Airway Opening Research Articles

Severe acute respiratory syndrome coronavirus 2 can be detected in exhaled aerosol sampled during a few minutes of breathing or coughing

BackgroundThe knowledge on the concentration of viral particles in exhaled breath is limited. The aim of this study was to explore if severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) can be detected in aerosol from subjects with the coronavirus disease 2019 (COVID‐19) during various types of breathing and coughing and how infection with SARS‐CoV‐2 may influence the number and size of exhaled aerosol particles.MethodsWe counted and collected endogenous particles in exhaled breath in subjects with COVID‐19 disease by two different impaction‐based methods, during 20 normal breaths, 10 airway opening breaths, and three coughs, respectively. Breath samples were analyzed with reverse transcription real‐time polymerase chain reaction (RT‐PCR).ResultsDetection of RNA in aerosol was possible in 10 out of 25 subjects. Presence of virus RNA in aerosol was mainly found in cough samples (n = 8), but also in airway opening breaths (n = 3) and in normal breaths (n = 4), with no overlap between the methods. No association between viral load in aerosol and number exhaled particles <5 μm was found. Subjects with COVID‐19 exhaled less particles than healthy controls during normal breathing and airway opening breaths (all P < 0.05), but not during cough.ConclusionSARS‐CoV‐2 RNA can be detected in exhaled aerosol, sampled during a limited number of breathing and coughing procedures. Detection in aerosol seemed independent of viral load in the upper airway swab as well as of the exhaled number of particles. The infectious potential of the amount of virus detected in aerosol needs to be further explored.

Surgical procedure and treatment results of pharyngoplasty CWICKs for obstructive sleep apnea

ObjectiveUvulopalatopharyngoplasty (UPPP) is performed as a surgical treatment at the oropharyngeal level for obstructive sleep apnea, but there are problems with variations in treatment effects and postoperative complications. Therefore, to improve those, we have devised and put into practice the so-called CWICKs, which is a modified version of barbed reposition pharyngoplasty as a surgical method. We outline the procedure of CWICKs and report the treatment results in comparison with the conventional UPPP. MethodsCWICKs are surgeries that use resorbable wound closure devices to pull the posterior palatal arch outward and elevate it anteriorly and superiorly to maintain an open upper airway during sleep at the soft palate level. We compared the therapeutic effects of 46 patients evaluated by polysomnography before and after surgery among CWICKs performed in our department between January 2015 and December 2019 and 91 patients who underwent UPPP in our department between January 2000 and December 2008. ResultsIn 46 patients who underwent CWICKs, significant improvement was observed before and after surgery using the apnea hypopnea index (AHI), obstructive apnea index (OAI), ration of each sleep stage, and SpO2 level > 90%. The improvement rate of AHI was 68.4%, and the surgical success rate was 58.7%. Postoperative patient satisfaction was also good, and significant improvement in subjective sleepiness (Epworth Sleepiness Scale) and subjective sleep quality (Pittsburgh Sleep Quality Index) was observed before and after surgery. No postoperative complications such as dysphagia or scar stenosis were observed in any of the patients in the CWICKs group. Compared with the 91 cases of UPPP, which is the conventional method, there was no significant difference in the improvement rate of AHI (p = 0.199), but the improvement rate of OAI had significantly improved (p = 0.013). Regarding the postoperative sleep stage, In the CWICKs group, a significant decrease in stage 1 and a significant increase in stage 2, stage 3, and stage rapid eye movement were observed, whereas in the UPPP group, no significant improvement in stage 3 was observed. Multivariate analysis of surgical success did not show an association with surgical methods (CWICKs or UPPP). On the other hand, an association was shown with age (<45), palatine tonsil size (≥3 / 5), high MPH (≥14 mm), and OAI rate (> 1/3). ConclusionThe treatment outcome of CWICKs was equal to or better than that of the conventional UPPP. Future follow-up is required for long-term prognosis, but no serious postoperative complications, such as dysphagia or scar stenosis, have been observed. CWICKs are considered to be minimally invasive, simple, and effective surgical procedures with few complications.

