Universal paediatric videolaryngoscopy and glottic view grading: a prospective observational study.

BACKGROUND: Although videolaryngoscopy has been proposed as a default technique for tracheal intubation in children, published evidence on universal videolaryngoscopy implementation programmes is scarce. We aimed to determine if universal, first-choice videolaryngoscopy reduces the incidence of restricted glottic views and to determine the diagnostic performance of the Cormack and Lehane classification to discriminate between easy and difficult videolaryngoscopic tracheal intubations in children. METHODS: We conducted a prospective observational study within a structured universal videolaryngoscopy implementation programme. We used C-MAC™ (Karl Storz, Tuttlingen, Germany) videolaryngoscopes in all anaesthetised children undergoing elective tracheal intubation for surgical procedures. The direct and videolaryngoscopic glottic views were classified using a six-stage grading system. RESULTS: There were 904 tracheal intubations in 809 children over a 16-month period. First attempt and overall success occurred in 607 (67%) and 903 (> 99%) tracheal intubations, respectively. Difficult videolaryngoscopic tracheal intubation occurred in 47 (5%) and airway-related adverse events in 42 (5%) tracheal intubations. Direct glottic view during laryngoscopy was restricted in 117 (13%) and the videolaryngoscopic view in 32 (4%) tracheal intubations (p < 0.001). Videolaryngoscopy improved the glottic view in 57/69 (83%) tracheal intubations where the vocal cords were only just visible, and in 44/48 (92%) where the vocal cords were not visible by direct view. The Cormack and Lehane classification discriminated poorly between easy and difficult videolaryngoscopic tracheal intubations with a mean area under the receiver operating characteristic curve of 0.68 (95%CI 0.59-0.78) for the videolaryngoscopic view compared with 0.80 (95%CI 0.73-0.87) for the direct glottic view during laryngoscopy (p = 0.005). CONCLUSIONS: Universal, first-choice videolaryngoscopy reduced substantially the incidence of restricted glottic views. The Cormack and Lehane classification was not a useful tool for grading videolaryngoscopic tracheal intubation in children.

Conquering the obstacles during the intervention of a proximal chronic total occlusion of right coronary artery with a concurrent significant ostial stenosis: a case report.

Percutaneous coronary intervention (PCI) on a proximal chronic total occlusion (CTO) of the right coronary artery (RCA) with concurrent ostial stenosis can be challenging because of the significant difficulty in properly engaging the catheter and providing stable support during the procedure. We report the case of a 57-year-old man with chronic coronary syndrome who underwent an elective PCI at the Dr. Soetomo General Hospital in Surabaya, on April 13th, 2022. At the beginning of the procedure, there was difficulty in intubating the RCA, which required the guide catheter replacement. The angiography revealed a significant lesion at the ostium, a CTO at proximal to mid- RCA with bridging collaterals, and a significant distal lesion. Several strategies to improve guiding catheter support during PCI are using large and supportive shape guide catheters, deep guide catheter intubation, extra support wire, microcatheter and guide catheter extension. The risk of pressure dampening and ischaemia upon engagement should always be kept under consideration.

Toxicity and biokinetics following pulmonary exposure to aluminium (aluminum): A review.

During the manufacture and use of aluminium (aluminum), inhalation exposure may occur. We reviewed the pulmonary toxicity of this metal including its toxicokinetics. The normal serum/plasma level based on 17 studies was 5.7 ± 7.7 µg Al/L (mean ± SD). The normal urine level based on 15 studies was 7.7 ± 5.3 µg/L. Bodily fluid and tissue levels during occupational exposure are also provided, and the urine level was increased in aluminium welders (43 ± 33 µg/L) based on 7 studies. Some studies demonstrated that aluminium from occupational exposure can remain in the body for years. Excretion pathways include urine and faeces. Toxicity studies were mostly on aluminium flakes, aluminium oxide and aluminium chlorohydrate as well as on mixed exposure, e.g. in aluminium smelters. Endpoints affected by pulmonary aluminium exposure include body weight, lung function, lung fibrosis, pulmonary inflammation and neurotoxicity. In men exposed to aluminium oxide particles (3.2 µm) for two hours, lowest observed adverse effect concentration (LOAEC) was 4 mg Al2O3/m3 (= 2.1 mg Al/m3), based on increased neutrophils in sputum. With the note that a similar but not statistically significant increase was seen during control exposure. In animal studies LOAECs start at 0.3 mg Al/m3. In intratracheal instillation studies, all done with aluminium oxide and mainly nanomaterials, lowest observed adverse effect levels (LOAELs) started at 1.3 mg Al/kg body weight (bw) (except one study with a LOAEL of ∼0.1 mg Al/kg bw). The collected data provide information regarding hazard identification and characterisation of pulmonary exposure to aluminium.

