials and immunomodulatory therapy that will help to offset the disorder associated with overexuberant immune responses.

Pathophysiological role of respiratory dysbiosis in hospital-acquired pneumonia

Hospital-acquired pneumonia is a major cause of morbidity and mortality. The incidence of hospital-acquired pneumonia remains high globally and treatment can often be ineffective. Here, we review the available data and unanswered questions surrounding hospital-acquired pneumonia, discuss alterations of the respiratory microbiome and of the mucosal immunity in patients admitted to hospital, and explore potential approaches to stratify patients for tailored treatments. The lungs have been considered a sterile organ for decades because microbiological culture techniques had shown negative results. Culture-independent techniques have shown that healthy lungs harbour a diverse and dynamic ecosystem of bacteria, changing our comprehension of respiratory physiopathology. Understanding dysbiosis of the respiratory microbiome and altered mucosal immunity in patients with critical illness holds great promise to develop targeted host-directed immunotherapy to reduce ineffective treatment, to improve patient outcomes, and to tackle the global threat of resistant bacteria that cause these infections.

Altered Viscosity of Nasal Secretions in Postnasal Drip

BACKGROUND

Postnasal drip (PND) is a common symptom associated with upper respiratory tract disorders. It occurs without other symptoms or combined with chronic rhinosinusitis. However, the pathophysiology of PND is debated to this day, and an objective definition of PND has not been established. Therefore, we aimed to elucidate whether the viscosity and volume of nasal secretions as well as the mucociliary clearance and sensitivity of the nasopharynx, or atopy could play a role in the pathophysiology of PND.

METHODS

A prospective case-control study of 30 patients (15 patients with PND and 15 healthy subjects) was conducted. The viscosity and volume of nasal secretions, the nasopharyngeal sensitivity, the mucociliary clearance, and allergic sensitization using a skin prick test were assessed in all subjects.

RESULTS

Viscosity of nasal secretions in patients with PND was significantly increased compared with healthy subjects. Two follow-up measurements in symptom-free intervals showed reversibility of increased viscosity. Analysis of nasopharyngeal sensitivity showed significant reductions in patients with PND. Furthermore, mucociliary clearance seems to be prolonged in patients with PND. The volume of nasal secretions and the atopy screening showed no significant differences in patients with PND compared with healthy individuals.

CONCLUSIONS

Increased viscosity seems to play a relevant role in the pathophysiology of PND. Additionally, delayed mucociliary clearance and hyposensitivity of the nasopharynx may be further components. Earlier concepts of PND, regarding an increased volume of secretions and atopy, do not seem to hold true because our analyses showed no significant difference between cases and control subjects.

Particularities and Clinical Applicability of Saccharin Transit Time Test

Introduction  The importance of mucociliary clearance (MCC) for the respiratory system homeostasis is clear. Therefore, evaluating this defense mechanism is fundamental in scientific research and in the clinical practice of pulmonology and of associated areas. However, MCC evaluation has not been so usual due to the complexity of methods that use radiolabeled particles. Nevertheless, as an interesting alternative, there is the saccharin transit time (STT) test. This method is reproducible, simple to perform, noninvasive, does not demand high costs, and has been widely used in studies of nasal MCC. Although the STT test is widely used, there is still lack of a detailed description of its realization. Objective  The present literature review aims to provide basic information related to the STT test and to present the findings of the previous studies that used this method, discussing variations in its execution, possible influences on the obtained results and limitations of the method, as well as to relate our experience with the use of STT in researches. Data Synthesis  There are several factors that can alter the results obtained from STT tests, which would raise difficulties with proper interpretation and with the discussion of the results among different studies. Conclusions  Saccharin transit time is a widely used method for the evaluation of nasal MCC, and therefore, the standardization related to the previous and concurrent to test orientations, and also its execution, become essential to improve its accuracy, and allow comparisons among different studies.

Comparison of bronchial hygiene techniques in mechanically ventilated patients: a randomized clinical trial

OBJECTIVE

To compare the effects of vibrocompression and hyperinflation with mechanical ventilator techniques alone and in combination (hyperinflation with mechanical ventilator + vibrocompression) on the amount of aspirated secretion and the change in hemodynamic and pulmonary parameters.

METHODS

A randomized clinical trial with critically ill patients on mechanical ventilation conducted in the intensive care unit of a university hospital. The patients were randomly allocated to receive one of the bronchial hygiene techniques for 10 minutes (vibrocompression or hyperinflation with mechanical ventilator or hyperinflation with mechanical ventilator + vibrocompression). Afterwards, the patients were again randomly allocated to receive either the previous randomly allocated technique or only tracheal aspiration. The weight of aspirated secretions (in grams), ventilatory mechanics and cardiopulmonary data before and after the application of the techniques were analyzed. The tracheal reintubation frequency and time and mortality on mechanical ventilation were also evaluated.

RESULTS

A total of 93 patients (29 vibrocompression, 32 hyperinflation with mechanical ventilator and 32 hyperinflation with mechanical ventilator + vibrocompression) on mechanical ventilation for more than 24 hours were included. The hyperinflation with mechanical ventilator + vibrocompression group was the only one that presented a significant increase in aspirated secretions compared to tracheal aspiration alone [0.7g (0.1 - 2.5g) versus 0.2g (0.0 - 0.6g), p value = 0.006].

