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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.

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.

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. 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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.

Mechanical ventilation bypasses the protective mechanisms of the upper respiratory tract which are designed to heat and humidify inspired air to 37 °C and 44 mg H2O/L respectively. Artificial humid...

COVID-19 may lead to serious respiratory complications which may necessitate ventilatory support. There is concern surrounding potential release of patient-derived bioaerosol during nebuliser drug refill, which could impact the health of caregivers. Consequently, mesh nebulisers have been recommended by various clinical practice guidelines. Currently, there is a lack of empirical data describing the potential for release of patient-derived bioaerosol during drug refill. This study examined the release of simulated patient-derived bioaerosol, and the effect on positive end expiratory pressure during nebuliser refill during mechanical ventilation of a simulated patient. During jet nebuliser refill, the positive end expiratory pressure decreased from 4.5 to 0 cm H2O. No loss in pressure was noted during vibrating mesh nebuliser refill. A median particle number concentration of 710 particles cm−3 above ambient was detected when refilling the jet nebuliser in comparison to no increase above ambient detected when using the vibrating mesh nebuliser. The jet nebuliser with the endotracheal tube clamped resulted in 60 particles cm−3 above ambient levels. This study confirms that choice of nebuliser impacts both the potential for patient-derived bioaerosol release and the ability to maintain ventilator circuit pressures and validates the recommended use of mesh nebulisers during mechanical ventilation.

During the recent CoVID-19 pandemic, airway management recommendations have been provided to decrease aerosolization and risk of viral spread to healthcare providers. High efficiency particulate air (HEPA) viral filters and adaptors are one way to decrease the risk of aerosolization during intubation. When placed proximal to the ventilator circuit, these viral filters and adaptors can create a significant amount of dead space, which in our smallest patients can significantly impact effective ventilation. We report a case of hypoventilation in a pediatric patient due to lack of provider team appreciation or ventilator sensing of additional dead space due to HEPA viral filter and adaptor.

Introduction. The rapidly spreading Novel Coronavirus 2019 (COVID-19) appeared to be a highly transmissible pathogen in healthcare environments and had resulted in a significant number of patients with respiratory failure requiring tracheostomy, an aerosol-generating procedure that places healthcare workers at high risk of contracting the infection. Instead of deferring or delaying the procedure, we developed and implemented a novel percutaneous dilatational tracheostomy (PDT) protocol aimed at minimizing the risk of transmission while maintaining favorable procedural outcome. Patients and Methods. All patients who underwent PDT per novel protocol were included in the study. The key element of the protocol was the use of apnea during the critical part of the insertion and upon any opening of the ventilator circuit. This was coupled with the use of enhanced personnel protection equipment (PPE) with a powered air-purifying respirator (PAPR). The operators underwent antibody serology testing and were evaluated for COVID-19 symptoms two weeks from the last procedure included in the study. Results. Between March 12th and June 30th, 2020, a total of 32 patients underwent PDT per novel protocol. The majority (80%) were positive for COVID-19 at the time of the procedure. The success rate was 94%. Only one patient developed minor self-limited bleeding. None of the proceduralists developed positive serology or any symptoms compatible with COVID-19 infection. Conclusion. A novel protocol that uses periods of apnea during opening of the ventilator circuit along with PAPR-enhanced PPE for PDT on COVID-19 patients appears to be effective and safe for patients and healthcare providers.

Background Aerosolized drug therapy administered to mechanically ventilated patients is a standard part of pulmonary critical care medicine. Aerosol particle size and distribution are important factors in the optimal delivery of aerosolized drugs to ventilated patients. Objective The objective of this study was to characterize aerosol droplet size and distribution with laser diffraction for nebulized 3% sodium chloride, albuterol, and epoprostenol sodium (containing glycine) delivered via Aeroneb Solo Mesh Nebulizers (Aerogen, Mountain View, California). Methods A series of functional flow tests were run on each of 8 Solo mesh nebulizers before the study to verify accuracy of flow rates in milliliters per minute. Aerosolized droplets exiting the nebulizer heads were then measured using a phase Doppler particle analyzer. Data collected during delivery of 3% sodium chloride, albuterol, and epoprostenol sodium included aerosol droplet size distribution, mass median aerodynamic diameter (MMAD), and geometric standard deviation. For each Solo nebulizer, droplet size measurements were taken 2 cm away from the nebulizer head and 2 cm away from the wye of a heated, humidified adult ventilator circuit. For measurements taken at the wye, 4 distinct, continuous flow rates (2, 10, 20, and 40 L/min) were generated by an air pump to simulate inspiratory flows delivered with mechanical ventilation. The expiratory limb was capped, and the nebulizer head was inserted into the breathing circuit upstream of the humidifier. Results Each Solo nebulizer met Aerogen's recommended minimum flow rate of 0.2 mL/min, ranging from 0.23 to 0.31 mL/min. The MMAD of the 3 tested aerosols was several times smaller when measured at the wye outlet of the heated/humidified breathing circuit (0.82–2.73 µm) compared with droplets measured directly at the nebulizer outlet (MMAD, 4.6–7.3 µm). There was also significant variability across Solo heads with some ventilator flow rates. The mean MMAD at the wye for the 3% sodium chloride solution, albuterol, and epoprostenol test solutions was 1.62 µm, 1.09 µm, and 1.18 µm, respectively. The mean MMAD at the nebulizer for the 3% sodium chloride solution, albuterol, and epoprostenol test solutions was 5.37 µm, 5.73 µm, and 6.73 µm, respectively. Conclusions Results from this study suggest that particle size of aerosolized drugs administered via a commonly used setup for delivery of in-line aerosols to mechanically ventilated patients may be several times smaller than expected and may result in less drug being delivered to the patient than previously realized. (Curr Ther Res Clin Exp. 2021; 82:XXX–XXX) © 2021 Elsevier HS Journals, Inc.

