Pneumonia part 1: Pathology, presentation and prevention

Development of a clinical prediction tool for extubation failure in pediatric cardiac intensive care unit

Introduction/objective

Extubation failure in pediatric patients with congenital or acquired heart diseases increases morbidity and mortality. This study aimed to develop a clinical risk score for predicting extubation failure to guide proper clinical decision-making and management.

Methods

We conducted a retrospective study. This clinical prediction score was developed using data from the Pediatric Cardiac Intensive Care Unit (PCICU) of the Faculty of Medicine, Chiang Mai University, Thailand, from July 2016 to May 2022. Extubation failure was defined as the requirement for re-intubation within 48 h after extubation. Multivariable logistic regression was used for modeling. The score was evaluated in terms of discrimination and calibration.

Results

A total of 352 extubation events from 270 patients were documented. Among these, 40 events (11.36%) were extubation failure. Factors associated with extubation failure included history of pneumonia (OR: 4.14, 95% CI: 1.83-9.37, p = 0.001), history of re-intubation (OR: 5.99, 95% CI: 2.12-16.98, p = 0.001), and high saturation in physiologic cyanosis (OR: 5.94, 95% CI: 1.87-18.84, p = 0.003). These three factors were utilized to develop the risk score. The score showed acceptable discrimination with an area under the curve (AUC) of 0.77 (95% CI: 0.69-0.86), and good calibration.

Conclusion

The derived Pediatric CMU Extubation Failure Prediction Score (Ped-CMU ExFPS) could satisfactorily predict extubation failure in pediatric cardiac patients. Employing this score could promote proper personalized care. We suggest conducting further external validation studies before considering implementation in practice.

Predictive factors of extubation failure in pediatric cardiac intensive care unit: A single-center retrospective study from Thailand

Introduction/objective

Extubation failure increases morbidity and mortality in pediatric cardiac patients, a unique population including those with congenital heart disease or acquired heart disease. This study aimed to evaluate the predictive factors of extubation failure in pediatric cardiac patients and to determine the association between extubation failure and clinical outcomes.

Methods

We conducted a retrospective study in the pediatric cardiac intensive care unit (PCICU) of the Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand, from July 2016 to June 2021. Extubation failure was defined as the re-insertion of the endotracheal tube within 48 hours after extubation. Multivariable log-binomial regression with generalized estimating equations (GEE) was performed to explore the predictive factors associated with extubation failure.

Results

We collected 318 extubation events from 246 patients. Of these, 35 (11%) events were extubation failures. In physiologic cyanosis, the extubation failure group had significantly higher SpO₂ than the extubation success group (P < 0.001). The predictive factors associated with extubation failure included a history of pneumonia before extubation (RR 3.09, 95% CI 1.54-6.23, P = 0.002), stridor after extubation (RR 2.57, 95% CI 1.44-4.56, P = 0.001), history of re-intubation (RR 2.24, 95% CI 1.21-4.12, P = 0.009), and palliative surgery (RR 1.87, 95% CI 1.02-3.43, P = 0.043).

Conclusion

Extubation failure was identified in 11% of extubation attempts in pediatric cardiac patients. The extubation failure was associated with a longer duration of PCICU stay but not with mortality. Patients with a history of pneumonia before extubation, history of re-intubation, post-operative palliative surgery, and post-extubation stridor should receive careful consideration before extubation and close monitoring afterward. Additionally, patients with physiologic cyanosis may require balanced circulation via regulated SpO₂.