Awareness, attitude, and practice about basic life support among dental students

Introduction: A medical emergency can be described as a sudden onset of serious illness or injury requiring immediate medical attention otherwise it can put a patient's health in serious jeopardy, often referred to as a situation risking “life or limb.” It is thus imperative that dental students are competent enough to administer basic life support (BLS) to manage emergencies which can occur anywhere and anytime. Materials and Methods: A cross-sectional survey was conducted to assess the knowledge, attitude, and perception among dental students of Manav Rachna Dental College, Faridabad, about BLS. A total of 177 students participated in the study. The respondents were provided with a prevalidated, self-administered questionnaire which comprised 23 closed-ended questions about knowledge, three questions about attitude, and five questions about practice of BLS. The questionnaire was administered in an online mode using Google Forms. Results: The results showed that majority of students lacked adequate knowledge about BLS protocol. The average score of 177 respondents was 7.8/23 points which is significantly low. Discussion: Life-threatening medical emergencies can occur at any time. There have been reports of Cardiopulmonary Arrest (CPA) and deaths in dental clinics. Therefore, it is crucial for dental practitioners to have adequate knowledge about BLS or CAB consisting of (C) circulation, (B) breathing, and (A) airway opening. Conclusion: The dental students lack adequate knowledge to perform BLS procedures with ease and confidence. However, they had a positive attitude toward it.

Comparison of Volume Support, Volume-Assured Pressure Support, and Spontaneous Modes in Postoperative Early Extubated Patients.

This study aimed to compare respiratorily, arterial blood gas (ABG), and hemodynamics parameters among patients undergoing surgery who were admitted to intensive care unit (ICU), using three ventilation modes, including volume-assured pressure support (VAPS), volume support (VS), and spontaneous modes. One hundred and thirty-two patients were randomly assigned into three groups of VAPS, VS, and spontaneous modes utilizing randomized block procedure. Patients were followed between 12 and 30 h until extubation. Respiratory parameters including; peak inspiratory pressure (PIP), static compliance, resistance, rapid shallow breathing index (RSBI), and P 0.1(P0.1 correlates with respiratory drive and is defined as the negative pressure measured at the airway opening 100 ms after the initiation of an inspiratory effort), along with ABG parameters including; pH level, PaCO2,HCO3,PaO2/FiO2 ratio, extra hydrogen ion, and hemodynamics parameters including; mean arterial blood pressure and heart rate were measured every 3 h and compared among groups. All studied parameters in three groups improved during the study. PIP, Resistance, PH, HCO3, extra hydrogen ion, PCo2, PaO2/FiO2 ratio, mean arterial blood pressure were similar among the three groups in most of the time points (P > 0.05). In most of the time points, RSBI (from 92.7 to 55.4), P 0.1 (from 6.8 to 1.7) in the VAPS group, static compliance (from 55.3 to 55.7) in the VS group, and heart rate (from 108.5 to 90.1) in spontaneous groups were significantly better than other modes (P < 0.05). Changes in RSBI, P 0.1, PCo2, HCO3, and heart rate during the study were significantly different among studied groups (P < 0.05). The length of stay in the ICU in patients who underwent VAPS was significantly shorter than the other modes. VAPS mode with better effects or at least as effective as VS and spontaneous modes could be select as the best mode of ventilation in postoperative early extubated patients admitted to ICU.

Monitoring Expired CO2 Kinetics to Individualize Lung-Protective Ventilation in Patients With the Acute Respiratory Distress Syndrome.

