The Impact of Tracheal Intubation on Host Defenses and Risks for Nosocomial Pneumonia

Effect of taurine supplementation on preventing ventilator-associated pneumonia in pediatrics under mechanical ventilation, a randomized controlled double-blind clinical trial

Introduction

One of the most prevalent healthcare-associated infections in the pediatric intensive care unit is ventilator-associated pneumonia (VAP). VAP not only results in prolonged hospital and intensive care unit (ICU) stays but also imposes higher costs on patients and the healthcare system. Therefore, it is essential to implement preventive measures. The lung-protective properties of taurine are recognized, and this research focuses on assessing the impact of taurine supplementation in preventing VAP.

Method

This double-blind, randomized clinical trial was conducted at Namazi Hospital's PICUs. The study included pediatrics on mechanical ventilation for over 48 h. Patients were randomly divided into two groups: the taurine and placebo groups. Alongside the standard care, participants from both groups were administered taurine or placebo capsules (30 mg/kg. day) in divided doses from the day of PICU admission through PICU discharge. The incidence of VAP through clinical and laboratory evidence was considered the primary outcome.

Results

Seventy-seven patients were included in the study, with 38 in the taurine group and 39 in the placebo group. VAP incidence was 7.9% in the taurine group and 64.1% in the placebo group. Taurine significantly reduced the duration of mechanical ventilation, ICU and hospital stay, and inotrope duration. The occurrence of septic shock was lower in the taurine group at 5.3%. Stepwise logistic regression showed that placebo receipt was the only risk factor for VAP, with placebo recipients being 20.8 times more likely to develop VAP. (P < 0.0001, OR 20.8, 95% CI 6.11-97.93) Taurine treatment also significantly reduced inflammatory markers such as CRP, pro-calcitonin, and interleukin-6 compared to placebo.

Conclusion

Our results showed that taurine supplementation can reduce the incidence of VAP and the duration of mechanical ventilation, ICU, and hospital stay in critically ill pediatric patients.

Registration number of the clinical trial

This study received approval from the Iranian registry clinical trial, registered on 29 June 2023 (IRCT20120731010453N4, http://www.irct.ir/).

Analyzing the characteristics of respiratory microbiota after the placement of an airway stent for malignant central airway obstruction

Malignant central airway stenosis is treated with airway stent placement, but post-placement microbial characteristics remain unclear. We studied microbial features in 60 patients post-stent placement, focusing on changes during granulation tissue proliferation. Samples were collected before stent (N = 29), after stent on day 3 (N = 20), and after granulation tissue formation (AS-GTF, N = 43). Metagenomic sequencing showed significant respiratory tract microbiota changes with granulation tissue. The microbiota composition, dominated by Actinobacteria, Firmicutes, and Proteobacteria, was similar among the groups. At the species level, the AS-GTF group exhibited significant differences, with Peptostreptococcus stomatis and Achromobacter xylosoxidans enriched. Analysis based on tracheoesophageal fistula presence identified Tannerella forsythia and Stenotrophomonas maltophilia as the main differential species, enriched in the fistula subgroup. Viral and fungal detection showed Human gammaherpesvirus 4 and Candida albicans as the main species, respectively. These findings highlight microbiota changes after stent placement, potentially associated with granulation tissue proliferation, informing stent placement therapy and anti-infective treatment optimization.

IMPORTANCE

Malignant central airway stenosis is a life-threatening condition that can be effectively treated with airway stent placement. However, despite its clinical importance, the microbial characteristics of the respiratory tract following stent insertion remain poorly understood. This study addresses this gap by investigating the microbial features in patients with malignant central airway stenosis after stent placement, with a specific focus on microbial changes during granulation tissue proliferation. The findings reveal significant alterations in the diversity and structure of the respiratory tract microbiota following the placement of malignant central airway stents. Notably, certain bacterial species, including Peptostreptococcus stomatis and Achromobacter xylosoxidans, exhibit distinct patterns in the after-stent granulation tissue formation group. Additionally, the presence of tracheoesophageal fistula further influences the microbial composition. These insights provide valuable references for optimizing stent placement therapy and enhancing clinical anti-infective strategies.

A panoramic view of hospitalized young children in the metropolitan area of the valley of Mexico during COVID-19

Objectives

This work provides an overview of young children's (aged 0-9) infectious diseases epidemiology, by exploring the link between various comorbid conditions, COVID-19, and death rate.

Methods

Public data on hospitalized young children was obtained from national databases of the Mexican health care system from 2020-2022. Data included age, year of entry, gender, the time between admission to death (hospitalization time), date of death, comorbidities, and admissions to the intensive care unit. Children were separated into age groups and frequencies were calculated. Binary regression models were developed to determine the correlation of comorbidities and COVID-19 to death as calculated by odds ratios (OR).

Results

From 2020-2022, there were 11,815 hospitalizations among young children, of which 15.98% were due to COVID-19, 2.55% of hospitalizations resulted in fatalities from which 32.45% of deaths were COVID-19 related. The highest case-calculated fatality ratio of COVID-19 infected young children was estimated at 7.04% by early 2020, but dropped to 2.11% by the end of the second semester of 2022. The most frequent comorbidities associated with their hospitalization and death for the general population were intubation (OR: 17.967), pneumonia (OR: 2.263), diabetes (OR: 7.301), cardiovascular diseases (OR: 1.528) and COVID-19 (OR: 261). For the COVID-19-positive group, the most impactful comorbidities were intubation (OR: 20.232), pneumonia (OR: 3.057), and diabetes (OR: 12.824).

Conclusion

Children's hospitalizations and deaths were common during the pandemic; wherein major comorbidities played an important role. Therefore, effective comorbidity management and vaccination programs are essential to reduce hospitalizations and deaths among young children.

Clinical and microbiological characteristics of carbapenem-resistant Enterobacteriaceae causing post-operative central nervous system infections in China

OBJECTIVES

Postoperative central nervous system infections (PCNSIs) caused by carbapenem-resistant Enterobacteriaceae (CRE) frequently result in unfavourable outcomes. However, CRE PCNSIs have not been well described from a clinical and microbiological perspective.

METHODS

A total of 254 PCNSIs cases were included (January 2017 through June 2020), and clinical features were compared based on pathogenic classification. Cox regression analysis was performed to assess risk factors for mortality. Antibiotic susceptibility testing and whole genome sequencing were conducted on CRE isolates preserved. MLST, cgMLST, resistance genes and virulence genes were further analysed.

RESULTS

Among 254 PCNSI cases, 15.4% were caused by Enterobacteriaceae including 28 cases by CRE. The 28-day mortality rates for CRE, CSE and non-Enterobacteriaceae PCNSIs were 50.0%, 27.3%, and 7.4%, respectively. 42.9% (12/28) of the CRE PCNSIs patients achieved clinical cure, with 25.0% achieved microbiological clearance. ST11-KL64 carrying blaKPC-2 was dominant in CRE (17/23, 73.9%), and the 28-day mortality rate of its infection was 58.5%. Most CRKP carried rampA/rampA2 genes (17/23, 73.9%).

CONCLUSION

ST11-KL64 CRKP carrying blaKPC-2 dominated among CRE PCNSIs. Targeted anti-infective combination therapy based on ceftazidime/avibactam or amikacin, combined with intrathecal administration of amikacin, was found to be effective. These findings render a new insight into the clinical and microbiological landscape of CRE PCNSIs.