Anti-inflammatory Effects of Mesenchymal Stem Cells and Their Secretomes in Pneumonia

Mesenchymal stem cells (MSCs) are multipotent progenitor cells that play crucial roles in the microenvironment of injured tissues. The potential therapeutics of MSCs have attracted extensive attention for several diseases such as acute respiratory distress syndrome (ARDS) and novel coronavirus disease 2019 (COVID-19) pneumonia. MSC-extracellular vesicles have been isolated from MSC-conditioned media (MSC-CM) with similar functional effects as parent MSCs. The therapeutic role of MSCs can be achieved through the balance between the inflammatory and regenerative microenvironments. Clinical settings of MSCs and their extracellular vesicles remain promising for many diseases, such as ARDS and pneumonia. However, their clinical applications remain limited due to the cost of growing and storage facilities of MSCs with a lack of standardized MSC-CM. This review highlights the proposed role of MSCs in pulmonary diseases and discusses the recent advances of MSC application for pneumonia and other lung disorders.

Esculetin Ameliorates Lipopolysaccharide-Induced Acute Lung Injury in Mice Via Modulation of the AKT/ERK/NF-κB and RORγt/IL-17 Pathways

Esculetin, a coumarin derivative from various natural plants, has an anti-inflammatory property. In the present study, we examined if esculetin has any salutary effects against lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. Acute lung injury (ALI) was induced via the intratracheal administration of LPS, and esculetin (20 and 40 mg/kg) was given intraperitoneally 30 min before LPS challenge. After 6 h of LPS administration, lung tissues were collected for analysis. Pretreatment with esculetin significantly attenuated histopathological changes, inflammatory cell infiltration, and production of pro-inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6, in the lung tissue. Furthermore, esculetin inhibited the protein kinase B (AKT), extracellular signal-regulated kinase (ERK), and nuclear factor-kappa B (NF-κB) pathways and downregulated the expression of RORγt and IL-17 in LPS-induced ALI. Our results indicated that esculetin possesses anti-inflammatory and protective effects against LPS-induced ALI via inhibition of the AKT/ERK/NF-κB and RORγt/IL-17 pathways.

Trends and health burden of hospitalized acute respiratory infections and impact of Haemophilus influenza immunization in a Tunisian university hospital: a twelve-year study

BACKGROUND

We aimed to describe the episodes and trends of admissions for community-acquired Respiratory Infections (RI) over a 12-year period and to assess the impact of Haemophilus influenza type b (Hib) vaccine on RI admissions in children aged up to 3 years.

METHODS

We conducted a twelve-year retrospective observational study on all community-acquired RI admitted to Fattouma Bourguiba Hospital in Monastir Governorate (Tunisia) from 1 January 2002 to 31 December 2013. RI cases were selected from the Regional Registry of Hospital Morbidity. Data were coded according to ICD-10. To assess the impact of the Hib vaccine, three cohorts were defined based on vaccine status (unvaccinated cohort, first vaccinated cohort (VC) by monovalent form and second VC by pentavalent combination).

RESULTS

Admissions for RI represented 17.6% (CI95%: 17.3-18.1) of all communicable diseases hospitalizations (n = 6 061/34 289). The crude incidence rates (CIR) per 100,000 inh were 24.2 for upper RI (URI) and 77.5 and for Lower RI (LRI) (p < 0.0001). Pneumonias represented 53.9% of LRI. Sex-ratio (male/female) was 1.12 for URI and 1.64 for LRI (p < 0.0001). At admission, the median age was 22 years (IQR: 3-52). Admission for Pneumonia increased significantly during study period (slope 'b' = 5.16; p < 0.0001) especially in children up to 5 years old (slope 'b' = 5.53) and in elderly (slope 'b' = 2.13). Among children up to 3 years old, the CIRs per 100,000 for Hib pneumonia admission were 11.6 in Non-Vaccinated Cohort (NVC), 10.6 in Vaccinated Cohort (VC) by protocol 1 (Hib Vaccine monovalent) and 0.80 in VC by protocol 2 (pentavalent vaccine combination).The relative risk reduction was 99% for protocol 2 (p < 0.001).

CONCLUSION

Admissions for RI in a  tertiary level hospital were common with an increasing trend. The Hib immunization program, in particular the pentavalent combination, has had a positive impact on the reduction of related acute diseases.

