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Background Patients with acute respiratory failure, impaired consciousness, and impaired airway reflexes will require invasive mechanical ventilation. Monitoring of such patients is important. The use of ventilator scalars and loops help in monitoring, diagnosing the abnormality, and treating the patients effectively. We report a rare cause one should suspect in a case of persistent and fixed air leak in a patient requiring mechanical ventilation. Case presentation We describe a 28-year-old young patient requiring ventilator support due to neuromuscular weakness. His neuromuscular weakness was rapidly progressing involving the respiratory muscles. The patient was intubated and put on mechanical ventilator support. He was transferred from another health care center to our hospital. On evaluation, the patient was intubated with ETT no 8. The patient had persistent air leak as observed on the ventilator graphics. We checked for ETT cuff malfunction, ventilator circuit, catheter mount, and HME for any disconnection causing the leak. The air leak which we observed in our patient was due to the malpositioned Ryle’s tube. Conclusions Vigilant monitoring of patients requiring mechanical ventilation is necessary. For the evaluation of the cause of air leak, algorithmic approach will help in correctly identifying the abnormality.

Purpose The COVID-19 pandemic threatens our current ICU capabilities nationwide. As the number of COVID-19 positive patients across the nation continues to increase, the need for options to address ventilator shortages is inevitable. Multi-patient ventilation (MPV), in which more than one patient can use a single ventilator base unit, has been proposed as a potential solution to this problem. To our knowledge, this option has been discussed but remains untested in live patients with differing severity of lung pathology. Methods The objective of this study was to address ventilator shortages and patient stacking limitations by developing and validating a modified breathing circuit for two patients with differing lung compliances using simple, off-the-shelf components. A multi-patient ventilator circuit (MPVC) was simulated with a mathematical model and validated with four animal studies. Each animal study had two human-sized pigs: one healthy and one with lipopolysaccharide (LPS) induced ARDS. LPS was chosen because it lowers lung compliance similar to COVID-19. In a previous study, a control group of four pigs was given ARDS and placed on a single patient ventilation circuit (SPVC). The oxygenation of the MPVC ARDS animals was then compared to the oxygenation of the SPVC animals. Results Based on the comparisons, similar oxygenation and morbidity rates were observed between the MPVC ARDS animals and the SPVC animals. Conclusion As healthcare systems worldwide deal with inundated ICUs and hospitals from pandemics, they could potentially benefit from this approach by providing more patients with respiratory care. Supplementary Information The online version contains supplementary material available at 10.1007/s00540-021-02948-2.

Objective Currently, management of acute respiratory distress syndrome (ARDS) in COVID-19 infection with invasive mechanical ventilation results in poor prognosis and high mortality rates Interventions to reduce ventilatory requirements or preclude their needs should be evaluated in order to improve survival rates in critically ill patients Formation of neutrophil extracellular traps (NETs) during the innate immune response could be a contributing factor to the pulmonary pathology This study suggests the use of dornase alfa, a recombinant DNAse I that lyses NETs, to reduce ventilatory requirements and improve oxygenation status, as well as outcomes in critically ill patients with ARDS subsequent to confirmed or highly suspected COVID-19 infection Design A single-institution cohort study Setting Intensive care unit in a tertiary medical center Patients Adult patients with acute respiratory distress syndrome (ARDS) admitted to the ICU with confirmed COVID-19 infection Intervention Treatment with aerosolized dornase alfa Measurements and Main Results Of 39 patients evaluated, most patients had improvement in oxygenation measured by increase in the PaO2/FiO2 ratio, reduction in ventilatory support or other supportive oxygen requirements, and partial resolution of bilateral opacities visible on CXR, as well as improved outcome Conclusions Administration of inhalational dornase alfa via a filtered nebulizer medication system or through an adapter in a ventilator circuit should be considered in all COVID-19-positive patients with ARDS as early in the disease course as possible [ABSTRACT FROM AUTHOR] Copyright of Critical Care Research & Practice is the property of Hindawi Limited and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission However, users may print, download, or email articles for individual use This abstract may be abridged No warranty is given about the accuracy of the copy Users should refer to the original published version of the material for the full abstract (Copyright applies to all Abstracts )