Placement of Temporary Left Ventricular Assist Device Using Monitored Anesthesia Care and Regional Anesthesia

Patients with advanced cardiogenic shock requiring mechanical circulatory support are uniquely susceptible to clinical deterioration. Limiting physiologic perturbations via avoidance of general anesthesia and endotracheal intubation by awake Impella 5.5 placement is safe and may represent a novel strategy in mechanical circulatory support initiation among patients in cardiogenic shock. (Level of Difficulty: Intermediate.).

Pediatric Cervicofacial Necrotizing Fasciitis-A Challenge for a Medical Team

Cervical necrotizing fasciitis is a very rare complication of a bacterial infection that can have a dental cause. This type of infection typically affects fascial plane, which has a poor blood supply and can affect soft tissue and cervical fascia and can spread quickly causing infection of mediastinum. Initially, in the first stage, the overlying tissues are unaffected, and this can delay diagnosis and surgical intervention. Incidence in children is extremely rare and can be frequently associated with various other general pathologies that decrease the immune system response. We present a case of a young 12-year-old boy diagnosed with this type of infection in the head and neck as a complication of a second inferior molar pericoronitis. The treatment and the management of the case was difficult not only due to the presence of the infection but also because of the prolonged intubation.

Antimicrobial resistance in patients with COVID-19: a systematic review and meta-analysis

BACKGROUND

Frequent use of antibiotics in patients with COVID-19 threatens to exacerbate antimicrobial resistance. We aimed to establish the prevalence and predictors of bacterial infections and antimicrobial resistance in patients with COVID-19.

METHODS

We did a systematic review and meta-analysis of studies of bacterial co-infections (identified within ≤48 h of presentation) and secondary infections (>48 h after presentation) in outpatients or hospitalised patients with COVID-19. We searched the WHO COVID-19 Research Database to identify cohort studies, case series, case-control trials, and randomised controlled trials with populations of at least 50 patients published in any language between Jan 1, 2019, and Dec 1, 2021. Reviews, editorials, letters, pre-prints, and conference proceedings were excluded, as were studies in which bacterial infection was not microbiologically confirmed (or confirmed via nasopharyngeal swab only). We screened titles and abstracts of papers identified by our search, and then assessed the full text of potentially relevant articles. We reported the pooled prevalence of bacterial infections and antimicrobial resistance by doing a random-effects meta-analysis and meta-regression. Our primary outcomes were the prevalence of bacterial co-infection and secondary infection, and the prevalence of antibiotic-resistant pathogens among patients with laboratory-confirmed COVID-19 and bacterial infections. The study protocol was registered with PROSPERO (CRD42021297344).

FINDINGS

We included 148 studies of 362  976 patients, which were done between December, 2019, and May, 2021. The prevalence of bacterial co-infection was 5·3% (95% CI 3·8-7·4), whereas the prevalence of secondary bacterial infection was 18·4% (14·0-23·7). 42 (28%) studies included comprehensive data for the prevalence of antimicrobial resistance among bacterial infections. Among people with bacterial infections, the proportion of infections that were resistant to antimicrobials was 60·8% (95% CI 38·6-79·3), and the proportion of isolates that were resistant was 37·5% (26·9-49·5). Heterogeneity in the reported prevalence of antimicrobial resistance in organisms was substantial (I2=95%).

INTERPRETATION

Although infrequently assessed, antimicrobial resistance is highly prevalent in patients with COVID-19 and bacterial infections. Future research and surveillance assessing the effect of COVID-19 on antimicrobial resistance at the patient and population level are urgently needed.

FUNDING

WHO.

High-flow nasal cannula improves hypoxemia in dogs failing conventional oxygen therapy

OBJECTIVE

A prospective clinical trial was performed to evaluate the efficacy and tolerance of high-flow nasal cannula (HFNC) in dogs with hypoxemia.

ANIMALS

20 client-owned dogs failing conventional oxygen therapy (COT).

PROCEDURES

Patients admitted to the ICU for treatment of hypoxemic respiratory failure were enrolled in the study. PaO2, SPO2, respiratory rate (RR), and acute patient physiologic and laboratory evaluation scores were obtained at the time of COT failure and after initiation of HFNC. Complications and patient tolerance while receiving HFNC were also recorded.

RESULTS

Compared to COT, the median PaO2 and SO2 were significantly higher when dogs were receiving HFNC (60.8 vs 135.6 mm Hg and 90.7% vs 99.25%, respectively). Dogs receiving HFNC had a significant reduction in median RR as compared to dogs undergoing COT (52 vs 36 breaths per minute). After the initiation of HFNC, all dogs showed clinical improvement as measured by PaO2, SO2, and RR. Of 20 dogs, 6 ultimately failed HFNC and mechanical ventilation was recommended. Nine dogs undergoing HFNC survived to discharge, and acute patient physiologic and laboratory evaluation scores had a significant positive severity correlation with death. Complications included pneumothorax in 1 dog.

CLINICAL RELEVANCE

COT has limited flow rates due to airway irritation caused by room temperature, nonhumidified oxygen. HFNC uses vapor humidification and heated oxygen, allowing for higher flow rates. In people, HFNC is used as escalation of oxygen therapy when COT fails. Dogs treated with HFNC had significant improvements in PaO2, SO2, and RR as compared to COT. HFNC is well tolerated and effective in treating hypoxemia in dogs.

Pathogen Species Is Associated With Mortality in Nosocomial Bloodstream Infection in Patients With COVID-19

Background

The epidemiology of nosocomial bloodstream infections (NBSIs) in patients with coronavirus disease 2019 (COVID-19) is poorly understood, due in part to substantial disease heterogeneity resulting from multiple potential pathogens.

Methods

We identified risk factors for NBSIs and examined the association between NBSIs and mortality in a retrospective cohort of patients hospitalized with COVID-19 in 2 New York City hospitals during the height of the pandemic. We adjusted for the potential effects of factors likely to confound that association, including age, race, illness severity upon admission, and underlying health status.

Results

Between January 1 and October 1, 2020, 1403 patients had a positive blood culture, and 79 and 101 met the stringent criteria for NBSI among non-COVID-19 and COVID-19 patients, respectively. NBSIs occurred almost exclusively among patients who were severely ill with COVID-19 at hospital admission. NBSIs were associated with elevated mortality, even after adjusting for baseline differences in COVID-19 illness (55% cases vs 45% controls; P = .13). Mortality was concentrated in patients with early-onset pneumonia caused by S. aureus and gram-negative bacteria. Less virulent Candida (49%) and Enterococcus (12%) species were the predominant cause of NBSI in the latter stages of hospitalization, after antibiotic treatment and COVID-19 treatments that attenuate immune response. Most Enterococcus and Candida infections did not have an identifiable source and were not associated with common risk factors for infection by these organisms.

Conclusions

Pathogen species and mortality exhibited temporal differences. Early recognition of risk factors among COVID-19 patients could potentially decrease NBSI-associated mortality through early COVID-19 and antimicrobial treatment.

