Endotracheal Tube Surface Research Articles

Endotracheal tubes with dexamethasone eluting electrospun coating improve tissue mechanical function after upper airway injury

Corticosteroid-eluting endotracheal tubes (ETTs) were developed and employed in a swine laryngotracheal injury model to maintain airway patency and provide localized drug delivery to inhibit fibrotic scarring. Polycaprolactone (PCL) fibers with or without dexamethasone were electrospun onto the ETT surface PCL-only coated ETTs and placed in native airways of 18 Yorkshire swine. Regular and dexamethasone-PCL coated ETTs were placed in airways of another 18 swine injured by inner laryngeal mucosal abrasion. All groups were evaluated after 3, 7 and 14 days (n = 3/treatment/time). Larynges were bisected and localized stiffness determined by normal indentation, then sequentially matched with histological assessment. In the native airway, tissue stiffness with PCL-only ETT placement increased significantly from 3 to 7 days (p = 0.0016) and 3 to 14 days (p < 0.0001) while dexamethasone-PCL ETT placement resulted in stiffness decreasing from 7 to 14 days (p = 0.031). In the injured airway, localized stiffness at 14 days was significantly greater after regular ETT placement (23.1 ± 0.725 N/m) versus dexamethasone-PCL ETTs (17.10 ± 0.930 N/m, p < 0.0001). Dexamethasone-loaded ETTs were found to reduce laryngotracheal tissue stiffening after simulated intubation injury compared to regular ETTs, supported by a trend of reduced collagen in the basement membrane in injured swine over time. Findings suggest localized corticosteroid delivery allows for tissue stiffness control and potential use as an approach for prevention and treatment of scarring caused by intubation injury.

Epithelial lining inspired protective shield for prolonged endotracheal intubation

Endotracheal intubation often suffers from side effects due to inherent defects of the endotracheal tube (ETT) itself, posing a formidable challenge for minimally invasive medical interventions. Inspired by biological functions of the epithelial lining, a novel concept of a protective shield is proposed and engineered onto the surface of commercially-available ETTs via a gas-phase fluorination technology. The direct gas-solid reaction enables fluorinated decoration adaptively to both outer and inner surfaces of ETTs for all-round protection. The protective shield composed by the fluorinated coating not only shows high stability to harsh conditions, excellent hydrophilic lubrication, and good biocompatibility, but also exhibits a favorable anti-biofouling property to a broad spectrum of biofoulings and strong antimicrobial activity against Klebsiella pneumoniae. Crediting the above merits, in vivo experiments affirm that the ETT with the protective shield is efficacious to migrate intubation-related complications in two aspects: reducing mucosal injury and inflammation caused by the outer surface friction, and preventing biofilm formation and airway obstruction to maintain inner tube patency. This work opens an avenue for updating EETs to meet clinic needs and holds promise towards the development of invasive biomedical devices.

Antibiotic Susceptibility Pattern of the Potential Pathogens of Ventilator Associated Pneumonia in the Endotracheal Tubes of Critically Ill Patients

An endotracheal (ET) tube offers surface for potential pathogens to attach and produce biofilm. These potential pathogens are typically hospital flora with a broad range of antibiotic resistance. The study aimed to characterize the biofilm-producing flora in ET tube of critically ill patients. Following extubation, ET tubes were retrieved aseptically from 100 different patients and promptly transported in a sterile ziplock bag. Each ET tube was cut into three different sections; inner lumen was scraped out and inoculated on Blood agar, MacConkey agar, and Chocolate agar. Colonies produced on media were tested for antibiotic susceptibility testing by applying disc diffusion and Colistin minimum inhibitory concentration (MIC). Out of 100 ET tubes, monomicrobial growth was observed in 62, polymicrobial growth in 14, and no growth in 24 specimens. A total of 93 potential pathogens were isolated including 25 (26.89%) Acinetobacter species, 23 (24.73%) Klebsiella species, 15(16.12%) Pseudomonas species, 13 (13.98%) E. coli, 6 (6.45%), Staphylococcus aureus, 4 (4.3%) Coagulase Negative Staphylococcus species (CoNS), 2 (2.15%) Proteus species, 1 (1.07%) Enterobacter species and 4 (4.3%) Candida species. Imipenem and Colistin proved to be among the most successful antibiotics against gram negative isolates. Only 1 out of 25 Acinetobacter species was resistant to Colistin. Methicillin resistance emerged in two S. aureus and three CoNS strains. Microorganisms usually adhere themselves to the surface of ET tubes. They may act as potential pathogens for the onset of Ventilator Associated Pneumonia (VAP) and are resistant to commonly administered antibiotics in hospitals. A technique to reduce or prevent the risk of biofilm development is crucial.