CONCLUSION

Compared to tracheal aspiration alone, the combination of hyperinflation with mechanical ventilator + vibrocompression techniques was most efficient for increasing the amount of aspirated secretions.

Evaluation of allergic rhinitis with nasal symptoms and nasal mucociliary clearance in patients with fibromyalgia syndrome

BACKROUND

The exact etiopathogenesis of fibromyalgia syndrome (FM) is still unclear but the pathogenesis of FM is associated with neurogenic inflammation. Allergic rhinitis (AR) is a common inflammatory and immunological disease of the nasal mucosa. As a result, it is known that neurogenic inflammation has a role in the pathophysiology of both FM and AR.

OBJECTIVE

The aim of this study was to evaluate AR and nasal allergic inflammation using nasal mucociliary clearance time (NMC) in FM patients.

METHODS

Forty-five FM patients and fifty healthy controls were included in the study. In both groups, AR was evaluated by total nasal symptom scoring (TNSS) and NMC was measured using saccharine transit time test (STT).

RESULTS

TNSS was positive in 9 patients (20%) in the FM group and no positivity in the control group. In FM group, the mean value of TNSS was higher than that of the control group (p= 0.0001). The average value of STT of FM patients was statistically significantly longer when compared to the control group (p= 0.0001).

CONCLUSION

The results we obtained suggest that there is a high possibility of coexistence of FM and AR. As a result, the coexistence of AR and FM cannot be denied but we believe that comprehensive clinical studies should be conducted on this subject.

Hookah smoking impairs nasal mucociliary clearance

INTRODUCTION

Active tobacco smoking has been causally associated with nasal mucociliary clearance (MCC). Smoking through a hookah as an alternative to tobacco smoking has been shown in some scientific studies to have several toxic effects on human health. However, no study has been conducted on the effects on nasal MCC of the hookah as an alternative way of smoking tobacco. The aim of this study is to research whether or not hookah affects nasal MCC.

METHODS

The study included 40 subjects in the control group and 38 subjects in the hookah group. The hookah group was divided into two subgroups: those who used hookahs regularly, once every week (N1 group), and those who used hookahs more than once a week (N2 group, of 2 to 5 sessions/week). The N1 group had 20 subjects, while the N2 group had 18 subjects. The MCC test was performed on each subject and results were recorded in minutes.

RESULTS

The nasal MCC value in the total hookah group was found to be significantly higher than in the control group (p<0.05). The nasal MCC value of the N2 group that used hookahs more than once a week was significantly higher than those of the control group and N1 group that used hookahs once every week (p<0.05).

CONCLUSIONS

Our study has shown that, especially when a hookah was used more than once a week, there was MCC impairment that may put the participant at risk of respiratory tract diseases.

Comparison of Mechanical Insufflation-Exsufflation and Endotracheal Suctioning in Mechanically Ventilated Patients: Effects on Respiratory Mechanics, Hemodynamics, and Volume of Secretions

Context:

Cough assist (CA) is a device to improve bronchial hygiene of patients with secretion in the airways and ineffective cough.

Aims:

To compare the physiological effects and the volume of secretion of mechanical insufflation–exsufflation (CA device) with isolated endotracheal suctioning in mechanically ventilated patients.

Settings and Design:

Randomized crossover trial.

Materials and Methods:

The patients were randomly allocated to the first technique, then the following technique was performed in the next day. We collected the variables related to oxygen saturation, hemodynamics (heart rate, systolic blood pressure, diastolic blood pressure, and mean arterial pressure [MAP]), and respiratory mechanics (tidal volume, minute volume, respiratory rate, and lung compliance and resistance), pre- and postimplementation (immediately and after 15 and 30 min), and the aspirated volume of secretion.

Statistical Analysis Used:

We used two-way analysis of variance followed by the Student–Newman–Keuls t-test to compare the variables at different time points. Student's t-test was used to compare secretion volumes. All data were stored and analyzed in SPSS for Windows Version 19.0. The significance level was set at 5%.

Results:

Forty-three patients were included in the study. When we compared the results before and after the application of the techniques, we observed no significant difference in lung compliance, pulmonary resistance, MAP, peripheral oxygen saturation, and secretion volume in both groups.

Conclusions:

The mechanical insufflation–exsufflation does not alter respiratory mechanics and hemodynamic stability, and it does not improve airway clearance in mechanically ventilated patients.

Airway microbiome research: a modern perspective on surveillance cultures?

The incidence of ventilator-associated pneumonia (VAP) is estimated to be around 10% in a high-risk population. Over the last decade, major improvements have been made in the prevention of VAP, with great cost-effectiveness. However, we still do not understand the exact pathogenesis of VAP. A better understanding might explain why some patients develop ventilator-associated tracheobronchitis, while others develop VAP even though they are infected with the same types of pathogens. Microbiome research has been a hot topic in translational medicine over the past decade. Slowly, microbiome research has also been introduced to the intensive care setting. One of the areas where it may influence our pathophysiological considerations is in VAP. The adapted island has been proposed for the colonization and infection of the respiratory tract. In this model, not only the immigration of bacteria into the lung is important, but elimination and regional growth factors are of equal significance. The importance of these factors can be supported by epidemiological studies. Several small observational studies on the development of the pulmonary microbiome during mechanical ventilation also support this theory. We speculate on the consequences of the newest insights in microbiome research on the prevention and targeted treatment of VAP. We conclude that there is still a strong need for more in-depth analyses of the changes in the microbial composition of the pulmonary microbiome during mechanical ventilation and with the development of VAP.