OBJECTIVE To assess the effect of different frequencies of ventilator circuit changes in neonates and children through a systematic review and meta-analysis. INTERVENTIONS (1) "No routine change of ventilator circuit (unless visibly soiled)" versus "routine change at any fixed interval"; (2) routine change of circuit at "less frequent" versus "more frequent" intervals. OUTCOMES Primary outcomes were VAP rate (number of VAP episodes per 1000 ventilator-days) and all-cause mortality before discharge. METHODS MEDLINE, CENTRAL, EMBASE, and CINAHL were systematically searched from inception till November 3, 2020. Two authors assessed trial eligibility and risk of bias, and independently extracted data. Data were synthesized using fixed effects model. GRADE was used to assess certainty of evidence (CoE). RESULTS We identified six studies enrolling 768 participants evaluating circuit changes at two fixed intervals. Meta-analysis of studies on circuit changes "once in less than 7 days" versus "once weekly" showed no difference in VAP rate (risk ratio: 0.83 [0.38-1.81]; one randomized controlled trial (RCT) and 0.94 [0.49-1.81]; two before-after studies) or mortality before discharge (0.67 [0.34-1.3]; one RCT and 1.01 [0.63-1.64]; two before-after studies). CoE was very low. Less frequent circuit changes reduced health-care costs. No study evaluating "circuit changes only when visibly soiled" versus "circuit changes at a fixed interval" was identified. CONCLUSION There is no evidence to suggest that ventilator circuits can be safely left unchanged until visibly soiled in neonates and children. Extending circuit changes interval to "once weekly" may not increase VAP rate (CoE-very low) and reduces healthcare costs.

Background Gas conditioning minimizes complications associated with invasive ventilation of neonates. Poorly conditioned gas contributes to humidity deficit, facilitates condensate pools, and contributes to safety events. The specific aim was to objectively quantify the temperature drop across the unheated portion of a neonatal circuit and the impact condensation has to resistance to flow in the ventilator circuit. Methods Ventilator circuits and filters were obtained, assembled according to manufacturer recommendations, and operational verification procedures were performed prior to data collection. A neonatal test lung was connected to each Servo-I ventilator with the following settings: pressure control IMV mode; inspiratory pressure: 14 cm H2O to achieve an exhaled tidal volume of 6.0 mL; PEEP: 5 cm H2O; pressure support: 5 cm H2O, FIO2: 0.21; set frequency 40/min; and inspiratory time: 0.4 s. The Fisher and Paykel MR850 and ChonchaTherm Neptune heaters were set at a temperature of 40°C. To evaluate both systems under similar conditions, the ChonchaTherm Neptune heater humidity control was set to midline. Heaters were turned on simultaneously and given 1 h to equilibrate. Readings for room temperature, airway temperature at the patient connection, airway resistance, exhaled tidal volume, and direct observation of circuit condensation and (or) pooling were recorded hourly for a 48-h period. Summary statistics were calculated for the variables of interest. Results Mean (±SD) air temperature was 26.3°C (±1.4) for the Fisher & Paykel MR850 system and 26.2°C (±1.5), for the ChonchaTherm Neptune system. Mean (±SD) airway resistance was 229.3 cm H2O/L/s (±81.0) for the Fisher & Paykel system and 196.2 cm H2O/L/s (±39.4) for the ChonchaTherm Neptune system. Mean (±SD) tidal volume for the Fisher & Paykel MR850 system was 6.5 mL (±0.4), and for the ChonchaTherm Neptune system was 7.2 mL (±0.6). Conclusion Circuit condensate increased tidal volume delivery and airway resistance. Temperature at the patient connection was lower than the temperature monitored by the system 12 inches distally, which can negatively impact gas conditioning.

COVID-19 can cause serious respiratory complications resulting in the need for invasive ventilatory support and concurrent aerosol therapy. Aerosol therapy is considered a high risk procedure for the transmission of patient derived infectious aerosol droplets. Critical-care workers are considered to be at a high risk of inhaling such infectious droplets. The objective of this work was to use noninvasive optical methods to visualize the potential release of aerosol droplets during aerosol therapy in a model of an invasively ventilated adult patient. The noninvasive Schlieren imaging technique was used to visualize the movement of air and aerosol. Three different aerosol delivery devices: (i) a pressurized metered dose inhaler (pMDI), (ii) a compressed air driven jet nebulizer (JN), and (iii) a vibrating mesh nebulizer (VMN), were used to deliver an aerosolized therapeutic at two different positions: (i) on the inspiratory limb at the wye and (ii) on the patient side of the wye, between the wye and endotracheal tube, to a simulated intubated adult patient. Irrespective of position, there was a significant release of air and aerosol from the ventilator circuit during aerosol delivery with the pMDI and the compressed air driven JN. There was no such release when aerosol therapy was delivered with a closed-circuit VMN. Selection of aerosol delivery device is a major determining factor in the release of infectious patient derived bioaerosol from an invasively mechanically ventilated patient receiving aerosol therapy.