Antimicrobial materials for endotracheal tubes: A review on the last two decades of technological progress.

Ventilator-associated pneumonia (VAP) is an unresolved problem in nosocomial settings, remaining consistently associated with a lack of treatment, high mortality, and prolonged hospital stay. The endotracheal tube (ETT) is the major culprit for VAP development owing to its early surface microbial colonization and biofilm formation by multiple pathogens, both critical events for VAP pathogenesis and relapses. To combat this matter, gradual research on antimicrobial ETT surface coating/modification approaches has been made. This review provides an overview of the relevance and implications of the ETT bioburden for VAP pathogenesis and how technological research on antimicrobial materials for ETTs has evolved. Firstly, certain main VAP attributes (definition/categorization; outcomes; economic impact) were outlined, highlighting the issues in defining/diagnosing VAP that often difficult VAP early- and late-onset differentiation, and that generate misinterpretations in VAP surveillance and discrepant outcomes. The central role of the ETT microbial colonization and subsequent biofilm formation as fundamental contributors to VAP pathogenesis was then underscored, in parallel with the uncovering of the polymicrobial ecosystem of VAP-related infections. Secondly, the latest technological developments (reported since 2002) on materials able to endow the ETT surface with active antimicrobial and/or passive antifouling properties were annotated, being further subject to critical scrutiny concerning their potentialities and/or constraints in reducing ETT bioburden and the risk of VAP while retaining/improving the safety of use. Taking those gaps/challenges into consideration, we discussed potential avenues that may assist upcoming advances in the field to tackle VAP rampant rates and improve patient care. STATEMENT OF SIGNIFICANCE: The use of the endotracheal tube (ETT) in patients requiring mechanical ventilation is associated with the development of ventilator-associated pneumonia (VAP). Its rapid surface colonization and biofilm formation are critical events for VAP pathogenesis and relapses. This review provides a comprehensive overview on the relevance/implications of the ETT biofilm in VAP, and on how research on antimicrobial ETT surface coating/modification technology has evolved over the last two decades. Despite significant technological advances, the limited number of gathered reports (46), highlights difficulty in overcoming certain hurdles associated with VAP (e.g., persistent colonization/biofilm formation; mechanical ventilation duration; hospital length of stay; VAP occurrence), which makes this an evolving, complex, and challenging matter. Challenges and opportunities in the field are discussed.

Macromolecular Coatings for Endotracheal Tubes Probed on An Ex Vivo Extubation Setup

AbstractEndotracheal intubation is indispensable in modern healthcare but typically entails two complications for the treated patients: biofouling‐induced infections and friction‐associated damage to the tissue. Coatings on the endotracheal tubes (ETT) may mitigate those problems, but they require a well‐defined testing method to assess their functionality. Here, such a testing setup is presented, which allows for conducting ex vivo extubation experiments in a reproducible manner. With this setup, different coating strategies that immobilize porcine gastric mucins on the ETT surface are compared. The results demonstrate that covalent coatings generated from lab‐purified mucins outperform the other variants in terms of their ability to decrease tissue damage, prevent lipid adsorption, and reduce cell attachment. With a similar approach as presented here, it should also be possible to evaluate macromolecular coatings generated on other medical tubing systems such as cardiac and urinary catheters and endoscopes.

Comparison of Needle Electrode and Endotracheal Tube Surface Electrode for Intraoperative Neuromonitoring During Thyroid and Parathyroid Surgery