Mechanical ventilation (MV) is a lifesaving supportive intervention in the management of acute respiratory distress syndrome (ARDS), buying time while the primary precipitating cause is being corrected. However, MV can contribute to a worsening of the primary lung injury, known as ventilation-induced lung injury (VILI), which could have an important impact on outcome. The ARDS lung is characterized by diffuse and heterogeneous lung damage and is particularly prone to suffer the consequences of an excessive mechanical stress imposed by higher airway pressures and volumes during MV. Of major concern is cyclic overdistension, affecting those lung segments receiving a proportionally higher tidal volume in an overall reduced lung volume. Theoretically, healthier lung regions are submitted to a larger stress and cyclic deformation and thus at high risk for developing VILI. Clinicians have difficulties in detecting VILI, particularly cyclic overdistension at the bedside, since routine monitoring of gas exchange and lung mechanics are relatively insensitive to this mechanism of VILI. Expired CO2 kinetics integrates relevant pathophysiological information of high interest for monitoring. CO2 is produced by cell metabolism in large daily quantities. After diffusing to tissue capillaries, CO2 is transported first by the venous and then by pulmonary circulation to the lung. Thereafter diffusing from capillaries to lung alveoli, it is finally convectively transported by lung ventilation for its elimination to the atmosphere. Modern readily clinically available sensor technology integrates information related to pulmonary ventilation, perfusion, and gas exchange from the single analysis of expired CO2 kinetics measured at the airway opening. Current volumetric capnography (VCap), the representation of the volume of expired CO2 in one single breath, informs about pulmonary perfusion, end-expiratory lung volume, dead space, and pulmonary ventilation inhomogeneities, all intimately related to cyclic overdistension during MV. Additionally, the recently described capnodynamic method provides the possibility to continuously measure the end-expiratory lung volume and effective pulmonary blood flow. All this information is accessed non-invasively and breath-by-breath helping clinicians to personalize ventilatory settings at the bedside and minimize overdistension and cyclic deformation of lung tissue.

This Month in Anesthesiology

This Month in Anesthesiology

Assessment of Respiratory System Resistance during High-Frequency Oscillatory Ventilation Based on In Vitro Experiment

High-frequency oscillatory ventilation (HFOV) is a type of mechanical ventilation with a protective potential characterized by a small tidal volume. Unfortunately, HFOV has limited monitoring of ventilation parameters and mechanical parameters of the respiratory system, which makes it difficult to adjust the continuous distension pressure (CDP) according to the individual patient’s airway status. Airway resistance Raw is one of the important parameters describing the mechanics of the respiratory system. The aim of the presented study was to verify in vitro whether the resistance of the respiratory system Rrs can be reliably determined during HFOV to evaluate Raw in pediatric and adult patients. An experiment was performed with a 3100B high-frequency oscillator, a physical model of the respiratory system, and a pressure and flow measurement system. The physical model with different combinations of resistance and compliance was ventilated during the experiment. The resistance Rrs was calculated from the impedance of the physical model, which was determined from the spectral density of the pressure at airway opening and the spectral cross-density of the gas flow and pressure at airway opening. Rrs of the model increased with an added resistor and did not change significantly with a change in compliance. The method is feasible for monitoring respiratory system resistance during HFOV and has the potential to optimize CDP settings during HFOV in clinical practice.

Abstract 13027: Investigating the Airway Opening Index During Cardiopulmonary Resuscitation