Interruptions in continuous nebulized pulmonary vasodilators, such as epoprostenol, can potentially result in clinical deterioration in respiratory status. Coadministration of other intermittent nebulized therapies may require opening the ventilator circuit to facilitate administration. However, in patients with SARS-CoV2 infection, it is preferred to avoid opening the circuit whenever feasible to prevent aerosolization of the virus and exposure of health care workers. In this study, we describe a unique method of administering continuous epoprostenol nebulization and intermittent nebulized antibiotics, mucolytics, and bronchodilators, using Aerogen vibrating mesh nebulizers without interruptions in epoprostenol or opening the ventilator circuit. This technique set up consisted of stacking two Aerogen nebulizer cups, each with its own controller. This approach was successful in allowing concomitant delivery of intermittent and continuous nebulized therapy without interruptions. To our knowledge, this method has not been previously described in the literature and may be helpful to bedside clinicians facing a similar clinical scenario.

BackgroundDisasters have the potential to cause critical shortages of life-saving equipment. It has been postulated that during patient surge, multiple individuals could be maintained on a single ventilator. This was supported by a previous trial that showed one ventilator could support four sheep. The goal of our study is to investigate if cross contamination of pathological agents occurs between individuals on a shared ventilator with strategically placed antimicrobial filters.MethodsA multipatient ventilator circuit was assembled using four sterile, parallel standard tubing circuits attached to four 2 L anaesthesia bags, each representing a simulated patient. Each ‘patient’ was attached to a Heat and Moisture Exchange filter. An additional bacterial/viral filter was attached to each expiratory limb. ‘Patient-Lung’ number 1 was inoculated with an isolate of Serratia marcescens, and the circuit was run for 24 hours. Each ‘lung’ and three points in the expiratory limb tubing were washed with broth and cultured. All cultures were incubated for 48 hours with subcultures performed at 24 hours.ResultsWashed cultures of patient 2, 3 and 4 failed to demonstrate growth of S. marcescens. Cultures of the distal expiratory tubing, expiratory limb connector and expiratory limb prefilter tubing yielded no growth of S. marcescens at 24 or 48 hours.ConclusionBased on this circuit configuration, it is plausible to maintain four individuals on a single ventilator for 24 hours without fear of cross contamination.

BackgroundNosocomial transmission of SARS-CoV-2 has been a major cause of morbidity and mortality in the COVID-19 pandemic. Emerging evidence suggests patients auto-emit aerosols containing viable respiratory viruses. These aerosols could be further propagated when patients undergo certain treatments including continuous positive airway pressure (PAP) therapy. This study aimed to assess the degree of viable virus propagated from mask leak in a PAP circuit and the mitigation of virus propagation by an air filter combined with a plastic canopy.MethodsBacteriophage PhiX174 (108copies/mL) was nebulised into a custom PAP circuit within a non-vented clinical room. Mask leak was systematically varied to allow 0, 7, 21, 28 and 42 L/min at the mask interface. Plates containing Escherichia coli host assessed the degree of viable virus (via plaque forming unit) settling on surfaces around the room. In order to contain virus spread, the efficacy of a simple, low-cost ventilated headboard, created from a plastic tarpaulin hood and a high efficiency particulate air (HEPA) filter was tested.FindingsIncreasing mask leak was associated with virus contamination in a dose response manner (χ2 = 58.24, df = 4, p< 0.001). Clinically relevant levels of leak (≥21 L/min) were associated with virus counts equivalent to using PAP with a standard vented mask. The highest frequency of viruses was detected on surfaces 1m from the leak source, however, viable viruses were recorded on all plates (up to 3.86m from source). A plastic hood with HEPA filtration significantly reduced viable viruses on all plates. HEPA exchange rates of 170 and 470m3/hr eradicated all evidence of virus contamination.InterpretationMask leak from PAP circuits may be a major source of environmental contamination and nosocomial spread of infectious respiratory diseases. Subclinical levels of leak should be treated as an infectious risk. Cheap and low-cost patient hoods with HEPA filtration are an effective countermeasure.FundingNational Health and Medical Research Council of Australia (1139745).RESEARCH IN CONTEXTEvidence before this studyNosocomial spread of SARS-CoV-2 results in increased infection rates among healthcare workers compared to the general population. Those workers involved in the delivery of non-invasive ventilation are at higher risk based on evidence from previous SARS outbreaks. However, little is known about virus aerosol spread and environmental contamination from respiratory interventions like non-invasive ventilation, which is one of few life-saving treatments for COVID-19 patients. We therefore searched through PubMed with no language restrictions from inception to August 21, 2020 using the search terms ([NIV] or [non-invasive ventilation] or [noninvasive ventilation] or [CPAP] or [continuous positive airways pressure] or [PAP] or [positive airways pressure]) and ([aerosol spread] or [aerosol dispersion] or [aerosol generation]). The search returned 130 publications of which 28 related to the generation or spread of aerosols. Of the 28 related papers, 17 were consensus or opinion papers, 4 were reviews and 7 were original research papers. All previous studies investigating aerosol propagation with respiratory interventions utilised particle sizers or smoke visualisation techniques. These methodological limitations mean that particles are counted or visualised close to the aerosol source and reveal little about wider aerosol spread. Furthermore, they ignore the inherent biological aspects of viral aerosol dispersion in that the aerosol needs to contain viable virus in order to be infectious. It has not been directly established that clinical respiratory interventions are capable of propagating viable virus aerosol and no attempt has been made to systematically quantify the degree of environmental contamination from viable virus aerosol escaping from non-invasive ventilation circuits. There are no current studies informing us as to the effectiveness of air filtration interventions at mitigating environmental contamination with viable virus aerosol escaping from non-invasive ventilation circuits.Added value of this studyOur study quantifies the degree of viable virus aerosol spread from clinically relevant levels of noninvasive ventilator circuit mask leak, and demonstrates a risk mitigation strategy using a hood and air-purifier at completely eliminating viable virus aerosol environmental contamination. We developed a viable virus aerosol model utilising bacteriophage PhiX174 which is similar in size to SARS-CoV-2 and is harmless to humans. Through nebulising a solution of PhiX174 into a custom ventilation circuit with controllable mask leak settings, we were able to demonstrate that increasing circuit leak was associated with environmental virus contamination in a dose response manner (p< 0.001). Even sub-clinically apparent levels of circuit leak (< 7L/min) were associated with detectable virus propagation up to 3.86 metres from the leak source. Deployment of a hood and air-purifier setup as described by the United States Centres for Disease Control and Prevention, completely eliminated environmental virus contamination from viral aerosol dispersion.Implications of all the available evidenceNon-invasive ventilator circuit mask leak can propagate live virus containing aerosol and can lead to extensive environmental contamination up to 3.86 metres from the leak source, even at levels of leak that would be difficult to detect clinically. This raises important safety considerations for open wards delivering non-invasive ventilatory support and could explain the noted increased risk of nosocomial SARS infections in healthcare workers delivering non-invasive ventilation treatment. Point of emission air filtration with simple hood and air-purifier completely eliminates environmental contamination with viable virus and could be readily deployed to protect health care workers in the COVID-19 pandemic.