Öz: &#x0D; Amaç: Yüzey elektrotlu endotrakeal tüp kullanılarak yapılan intraoperatif nöromonitörizasyon güvenli ve basit olması sebebiyle günümüzde en yaygın kullanılan teknik haline gelmiştir. Yüzey elektrotlu endotrakeal tüp ile intraoperatif nöromonitörizasyonun, yanlış pozitif sinyal kaybı gibi bazı dezavantajları vardır. Bu nedenle, tiroid kıkırdağına yerleştirilen elektrotlar, tiroaritenoid kasın ve RLS' nin fonksiyonunu değerlendirmek için alternatif bir araçtır. Bu çalışmanın amacı, tiroid ve paratiroid cerrahisinde uygulanan aralıklı intraoperatif nöromonitörizasyon esnasında tiroid kıkırdak iğne elektrotları ve standart endotrakeal tüp yüzey elektrotları beraber kullanılarak eşzamanlı olarak kaydedilen EMG sinyallerinin değerlendirilmesi ve karşılaştırılmasıdır.&#x0D; Gereç ve Yöntem: Bu çalışmada tek merkezde, aralıklı intraoperatif nöromonitörizasyon sisteminin kayıt tarafı olarak hem tiroid kıkırdak iğne elektrotları hem de endotrakeal tüp yüzey elektrotları birlikte kullanılıp eş zamanlı olarak EMG sinyali kaydedilen ilk 21 tiroid ve paratiroid ameliyatının verileri retrospektif olarak analiz edilmiştir.&#x0D; Bulgular: Genel olarak, hem sağ hem de sol tarafta tiroid kıkırdak iğne elektrotlarından kaydedilen EMG genlikleri, her adımda (V1-R1-R2-V2) endotrakeal tüp yüzey elektrotlarından kaydedilenlerden belirgin olarak daha yüksek olarak saptanmıştır (tüm uyarı basamaklarında p

Comparison of needle electrode and endotracheal tube surface electrode for intraoperative neuromonitoring during thyroid and parathyroid surgery

Comparison of needle electrode and endotracheal tube surface electrode for intraoperative neuromonitoring during thyroid and parathyroid surgery

The use of thyroid cartilage needle electrodes in intraoperative neuromonitoring during thyroidectomy: Case-control study.

The most commonly used recording-side method in intraoperative neural monitoring (IONM) detects the stimulus with the endotracheal tube surface (ETS) electrodes placed in the endotracheal tube during thyroidectomy. The thyroid cartilage needle (TCN) electrode method is an alternative recording-side system in IONM. This study compared two recording-side techniques in IONM. Data were retrospectively analyzed from 885 patients who underwent thyroidectomy between January 2012 and December 2020, with 110 ETS and 775 TCN electrodes. Patients' demographics, diagnosis, surgery type, and amplitudes of all stimulation steps were compared. Costs per patient were calculated. No significant differences were found in the demographic data between the two groups. All amplitudes were higher in the IONM system where TCN electrodes were used than that with ETS electrodes (all stimulation steps p < 0.001, except left-V2 p=0.007). Further, TCN electrodes were 20 times cheaper than the ETS electrodes. TCN electrodes are an inexpensive and efficient alternative to ETS electrodes in IONM.

Effect of subinhibitory antibiotics concentrations on biofilm formation by clinical Acinetobacter baumannii isolated from endotracheal tubes in ventilator-associated pneumonia

The treatment of ventilator-associated pneumonia caused by Acinetobacter baumanii requires a probabilistic antibiotic therapy followed by a specific antibiotic therapy. However, this treatment is faced with two problems; first, the great ability of A. bauamnii to form a biofilm on the surface of endotra-cheal tube, and second the exposure of bacteria to a sub-minimal inhibitory concentration (Sub-MIC) of antibiotics due to their weak diffusion through the tissues. The purpose of the present study was to determine the effects of Sub-MICs of ceftazidime (CAZ), piperacillin/tazobactam (PIP/TAZ), imipenem (IMP) and colistin (CST) on biofilm formation of six A. baumanii clinical iso-lates and as well as on its representative strain ATCC 19606. Sub-MIC of ceftazidime was found to increase biofilm formation in all six isolates. Alt-hough, in the presence of Sub-MIC of PIP/TAZ, biofilm formation of three isolates was reduced. Also, Sub-MIC of CST had a stimulating effect on bio-film formation in three isolates and a reducing effect on one single isolate. While, no impact was noted on all isolates in the presence of Sub-MIC of IMP. The ATCC 19606 biofilm formation exhibited no significant change in the presence of Sub-MIC of IMP. However, it decreased in the presence of Sub-MIC of PIP / TAZ and CST and increased in the presence of Sub-MIC of CAZ Finally, an inappropriate choice of antibiotic therapy, combined with a lower concentration can in some cases stimulate the potential of clinical A. baumanii strains to form a biofilm in ventilator-associated pneumonia (VAP).