Introduction: In 40-70% of out-of-hospital cardiac arrest (OHCA) cases, chest compressions (CCs) during CPR induce measurable oscillations in capnography (E T CO 2 ). Recent studies suggest the magnitude and frequency of oscillations are due to intrathoracic airflow dependent on airway patency. These oscillations can be quantified by the Airway Opening Index (AOI), ranging from 0-100%. We sought to develop, automate, and evaluate multiple methods of computing AOI throughout CPR. Methods: We conducted a retrospective study of all OHCA cases in Seattle, WA during 2019. E T CO 2 and impedance waveforms from LifePak 15 defibrillators were annotated for the presence of intubation and CPR, and imported into MATLAB for analysis. Four proposed methods for computing AOI were developed (Fig. 1) using peak E T CO 2 in conjunction with ΔE T CO 2 (oscillations in E T CO 2 from CCs). We examined the feasibility of automating ΔE T CO 2 and AOI calculation during CCs throughout OHCA resuscitation and evaluated differences in mean AOI using each method. Statistical significance was assessed with ANOVA (alpha = 0.05). Results: AOI was measurable in 312 of 465 cases. Mean [95% confidence interval] AOI across all cases was 34.3% [32.0-36.5%] for method 1, 27.6% [25.5-29.7%] for method 2, 22.7% [21.1-24.3%] for method 3, and 28.8% [26.6-31.0%] for method 4. Mean AOI was significantly different across the four methods (p&lt;0.001), with the greatest difference between method 1 and 3 (11.6%, p&lt;0.001), but no significant difference between methods 2 and 4 (p=0.44). Mean ΔE T CO 2 was 7.76 [7.08-8.44] mmHg. Conclusion: We implemented four proposed methods of automatically calculating AOI during OHCA. Each method produced a different average AOI. Consistent, automated methods to measure AOI provide the foundation to evaluate if, and how, AOI may change with treatment or predict outcomes. These four approaches require additional investigation to understand which may be best suited to improve OHCA care.

Voice outcomes and its impact on quality of life after open airway surgery in children

IntroductionOpen airway surgery is used to treat severe grades of laryngotracheal stenosis in children. Scarring of the airway following these procedures may lead to voice impairment and impact quality of life. This study was designed to characterize vocal outcome in children submitted reconstructive airway surgery and verify how this correlates to voice related quality of life in this population. Material and methodsChildren submitted to open airway surgery that had been decannulated for a minimum of 30 days and had functional speech were invited to participate. Pediatric Voice-Related Quality-of-Life survey (PVRQoL) was applied, consensus auditory perceptive of voice (CAPE-V) protocol was used for perceptual voice evaluation and acoustic analysis was performed using Praat software. ResultsTwenty children were enrolled in the study with an average age of 4 years and 8 months. Averages for PVRQoL exceeded normative values in 80% of the children. Half of the children had normal voice or mild dysphonia and half had moderate dysphonia, according to perceptual evaluation. Measures of F0, jitter and particularly shimmer were abnormal in most of the children. ConclusionVoice quality varies from normal to moderately impaired in children following reconstructive airway surgery. Voice quality impacts quality of life in the majority of cases and the degree of dysphonia does not always correlate with voice related quality of life scores.

Impact of lung structure on airway opening index during mechanical versus manual chest compressions in a porcine model of cardiac arrest

ObjectivesThe exhaled CO2 signal provides guidance during cardiopulmonary resuscitation. The Airway opening index (AOI) has been recently used to quantify chest-compression (CC) induced expired CO2 oscillations. We aimed to determine whether levels of intrathoracic pressures developed during CC or parameters related to lung structure may affect AOI. MethodsSecondary analysis of a randomized animal study (n = 12) in a porcine model of cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) during ambulance transport. Animals were randomized to 18-min of manual or mechanical CCs. Changes in AOI and right atrial pressure (ΔRAP) were recorded during CCs in animals undergoing manual (n = 6) or mechanical (n = 6) CCs. Lung CT scan and measurement of the respiratory system compliance (Cpl,rs) were performed immediately after return of spontaneous circulation. ResultsAnimals undergoing mechanical CCs had a lower AOI compared to animals treated with manual CCs (p < 0.001). AOI negatively correlated with the swings of intrathoracic pressure, as measured by the change in ΔRAP (ρ=−0.727, p = 0.007). AOI correlated with the lung density (ρ=−0.818, p = 0.001) and with the Cpl,rs (ρ = 0.676, p = 0.016). Animals with cardiopulmonary resuscitation associated lung edema (CRALE) (i.e. mean CT≥−500 HU) showed lower levels of AOI compared to animals without it (29 ± 12 % versus 50 ± 16 %, p = 0.025). ConclusionsAnimals undergoing mechanical CCs had lower levels of AOI compared to animals undergoing manual CCs. A higher swing of intrathoracic pressure during CC, a denser and a stiffer lung were associated with an impaired CO2 exhalation during CC as observed by a lower AOI.