Rationale Mechanically ventilated patients must be disconnected from the ventilator during intra-facility transfers. Intentional and accidental circuit disconnections represent a potential hazard to patients (sudden collapse and re-expansion of the alveoli) as well as to clinical staff (exposure to patient's unfiltered exhalation). Therefore, avoiding abrupt circuit disconnections could better protect the patient's health and reduce or eliminate contamination risks around clinical staff. Objective The purpose of this in-vitro work was to investigate and evaluate the potential for environmental exposure of Nitric Oxide (NO, as an indicator of any contamination exposure) before and after implementing the novel Flusso™ Bypass adapter during the disconnect procedure of a mechanical ventilator system. Methods A mechanical ventilator delivering NO was connected to a breathing simulator with and without the Flusso™ Bypass adapter. The ambient NO concentration was measured when the circuit was briefly disconnected (3 s) during inhalation and exhalation. Both volume and pressure ventilation modes were used. Measurements and main results Disconnecting the standard ventilator circuit (pressure-controlled mode) without the Flusso™ Bypass adapter produced higher NO escape to the surroundings (compared with the volume-controlled mode), leading to a longer NO dissipation time. No ambient NO traces were detected when the Flusso™ adapter was used. Conclusion The usage of the Flusso™ adapter drastically decreases the unwanted exposure among clinical staff dealing with potentially hazardous airborne biological aerosols emanating from the circuit. Avoiding abrupt disconnection in the ventilator circuit could reduce lung injuries and alveolar over distension and collapse.

Background: The rapidly evolving COVID-19 pandemic has led to increased use of critical care resources, particularly mechanical ventilators. Amidst growing concerns that the health care system could face a shortage of ventilators in the future, there is a need for an affordable, simple, easy to use, emergency stockpile ventilator. Methods: Our team of engineers and clinicians designed and tested an emergency ventilator that uses a single limb portable ventilator circuit. The circuit is controlled by a pneumatic signal with electronic microcontroller input, using air and oxygen sources found in standard patient rooms. Ventilator performance was assessed using an IngMar ASL 5000 breathing simulator, and it was compared with a commercially available mechanical ventilator. Results: The emergency ventilator provides volume control mode, intermittent mandatory ventilation and continuous positive airway pressure. It can generate tidal volumes between 300 and 800 mL with

Purpose of review The aim of the article is to review the evidence to select ventilated patients most likely to benefit from inhaled antibiotic therapy and summarize the optimal implementation setup to favor clinical success. Recent findings Although a large body of literature describes the optimal ventilator circuit and settings to implement to favor a high amount of inhaled antibiotic delivery to ventilated patients, recent clinical trials failed to show a significant benefit on patient-centered outcomes. Currently, inhaled antibiotic therapy can only be recommended as a therapeutic modality of last resort after case-by-case discussion among specific patients or settings with high antimicrobial resistances. Summary Currently, inhaled antibiotic therapy may only be recommended to treat ventilator-associated pneumonia caused by extensively resistant bacteria only susceptible to colistin, and should be used either after documentation of such an infection or empirically in settings with a high probability of such an infection. A similar approach may be considered for aminoglycoside-only-susceptible pneumonia. In these cases, inhaled antibiotics should be ideally delivered as a complement to intravenous therapy placing a vibrating mesh nebulizer upstream in the inspiratory limb, reducing inspiratory flow and increasing inspiratory time, avoiding gas humidification under close clinical and pharmacological monitoring.

