The pathogenesis of ventilator-associated pneumonia: I. Mechanisms of bacterial transcolonization and airway inoculation

Nomogram to predict ventilator-associated pneumonia in large vessel occlusion stroke after endovascular treatment: a retrospective study

Background

Ventilator-Associated Pneumonia (VAP) severely impacts stroke patients' prognosis after endovascular treatment. Hence, this study created a nomogram to predict the occurrence of VAP after endovascular treatment.

Methods

The individuals with acute ischemic stroke and large vessel occlusion (AIS-LVO) who received mechanical ventilation and endovascular therapy between July 2020 and August 2023 were included in this retrospective study. The predictive model and nomogram were generated by performing feature selection optimization using the LASSO regression model and multifactor logistic regression analysis and assessed the evaluation, verification and clinical application.

Results

A total of 184 individuals (average age 61.85 ± 13.25 years, 73.37% male) were enrolled, and the rate of VAP occurrence was found to be 57.07%. Factors such as the Glasgow Coma Scale (GCS) score, duration of stay in the Intensive Care Unit (ICU), dysphagia, Fazekas scale 2 and admission diastolic blood pressure were found to be associated with the occurrence of VAP in the nomogram that demonstrating a strong discriminatory power with AUC of 0.862 (95% CI, 0.810-0.914), and a favorable clinical net benefit.

Conclusion

This nomogram, comprising GCS score, ICU duration, dysphagia, Fazekas scale 2 and admission diastolic blood pressure, can aid clinicians in predicting the identification of high-risk patients for VAP following endovascular treatment in large vessel occlusion stroke.

Development and validation of a nomogram for pneumonia risk in burn patients with inhalation injury: a multicenter retrospective cohort study

BACKGROUND

Burn patients with inhalation injury are at higher risk of developing pneumonia, and yet there is no reliable tool for the assessment of the risk for such patients at admission. This study aims to establish a predictive model for pneumonia risk for burn patients with inhalation injury based on clinical findings and laboratory tests.

METHOD

This retrospective study enrolled 546 burn patients with inhalation injury. They were grouped into a training cohort and a validation cohort. The least absolute shrinkage and selection operator (LASSO) regression analysis and binary logistic regression analysis were utilized to identify risk factors for pneumonia. Based on the factors, a nomogram for predicting pneumonia in burn patients with inhalation injury was constructed. Areas under the receiver operating characteristic curves (AUC), calibration plots, and decision curve analysis (DCA) were used to evaluate the efficiency of the nomogram in both the training and validation cohorts.

RESULTS

The training cohort included 432 patients, and the validation cohort included 114 patients, with a total of 225 (41.2%) patients experiencing pneumonia. Inhalation injury, tracheal intubation/tracheostomy, low serum albumin, and high blood glucose were independent risk factors for pneumonia in burn patients with inhalation injury and they were further used to build the nomogram. The AUC of the nomogram in the training and validation cohorts were 0.938 (95% CI: 0.917-0.960) and 0.966 (95% CI: 0.931-1), respectively. The calibration curve for probability of pneumonia showed optimal agreement between the prediction by nomogram and the actual observation, and the DCA indicated that the constructed nomogram conferred high clinical net benefit.

CONCLUSION

This nomogram can accurately predict the risk of developing pneumonia for burn patients with inhalation injury, and help professionals to identify high-risk patients at an early stage as well as to make informed clinical decisions.

Clinico-Microbiological Correlates of Hospital-Acquired Pneumonia: A Hospital-Based Prospective Cohort Study

BACKGROUND AND OBJECTIVES

Hospital-acquired pneumonia (HAP) is a life-threatening hospital-acquired infection contributing to poor outcomes and mortality. Though the prevalence is comparable, the burden of comorbidities and malnutrition further worsens the scenario in developing countries. Infective agents responsible for these infections vary between regions due to the variables involved. There is a dearth of data on clinico-microbiological correlates of HAP from Northern India. With this study, we aim to explore the same and add more evidence to fill the gap.

METHODOLOGY

A hospital-based cohort study was done on ICU patients of the tertiary care center in Northern India including the cohort of patients obeying a strict inclusion criterion. The clinical and microbiological correlates were estimated following an appraisal of quality of study samples.

RESULTS

We found that the most common clinical feature in patients with HAP was fever (82%) followed by purulent respiratory secretions (72%), tachycardia (52%), and crepitations on auscultation (38%). Approximately 86% of cases were found to be culture-positive while others were bacteriologically sterile. Gram-negative bacilli were more commonly isolated (83% Gram-negative vs 17% Gram-positive). The most common organisms isolated were Klebsiella pneumoniae, Citrobacter freundii, Escherichia coli, Acinetobacter, and Pseudomonas aeruginosa. Staphylococcus aureus was isolated from eight specimens and all isolates were susceptible to vancomycin, linezolid, teicoplanin, and tigecycline. Seven isolates were resistant to clindamycin and all 8 were resistant to macrolides and quinolones. Five strains had methicillin resistance indicating a rising burden of 'superbugs'. The most common side involved was the right side and the right middle zone was the most common zone involved. Forty-four percent of cases had a poor outcome and succumbed to the infection.

CONCLUSIONS

HAP places patients at a heightened risk of mortality and manifests a distinctive clinical-microbiological profile. It is advisable to adopt a proactive stance in averting HAI by adhering to robust prophylaxis and management protocols in alignment with regional data and hospital guidelines. Despite the study's constrained sample size, it contributes significant insights specific to the region. This underscores the necessity for further exploration through analogous studies and audits in the northern part of India. Such endeavors have the potential to tailor treatment approaches for patients, ultimately enhancing overall outcomes.

Quantitative oral health assessments in mechanically ventilated patients: A scoping review

BACKGROUND

Oral health is a key contributor to a person's overall health. Previous studies indicate that oral health deteriorates throughout ventilation and may contribute to the development of ventilator-associated pneumonia (VAP). Oral health at the time of initial ventilation may impact on this deterioration.

AIMS

To determine the quantitative clinical assessment methods used to measure oral health and what is currently known regarding the oral health of patients at the time of initial ventilation.

STUDY DESIGN

A systematic literature search using electronic bibliographic databases MEDLINE/PubMed, Embase, CINAHL, and the Cochrane Library was undertaken for this scoping review. Studies were included if patients were >18 years old and mechanically ventilated for <48 h at the time of the first oral assessment.

RESULTS

In total, 12 studies were included. The review demonstrates a limited understanding of clinical oral health at the time of initial ventilation. Significant variation in both assessment methods and reporting of oral health makes comparison of results difficult resulting in a poor overall understanding of oral health at the time of intubation.

CONCLUSION

Standardized assessment and reporting methods may improve clinical application of findings and help direct future research. We suggest developing a core outcome set to ensure consistent use of assessment tools as well as standardized reporting of results.

RELEVANCE TO CLINICAL PRACTICE

It is essential that a good understanding of oral health at the time of initial ventilation is gained so that patients receive more targeted oral hygiene intervention in ICU, potentially leading to improved patient outcomes.

Poor Oral Health in the Etiology and Prevention of Aspiration Pneumonia

Aspiration pneumonia (AP), inflammation of the lung parenchyma initiated by aspirated microorganisms into the lower airways from proximal sites, including the oral cavity, is prevalent in, and problematic for, the elderly, especially those in institutions, and for those with several important risk factors. Many factors influence the pathogenesis of AP, including dysphagia, poor oral hygiene, diminished host defense, and underlying medical conditions. This article reviews the epidemiology, microbiology, pathogenesis, and prevention of AP, focusing on the role of poor oral health as a risk factor for, and on dental care for the prevention and management of, this important infection.