Safety of propofol-assisted deep extubation in the dental treatment of children-a retrospective, observational study.

PURPOSE: Awake extubation and deep extubation are commonly used anesthesia techniques. In this study, the safety of propofol-assisted deep extubation in the dental treatment of children was assessed. MATERIALS AND METHODS: Children with severe caries who received dental treatment under general anesthesia and deep extubation between January 2017 and June 2023 were included in this study. Data were collected on the following variables: details and time of anesthesia, perioperative vital signs, and incidence of postoperative complications. The incidence of laryngeal spasm (LS) was considered to be the primary observation indicator. RESULTS: The perioperative data obtained from 195 children undergoing dental treatment was reviewed. The median age was 4.2 years (range: 2.3 to 9.6 years), and the average duration of anesthesia was 2.56 h (range 1 to 4.5 h). During intubation with a videoscope, purulent mucus was found in the pharyngeal cavity of seven children (3.6%); LS occurred in five of them (2.6%), and one child developed a fever (T = 37.8 °C) after discharge. Five children (2.6%) experienced emergence agitation (EA) in the recovery room. Also, 13 children (6.7%) experienced epistaxis; 10 had a mild experience and three had a moderate experience. No cases of airway obstruction (AO) and hypoxemia were recorded. The time to open eyes (TOE) was 16.3 ± 7.2 min. The incidence rate of complications was 23/195 (11.8%). Emergency tracheal reintubation was not required. Patients with mild upper respiratory tract infections showed a significantly higher incidence of complications (P < 0.001). CONCLUSIONS: Propofol-assisted deep extubation is a suitable technique that can be used for pediatric patients who exhibited non-cooperation in the outpatient setting. Epistaxis represents the most frequently encountered complication. Preoperative upper respiratory tract infection significantly increases the risk of complications. The occurrence of EA was notably lower than reported in other studies.

Basing intubation of acutely hypoxemic patients on physiologic principles.

The decision to intubate a patient with acute hypoxemic respiratory failure who is not in apparent respiratory distress is one of the most difficult clinical decisions faced by intensivists. A conservative approach exposes patients to the dangers of hypoxemia, while a liberal approach exposes them to the dangers of inserting an endotracheal tube and invasive mechanical ventilation. To assist intensivists in this decision, investigators have used various thresholds of peripheral or arterial oxygen saturation, partial pressure of oxygen, partial pressure of oxygen-to-fraction of inspired oxygen ratio, and arterial oxygen content. In this review we will discuss how each of these oxygenation indices provides inaccurate information about the volume of oxygen transported in the arterial blood (convective oxygen delivery) or the pressure gradient driving oxygen from the capillaries to the cells (diffusive oxygen delivery). The decision to intubate hypoxemic patients is further complicated by our nescience of the critical point below which global and cerebral oxygen supply become delivery-dependent in the individual patient. Accordingly, intubation requires a nuanced understanding of oxygenation indexes. In this review, we will also discuss our approach to intubation based on clinical observations and physiologic principles. Specifically, we consider intubation when hypoxemic patients, who are neither in apparent respiratory distress nor in shock, become cognitively impaired suggesting emergent cerebral hypoxia. When deciding to intubate, we also consider additional factors including estimates of cardiac function, peripheral perfusion, arterial oxygen content and its determinants. It is not possible, however, to pick an oxygenation breakpoint below which the benefits of mechanical ventilation decidedly outweigh its hazards. It is futile to imagine that decision making about instituting mechanical ventilation in an individual patient can be condensed into an algorithm with absolute numbers at each nodal point. In sum, an algorithm cannot replace the presence of a physician well skilled in the art of clinical evaluation who has a deep understanding of pathophysiologic principles.

Comparing the posture and comfort of anaesthesiologists during laryngoscopy and tracheal intubation in the head-elevated laryngoscopy position in supine position and with a 25° backup: A randomised clinical crossover trial.