Bacteriophage Cocktail-Mediated Inhibition of Pseudomonas aeruginosa Biofilm on Endotracheal Tube Surface.

Although different strategies to control biofilm formation on endotracheal tubes have been proposed, there are scarce scientific data on applying phages for both removing and preventing Pseudomonas aeruginosa biofilms on the device surface. Here, the anti-biofilm capacity of five bacteriophages was evaluated by a high content screening assay. We observed that biofilms were significantly reduced after phage treatment, especially in multidrug-resistant strains. Considering the anti-biofilm screens, two phages were selected as cocktail components, and the cocktail’s ability to prevent colonization of the endotracheal tube surface was tested in a dynamic biofilm model. Phage-coated tubes were challenged with different P. aeruginosa strains. The biofilm growth was monitored from 24 to 168 h by colony forming unit counting, metabolic activity assessment, and biofilm morphology observation. The phage cocktail promoted differences of bacterial colonization; nonetheless, the action was strain dependent. Phage cocktail coating did not promote substantial changes in metabolic activity. Scanning electron microscopy revealed a higher concentration of biofilm cells in control, while tower-like structures could be observed on phage cocktail-coated tubes. These results demonstrate that with the development of new coating strategies, phage therapy has potential in controlling the endotracheal tube-associated biofilm.

Tratamiento de la Neumonía Asociada a la Ventilación Mecánica: cofactor de mortalidad en pacientes COVID-19 positivos

La infección por Sars-CoV-2 produce diversos cuadros clínicos, que incluyen la infección asintomática, enfermedad leve del tracto respiratorio superior y neumonía viral grave con insuficiencia respiratoria e incluso la muerte. La necesidad de internación de los pacientes más comprometidos introduce una complicación adicional, que es el riesgo de adquirir una infección intrahospitalaria. Entre éstas, la neumonía asociada a la ventilación mecánica (NAV) es una de las más frecuentes en las Unidades de Cuidados Intensivos (UCI) y actualmente es una complicación en el cuadro clínico de pacientes COVID-19 positivos que necesitan asistencia de respiración mecánica. La prevención de la NAV es crucial para eliminar este cofactor de morbimortalidad, así como disminuir los costos asociados a la atención de salud (tiempo de internación, antibióticos, elementos descartables, etc.).&#x0D; La NAV ocurre en pacientes que son ventilados por un tubo endotraqueal o por traqueotomía, como respuesta del huésped a la invasión bacteriana. Los pacientes con ventilación mecánica están inconscientes y no hay eliminación de las secreciones en la orofaringe, generando un aumento de la flora oral normal. Los microorganismos colonizadores pasan a lo largo del tubo traqueal formando biofilms en la parte interna y externa del mismo particularmente en la región cercana al bulbo. Finalmente, estos microorganismos son capaces de alcanzar las vías aéreas distales superando la respuesta inmune del huésped y generando neumonía. La propuesta de este trabajo consiste en modificar la superficie de los tubos endotraqueales con agentes antimicrobianos que inhiban la adhesión y proliferación bacteriana actuando como coadyuvantes de los antibióticos administrados por vía sistémica.&#x0D; El objetivo general de este trabajo es contribuir a la prevención de la NAV por medio de la funcionalización de las superficies interna y externa del tubo endotraqueal empleado en la ventilación mecánica. La modificación se realiza mediante el depósito de una delgada película de hidrogeles biocompatibles y biodegradables cargados con agentes antimicrobianos convencionales (antibióticos) y no convencionales (nanopartículas de plata, AgNPs) para combatir la formación de los biofilms bacterianos que generan la NAV. Los hidrogeles proporcionan control espacial y temporal sobre la liberación de los agentes terapéuticos debido a su degradabilidad controlable y capacidad para proteger a los medicamentos lábiles, permitiendo, además, alcanzar concentraciones locales superiores a las obtenidas por administración sistémica. Para alcanzar los objetivos, se ha optimizado la síntesis de un hidrogel en base a polietilenglicol capaz de adherirse fuertemente a la superficie de cloruro de polivinilo del tubo endotraqueal. Se logró recubrir la superficie del tubo con el hidrogel, comprobándose una buena estabilidad mecánica tanto para el hidrogel deshidratado como para el mismo hidratado. Se analizaron diferentes rutas de incorporación de los agentes antimicrobianos, encontrándose que la más adecuada es el agregado de éstos al polímero precursor del hidrogel. Los hidrogeles modificados con AgNPs presentan características de adhesión y estabilidad similares a las de los hidrogeles sin modificar. Al momento de escribir este trabajo se están llevando cabo los experimentos tendientes a determinar la capacidad antimicrobiana de las superficies modificadas.