Relationship Between Intra-Abdominal pressure and microaspiration of gastric contents in critically ill mechanically ventilated patients

The relationship between increased intra-abdominal pressure (IAP) and microaspiration of oro-gastric content in mechanically-ventilated patients has not yet been established. Microaspiration is proposed as one of the causes of ventilator-associated pneumonia (VAP). We aimed to investigate whether mechanically-ventilated patients with increased IAP present evidence of lung microaspiration by assessing pepsin levels in bronchial secretions and evaluated the relationship between pepsin and VAP. 68 mechanically-ventilated patients and 10 control subjects were recruited from an academic ICU in Greece. IAP, pH, pepsin and total protein levels, in bronchial secretions, were assessed within 14 days. Patients underwent assessment for timely VAP diagnosis based on clinical, radiological and laboratory criteria. Pepsin and total protein levels were significantly elevated in patients compared to controls. Pepsin values correlated significantly with IAP (r = 0.61, ***p < 0.001). Multivariate regression analysis showed that IAP was an independent risk factor for increased pepsin values in bronchial secretions [OR95%CI 1.463(1.061-1.620), *p = 0.014]. Pepsin values were higher in patients with VAP, while IAP was independently associated with VAP. There was an indication towards increased VAP in patients with increased pepsin. In conclusion, our results show that pepsin in bronchial secretions may be elevated when IAP is increased, indicating microaspiration and potentially VAP.

Materiovigilance in Intensive Care Units: An Active Surveillance

Background: Medical devices are the vital part of healthcare system. The use of medical devices is higher in the intensive care units leading to increased exposure rendering the exponential rise in incidence of medical device associated adverse events (MDAEs). Timely detection and reporting of MDAEs can help reduce the disease and associated liabilities. Objective: To determine the rate, patterns, and predictors of MDAEs. Methods: An active surveillance was carried out in the intensive care units (ICUs) of a tertiary care teaching hospital located in southern India. The patients were monitored for MDAEs which were reported based on MvPI guidance document 1.2. The predictors were calculated using an odds ratio at 95% confidence interval. Results: A total of 185 MDAEs were reported amongst 116 patients, of which the majority [74 (63.7%)] were males. Most of the MDAEs were attributed to urethral-catheters [42 (22.7%)] among which a high majority of 34 were associated with urinary tract infections (UTI), followed by ventilators [35 (18.9%)] with all events causing pneumonia. Urethral catheters and ventilators are both classified as categories B and C respectively based on device risk classification provided by the Indian Pharmacopoeia Commission (IPC). Over 58% of MDAEs were reported among the elderly. The causality assessment was possible for 90 (48.6%) MDAEs whereas 86 (46.4%) were probable. The majority of the MDAEs reported were serious [165 (89.2%)] and only [20 (10.8%)] were found to be non-serious on the severity scale. Most [104 (56.2%)] of the devices attributed to MDAEs were single-use devices, of which [103 (55.6%)] were destroyed and only [81 (43.7%)] were retained in healthcare facilities. Conclusions: Despite the best possible care in the intensive care units (ICUs), MDAEs are inevitable, adding to the burden of patients in terms of suffering, disease, extended hospital stay, and increased costs. MDAEs require rigorous monitoring of patients, especially in the elderly population and patients with increased exposure to multiple devices.

Ventilator-Associated Pneumonia Prevention in Pediatric Patients: Narrative Review

Ventilator-associated pneumonia (VAP), one of the most common healthcare-associated infections in intensive care settings, is associated with significant morbidity and mortality. VAP is diagnosed in >10% of patients on mechanical ventilation, incidence rising with number of ventilator days. In recent decades, the pathophysiology of VAP, VAP risk factors and treatment have been extensively studied. In critically ill pediatric patients, mechanical issues such as insufficient tightness of the ventilator circuit (mainly due to historically based preference of uncuffed tubes) and excessive humidity in the circuit are both significant risk factors of VAP development. Protocol-based approaches to critically ill patients on mechanical ventilation, closed suctioning, upper body position, enteral feeding and selective gastric acid suppression medication have a beneficial effect on VAP incidence. In recent decades, cuffed tubes applied to the whole spectrum of critically ill pediatric patients (except neonates <2700 g of weight), together with cuff-oriented nursing care including proper cuff-pressure (<20 cm H2O) management and the use of specialized tracheal tubes with subglottic suction ports combined with close infraglottic tracheal suctioning, have been implemented. The aim of this review was to summarize the current evidence-based knowledge about the pathophysiology, risk factors, diagnosis, treatment and prevention of VAP in clinically oriented settings.

Nebulized Antibiotics for Healthcare- and Ventilator-Associated Pneumonia

Global emergence of multidrug-resistant and extensive drug-resistant gram-negative bacteria has increased the risk of treatment failure, especially for healthcare- or ventilator-associated pneumonia (HAP/VAP). Nebulization of antibiotics, by providing high intrapulmonary antibiotic concentrations, represents a promising approach to optimize the treatment of HAP/VAP due to multidrug-resistant and extensive drug-resistant gram-negative bacteria, while limiting systemic antibiotic exposure. Aminoglycosides and colistin methanesulfonate are the most common nebulized antibiotics. Although optimal nebulized drug dosing regimen is not clearly established, high antibiotic doses should be administered using vibrating-mesh nebulizer with optimized ventilator settings to ensure safe and effective intrapulmonary concentrations. When used preventively, nebulized antibiotics reduced the incidence of VAP without any effect on mortality. This approach is not yet recommended and large randomized controlled trials should be conducted to confirm its benefit and explore the impact on antibiotic selection pressure. Compared with high-dose intravenous administration, high-dose nebulized colistin methanesulfonate seems to be more effective and safer in the treatment of ventilator-associated tracheobronchitis and VAP caused by multidrug resistant and extensive-drug resistant gram-negative bacteria. Adjunctive nebulized aminoglycosides could increase the clinical cure rate and bacteriological eradication in patients suffering from HAP/VAP due to multidrug-resistant and extensive drug-resistant gram-negative bacteria. As nebulized aminoglycosides broadly diffuse in the systemic circulation of patients with extensive bronchopneumonia, monitoring of plasma trough concentrations is recommended during the period of nebulization. Large randomized controlled trials comparing high dose of nebulized colistin methanesulfonate to high dose of intravenous colistin methanesulfonate or to intravenous new β-lactams in HAP/VAP due to multidrug-resistant and extensive drug-resistant gram-negative bacteria are urgently needed.

Oral Care in Critically Ill Patients Requiring Noninvasive Ventilation: An Evidence-Based Review

TOPIC

Hospital-acquired pneumonia commonly develops after 48 hours of hospitalization and can be divided into non-ventilator-acquired and ventilator-acquired pneumonia. Prevention of non-ventilator-acquired pneumonia requires a multimodal approach. Implementation of oral care bundles can reduce the incidence of ventilator-acquired pneumonia, but the literature on oral care in other populations is limited.

CLINICAL RELEVANCE

Use of noninvasive ventilation is increasing owing to positive outcomes. The incidence of non-ventilator-acquired pneumonia is higher in patients receiving noninvasive ventilation than in the general hospitalized population but remains lower than that of ventilator-acquired pneumonia. Non-ventilator-acquired pneumonia increases mortality risk and hospital length of stay.

PURPOSE

To familiarize nurses with the evidence regarding oral care in critically ill patients requiring noninvasive ventilation.

CONTENT COVERED

No standard of oral care exists for patients requiring noninvasive ventilation owing to variation in study findings, definitions, and methods. Oral care decreases the risk of hospital-acquired pneumonia and improves comfort. Nurses perform oral care less often for nonintubated patients, as it is perceived as primarily a comfort measure. The potential risks of oral care for patients receiving noninvasive ventilation have not been explored. Further research is warranted before this practice can be fully implemented.

CONCLUSION

Oral care is a common preventive measure for non-ventilator-acquired pneumonia and may improve comfort. Adherence to oral care is lower for patients not receiving mechanical ventilation. Further research is needed to identify a standard of care for oral hygiene for patients receiving noninvasive ventilation and assess the risk of adverse events.

Microbial etiologies of ventilator-associated pneumonia (VAP) in intensive care unit of Beni-Suef University's Hospital

Background

Ventilator-associated pneumonia (VAP) is a major health problem for people intubated in intensive care units (ICUs), leading to increased mortality rates, hospital stay, and treatment costs. In the present study, the core pathogens causing VAP in Beni-Suef University's Hospital, Egypt, was investigated over a study period of 2 years (2017–2019).