Background and Aims: The head-elevated laryngoscopy position (HELP) and a 25° backup have been proposed to enhance glottic visualisation, yet concerns about ergonomic discomfort hinder their widespread adoption. This study compares the comfort and posture adopted by anaesthesiologists while performing laryngoscopy and tracheal intubation with patients in HELP while in a supine position or with 25° backup. Methods: The study included 48 patients aged 18-60 years with normal airways and 12 experienced anaesthesiologists. Patients were randomised into two groups using permuted block randomisation. Anaesthesiologists performed laryngoscopy and intubation in supine HELP and 25° backup HELP positions. Anaesthesiologist's posture was determined by measuring the angles of neck, wrist, elbow, back and knee joints, which were compared using Student's t-test, and subjective comfort assessed on a Likert scale was compared using the Chi-square test. As mentioned by the anaesthesiologist, Cormack- Lehane grading was also noted and compared using a Chi-square test between groups, taking a P value <0.05 as significant. Results: Both positions demonstrated comparable anaesthesiologist posture (P = 0.919) and comfort (P = 0.644). However, the 25° backup HELP positions significantly improved Cormack-Lehane grades, with 68% achieving grade 1 compared to 31% in the supine HELP group (P = 0.012). Haemodynamic stability and tracheal intubation time showed no significant differences between the groups (P = 0.475 and 0.117, respectively), and no complications were reported in either group. Conclusion: Anaesthesiologists' posture and comfort during laryngoscopy and tracheal intubation are similar between supine and 25° backup in patients with easy airways.

Development of an evidence-based nursing practice program for preventing unplanned endotracheal extubations in the intensive care unit: A Delphi method study.

AIMS: This study aims to develop an evidence-based nursing practice program to prevent unplanned endotracheal extubation (UEE) among adult patients in the intensive care unit (ICU). DESIGN: This study uses the Delphi method to develop an evidence-based nursing practice program. METHODS: A comprehensive review of 18 databases and evidence-based websites was conducted to gather, assess and synthesize evidence on preventing UEEs in adult patients. Using this synthesized evidence, a questionnaire was formulated for further investigation. Subsequently, input was solicited from experts through Delphi surveys to establish an evidence-based nursing practice protocol for preventing UEEs in adult ICU patients. Consistency in consultation results guided subsequent rounds of consultation. RESULTS: The developed program comprised 43 evidence items categorized into nine dimensions, including risk assessment for unplanned extubation, sedation, analgesia, delirium, balloon management, psychosocial care, early extubation, catheter immobilization and protective restraints. Two rounds of expert inquiry yielded recovery rates of 94.7% and 100% for the first and second questionnaires, respectively. Kendall W values ranged from .224 to .353 (p < .001). CONCLUSION: This study developed an evidence-based nursing practice program to prevent UEE in adult ICU patients, employing evidence-based practices and Delphi expert consultation methods. However, further validation of the program's effectiveness is warranted. REPORTING METHOD: Findings were reported according to the Standards for Reporting Qualitative Research checklist. PATIENT OR PUBLIC CONTRIBUTION: Nurses contributed to the study by participating in investigations. IMPLICATIONS FOR THE PROFESSION AND PATIENT CARE: The program developed in this study offers an evidence-based framework for preventing unplanned extubation in hospitals, thereby reducing its incidence and enhancing the quality of nursing care.

Mice fatal pneumonia model induced by less-virulent Streptococcus pneumoniae via intratracheal aerosolization.

Aim: Animal models of fatal pneumonia caused by Streptococcus pneumoniae (Spn) have not been reliably generated using many strains of less virulent serotypes. Materials & methods: Pulmonary infection of a less virulent Spn serotype1 strain in the immunocompetent mice was established via the intratracheal aerosolization (ITA) route. The survival, local and systemic bacterial spread, pathological changes and inflammatory responses of this model were compared with those of mice challenged via the intratracheal instillation, intranasal instillation and intraperitoneal injection routes. Results: ITA and intratracheal instillation both induced fatal pneumonia; however, ITA resulted in better lung bacterial deposition and distribution, pathological homogeneity and delivery efficiency. Conclusion: ITA is an optimal route for developing animal models of severe pulmonary infections.

What is this article about? Streptococcus pneumoniae (Spn), a type of bacteria, can cause serious illness and death in otherwise healthy people. One way that we study pneumonia is using animals. However, pneumonia in animals infected with Spn in the laboratory does not mimic that in humans very well. To study this illness, we need a new way to set up a proper animal model.What were the results? This study set up a method called intratracheal aerosolization (ITA). In ITA, bacteria can form small droplets called aerosols and reach the deepest parts of a mouse's lung. ITA can cause deadly illness in mice infected with Spn, even if the mice are healthy.What do the results of the study mean? The ITA method could be a useful tool to set up animal models of serious pneumonia with less virulent bacteria.

