Fill volume, humidification and heat effects on aerosol delivery and fugitive emissions during noninvasive ventilation

Aerosol therapy in adult critically ill patients: a consensus statement regarding aerosol administration strategies during various modes of respiratory support

BACKGROUND

Clinical practice of aerosol delivery in conjunction with respiratory support devices for critically ill adult patients remains a topic of controversy due to the complexity of the clinical scenarios and limited clinical evidence.

OBJECTIVES

To reach a consensus for guiding the clinical practice of aerosol delivery in patients receiving respiratory support (invasive and noninvasive) and identifying areas for future research.

METHODS

A modified Delphi method was adopted to achieve a consensus on technical aspects of aerosol delivery for adult critically ill patients receiving various forms of respiratory support, including mechanical ventilation, noninvasive ventilation, and high-flow nasal cannula. A thorough search and review of the literature were conducted, and 17 international participants with considerable research involvement and publications on aerosol therapy, comprised a multi-professional panel that evaluated the evidence, reviewed, revised, and voted on recommendations to establish this consensus.

RESULTS

We present a comprehensive document with 20 statements, reviewing the evidence, efficacy, and safety of delivering inhaled agents to adults needing respiratory support, and providing guidance for healthcare workers. Most recommendations were based on in-vitro or experimental studies (low-level evidence), emphasizing the need for randomized clinical trials. The panel reached a consensus after 3 rounds anonymous questionnaires and 2 online meetings.

CONCLUSIONS

We offer a multinational expert consensus that provides guidance on the optimal aerosol delivery techniques for patients receiving respiratory support in various real-world clinical scenarios.

Minimizing Aerosol Leakage from Facemasks in the COVID-19 Pandemic

Background: Aerosol therapies with vented facemasks are considered a risk for nosocomial transmission of viruses such as severe acute respiratory syndrome coronavirus 2. The transmission risk can be decreased by minimizing aerosol leakage and filtering the exhaled air. Objective: In this study, we determined which closed facemask designs show the least leakage. Methods: Smoke leakage was quantified during in- and exhalation in a closed system with expiration filter for three infant, six child, and six adult facemasks (three times each mask), using age-appropriate anatomical face models and breathing patterns. To assess leakage, smoke release was recorded and cumulative average pixel intensity (cAPI) was calculated. Results: In the adult group, aircushion edges resulted in less leakage than soft edges (cAPI: 407 ± 250 vs. 774 ± 152) (p = 0.004). The Intersurgical^® Economy 5 mask (cAPI: 146 ± 87) also released less smoke than the Intersurgical^® Clearlite 5 (cAPI: 748 ± 68) mask with the same size, but different geometry and edge type (p-value <0.05). Moreover, mask size had an effect, as there was a difference between Intersurgical^® Economy 4 (cAPI: 708 ± 346) and 5, which have the same geometry but a different size (p-value <0.05). Finally, repositioning masks increased the standard deviations. Mask leakage was not dependent on breathing patterns within the child group. Conclusions: Mask leakage can be minimized by using a closed system with a well-fitting mask that is appropriately positioned. To decrease leakage, and therewith minimize potential viral transmission, selecting a well-fitting mask with an aircushion edge is to be recommended.

Association between vitamin D deficiency and diabetic foot ulcer wound in diabetic subjects: A meta-analysis

A meta-analysis was performed to evaluate the association between vitamin D deficiency and diabetic foot ulcer wounds in diabetic subjects. A systematic literature search up to March 2022 incorporated 7586 subjects with diabetes mellitus at the beginning of the study; 1565 were using diabetic subjects with foot ulcer wounds, and 6021 were non-ulcerated diabetic subjects. Statistical tools like the dichotomous and contentious method were used within a random or fixed-influence model to establish the odds ratio (OR) and mean difference (MD) with 95% confidence intervals (CIs) to evaluate the influence of vitamin D deficiency in managing diabetic foot ulcer wound. Diabetic subjects with foot ulcer wounds had significantly lower vitamin D levels (MD, -6.48; 95% CI, -10.84 to -2.11, P < .004), higher prevalence of vitamin D deficiency (<50 nmoL/L) (OR, 1.82; 95% CI, 1.32-2.52, P < .001), and higher prevalence of severe vitamin D deficiency (OR, 2.53; 95% CI, 1.65-3.89, P < .001) compared with non-ulcerated diabetic subjects. Diabetic subjects with foot ulcer wounds had significantly lower vitamin D levels, higher prevalence of vitamin D deficiency, and higher prevalence of severe vitamin D deficiency compared with non-ulcerated diabetic subjects. Further studies are required to validate these findings.