BACKGROUND Volatile anesthetics potentially trigger malignant hyperthermia crises in susceptible patients. We therefore aimed to identify preparation procedures for the Draeger Primus that minimize residual concentrations of desflurane and sevoflurane with and without activated charcoal filtration. METHODS A Draeger Primus test workstation was primed with 7% desflurane or 2.5% sevoflurane for 2 hours. Residual anesthetic concentrations were evaluated with five preparation procedures, three fresh gas flow rates, and three distinct applications of activated charcoal filters. Finally, non-exchangeable and autoclaved parts of the workstation were tested for residual emission of volatile anesthetics. Concentrations were measured by multicapillary column-ion mobility spectrometry with limits of detection/quantification being

BACKGROUND As the use of continuous high-frequency oscillation combined with nebulization during mechanical ventilation becomes more prevalent clinically, it is important to evaluate its aerosol delivery efficacy. METHODS A bench study was conducted that simulated 2 adult and 2 pediatric conditions. A continuous high-frequency oscillation device integrated into the inspiratory limb of a conventional critical care ventilator was attached to an endotracheal tube (ETT) with a collection filter and test lung. High-frequency oscillation with high-flow setting was used with jet nebulizers attached to the manifold, and a vibrating mesh nebulizer placed between the ETT and the ventilator circuit versus at the inlet of the humidifier. Albuterol (2.5 mg in 3 mL) was nebulized for each condition (no. = 3). The drug was eluted from the collection filter and assayed with ultraviolet spectrophotometry (276 nm). RESULTS During continuous high-frequency oscillation, the mean inhaled dose with jet nebulizers was low (

The present emergency caused by the spread of the COVID-19 infection is putting enormous pressure on the healthcare systems worldwide and especially on intensive care units (ICUs). One of the main fears in this regard is that we may run out of ventilators, a possibility which is getting more and more likely as the pandemic spreads throughout the world and the ICUs are overloaded with ventilated patients. Many authors have already investigated the possibility of manipulating a ventilator circuit in order to ventilate up to four patients with a single machine. Neyman and Ervin first performed a bench study demonstrating the technical feasibility of ventilating four patients with one ventilator and one modified circuit.1 The same circuit configuration was used in 2008 by Paladino et al in an animal model, resulting in substantial differences in oxygenation and decarboxylation between subjects during the ventilation period.2 In 2012 Branson et al tested in vitro the Neyman and Ervin system simulating different conditions of compliance and resistance between the simultaneously ventilated test lungs. They observed wide variability in measured tidal volume (Vt) and end-expiratory lung volume, so they concluded that the technique should be avoided because of potential danger.3 Accordingly, the authors argued that the stockpiling of ventilators should be the first-line solution when massive emergencies are forecast; only after their depletion, strategies such as the ‘double circuit’ should be implemented for the shortest possible duration.4 5 On 20 February 2020, the first case of COVID-19 emerged in the Lombardy region, northern Italy. As of 17 March, a total of 1069 patients had been admitted …

BACKGROUND: Noninvasive ventilation (NIV) is used to treat respiratory failure in patients with concomitant need for aerosol delivery. Limited pediatric data are available on aerosol delivery efficiency, and none at all regarding aerosol delivery efficiency with a double-limb circuit. We compared the effect of position in the double-limb ventilator circuit, types of nebulizer, and ventilator settings on aerosol delivery efficiency in a pediatric model of NIV. We hypothesized that placing a vibrating mesh nebulizer at the ventilator and using the highest inspiratory pressures would increase aerosol delivery efficiency. METHODS: A breathing simulator was connected in series to a low dead-space filter holder (lung dose) and to an anatomically correct head/airway model of a 5-year-old child. A non-vented mask connected the model to a ventilator operated on noninvasive bi-level mode and assembled with a double-limb, heated-wired adult circuit. Inspiratory pressures of either 15 or 20 cm H 2 O and an expiratory pressure of 5 cm H 2 O were used. Two different vibrating mesh nebulizers and 2 different jet nebulizers loaded with albuterol solution were studied. Albuterol was measured with spectrophotometry. Aerosol delivery efficiency was calculated as lung dose expressed as a percentage of the nominal dose. RESULTS: A vibrating mesh nebulizer before the mask or Y-piece provided the highest delivery efficiency and outperformed a vibrating mesh nebulizer integrated into the mask. Vibrating mesh nebulizers delivered more drug than jet nebulizers, regardless of their position in the circuit. Increasing the inspiratory pressure only improved aerosol delivery efficiency with a jet nebulizer placed at the ventilator. CONCLUSIONS: In a pediatric model of NIV, the effect of nebulizer position on aerosol delivery efficiency depends on the type of device and its placement in the ventilator circuit. A vibrating mesh nebulizer placed at the mask or before the Y-piece of the double-limb circuit provided the highest aerosol drug delivery during NIV. Data generated with invasive ventilation models should not be generalized to NIV models.