The use of pulmonary clearance medications in the acutely ill patient

INTRODUCTION

Retention of airway secretions occurs in disease, leading to airway plugging, atelectasis, and worsened respiratory mechanics, making airway clearance an important therapeutic target. Areas covered: Many medications designed to enhance clearance of airway secretions are available. We will review the medications available to enhance airway clearance, their mechanisms of action, and the evidence available for their use in acutely ill patients. Expert commentary: In the cystic fibrosis (CF) population, beneficial effects have been shown in pulmonary function with the use of some of these agents. In the non-CF population, there is limited evidence regarding these medications. While some studies have found benefit, the quality of evidence is low, making it difficult to draw conclusions. While certain patients may derive benefit, the general use of these medications in acutely ill patients without CF cannot be recommended at this time.

Effect of Deviated Nasal Septum Type on Nasal Mucociliary Clearance, Olfactory Function, Quality of Life, and Efficiency of Nasal Surgery

OBJECTIVE

The aim of this study was to analyze the influence of deviated nasal septum (DNS) type on nasal mucociliary clearance, quality of life (QoL), olfactory function, and efficiency of nasal surgery (septoplasty with or without inferior turbinate reduction and partial middle turbinectomy).

METHODS

Fifty patients (20 females and 30 males) with septal deviation were included in the study and were divided into 6 groups according to deviation type after examination by nasal endoscopy and paranasal computed tomography. The saccharin clearance test to evaluate the nasal mucociliary clearance time, Connecticut Chemosensory Clinical Research Center smell test for olfactory function, and sinonasal outcome test-22 (SNOT-22) for patient satisfaction were applied preoperatively and postoperatively at the sixth week after surgery.

RESULT

Nasal mucociliary clearance, smell, and SNOT-22 scores were measured before surgery and at the sixth week following surgery. No significant difference was found in olfactory and SNOT-22 scores for any of the DNS types (both convex and concave sides) (P > 0.05). In addition, there was no difference in the saccharin clearance time (SCT) of the concave and convex sides (P > 0.05). According to the DNS type, the mean SCT of the convex sides showed no difference, but that of the concave sides showed a difference in types 3, 4, 5, and 6. These types had a prolonged SCT (P < 0.05). Olfactory scores revealed no difference postoperatively in types 5 and 6 but were decreased significantly in types 1 to 4 (P < 0.05). There was no significant difference in the healing of both the mucociliary clearance (MCC) and olfactory functions. SNOT-22 results showed a significant decrease in type 3.

CONCLUSION

All DNS types disturb the QoL regarding nasal MCC and olfaction functions. MCC values, olfactory function, and QoL scores are similar among the DNS types. Both sides of the DNS types affect the MCC scores symmetrically. Septal surgery improves olfaction function and QoL at the sixth week following surgery but disturbs nasal MCC; thus, the sixth week is too early to assess nasal MCC.

Cough augmentation techniques for extubation or weaning critically ill patients from mechanical ventilation

BACKGROUND

There are various reasons why weaning and extubation failure occur, but ineffective cough and secretion retention can play a significant role. Cough augmentation techniques, such as lung volume recruitment or manually- and mechanically-assisted cough, are used to prevent and manage respiratory complications associated with chronic conditions, particularly neuromuscular disease, and may improve short- and long-term outcomes for people with acute respiratory failure. However, the role of cough augmentation to facilitate extubation and prevent post-extubation respiratory failure is unclear.

OBJECTIVES

Our primary objective was to determine extubation success using cough augmentation techniques compared to no cough augmentation for critically-ill adults and children with acute respiratory failure admitted to a high-intensity care setting capable of managing mechanically-ventilated people (such as an intensive care unit, specialized weaning centre, respiratory intermediate care unit, or high-dependency unit).Secondary objectives were to determine the effect of cough augmentation techniques on reintubation, weaning success, mechanical ventilation and weaning duration, length of stay (high-intensity care setting and hospital), pneumonia, tracheostomy placement and tracheostomy decannulation, and mortality (high-intensity care setting, hospital, and after hospital discharge). We evaluated harms associated with use of cough augmentation techniques when applied via an artificial airway (or non-invasive mask once extubated/decannulated), including haemodynamic compromise, arrhythmias, pneumothorax, haemoptysis, and mucus plugging requiring airway change and the type of person (such as those with neuromuscular disorders or weakness and spinal cord injury) for whom these techniques may be efficacious.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; Issue 4, 2016), MEDLINE (OvidSP) (1946 to April 2016), Embase (OvidSP) (1980 to April 2016), CINAHL (EBSCOhost) (1982 to April 2016), and ISI Web of Science and Conference Proceedings. We searched the PROSPERO and Joanna Briggs Institute databases, websites of relevant professional societies, and conference abstracts from five professional society annual congresses (2011 to 2015). We did not impose language or other restrictions. We performed a citation search using PubMed and examined reference lists of relevant studies and reviews. We contacted corresponding authors for details of additional published or unpublished work. We searched for unpublished studies and ongoing trials on the International Clinical Trials Registry Platform (apps.who.int/trialsearch) (April 2016).