Effect of stem cell treatment on burn wounds: A systemic review and a meta-analysis

A meta-analysis was performed to evaluate the effect of stem cells treatment in managing burn wounds. A systematic literature search up to March 2022 incorporated 24 studies reported between 2013 and 2021 including 400 animals with burn wounds at the beginning of the study; 211 were using stem cells treatment, and 189 controlled. Statistical tools like the contentious method were used within a random or fixed-influence model to establish the mean difference (MD) with 95% confidence intervals (CIs) to evaluate the influence of stem cells treatment in managing burn wounds. Stem cells treatment had a significantly higher burn wound healing rate (MD, 15.18; 95% CI, 11.29-19.07, P < .001), higher blood vessel number (MD, 12.28; 95% CI, 10.06-14.51, P < .001), higher vascular endothelial growth factor (MD, 10.24; 95% CI, 7.19-13.29, P < .001), lower interleukin-1 level (MD, -98.48; 95% CI, -155.33 to -41.63, P < .001), and lower tumour necrosis factor α level (MD, -28.71; 95% CI, -46.65 to -10.76, P < .002) compared with control in animals' models with burn wounds. Stem cells treatment had a significantly higher burn wound healing rate, higher blood vessel number, higher vascular endothelial growth factor, lower interleukin-1 level, and lower tumour necrosis factor α level compared with control in animals' models with burn wounds. Further studies are required to validate these findings.

Effect of oxygen flow on aerosol delivery from a vibrating mesh nebulizer with a holding chamber

Background

A holding chamber (HC) was created to work with a vibrating mesh nebulizer (VMN) to boost the total inhalable dose for patients. In addition to the optional supply of supplemental oxygen, it facilitates intermittent and continuous nebulization. Our goal was to see how well a VMN coupled to a HC with a mouthpiece or valved facemask performed at varied oxygen flows starting at 0–6 L/min. In this study, we used a breathing simulator to simulate adults' spontaneous breathing patterns with a tidal volume of 500 mL and a 1:1 inhalation–exhalation ratio. For the combination of nebulizer and HC adapter with a valved facemask or mouthpiece, five determinations were made. Salbutamol was recovered and evaluated using high-performance liquid chromatography from the inhalation filter connected to the breathing simulator, the nebulizer reservoir chamber, and the HC.

Results

The amount of salbutamol in the nebulizer reservoir chamber and within the HC did not differ significantly when using a mouthpiece or a valved facemask. However, the supplied dose to the inhalation filter was increased until oxygen flow reached 2 and 3 L/min using the mouthpiece and valved facemask as interfaces, respectively. The supplied salbutamol was much higher at this flow than at the other oxygen flows. This was followed by a progressive reduction in the supplied salbutamol until the lowest given dose was reached at 6 L/min oxygen flow, p < 0.005.

Conclusions

The supplied doses of salbutamol to the inhalation filter were variable with the VMN connected to the HC and mouthpiece or valved facemask, with significant improvements until an oxygen flow of 2 L/min with a mouthpiece and 3 L/min with a valved facemask, followed by gradual decreases to lower values at an oxygen flow of 6 L/min. An in vivo investigation is required to further validate the findings.

Effect of serologic malnutrition on postoperative wound infection problems after total joint arthroplasty: A meta-analysis