Supplemental Digital Content is available in the text., Objectives: To design and test a ventilator circuit that can be used for ventilation of two or more patients with a single ventilator, while allowing individualization of tidal volume, fractional concentration of oxygen, and positive end-expiratory pressure to each patient, irrespective of the other patient’s respiratory system mechanics. Design: Description and proof of concept studies. Settings: Respiratory therapy laboratory. Subjects: Ventilation of mechanical test lungs. Interventions: Following a previously advocated design, we used components readily available in our hospital to assemble two “bag-in-a-box” breathing circuits. Each patient circuit consisted of a flexible bag in a rigid container connected via one-way valve to a test lung, along with an inline positive end-expiratory pressure valve, connected to the ventilator’s expiratory limb. Compressed gas fills the bags during “patient” exhalation. During inspiration, gas from the ventilator, in pressure control mode, enters the containers and displaces gas from the bags to the test lungs. We varied tidal volume, “respiratory system” compliance, and positive end-expiratory pressure in one lung and observed the effect on the tidal volume of the other. Measurements and Main Results: We were able to obtain different tidal volume, dynamic driving pressure, and positive end-expiratory pressure in the two lungs under widely different compliances in both lungs. Complete obstruction, or disconnection at the circuit connection to one test lung, had minimal effect (< 5% on average) on the ventilation to the co-ventilated lung. Conclusions: A secondary circuit “bag-in-the-box” system enables individualized ventilation of two lungs overcoming many of the concerns of ventilating more than one patient with a single ventilator.

We are in a crisis where healthcare providers on the frontlines are running out of the appropriate personal protective equipment including N95 masks and power air-purifying respirators. Here, we propose a makeshift filter mask that we call the Modified Airway from VEntilatoR Circuit (MAVerIC) that can be assembled within seconds using widely available supplies routinely utilized by anesthesia providers in the operating room to provide practitioners on the frontlines with the high standard of protection of a N95 mask during the coronavirus disease 2019 (COVID-19) pandemic, and can be easily quantitatively "fit tested" to ensure no significant leak to optimize safety and efficacy.

Introdução: A pneumonia associada a ventilação mecânica é a segunda causa de infecção em pacientes de unidade de terapia intensiva causando altas taxas de mortalidade e de custos hospitalares. O objetivo deste estudo foi identificar na literatura os cuidados mais importantes para prevenir pneumonia associada a ventilação mecânica. Metodologia: Trata-se de estudo exploratório em fontes secundárias, com abordagem qualitativa e utilização do método de revisão integrativa. Resultados: Obteve-se amostragem de 18 artigos publicados, os cuidados considerados mais importantes para prevenção de pneumonia associada a ventilação mecânica adotados pelos profissionais de saúde foram: higiene oral (94,4%), elevação da cabeceira no leito 30º- 45º (77,7%), pressão do cuff (66,6%), aspiração de secreção subglótica (55,5%), manutenção do circuito do ventilador (38,85) e higienização das mãos (33,3%). Conclusão: O estudo mostra a importância da aplicação destes cuidados para redução na taxa de incidência de pneumonia associada a ventilação mecânica, no tempo de uso do ventilador mecânico e de permanência na unidade de terapia intensiva. E revela que o cuidado menos realizado pelos profissionais é a higienização das mãos considerado um cuidado simples, prático e eficaz para a prevenção de infecções hospitalares.