Results

Of a total of 213 patients subjected to mechanical ventilation, 60 have developed VAP during their stay in the ICU. The mortality rate reached 41.7% among VAP patients. Sixty bacteria were isolated from an endotracheal aspirate of hospitalized patients. The different isolates were cultured followed by running biochemical tests, sensitivity assays, and automated VITEK®2 System analysis. Unexpectedly, all the isolates were Gram-negative bacteria. Klebsiella pneumoniae were the main pathogen encountered (27/60 isolates) followed by Acientobacter baumannnii (7/60) and other microorganisms belonging to the genera Moraxella, Escherichia, and Pseudomonas (11/60). Antibiotic sensitivity testing was performed via the VITEK®2 System using up to 16 different antibiotics representing 8 different antibiotic classes and subclasses (aminoglycosides, carbapenems, fluoroquinolones, penicillin/β-lactamase inhibitor, extended-spectrum cephalosporins, aminopenicillins, aminopenicillins/β-lactamase inhibitor, folic acid synthesis inhibitor). Majority of the isolates (28/60) showed a remarkable extensive drug resistance (XDR) pattern, while 15 isolates were multi-drug resistant (MDR) and only 6 were pan-drug resistant (PDR) with regard to antibiotics under evaluation.

Conclusion

The association of VAP with multi-drug-resistant bacteria is alarming, and rapid management is crucial. Identification of core pathogens is essential for identifying the most appropriate technique for infection control.

Comprehensive Analysis of Heat and Water Exchanges in the Human Lungs

This work presents a new mathematical model of the heat and water exchanges in the human lungs (newborn to adult). This model is based on a local description of the water and energy transports in both the lumen and the surrounding tissues, and is presented in a comprehensive, dimensionless framework with explicitly stated assumptions and a strong physiological background. The model is first used to analyze and quantify the key phenomena and dimensionless numbers governing these heat and water exchanges and then it is applied to an adult in various situations (varying atmospheric conditions, exercising…). The results highlight several interesting physiological elements. They show that the bronchial region of the lungs is able to condition the air in all the considered situations even if, sometimes, for instance when exercising, distal generations have to be involved. The model also shows that these distal generations are super-conditioners. Moreover, the results quantify the key role of the submucosal glands in mucus hydration. They also show that, during expiration, a significant cooling of the air and condensation of water occur along the respiratory tract as the vascularization of the tissues surrounding the airways is not able to maintain these tissues at body temperature during inspiration. Due to the interaction between several phenomena, it appears that the ratio of the amount of water returned to the mucosa during expiration to the amount extracted during inspiration is almost independent of the breathing conditions (around 33%). The results also show that, in acute situations, such as suffering from a pathology with airway dysfunction, when being intubated or when exercising above an intensity threshold, the heat and water exchanges in the lungs may be critical regarding mucus hydration. In proximal generations, the evaporation may overwhelm the ability of the submucosal glands to replenish the airway surface liquid with water. In some situations, the cooling of the mucosa may be very important; it can even become colder than the inspired air, due to evaporative cooling. Finally, the results show that breathing cold air can significantly increase the exchanges between the lungs and the environment, which can be critical regarding disease transmission.

Promoting subglottic secretion drainage: a quality improvement project in a UK critical care unit

The aim of the study was to promote the practice of subglottic secretion drainage (SSD) in a UK critical care unit. SSD is a technique employed to reduce microaspiration of oropharyngeal secretions in patients with cuffed endotracheal airways. Aspiration of oropharyngeal secretions is the accepted cause of the majority of ventilator-associated pneumonia (VAP), a complication of invasive ventilation with high associated mortality. The plan–do–study–act methodology was employed. The local critical care patient database was searched for patients requiring mechanical ventilation via a tracheostomy tube with subglottic port in the 3 months prior to intervention. Patient records were interrogated for evidence of the practice of SSD. The intervention involved the introduction of a tracheostomy care bundle to be prescribed on insertion of a tracheostomy on the critical care unit, in combination with departmental teaching. The bundle included prompts for nursing staff to practise regular SSD and to complete a tracheostomy care plan at the end of shift. A total of 24 patients were included. A review of practice was conducted every 3 months for 1 year. This showed an improvement in documented evidence of SSD from 0% of days at baseline to 85.7% of days at 1 year. Implementation of a tracheostomy order set prescribing regular SSD resulted in an improvement in the practice of SSD in patients ventilated via tracheostomy. This has implications for patient outcomes and healthcare costs, given that SSD has been shown to reduce incidence of VAP.

Endotracheal Tube Cuff Pressure - Comparison of the Two Filling Methods - Simulated Test

INTRODUCTION

Tracheal intubation is the optimal method for opening up airways. Performed correctly, it prevents stomach contents from entering the respiratory tract and allows asynchronous cardiopulmonary resuscitation (CPR) to be conducted during sudden cardiac arrest. An important element of correct intubation is proper inflation of the endotracheal tube cuff. Research has shown that when medical personnel use the palpation technique, the cuff is usually inflated incorrectly. This can result in numerous health complications for the patient.

METHODS

This research was conducted in 2020 on a group of paramedics participating in the 15th International Winter Championship of Medical Rescuers in Bielsko-Biala (Poland). The aim of the research was to assess two methods of inflating the endotracheal tube cuff. Method A involved inflating the cuff using a syringe and assessing the pressure in the control cuff using the palpation technique. Method B involved inflating the cuff using a manometer. During the inflation, both the cuff inflation pressure and the time required to complete the procedure were recorded. Analysis was also conducted on whether completion of certified Advanced Life Support (ALS) and Advanced Cardiovascular Life Support (ACLS) training had any influence on the effectiveness of the inflation procedure.

RESULTS

The research showed that paramedics using Method B significantly more often inflated the endotracheal tube cuff to the correct pressure than those using Method A. However, when Method B was used, the procedure took longer to conduct. The study also showed that completion of certified ALS or ACLS training did not have a significant influence on proper inflation of the cuff. Those who had completed certified training courses took significantly longer to inflate the endotracheal tube cuff when using Method A.

CONCLUSIONS

Inflation of the endotracheal tube cuff by use of a syringe, followed by the palpation technique for assessing the inflation of the cuff balloon, is ineffective. Paramedic teams should be equipped with manometers to be used for inflating the endotracheal tube cuff.

Continuous Pneumatic Regulation of Tracheal Cuff Pressure to Decrease Ventilator-associated Pneumonia in Trauma Patients Who Were Mechanically Ventilated: The AGATE Multicenter Randomized Controlled Study

BACKGROUND

Ventilator-associated pneumonia (VAP) is the most frequent health care-associated infection in severely ill patients, and aspiration of contaminated oropharyngeal content around the cuff of the tracheal tube is the main route of contamination.

RESEARCH QUESTION

Is continuous regulation of tracheal cuff pressure using a pneumatic device superior to manual assessment three times daily using a portable manometer (routine care) in preventing VAP in patients with severe trauma?

STUDY DESIGN AND METHODS

In this open-label, randomized controlled superiority trial conducted in 13 French ICUs, adults (age ≥ 18 years) with severe trauma (Injury Severity Score > 15) and requiring invasive mechanical ventilation for ≥ 48 h were enrolled. Patients were randomly assigned (1:1) via a secure Web-based random number generator in permuted blocks of variable sizes to one of two groups according to the method of tracheal cuff pressure control. The primary outcome was the proportion of patients developing VAP within 28 days following the tracheal intubation, as determined by two assessors masked to group assignment, in the modified intention-to-treat population. This study is closed to new participants.

RESULTS

A total of 434 patients were recruited between July 31, 2015, and February 15, 2018, of whom 216 were assigned to the intervention group and 218 to the control group. Seventy-three patients (33.8%) developed at least one episode of VAP within 28 days following the tracheal intubation in the intervention group compared with 64 patients (29.4%) in the control group (adjusted subdistribution hazard ratio, 0.96; 95% CI, 0.76-1.20; P = .71). No serious adverse events related to the use of the pneumatic device were noted.