Selective digestive decontamination solution used as \u201clock therapy\u201d prevents and eradicates bacterial biofilm in an in vitro bench-top model

BackgroundMost preventing measures for reducing ventilator-associated pneumonia (VAP) are based mainly on the decolonization of the internal surface of the endotracheal tubes (ETTs). However, it has been demonstrated that bacterial biofilm can also be formed on the external surface of ETTs. Our objective was to test in vitro the efficacy of selective digestive decontamination solution (SDDs) onto ETT to prevent biofilm formation and eradicate preformed biofilms of three different microorganisms of VAP.MethodsWe used an in vitro model in which we applied, at the subglottic space of ETT, biofilms of either P. aeruginosa ATCC 15442, or E. coli ATCC 25922, or S. aureus ATCC 29213, and the SDDs at the same time (prophylaxis) or after 72 h of biofilm forming (treatment). ETT were incubated during 5 days with a regimen of 2 h-locks. ETT fragments were analyzed by sonication and confocal laser scanning microscopy to calculate the percentage reduction of cfu and viable cells, respectively.ResultsMedian (IQR) percentage reduction of live cells and cfu/ml counts after treatment were, respectively, 53.2% (39.4%—64.1%) and 100% (100%–100.0%) for P. aeruginosa, and 67.9% (46.7%–78.7%) and 100% (100%–100.0%) for E. coli. S. aureus presented a complete eradication by both methods. After prophylaxis, there were absence of live cells and cfu/ml counts for all microorganisms.ConclusionsSDDs used as “lock therapy” in the subglottic space is a promising prophylactic approach that could be used in combination with the oro-digestive decontamination procedure in the prevention of VAP.

Biofilm formation on three different endotracheal tubes: a prospective clinical trial

BackgroundBiofilm formation on endotracheal tubes (ETTs) is an early and frequent event in mechanically ventilated patients. The biofilm is believed to act as a reservoir for infecting microorganisms and thereby contribute to development and relapses of ventilator-associated pneumonia (VAP). Once a biofilm has formed on an ETT surface, it is difficult to eradicate. This clinical study aimed to compare biofilm formation on three widely used ETTs with different surface properties and to explore factors potentially predictive of biofilm formation.MethodsWe compared the grade of biofilm formation on ETTs made of uncoated polyvinyl chloride (PVC), silicone-coated PVC, and PVC coated with noble metals after > 24 h of mechanical ventilation in critically ill patients. The comparison was based on scanning electron microscopy of ETT surfaces, biofilm grading, surveillance and biofilm cultures, and occurrence of VAP.ResultsHigh-grade (score ≥ 7) biofilm formation on the ETTs was associated with development of VAP (OR 4.17 [95% CI 1.14–15.3], p = 0.031). Compared to uncoated PVC ETTs, the silicone-coated and noble-metal-coated PVC ETTs were independently associated with reduced high-grade biofilm formation (OR 0.18 [95% CI 0.06–0.59], p = 0.005, and OR 0.34 [95% CI 0.13–0.93], p = 0.036, respectively). No significant difference was observed between silicon-coated ETTs and noble-metal-coated ETTs (OR 0.54 [95% CI 0.17–1.65], p = 0.278). In 60% of the oropharyngeal cultures and 58% of the endotracheal cultures collected at intubation, the same microorganism was found in the ETT biofilm at extubation. In patients who developed VAP, the causative microbe remained in the biofilm in 56% of cases, despite appropriate antibiotic therapy. High-grade biofilm formation on ETTs was not predicted by either colonization with common VAP pathogens in surveillance cultures or duration of invasive ventilation.ConclusionHigh-grade biofilm formation on ETTs was associated with development of VAP. Compared to the uncoated PVC ETTs, the silicone-coated and noble-metal-coated PVC ETTs were independently associated with reduced high-grade biofilm formation. Further research on methods to prevent, monitor, and manage biofilm occurrence is needed.Trial registrationClinicalTrials.gov NCT02284438. Retrospectively registered on 21 October 2014.