SELECTION CRITERIA

We included randomized and quasi-randomized controlled trials that evaluated cough augmentation compared to a control group without this intervention. We included non-randomized studies for assessment of harms. We included studies of adults and of children aged four weeks or older, receiving invasive mechanical ventilation in a high-intensity care setting.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts identified by our search methods. Two review authors independently evaluated full-text versions, independently extracted data and assessed risks of bias.

MAIN RESULTS

We screened 2686 citations and included two trials enrolling 95 participants and one cohort study enrolling 17 participants. We assessed one randomized controlled trial as being at unclear risk of bias, and the other at high risk of bias; we assessed the non-randomized study as being at high risk of bias. We were unable to pool data due to the small number of studies meeting our inclusion criteria and therefore present narrative results rather than meta-analyses. One trial of 75 participants reported that extubation success (defined as no need for reintubation within 48 hours) was higher in the mechanical insufflation-exsufflation (MI-E) group (82.9% versus 52.5%, P < 0.05) (risk ratio (RR) 1.58, 95% confidence interval (CI) 1.13 to 2.20, very low-quality evidence). No study reported weaning success or reintubation as distinct from extubation success. One trial reported a statistically significant reduction in mechanical ventilation duration favouring MI-E (mean difference -6.1 days, 95% CI -8.4 to -3.8, very low-quality evidence). One trial reported mortality, with no participant dying in either study group. Adverse events (reported by two trials) included one participant receiving the MI-E protocol experiencing haemodynamic compromise. Nine (22.5%) of the control group compared to two (6%) MI-E participants experienced secretion encumbrance with severe hypoxaemia requiring reintubation (RR 0.25, 95% CI 0.06 to 1.10). In the lung volume recruitment trial, one participant experienced an elevated blood pressure for more than 30 minutes. No participant experienced new-onset arrhythmias, heart rate increased by more than 25%, or a pneumothorax.For outcomes assessed using GRADE, we based our downgrading decisions on unclear risk of bias, inability to assess consistency or publication bias, and uncertainty about the estimate of effect due to the limited number of studies contributing outcome data.

AUTHORS' CONCLUSIONS

The overall quality of evidence on the efficacy of cough augmentation techniques for critically-ill people is very low. Cough augmentation techniques when used in mechanically-ventilated critically-ill people appear to result in few adverse events.

The effects of smoking and smoking cessation on nasal mucociliary clearance, mucus properties and inflammation

OBJECTIVE

The aim of the present study was to assess nasal mucociliary clearance, mucus properties and inflammation in smokers and subjects enrolled in a Smoking Cessation Program (referred to as quitters).

METHOD

A total of 33 subjects with a median (IQR) smoking history of 34 (20-58) pack years were examined for nasal mucociliary clearance using a saccharine transit test, mucus properties using contact angle and sneeze clearability tests, and quantification of inflammatory and epithelial cells, IL-6 and IL-8 concentrations in nasal lavage fluid. Twenty quitters (mean age: 51 years, 9 male) were assessed at baseline, 1 month, 3 months and 12 months after smoking cessation, and 13 smokers (mean age: 52 years, 6 male) were assessed at baseline and after 12 months. Clinicaltrials.gov: NCT02136550.

RESULTS

Smokers and quitters showed similar demographic characteristics and morbidities. At baseline, all subjects showed impaired nasal mucociliary clearance (mean 17.6 min), although 63% and 85% of the quitters demonstrated significant nasal mucociliary clearance improvement at 1 month and 12 months, respectively. At 12 months, quitters also showed mucus sneeze clearability improvement (∼26%), an increased number of macrophages (2-fold) and no changes in mucus contact angle or cytokine concentrations.

CONCLUSION

This study showed that smoking cessation induced early improvements in nasal mucociliary clearance independent of mucus properties and inflammation. Changes in mucus properties were observed after only 12 months of smoking cessation.

The microbiome and critical illness

The central role of the microbiome in critical illness is supported by a half century of experimental and clinical study. The physiological effects of critical illness and the clinical interventions of intensive care substantially alter the microbiome. In turn, the microbiome predicts patients' susceptibility to disease, and manipulation of the microbiome has prevented or modulated critical illness in animal models and clinical trials. This Review surveys the microbial ecology of critically ill patients, presents the facts and unanswered questions surrounding gut-derived sepsis, and explores the radically altered ecosystem of the injured alveolus. The revolution in culture-independent microbiology has provided the tools needed to target the microbiome rationally for the prevention and treatment of critical illness, holding great promise to improve the acute and chronic outcomes of the critically ill.

Effects of 12 weeks of aerobic training on autonomic modulation, mucociliary clearance, and aerobic parameters in patients with COPD

Introduction

Patients with chronic obstructive pulmonary disease (COPD) exhibit aerobic function, autonomic nervous system, and mucociliary clearance alterations. These parameters can be attenuated by aerobic training, which can be applied with continuous or interval efforts. However, the possible effects of aerobic training, using progressively both continuous and interval sessions (ie, linear periodization), require further investigation.