Much evidence supports the use of non-invasive ventilation (NIV) in patients who have acute and chronic respiratory failure and aerosolized medications are increasingly used in this patient population. Successful application of aerosol therapy during NIV depends on the effectiveness of the drug deposition in the lungs. Previous evidence showed that many factors impact aerosol delivery to patients receiving NIV. Those factors include mode of ventilation, ventilator parameters, type of ventilator circuit, the position of the aerosol device, the location of leak port, type of exhalation valve, humidity, enhanced condensational growth, type of aerosol device, and interface as well as delivery technique. The purpose of this paper is to review the available evidence related to aerosol therapy during NIV and provide recommendations to optimize aerosol drug delivery to patients receiving NIV.

INTRODUCTION: Adequate oxygenation is one of the primary goals of mechanical ventilation. Maintenance of adequate oxygenation and prevention of hypoxemia are the primary goals for the battlefield casualty, but military operations have unique concerns. In military operations, oxygen is a limited resource. A portable oxygen concentrator has the advantage of operating solely from electrical power and theoretically is a never-exhausting supply of oxygen. Our previous bench work demonstrated that the pulsed dose setting of the concentrator can be used in concert with the ventilator to maximize oxygen delivery. We evaluated this ventilator/concentrator system with closed loop control of oxygen output in a porcine model. MATERIALS AND METHODS: The Zoll 731 portable ventilator and Sequal Saros portable oxygen concentrator were used for this study. The ventilator and concentrator were connected via a USB cable to allow communication. The ventilator was modified to allow closed loop control of oxygen based on the oxygen saturation (SpO2) via the integral pulse oximetry sensor. The ventilator communicates with the concentrator to increase or decrease oxygen bolus size to maintain a target SpO2 of 94%. Three separate experiments were conducted in this study. Experiments 1 and 2 used oxygen bolus sizes 16-96 mL in 16-mL increments and experiment 3 used 1 mL increments. The oxygen bolus was delivered from the concentrator and injected into the ventilator circuit at the patient connector. Six pigs were used for each experiment. Experiment 1, done without lung injury, was completed to determine the optimum timing during the respiratory cycle for injecting the oxygen bolus. Lung injury for experiments 2 and 3 was induced in the animals by warmed saline lavage via the endotracheal tube until PaO2/FIO2 decreased to

Introduction: Wooden chest syndrome (WCS) is a rare and often fatal reaction to fentanyl where airways and chest wall musculature become rigid through α1-noradrenergic activation and cholinergic modulation causing ineffective ventilation.1-4 This dose-independent response is more easily diagnosed in non-ventilated patients either in the operating room or who overdose recreationally.2,4,5 In ventilated patients with acute respiratory distress syndrome (ARDS) it can be difficult to distinguish from poor lung compliance. We describe a case of a previously healthy male with COVID-19 on mechanical ventilation who developed WCS.Case: A 47-year-old previously healthy male was admitted for COVID-19 pneumonia requiring high-flow nasal cannula. On hospital day 11, he was intubated and placed on lung protective ventilation for moderate ARDS (PaO2/FiO2 192). On ventilator day (VD) 2 a fentanyl infusion was started. After 36 hours, hypoxemia improved but plateau pressures were consistently

Background The current coronavirus infectious disease 2019 (COVID-19) pandemic has caused unexpected pressure on medical supplies, interrupting supply chains and increasing prices. The supply of antiviral filters which form an essential part of the ventilator circuit have been affected by these issues. Three-dimensional (3D) printing may provide a solution to some of these issues. Methods We designed and tested 3D printed heat and moisture exchange (HME) and antiviral casing. For each casing we tested two different filter materials derived from a sediment water filter cartridge or 1.5-μm glass fiber filter paper. A polyurethane sponge was used for the HME. Each design was tested for circuit leak, circuit compliance, peak inspiratory pressure and casing integrity using methylene blue dye. Results We designed, produced, and tested two different types of antiviral filters with six different internal configurations. Overall, we tested 10 modified filter designs and compared them with the original commercial filter. Except for the combination of 1.5-μm filter paper and 5 mm sponge peak inspiratory pressure and circuit compliance of the filters produced were within the operating limits of the ventilator. All In addition, all filters passed the dye test. Conclusions Our filter may be of particular importance to those working in low middle-income countries unable to compete with stronger economies. Our design relies on products available outside the healthcare supply chain, much of which can be purchased in grocery stores, hardware stores, or industrial and academic institutions. We hope that these HMEs and viral filters may be beneficial to clinicians who face critical supply chain issues during the COVID-19 pandemic.