In the current COVID-19 crisis, the US and many countries in the world are suffering acute shortages of modern ventilators to care for desperately ill patients. Since modern ICU ventilators are powerful devices that can deliver very high gas flow rates and pressures, multiple physicians have attempted to ventilate more than one patient on a single ventilator – so-called “vent splitting”. Early applications of this approach have utilized simple concatenations of ventilator tubing and T-pieces, to provide flow to more than one patient. Additional approaches using custom flow splitters – sometimes made using 3D printing technologies – have also advanced into the clinic with FDA approval. However, heretofore there has been less progress made on controlling individual ventilatory pressures for patients with severe lung disease. Given the inherent variability and instability of lung compliance amongst patients with COVID-19, there remains an important need to provide a means of extending ventilator usefulness to more than one patient, but in a way that provides more tailored pressures that can be titrated over time. In this descriptive report, we provide the basis for a ventilator circuit that can support two patients with individualized peak inspiratory and end-expiratory pressures. The circuit is comprised of exclusively “off the shelf” materials and is inexpensive to produce. The circuit can be used with typical ICU ventilators, and with anesthesia ventilators used in operating rooms. Inspiratory and end-expiratory pressures for each patient can be titrated over time, without changes for one patient affecting the ventilation parameters of the other patient. Using in-line spirometry, individual tidal volumes can be measured for each patient. This Pressure-Regulated Ventilator Splitting (PReVentS) Yale University protocol operates under a pressure-control ventilatory mode, and may function optimally when patients are not triggering breaths from the ventilator.This method has been tested thus far only in the laboratory with mock lungs, and has not yet been deployed in animals or in patients. However, given the novelty and potential utility of this approach, we deemed it appropriate to provide this information to the broader critical care community at the present time. In coming days and weeks, we will continue to characterize and refine this approach, using large animal models and proof-of-principle human studies.

First reported in China, the 2019 novel coronavirus has been spreading across the globe. Till 26 March, 2020, 416,686 cases have been diagnosed and 18,589 have died the world over. The coronavirus disease mainly starts with a respiratory illness and about 5-16% require intensive care management for acute respiratory distress syndrome (ARDS) and multi-organ dysfunction. Children account for about 1-2% of the total cases, and 6% of these fall under severe or critical category requiring pediatric intensive care unit (PICU) care. Diagnosis involves a combination of clinical and epidemiological features with laboratory confirmation. Preparedness strategies for managing this pandemic are the need of the hour, and involve setting up cohort ICUs with isolation rooms. Re-allocation of resources in managing this crisis involves careful planning, halting elective surgeries and training of healthcare workers. Strict adherence to infection control like personal protective equipment and disinfection is the key to contain the disease transmission. Although many therapies have been tried in various regions, there is a lack of strong evidence to recommend anti-virals or immunomodulatory drugs.

We aimed to quantify Soft Mist Inhalers (SMI) delivery to spontaneous breathing model and compare with different adapters via endotracheal tube during mechanical ventilation or by manual resuscitation. A tiotropium SMI was used with a commercial in-line adapter and a T-adapter placed between the Y-adapter and the inspiratory limb of the ventilator circuit during mechanical ventilation. The SMI was actuated at the beginning of inspiration and expiration. In separate experiments, a manual resuscitator with T-adapter was attached to endotracheal tube, collecting filter, and a passive test lung. Drug was eluted from collecting filters with salt-based solvent and analyzed using high-performance liquid chromatography. Results showed the percent of SMI label dose inhaled was 3-fold higher with the commercial in-line adapter with actuation during expiration than when synchronized with inspiration. SMI with T-adapter delivery via ventilator was similar to inhalation (1.20%) or exhalation (1.02%), and both had lower delivery dose than with manual resuscitator (2.80%, p = 0.01). The inhaled dose via endotracheal tube was much lower than inhaled dose with spontaneous breathing (22.08%). In conclusion, the inhaled dose with the commercial adapter was higher with SMI actuated during expiration, but still far less than reported spontaneous inhaled dose.

BackgroundAdjusting the fraction of inspired oxygen (FiO2) delivered to preterm infants to keep their oxygen saturation within target range remains challenging. Closed-loop automated FiO2 control increases the time infants spend within the assigned target range. The delay with which FiO2 adjustments at the ventilator result in a change in the inspired gas limits the performance of both manual and automated controls.ObjectiveTo evaluate the equilibration time (Teq) between FiO2 adjustments and changes in FiO2 reaching the patient.MethodsIn vitro determination of the delay in FiO2 adjustments at the ventilator at 5 and 8 L/min of gas flow and two different humidifier/ventilator circuit volumes (840 and 432 mL).ResultsTeq values were 31, 23, 20 and 17 s for the volume–flow combinations 840 mL+5 L/min, 840 mL+8 L/min, 432 mL+5 L/min and 432 mL+8 L/min, respectively.ConclusionThe identified delay seems clinically relevant and should be taken into account during manual and automatic control of FiO2.

Soft mist inhalers (SMIs) generate aerosols with a smaller particle size than pressurized metered-dose inhalers (pMDIs). However, the whole-span particle size distribution (PSD) of SMIs and the optimal delivery method of SMIs during mechanical ventilation have not been fully investigated. This study aimed to measure the PSD of the SMI alone and the SMI coupled to an inhalation aid (eg, a spacer, a valved holding chamber), as well as the delivery efficiency of SMI in different actuation timings and circuit positions during mechanical ventilation. As a suitable comparison, the pMDI was chosen for the same measurement.SMIs (2.5 μg/actuation of tiotropium) were compared with pMDIs (100 μg/actuation of salbutamol). A microorifice uniform deposit impactor was utilized for the particle sizing of drug aerosols generated by inhalers alone, inhalers with a spacer, and inhalers with a valved holding chamber. To optimize the delivery efficiency of both inhalers during mechanical ventilation, the operating parameters included the circuit positions and actuation timings in the ventilator circuit. Particle sizes and inhaled doses were measured with an optical particle sizer and filters used to collect and quantify the drug, respectively.The SMI generated a smaller mass medium aerodynamic diameter (MMAD) than that from the pMDI. The extrafine-particle fraction (EFPF,1 μm) of the SMI was significantly higher than that of the pMDI. With the use of either inhalation aid, the MMAD of both inhalers decreased, and both inhalers with inhalation aid showed significant increases in EFPF. During mechanical ventilation, the optimum way to deliver the SMI and pMDI was at 15 cm from the Y-piece and actuated at the end of expiration and the onset of inspiration, respectively.The SMI with an inhalation aid showed marginal improvement on the PSD. The inhaler type, actuation timing, and position within the circuit also played important roles in delivery efficiency during mechanical ventilation.