Hybrid laryngotracheal reconstruction vs single and double stage: Indications and outcomes

ObjectivesTo describe outcomes from laryngotracheal reconstruction and decannulation rates for patients undergoing single stage, double stage and hybrid staged procedures at a single tertiary care institution and evaluate if the 1.5LTR is a viable reconstructive option for patients with subglottic stenosis. Study designRetrospective chart review. SettingTertiary care otolaryngology specialty hospital and internationally. SubjectsAll patients who underwent LTR by a single pediatric otolaryngology surgeon from 2008 to 2018. MethodsCharts were assessed for age, gender, etiology, type of reconstruction, comorbidities, length of stay, tracheostomy status and socioeconomic status. Analysis was performed using Microsoft Excel and multivariate logistic regression models. Results96 patients underwent laryngotracheal reconstruction at MEEI. Internationally, 36 patients underwent laryngotracheal reconstruction with the primary surgeon. Overall decannulation rates for ssLTR, dsLTR, and 1.5LTR were 95.6%, 77.8%, and 91.2% respectively. Our Operation Specific Decannulation Rates (one open airway procedure only) for ssLTR, dsLTR, and 1.5LTR were 87.5%, 33%, and 88% respectively. Adjusted odds of decannulation were not significantly different between males and females, white and non-white patients, or socioeconomic status. Neurological comorbidity was statistically significant for a decreased rate of decannulation (p = 0.0216). ConclusionThe 1.5LTR is a viable option for airway reconstruction with strengths derived from both the ssLTR and dsLTR. At our institution we have seen decannulation rates and operation specific decannulation rates with the 1.5LTR approaching our ssLTR. It has replaced the bulk of our dsLTRs, which we reserve for patients that have significant neurological deficits and cannot tolerate extended sedation. Level of evidence4

Performance of Different Low-Flow Oxygen Delivery Systems.

The delivery of a high and consistent [Formula: see text] is imperative to treat acute hypoxemia. The objective of this study was to analyze the effective inspired oxygen concentration delivered by different low-flow oxygen therapy systems challenged with different oxygen flows and respiratory patterns in an experimental lung model. An adult lung model ventilated in volume control mode simulated different respiratory patterns to obtain mean inspiratory flow of 22.5, 30.0, 37.5, or 45.0 L/min. The oxygen concentration sampled inside the lung model by nasal cannula, simple face mask, non-rebreather mask, and double-trunk mask above nasal cannula tested at oxygen flows of 10, 12.5, and 15 L/min was quantified. The 3 masks were sealed tight onto the model's airway opening. They were also tested with standardized leaks to determine their clinical performance. All oxygen delivery systems delivered higher oxygen concentration with increasing oxygen flows, regardless of the respiratory pattern. Within each device, the increase in inspiratory flow decreased oxygen concentration when using nasal cannula (P = .03), the simple face mask (P = .03), but not the non-rebreather mask (P = .051) nor the double-trunk mask (P = .13). In sealed condition, the double-trunk mask outperformed the non-rebreather mask and simple face mask (P < .001); mean oxygen concentration was 84.2%, 68.5%, and 60.8%, respectively. Leaks amplified oxygen concentration differences between the double-trunk mask and the other masks as the oxygen delivery decreased by 4.6% with simple face mask (95% CI 3.1-6.1%, P < .001), 7.8% with non-rebreather mask (95% CI 6.3-9.3%, P < .001), and 2.5% with double-trunk mask (95% CI 1-4%, P = .002). With leaks, the oxygen concentration provided by the simple face mask and the non-rebreather mask was similar (P = .15). Lung oxygen concentration values delivered by the double-trunk mask were higher than those obtained with other oxygen delivery systems, especially when leaks were present.