Methicillin-Resistant Staphylococcus aureus Hospital-Acquired Pneumonia/Ventilator-Associated Pneumonia

Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP). MRSA pneumonia is associated with significant morbidity and mortality. Several virulence factors allow S. aureus to become an effective pathogen. The polysaccharide intracellular adhesin allows for the production of biofilms, some strains can produce capsular polysaccharides that protect against phagocytosis, microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) allow for colonization of epithelial surfaces, and S. aureus secretes several exotoxins that aid in tissue destruction. The α-hemolysin exotoxin secreted by S. aureus is one of the most important virulence factors for the bacteria. The diagnosis of MRSA pneumonia can be challenging; the infection may present as a mild respiratory infection or severe respiratory failure and septic shock. Many individuals are colonized with MRSA and thus a positive nasopharyngeal swab does not confirm infection in the lower respiratory tract. The management of MRSA pneumonia has evolved. Historically, vancomycin has been the primary antibiotic used to treat MRSA pneumonia. Over the past decade, prospective studies have shown that linezolid leads to higher rates of clinical cure. Monoclonal antibodies are being studied as potential therapeutic options. MRSA is an important cause of HAP/VAP; novel diagnostics may facilitate rapid diagnosis of this infection and the available literature should be used to make informed decisions on management.

Predictors and microbiology of respiratory and bloodstream bacterial infection in patients with COVID-19: living rapid review update and meta-regression

BACKGROUND

The prevalence of bacterial infection in patients with COVID-19 is low, however, empiric antibiotic use is high. Risk stratification may be needed to minimize unnecessary empiric antibiotic use.

OBJECTIVE

To identify risk factors and microbiology associated with respiratory and bloodstream bacterial infection in patients with COVID-19.

DATA SOURCES

We searched MEDLINE, OVID Epub and EMBASE for published literature up to 5 February 2021.

STUDY ELIGIBILITY CRITERIA

Studies including at least 50 patients with COVID-19 in any healthcare setting.

METHODS

We used a validated ten-item risk of bias tool for disease prevalence. The main outcome of interest was the proportion of COVID-19 patients with bloodstream and/or respiratory bacterial co-infection and secondary infection. We performed meta-regression to identify study population factors associated with bacterial infection including healthcare setting, age, comorbidities and COVID-19 medication.

RESULTS

Out of 33 345 studies screened, 171 were included in the final analysis. Bacterial infection data were available from 171 262 patients. The prevalence of co-infection was 5.1% (95% CI 3.6-7.1%) and secondary infection was 13.1% (95% CI 9.8-17.2%). There was a higher odds of bacterial infection in studies with a higher proportion of patients in the intensive care unit (ICU) (adjusted OR 18.8, 95% CI 6.5-54.8). Female sex was associated with a lower odds of secondary infection (adjusted OR 0.73, 95% CI 0.55-0.97) but not co-infection (adjusted OR 1.05, 95% CI 0.80-1.37). The most common organisms isolated included Staphylococcus aureus, coagulase-negative staphylococci and Klebsiella species.

CONCLUSIONS

While the odds of respiratory and bloodstream bacterial infection are low in patients with COVID-19, meta-regression revealed potential risk factors for infection, including ICU setting and mechanical ventilation. The risk for secondary infection is substantially greater than the risk for co-infection in patients with COVID-19. Understanding predictors of co-infection and secondary infection may help to support improved antibiotic stewardship in patients with COVID-19.

Respiratory setback associated with extubation failure in extremely preterm infants

BACKGROUND AND OBJECTIVES

Extubation failure in preterm infants is associated with an increased risk of mortality and morbidity. There is limited evidence to suggest if the increased morbidities are due to inherent differences among infants who fail or succeed; or whether these are due to a true respiratory setback among those who fail extubation. The aim of this study was to evaluate the respiratory status of infants who fail extubation and to assess the time taken for these infants to achieve pre-extubation respiratory status.

METHODS

This was a retrospective study of infants with birth weight ≤ 1250 g who were born between January 2009 and December 2016. Infants were eligible if they failed first elective extubation. Extubation failure was defined as need for re-intubation within 5 days of extubation. Ventilator settings, blood gas parameters, respiratory severity score (RSS), and ventilation index (VI) were used to assess the respiratory status of infants.

RESULTS

Out of 384 infants, 76% were successful and 24% failed extubation. Among those who failed extubation 91%, 77%, and 56% infants remained intubated at 24 h, 72 h, and 7 days, respectively. Respiratory status was worse at 24 and 72 h after re-intubation when compared to pre-extubation levels. The median times for RSS and VI to reach pre-extubation levels were 4 and 7 days, respectively.

CONCLUSION

Among preterm infants, failed elective extubation is associated with a significant setback in the respiratory status. Infants who fail an extubation attempt may not achieve pre-extubation respiratory status for many days after reintubation.

De novo lung biofabrication: clinical need, construction methods, and design strategy

Chronic lung disease is the 4th leading cause of death in the United States. Due to a shortage of donor lungs, alternative approaches to support failing, native lungs have been attempted, including mechanical ventilation and various forms of artificial lungs. However, each of these support methods causes significant complications when used for longer than a few days and are thus not capable of long-term support. For artificial lungs, complications arise due to interactions between the artificial materials of the device and the blood of the recipient. A potential new approach is the fabrication of lungs from biological materials, such that the gas exchange membranes provide a more biomimetic blood-contacting interface. Recent advancements with three-dimensional, soft-tissue biofabrication methods and the engineering of thin, basement membranes demonstrate the potential of fabricating a lung scaffold from extracellular matrix materials. This scaffold could then be seeded with endothelial and epithelial cells, matured within a bioreactor, and transplanted. In theory, this fully biological lung could provide improved, long-term biocompatibility relative to artificial lungs, but significant work is needed to perfect the organ design and construction methods. Like artificial lungs, biofabricated lungs do not need to follow the shape and structure of a native lung, allowing for simpler manufacture. However, various functional requirements must still be met, including stable, efficient gas exchange for a period of years. Design decisions depend on the disease state, how the organ is implanted, and the latest biofabrication methods available in a rapidly evolving field.

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.

Endotracheal intubation results in acute tracheal damage induced by mtDNA/TLR9/NF-κB activity

Tracheitis secondary to placement of an endotracheal tube (ETT) is characterized by neutrophil accumulation in the tracheal lumen, which is generally associated with epithelial damage. Mitochondrial DNA (mtDNA), has been implicated in systemic inflammation and organ dysfunction following trauma; however, less is known about the effects of a foreign body on local trauma and tissue damage. We hypothesized that tracheal damage secondary to the ETT will result in local release of mtDNA at sufficient levels to induce TLR9 and NF‐κB activation. In a swine model we compared the differences between uncoated, and chloroquine (CQ) and N‐acetylcysteine (NAC) coated ETTs as measured by tracheal lavage fluids (TLF) over a period of 6 h. The swine model allowed us to recreate human conditions. ETT presence was characterized by neutrophil activation, necrosis, and release of proinflammatory cytokines mediated by TLR9/NF‐κB induction. Amelioration of the tracheal damage was observed in the CQ and NAC coated ETT group as shown in tracheal tissue specimens and TLF. The role of TLR9/NF‐κB dependent activity was confirmed by HEK‐Blue hTLR9 reporter cell line analysis after coincubation with TLF specimens with predetermined concentrations of NAC or CQ alone or TLR9 inhibitory oligodeoxynucleotide (iODN). These findings indicate that therapeutic interventions aimed at preventing mtDNA/TLR9/NF‐κB activity may have benefits in prevention of acute tracheal damage.