INTERPRETATION

Continuous regulation of cuff pressure of the tracheal tube using a pneumatic device was not superior to routine care in preventing VAP in patients with severe trauma.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT02534974; URL: www.clinicaltrials.gov.

Poor Oral Health in the Etiology and Prevention of Aspiration Pneumonia

Aspiration pneumonia (AP), inflammation of the lung parenchyma initiated by aspirated microorganisms into the lower airways from proximal sites, including the oral cavity, is prevalent in, and problematic for, the elderly, especially those in institutions, and for those with several important risk factors. Many factors influence the pathogenesis of AP, including dysphagia, poor oral hygiene, diminished host defense, and underlying medical conditions. This article reviews the epidemiology, microbiology, pathogenesis, and prevention of AP, focusing on the role of poor oral health as a risk factor for, and on dental care for the prevention and management of, this important infection.

Severe COVID-19 Lung Infection in Older People and Periodontitis

Periodontal bacteria dissemination into the lower respiratory tract may create favorable conditions for severe COVID-19 lung infection. Once lung tissues are colonized, cells that survive persistent bacterial infection can undergo permanent damage and accelerated cellular senescence. Consequently, several morphological and functional features of senescent lung cells facilitate SARS-CoV-2 replication. The higher risk for severe SARS-CoV-2 infection, the virus that causes COVID-19, and death in older patients has generated the question whether basic aging mechanisms could be implicated in such susceptibility. Mounting evidence indicates that cellular senescence, a manifestation of aging at the cellular level, contributes to the development of age-related lung pathologies and facilitates respiratory infections. Apparently, a relationship between life-threatening COVID-19 lung infection and pre-existing periodontal disease seems improbable. However, periodontal pathogens can be inoculated during endotracheal intubation and/or aspirated into the lower respiratory tract. This review focuses on how the dissemination of periodontal bacteria into the lungs could aggravate age-related senescent cell accumulation and facilitate more efficient SARS-CoV-2 cell attachment and replication. We also consider how periodontal bacteria-induced premature senescence could influence the course of COVID-19 lung infection. Finally, we highlight the role of saliva as a reservoir for both pathogenic bacteria and SARS-CoV-2. Therefore, the identification of active severe periodontitis can be an opportune and valid clinical parameter for risk stratification of old patients with COVID-19.

Smart secretion management to protect nurses from COVID19 and other infectious diseases

Background

COVID‐19 has been linked to over 40 million infections and 1.1 million deaths in 210 countries as of October 19, 2020. This highly contagious communicable disease has put not only infected individuals but other patients and frontline workers like nurses at risk in hospitals, especially in Intensive Care units (ICUs).

There is a need for minimizing patient contact, improving hand hygiene practices, and optimizing healthcare provider time, especially nurses. Globally it is estimated that nearly a million health care providers have been infected with COVID‐19 as of the end of October 2020.

Methods

This retrospective service evaluation documents the experience of health care providers in a COVID‐19 ICU in India that was used to implement new protocols for secretion management and oral hygiene. Patient chart information and staff feedback were utilized.

Intervention

This pilot study captures the practical benefits of using VAPCare, an automated, closed‐loop system for oral secretion removal.

Results

Six patients were included in this small‐scale study; three patients following the current standard of care for suctioning and oral hygiene and three receiving the new VAPCare and Lumen device protocol. With the new device protocol, the number of infected secretion interactions by a nurse was 50% lower, and nursing time spent on oral hygiene and secretion management 70% less than seen with the current standard of care. The number of disposable gloves used with VAPCare and Lumen was reduced by over 50%. All 10 nurses and six doctors gave positive feedback on device usage. The department recommended updating protocols to prioritize the use of the new secretion management system for patients with COVID19 and other highly contagious conditions.

Conclusion

The findings are an early indication that using VAPCare for patients could help protect infected patients, other ICU patients, and health care workers.

Enhanced oral hygiene interventions as a risk mitigation strategy for the prevention of non-ventilator-associated pneumonia: a systematic review and meta-analysis

Background Healthcare-acquired pneumonias are a significant risk for nursing home and hospital patients. While oral care interventions (OCIs) have been found to be effective in reducing the risk of ventilator-associated pneumonia (VAP), their utility in mitigating non-ventilator-associated pneumonias (NVAP) remains unknown. We performed a structured meta-analysis of randomised and non-randomised clinical trials of enhanced oral hygiene procedures on NVAP.Methods We searched PubMed and Embase to include clinical trials (randomised and non-randomised), and observational (retrospective and prospective) and quasi-experimental studies examining the effect of any method of OCI on incidence of NVAP.Results After quality assessment and consensus agreement between authors, we synthesised six randomised clinical trials (3,891 patients), two non-randomised trials (2,993 patients), and separately assessed a retrospective trial (143 patients) and a quasi-experimental study (83 patients). Most studies, performed in nursing homes, did not show a significant association between OCI and NVAP prevention (RR random 0.89, 95% CI 0.64-1.25, p value 0.50). Likewise, the non-randomised trials failed to show an association between NVAP risk and OCI (RR random 1.42, 95% CI, 0.70-2.88, p value 0.32). However, in the subgroup analysis comparing dental professional involvement in care vs usual care, reduced NVAP risk was demonstrated (RR random 0.65, 95% CI 0.43-0.98, p value 0.03).Conclusions Study results suggest that professional dental care may confer some benefit among NVAP patients. The lack of consistent OCI protocols, data in hospitalised patients and robust randomised clinical trials do not allow definitive conclusions about the contribution of OCI in mitigating NVAP risk.

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

BACKGROUND

Biofilm 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.

METHODS

We 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.

RESULTS

High-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.

CONCLUSION

High-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 REGISTRATION

ClinicalTrials.gov NCT02284438 . Retrospectively registered on 21 October 2014.

Evaluation of the Novel Antimicrobial BCP3 in a Coating for Endotracheal Tubes

Ventilator-associated pneumonia (VAP) is a highly common hospital-acquired infection affecting people that require mechanical ventilation. The endotracheal tube (ETT) used during the ventilation process provides a surface that can allow bacterial colonization and biofilm formation, which can lead to VAP. Although various approaches, including ETT design and material selection, as well as antimicrobial coatings have been employed to minimize adverse events, VAP remains a significant unresolved clinical issue. In this study, we have utilized a novel styrylbenzene-based antimicrobial (BCP3) in a simple and robust coating that allows its long-term release at an effective level. BCP3 was applied onto PVC ETT segments blended together with poly(lactic-co-glycolic acid) via a facile dip-coating process with controlled loadings. In vitro studies demonstrated concentration-dependent release of BCP3 from the coatings for at least 31 days. Bacterial assays using major VAP culprits, Staphylococcus aureus and Pseudomonas aeruginosa, demonstrated significant growth inhibition, with a stronger effect on S. aureus. Despite its ability to inhibit bacterial growth, BCP3 showed no cytotoxicity toward mammalian (L929) fibroblasts, which makes it attractive from a clinical perspective. The coating procedure was successfully translated to coat the entire ETTs, making it highly amenable for large-scale manufacturing.

Predictive risk factors for postoperative pneumonia after heart transplantation

Background

Pneumonia is a frequent complication in patients undergoing heart transplantation (HTx) that increases morbidity and mortality in this population. Nevertheless, the risk factors for postoperative pneumonia (POP) are still unknown. The aim of this study was to investigate the predictive risk factors for POP in HTx recipients.

Methods

In this retrospective study, all patients undergoing HTx between January 2014 and December 2015 were included. All cases of POP occurring until hospital discharge were investigated. The study aimed to determine risk factors using univariate and multivariate Cox regression models. Data are expressed in Odds Ratio [95% CI]. P < 0.05 was necessary to reject the null hypothesis.