Analysis of remaining motion using one innovative upper airway opening cervical collar and two traditional cervical collars

The aim of this study was to compare the remaining motion of an immobilized cervical spine using an innovative cervical collar as well as two traditional cervical collars. The study was performed on eight fresh human cadavers. The cervical spine was immobilized with one innovative (Lubo Airway Collar) and two traditional cervical collars (Stifneck and Perfit ACE). The flexion and lateral bending of the cervical spine were measured using a wireless motion tracker (Xsens). With the Weinman Lubo Airway Collar attached, the mean remaining flexion was 20.0 ± 9.0°. The mean remaining flexion was lowest with the Laerdal Stifneck (13.1 ± 6.6°) or Ambu Perfit ACE (10.8 ± 5.8°) applied. Compared to that of the innovative Weinmann Lubo Airway Collar, the remaining cervical spine flexion was significantly decreased with the Ambu Perfit ACE. There was no significant difference in lateral bending between the three examined collars. The most effective immobilization of the cervical spine was achieved when traditional cervical collars were implemented. However, all tested cervical collars showed remaining motion of the cervical spine. Thus, alternative immobilization techniques should be considered.

Review on Theobromine: An Alternative to Fluorides in Treating Dentinal Hypersensitivity

Theobromine is a unique constituent that can help dentistry and general health in the future. The generic name of theobroma is obtained from two Greek words i.e., Theo and Broma, which means “food of the gods". It can be found in cocoa beans and chocolates. Theodent toothpaste harness the power of cocoa. Rennou, the main component in Theodent, is a unique compound that combines theobromine, calcium, and phosphate to enhance enamel remineralization. This article is to review the effectiveness of theobromine in blocking dentinal tubules by preventing dentinal hypersensitivity, and its positive effects on general health. Various researches and valid documents were reviewed by us. Several studies have been conducted that shows theobromine is effective in blocking dentinal tubules, thus preventing dentinal hypersensitivity as well as tooth demineralization. It also has other general health benefits. Because of its potent vasodilation, diuretic and heart stimulant effect, theobromine can also be used in treating high blood pressure. It also aids in opening of airways and helps in preventing kidney stones. The use of fluoride dentifrices is debatable, as it has many detrimental effects. Also, we consider that theobromine if used as a component in dentifrices, if unintentionally swallowed, cause no catastrophic effects.

Empirical evidence for safety of mechanical ventilation during simulated cardiopulmonary resuscitation on a physical model.

Cardiac arrest is a critical event requiring adequate and timely response in order to increase a patient's chance of survival. In patients mechanically ventilated with advanced airways, cardiopulmonary resuscitation (CPR) maneuver may be simplified by keeping the ventilator on. This work assessed the response of an intensive care mechanical ventilator to CPR using a patient manikin ventilated in three conventional modes. Volume-controlled (VCV), pressure-controlled (PCV) and pressure regulated volume-controlled (PRVC) ventilation were applied in a thorax physical model, with or without chest compressions. The mechanical ventilator was set with inspiratory time of 1.0 s, ventilation rate of 10 breaths/min, positive end-expiratory pressure of 0 cmH2O, FiO2 of 1.0, target tidal volume of 600 mL and trigger level of -20 cmH2O. Airway opening pressure and ventilatory flow signals were continuously recorded. Chest compression resulted in increased airway peak pressure in all ventilation modes (p < 0.001), especially with VCV (137% in VCV, 83% in PCV, 80% in PRVC). However, these pressures were limited to levels similar to release valves in manual resuscitators (~60 cmH2O). In pressure-controlled modes tidal/min volumes decreased (PRVC = 11%, p = 0.027 and PCV = 12%, p < 0.001), while still within the variability observed during bag-valve-mask ventilation. During VCV, variation in tidal/min volumes were not significant (p = 0.140). Respiratory rate did not change with chest compression. Volume and pressure ventilation modes responded differently to chest compressions. Yet, variation in delivered volume and the measured peak pressures were within the reported for the standard bag-valve-mask system.