Introduction. Exhaled breath condensate (EBC) is a noninvasive method to collect samples from the respiratory tract. Usually, a thermoelectric cooling module is required to collect sufficient EBC volume for analyses. In here, we assessed the feasibility of cytokine and chemokine detection in EBC collected directly from the ventilator circuit without the use of a cooling module: swivel-derived exhaled breath condensate (SEBC). Methods. SEBC was prospectively collected from the swivel adapter and stored at -80°C. The objective of this study was to detect cytokines and chemokines in SEBC with a multiplex immunoassay. Secondary outcomes were to assess the correlation between cytokine and chemokine concentrations in SEBC and mechanical ventilation parameters, systemic inflammation parameters, and hemodynamic parameters. Results. Twenty-nine SEBC samples were obtained from 13 ICU patients. IL-1β, IL-4, IL-8, and IL-17 were detected in more than 90% of SEBC samples, and significant correlations between multiple cytokines and chemokines were found. Several significant correlations were found between cytokines and chemokines in SEBC and mechanical ventilation parameters and serum lactate concentrations. Conclusion. This pilot study showed that it is feasible to detect cytokines and chemokines in SEBC samples obtained without a cooling module. Despite small sample size, correlations were found between cytokines and chemokines in SEBC and mechanical ventilation parameters, as well as serum lactate concentrations. This simple SEBC collection method provides the opportunity to collect EBC samples in large prospective ICU cohorts.

Introduction: Ventilator-associated pneumonia (VAP) is the most frequent and severe infection acquired in the intensive care unit, leading to prolonged mechanical ventilation and excess mortality. This study has been conducted to find out the knowledge regarding prevention of Ventilator Associated Pneumonia (VAP) among nurses.Materials and Methods: A descriptive cross-sectional study was conducted to find out the knowledge regarding prevention of VAP among nurses. Fifty one respondents working in different intensive care areas (ICU, CCU, NICU and PICU) of Universal College of Medical Sciences - Teaching Hospital were selected as the study sample by using census method. Self-administered structured questionnaire was used to collect the data and collected data were analyzed by using descriptive and inferential statistics with SPSS software version 16.Results: The findings of the study revealed that 41.2% and 86.2% of the respondents had knowledge regarding meaning and causative agent of VAP respectively. The mean percentage of risk factors of VAP and VAP bundle were 86.2 and 61.3 respectively. About 37% of the respondents had knowledge regarding oral care with chlorhexidine, 86.3% had knowledge that ventilator circuit should be changed for every new patient and 39.2% of the respondents had knowledge that closed suction system prevents VAP. The findings of the study revealed that 49.1% of the respondents had high knowledge and 7.8% had average knowledge. There was no statistically significant association between respondents' level of knowledge regarding prevention of VAP with respondents' working experience (p=O.493) and qualification (p=O.459).Conclusion: Based on the study findings, it is concluded that almost half of the respondents have high knowledge regarding prevention of VAP. Besides this, respondents have high knowledge regarding VAP (meaning, causative agent, risk factors, principles and complications) and VAP prevention by positioning, airway humidification and suctioning and low knowledge is found on component of VAP bundle, oral care to reduce VAP and ideal cuff pressure of endotracheal tube.Journal of Universal College of Medical SciencesVol. 6, No. 1, 2018, Page: 27-31

Background Oscillatory pressure (ΔP) measurement during high frequency oscillatory ventilation (HFOV) is technically challenging and influenced by all the components of the measurement system. Objectives To evaluate the differences between the ΔP delivered at the inlet of the endotracheal tube and those displayed by commercial neonatal mechanical ventilators and monitoring devices and to characterize how the ventilator circuit and the flowmeter proximal to the patient affect these differences. Methods Six devices were evaluated while ventilating three mechanical analogues representing the newborn respiratory system in different disease states. ΔP measured at different points of the ventilator circuit were compared. Results ΔP accuracy is highly variable and decreases with increasing oscillation frequency and amplitude, independently of the mean airway pressure. At 15 Hz, a ΔP displayed by ventilators of 40 cmH2 O resulted in a ΔP effectively delivered at the tracheal tube ranging from 22 to 49 cmH2 O, depending on the ventilator model, the ventilator circuit, and the patient condition. At these settings, the errors exclusively due to the ventilator circuit and the presence of the flowmeter ranged from 6 to 9 cmH2 O and from 1 to 6 cmH2 O, respectively. Conclusions The ventilator model, the breathing circuit, the flowmeter, and the patient condition severely impacts ΔP measurement accuracy during HFOV, leading to highly variable performances. This prevents the possibility of using the ΔP required to normalize gas exchange as an indicator of patients' condition, complicates comparison of ventilators performances, and adds a significant element of complexity in clinical management of HFOV.