Background: The effect of different interfaces on the aerosol delivery with vibrating mesh nebulizer during noninvasive positive pressure ventilation (NIV) is not clear. Materials and Methods: Noninvasive ventilator and four interfaces were connected to IngMar ASL 5000 lung simulator. Meanwhile, the vibrating mesh nebulizer was connected to a ventilator circuit to simulate the nebulization during noninvasive ventilation. The nebulizer position was placed at proximal position (near the mask) and distal position (15 cm away from the mask); the inspiratory positive airway pressure (IPAP) and the expiratory positive airway pressure (EPAP) were set to 16/4, 16/8, 20/4, and 20/8 cmH2O, respectively. The aerosol was collected through a disposable filter placed between the simulated lung and the mask, after which the aerosol delivery was calculated. Meanwhile, we recorded the inspiratory tidal volume and the mean inspiratory flow. Results: The aerosol delivery varied between 1.7% ± 0.0% and 21.1% ± 1.1%. Only when EPAP was set to 4 cmH2O, the statistical difference in aerosol delivery was observed between the two types of interface, and between different leak port locations (p < 0.01; p = 0.04, respectively). When IPAP/EPAP was set to 16/4 and 20/4 cmH2O, respectively, at different nebulizer positions, there was a statistical difference between the interface with the same type but different leak port locations and between the interface with same leak port location but different inner volumes (all p < 0.01). Also, there was a correlation between the aerosol delivery and interface volume (p < 0.01, R2 = 0.55; p < 0.01, R2 = 0.51, respectively), and between aerosol delivery and the intentional leak of interfaces (p < 0.01, R2 = 0.59; p < 0.01, R2 = 0.48, respectively). When EPAP was set to 4 and 8 cmH2O, respectively, the aerosol delivery of nebulizer distal position was significantly higher than that of proximal position (12.2% ± 5.0% vs. 9.1% ± 4.1%, p < 0.05; 2.5% ± 0. 5% vs. 2.1% ± 0.3%, p < 0.01, respectively). Conclusion: Interfaces have a significant effect on aerosol delivery during NIV. The interfaces with different inner volumes, intentional leak, and leak port location may all have an effect on aerosol delivery. The addition of a 15 cm tube between the nebulizer and the mask significantly increases the aerosol delivery.