Endotracheal tube-induced sore throat pain and inflammation is coupled to the release of mitochondrial DNA

In the absence of infection, the pathophysiology of endotracheal tube-induced sore throat pain is unclear. Activated neutrophils release elastase, reactive oxygen species, and inflammatory cytokines known to contribute to neuropathic pain. Sterile tissue injury can cause the release of damage-associated molecular patterns such as mitochondrial DNA that promote neutrophil activation. We hypothesized that endotracheal tube-induced sore throat pain is linked to mitochondrial DNA-mediated neutrophil inflammation. A nonrandomized prospective survey for sore throat pain was conducted in 31 patients who required short-term intubation and had no evidence of upper airway infection. Patterns of neutrophil abundance, activation, and mitochondrial DNA levels were analyzed in tracheal lavage fluid following intubation and prior to extubation. Thirteen of 31 patients reported sore throat pain. Sore throat patients had high neutrophilia with elevated adhesion molecule and TLR9 expression and constitutive reactive oxygen species generation. Tracheal lavage fluid from sore throat patients accumulated mitochondrial DNA and stimulated neutrophils to release mediators associated with pain in a TLR9- and DNAse-dependent fashion. Endotracheal tube-induced sore throat is linked to the release of mitochondrial DNA and can drive TLR9-mediated inflammatory responses by neutrophils reported to cause pain. Mitigating the effects of cell-free mitochondrial DNA may prove beneficial for the prevention of endotracheal tube-mediated sore throat pain.

Indications of early intubation for patients with inhalation injury

Aim

For patients with inhalation injury, the indications for early intubation are diverse. The purpose of this study was to identify the most reliable symptoms, physical findings, and medical examinations with which to determine the indications for early intubation in patients with inhalation injury.

Methods

We retrospectively collected patient data from medical records. Collected data included age, sex, burn size, symptoms, physical findings, carboxyhemoglobin levels (COHb), and bronchial wall thickness (BWT) determined from chest computed tomography images. We analyzed the relationships between these findings and the early intubation. We performed fiberoptic bronchoscopy in all patients, and analyzed the relationships between bronchoscopic severity and other findings.

Results

Of the 205 patients, 80 patients were diagnosed as having inhalation injury, and 34 patients were intubated. Burn size, facial burns, neck burns, use of accessory respiratory muscles, and COHb seemed to be related with intubation, whereas singed nasal hair was not. If the patients suffered ≥27% total body surface area burn and BWT ≥3.5 mm, the positive predictive value for early intubation was 1.00. If the patients suffered smaller cutaneous burn without neck burn, and their COHb <4.0%, the negative predictive value for early intubation was 0.97. Fiberoptic bronchoscopy findings from above the glottis were mainly related with patients’ symptoms. Findings from below the glottis were mainly related with BWT and COHb.

Conclusions

Patients’ symptoms, especially use of accessory respiratory muscles, are reliable, and BWT and COHb are also useful tools, for determining the indication for early intubation.

Ventilator-Associated Pneumonia: A Review

Ventilator-associated pneumonia is the most frequent intensive care unit (ICU)-related infection in patients requiring mechanical ventilation. In contrast to other ICU-related infections, which have a low mortality rate, the mortality rate for ventilator-associated pneumonia ranges from 20% to 50%. These clinically significant infections prolong duration of mechanical ventilation and ICU length of stay, underscoring the financial burden these infections impose on the health care system. The causes of ventilator-associated pneumonia are varied and differ across different patient populations and different types of ICUs. This varied presentation underscores the need for the intensivist treating the patient with ventilator-associated pneumonia to have a clear knowledge of the ambient microbiologic flora in their ICU. Prevention of this disease process is of paramount importance and requires a multifaceted approach. Once a diagnosis of ventilator-associated pneumonia is suspected, early broad-spectrum antibiotic administration decreases morbidity and mortality and should be based on knowledge of the sensitivities of common infecting organisms in the ICU. De-escalation of therapy, once final culture results are available, is necessary to minimize development of resistant pathogens. Duration of therapy should be based on the patient’s clinical response, and every effort should be made to minimize duration of therapy, thus further minimizing the risk of resistance.

The influence of stents on microbial colonization of the airway in children after slide tracheoplasty: a 14-year single-center experience

OBJECTIVES

This study describes the microbial colonization profile of the airway in children after slide tracheoplasty (STP) with and without stents, and compares colonization to children undergoing cardiothoracic surgical procedures without airway related disease.

METHODS

A 14-year retrospective single case note review was performed on patients undergoing STP and stent insertion. Nose and throat (NT) and bronchoalveolar lavage (BAL) specimens were analyzed for microbial profile and expressed as cumulative mean microorganisms per patient (MMP).

RESULTS

Forty-three patients (median age ± SD 15.02 ± 31.76 months) underwent STP and 141 patients underwent cardiothoracic but no airway surgery (median age ± SD 31.7 ± 47.2 months). Sixteen patients required a stent after STP. One-hundred seventy-two positive microbial specimens were identified. The predominant 6 microorganisms were (1) Staphylococcus aureus; (2) Pseudomonas aeruginosa; (3) Haemophilus influenzae not type B; (4) Coliforms; (5) Streptococcus pneumoniae; and (6) Candida Albicans, and accounted for 128 (74%) of all positive specimens found. Children with stents had more MMP compared to children without stents after STP [4.06 ± 2.38 and 2.04 ± 2.24 MMP (P < 0.001), respectively]. Both groups of children after STP had more MMP compared to the control group (P < 0.001). Children with stents had more microbial colonization of their lower respiratory tract compared to their upper respiratory tract (3.36 ± 2.02 and 1.36 ± 0.93 MMP (P < 0.01) respectively). Staphylococcus aureus colonization of the lower respiratory tract was significantly higher in children with stents compared to children without stents after STP [0.5 and 0.15 MMP (P < 0.05) respectively].

CONCLUSIONS

This study indicates airway surgery and the subsequent use of stents to be a significant risk factor for microbial colonization of the airway in children. More specifically airway stents appear to increase colonization in the distal airway, which appears unrelated to that of the upper respiratory tract.

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.

Role of topical antibiotic prophylaxis in prevention of bacterial translocation into upper trachea in nasally intubated patients undergoing tonsillectomies

INTRODUCTION

The human oropharynx and nasopharynx are home of different bacteria and fungi. The initial sterile endotracheal tube (ETT) transfers mechanically the bacteria from the nasopharynx and oropharynx to the sterile tracheobronchial tree. We investigated the efficacy of Neomycin-Bacitracin combination spray in the prevention of this bacterial translocation through its application over and inside the lumen of the endotracheal tubes preoperatively.

PATIENTS AND METHODS

Ninety patients aged (from 8 to 15 years) with ASA I and II were randomly assigned into 2 groups (45 patients for each): Group I; patients with naso-tracheal intubation which sprayed by placebo spray (Lidocaine) and group II; with naso-tracheal intubation that sprayed with antibiotic spray (combined Neomycin sulphate and Bacitracin) on the outside wall of the tube and inside its lumen. At the end of surgery and immediately after extubation, swabs were taken from the upper trachea using cotton tipped swab for bacterial growth. Inflammatory biomarkers were assessed preoperatively and postoperatively to detect any laboratory differences between both groups.

RESULTS

In the control group, all patients had heavy bacterial contamination and they were at either level 3 or 4 colony forming units. Thirty-two patients (71%) were at level 3 while 13 patients (29%) were at level 4. In the study group, there were 28 (62.2%) patients showed no bacterial growth, 15 (33.3%) patients were level 1, and 2 patients (4.4%) at level 2 colony forming units. There were no clinical differences between the 2 groups. Also, there was no significant difference between the 2 groups regarding to their postoperative body temperature although the inflammatory biomarkers were significantly higher in the control group.