Comparative Effects of Umbilical Cord Mesenchymal Stem Cell Treatment via Different Routes on Lipopolysaccharide-Induced Acute Lung Injury.

BACKGROUND: Although umbilical cord mesenchymal stem cell (UCMSC) infusion has been proposed as a promising strategy for the treatment of acute lung injury (ALI), the parameters of UCMSC transplantation, such as infusion routes and doses, need to be further optimized. METHODS: In this study, we compared the therapeutic effects of UCMSCs transplanted via intravenous injection and intratracheal instillation on lipopolysaccharide-induced ALI using a rat model. Following transplantation, levels of inflammatory factors in serum; neutrophils, total white blood cells, and lymphocytes in bronchoalveolar lavage fluid (BALF); and lung damage levels were analyzed. RESULTS: The results indicated that UCMSCs administered via both intravenous and intratracheal routes were effective in alleviating ALI, as determined by analyses of arterial blood gas, lung histopathology, BALF contents, and levels of inflammatory factors. Comparatively, the intratracheal instillation of UCMSCs was found to result in lower levels of lymphocytes and total proteins in BALF, whereas greater reductions in the serum levels of tumor necrosis factor α (TNF-α) and interleukin 1ß (IL-1ß) were detected in rats receiving intravenously injected stem cells. CONCLUSIONS: Our findings in this study provide convincing evidence to indicate the efficacy of UCMSC therapy in the treatment of ALI mediated via different delivery routes, thereby providing a reliable theoretical basis for further clinical studies. Moreover, these findings imply that the effects obtained using the two assessed delivery routes for UCMSC transplantation are mediated via different mechanisms, which could be attributable to different cellular or molecular targets.

Intratracheal instillation of budesonide suspension versus normal saline on oxidative stress in neonates with meconium aspiration syndrome.

BACKGROUND: Presently, the efficacy of neonatal resuscitation techniques via interventions such as oral, nasal, and endotracheal suction for preventing meconium aspiration syndrome (MAS) after delivery has not been satisfactory. OBJECTIVE: This study aimed to investigate the role of intratracheal instillation of budesonide on oxidative stress in MAS. METHODS: Sixty-two neonates with MAS admitted to Huai'an Maternity and Child Healthcare Hospital from January 2018 to June 2020 were divided into a study group (intratracheal instillation of 2 ml budesonide suspension; n = 31) and a control group (intratracheal instillation of 2 ml normal saline; n = 31). Collect data from two groups of patients and evaluate clinical outcomes, including oxygenation index (OI), as well as serum total oxidant status (TOS), total antioxidant capacity (TAC), oxidative stress index (OSI) and 8-Isoprostane before treatment and 72h after admission. RESULTS: We found no statistical differences in mortality, complication rate, total oxygen inhalation time, OI before treatment and 72h after admission between the two groups of neonates with MAS, while the duration of invasive respiratory support in the study group was significantly shorter than in the control group. Also, serum TAC, TOS, OSI and 8-isoprostane levels were not statistically different before treatment between the two groups. After 72h of admission, OSI and 8-Isoprostane in neonates with MAS in the study group were much lower than those in the control group. TOS, OSI, 8-Isoprostane in the control group and 8-Isoprostane in the study group were significantly higher than those before treatment. As for TAC and TOS, no significant differences were observed between the two groups. CONCLUSION: Intratracheal instillation of budesonide was shown to alleviate oxidative stress and shorten invasive ventilation time in neonates with MAS.

Hyperangulated vs. Macintosh videolaryngoscopy in adults with anticipated difficult airway management: a randomised controlled trial.