Introduction: In mechanically ventilated patients, ventilator-associated pneumonia (VAP) is a major cause of prolonged hospitalization with increased morbidity and mortality. There is a lack of studies on the relationship between bacterial colonization of the ventilator circuit (VC) and VAP. This study aimed to investigate the role of bacterial colonization of VC in the development of VAP and identify antibiotic susceptibility trends for isolated strains. Methods: A prospective study of the bacterial culture has been performed between February 2021 to March 2021 on a total of 100 mechanically ventilated patients, (n =50) samples have been obtained from patient's lower respiratory tract (LRT) and (n =50) were taken from mechanical ventilator equipment VC. Paired samples of bacteria isolated from VC and LRT, where VC was colonized before LRT. Results: A total of 58 samples were cultured positively, while 42 specimens showed negative bacterial growth. However, there was no substantial difference in comparing between the bacterial colonization of the ventilator system and the patient samples. Most isolated organisms were gram-negative bacteria which were found in the ventilator circuit with 26 (68.4%), and 14 (70%) in patient’s LRT. Gram-positive was detected in 12 (31.6%) and 6 (30%) of the ventilator circuit, and patient's LRT, respectively. The predominant bacterial type was Acinetobacter baumannii organism at the VC with 10 (26.3%) and LRT at 4 (20%) followed by Klebsiella pneumoniae (8 (21.1%) in VC and 4 (20%) in LRT). Moreover, A. baumannii showed a full resistance to amoxicillin and the first generation of cephalosporins, while the other bacterial types were resistant to the most antibiotics used in this research. Conclusions: Bacterial colonization of ventilator circuit VC is a significant cause of VAP development in mechanically ventilated patients. Preventive strategies for the early detection and decontamination of contaminated VC can play a crucial role in ventilator-associated pneumonia prevention., {"references":["Vincent JL, Bihari DJ, Suter PM, Bruining HA, White J, Nicolas-Chanoin MH, et al. The prevalence of nosocomial infection in intensive care units in Europe. Results of the European Prevalence of Infection in Intensive Care (EPIC) Study. EPIC International Advisory Committee. JAMA. 1995;274(8):639-44.","Esteban A, Anzueto A, Alía I, Gordo F, Apezteguía C, Pálizas F, et al. How is mechanical ventilation employed in the intensive care unit? An international utilization review. Am J Respir Crit Care Med. 2000;161(5):1450-8. doi: 10.1164/ajrccm.161.5.9902018.","Levin PD, Shatz O, Sviri S, Moriah D, Or-Barbash A, Sprung CL, et al. Contamination of portable radiograph equipment with resistant bacteria in the ICU. Chest. 2009;136(2):426-32. doi: 10.1378/chest.09-0049.","Esteban A, Anzueto A, Frutos F, Alía I, Brochard L, Stewart TE, et al. Characteristics and outcomes in adult patients receiving mechanical ventilation: a 28-day international study. JAMA. 2002;287(3):345-55. doi: 10.1001/jama.287.3.345.","Hess DR, Kallstrom TJ, Mottram CD, Myers TR, Sorenson HM, Vines DL, et al. Care of the ventilator circuit and its relation to ventilator-associated pneumonia. Respir Care. 2003;48(9):869-79.","Craven DE, Goularte TA, Make BJ. Contaminated condensate in mechanical ventilator circuits. A risk factor for nosocomial pneumonia? Am Rev Respir Dis. 1984;129(4):625-8.","Li YC, Lin HL, Liao FC, Wang SS, Chang HC, Hsu HF, et al. Potential risk for bacterial contamination in conventional reused ventilator systems and disposable closed ventilator-suction systems. PLoS One. 2018;13(3):e0194246. doi: 10.1371/journal.pone.0194246.","Hospital-acquired pneumonia in adults: diagnosis, assessment of severity, initial antimicrobial therapy, and preventive strategies. A consensus statement, American Thoracic Society, November 1995. Am J Respir Crit Care Med. 1996;153(5):1711-25. doi: 10.1164/ajrccm.153.5.8630626.","Porzecanski I, Bowton DL. Diagnosis and treatment of ventilator-associated pneumonia. Chest. 2006;130(2):597-604. doi: 10.1378/chest.130.2.597.","Kalanuria AA, Ziai W, Mirski M. Ventilator-associated pneumonia in the ICU. Crit Care. 2014;18(2):208. doi: 10.1186/cc13775.","Wroblewska MM, Swoboda-Kopec E, Rokosz A, Krawczyk E, Marchel H, Luczak M. Epidemiology of clinical isolates of Candida albicans and their susceptibility to triazoles. Int J Antimicrob Agents. 2002;20(6):472-5. doi: 10.1016/s0924-8579(02)00246-7.","Geffers C, Zuschneid I, Sohr D, Rüden H, Gastmeier P. [Microbiological isolates associated with nosocomial infections in intensive care units: data of 274 intensive care units participating in the German Nosocomial Infections Surveillance System (KISS)]. Anasthesiol Intensivmed Notfallmed Schmerzther. 