To avoid ventilator-associated lung injury in acute respiratory distress syndrome (ARDS) treatment, respiratory management should be performed at a low tidal volume of 6 to 8 mL/kg and plateau pressure of ≤30 cmH2O. However, such lung-protective ventilation often results in hypercapnia, which is a risk factor for poor outcomes. The purpose of this study was to retrospectively evaluate the effectiveness and safety of the removal of a catheter mount (CM) and using heated humidifiers (HH) instead of a heat-and-moisture exchanger (HME) for reducing the mechanical dead space created by the CM and HME, which may improve hypercapnia in patients with ARDS.This retrospective observational study included adult patients with ARDS, who developed hypercapnia (PaCO2 > 45 mm Hg) during mechanical ventilation, with target tidal volumes between 6 and 8 mL/kg and a plateau pressure of ≤30 cmH2O, and underwent stepwise removal of CM and HME (replaced with HH). The PaCO2 values were measured at 3 points: ventilator circuit with CM and HME (CM + HME) use, with HME (HME), and with HH (HH), and the overall number of accidental extubations was evaluated. Ventilator values (tidal volume, respiratory rate, minutes volume) were evaluated at the same points.A total of 21 patients with mild-to-moderate ARDS who were treated under deep sedation were included. The values of PaCO2 at HME (52.7 ± 7.4 mm Hg, P < .0001) and HH (46.3 ± 6.8 mm Hg, P < .0001) were significantly lower than those at CM + HME (55.9 ± 7.9 mm Hg). Measured ventilator values were similar at CM + HME, HME, and HH. There were no cases of reintubation due to accidental extubation after the removal of CM.The removal of CM and HME reduced PaCO2 values without changing the ventilator settings in deeply sedated patients with mild-to-moderate ARDS on lung-protective ventilation. Caution should be exercised, as the removal of a CM may result in circuit disconnection or accidental extubation. Nevertheless, this intervention may improve hypercapnia and promote lung-protective ventilation.

Background This systematic review aimed to assess inhaled drug delivery in mechanically ventilated patients or in animal models. Whole lung and regional deposition and the impact of the ventilator circuit, the artificial airways and the administration technique for aerosol delivery were analyzed. Methods In vivo studies assessing lung deposition during invasive mechanical ventilation were selected based on a systematic search among four databases. Two investigators independently assessed the eligibility and the risk of bias. Results Twenty-six clinical and ten experimental studies were included. Between 30% and 43% of nominal drug dose was lost to the circuit in ventilated patients. Whole lung deposition of up to 16% and 38% of nominal dose (proportion of drug charged in the device) were reported with nebulizers and metered-dose inhalers, respectively. A penetration index inferior to 1 observed in scintigraphic studies indicated major proximal deposition. However, substantial concentrations of antibiotics were measured in the epithelial lining fluid (887 (406–12,819) μg/mL of amikacin) of infected patients and in sub-pleural specimens (e.g., 197 μg/g of amikacin) dissected from infected piglets, suggesting a significant distal deposition. The administration technique varied among studies and may explain a degree of the variability of deposition that was observed. Conclusions Lung deposition was lower than 20% of nominal dose delivered with nebulizers and mostly occurred in proximal airways. Further studies are needed to link substantial concentrations of antibiotics in infected pulmonary fluids to pulmonary deposition. The administration technique with nebulizers should be improved in ventilated patients in order to ensure an efficient but safe, feasible and reproducible technique. Electronic supplementary material The online version of this article (doi:10.1186/s13054-017-1844-5) contains supplementary material, which is available to authorized users.

BACKGROUND: Aerosolized epoprostenol is an alternative for inhaled nitric oxide in the management of pulmonary arterial hypertension and possibly acute hypoxemia. Our objective was to determine differences in drug deposition based on different nebulizer positions in the ventilator circuit, using a vibrating mesh nebulizer. METHODS: An 8.0-mm inner diameter endotracheal tube (ETT) was connected to a training test lung, compliance of 30 mL/cm H2O, with a collecting filter placed at the ETT-test lung junction. A mechanical ventilator, heated wire circuit, and pass-over humidifier were utilized. A syringe pump continuously instilled a 15,000-ng/mL epoprostenol solution at 30, 50, and 70 ng/kg/min into the vibrating mesh nebulizer at all 4 positions. Tidal volumes (VT) were set at 4, 6, and 8 mL/kg for a 70-kg patient with breathing frequencies of 25, 16, and 12 breaths/min, respectively. Epoprostenol was eluted from the filters (no. = 180) and analyzed with ultraviolet-visible spectrophotometry at 205 nm to estimate drug deposition. RESULTS: Epoprostenol deposition increased significantly (P = .02) as the dosage increased from 30 ng/kg/min (median 4,520.0 ng, interquartile range [IQR] 2,285.0–6,712.2 ng) to 50 ng/kg/min (median 6,065.0 ng, IQR 3,220.0–13,002.5 ng) and 70 ng/kg/min (median 9,890.0 ng, IQR 6,270.0–16,140.0 ng). No significant difference was found between variations in ventilator settings. No difference in deposition was found between the humidifier inlet and outlet, but these positions resulted in greater deposition compared with the inspiratory limb and between the ETT and Y-piece. CONCLUSIONS: The greatest amount of mean epoprostenol deposition resulted with the nebulizer placed at the humidifier inlet or outlet in a ventilator with bias flow.