Results

A total of 175 patients were included without any patients being lost to follow-up, and 89 instances of POP were diagnosed in 59 (34%) patients. Enterobacteriaceae and Pseudomonas aeruginosa were the most common pathogens. In the multivariate analysis, the risk factors were preoperative mechanical ventilation (OR 1.42 [1.12–1.80], P < 0.01) and perioperative blood transfusion (OR 1.42 [95% CI: 1.20–1.70], P < 0.01). POP significantly impacted mortality at 30 days (OR: 4 [1.3–12.4], P = 0.01) and 1 year (OR: 6.8 [2.5–8.4], P < 0.01) and was associated with a longer duration of mechanical ventilation, time to weaning from venoarterial extracorporeal membrane oxygenation and stay in an intensive care unit. Plasma exchanges and intravenous administration of immunoglobulins did not increase the risk of POP.

Conclusion

After HTx, preoperative mechanical ventilation and blood transfusion were risk factors for POP and were associated with increased mortality. Enterobacteriaceae and Pseudomonas aeruginosa are the most common pathogens of POP.

Antimicrobial polymer modifications to reduce microbial bioburden on endotracheal tubes and ventilator associated pneumonia

Hospital associated infections (HAIs), infections acquired by patients during care in a hospital, remain a prevalent issue in the healthcare field. These infections often occur with the use of indwelling medical devices, such as endotracheal tubes (ETTs), that can result in ventilator-associated pneumonia (VAP). When examining the various routes of infection, VAP is associated with the highest incidence, rate of morbidity, and economic burden. Although ETTs are essential for the survival of patients requiring mechanical ventilation, their use comes with complications. The presence of an ETT in the airway impairs physiological host defense mechanisms for clearance of pathogens and provides a platform for oropharynx microorganism transport to the sterile tracheobronchial network. Antibiotics are administered to treat lower respiratory infections; however, they are not always effective and consequently can result in increased antibiotic resistance. Prophylactic approaches by altering the surface of ETTs to prevent the establishment and growth of bacteria have exhibited promising results. In addition, passive surface modifications that prevent bacterial establishment and growth, or active coatings that possess a bactericidal effect have also proven effective. In this review we aim to highlight the importance of preventing biofilm establishment on indwelling medical devices, focusing on ETTs. We will investigate successful antimicrobial modifications to ETTs and the future avenues that will ultimately decrease HAIs and improve patient care. STATEMENT OF SIGNIFICANCE: Infections that occur with indwelling medicals devices remain a constant concern in the medical field and can result in hospital-acquired infections. Specifically, ventilator associated pneumonia (VAP) occurs with the use of an endotracheal tube (ETT). Infections often require use of antibiotics and can result in patient mortality. Our review includes a summary of the recent collective work of antimicrobial ETT modifications and potential avenues for further investigations in an effort to reduce VAP associated with ETTs. Polymer modifications with antibacterial nature have been developed and tested; however, a focus on ETTs is lacking and clinical availability of new antimicrobial ETT devices is limited. Our collective work shows the successful and prospective applications to the surfaces of ETTs that can support researchers and physicians to create safer medical devices.

Ventilator-associated pneumonia: The central role of transcolonization

Ventilator-associated pneumonia remain frequent and serious diseases since they are associated with considerable crude mortality. Pathophysiology is centered on modifications of regional bacterial flora, especially tracheobronchial tree and oropharyngeal sphere. Bacterial migration from an anatomical area to another seems to be the main explanation of these alterations which are called "transcolonization". The association of transcolonization and lack of tightness of the endotracheal tube cuff provides a direct pathway for bacteria from the upper to the subglottic airways, eventually leading to ventilator-associated pneumonia. Although modification of bacterial flora has been largely studied, the mechanism which underlays the ability of the implantation, growing and interactions with the local microbiome that leads to the observed transcolonization remains to be more clearly deciphered. The aim of our review is to emphasize the cornerstone importance of the "transcolonization" as a nosological entity playing a central role in ventilator-associated pneumonia.

Is intra-abdominal hypertension a risk factor for ventilator-associated pneumonia?

In the last years, there has been a significant amount of research about the impact of intra-abdominal hypertension (IAH) on the outcomes of critical care patients. IAH is increasingly recognized as potential complication in intensive care unit (ICU) patients. IAH affects all body systems, most notably the cardiac, respiratory, renal, and neurologic systems. IAH affects blood flow to various organs and plays a significant role in the prognosis of the patients. Recognition of IAH, its risk factors and clinical signs can reduce the morbidity and mortality associated. Moreover, knowledge of the pathophysiology may help rationalize the therapeutic approach. On the other hand, ICU patients present frequently ventilator- associated respiratory infections. Ventilator-associated pneumonia (VAP) is the most common healthcare-associated infection (HAI) in adult critical care units. It is associated with increased ICU stay, patient ventilator days and mortality. This paper reviews the relationship between IAH and VAP. Despite animal experimentation and physiological studies on humans, in favor of the impact of IAH to VAP, there is no definitive clinical data that IAH is associated with VAP. Microaspirations form the gastrointestinal track is a pathophysiological mechanism for VAP. This review provides data suggesting that under IAH conditions bacterial translocation might be an additional responsible mechanism for VAP in those patients that merits further investigation in the future.

High seroprevalence of anti-Helicobacter pylori antibodies in patients with ventilator-associated pneumonia

Background:

The pathogenesis of ventilator-associated pneumonia (VAP) is not clearly known. Recently, the role of gastric bacterial colonization has been proposed. The role of gastric colonization with Helicobacter pylori in pathogenesis of VAP was determined by comparing the prevalence of H. pylori in patients with VAP and control participants.

Materials and Methods:

One hundred and eighteen mechanically ventilated patients were divided into two groups; 59 participants with VAP and 59 without VAP. Serologic tests for H. pylori were registered.

Results:

Mean age in seropositive patients was significantly higher. About 71.2% in VAP group and 61.01% in controls were IgG seropositive (P = 0.24). IgM seropositivity was 23.73% versus 8.47% in VAPs and controls, respectively (P = 0.024). By increasing the time of intubation, more patients became seropositive for IgM (Pearson's correlation coefficient = 0.4, P = 0.002).

Conclusion:

IgM seropositivity and serum levels were significantly higher in VAP patients. Furthermore, by increasing the duration of intubation, serum levels for IgM increased significantly.

Intra-Abdominal Hypertension is a Risk Factor for Increased VAP Incidence: A Prospective Cohort Study in the ICU of a Tertiary Hospital

BACKGROUND

Ventilator-associated pneumonia (VAP) might be increased in cases with intra-abdominal hypertension (IAH). However, despite animal experimentation and physiological studies on humans in favor of this hypothesis, there is no definitive clinical data that IAH is associated with VAP. We therefore aimed to study whether IAH is a risk factor for increased incidence of VAP in critical care patients. This 1-center prospective observational cohort study was conducted in the intensive care unit of the University Hospital of Larissa, Greece, during 2013 to 2015. Consecutive patients were recruited if they presented risk factors for IAH at admission and were evaluated systematically for IAH and VAP for a 28-day period.

RESULTS

Forty-five (36.6%) of 123 patients presented IAH and 45 (36.6%) presented VAP; 24 patients presented VAP following IAH. Cox regression analysis showed that VAP was independently associated with IAH (1.06 [1.01-1.11]; P = .053), while there was an indication for an independent association between VAP and abdominal surgery (1.62 [0.87-3.03]; P = .11] and chronic obstructive pulmonary disease (1.79 [0.96-3.37]; P = .06).

CONCLUSIONS

Intra-abdominal hypertension is an independent risk factor for increased VAP incidence in critically ill patients who present risk factors for IAH at admission to the ICU.

