Inhaled Amikacin to Prevent Ventilator-Associated Pneumonia

Precise antibiotic delivery to the lung infection microenvironment boosts the treatment of pneumonia with decreased gut dysbiosis

Bacterial pneumonia is a common disease with significant health risks. However, the overuse antibiotics in clinics face challenges such as inadequate targeting and limited drug utilization, leading to drug resistance and gut dysbiosis. Herein, a dual-responsive lung inflammatory tissue targeted nanoparticle (LITTN), designed for targeting lung tissue and bacteria, is screened from a series of prepared nanoparticles consisting of permanent cationic lipids, acid-responsive lipids, and reactive oxygen species-responsive and phenylboronic acid-modified lipids with different surface properties. Such nanoparticle is further verified to enhance the adsorption of vitronectin in serum. Additionally, the optimized nanoparticle exhibits more positive charge and coordination of boric acid with cis-diol in the infected microenvironment, facilitating electrostatic interactions with bacteria and biofilm penetration. Importantly, the antibacterial efficiency of dual-responsive rifampicin-loaded LITTN (Rif@LITTN) against methicillin-resistant staphylococcus aureus is 10 times higher than that of free rifampicin. In a mouse model of bacterial pneumonia, the intravenous administration of Rif@LITTN could precisely target the lungs, localize in the lung infection microenvironment, and trigger the responsive release of rifampicin, thereby effectively alleviating lung inflammation and reducing damage. Notably, the targeted delivery of rifampicin helps protect against antibiotic-induced changes in the gut microbiota. This study establishes a new strategy for precise delivery to the lung-infected microenvironment, promoting treatment efficacy while minimizing the impact on gut microbiota. STATEMENT OF SIGNIFICANCE: Intravenous antibiotics play a critical role in clinical care, particularly for severe bacterial pneumonia. However, the inability of antibiotics to reach target tissues causes serious side effects, including liver and kidney damage and intestinal dysbiosis. Therefore, achieving precise delivery of antibiotics is of great significance. In this study, we developed a novel lung inflammatory tissue-targeted nanoparticle that could target lung tissue after intravenous administration and then target the inflammatory microenvironment to trigger dual-responsive antibiotics release to synergistically treat pneumonia while maintaining the balance of gut microbiota and reducing the adverse effects of antibiotics. This study provides new ideas for targeted drug delivery and reference for clinical treatment of pneumonia.

The efficacy and safety of inhaled antibiotics for pneumonia: A systematic review and meta-analysis

OBJECTIVES

The aim of this study was to evaluate the efficacy and safety of inhaled antibiotics for adults with pneumonia by meta-analysis.

METHODS

Literature retrieval was completed through five databases (PubMed, Embase, Cochrane Library, Web of Science and Scopus) by the deadline of May 31, 2024. The process of study selection and data extraction were performed independently by two reviewers. The quality of observational studies and randomized controlled trial (RCT) studies were evaluated by Newcastle Ottawa scale and Jadad scale, respectively. The primary outcomes included mortality, clinical cure, and microbiological cure. Secondary outcomes were recurrence and renal impairment.

RESULTS

There were 30 studies were analyzed, including 12 RCT studies and 18 observational studies. Inhaled antibiotics did not significantly reduce mortality in RCT studies (odds ratio (OR) = 1.06, 95 % confidence interval (CI): 0.80-1.41). Inhaled antibiotics were associated with higher rates of clinical cure (OR = 1.47 95%CI: 0.82-2.66 in RCT studies and OR = 2.09, 95%CI: 1.36-3.21 in observational studies) and microbiological cure (OR = 7.00 in RCT studies and OR = 2.20 in observational studies). Subgroup analysis showed patients received inhaled antibiotics combined with intravenous administration and inhaled amikacin had better improvements of mortality, clinical cure and microbiological cure. Inhaled antibiotics were not associated with recurrence. The pooled OR of renal impairment were 0.65 (95%CI: 0.27-1.13; I-squared = 43.5 %, P = 0.124) and 0.63(95%CI: 0.26-1.11; I-squared = 69.0 %, P = 0.110) in RCT studies and observational studies, respectively.

CONCLUSIONS

Inhaled antibiotics decreased risk of renal impairment and achieved significant improvements of clinical and microbiological cure in patients with pneumoniae.

Subgroup analyses and heterogeneity of treatment effects in randomized trials: a primer for the clinician

PURPOSE OF REVIEW

To date, most randomized clinical trials in critical care report neutral overall results. However, research as to whether heterogenous responses underlie these results and give opportunity for personalized care is gaining momentum but has yet to inform clinical practice guidance. Thus, we aim to provide an overview of methodological approaches to estimating heterogeneity of treatment effects in randomized trials and conjecture about future paths to application in patient care.