Ginsenoside Rb1 ameliorates Staphylococcus aureus-induced Acute Lung Injury through attenuating NF-κB and MAPK activation

Acute lung injury (ALI) is clinically characterized by excessive inflammation leading to acute respiratory distress syndrome (ARDS), having high morbidity and mortality both in human and animals. Ginsenoside Rb1 (Rb1) is a major primary bioactive component extracted by Panax ginseng, which has numerous pharmacological functions such as anti-cancer, anti-inflammatory, and antioxidant. However, the anti-inflammatory effects of Rb1 in Staphylococcus aureus (S. aureus)-induced ALI in mice have not been investigated. The aim of the current study was to determine the anti-inflammatory influence of Rb1 on S. aureus-induced ALI in mice, and to explore its possible underlying principle mechanisms in RAW 264.7 macrophage cells. The results of physical morphology, histopathological variation and wet-to-dry weight ratio of lungs revealed that Rb1 significantly attenuated S. aureus-induced lung injury. Furthermore, qPCR results displayed that Rb1 inhibited IL-1β, IL-6 and TNF-α production both in vivo and in vitro. The activation of Toll-like receptor 2 (TLR2) by S. aureus was inhibited by application of Rb1 as confirmed by results of immunofluorescence assay. The expression of NF-kB and MAPK signaling proteins revealed that Rb1 significantly attenuated the phosphorylation of p65, ERK, as well as JNK. Altogether, the results of this experiment presented that Rb1 has ability to protect S. aureus-induced ALI in mice by attenuating TLR-2-mediated NF-kB and MAPK signaling pathways. Consequently, Rb-1 might be a potential medicine in the treatment of S. aureus-induced lung inflammation.

Magnoflorine Ameliorates Lipopolysaccharide-Induced Acute Lung Injury via Suppressing NF-κB and MAPK Activation

Acute lung injury (ALI) which is featured by a strong pulmonary inflammation, is a major cause of morbidity and mortality in critically ill patients. Magnoflorine, a quaternary alkaloid isolated from Chinese herb Magnolia or Aristolochia, has been reported to have potent anti-inflammatory properties. However, the effect of magnoflorine on lipopolysaccharide (LPS)-induced ALI in mice has not been reported. The purpose of the present study is to investigate the anti-inflammatory effect of magnoflorine on LPS-induced ALI and elucidate its possible molecular mechanisms in RAW264.7 cells. The results of histopathological changes as well as the myeloperoxidase (MPO) activity indicated that magnoflorine significantly alleviated the lung injury induced by LPS. In addition, qPCR results showed that magnoflorine dose-dependently decreased the expression of pro-inflammatory cytokines TNF-α, IL-1β, and IL-6. Immunofluorescence assay also confirmed that the level of Toll-like receptor 4 (TLR4) induced by LPS was inhibited by magnoflorine treatment. Further experiments were performed using Western blotting to detect the expression of related proteins in the NF-κB and MAPK signaling pathways. The results showed that magnoflorine suppressed the levels of phosphorylated p65, IκBα, p38, ERK, and JNK. In conclusion, all data indicate that magnoflorine could protect against LPS-induced inflammation in ALI at least partially by inhibiting TLR4-mediated NF-κB and MAPK signaling pathways.

The Metabolic Sensor GPR43 Receptor Plays a Role in the Control of Klebsiella pneumoniae Infection in the Lung