Does objective measurement of tracheal tube cuff pressures minimise adverse effects and maintain accurate cuff pressures? A systematic review and meta-analysis

Correct inflation pressures of the tracheal cuff are recommended to ensure adequate ventilation and prevent aspiration and adverse events. However there are conflicting views on which measurement to employ. The aim of this review was to examine whether adjustment of cuff pressure guided by objective measurement, compared with subjective measurement or observation of the pressure value alone, was able to prevent patient-related adverse effects and maintain accurate cuff pressures. A search of PubMed, Web of Science, Embase, CINAHL and ScienceDirect was conducted using keywords 'cuff pressure' and 'measure*' and related synonyms. Included studies were randomised or pseudo-randomised controlled trials investigating mechanically ventilated patients both in the intensive care unit and during surgery. Outcomes included adverse effects and the comparison of pressure measurements. Pooled analyses were performed to calculate risk ratios, effect sizes and 95% confidence intervals. Meta-analysis found preliminary evidence that adjustment of cuff pressure guided by objective measurement as compared with subjective measurement or observation of the pressure value alone, has benefit in preventing adverse effects. These included cough at two hours (odds ratio [OR] 0.42, confidence interval [CI] 0.23 to 0.79, P=0.007), hoarseness at 24 hours (OR 0.49, CI 0.31 to 0.76, P <0.002), sore throat (OR 0.73, CI 0.54 to 0.97, P <0.03), lesions of the trachea and incidences of silent aspiration (P=0.001), as well as maintaining accurate cuff pressures (Hedges' g 1.61, CI 2.69 to 0.53, P=0.003). Subjective measurement to guide adjustment or observation of the pressure value alone may lead to patient-related adverse effects and inaccuracies. It is recommended that an objective form of measurement be used.

CO2 driven endotracheal tube cuff control in critically ill patients: A randomized controlled study

Background

To determine the safety and clinical efficacy of an innovative integrated airway system (AnapnoGuard^™ 100 system) that continuously monitors and controls the cuff pressure (P_cuff), while facilitating the aspiration of subglottic secretions (SS).

Methods

This was a prospective, single centre, open-label, randomized, controlled feasibility and safety trial. The primary endpoint of the study was the rate of device related adverse events (AE) and serious AE (SAE) as a result of using AnapnoGuard (AG) 100 during mechanical ventilation. Secondary endpoints were: (1) mechanical complications rate (2) ICU staff satisfaction; (3) VAP occurrence; (4) length of mechanical ventilation; (5) length of Intensive Care Unit stay and mortality; (6) volume of evacuated subglottic secretions.

Sixty patients were randomized to be intubated with the AG endotracheal-tube (ETT) and connected to the AG 100 system allowing P_cuff adjustment and SS aspiration; or with an ETT combined with SS drainage and P_cuff controlled manually.

Results

No difference in adverse events rate was identified between the groups. The use of AG system was associated with a significantly higher incidence of P_cuff determinations in the safety range (97.3% vs. 71%; p<0.01) and a trend to a greater volume of aspirated SS secretions: (192.0[64–413] ml vs. 150[50–200], p = 0.19 (total)); (57.8[20–88.7] ml vs. 50[18.7–62] ml, p = 0.11 (daily)). No inter-group difference was detected using AG system vs. controls in terms of post-extubation throat pain level (0 [0–2] vs. 0 [0–3]; p = 0.7), hoarseness (42.9% vs. 75%; p = 0.55) and tracheal mucosa oedema (16.7% vs. 10%; p = 0.65).

Patients enrolled in the AG group had a trend to reduced VAP risk of ventilator-associated pneumonia(VAP) (14.8% vs. 40%; p = 0.06), which were more frequently monomicrobial (25% vs. 70%; p = 0.03).

No statistically significant difference was observed in duration of mechanical ventilation, ICU stay, and mortality.

Conclusions

The use AG 100 system and AG tube in critically ill intubated patients is safe and effective in P_cuff control and SS drainage. Its protective role against VAP needs to be confirmed in a larger randomized trial.

Trial registration

ClinicalTrials.gov NCT01550978. Date of registration: February 21, 2012.

Direct Two-Minute Unassisted Breathing Evaluation (DTUBE) is an Attractive Alternative to Longer Spontaneous Breathing Trials: A Prospective Observational Study

We sought to identify a simple bedside method to predict successful extubation outcomes that might be used during rounds. We hypothesized that a direct 2-minute unassisted breathing evaluation (DTUBE) could replace a longer spontaneous breathing trial (SBT). Data were pro-spectively collected on all patients endotracheally intubated for >48 hours nearing extubation in a tertiary center's mixed trauma/surgical intensive care unit from August 2012 to August 2013. The SBT was performed for at least 30 minutes at 40 per cent FiO2, PEEP 5, and PS 8. DTUBE was performed by physically disconnecting the intubated patient from the ventilator circuit for a 2-minute period of direct observation on room air. Successful extubation was defined freedom from ventilator for greater than 72 hours. Both SBTand DTUBE were performed 128 times, resulting in 90 extubations. The DTUBE correctly predicted success in 75/79 (94.9%) extubations versus 82/89 (92.1%) via SBT. No adverse effects were directly attributed to the DTUBE. The DTUBE is a rapid method of evaluating patients for extubation with prediction accuracy similar to the SBT.

Ventilator Associated Pneumonia in Children

Ventilator associated pneumonia (VAP) is a common complication in mechanically ventilated children and adults. There remains much controversy in the literature over the definition, treatment and prevention of VAP. The incidence of VAP is variable, depending on the definition used and can effect up to 12% of ventilated children. For the prevention and reduction of the incidence of VAP, ventilation care bundles are suggested, which include vigorous hand hygiene, head elevation and use of non-invasive ventilation strategies. Diagnosis is mainly based on the clinical presentation with a lung infection occurring after 48hours of mechanical ventilation requiring a change in ventilator settings (mainly increased oxygen requirement, a positive culture of a specimen taken preferentially using a sterile sampling technique either using a bronchoscope or a blind lavage of the airways). A new infiltrate on a chest X ray supports the diagnosis of VAP. For the treatment of VAP, initial broad-spectrum antibiotics should be used followed by a specific antibiotic therapy with a narrow target once the bacterium is confirmed.

Swallowing dysfunction after critical illness

Critical care practitioners must frequently make decisions about their patients' ability to swallow food, liquids, and pills. These decisions can be particularly difficult given the incompletely defined epidemiology, diagnostic criteria, and prognostic features of swallowing disorders in critically ill patients. Furthermore, the consequences of improper decisions-namely, aspiration, malnutrition, hunger, and thirst-can be devastating to patients and their families. This review outlines the problem of swallowing dysfunction in critically ill patients and then addresses the most clinically relevant questions that critical care practitioners face today. First, we review the epidemiology of swallowing dysfunction in critically ill patients. Next, we describe the different diagnostic tests for swallowing dysfunction and describe a general approach to the initial assessment for swallowing disorders. Finally, we explore the existing treatments for swallowing dysfunction. Given the burden of swallowing dysfunction in patients recovering from critical illness, enabling critical care practitioners to manage these disorders, while stimulating new investigation into their pathophysiology, diagnosis, and management, will enhance our care of critically ill patients.

Micro-patterned surfaces reduce bacterial colonization and biofilm formation in vitro: Potential for enhancing endotracheal tube designs

Background

Ventilator-associated pneumonia (VAP) is a leading hospital acquired infection in intensive care units despite improved patient care practices and advancements in endotracheal tube (ETT) designs. The ETT provides a conduit for bacterial access to the lower respiratory tract and a substratum for biofilm formation, both of which lead to VAP. A novel microscopic ordered surface topography, the Sharklet micro-pattern, has been shown to decrease surface attachment of numerous microorganisms, and may provide an alternative strategy for VAP prevention if included on the surface of an ETT. To evaluate the feasibility of this micro-pattern for this application, the microbial range of performance was investigated in addition to biofilm studies with and without a mucin-rich medium to simulate the tracheal environment in vitro.

Methods

The top five pathogens associated with ETT-related pneumonia, Methicillin-Resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, Klebsiella pneumonia, Acinetobacter baumannii, and Escherichia coli, were evaluated for attachment to micro-patterned and un-patterned silicone surfaces in a short-term colonization assay. Two key pathogens, MRSA and Pseudomonas aeruginosa, were evaluated for biofilm formation in a nutrient rich broth for four days and minimal media for 24 hours, respectively, on each surface type. P. aeruginosa was further evaluated for biofilm formation on each surface type in a mucin-modified medium mimicking tracheal mucosal secretions. Results are reported as percent reductions and significance is based on t-tests and ANOVA models of log reductions. All experiments were replicated at least three times.