RECENT FINDINGS

Despite their limitations, traditional subgroup analyses are still the most reported approach. More recent methods based on subphenotyping, risk modeling and effect modeling are still uncommonly embedded in primary reports of clinical trials but have provided useful insights in secondary analyses. However, further simulation studies and subsequent guidelines are needed to ascertain the most efficient and robust manner to validate these results for eventual use in practice.

SUMMARY

There is an increasing interest in approaches that can identify heterogeneity in treatment effects from randomized clinical trials, extending beyond traditional subgroup analyses. While prospective validation in further studies is still needed, these approaches are promising tools for design, interpretation, and implementation of clinical trial results.

Understanding antimicrobial pharmacokinetics in critically ill patients to optimize antimicrobial therapy: A narrative review

Effective treatment of sepsis not only demands prompt administration of appropriate antimicrobials but also requires precise dosing to enhance the likelihood of patient survival. Adequate dosing refers to the administration of doses that yield therapeutic drug concentrations at the infection site. This ensures a favorable clinical and microbiological response while avoiding antibiotic-related toxicity. Therapeutic drug monitoring (TDM) is the recommended approach for attaining these goals. However, TDM is not universally available in all intensive care units (ICUs) and for all antimicrobial agents. In the absence of TDM, healthcare practitioners need to rely on several factors to make informed dosing decisions. These include the patient's clinical condition, causative pathogen, impact of organ dysfunction (requiring extracorporeal therapies), and physicochemical properties of the antimicrobials. In this context, the pharmacokinetics of antimicrobials vary considerably between different critically ill patients and within the same patient over the course of ICU stay. This variability underscores the need for individualized dosing. This review aimed to describe the main pathophysiological changes observed in critically ill patients and their impact on antimicrobial drug dosing decisions. It also aimed to provide essential practical recommendations that may aid clinicians in optimizing antimicrobial therapy among critically ill patients.

Improving Outcomes in Nosocomial Pneumonia: Recent Evidence and More Challenges

Nosocomial pneumonia (NP) represents a leading nosocomial infection and results in substantial morbidity and cost. Over the last several years, the evidence has evolved which directs our approach to NP. Specifically, the definition of NP and classification of its various subtypes has expanded to capture nuances among various phenotypes of this syndrome. For example, segregating those with hospital-acquired pneumonia (HAP) based on whether they subsequently require mechanical ventilation has been shown to be important. Likewise, newer data indicate the true economic cost of NP and underscore the diverse range of pathogens that can cause NP. Moreover, multidrug-resistant (MDR) bacteria have become a major threat in NP. Fortunately, newer simple preventive strategies have been tested and found to be effective at reducing the incidence of NP. Should prevention fail, a range of new antibiotics have been formally studied in NP and found to be effective. Some of these novel agents have relatively broad ranges of activity and are in vitro active against select MDR organisms. Others, however, are narrower in spectrum and directed against specific problem bacteria. In short, the literature in the field of NP has progressed rapidly, and clinicians require a clear appreciation of these changes so as to improve patient outcomes.

Year in Review 2023: Noteworthy Literature in Cardiothoracic Critical Care

This article reviews noteworthy investigations and society recommendations published in 2023 relevant to the care of critically ill cardiothoracic surgical patients. We reviewed 3,214 articles to identify 18 publications that add to the existing literature across a variety of topics including resuscitation, nutrition, antibiotic management, extracorporeal membrane oxygenation (ECMO), neurologic care following cardiac arrest, coagulopathy and transfusion, steroids in pulmonary infections, and updated guidelines in the management of acute respiratory distress syndrome (ARDS).

Is "Less be More" Still a Valid Concept in Intensive Care? A Review of Critical Care Randomized Clinical Trials from the New England Journal of Medicine

The concept of "Less is more" has been gaining increasing awareness and acceptance in Critical Care. In 2017, we attempted to systematically answer the question "Can less be more in intensive care" with empirical data. We reviewed all the critical care randomized clinical trials (RCTs) between 1 January 2008 and 5 October 2016 in the New England Journal of Medicine (NEJM). This article attempts to repeat the earlier exercise using data from 5 October 2016 to 31 December 2023. This analysis of critical care RCTs in the NEJM has shown three findings. Approximately three-quarter of RCTs in critical care in the NEJM between 2008 and 2023 failed to show benefit or harm. In the years 2008-2016, patients in the intervention cohort had a higher mortality compared to controls, but in the years 2016-2023, the difference in overall mortality in patients in the intervention and control arms was not statistically significant. Compared to the years 2008-2016, in the years from 2016 to 2023, the number of RCTs showing harm decreased and those showing benefit increased.