Pneumonia is one of the leading causes of death and mortality worldwide. The inflammatory responses that follow respiratory infections are protective leading to pathogen clearance but can also be deleterious if unregulated. The microbiota is known to be an important protective barrier against infections, mediating both direct inhibitory effects against the potential pathogen and also regulating the immune responses contributing to a proper clearance of the pathogen and return to homeostasis. GPR43 is one receptor for acetate, a microbiota metabolite shown to induce and to regulate important immune functions. Here, we addressed the role of GPR43 signaling during pulmonary bacterial infections. We have shown for the first time that the absence of GPR43 leads to increased susceptibility to Klebsiella pneumoniae infection, which was associated to both uncontrolled proliferation of bacteria and to increased inflammatory response. Mechanistically, we showed that GPR43 expression especially in neutrophils and alveolar macrophages is important for bacterial phagocytosis and killing. In addition, treatment with the GPR43 ligand, acetate, is protective during bacterial lung infection. This was associated to reduction in the number of bacteria in the airways and to the control of the inflammatory responses. Altogether, GPR43 plays an important role in the “gut–lung axis” as a sensor of the host gut microbiota activity through acetate binding promoting a proper immune response in the lungs.

Inhibition of Phosphodiesterase-4 during Pneumococcal Pneumonia Reduces Inflammation and Lung Injury in Mice

Pneumococcal pneumonia is a leading cause of mortality worldwide. The inflammatory response to bacteria is necessary to control infection, but it may also contribute to tissue damage. Phosphodiesterase-4 inhibitors, such as rolipram (ROL), effectively reduce inflammation. Here, we examined the impact of ROL in a pneumococcal pneumonia murine model. Mice were infected intranasally with 10(5)-10(6) CFU of Streptococcus pneumoniae, treated with ROL in a prophylactic or therapeutic schedule in combination, or not, with the antibiotic ceftriaxone. Inflammation and bacteria counts were assessed, and ex vivo phagocytosis assays were performed. ROL treatment during S. pneumoniae infection decreased neutrophil recruitment into lungs and airways and reduced lung injury. Prophylactic ROL treatment also decreased cytokine levels in the airways. Although modulation of inflammation by ROL ameliorated pneumonia, bacteria burden was not reduced. On the other hand, antibiotic therapy reduced bacteria without reducing neutrophil infiltration, cytokine level, or lung injury. Combined ROL and ceftriaxone treatment decreased lethality rates and was more efficient in reducing inflammation, by increasing proresolving protein annexin A1 (AnxA1) expression, and bacterial burden by enhancing phagocytosis. Lack of AnxA1 increased inflammation and lethality induced by pneumococcal infection. These data show that immunomodulatory effects of phosphodiesterase-4 inhibitors are useful during severe pneumococcal pneumonia and suggest their potential benefit as adjunctive therapy during infectious diseases.

General practitioners' contribution to the management of community-acquired pneumonia in the Netherlands: a retrospective analysis of primary care, hospital, and national mortality databases with individual data linkage

BACKGROUND

Community-acquired pneumonia (CAP) is an important cause of hospital admission and death, but the extent of the problem of CAP at the primary healthcare level is largely unknown.

AIMS

To investigate the contribution of general practitioners (GPs) to the management of patients with CAP in the Netherlands.

METHODS

The study population consisted of all people enlisted in a GP network. We obtained information on CAP episodes from GP electronic records (using ICPC code R81) during the years 2002-2009. CAP registrations were also obtained from national hospital discharge data (ICD-9 codes) and cause of death statistics (ICD-10 codes). The three registration systems were linked at the individual level. We used descriptive analyses to estimate the annual number of CAP episodes (i.e. defined as a CAP diagnosis within 30 days).

RESULTS

From 2002 to 2009 the mean annual size of the study population was 395,039. For this population, 3,700 (0.9%) CAP episodes per year were registered in at least one of the registration systems, 2,933 (79%) of which were in the GP system only. Recovery within 30 days occurred on average in 95% (2,791/2,933) of the CAP episodes annually registered by a GP, while 2.3% (67/2,933) of patients with a GP-registered CAP episode were admitted to hospital within 30 days and 1% (26/2,933) had a fatal outcome within 30 days.

CONCLUSIONS

The vast majority of CAP episodes registered in the Netherlands are managed successfully at the GP level without hospitalisation.