Results

Micro-patterned surfaces demonstrated reductions in microbial colonization for a broad range of species, with up to 99.9% (p < 0.05) reduction compared to un-patterned controls. Biofilm formation was also reduced, with 67% (p = 0.12) and 52% (p = 0.05) reductions in MRSA and P. aeruginosa biofilm formation, respectively. Further, a 58% (p < 0.01) reduction was demonstrated on micro-patterned surfaces for P. aeruginosa biofilms under clinically-simulated conditions when compared to un-patterned controls.

Conclusions

This engineered micro-pattern reduces the colonization and biofilm formation of key VAP-associated pathogens in vitro. Future application of this micro-pattern on endotracheal tubes may prevent or prolong the onset of VAP without the need for antimicrobial agents.

Duration of prehospital intubation is not a risk factor for development of early ventilator-associated pneumonia

PURPOSE

Ventilator-associated pneumonia (VAP) is a significant cause of morbidity and mortality among critically ill patients with trauma. Few VAP prevention strategies have been studied in the prehospital environment. The objectives of this study are to measure the association between duration of prehospital intubation and intubation location with subsequent incidence of early (within 5 days) VAP.

MATERIALS AND METHODS

Single-center retrospective cohort study of all intubated adult (age≥18 years) patients with trauma presenting to a 711-bed Midwestern Level I trauma center between January 2005 and December 2011 (n=860).

RESULTS

Thirty-five patients (6.4%) were diagnosed as having early VAP during the study period. Using multivariable logistic regression to adjust for age, injury severity score, and year (corresponding to VAP bundle implementation), the duration of intubation prior to hospital admission was not associated with subsequent diagnosis of VAP (adjusted odds ratio, 0.90 per hour; 95% confidence interval, 0.70-1.15). Location of intubation was similarly not associated with VAP.

CONCLUSIONS

Duration of prehospital intubation and intubation location were not different in patients with trauma who developed early VAP. Further prospective analyses should be conducted to better elucidate the effect of prehospital management on the development of traditionally in-hospital complications.

Activities of tobramycin and polymyxin E against Pseudomonas aeruginosa biofilm-coated medical grade endotracheal tubes

Indwelling medical devices have become a major source of nosocomial infections, especially Pseudomonas aeruginosa infections, which remain the most common cause of ventilator-associated pneumonia (VAP) in neonates and children. Using medical grade polyvinyl chloride endotracheal tubes (ETTs), the activity of tobramycin and polymyxin E was quantified in a simulated prevention and treatment static time-kill model using biofilm-forming P. aeruginosa. The model simulated three clinical conditions: (i) planktonic bacteria grown in the presence of antibiotics (tobramycin and polymyxin E) without ETTs, (ii) planktonic bacteria grown in the presence of P. aeruginosa, antibiotic, and ETTs (simulating prevention), and (iii) a 24-h-formed P. aeruginosa biofilm grown on ETTs prior to antibiotic exposure (simulating treatment). In the model simulating "prevention" (conditions 1 and 2 above), tobramycin alone or in combination with polymyxin E was more bactericidal than polymyxin E alone at 24 h using a concentration of greater than 2 times the MIC. However, after a 24-h-old biofilm was allowed to form on the ETTs, neither monotherapy nor combination therapy over 24 h exhibited bactericidal or bacteriostatic effects. Against the same pathogens, tobramycin and polymyxin E, alone or in combination, exhibited bactericidal activity prior to biofilm attachment to the ETTs; however, no activity was observed once biofilm formed on ETTs. These findings support surveillance culturing to identify pathogens for a rapid and targeted approach to therapy, especially when P. aeruginosa is a potential pathogen.

Ventilator-associated pneumonia, liver disease and oral chlorhexldine

As part of the ventilator care bundle, the Department of Health (DH) in the U.K. recommends the use of chlorhexidine (CHX) for oral care to prevent the occurrence of ventilator-associated pneumonia (VAP) in all mechanically ventilated patients. Due to the heterogenous nature of this population, however, it is important to consider whether such recommendations are also relevant to specific critical care patient population groups. This article reviews the available scientific evidence on the use of CHX in the prevention of VAP, with a focus on critically ill mechanically ventilated patients who have liver dysfunction. Findings will be discussed with reference to the wider research literature in order to make recommendations for future practice.

Biofilm-dependent airway infections: a role for ambroxol?

Biofilms are a key factor in the development of both acute and chronic airway infections. Their relevance is well established in ventilator associated pneumonia, one of the most severe complications in critically ill patients, and in cystic fibrosis, the most common lethal genetic disease in Caucasians. Accumulating evidence suggests that biofilms could have also a role in chronic obstructive pulmonary disease and their involvement in bronchiectasis has been proposed as well. When they grow in biofilms, microorganisms become multidrug-resistant. Therefore the treatment of biofilm-dependent airway infections is problematic. Indeed, it still largely based on measures aiming to prevent the formation of biofilms or remove them once that they are formed. Here we review recent evidence suggesting that the mucokinetic drug ambroxol has specific anti-biofilm properties. We also discuss how additional pharmacological properties of this drug could be beneficial in biofilm-dependent airway infections. Specifically, we review the evidence showing that: 1-ambroxol exerts anti-inflammatory effects by inhibiting at multiple levels the activity of neutrophils, and 2-it improves mucociliary clearance by interfering with the activity of airway epithelium ion channels and transporters including sodium/bicarbonate and sodium/potassium/chloride cotransporters, cystic fibrosis transmembrane conductance regulator and aquaporins. As a whole, the data that we review here suggest that ambroxol could be helpful in biofilm-dependent airway infections. However, considering the limited clinical evidence available up to date, further clinical studies are required to support the use of ambroxol in these diseases.

Oral hygiene care for critically ill patients to prevent ventilator-associated pneumonia

BACKGROUND

Ventilator-associated pneumonia (VAP) is defined as pneumonia developing in persons who have received mechanical ventilation for at least 48 hours. VAP is a potentially serious complication in these patients who are already critically ill. Oral hygiene care (OHC), using either a mouthrinse, gel, toothbrush, or combination, together with aspiration of secretions may reduce the risk of VAP in these patients.

OBJECTIVES

To assess the effects of OHC on the incidence of VAP in critically ill patients receiving mechanical ventilation in intensive care units (ICUs) in hospitals.

SEARCH METHODS

We searched the Cochrane Oral Health Group's Trials Register (to 14 January 2013), CENTRAL (The Cochrane Library 2012, Issue 12), MEDLINE (OVID) (1946 to 14 January 2013), EMBASE (OVID) (1980 to 14 January 2013), LILACS (BIREME) (1982 to 14 January 2013), CINAHL (EBSCO) (1980 to 14 January 2013), Chinese Biomedical Literature Database (1978 to 14 January 2013), China National Knowledge Infrastructure (1994 to 14 January 2013), Wan Fang Database (January 1984 to 14 January 2013), OpenGrey and ClinicalTrials.gov (to 14 January 2013). There were no restrictions regarding language or date of publication.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) evaluating the effects of OHC (mouthrinse, swab, toothbrush or combination) in critically ill patients receiving mechanical ventilation.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed all search results, extracted data and undertook risk of bias. We contacted study authors for additional information. Trials with similar interventions and outcomes were pooled reporting odds ratios (OR) for dichotomous outcomes and mean differences (MD) for continuous outcomes using random-effects models unless there were fewer than four studies.