CONCLUSION

Bacterial translocation by endotracheal intubation to the tracheobronchial tree could be prevented by local antibiotic spray application to outer and inner walls of the endotracheal tubes.

Ventilator-associated pneumonia: current status and future recommendations

OBJECTIVE

Ventilator-associated pneumonia (VAP) is a common hazardous complication in ICU patients. The aim of the current review is to give an update on the current status and future recommendations for VAP prevention.

METHODS

This article gives an updated review of the current literature on VAP. The first part briefly reviews pathogenesis and epidemiology while the second includes an in-depth review of evidence-based practice guidelines (EBPG) and new technologies developed for prevention of VAP.

RESULTS

VAP remains a frequent and costly complication of critical illness with a pooled relative risk of 9-27% and mortality of 25-50%. Strikingly, VAP adds an estimated cost of more than $40,000 to a typical hospital admission. An important aetiological mechanism of VAP is gross or micro-aspiration of oropharyngeal organisms around the cuff of the endotracheal tube (ETT) into the distal bronchi. Prevention of VAP is preferable. Preventative measures can be divided into two main groups: the implemen- tation of EBPGs and use of device-based technologies. EBPGs have been authored jointly by the American Thoracic Society and the Infectious Diseases Society of America. The Canadian Critical Care Trials group also published VAP Guidelines in 2008. Their recommendations are detailed in this review. The current device-based technologies include drainage of subglottic secretions, silver coated ETTs aiming to influence the internal bio-layer of the ETT, better sealing of the lower airways with ultrathin cuffs and loops for optimal cuff pressure control.

CONCLUSIONS

EBPG consensus includes: elevation of the head of the bed, use of daily "sedation vacations" and decontamination of the oropharynx. Technological solutions should aim to use the most comprehensive combination of subglottic suction of secretions, optimization of ETT cuff pressure and ultrathin cuffs. VAP is a type of hospital-acquired pneumonia that develops more than 48 h after endotracheal intubation. Its incidence is estimated to be 9-27%, with a mortality of 25-50% [Am J Respir Crit Care Med 171:388-416 (2005), Am J Med 85:499-506 (1988), Chest 122:2115-2121 (2002), Intensive Care Med 35:9-29 (2009)]. The most important target in VAP handling is its prevention. The aim of this article is to review the pathogenesis, epidemiology and the different strategies/technologies for prevention of VAP.

Tracheostomy and related host-pathogen interaction are associated with airway inflammation as characterized by tracheal aspirate analysis

In the last years an increasing number of subjects experienced respiratory failure and underwent tracheostomy. The aim of the present study was to analyze tracheal aspirates from the inflammatory point of view. Samples were collected from 38 consecutive tracheostomized patients: 13 COPD, 6 with neurologic disorders and 19 with other different causes of respiratory failure. We analyzed cells and soluble mediators related to inflammation and/or infection. We also compared results obtained in the tracheal aspirate of COPD patients with the same determination in the sputum of another group of non-tracheostomized COPD patients (n=41). Regardless of the underlying diagnosis, most of the samples were Pseudomonas aeruginosa positive and cells and soluble mediator did not differ. Treatment with steroids was associated with lower amount of total cells, neutrophils and lymphocytes, whereas treatment with antibiotics was not. Tracheal aspirate neutrophils correlated with PaCO(2) values; neutrophils and eosinophils correlated with their percentages in blood. As compared with sputa obtained from another group of culture-positive non-tracheostomized COPDs, tracheal aspirates showed similar cell count, proportions of inflammatory cells, and infection/inflammatory mediators. In conclusion tracheal aspirates presented high amounts of viable cells and soluble mediators independently to the cause of respiratory failure leading to tracheotomy and they represent suitable specimens to study infection/inflammation interactions.

Autoinducer production and quorum-sensing dependent phenotypes of Pseudomonas aeruginosa vary according to isolation site during colonization of intubated patients

BACKGROUND

Pseudomonas aeruginosa frequently colonizes and is responsible for severe ventilator-associated pneumonia in intubated patients. A quorum-sensing (QS) circuit, depending on the production of the two QS-signaling molecules (autoinducers, AIs) 3-oxo-C12-HSL and C4-HSL, regulates the production by P. aeruginosa of several virulence factors and is required for biofilm formation. Therefore QS-inhibition has been suggested as a new target for preventive and/or therapeutic strategies. However the precise role of QS during colonization and subsequent infections of intubated patients remains unclear.

RESULTS

We wondered whether QS is active during colonization of intubated patients, and whether P. aeruginosa isolates growing inside the biofilm covering the intubation devices and those resident in the lungs of colonized patients differ in their QS-dependent phenotypes. We collected the intubation devices of eight patients colonized by P. aeruginosa. We detected 3-oxo-C12-HSL on eight, and C4-HSL on six of these devices. In three of these patients we also obtained P. aeruginosa isolates from tracheal aspirates at the time of extubation (n = 18), as well as isolates from the intubation devices (n = 25). We genotyped these isolates, quantified their AIs production, and determined three QS-dependent phenotypes (adherence capacity, biofilm and elastase production). The production of 3-oxo-C12-HSL was consistently increased for isolates from the intubation devices, whereas the production of C4-HSL was significantly higher for isolates from tracheal aspirates. Isolates from tracheal aspirates produced significantly higher amounts of elastase but less biofilm, and had a marginally reduced adhesion capacity than isolates from the intubation devices. Levels of 3-oxo-C12-HSL and elastase production correlated statistically for tracheal intubation isolates, whereas levels of 3-oxo-C12-HSL production and adhesion ability, as well as biofilm production, correlated weakly amongst intubation device isolates.

CONCLUSION

Our findings demonstrate that autoinducers are produced during the colonization of intubated patients by P. aeruginosa. The microenvironment, in which P. aeruginosa grows, may select for bacteria with different capacities to produce autoinducers and certain QS-dependent phenotypes. QS-inhibition might therefore affect differently isolates growing inside the biofilm covering intubation devices and those resident in the lungs.

Ventilator-associated pneumonia and pressure ulcer prevention as targets for quality improvement in the ICU

The health care culture must change. Florence Nightingale wrote [8] "deep-rooted and universal is the conviction that to give a medicine is to be doing something, or rather everything and to give air, warmth, cleanliness etc. is to do nothing." Hygiene care practices and mobility activities are fundamental and independent care components in the nursing profession. When implemented using available evidence, they can significantly improve patient outcomes. It is time to claim and demonstrate the importance of consistent delivery of the fundamentals of basic nursing care. Interventional patient hygiene is an effective framework to ensure the the basics of nursing care are consistently applied to improve patient outcomes.