How to cite this article

Kapadia F, Bharadwaj S, Sharma R. Is "Less be More" Still a Valid Concept in Intensive Care? A Review of Critical Care Randomized Clinical Trials from the New England Journal of Medicine. Indian J Crit Care Med 2024;28(6):533-551.

Surveillance and prevention of healthcare-associated infections: best practices to prevent ventilator-associated events

INTRODUCTION

Ventilator associated pneumonia (VAP) leads to an increase in morbidity, mortality, and healthcare costs. In addition to increased evidence from the latest European and American guidelines (published in 2017 and 2022, respectively), in the last two years, several important clinical experiences have added new prevention tools to be included to improve the management of VAP.

AREAS COVERED

This paper is a narrative review of new evidence on VAP prevention. We divided VAP prevention measures into pharmacological, non-pharmacological, and ventilator care bundles.

EXPERT OPINION

Most of the effective strategies that have been shown to decrease the incidence of complications are easy to implement and inexpensive. The implementation of care bundles, accompanied by educational measures and a multidisciplinary team should be part of optimal management. In addition to ventilator care bundles for the prevention of VAP, it could possibly be beneficial to use ventilator care bundles for the prevention of noninfectious ventilator associated events.

Antibacterial agents active against Gram Negative Bacilli in phase I, II, or III clinical trials

INTRODUCTION

Antimicrobial resistance is a major threat to modern healthcare, and it is often regarded that the antibiotic pipeline is 'dry.'

AREAS COVERED

Antimicrobial agents active against Gram negative bacilli in Phase I, II, or III clinical trials were reviewed.

EXPERT OPINION

Nearly 50 antimicrobial agents (28 small molecules and 21 non-traditional antimicrobial agents) active against Gram-negative bacilli are currently in clinical trials. These have the potential to provide substantial improvements to the antimicrobial armamentarium, although it is known that 'leakage' from the pipeline occurs due to findings of toxicity during clinical trials. Significantly, a lack of funding for large phase III clinical trials is likely to prevent trials occurring for the indications most relevant to loss of life attributed to antimicrobial resistance such as ventilator-associated pneumonia. Non-traditional antimicrobial agents face issues in clinical development such as a lack of readily available and reliable susceptibility tests, and the potential need for superiority trials rather than non-inferiority trials. Most importantly, concrete plans must be made during clinical development for access of new antimicrobial agents to areas of the world where resistance to Gram negative bacilli is most frequent.

An in vitro study of the effects of respiratory circuit setup and parameters on aerosol delivery during mechanical ventilation

Introduction

Aerosol therapy is often prescribed concurrently during invasive mechanical ventilation (IMV). This study determines the effects of nebuliser position, circuit humidification source, and most importantly, lung health on the delivery of aerosol in simulated adult and paediatric IMV patients. Furthermore, the influence of closed suction catheters on aerosol delivery is also addressed.

Methods

A vibrating mesh nebuliser was used to deliver Albuterol to simulated adult and paediatric IMV patients with differing states of lung health. Four different nebuliser positions and two types of humidification were analysed. Closed suction catheter mounts, a mainstay in IMV therapy, were incorporated into the circuits. The mean ± SD dose of aerosol (%) was assayed from a filter at the distal end of the endotracheal tube.

Results

Nebuliser placement and circuit humidification source had no effect on the delivered dose (%) in adults, yet both significantly did in the simulated paediatric patients. The use of closed suction catheter mounts significantly reduced the delivered dose (%) in adults but not in paediatric patients. A simulated healthy lung state generated the largest delivered dose (%), irrespective of nebuliser position in the adult. However, different lung health and nebuliser positions yielded higher delivered doses (%) in paediatrics.

Conclusion

Lung health and respiratory circuit composition significantly affect aerosol delivery in both adult and paediatric IMV patients. Nebuliser placement and respiratory circuit humidification source do not affect the delivered dose in adult but do in paediatric IMV patients.

Long-term assessment of functional capacity, muscle function, lung function, and quality of life in survivors of ventilator-associated pneumonia

Background and objective

The many patients who develop ventilator-associated pneumonia (VAP) have generated numerous VAP survivors who are not followed up in the long term. This study aimed, primarily, to evaluate the long-term functional capacity, as measured using the Glittre-ADL test (TGlittre), of VAP survivors and, secondarily, to calculate the correlations of TGlittre with muscle and lung function.