MAIN RESULTS

Thirty-five RCTs (5374 participants) were included. Five trials (14%) were assessed at low risk of bias, 17 studies (49%) were at high risk of bias, and 13 studies (37%) were assessed at unclear risk of bias in at least one domain. There were four main comparisons: chlorhexidine (CHX mouthrinse or gel) versus placebo/usual care, toothbrushing versus no toothbrushing, powered versus manual toothbrushing and comparisons of oral care solutions.There is moderate quality evidence from 17 RCTs (2402 participants, two at high, 11 at unclear and four at low risk of bias) that CHX mouthrinse or gel, as part of OHC, compared to placebo or usual care is associated with a reduction in VAP (OR 0.60, 95% confidence intervals (CI) 0.47 to 0.77, P < 0.001, I(2) = 21%). This is equivalent to a number needed to treat (NNT) of 15 (95% CI 10 to 34) indicating that for every 15 ventilated patients in intensive care receiving OHC including chlorhexidine, one outcome of VAP will be prevented. There is no evidence of a difference between CHX and placebo/usual care in the outcomes of mortality (OR 1.10, 95% CI 0.87 to 1.38, P = 0.44, I(2) = 2%, 15 RCTs, moderate quality evidence), duration of mechanical ventilation (MD 0.09, 95% CI -0.84 to 1.01 days, P = 0.85, I(2) = 24%, six RCTs, moderate quality evidence), or duration of ICU stay (MD -0.21, 95% CI -1.48 to 1.89 days, P = 0.81, I(2) = 9%, six RCTs, moderate quality evidence). There was insufficient evidence to determine whether there is a difference between CHX and placebo/usual care in the outcomes of duration of use of systemic antibiotics, oral health indices, microbiological cultures, caregivers preferences or cost. Only three studies reported any adverse effects, and these were mild with similar frequency in CHX and control groups.From three trials of children aged from 0 to 15 years (342 participants, moderate quality evidence) there is no evidence of a difference between OHC with CHX and placebo for the outcomes of VAP (OR 1.07, 95% CI 0.65 to 1.77, P = 0.79, I(2) = 0%), or mortality (OR 0.73, 95% CI 0.41 to 1.30, P = 0.28, I(2) = 0%), and insufficient evidence to determine the effect on the outcomes of duration of ventilation, duration of ICU stay, use of systemic antibiotics, plaque index, microbiological cultures or adverse effects, in children.Based on four RCTs (828 participants, low quality evidence) there is no evidence of a difference between OHC including toothbrushing (± CHX) compared to OHC without toothbrushing (± CHX) for the outcome of VAP (OR 0.69, 95% CI 0.36 to 1.29, P = 0.24 , I(2) = 64%) and no evidence of a difference for mortality (OR 0.85, 95% CI 0.62 to 1.16, P = 0.31, I(2) = 0%, four RCTs, moderate quality evidence). There is insufficient evidence to determine whether there is a difference due to toothbrushing for the outcomes of duration of mechanical ventilation, duration of ICU stay, use of systemic antibiotics, oral health indices, microbiological cultures, adverse effects, caregivers preferences or cost.Only one trial compared use of a powered toothbrush with a manual toothbrush providing insufficient evidence to determine the effect on any of the outcomes of this review.A range of other oral care solutions were compared. There is some weak evidence that povidone iodine mouthrinse is more effective than saline in reducing VAP (OR 0.35, 95% CI 0.19 to 0.65, P = 0.0009, I(2) = 53%) (two studies, 206 participants, high risk of bias). Due to the variation in comparisons and outcomes among the trials in this group there is insufficient evidence concerning the effects of other oral care solutions on the outcomes of this review.

AUTHORS' CONCLUSIONS

Effective OHC is important for ventilated patients in intensive care. OHC that includes either chlorhexidine mouthwash or gel is associated with a 40% reduction in the odds of developing ventilator-associated pneumonia in critically ill adults. However, there is no evidence of a difference in the outcomes of mortality, duration of mechanical ventilation or duration of ICU stay. There is no evidence that OHC including both CHX and toothbrushing is different from OHC with CHX alone, and some weak evidence to suggest that povidone iodine mouthrinse is more effective than saline in reducing VAP. There is insufficient evidence to determine whether powered toothbrushing or other oral care solutions are effective in reducing VAP.

Toothbrushing for critically ill mechanically ventilated patients: a systematic review and meta-analysis of randomized trials evaluating ventilator-associated pneumonia

BACKGROUND

Oral care may decrease ventilator-associated pneumonia in the ICU. The objective of this review was to summarize and critically appraise randomized trials in mechanically ventilated patients in the ICU testing the effect of oral care strategies involving toothbrushing on ventilator-associated pneumonia.

SEARCH METHODS

We searched EMBASE, MEDLINE, and the Cochrane Controlled Trials Register and Database of Systematic Reviews from 1980 until March 2012, independently and in duplicate, as well as personal files and reference lists. In duplicate, articles were selected if they were randomized trials, enrolled adult critically ill patients, compared any kind of oral care involving toothbrushing with any other kind of oral care or control with or without toothbrushing, and examined ventilator-associated pneumonia. In duplicate, we abstracted trial characteristics and quality using the Cochrane risk of bias tool. The results were combined using a random effects model.

RESULTS

We included six trials enrolling 1,408 patients, five of which compared toothbrushing to usual oral care and one of which compared electric with manual toothbrushing. In four trials, there was a trend toward lower ventilator-associated pneumonia rates (risk ratio, 0.77; 95% confidence interval, 0.50-1.21; p = 0.26). This trend was also observed in one trial reporting fewer cases of ventilator-associated pneumonia per 1,000 ventilator days (20.68 vs. 25.89; p = 0.53) in patients receiving toothbrushing vs. no toothbrushing. The only trial with low risk of bias suggested that toothbrushing significantly reduced ventilator-associated pneumonia (risk ratio, 0.26; 95% confidence interval, 0.10-0.67; p = 0.006). Use of chlorhexidine antisepsis seems to attenuate the effect of toothbrushing on ventilator-associated pneumonia (p for the interaction = 0.02). One trial comparing electric vs. manual toothbrushing showed no difference in ventilator-associated pneumonia rates (risk ratio, 0.96; 95% confidence interval, 0.47-1.96; p = 0.91). Toothbrushing did not impact on length of ICU stay, or ICU or hospital mortality.

CONCLUSIONS

In intubated, mechanically ventilated critically ill patients, toothbrushing did not significantly reduce the risk of ventilator-associated pneumonia overall. Toothbrushing has no effect on mortality or length of stay. Electric and manual toothbrushing seem to have similar effects. More research is needed on this aspect of oral care to evaluate its potential to decrease ventilator-associated pneumonia.

Cytotoxicity of selenium nanoparticles in rat dermal fibroblasts

Background:

Ventilator-associated pneumonia is a deadly nosocomial infection caused by contaminated endotracheal tubes. It has been shown that polyvinyl chloride (PVC, the endotracheal tube substrate) coated with elemental selenium nanoparticles reduces bacterial adherence and proliferation on PVC by over 99%. However, it is not known if selenium nanoparticles elicit a cytotoxic effect in vitro. The purpose of this study was to investigate the cytotoxic effects of PVC coated with selenium nanoparticles on fibroblasts, which are mammalian cells central to endotracheal tube intubation.

Methods:

Different concentrations of selenium nanoparticles were precipitated onto the PVC surface by reduction of selenium salts using glutathione. Characterization of PVC coated with selenium nanoparticles was done by scanning electron microscopy, energy dispersive x-ray, and contact angle measurements. For the cytotoxicity experiments, fibroblasts were seeded at a density of 5000 cm² onto PVC coated with three different concentrations of selenium nanoparticles (high, medium, low) and incubated for 4 hours (adhesion) as well as for 24 hours and 72 hours (proliferation). The half-maximal inhibitory concentration (IC₅₀) value was determined after 72 hours using an ultrahigh concentration. MTT assays were used to assess cell viability at the indicated time points.

Results:

The three concentrations of selenium nanoparticles did not elicit a cytotoxic effect after 72 hours (P < 0.01, n = 3). It was found that the IC₅₀value was at the ultrahigh concentration of selenium nanoparticles. The nanoparticulate elemental selenium concentration previously shown to decrease the function of bacteria was shown not to cause a cytotoxic effect on fibroblasts in vitro.

Conclusion:

These findings demonstrate great selectivity between bacteria and healthy cells, and are a viable option for coating endotracheal tubes in order to prevent ventilator-associated pneumonia.