Development and persistence of antimicrobial resistance in Pseudomonas aeruginosa: a longitudinal observation in mechanically ventilated patients

Intubated patients frequently become colonized by Pseudomonas aeruginosa, which is subsequently responsible for ventilator-associated pneumonia. This pathogen readily acquires resistance against available antimicrobials. Depending on the resistance mechanism selected for, resistance might either be lost or persist after removal of the selective pressure. We investigated the rapidity of selection, as well as the persistence, of antimicrobial resistance and determined the underlying mechanisms. We selected 109 prospectively collected P. aeruginosa tracheal isolates from two patients based on their prolonged intubation and colonization periods, during which they had received carbapenem, fluoroquinolone (FQ), or combined beta-lactam-aminoglycoside therapies. We determined antimicrobial resistance phenotypes by susceptibility testing and used quantitative real-time PCR to measure the expression of resistance determinants. Within 10 days after the initiation of therapy, all treatment regimens selected resistant isolates. Resistance to beta-lactam and FQ was correlated with ampC and mexC gene expression levels, respectively, whereas imipenem resistance was attributable to decreased oprD expression. Combined beta-lactam-aminoglycoside resistance was associated with the appearance of small-colony variants. Imipenem and FQ resistance persisted for prolonged times once the selecting antimicrobial treatment had been discontinued. In contrast, resistance to beta-lactams disappeared rapidly after removal of the selective pressure, to reappear promptly upon renewed exposure. Our results suggest that resistant P. aeruginosa is selected in less than 10 days independently of the antimicrobial class. Different resistance mechanisms lead to the loss or persistence of resistance after the removal of the selecting agent. Even if resistant isolates are not evident upon culture, they may persist in the lung and can be rapidly reselected.

Tracheobronchitis in the Intensive Care Unit

Tracheobronchitis can be broadly defined as inflammation of the airways between the larynx and the bronchioles. Clinically, this syndrome is recognized by an increase in the volume and purulence of the lower respiratory tract secretions and is frequently associated with signs of variable airflow obstruction. In the intensive care unit (ICU), tracheobronchitis is a relatively common problem with an incidence as high as 10.6% [1]. Although tracheobronchitis is associated with a significantly longer length of ICU stay and a prolonged need for mechanical ventilation, it has not been shown to increase mortality. These outcomes can be improved through the use of antimicrobial agents [1].

Delayed extubation to nasal continuous positive airway pressure in the immature baboon model of bronchopulmonary dysplasia: lung clinical and pathological findings

OBJECTIVE

Using the 125-day baboon model of bronchopulmonary dysplasia treated with prenatal steroid and exogenous surfactant, we hypothesized that a delay of extubation from low tidal volume positive pressure ventilation to nasal continuous positive airway pressure at 5 days (delayed nasal continuous positive airway pressure group) would not induce more lung injury when compared with baboons aggressively weaned to nasal continuous positive airway pressure at 24 hours (early nasal continuous positive airway pressure group), because both received positive pressure ventilation.

METHODS AND RESULTS

After delivery by cesarean section at 125 days (term: 185 days), infants received 2 doses of Curosurf (Chiesi Farmaceutica S.p.A., Parma, Italy) and daily caffeine citrate. The delay in extubation to 5 days resulted in baboons in the delayed nasal continuous positive airway pressure group having a lower arterial to alveolar oxygen ratio, high PaCO2, and worse respiratory function. The animals in the delayed nasal continuous positive airway pressure group exhibited a poor respiratory drive that contributed to more reintubations and time on mechanical ventilation. A few animals in both groups developed necrotizing enterocolitis and/or sepsis, but infectious pneumonias were not documented. Cellular bronchiolitis and peribronchiolar alveolar wall thickening were more frequently seen in the delayed nasal continuous positive airway pressure group. Bronchoalveolar lavage levels of interleukin-6, interleukin-8, monocyte chemotactic protein-1, macrophage inflammatory protein-1 alpha, and growth-regulated oncogene-alpha were significantly increased in the delayed nasal continuous positive airway pressure group. Standard and digital morphometric analyses showed no significant differences in internal surface area and nodal measurements between the groups. Platelet endothelial cell adhesion molecule vascular staining was not significantly different between the 2 nasal continuous positive airway pressure groups.

CONCLUSIONS

Volutrauma and/or low-grade colonization of airways secondary to increased reintubations and ventilation times are speculated to play causative roles in the delayed nasal continuous positive airway pressure group findings.

Involvement of periodontopathic anaerobes in aspiration pneumonia

Increasing evidence has linked the anaerobic bacteria forming periodontopathic biofilms with aspiration pneumonia in elderly persons. In experiments designed to eliminate the potent respiratory pathogens forming biofilms in the oral cavity, we have shown that the mechanical and chemical oral cleansing using povidone-iodine effectively reduced the detection rates and numbers of methicillin-sensitive Staphylococcus species, Streptococcus pneumoniae, and Haemophilus influenzae in patients scheduled to undergo oral surgery requiring endotracheal intubation. We confirmed the pathogenicity of periodontopathic anaerobic bacteria for aspiration pneumonia in an experimental mouse model. Based upon the finding of the coexistence of Porphyromonas gingivalis with Treponema denticola in chronic periodontitis lesions, we innoculated a mixed culture of P. gingivalis and T. denticola into the mouse trachea; the resulting infection induced inflammatory cytokine production and caused pneumonia. In another series of investigations, professional oral health care (POHC), mainly cleansing administered by dental hygienists once a week for 24 months to elderly persons requiring daily care, resulted in the reduction of the number of total anaerobes, Candida albicans, and Staphylococcus species and in the number of cases of fatal aspiration pneumonia. We also found that the POHC treatment of elderly persons for 6 months in the winter season reduced the salivary levels of protease, trypsin-like activity, and neuraminidase and also decreased the frequency of influenza cases.

Noninvasive ventilation in childhood acute neuromuscular respiratory failure: a pilot study

BACKGROUND

Over a 36-month study period, 10 nonconsecutive neuromuscular pediatric patients (6 infants, mean age 10.16 months, and 4 children, mean age 9.3 years) presenting with acute respiratory failure (ARF) were treated by noninvasive positive pressure ventilation (NPPV). All patients required immediate respiratory support and fulfilled our intubation criteria.

OBJECTIVE

The aim of the study was to verify if early NPPV was able to avoid endotracheal intubation and to improve both oxygenation and ventilation within 24 h from admission in this clinical setting.

PATIENTS AND METHODS

A prospective pilot study was carried out on neuromuscular patients admitted to the pediatric intensive care unit (PICU) of the Catholic University of Rome because of ARF and managed exclusively with NPPV for at least 24 h following admission. All patients were treated using a flow-triggered mechanical ventilator through a face mask or using the new helmet interface.

RESULTS

Eight patients were successfully ventilated during the observation period and 2 early failures occurred. Among children undergoing face mask NPPV, the PaO(2)/FiO(2) ratio increased from a median value of 75 (range 48-149) to 240 (range 133-385; p < 0.001) and 328 (range 180-371; p < 0.001) at selected time points (3 and 12 h after NPPV introduction, respectively); the alveolar-to-arterial oxygenation difference showed a similar trend, i.e. decreasing from a median value of 589 (range 213-659) to 128 (range 62-527; p < 0.01) and 69 (range 45-207; p < 0.001), respectively. Hypercarbic ARF resolved within 6 h from admission even in the most severe cases.

CONCLUSIONS

NPPV was a safe and effective first-line therapeutic approach in hypoxemic ARF children/infants with neuromuscular disease. It seems of importance to identify children with neuromuscular disorders who may be able to achieve residual ventilator-free breathing and to perform an NPPV trial avoiding tracheal intubation. Life-threatening respiratory distress and very young age should not preclude NPPV application in the PICU setting. The new helmet interface represents a promising tool for noninvasive ventilation in older children.

Conscious Cardiac Surgery With Cardiopulmonary Bypass Using Thoracic Epidural Anesthesia Without Endotracheal General Anesthesia

OBJECTIVE

The purpose of this study was to evaluate the feasibility of thoracic epidural anesthesia as an alternative technique to general anesthesia in patients undergoing cardiac surgery under cardiopulmonary bypass.

DESIGN

A prospective study.