BACKGROUND: It is not certain whether the blade geometry of videolaryngoscopes, either a hyperangulated or Macintosh shape, affects glottic view, success rate and/or tracheal intubation time in patients with expected difficult airways. We hypothesised that using a hyperangulated videolaryngoscope blade would visualise a higher percentage of glottic opening compared with a Macintosh videolaryngoscope blade in patients with expected difficult airways. METHODS: We conducted an open-label, patient-blinded, randomised controlled trial in adult patients scheduled to undergo elective ear, nose and throat or oral and maxillofacial surgery, who were anticipated to have a difficult airway. All airway operators were consultant anaesthetists. Patients were allocated randomly to tracheal intubation with either hyperangulated (C-MAC D-BLADE™) or Macintosh videolaryngoscope blades (C-MAC™). The primary outcome was the percentage of glottic opening. First attempt success was designated a key secondary outcome. RESULTS: We assessed 2540 adults scheduled for elective head and neck surgery for eligibility and included 182 patients with expected difficult airways undergoing orotracheal intubation. The percentage of glottic opening visualised, expressed as median (IQR [range]), was 89 (69-99 [0-100])% with hyperangulated videolaryngoscope blades and 54 (9-90 [0-100])% with Macintosh videolaryngoscope blades (p < 0.001). First-line hyperangulated videolaryngoscopy failed in one patient and Macintosh videolaryngoscopy in 12 patients (13%, p = 0.002). First attempt success rate was 97% with hyperangulated videolaryngoscope blades and 67% with Macintosh videolaryngoscope blades (p < 0.001). CONCLUSIONS: Glottic view and first attempt success rate were superior with hyperangulated videolaryngoscope blades compared with Macintosh videolaryngoscope blades when used by experienced anaesthetists in patients with difficult airways.

Remimazolam sedation for awake tracheal intubation.

We present a case of a 55-year-old woman presenting for an elective minor procedure. Following a previous anaesthetic, a 'can't intubate, can't oxygenate' incident had been documented. She had since undergone awake tracheal intubation for procedures requiring general anaesthesia. We were able to safely facilitate awake tracheal intubation using remimazolam for sedation. Remimazolam is a novel ultra-short acting benzodiazepine with similar pharmacodynamic effects to its parent compound midazolam, having minimal cardiovascular or respiratory effects and offering excellent anxiolysis and amnesia. It has a significantly shorter duration of action than midazolam, making it a valuable sedative agent for awake tracheal intubation. The patient remained stable throughout the procedure, with minimal effects on the respiratory and cardiovascular systems. The quality of sedation was reported as highly satisfactory by both the patient and the team.

Efficacy and safety of video double-lumen tube intubation in lateral position in patients undergoing thoracic surgery: a randomized controlled trial.

BACKGROUND: Video double-lumen tube (VDLT) intubation in lateral position is a potential alternative to intubation in supine position in patients undergoing thoracic surgery. This non-inferiority trial assessed the efficacy and safety of VDLT intubation in lateral position. METHODS: Patients (18-70 yr) undergoing right thoracoscopic lung surgery were randomized to either the left lateral position group (group L) or the supine position group (group S). The VDLT was placed under video larygoscopy. The primary endpoint was the intubation time. Secondary endpoints included VDLT displacement rate, intubation failure rate, the satisfaction of surgeon and nurse, and intubation-related adverse events. RESULTS: The analysis covered 80 patients. The total intubation time was 52.0 [20.4]s in group L and 34.3 [13.2]s in group S, with a mean difference of 17.6 s [95% confidence interval (CI): 9.9 s to 25.3 s; P = 0.050], failing to demonstrate non-inferiority with a non-inferiority margin of 10 s. Group L, compared with group S, had significantly lower VDLT displacement rate (P = 0.017) and higher nurse satisfaction (P = 0.026). No intubation failure occurred in any group. Intubation complications (P = 0.802) and surgeon satisfaction (P = 0.415) were comparable between two groups. CONCLUSIONS: The lateral VDLT intubation took longer time than in the supine position, and non-inferiority was not achieved. The incidence of displacement as the secondary endpoint was lower in the L group, possibly due to changing body positions beforehand. The indication of lateral VDLT intubation should be based on a balance between the safety of airway management and the lower incidence of displacement. TRIAL REGISTRATION: The study was registered at Chictr.org.cn with the number ChiCTR2200064831 on 19/10/2022.

Models for Inducing Experimental Cryptococcosis in Mice.

Cryptococcus neoformans and Cryptococcus gattii are the predominant etiological agents of cryptococcosis, a particularly problematic disease in immunocompromised individuals. The increased clinical use of immunosuppressive drugs, the inherent ability of Cryptococcus species to suppress and evade host immune responses, and the emergence of drug-resistant yeast support the need for model systems that facilitate the design of novel immunotherapies and antifungals to combat disease progression. The mouse model of cryptococcosis is a widely used system to study Cryptococcus pathogenesis and the efficacy of antifungal drugs in vivo. In this chapter, we describe three commonly used strategies to establish cryptococcosis in mice: intranasal, intratracheal, and intravenous inoculations. Also, we discuss the methodology for delivering drugs to mice via intraperitoneal injection.