Aim

To analyze the effects of 12-week aerobic training using continuous and interval sessions on autonomic modulation, mucociliary clearance, and aerobic function in patients with COPD.

Methods

Sixteen patients with COPD were divided into an aerobic (continuous and interval) training group (AT) (n=10) and a control group (CG) (n=6). An incremental test (initial speed of 2.0 km·h⁻¹, constant slope of 3%, and increments of 0.5 km·h⁻¹ every 2 minutes) was performed. The training group underwent training for 4 weeks at 60% of the peak velocity reached in the incremental test (vVO_2peak) (50 minutes of continuous effort), followed by 4 weeks of sessions at 75% of vVO_2peak (30 minutes of continuous effort), and 4 weeks of interval training (5×3-minute effort at vVO_2peak, separated by 1 minute of passive recovery). Intensities were adjusted through an incremental test performed at the end of each period.

Results

The AT presented an increase in the high frequency index (ms²) (P=0.04), peak oxygen uptake (VO_2peak) (P=0.01), vVO_2peak (P=0.04), and anaerobic threshold (P=0.02). No significant changes were observed in the CG (P>0.21) group. Neither of the groups presented changes in mucociliary clearance after 12 weeks (AT: P=0.94 and CG: P=0.69).

Conclusion

Twelve weeks of aerobic training (continuous and interval sessions) positively influenced the autonomic modulation and aerobic parameters in patients with COPD. However, mucociliary clearance was not affected by aerobic training.

Effects of rapid maxillary expansion on nasal mucociliary clearance

OBJECTIVE

To evaluate the changes in nasal mucociliary clearance in orthodontic patients after rapid maxillary expansion (RME) therapy.

MATERIALS AND METHODS

Forty-two children (25 boys and 17 girls) participated in this study. The RME group consisted of 21 patients (mean age, 13.8 years), who had undergone RME at the initiation of orthodontic treatment. The control group consisted of 21 subjects (mean age, 13.6 years), who were attending the department of orthodontics for active orthodontic treatment. The nasal mucociliary clearance was assessed by the saccharin test. Saccharin transit times (STTs) were measured for each treated subject before expansion (T1), after RME (T2), and after a 3-month retention period (T3). Records were obtained at the same time intervals for each group.

RESULTS

The STT decreased significantly in the RME group after expansion and retention (P < .05). A statistically significant difference was found when the STTs of the control and RME groups were compared after expansion and retention (P < .05).

CONCLUSIONS

The STTs of young orthodontic patients with maxillary narrowness and without any history of nasal or systemic disease were within normal limits. However, RME increased the mucociliary clearance in patients who had maxillary narrowness, having positive effects on nasal physiology and increasing nasal cavity volume.

Comparison of the coaxial circle circuit with the conventional circle circuit

OBJECTIVE

The coaxial circle system helps prevent heat loss during surgery, and it also acts as a humidifier. This study aimed to compare the coaxial breathing system and the conventional system in their ability to warm and moisturize inhaled gases, and we also analyzed lung function protection and saccharin clearance time in patients who underwent tympanomastoidectomy (TMT) with the aid of these two systems.

MATERIALS AND METHODS

Forty adult patients of ASA physical status I-II were scheduled for elective TMT. A standard volume-dependent ventilator setting was used to establish normocapnia. The coaxial circle system was used in the treated group (n=20), whereas the conventional circuit system was used in the control group (n=20). Saccharin clearance, VC (vital capacity), FRC (functional residual capacity), FEV1 (forced expiratory volume in 1 second), airway pressure, relative humidity and temperature of inspired gas, body temperature and adverse and hemodynamic effects were measured at different perioperative periods.

RESULTS

The relative humidity (mg H2O Lt -1) of inspired gas in the treated group was higher than in the control group at 5, 15, 30, 45, 60 and 90 minutes after anesthesia induction. The temperature of inspired gas (Centigrade) in the treated group was higher than in the control group (p<0.05) after 5, 10, 15, 30, 45, and 90 minutes of anesthesia. Postoperative saccharin clearance time was lower than before the operation in the treated group (p<0.05). Postoperative FRC was lower than preoperative FRC in the study and control groups (p<0.05).

CONCLUSION

The coaxial circle system decreased postoperative saccharin clearance time and increased postoperative FRC, relative humidity and the temperature of inspired fresh gas, without any adverse perioperative effects in patients who underwent TMT.

Mucoactive effects of naringin in lipopolysaccharide-induced acute lung injury mice and beagle dogs

Our previous study has demonstrated that naringin attenuates EGF-induced MUC5AC hypersecretion in A549 cells by suppressing the cooperative activities of MAPKs/AP-1 and IKKs/IκB/NF-κB signaling pathways. However, the volume of airway mucus is determined by two factors including the number of mucous cells and capacity of mucus secretion. The aim of the present study is to explore the mucoactive effects of naringin in lipopolysaccharide (LPS)-induced acute lung injury (ALI) mice and beagle dogs. The results demonstrated that naringin of 12.4 mg/kg treatment significantly decreased LPS-induced enhancement of sputum volume and pulmonary inflammation, remarkably increased the subglottic sputum volume and solids content in sputum of lower trachea, while partially, but not fully, significantly increased the elasticity and viscosity of sputum in lower trachea of beagle dogs. Moreover, the MUC5AC content in BALF and goblet-cells in large airways of LPS-induced ALI mice were significantly attenuated by dexamethasone (5 mg/kg), ambroxol (25 mg/kg), and naringin (15, 60 mg/kg). However, the goblet-cells hyperplasia in small airways induced by LPS was only significantly inhibited by dexamethasone and naringin (60 mg/kg). In conclusion, naringin exhibits mucoactive effects through multiple targets which including reduction of goblet cells hyperplasia and mucus hypersecretion, as well as promotion of sputum excretion.