SETTING

Tertiary referral heart hospital.

PARTICIPANTS

Eleven patients underwent cardiac surgical procedures requiring cardiopulmonary bypass under thoracic epidural anesthesia from February to April 2004.

INTERVENTIONS

An epidural catheter was inserted at C7 to T2 intervertebral space on the day before the operation. Subsequently, cardiac surgery was performed using cardiopulmonary bypass.

MEASUREMENTS AND RESULTS

The midsternotomy approach was used in all the patients. Anticoagulation was achieved with 300 units/kg of heparin. Under normothermic cardiopulmonary bypass, 6 patients underwent closure of atrial septal defect, 3 underwent valve replacements, and 2 underwent coronary artery bypass surgery combined with valve replacements. Soon after establishing cardiopulmonary bypass, all but 1 patient developed apnea, which was reversed after termination of cardiopulmonary bypass. The mean cardiopulmonary bypass time was 102 +/- 28 minutes, the aortic cross-clamp time was 58 +/- 28 minutes, and the total duration of surgery was 229 +/- 64 minutes. There was no mortality or morbidity in this series.

CONCLUSION

Cardiac surgical procedures requiring cardiopulmonary bypass may be performed under thoracic epidural anesthesia, without endotracheal general anesthesia.

Gargling with povidone-iodine reduces the transport of bacteria during oral intubation

PURPOSE

Nosocomial pneumonia remains a common complication in patients undergoing endotracheal intubation. This study examined the transport of bacteria into the trachea during endotracheal intubation, and evaluated the effects of gargling with povidone-iodine on bacterial contamination of the tip of the intubation tube.

METHODS

In the gargling group, patients gargled with 25 mL of povidone-iodine (2.5 mg.mL(-1)). In the control group, patients gargled with 25 mL of tap water. Before tracheal intubation, microorganisms were obtained from the posterior wall of the patient's pharynx using sterile cotton swabs. After anesthesia, all patients were extubated and bacteria contaminating the tip of the tracheal tube were sampled and cultured.

RESULTS

Before orotracheal intubation, all 19 patients who gargled with tap water (control group) had bacterial colonization on the posterior walls of the pharynx. This group included five patients who had methicillin-resistant staphylococcus aureus (MRSA) in their nasal cavity preoperatively and MRSA was also detected in the pharynx of four patients. Bacterial colonization was observed in all 19 patients who gargled with povidone-iodine (gargling group) and four patients carried MRSA in their nasal cavity, although no MRSA was detected in the pharynx. In the control group, all the patients had bacterial colonization at the tip of the tube after extubation. Additionally, MRSA was detected in two of the four patients. In the gargling group, povidone-iodine eradicated general bacteria and MRSA colonies in the pharynx before intubation and at the tip of the tube after extubation.

CONCLUSION

Gargling with povidone-iodine before oral intubation reduces the transport of bacteria into the trachea.

Prevention and Treatment of Aspiration Pneumonia in Intensive Care Units

Aspiration is a leading cause of nosocomial infection in the intensive care unit. Techniques to avoid or reduce aspiration are important in preventing pneumonia and pneumonitis. The most important preventive measures include the semi-recumbent position, the surveillance of enteral feeding, the use of promotility agents, and avoiding excessive sedation. The analysis of the pathogens involved in these syndromes usually shows a minor role for the anerobes. With regard to treatment, aspiration pneumonitis does not require any antimicrobials; on the contrary, aspiration pneumonia has to be treated. Empiric antimicrobials treatment should be started on clinical suspicion. The choice of the drug has to be guided by local pathogen epidemiology and clinical features; in fact, community type pneumonia requires a first-line antimicrobial such as amoxicillin/clavulanic acid. On the contrary, a nosocomial type of infection needs to be treated as a ventilator-associated pneumonia in agreement with published guidelines. Nevertheless, quantitative culture should be obtained in order to de-escalate antimicrobials. In conclusion, aspiration pneumonia is a frequently encountered disease that can be prevented by relatively simple measures.

Self-generated diversity produces "insurance effects" in biofilm communities

Diversity generally protects communities from unstable environmental conditions. This principle, known as the "insurance hypothesis," has been tested in many different ecosystems. Here we show that the opportunistic pathogen Pseudomonas aeruginosa undergoes extensive genetic diversification during short-term growth in biofilm communities. The induced genetic changes are produced by a recA-dependent mechanism and affect multiple traits, including the behavior of the bacteria in biofilms. Some biofilm-derived variants exhibit an increased ability to disseminate, whereas others manifest accelerated biofilm formation. Furthermore, the presence of these functionally diverse bacteria increases the ability of biofilms to resist an environmental stress. These findings suggest that self-generated diversity in biofilms provides a form of biological insurance that can safeguard the community in the face of adverse conditions.

Preventing ventilator-associated pneumonia: evidence-based care

Ventilator-associated pneumonia is a common complication of mechanical ventilation with significant morbidity and mortality. This article summarizes the data related to specific risk factors associated with ventilator associated pneumonia (patient position, oral health, airway management, and gastrointestinal factors) and provides recommendations for practice based on the present evidence.

Characterization of cell-to-cell signaling-deficient Pseudomonas aeruginosa strains colonizing intubated patients

Cell-to-cell signaling involving N-acyl-homoserine lactone compounds termed autoinducers (AIs) is instrumental to virulence factor production and biofilm development by Pseudomonas aeruginosa. In order to determine the importance of cell-to-cell signaling during the colonization of mechanically ventilated patients, we collected 442 P. aeruginosa pulmonary isolates from 13 patients. Phenotypic characterization showed that 81% of these isolates produced the AI-dependent virulence factors elastase, protease, and rhamnolipids. We identified nine genotypically distinct P. aeruginosa strains. Six of these strains produced AIs [N-butanoyl-homoserine lactone or N-(3-oxo-dodecanoyl)-homoserine lactone] and extracellular virulence factors (elastase, total exoprotease, rhamnolipid, hydrogen cyanide, or pyocyanin) in vitro. Three of the nine strains were defective in the production of both AIs and extracellular virulence factors. Two of these strains had mutational defects in both the lasR and rhlR genes, which encode the N-acyl-homoserine lactone-dependent transcriptional regulators LasR and RhlR, respectively. The third of these AI-deficient strains was only mutated in the lasR gene. Our observations suggest that most, but not all, strains colonizing intubated patients are able to produce virulence factors and that mutations affecting the cell-to-cell signaling circuit are preferentially located in the transcriptional regulator genes.

Long-term care of the tracheostomy patient

Care of the long-term tracheostomy patient is changing. By moving the initiation of tracheostomy out of the operating room and shifting responsibility for the procedure to the medical specialist, more patients are undergoing tracheostomy for a wider spectrum of diagnoses. With much of the aftercare now directed by the medical specialist, successful reintegration of the long-term tracheostomy patient into a productive life is dependent upon the collaborative care of several disciplines directed by the specialist. To effectively care for these challenging patients, it is critical for the physician who performs tracheostomy to be aware of the new caregiving role that is now theirs.