Background Catheter suction is used to remove tracheal secretions through the endotracheal tube in mechanically ventilated patients, which may be either closed tracheal suction system (CTSS) or open one. In CTSS, the catheter is a part of ventilator circuit with no need to disconnect the ventilator. It seems that the CTSS prevent soiling and spraying of respiratory secretion into the ICU. Objective To compare CTSS system in comparison with an open tracheal suction system in adult patients receiving mechanical ventilation for more than 24 h in terms of VAP incidence, length of stay in the intensive care unit and mortality. Methods We prospectively recruited all mechanically ventilated patients in our general ICU, Dar El Shefa hospital between January 2012 and January 2013. Group A are those with open tracheal suction system (OTSS) and group B with closed tracheal suction system (CTSS), comparing VAP incidence, length of stay in the intensive care unit and mortality between the two groups. Results Group A (OTSS) where the incidence of VAP was 30.13/1000 ventilator days not statistically significant in comparison with patients in group B with CTSS with VAP incidence 17.48/1000 ventilator days. Conclusion There is no difference in the incidence of ventilator associated pneumonia and mortality rates between the two groups. The average length of stay declined in patients with OTSS group.

Background: Ventilator-associated lower respiratory infections (LRIs) and pneumonia (VAP) are important healthcare-associated infections and are among the leading causes of death worldwide. Prevention of these infections are often based on care bundles. We investigated the incidence of VAP+LRI and the preventive efficacy of each component of our ventilator bundle. Methods: Our ventilator bundle includes 6 components that are daily checked by an infection control practitioner. These 6 evidence-based practices were implemented in 3 ICUs from a general tertiary-care private hospital in Belo Horizonte City (Brazil): (1) daily oral care with chlorhexidine; (2) elevate the head of the bed to between 30 and 45; (3) avoid scheduled ventilator circuit change; (4) monitor cuff pressure; (5) use subglottic secretion drainage; and (6) daily sedation interruption and daily assessment of readiness to extubate. VAP and ventilator-LRI definitions were obtained from the CDC NHSN. The impact of adherence rate to items in the ventilator bundle (%) on the incidence rate of VAP+LRI was assessed using linear regression and scatterplot analyses. Results: Between January 2018 and April 2019, 1,888 ventilator days were observed in the 3 ICUs, with 42 VAP and LRI events, an overall incidence rate of 22.2 cases per 1,000 ventilator days. After September 2018, the infection control service started a campaign to increase the ventilator bundle compliance (Fig. 1). Adherence rates to all 6 bundle components increased between January–August 2018 and September 2018–April 2019 from 25% to 55% for daily oral care, from 34% to 79% for elevating the head of the bed, 28% to 86% for avoiding scheduled ventilator circuit change, from 32% to 83% for cuff pressure monitoring, from 32% to 83% for subglottic secretion drainage, and from 33% to 85% for daily sedation interruption. PAV and LRI incidence decreased from 41 to 16 in ICU A, from 22 to 14 in ICU B and from 24 to 18 in ICU C. The impact of each bundle component was identified by linear regression, calculating the percentage of PAV+LRI incidence rate that is explained by bundle item adherence (r2) and correlation coefficient (r): daily sedation interruption (r2 = 48%; r = 0.69; P = .004) (Fig. 2), cuff pressure monitorization (r2 = 0.3721; r = 0.61; P = .016), subglottic secretion drainage (r2 = 36%; r = 0.60; P = .017), avoidance of scheduled ventilator circuit change (r2 = 34%; r = 0.58; P = .023), daily oral care (r2 = 25%; r = 0.50; P = .050), and elevate the head of the bed (r2 = 25%; r = 0.48; P = .067). Conclusions: The impact of each bundle component on preventing PAV+LRI was identified by the study. An educational intervention performed by the infection control service increased the adherence to the ventilator bundle, and the PAV and LRI incidence decreased.Funding: NoneDisclosures: None

The distinct challenges to successful aerosol delivery with jet nebulizers in patients receiving mechanical ventilation are well known.[1][1] Negotiating the ventilator circuit and narrow artificial airway presents a formidable barrier to aerosolized drug particles.[2][2] These obstacles are offset

Background: Spontaneously breathing pediatric patients who are intubated often receive inhaled medications while disconnected from the ventilator circuit. Several medication delivery devices are available. Increased knowledge of drug delivery under this circumstance would allow for optimization of inhaled therapies in that population. Methods: A breathing simulator (VT 200 ml, iT 0.8s, and RR 20/min) was connected to a collection filter, followed by a 5 mm ID cuffed endotracheal tube. Albuterol was delivered via jet nebulizer/t-piece/50 ml tubing extension (6 L/min, 2500 µg/3ml) for 15 minutes. The pMDI (90 µg/puff)/valved holding chamber, and the soft mist inhaler (Combivent Respimat, 100 µg/puff)/adapter, were actuated at the beginning of the inhalation 4 times per test with 4 breaths following each actuation. The pMDI and nebulizer were also tested using the assisted technique (breath support with resuscitation bag). The nebulizer was configured with the unit connected to the endotracheal tube (proximal) or with the extension tubing interposed between them (distal). Tests were done in quadruplicate, and albuterol measured by spectrophotometry (276 nm). Results: (filter dose X±SD in µg) Conclusion: Using standard pediatric dosage, the nebulizer delivered 5 to 7-fold more albuterol than the pMDI or the soft mist inhaler. Placing the nebulizer distal to the endotracheal tube reduced delivery by 56% but was still superior to other devices. The use of the assisted technique did not improve drug delivery.