Radioiodine Therapy: Alternative for the Treatment of Complicated Thyroid Ectopia.

Thyroid ectopy is the presence of thyroid tissue outside its normal cervical location. Clinical manifestations of thyroid ectopy are varied. The latter complications can be life-threatening. Emergency treatment is often surgical or endoscopic. We report a case of a 26-year-old man with tracheal thyroid ectopy, complicated by respiratory distress, in whom conventional treatments were not feasible. The patient was treated with radioiodine-131 administered in liquid form. The final control showed the complete resolution of the intra-tracheal mass. Intra-tracheal thyroid ectopy is a rare anomaly in which surgery is the traditional treatment. In certain cases where surgery is not feasible or refused, treatment with iodine-131 is a safe and effective alternative for the removal of ectopic thyroid tissue. The aim of our work is to show the significant efficiency of radioiodine therapy as an alternative for the treatment of complicated thyroid ectopia.

Efficacy of intratracheal dexmedetomidine on recovery from general anaesthesia in paediatric patients undergoing lower abdominal surgeries: A randomised controlled trial.

BACKGROUND: This study investigated the effectiveness of intratracheal dexmedetomidine in reducing untoward laryngeal responses in paediatrics undergoing lower abdominal surgeries. METHODS: This trial included 60 patients divided into two groups scheduled for lower abdominal surgeries. Group D were given intratracheal dexmedetomidine at a dosage of 0.5mg/kg, while Group C received intratracheal saline (0.9%). The cough severity score, the Paediatric Objective Pain Scale for pain assessment, awareness, extubation, emergence agitation score, Ramsay sedation score and adverse effects were recorded. RESULTS: There was a significant difference in the incidence of coughing severity between Groups D and C both at extubation and after five minutes of extubation (p < 0.001). The median scores of the Paediatric Objective Pain Scales and the median agitation scales of Group D were significantly lower over the first four hours (p < 0.050). The mean time to first request rescue analgesia was significantly longer in the D group than in the control group (p < 0.001). The mean total consumption of rescue analgesia in the first 24 hours postoperatively was significantly lower in the dexmedetomidine group (p < 0.050). Awareness and extubation times were comparable in both groups, and none of the subjects reported any adverse effects. CONCLUSION: In the current study, lower abdominal surgery patients who received intratracheal dexmedetomidine at a dose of 0.5mg/kg 30 minutes before the completion of the procedure experienced smooth extubation and balanced anaesthetic recovery.

Cellular Distribution and Intracellular Localization of Different Sizes of Fluorescent Thiol-Organosilica Particles in Mouse Lungs.

We investigated the distribution of intratracheally administered thiol-organosilica (thiol-OS) particles in mouse lungs. Toward this end, single doses of thiol-OS particles containing fluorescein (140 nm in diameter) (F140) and rhodamine B (Rh) (Rh160, Rh280, Rh420, Rh640, and Rh1630 with diameters of 160, 280, 420, 640, and 1630 nm, respectively) were administered. After 24 h, fluorescence imaging revealed homogeneous fluorescence with a patchier pattern on the lung surface and no difference among the six particle sizes. Simultaneous dual administration of Rh and F140 particles did not reveal any size-dependent differences in the lung surface fluorescence. Fluorescence microscopy of the lung sections revealed a similar tissue distribution in the fluorescent areas of Rhs and F140. Some fluorescent areas showed one type of particle fluorescence or only one fluorescence. Cellular distribution of particles was observed in bronchoalveolar lavage cells and lung sections under a high magnification, and correlative light and electron microscopy revealed large cells with fluorescence corresponding to both particle types and small cells with fluorescence of individual particle types, indicating a cell-subset-dependent particle size effect. Rh280, Rh420, and Rh640 exhibited significant size effects and were taken up by alveolar macrophages. Extracellular particles were observed, indicating that saturation exceeded the particle dose threshold in the alveoli. F140 taken up by small and large macrophages colocalized with CD68, CD11c, and CD11b and correlated with CD11c. The size effect, intracellular localization, and extracellular distribution of particles provide insights into lung and systemic drug delivery.