Changes of lung microbiome of acute respiratory distress syndrome before and after treatment under open airway

To analyze the differences and similarities of pre-treatment and post-treatment lung microbiome of acute respiratory distress syndrome (ARDS) and find out the change rules of the lung microbiome in the progression of ARDS according to different prognosis. A retrospective study was conducted. Patients with ARDS caused by severe pneumonia admitted to intensive care unit (ICU) of Jiangmen Central Hospital from February 2019 to January 2020 were enrolled as the study subjects. The patients were divided into pre-treatment (ARDS-preT) group (24 cases), post-treatment survival (ARDS-poT-Survival) group (17 cases), and post-treatment death (ARDS-poT-Dead) group (7 cases). ICU patients with mild pulmonary infection and non-ARDS admitted to ICU during the same period were enrolled as control group (25 cases). The similarities and differences of lung microbiome in four groups were analyzed and compared, and the possible pathogenic bacteria (potential risk factors for death) and probiotics (potential survival and protective factors) related to death caused by ARDS were screened. In terms of pathogenic microorganisms, the positive rates of Escherichia coli and Candida albicans in the ARDS-poT-Dead group were significantly higher than those in the ARDS-poT-Survival group [57.1% (4/7) vs. 5.9% (1/17) and 57.1% (4/7) vs. 0% (0/7), both P < 0.05]. In the screening of background bacteria, the decrease of bacteria in the ARDS-preT group compared with the ARDS-poT-Survival group, the ARDS-poT-Dead group compared with the ARDS-poT-Survival group, the ARDS-poT-Dead group compared with the control group, the reduced bacteria might be pulmonary probiotics (potential protective factor for ARDS). The screening result was Hydrobacter [ARDS-preT group vs. ARDS-poT-Survival group: 62.5% (15/24) vs. 94.1% (16/17); ARDS-poT-Dead group vs. ARDS-poT-Survival group: 14.3% (1/7) vs. 94.1% (16/17); ARDS-poT-Dead vs. control: 14.3% (1/7) vs. 96.0% (24/25), all P < 0.05]. In the screening of background bacteria, the increase of bacteria in the ARDS-poT-Dead group compared with the ARDS-preT group, the ARDS-poT-Dead group compared with the ARDS-poT-Survival group, the ARDS-poT-Dead group compared with the control group, and the increased bacteria might be potential pulmonary pathogen (potential risk factor for death of ARDS), which belonged to Enterobacteria: Edwardsiella, Enterobacteriaceae, Escherichia, Klebsiella, Kluyvera, Lelliottia, Pantoea, Raoultella. The results revealed the increase of Escherichia coli or Candida albicans in pulmonary pathogenic microorganisms, or the increase of Enterobacteria in background bacteria may be the risk factors for the death of ARDS. Additionally, background bacteria Hydrobacter probably is a protective factor for the survival of ARDS. Whether it can be used as a novel treatment for ARDS is worth further investigation.

A computational model of upper airway respiratory function with muscular coupling