We performed a meta-analysis to evaluate the effect of serologic malnutrition on postoperative wound infection problems after total joint arthroplasty. A systematic literature search up to April 2022, was performed and 446 501 subjects with total joint arthroplasty at the baseline of the studies; 200 433 of them were confirmed serologic malnutrition, and 246 068 were confirmed normal nutrition. Odds ratio (OR) and 95% confidence intervals (CIs) were calculated to assess the effect of serologic malnutrition on postoperative wound infection problems after total joint arthroplasty using the dichotomous method with a random or fixed-effect model. The serologic malnutrition subjects had a significantly higher wound disruption (OR, 1.97; 95% CI, 1.53-2.53, P < 0.001), higher superficial incisional surgical site infection (OR, 2.89; 95% CI, 1.67-5.01, P < 0.001), higher deep incisional surgical site infection (OR, 3.06; 95% CI, 2.36-3.96, P < 0.001), and higher organ space surgical site infection (OR, 3.15; 95% CI, 2.34-4.24, P < 0.001) in subjects after total joint arthroplasty compared with normal nutrition. The serologic malnutrition subjects had a significantly higher wound disruption, superficial incisional surgical site infection, deep incisional surgical site infection, and organ space surgical site infection in subjects after total joint arthroplasty compared with normal nutrition. The analysis of outcomes should be with caution because of the low number of studies in certain comparisons.

Effect of prophylactic negative pressure treatment for post-surgery groin wounds management in vascular surgery: A meta-analysis

We performed a meta-analysis to evaluate the effect of prophylactic negative pressure treatment for post-surgery groin wounds management in vascular surgery. A systematic literature search up to April 2022 was performed and 1537 total number of groin vascular surgery incisions at the baseline of the studies; 729 of them were using the prophylactic negative pressure treatment, and 808 were using control. Odds ratio (OR) and mean difference (MD) with 95% confidence intervals (CIs) were calculated to assess the effect of prophylactic negative pressure treatment for post-surgery groin wounds management in vascular surgery using the dichotomous, and contentious methods with a random or fixed-effect model. The prophylactic negative pressure treatment subjects had a significantly lower surgical site wound infection (OR, 0.26; 95% CI, 0.16-0.42, P < .001) in subjects after vascular surgery compared with control. However, prophylactic negative pressure treatment did not show any significant difference in revision surgery (OR, 0.73; 95% CI, 0.52-1.00, P = .05), readmission (OR, 0.93; 95% CI, 0.66-1.32, P = .69), mortality in hospital (OR, 0.54; 95% CI, 0.29-1.01, P = .05), and length of hospital stay (MD, -0.24; 95% CI, -0.91-0.44, P = .49) compared with control in subjects after vascular surgery. The prophylactic negative pressure treatment subjects had a significantly lower surgical site wound infection and no significant difference in revision surgery, readmission, mortality in hospital, and length of hospital stay compared with control in subjects after vascular surgery. The analysis of outcomes should be with caution because of the low sample size of 2 out of 10 studies in the meta-analysis and a low number of studies in certain comparisons.

Surgical site wound infection, and other postoperative problems after coronary artery bypass grafting in subjects with chronic obstructive pulmonary disease: A meta-analysis

We performed a meta-analysis to evaluate the effect of chronic obstructive pulmonary disease on surgical site wound infection, and other postoperative problems after coronary artery bypass grafting. A systematic literature search up to April 2022 was performed and 37 444 subjects with coronary artery bypass grafting at the baseline of the studies; 4320 of them were with the chronic obstructive pulmonary disease, and 33 124 were without chronic obstructive pulmonary disease. Odds ratio (OR), and mean difference (MD) with 95% confidence intervals (CIs) were calculated to assess the effect of chronic obstructive pulmonary disease on surgical site wound infection, and other postoperative problems after coronary artery bypass grafting using the dichotomous, and contentious methods with a random or fixed-effect model. The chronic obstructive pulmonary disease subjects had a significantly higher surgical site wound infection (OR, 1.27; 95% CI, 1.01-1.60, P = 0.04), respiratory failure (OR, 1.84; 95% CI, 1.55-2.18, P < 0.001), mortality (OR, 1.61; 95% CI, 1.37-1.89, P < 0.001), pneumonia (OR, 2.30; 95% CI, 1.97-2.68, P < 0.001), pleural effusion (OR, 1.78; 95% CI, 1.12-2.83, P = 0.02), stroke (OR, 1.99; 95% CI, 1.17-3.36, P = 0.01), and length of intensive care unit stay (MD, 0.73; 95% CI, 0.19-1.26, P = 0.008) after coronary artery bypass grafting compared with subjects without chronic obstructive pulmonary disease. However, chronic obstructive pulmonary disease subjects did not show any significant difference in length of hospital stay (MD, 0.83; 95% CI, -0.01 to 1.67, P = 0.05), and pneumothorax (OR, 1.59; 95% CI, 0.98-2.59, P = 0.06) after coronary artery bypass grafting compared with subjects without chronic obstructive pulmonary disease. The chronic obstructive pulmonary disease subjects had a significantly higher surgical site wound infection, respiratory failure, mortality, pneumonia, pleural effusion, stroke, and length of intensive care unit stay, and no significant difference in length of hospital stay, and pneumothorax after coronary artery bypass grafting compared with subjects without chronic obstructive pulmonary disease. The analysis of outcomes should be with caution because of the low sample size of 1 out of 11 studies in the meta-analysis and a low number of studies in certain comparisons.