Pseudomonas aeruginosa biofilm formation on endotracheal tubes requires multiple two-component systems

Introduction. Indwelling medical devices such as endotracheal tubes (ETTs), urinary catheters, vascular access devices, tracheostomies and feeding tubes are often associated with hospital-acquired infections. Bacterial biofilm formed on the ETTs in intubated patients is a significant risk factor associated with ventilator-associated pneumonia. Pseudomonas aeruginosa is one of the four frequently encountered bacteria responsible for causing pneumonia, and the biofilm formation on ETTs. However, understanding of biofilm formation on ETT and interventions to prevent biofilm remains lagging. The ability to sense and adapt to external cues contributes to their success. Thus, the biofilm formation is likely to be influenced by the two-component systems (TCSs) that are composed of a membrane-associated sensor kinase and an intracellular response regulator.Aim. This study aims to establish an in vitro method to analyse the P. aeruginosa biofilm formation on ETTs, and identify the TCSs that contribute to this process.Methodology. In total, 112 P. aeruginosa PA14 TCS mutants were tested for their ability to form biofilm on ETTs, their effect on quorum sensing (QS) and motility.Results. Out of 112 TCS mutants studied, 56 had altered biofilm biomass on ETTs. Although the biofilm formation on ETTs is QS-dependent, none of the 56 loci controlled quorum signal. Of these, 18 novel TCSs specific to ETT biofilm were identified, namely, AauS, AgtS, ColR, CopS, CprR, NasT, KdpD, ParS, PmrB, PprA, PvrS, RcsC, PA14_11120, PA14_32580, PA14_45880, PA14_49420, PA14_52240, PA14_70790. The set of 56 included the GacS network, TCS proteins involved in fimbriae synthesis, TCS proteins involved in antimicrobial peptide resistance, and surface-sensing. Additionally, several of the TCS-encoding genes involved in biofilm formation on ETTs were found to be linked to flagellum-dependent swimming motility.Conclusions. Our study established an in vitro method for studying P. aeruginosa biofilm formation on the ETT surfaces. We also identified novel ETT-specific TCSs that could serve as targets to prevent biofilm formation on indwelling devices frequently used in clinical settings.

Study of the effectiveness of using decamethoxin-based antiseptic compositions for treating endotracheal tubes in order to prevent the development of ventilator-associated pneumonia in intensive care patients

Annotation. The use of artificial lung ventilation in patients of intensive care unit often leads to airway contamination of conditionally pathogenic microorganisms and the development of ventilator-associated pneumonia. The clinical manifestations of ventilator-associated pneumonia can vary widely from mild to development of critical conditions accompanied by septic shock. This significantly worsens the patient's condition and prognosis for effective treatment. The paper presents the results of the study of the use of adhesive antiseptic compositions based on the domestic antiseptic drug decamethoxin in order to give antimicrobial properties to intubation tubes. An antibacterial adhesive was applied to the surface of segments of the endotracheal intubation tube, after which the samples were dried in a sterile box. The sensitivity of the microorganisms to the components of the antiseptic compositions was studied by the diameter of the growth retardation zone around the studied fragments of endotracheal intubation tubes placed in the thickness of the pre-seeded microorganism’s dense nutrient medium. The results were statistically analyzed using standard application package for biomedical research “STATISTICA 5.5”. It has been proved that adhesive film-forming compositions based on decamethoxin confer pronounced antimicrobial properties to endotracheal intubation tubes. The most susceptible to antimicrobial activity were gram-positive microorganisms of the genus Staphylococcus, and the most resistant were representatives of gram-negative bacteria of the genus Acinetobacter. The obtained research results allow us to predict the effectiveness of the use of adhesive hydrophilic and hydrophobic antiseptic compositions based on the domestic antiseptic decamethoxin to provide protective properties of the surface of endotracheal tubes, prevent the process of bacterial film formation and prevention of ventilator-associated patients.

Photodynamic Activity on Biofilm in Endotracheal Tubes of Patients Admitted to an Intensive Care Unit.