AIM The aim of this study was to see if a more sophisticated ventilator hyperinflation protocol might result in more sputum clearance compared to manual hyperinflation. BACKGROUND Hyperinflation has been used to mobilize lung secretions in mechanically ventilated patients in the intensive care unit setting for almost 50 years. In the past decade, rather than using a bag external to the ventilator circuit to deliver hyperinflation (known as "bagging" or "manual hyperinflation"), a new technique has evolved using existing ventilator circuitry (known as "ventilator hyperinflation"). One conservative ventilator hyperinflation protocol has demonstrated equivalence with manual hyperinflation in sputum clearance. DESIGN A randomized crossover study. METHOD Patients received manual hyperinflation and ventilator hyperinflation in two randomly ordered treatments on the same day by the same physiotherapist, using a ventilator hyperinflation protocol involving titration of hyperinflation according to airway pressure. RESULTS Between 2013 and 2018, 48 patients were enrolled in the study. Physiotherapy treatment using ventilator hyperinflation yielded significantly more wet weight sputum (median 2.84 g, IQR 1.81, 4.22) than treatment using manual hyperinflation (median 1.5 g, IQR 0.73, 2.31, P

Introduction Invasive mechanical ventilation is a mainstay in neonatal intensive care and co-administration of aerosolised therapeutics is commonly prescribed. Considering their rapid breathing rate, low tidal volumes, small airways and interfaces, neonates present unique challenges for aerosol therapy. The objective of this study was to assess the effect of droplet size on aerosol delivery during simulated ventilation of a neonate. Methods Simulated neonatal mechanical ventilation assessed the lung dose beyond the endotracheal tube (ETT) across two potential nebuliser placement positions within the circuit; at the dry side of the humidifier and between the Wye and ETT. 2 ml of 2 mg/ml salbutamol was nebulised using two vibrating mesh nebulisers (Aerogen Solo, Aerogen, Ireland) of varying droplet size (2.76µm and 4.30µm respectively). A vibrating mesh nebuliser was chosen as it does not add flow or pressure to the ventilator circuit. A neonatal ventilator (VN500, Drager, Germany) (Vt10mL, 60BPM, I:E ratio 1:2) in combination with a 2.5 mm ETT and humidified circuit was used. Lung dose was quantified after capturing aerosol on an absolute filter (RespirGard II 303, Baxter, Ireland) positioned between the ETT and test lung. The mass of drug eluted was determined using UV Spectrophotometry at 276nm. Results were expressed as a percentage of the nominal dose placed in the nebuliser medication cup. Results Discussion Increasing droplet size was associated with a significantly reduced lung dose when the nebuliser was positioned at the dry side of the humidifier (p-value = 0.02). Increasing droplet size was associated with a reduced lung dose when the nebuliser was placed between the Wye and ETT. However, this difference was not found to be statistically significant (p-value = 0.25). In conclusion, these findings demonstrate that droplet size affects aerosol delivery during neonatal mechanical ventilation.

Objectives Ventilator-associated pneumonia (VAP) is a significant cause of prolonged hospital stay and increased mortality in mechanically ventilated children. Studies of the relationship between bacterial colonization of ventilator circuits (VCs) and VAP are lacking. This study aimed to investigate the role of bacterial colonization of VCs in the development of VAP, and to provide evidence for preventing VAP. Methods Mechanically ventilated patients admitted to the paediatric intensive care unit of a teaching hospital in China from October 2018 to November 2019 were enrolled. Specimens were collected from the VC and the patient's lower respiratory tract (LRT) for bacterial culture. Paired bacteria isolated from the VC and the patient's LRT, where colonization of the VC preceded that of the LRT, were evaluated for relatedness using pulsed field gel electrophoresis (PFGE). Results A total of 114 patients were included; the incidence rate of VAP was 28.1% (32/114). A total of 1368 samples were collected from VCs; 16% had positive bacterial culture. There was no significant difference in bacterial colonization of VCs between VAP and non-VAP. In 13 patients, the LRT and VC were concurrently colonized with the same bacteria, where colonization of the VC occurred before colonization of the patient's LRT. PFGE results demonstrated high correlation between bacteria from the LRT and VC in 11 patients. Among 114 mechanically ventilated children, VAP caused by bacteria from the VC occurred in six patients, accounting for 18.8% (6/32) of the overall VAP rate in this study. Discussion Bacterial colonization of the VC is a significant cause of VAP development in mechanically ventilated children. Preventive strategies for early identification and decontamination measures for contaminated VC may play a key role in preventing VAP.

The effects of tiotropium bromide soft mist inhalers (SMIs) in patients with chronic obstructive pulmonary disease (COPD) receiving mechanical ventilation remain unexplored. This study investigated the dynamic effects of a tiotropium SMI on lung mechanics and gas exchange in these patients. We analyzed 11 mechanically ventilated and hemodynamically stable patients with COPD who experienced acute exacerbation and were ready to be weaned from the ventilator. Two puffs of tiotropium (2.5 &mu, g/puff) were administered with a T-adaptor connected to the ventilator circuit. Lung mechanics&mdash, peak inspiratory pressure, plateau pressure, mean airway pressure, maximum respiratory resistance (Rrs), and gas exchange function&mdash, were analyzed. The two-puff tiotropium SMI treatment led to the greatest reduction in Rrs at 6 h, with the Rrs returning to baseline gradually, and significantly improved the PaO2/FiO2 ratio at 24 h. Compared with baseline values, tiotropium SMI had the strongest effect on Rrs between hours 3 and 6 but did not significantly affect hemodynamic parameters. Tiotropium SMI administration in mechanically ventilated patients with COPD achieved the greatest reduction in Rrs at 6 h and significantly improved the PaO2/FiO2 ratio at 24 h. Future studies should investigate whether the bronchodilation effect can be improved with increased dosage or frequency.