2004;39(1):15-9. doi: 10.1055/s-2004-815713.","Namias N, Samiian L, Nino D, Shirazi E, O'Neill K, Kett DH, et al. Incidence and susceptibility of pathogenic bacteria vary between intensive care units within a single hospital: implications for empiric antibiotic strategies. J Trauma. 2000;49(4):638-45; discussion 645-6. doi: 10.1097/00005373-200010000-00010.","Winarto W. Prevalence of Extended-Spectrum β-lactamases (ESBL)-bacteria of Blood Isolates in Dr. Kariadi Hospital Semarang 2004-2005. M Med Indones. 2009;43(5):260-8.","Tan R, Liu J, Li M, Huang J, Sun J, Qu H. Epidemiology and antimicrobial resistance among commonly encountered bacteria associated with infections and colonization in intensive care units in a university-affiliated hospital in Shanghai. J Microbiol Immunol Infect. 2014;47(2):87-94. doi: 10.1016/j.jmii.2012.11.006.","Srinivasan R, Asselin J, Gildengorin G, Wiener-Kronish J, Flori HR. A prospective study of ventilator-associated pneumonia in children. Pediatrics. 2009;123(4):1108-15. doi: 10.1542/peds.2008-1211.","Forbes BA, Sahm DF, Weissfeld AS. Bailey & Scott's Diagnostic Microbiology - Text and Study Guide Package. 12th ed. New York: Elsevier; 2007.","Mahon C, Lehman D. Textbook of Diagnostic Microbiology. 6th ed. New York: USA; 2019.","Munoz-Price LS, Weinstein RA. Acinetobacter infection. N Engl J Med. 2008;358(12):1271-81. doi: 10.1056/NEJMra070741.","Siani H, Maillard JY. Best practice in healthcare environment decontamination. Eur J Clin Microbiol Infect Dis. 2015;34(1):1-11. doi: 10.1007/s10096-014-2205-9.","Kanamori H, Weber DJ, Rutala WA. Healthcare Outbreaks Associated With a Water Reservoir and Infection Prevention Strategies. Clin Infect Dis. 2016;62(11):1423-35. doi: 10.1093/cid/ciw122.","Morgan DJ, Liang SY, Smith CL, Johnson JK, Harris AD, Furuno JP, et al. Frequent multidrug-resistant Acinetobacter baumannii contamination of gloves, gowns, and hands of healthcare workers. Infect Control Hosp Epidemiol. 2010;31(7):716-21. doi: 10.1086/653201.","Craven DE, Connolly MG Jr, Lichtenberg DA, Primeau PJ, McCabe WR. Contamination of mechanical ventilators with tubing changes every 24 or 48 hours. N Engl J Med. 1982;306(25):1505-9. doi: 10.1056/NEJM198206243062501.","Radji M, Fauziah S, Aribinuko N. Antibiotic sensitivity pattern of bacterial pathogens in the intensive care unit of Fatmawati Hospital, Indonesia. Asian Pac J Trop Biomed. 2011;1(1):39-42. doi: 10.1016/S2221-1691(11)60065-8.","Werarak P, Kiratisin P, Thamlikitkul V. Hospital-acquired pneumonia and ventilator-associated pneumonia in adults at Siriraj Hospital: etiology, clinical outcomes, and impact of antimicrobial resistance. J Med Assoc Thai. 2010;93 Suppl 1:S126-38.","Yoo JH, Choi JH, Shin WS, Huh DH, Cho YK, Kim KM, et al. Application of infrequent-restriction-site PCR to clinical isolates of Acinetobacter baumannii and Serratia marcescens. J Clin Microbiol. 1999;37(10):3108-12. doi: 10.1128/JCM.37.10.3108-3112.1999.","Schulz-Stübner S, Schmidt-Warnecke A, Hwang JH. VRE transmission via the reusable breathing circuit of a transport ventilator: outbreak analysis and experimental study of surface disinfection. Intensive Care Med. 2013;39(5):975-6. doi: 10.1007/s00134-013-2842-y."]}

In comparison with spontaneously breathing non-intubated subjects, intubated, mechanically ventilated patients encounter various challenges, barriers, and opportunities in receiving medical aerosols. Since the introduction of mechanical ventilation as a part of modern critical care medicine during the middle of the last century, aerosolized drug delivery by jet nebulizers has become a common practice. However, early evidence suggested that aerosol generators differed in their efficacies, and the introduction of newer aerosol technology (metered dose inhalers, ultrasonic nebulizer, vibrating mesh nebulizers, and soft moist inhaler) into the ventilator circuit opened up the possibility of optimizing inhaled aerosol delivery during mechanical ventilation that could meet or exceed the delivery of the same aerosols in spontaneously breathing patients. This narrative review will catalogue the primary variables associated with this process and provide evidence to guide optimal aerosol delivery and dosing during mechanical ventilation. While gaps exist in relation to the appropriate aerosol drug dose, discrepancies in practice, and cost-effectiveness of the administered aerosol drugs, we also present areas for future research and practice. Clinical practice should expand to incorporate these techniques to improve the consistency of drug delivery and provide safer and more effective care for patients.