Nosocomial pneumonia in pediatric patients: practical problems and rational solutions

Nosocomial pneumonia is a common hospital-acquired infection in children, and is often fatal. Risk factors for nosocomial pneumonia include admission to an intensive care unit, intubation, burns, surgery, and underlying chronic illness. Viruses, predominantly respiratory syncytial virus (RSV), are the most common cause of pediatric nosocomial respiratory tract infections. Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa) are the predominant bacterial pathogens, and are associated with a high mortality rate. Staphylococcus aureus and Staphylococcus epidermidis are the most common Gram-positive bacteria causing nosocomial pneumonia; infections with these organisms have a better outcome than those with Gram-negative organisms. An increasing problem is the emergence of multiresistant Gram-positive and Gram-negative nosocomial pathogens. Distinguishing nosocomial pneumonia from other pulmonary processes may be difficult; diagnosis is based on clinical signs, radiological findings, and microbiological results. Recommended empiric therapy should consider factors such as the time of onset of illness, severity of disease, and specific risk factors for nosocomial pneumonia, including use of mechanical ventilation, underlying disease, or recent use of antibacterials. The resident local hospital flora should be considered when selecting therapy for nosocomial pneumonia. Early initiation of appropriate empiric therapy reduces morbidity and mortality. For empiric treatment of bacterial nosocomial pneumonia, an intravenous antibacterial regimen that includes coverage of Gram-negative bacilli and Gram-positive organisms should be used. A carbapenem or ureidopenicillin derivative (piperacillin) plus a beta-lactamase inhibitor should be used where extended spectrum beta-lactamase-producing Enterobacteriaceae are endemic. Therapy should be modified when a specific pathogen and its antimicrobial susceptibility are identified. Effective prevention of nosocomial pneumonia requires infection control measures that affect the environment, personnel, and patients. Of these, hand hygiene, appropriate infection control policies, and judicious use of antibacterials are essential.

Risk factors for nosocomial pneumonia in critically ill trauma patients

OBJECTIVE

To determine risk factors for nosocomial pneumonia in critically ill trauma patients.

DESIGN

Prospective cohort study.

SETTING

The trauma intensive care unit (ICU) of a 1500-bed tertiary-care hospital.

PATIENTS

All critically ill trauma patients (n = 103) admitted consecutively between November 1995 and October 1996.

INTERVENTIONS

A comparison of data recorded at the time of ICU admission and during the clinical evolution in patients with (n = 23) and without (n = 80) nosocomial pneumonia was made. Data referred mainly to possible risk factors were recorded; they also included factors related to pneumonia etiology and evolutive factors. Predictors of nosocomial pneumonia were assessed by logistic regression analysis.

MEASUREMENTS AND MAIN RESULTS

The presence of significant growth on quantitative cultures of the protected specimen brush (> or = 103 colony forming units/mL) was required to accept pneumonia as microbiologically proven, as well as the concurrence of a cohort of clinical and radiologic signs. Twenty-three (22.3%) patients developed nosocomial pneumonia. The mean age of these patients was 41.7 yrs; 18 of them (78.3%) were men. The microorganisms isolated in significant concentrations were Acinetobacter baumanii (ten cases), Staphylococcus aureus (11 cases), Pseudomonas aeruginosa (five cases), Haemophilus influenzae (two cases), and Klebsiella pneumoniae, Citrobacter freundii, Serratia marcescens, Enterococcus spp., Enterobacter spp., coagulase-negative Staphylococcus, and Streptococcus intermedius (one case each one). Risk factors for pneumonia by univariate analysis included nasogastric tube; continuous enteral feeding; prolonged mechanical ventilation (>1 day); use of H2-receptor antagonist, sucralfate, muscle relaxants, corticosteroids, barbiturates, and inotropic agents; positive end-expiratory pressure; intense sedation; re-intubation; tracheotomy; urgent brain computed tomography (CT) scan; craniotomy; iatrogenic event; and hyperventilation. The mortality rate was 43.5% (10 of 23) in the nosocomial pneumonia group and 18.8% in patients without nosocomial pneumonia (p =.02). Also, the mean stay in the ICU, the therapeutic charge (measured with total and mean punctuation of the Therapeutic Intervention Scoring System) and the complications, infectious and noninfectious, of the clinical evolution were significantly more frequent in patients with nosocomial pneumonia than in those without pneumonia (p <.05). In the multivariate analysis, continuous enteral feeding, craniotomy, prolonged mechanical ventilation (>24 hrs), use of positive end-expiratory pressure, and corticotherapy were independent predictors of nosocomial pneumonia.

CONCLUSIONS

It seems that factors related to the patient's clinical course, rather than variables registered on the first days of ICU admission, are those that would exert an influence on the development of nosocomial pneumonia in critically ill trauma patients. In this way, from our point of view, in our study the main risk factors are the use of prolonged mechanical ventilation (>4 hrs) and positive end-expiratory pressure. At the same time, we can conclude that the reduction of this infection incidence could decrease the mean stay in the ICU, the therapeutic charge, and the prognosis in terms of mortality and morbidity.

Assessing the need for reintubation: a prospective evaluation of unplanned endotracheal extubation

OBJECTIVE

Unplanned endotracheal extubation (UEE) is a common complication in medical intensive care units but very little data about UEE in surgical populations are available. Our hypothesis is that the surgical intensive care unit (SICU) population requires reintubation less frequently compared with the medical intensive care unit population. We prospectively gathered data on patients in a SICU in an attempt to identify the incidence of UEE and to study the need for reintubation after UEE.

METHODS

During an 18-month period, we prospectively identified SICU patients from a quality improvement database who required ventilatory support. All patients who self-extubated were included in the study.

RESULTS

Fifty-eight of 1,178 intubated patients experienced unplanned extubation 61 times during the 18-month period. A total of 22 patients (36%) required reintubation, whereas 39 patients (64%) did not. Thirty-three patients self-extubated while being actively weaned from ventilatory support. Of these, only 5 patients (15%) required reintubation and 28 patients (85%) did not (p < 0.01).

CONCLUSION

A total of 85% of patients who self-extubate during the weaning process did not require reintubation in our study. Those who have an FiO2 >50%, a lower PaO2/FiO2 ratio, had UEE occur by accident, or were not being weaned when UEE occurred required reintubation more frequently. These data suggest that some of our SICU patients are intubated longer than necessary, which may translate into more ventilator related complications, longer ICU stays and increased cost.

Incidence of gastroesophageal reflux and aspiration in mechanically ventilated patients using small-bore nasogastric tubes

BACKGROUND

Use of a large-bore nasogastric tube (NGT) and patient position are considered key factors in promoting gastroesophageal reflux (GER) and pulmonary aspiration in critically ill patients. The objective of this study was to determine the incidence of GER and pulmonary aspiration of gastric contents in mechanically ventilated (MV) patients using small-bore NGTs.

METHODS

We studied 30 patients on mechanical ventilation for acute respiratory failure who tolerated enteral nutrition through a small-bore NGT. Patients were randomly assigned to a group with (n = 16) or without (n = 14) a small-bore NGT and were maintained in a semirecumbent position during the study. GER and aspiration of gastric contents were assessed by a radioisotopic technique. Scans were done 24 hours after technetium-99m administration (n = 30). In 9 patients a dynamic scintigraphy was performed immediately after colloid administration, and samples of blood and tracheal and oropharyngeal secretions were obtained basally, 30 minutes, and 24 hours after technetium administration and analyzed for radioactivity using a gamma counter.

RESULTS

Both groups were similar in age, underlying diagnosis, number of days of mechanical ventilation at the day of study, and mortality. There were no GER reaching the oropharynx and aspiration of gastric contents in both groups.

CONCLUSIONS

GER and aspiration of gastric contents were not detected in MV patients using small-bore NGTs and may be a simple measure to prevent ventilator-associated pneumonia.