Young "healthy" smokers have functional and inflammatory changes in the nasal and the lower airways

BACKGROUND

Smoking is responsible for most COPD. Although people with COPD often have concomitant nasal disease, there are few studies that report physiologic or inflammatory changes in the upper airways in young asymptomatic smokers. We investigated physiologic and inflammatory changes in the nasal and lower airways of young smokers and if these changes were related to smoking history.

METHODS

Seventy-two subjects aged between 18 and 35 years (32 healthy nonsmokers and 40 young smokers) participated in this study. We measured nasal mucociliary clearance (MCC), nasal mucus surface contact angle, cell counts, myeloperoxidase and cytokine concentrations in nasal lavage fluid, exhaled breath condensate (EBC) pH, and lung function.

RESULTS

Smokers had faster MCC, an increased number of cells (macrophages, ciliated cells, and goblet cells), increased lavage myeloperoxidase concentration, and decreased EBC pH compared with nonsmokers. There was a significant inverse relationship between pack-year smoking history and EBC pH. There were no differences in lung function or mucus surface properties comparing smokers to nonsmokers.

CONCLUSIONS

Young adult smokers have functional and inflammatory changes in the nasal and lower airways and these correlate with smoking history. However, in these young smokers, smoking history was not associated with pulmonary function decline, probably because it is unlikely that spirometry detects early physiologic changes in the airways.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01877291; URL: www.clinicaltrials.gov.

Mucociliary clearance, airway inflammation and nasal symptoms in urban motorcyclists

OBJECTIVES

There is evidence that outdoor workers exposed to high levels of air pollution exhibit airway inflammation and increased airway symptoms. We hypothesized that these workers would experience increased airway symptoms and decreased nasal mucociliary clearance associated with their exposure to air pollution.

METHODS

In total, 25 non-smoking commercial motorcyclists, aged 18-44 years, were included in this study. These drivers work 8-12 hours per day, 5 days per week, driving on urban streets. Nasal mucociliary clearance was measured by the saccharine transit test; airway acidification was measured by assessing the pH of exhaled breath condensate; and airway symptoms were measured by the Sino-nasal Outcome Test-20 questionnaire. To assess personal air pollution exposure, the subjects used a passive-diffusion nitrogen dioxide (NO2) concentration-monitoring system during the 14 days before each assessment. The associations between NO2 and the airway outcomes were analyzed using the Mann-Whitney test and the Chi-Square test. Clinicaltrials.gov: NCT01976039.

RESULTS

Compared with clearance in healthy adult males, mucociliary clearance was decreased in 32% of the motorcyclists. Additionally, 64% of the motorcyclists had airway acidification and 92% experienced airway symptoms. The median personal NO2 exposure level was 75 mg/m3 for these subjects and a significant association was observed between NO2 and impaired mucociliary clearance (p=0.036).

CONCLUSION

Non-smoking commercial motorcyclists exhibit increased airway symptoms and airway acidification as well as decreased nasal mucociliary clearance, all of which are significantly associated with the amount of exposure to air pollution.

Aging, diabetes, and hypertension are associated with decreased nasal mucociliary clearance

BACKGROUND

We showed previously that nasal mucociliary clearance was decreased in critically ill elderly subjects, most of whom had diabetes mellitus (DM) and/or hypertension (HTN). To determine if these changes were due to the effects of aging, disease, or critical illness, we studied nasal mucociliary clearance and mucus properties in an ambulatory population consisting of young, elderly, and healthy subjects and those with DM, HTN, or both.

METHODS

Of 440 subjects contacted, 252 entered the study. The subjects were divided into the following groups: (1) healthy (n 5 79, 18-94 years, 50 men) and (2) DM and/or HTN, of which 37 had DM (14-90 years, 12 men), 52 had HTN (23-90 years, 12 men), and 84 had both DM and HTN (25-82 years, 33 men). Subjects were also grouped by age: , 40 years, 40 to 59 years, and 60 years. We assessed demographic and clinical data, quality of life using the 36-Item Short Form Health Survey (SF-36) questionnaire, nasal mucociliary clearance using the saccharine transit test (STT), and in vitro mucus properties by examining the sneeze (high airflow) clearability and contact angle. A logistic regression analysis for prolonged STT . 12 min was used, and we controlled for age, sex, and diseases.

RESULTS

Subjects aged . 60 years reported a decreased SF-36 physical component relative to other age groups. Sex, BMI, BP, heart rate, pulse oximetry, blood glucose level, and mucus properties were not associated with prolonged STT. Aging and DM and/or HTN independently increased the risk of prolonged STT.

CONCLUSIONS

Aging and DM, HTN, or both diseases are independently associated with decreased nasal mucociliary clearance. This may predispose toward respiratory infections.