Ventilator-associated pneumonia (VAP) is an infection that arises after endotracheal intubation affecting patients under intensive care. The presence of the endotracheal tube (ETT) is a risk factor since it is colonized by multispecies biofilm. Antimicrobial photodynamic therapy (aPDT) could be a strategy to decontaminate ETTs. We verify if methylene blue (MB) associated with external illumination of the ETT could be an alternative to destroy biofilm. We performed an in vitro and ex vivo study. In vitro study was performed with P. aeruginosa biofilm grew over ETT for 7days. After treatment, the surviving cells were cultured for 3days and the biofilm was analyzed by crystal violet absorbance. Ex vivo study employed ETT obtained from extubated patients. aPDT was performed with MB (100µm) and red LED (λ=640±20nm). We quantified the biofilm thickness and used scanning electron microscopy and fluorescence technique to verify morphological and functional changes after aPDT. Our results showed that bacteria remain susceptible to aPDT after sequential treatments. We also attested that aPDT can reduce biofilm thickness, disrupt biofilm attachment from ETT surface and kill microbial cells. These data suggest that aPDT should be investigated to decrease VAP incidence via ETT decontamination.

Neuromonitored Thyroid Surgery: Optimal Stimulation Based on Intraoperative EMG Response Features.

To evaluate/compare normative electrophysiologic electromyography (EMG) response characteristics of recurrent laryngeal, vagus, and external branch of superior laryngeal nerve evoked with different stimulators used in neuromonitored thyroid surgery. Prospective crossover study METHODS: EMG responses obtained via endotracheal tube surface electrodes in 11 patients undergoing thyroid surgery were recorded when stimulated with four stimulators: two monopolar (Prass standard and ball tip), one bipolar, and one dissecting instrument. Normative mean EMG results including latency, amplitude, threshold, saturation currents, and distance-sensitivity were compared. The Prass standard stimulator had shorter latency time when nerve was not covered with fascia (P = .04). The bipolar, dissecting instrument, and ball tip demonstrated similar latency times with and without nerve fascia. Pooled mean latency increased significantly from 1.86 ms to 2.16 ms when comparing nerves without fascia and nerves with fascia (P < .05). The Prass standard monopolar stimulator had the lowest mean threshold at 0.40 mA, with the dissecting instrument having the highest threshold at 0.89 mA for dissected nerve. Pooled mean threshold and saturation increased from 0.6 mA to 1.7 mA (P < .0001) and 1.57 mA to 4.15 mA (P < .001) with fascia covering nerve, respectively. The mean depolarization rate was 100% for monopolar and bipolar electrodes and 81% for dissecting instrument at 1 mA. Only 9% of monopolar electrodes generated an EMG response when stimulated from 2 mm away. Monopolar stimulators are more sensitive for neural mapping, whereas bipolar instruments are more specific, thus reducing false positive stimulation. Dissecting instruments share many features of monopolar stimulators while being more specific, and thus are a viable alternative. 2b Laryngoscope, 2020.

Prolonged inhibitory effects against planktonic growth, adherence, and biofilm formation of pathogens causing ventilator-associated pneumonia using a novel polyamide/silver nanoparticle composite-coated endotracheal tube

Microbial cells can rapidly form biofilm on endotracheal tubes (ETT) causing ventilator-associated pneumonia, a serious complication in patients receiving mechanical ventilation. A novel polyamide with a good balance of hydrophilic/hydrophobic moieties was used for the embedment of green-reduction silver nanoparticles (AgNPs) for the composite-coated ETT. The films were conformal with a thickness of ∼ 17 ± 3 µm accommodating high loading of 60 ± 35 nm spherical-shaped AgNPs. The coated ETT resulted in a significant difference in reducing both planktonic growth and microbial adhesion of single and mixed-species cultures, compared with uncoated ETT (p < 0.05). A time-kill assay demonstrated rapid bactericidal effects of the coating on bacterial growth and cell adhesion to ETT surface. Biofilm formation by Pseudomonas aeruginosa and Staphylococcus aureus, commonly encountered pathogens, was inhibited by > 96% after incubation for 72 h. Polyamide/AgNP composite-coated ETT provided a broad-spectrum activity against both Gram-positive and Gram-negative bacteria as well as Candida albicans and prolonged antimicrobial activity.