Methods

This cross-sectional study evaluated 30 VAP survivors 10 months after discharge from the intensive care unit. The participants underwent the following assessments: TGlittre; respiratory muscle strength; handgrip strength (HGS); spirometry; Functional Assessment of Chronic Therapy (FACIT-F); and Short Form-36 (SF-36).

Results

The median TGlittre time was 95 (81-130)% of predicted, and 30 % of the participants performed poorly on TGlittre. One-third of the participants had abnormal spirometry results. TGlittre time was correlated with weight (rs = -0.412, P = 0.023), body index mass (BMI, rs = -0.400, P = 0.029), forced vital capacity (FVC, rs = -0.401, P = 0.030), HGS (rs = -0.571, P = 0.0009), FACIT-F score (rs = -0.405, P = 0.026), and different SF-36 domain scores. Participants who returned to work had a shorter TGlittre time than those who did not (89 (69-104) vs. 129 (102-183)% predicted). Multiple linear regression indicated that FVC and BMI explained 39 % of TGlittre variability.

Conclusion

VAP survivors had suboptimal functional capacity, low lung function, and general fatigue 10 months after discharge. The longer the TGlittre time was, the worse the lung function, muscle function, general fatigue, and quality of life were and the less likely the patient was to have returned to work.

Pathogenesis and therapeutic opportunities of gut microbiome dysbiosis in critical illness

For many years, it has been hypothesized that pathological changes to the gut microbiome in critical illness is a driver of infections, organ dysfunction, and other adverse outcomes in the intensive care unit (ICU). The advent of contemporary microbiome methodologies and multi-omics tools have allowed researchers to test this hypothesis by dissecting host-microbe interactions in the gut to better define its contribution to critical illness pathogenesis. Observational studies of patients in ICUs have revealed that gut microbial communities are profoundly altered in critical illness, characterized by markedly reduced alpha diversity, loss of commensal taxa, and expansion of potential pathogens. These key features of ICU gut dysbiosis have been associated with adverse outcomes including life-threatening hospital-acquired (nosocomial) infections. Current research strives to define cellular and molecular mechanisms connecting gut dysbiosis with infections and other outcomes, and to identify opportunities for therapeutic modulation of host-microbe interactions. This review synthesizes evidence from studies of critically ill patients that have informed our understanding of intestinal dysbiosis in the ICU, mechanisms linking dysbiosis to infections and other adverse outcomes, as well as clinical trials of microbiota-modifying therapies. Additionally, we discuss novel avenues for precision microbial therapeutics to combat nosocomial infections and other life-threatening complications of critical illness.

Inhaled drug delivery: a randomized study in intubated patients with healthy lungs

BACKGROUND

The administration technique for inhaled drug delivery during invasive ventilation remains debated. This study aimed to compare in vivo and in vitro the deposition of a radiolabeled aerosol generated through four configurations during invasive ventilation, including setups optimizing drug delivery.

METHODS

Thirty-one intubated postoperative neurosurgery patients with healthy lungs were randomly assigned to four configurations of aerosol delivery using a vibrating-mesh nebulizer and specific ventilator settings: (1) a specific circuit for aerosol therapy (SCAT) with the nebulizer placed at 30 cm of the wye, (2) a heated-humidified circuit switched off 30 min before the nebulization or (3) left on with the nebulizer at the inlet of the heated-humidifier, (4) a conventional circuit with the nebulizer placed between the heat and moisture exchanger filter and the endotracheal tube. Aerosol deposition was analyzed using planar scintigraphy.

RESULTS

A two to three times greater lung delivery was measured in the SCAT group, reaching 19.7% (14.0-24.5) of the nominal dose in comparison to the three other groups (p < 0.01). Around 50 to 60% of lung doses reached the outer region of both lungs in all groups. Drug doses in inner and outer lung regions were significantly increased in the SCAT group (p < 0.01), except for the outer right lung region in the fourth group due to preferential drug trickling from the endotracheal tube and the trachea to the right bronchi. Similar lung delivery was observed whether the heated humidifier was switched off or left on. Inhaled doses measured in vitro correlated with lung doses (R = 0.768, p < 0.001).

CONCLUSION

Optimizing the administration technique enables a significant increase in inhaled drug delivery to the lungs, including peripheral airways. Before adapting mechanical ventilation, studies are required to continue this optimization and to assess its impact on drug delivery and patient outcome in comparison to more usual settings.