Effects of mechanical insufflation-exsufflation in preventing respiratory failure after extubation: a randomized controlled trial

Introduction

Weaning protocols that include noninvasive ventilation (NIV) decrease re-intubation rates and ICU length of stay. However, impaired airway clearance is associated with NIV failure. Mechanical insufflation-exsufflation (MI-E) has been proven to be very effective in patients receiving NIV. We aimed to assess the efficacy of MI-E as part of an extubation protocol.

Method

Patients with mechanical ventilation (MV) for more than 48 hours with specific inclusion criteria, who successfully tolerated a spontaneous breathing trial (SBT), were randomly allocated before extubation, either for (A) a conventional extubation protocol (control group), or (B) the MI-E extubation protocol (study group). During the postextubation period (48 hours), group A patients received standard medical treatment (SMT), including NIV in case of specific indications, whereas group B received the same postextubation approach plus three daily sessions of mechanical in-exsufflation (MI-E). Reintubation rates, ICU length of stay, and NIV failure rates were analyzed.

Results

Seventy-five patients (26 women) with a mean age of 61.8 ± 17.3 years were randomized to a control group (n = 40; mean SAPS II, 47.8 ± 17.7) and to a study group (n = 35; mean SAPS II, 45.0 ± 15.0). MV time before enrollment was 9.4 ± 4.8 and 10.5 ± 4.1 days for the control and the study group, respectively. In the 48 hours after extubation, 20 control patients (50%) and 14 study patients (40%) used NIV. Study group patients had a significant lower reintubation rate than did controls; six patients (17%) versus 19 patients (48%), P < 0.05; respectively, and a significantly lower time under MV; 17.8 ± 6.4 versus 11.7 ± 3.5 days; P < 0.05; respectively. Considering only the subgroup of patients that used NIV, the reintubation rates related to NIV failure were significantly lower in the study group when compared with controls; two patients (6%) versus 13 (33%); P < 0.05, respectively. Mean ICU length of stay after extubation was significantly lower in the study group when compared with controls (3.1 ± 2.5 versus 9.8 ± 6.7 days; P < 0.05). No differences were found in the total ICU length of stay.

Conclusion

Inclusion of MI-E may reduce reintubation rates with consequent reduction in postextubation ICU length of stay. This technique seems to be efficient in improving the efficacy of NIV in this patient population.

Practice of Humidification During Noninvasive Mechanical Ventilation (NIV): Determinants of Humidification Strategies

Noninvasive ventilation (NIV) has become a standard practice in the hospital and at home for several acute and chronic respiratory diseases. While the routine use of humidification in invasive ventilation has become a standard of care, there is no consensus or standard approach to guide the use of humidification in NIV. This chapter reviews studies that assessed the use of humidification in NIV in patients with different clinical conditions and tries to develop a practical approach for the utility of humidification in NIV. We will try to answer the following key questions:

Who will benefit from humidification?

When to apply humidification?

How to incorporate humidification into NIV?

The validation of a clinical algorithm for the prevention and management of pulmonary dysfunction in intubated adults--a synthesis of evidence and expert opinion

BACKGROUND

Pulmonary dysfunction (PDF) in intubated patients remains a serious and costly complication of intensive care unit care. Optimal cardiopulmonary therapy strategies to prevent and manage PDF need clarification to reduce practice variability. The purpose of this paper is to report on the content validation of an evidence-based clinical management algorithm (EBCMA) aimed at the prevention, identification and management of PDF in critically ill patients.

METHODS

Forty-four draft algorithm statements extracted from the extant literature by the primary research team were verified and rated by research clinicians (n = 7) in an electronic three-round Delphi process. Statements which reached a priori defined consensus [semi-interquartile range (SIQR) <0.5] were collated into the EBCMA.

RESULTS

One hundred per cent response rate. Forty-four statements were added after round one. Consensus was reached on rating of 83% (73/88) statements. Differences in interpretation of the existing evidence base, and variations in accepted clinical practice were identified. Four themes were identified where panel failed to reach consensus.

CONCLUSION

The internationally agreed hierarchical framework of current available evidence and clinical expertise developed through this Delphi process provides clinicians with a tool to inform clinical practice. This tool has the potential to reduce practice variability thereby maximizing safety and treatment outcome. The clinical utility of the EBCMA requires further evaluation.

Effects of biomass burning on nasal mucociliary clearance and mucus properties after sugarcane harvesting

OBJECTIVE

Biofuel from sugarcane is widely produced in developing countries and is a clean and renewable alternative source of energy. However, sugarcane harvesting is mostly performed after biomass burning. The aim of this study was to evaluate the effects of harvesting after biomass burning on nasal mucociliary clearance and the nasal mucus properties of farm workers.

METHODS

Twenty seven sugarcane workers (21-45 years old) were evaluated at the end of two successive time-periods: first at the end of a 6-month harvesting period (harvesting), and then at the end of a 3-month period without harvesting (non-harvesting). Nasal mucociliary clearance was evaluated by the saccharine transit test, and mucus properties were analyzed using in vitro mucus contact angle and mucus transportability by sneeze. Arterial blood pressure, heart rate, respiratory rate, pulse oximetry, body temperature, associated illness, and exhaled carbon monoxide were registered.