Incidence of Biofilm Formation in ET Tube and Correlation with Occurrence of VAP in a Tertiary Care ICU

Introduction: VAP is one of the most frequent hospital-acquired infections occurring in mechanically ventilated patients and is associated with increased mortality, morbidity, and health-related costs. Bacterial biofilm has been observed universally on the surface of endotracheal tubes in mechanically ventilated patients. Some data show a good concordance between bacterial colonization of the airway and microbial findings in the biofilm. Even the same microorganisms causing VAP could be found in the ETT biofilm leading to the potential implication of biofilm in the genesis of VAP. Aims and Objectives: The objective was to investigate the involvement of ETT biofilm in VAP pathogenesis. Materials and Methods: This observational descriptive study was conducted in Department of Pulmonary Medicine, D.Y Patil Hospital, Nerul, Navi Mumbai. Approval of Institutional Ethics Committee was taken before start of the study. A written signed informed consent was taken prior to enrolling the subjects in the study. Patients requiring mechanical ventilation for at least 24 hours were included in the study. The following data were recorded in a standardized form: age and sex of the patient, cause of mechanical ventilation, duration of ventilation, manoeuvres to prevent VAP, the occurrence or not of nosocomial pneumonia, together with data of pathogen isolated in respiratory samples and/or ETT biofilm, antibiotic therapy and sensitivity patterns. Statistical Method: Descriptive and analytical statistics was done. The data was analyzed using statistical software (IBM SPSS V20.1, IBM Corporation, Armonk, NY, USA). The results are expressed as mean ± standard deviation and proportions. Categorical variables were compared using chi-square tests. The statistical significance was determined at p<0.05.Results: A total of 55 subjects fulfilling the inclusion criteria were participated in the study. The mean age of the study population was 46.56 19.79 with a range of 18 to 87 years. There were 23 (41.8%) males and 32 (58.2%) female’s subjects in the study population. The patients were intubated for mainly three reasons – AHF, ARF and CVA. The diagnosis of the ventilated patients was as follows – pneumonia (25.4%), ARDS (18.2%), cerebral stroke (16.4%), septic shock (16.4%), hemorrhagic shock (9.1%), cardiac arrest (7.3%), cardiopulmonary failure (5.4%) and interstitial lung disease (1.8%). The mean duration of intubation was 10.23 1.55, ICU days was 13.45 1.34 and hospital days was 19.72 2.84. Out of the 55 ventilated patients, 9 (16.3%) patients developed VAP. Biofilm was found positive in 30 (54.5%) patients. In the present study the three most common organisms found in ET tube were Acinetobacter (23.6%), klebsiella (18.2%), E.Coli (7.3%). The other organisms found were Pseudomonas (7.3%), Candida Albicans (3.6%) and staphylococcus (1.8%). The incidence of VAP development in biofilm positive cases was 30%. Conclusion: Biofilms are highly organized microbial communities which in vivo play an important part in evading the defence mechanism and obstinate the antimicrobial therapy. The precise link between biofilm productions in mechanically ventilated patients is still obscure apart from some limited studies which have described role of a specific pathogen or virulence factor. The present study, thus, showed that majority of the pathogens isolated possessed capability to produce biofilm.

Non-Pharmacological Interventions to Prevent Ventilator-Associated Pneumonia: A Literature Review.

Ventilator-associated pneumonia (VAP) is a well-known complication of invasive mechanical ventilation in critically ill patients. The presence of an endotracheal tube (ETT) is one of the major culprits for VAP development: air flow moves pathogens toward the distal airways, while clearance of the trachea is blunted due to reduced tracheal ciliary movement and impaired cough. Several measures are recognized as being useful to prevent VAP, and these are usually grouped in a VAP bundle (ie, avoiding intubation or re-intubation whenever possible; head of bed elevation; hand hygiene; shortening ventilation through sedation interruptions, spontaneous breathing trials, or thromboembolic prophylaxis). However, other interventions have been proposed to reduce VAP rate; some of these interventions have been reported in large clinical trials to be effective, some have been evaluated in small observational studies, and still others at a pre-clinical stage. Some strategies aim to improve the ETT design via a subglottic drainage system, with treatment of the ETT surface to reduce pathogen activity, or by modification of the cuff shape or cuff material to provide a better seal. Another proposed strategy is improving airway care through control of cuff pressure, cleaning the ETT, or use of closed suction systems. Other interventions target a patient's position in the bed to reduce aspiration of digestive content in the airways, or the use of probiotics to modulate gastric flora. Some of these measures are supported by strong evidence, but the impact on relevant outcomes such as duration of ventilation or mortality, as well as cost-benefit ratio, is still unclear, resulting in lack of widespread use.