A two dimensional finite element model of upper airway respiratory function was developed emphasizing the effects of dilator muscular activation on the human retro-lingual airway. The model utilized an upright mid-sagittal computed tomography of the human head and neck to reconstruct relevant structures of the tongue, mandible, and the hyoid-related soft tissues, along with the retro-lingual airway. The reconstructed geometry was divided into fluid and solid domains and discretized into finite element (FE) meshes used for the computational model. Three cases were investigated: standing position; supine position; and supine position coupled with dilator muscle activation. Computations were performed for the inspiration stage of the breathing cycle, utilizing a fluid-structure interaction (FSI) method to couple structural deformation with airflow dynamics. The spatio-temporal deformation of the structures surrounding the airway wall were predicted to be in general agreement with known changes from upright to supine posture on luminal opening, as well as the distribution of airflow. The model effectively captured the effects of muscular stimulation on the upper airway anatomical changes, the flow characteristics relevant to airway reduction in the supine position and airway enlargement with muscle activation. The smallest airway opening in the retro-lingual section is predicted to occur at the epiglottic region in all the three cases considered, an unexpected vulnerable location of airway obstruction. The model also predicted that hyoid displacement would be associated with recovery from airway collapse. This information may be useful for building more complex models relevant to mechanisms and clinical interventions for obstructive sleep apnea.

Treatment outcomes in patients with laryngotracheal lesions and compromised airway during and prior to the coronovirus disease 2019 pandemic: a tertiary institution's experience.

This study aimed to compare treatment outcomes in patients with laryngeal and tracheal stenosis treated during and prior to the coronavirus disease 2019 pandemic period. Patients treated for laryngotracheal lesions with impending airway compromise during the active pandemic period were matched with those treated for similar lesions in the preceding years in a monocentric tertiary hospital setting. During the pandemic period of 55 days, 31 patients underwent 47 procedures. Seven patients (2 children, 5 adults) had open airway surgery, and one had an operation-specific complication. Twenty-four patients (10 children, 14 adults) underwent 40 endoscopic interventions without any complications. Operation specific results during and prior to the pandemic were comparable. The management strategy in patients with laryngotracheal lesions and impending airway compromise should not be altered during periods of risk from coronavirus disease 2019. Avoiding a tracheostomy by performing primary corrective surgery or proceeding with a definitive decannulation would be beneficial in these patients to reduce the risk of contagion.

Airway Anesthesia for Awake Tracheal Intubation: A Review of the Literature.

Airway topicalization is frequently utilized by anesthesiologists to facilitate open airway procedures, aid intubation for a difficult airway, and prevent adverse respiratory events. This review article summarizes the techniques available for airway topicalization for a patient who is deemed to be difficult to intubate. We focus on the indications for use, local anesthetic maximum dosages and safety profiles, sedation techniques, and trials and pitfalls during airway topicalization for difficult intubation.

Real-Time In Vitro Assessment of Aerosol Delivery During Mechanical Ventilation.

Background: A new real-time method for assessing factors determining aerosol delivery is described.Methods: A breath-enhanced jet nebulizer operated in a ventilator/heated humidifier system was tested during bolus and continuous infusion aerosol delivery. 99mTc (technetium)/saline was either injected (3 or 6 mL) or infused over time into the nebulizer. A shielded gamma ratemeter was oriented to count radioaerosol accumulating on an inhaled mass (IM) filter at the airway opening of a test lung. Radioactivity measured at 2–10-minute intervals was expressed as % nebulizer charge (bolus) or % syringe activity per minute infused. All circuit parts were measured and imaged by gamma camera to determine mass balance.Results: Ratemeter activity quantitatively reflected immediate changes in IM: 3 and 6 mL bolus IM% = 16.1 and 18.8% in 6 and 14 minutes, respectively; infusion IM% = 0.64 + 0.13 (run time, min), R2 0.999. Effect of nebulizer priming and system anomalies were readily detected in real time. Mass balance (basis = dose infused in 90 minutes): IM 39.2%, breath-enhanced jet nebulizer residual 35.5%, circuit parts including humidifier 23.4%, and total recovery 98.1%. Visual analysis of circuit component images identified sites of increased deposition.Conclusion: Real-time ratemeter measurement with gamma camera imaging provides operational feedback during in vitro testing procedures and yields a detailed analysis of the parameters influencing drug delivery during mechanical ventilation. This method of analysis facilitates assessment of device function and influence of circuit parameters on drug delivery.