RESULTS

Data are presented as mean values (95% confidence interval). The multivariate model analysis adjusted for age, body-mass index, smoking status and years of working with this agricultural practice showed that harvesting yielded prolonged saccharine transit test in 7.83 min (1.88-13.78), increased mucus contact angle in 8.68 degrees (3.18-14.17) and decreased transportability by sneeze in 32.12 mm (-44.83 to -19.42) compared with the non-harvesting period. No significant differences were detected in any of the clinical parameter at either time-period.

CONCLUSION

Sugarcane harvesting after biomass burning negatively affects the first barrier of the respiratory system in farm workers by impairing nasal mucociliary clearance and inducing abnormal mucus properties.

Furosemide impairs nasal mucociliary clearance in humans

Furosemide, a potent diuretic, affects ion and water movement across the respiratory epithelium. However, the effects of furosemide, as clinically used, on mucociliary clearance, a critical respiratory defense mechanism, are still lacking in humans. Fourteen young healthy subjects were assigned to three random interventions, spaced one-week apart: no intervention (control), oral furosemide (40mg), and furosemide+oral volume replacement (F+R). Nasal mucociliary clearance was assessed by saccharine test (STT), and mucus properties were in vitro evaluated by means of contact angle and transportability by sneeze. Urine output and osmolality were also evaluated. Urine output increased and reduced urine osmolality in furosemide and F+R compared to the control condition. STT remained stable in the control group. In contrast, STT increased significantly (40%) after furosemide and F+R. There were no changes in vitro mucus properties in all groups. In conclusion, furosemide prolongs STT in healthy young subjects. This effect is not prevented by fluid replacement, suggesting a direct effect of furosemide on the respiratory epithelium.

Long acting beta2-agonist and corticosteroid restore airway glandular cell function altered by bacterial supernatant

BACKGROUND

Staphylococcus aureus releases virulence factors (VF) that may impair the innate protective functions of airway cells. The aim of this study was to determine whether a long-acting beta2 adrenergic receptor agonist (salmeterol hydroxynaphthoate, Sal) combined with a corticosteroid (fluticasone propionate, FP) was able to regulate ion content and cytokine expression by airway glandular cells after exposure to S. aureus supernatant.

METHODS

A human airway glandular cell line was incubated with S. aureus supernatant for 1 h and then treated with the combination Sal/FP for 4 h. The expression of actin and CFTR proteins was analyzed by immunofluorescence. Videomicroscopy was used to evaluate chloride secretion and X-ray microanalysis to measure the intracellular ion and water content. The pro-inflammatory cytokine expression was assessed by RT-PCR and ELISA.

RESULTS

When the cells were incubated with S. aureus supernatant and then with Sal/FP, the cellular localisation of CFTR was apical compared to the cytoplasmic localisation in cells incubated with S. aureus supernatant alone. The incubation of airway epithelial cells with S. aureus supernatant reduced by 66% the chloride efflux that was fully restored by Sal/FP treatment. We also observed that Sal/FP treatment induced the restoration of ion (Cl and S) and water content within the intracellular secretory granules of airway glandular cells and reduced the bacterial supernatant-dependent increase of pro-inflammatory cytokines IL8 and TNFalpha.

CONCLUSIONS

Our results demonstrate that treatment with the combination of a corticosteroid and a long-acting beta2 adrenergic receptor agonist after bacterial infection restores the airway glandular cell function. Abnormal mucus induced by defective ion transport during pulmonary infection could benefit from treatment with a combination of beta2 adrenergic receptor agonist and glucocorticoid.

Evaluation of the safety of high-frequency chest wall oscillation (HFCWO) therapy in blunt thoracic trauma patients

BACKGROUND

Airway clearance is frequently needed by patients suffering from blunt chest wall trauma. High Frequency Chest Wall Oscillation (HFCWO) has been shown to be effective in helping to clear secretions from the lungs of patients with cystic fibrosis, bronchiectasis, asthma, primary ciliary dyskinesia, emphysema, COPD, and many others. Chest wall trauma patients are at increased risk for development of pulmonary complications related to airway clearance. These patients frequently have chest tubes, drains, catheters, etc. which could become dislodged during HFCWO. This prospective observational study was conducted to determine if HFCWO treatment, as provided by The Vesttrade mark Airway Clearance System (Hill-Rom, Saint Paul, MN), was safe and well tolerated by these patients.

METHODS

Twenty-five blunt thoracic trauma patients were entered into the study. These patients were consented. Each patient was prescribed 2, 15 minute HFCWO treatments per day using The Vest(R) Airway Clearance System (Hill-Rom, Inc., St Paul, MN). The Vest(R) system was set to a frequency of 10-12 Hz and a pressure of 2-3 (arbitrary unit). Physiological parameters were measured before, during, and after treatment. Patients were free to refuse or terminate a treatment early for any reason.

RESULTS

No chest tubes, lines, drains or catheters were dislodged as a result of treatment. One patient with flail chest had a chest tube placed after one treatment due to increasing serous effusion. No treatments were missed and continued without further incident. Post treatment survey showed 76% experienced mild or no pain and more productive cough. Thirty days after discharge there were no deaths or hospital re-admissions.

CONCLUSION

This study suggests that HFCWO treatment is safe for trauma patients with lung and chest wall injuries. These findings support further work to demonstrate the airway clearance benefits of HFCWO treatment.