Effect of platelet-rich plasma vs standard management for the treatment of diabetic foot ulcer wounds: A meta-analysis

We performed a meta-analysis to evaluate the effect of platelet-rich plasma vs standard management for the treatment of diabetic foot ulcer wounds. A systematic literature search up to March 2022 was performed and 1435 subjects with diabetic foot ulcer wounds at the baseline of the studies; 723 of them were treated with platelet-rich plasma, and 712 used control. Odds ratio (OR) with 95% confidence intervals (CIs) was calculated to assess the effect of platelet-rich plasma vs standard management for the treatment of diabetic foot ulcer wounds using the dichotomous method with a random or fixed-effect model. The use of autologous platelet-rich plasma resulted in significantly higher complete-healed diabetic foot ulcer wounds compared with control (OR, 1.95; 95% CI, 1.49-2.56, P < 0.001). The use of allogeneic platelet-rich plasma resulted in significantly higher complete-healed diabetic foot ulcer wounds compared with control (OR, 6.19; 95% CI, 2.32-16.56, P < 0.001). The use of autologous and allogeneic platelet-rich plasma resulted in significantly higher complete-healed diabetic foot ulcer wounds compared with control. Though, the analysis of outcomes should be with caution because of the low number of studies in certain comparisons, for example, allogeneic platelet-rich plasma compared with control.

Effectiveness of prophylactic application of negative pressure wound therapy in stopping surgical site wound problems for closed incisions in breast cancer surgery: A meta-analysis

We performed a meta-analysis to evaluate the effect of prophylactic application of negative pressure wound therapy in stopping surgical site wound problems for closed incisions in breast cancer surgery. A systematic literature search up to April 2022 was performed and 2223 women with closed incisions in breast cancer surgery at the baseline of the studies; 964 of them were using the prophylactic application of negative pressure wound therapy, and 1259 were using standard dressings. Odds ratio (OR) with 95% confidence intervals (CIs) were calculated to assess the effect of prophylactic application of negative pressure wound therapy in stopping surgical site wound problems for closed incisions in breast cancer surgery using the dichotomous method with a random or fixed-effect model. The prophylactic application of negative pressure wound therapy women had a significantly lower total wound problems (OR, 0.62; 95% CI, 0.43-0.90, P = .01), lower surgical site wound infection (OR, 0.59; 95% CI, 0.36-0.96, P = .03), lower wound dehiscence (OR, 0.54; 95% CI, 0.39-0.75, P < .001) and lower wound necrosis (OR, 0.44; 95% CI, 0.27-0.71, P < .001), in women with closed incisions in breast cancer surgery compared with standard dressings. However, prophylactic application of negative pressure wound therapy did not show any significant difference in wound seroma (OR, 0.73; 95% CI, 0.32-1.65, P = .45), and hematoma (OR, 0.73; 95% CI, 0.33-1.59, P = .001) compared with standard dressings in women with closed incisions in breast cancer surgery. The prophylactic application of negative pressure wound therapy women had a significantly lower total wound problems, surgical site wound infection, wound dehiscence, and wound necrosis and no significant difference in wound seroma, and hematoma compared with standard dressings in women with closed incisions in breast cancer surgery. The analysis of outcomes should be with caution because of the low sample size of 5 out of 12 studies in the meta-analysis and a low number of studies in certain comparisons.

Effect of prophylactic central neck dissection following total thyroidectomy on surgical site wound infection, hematoma, and haemorrhage in subjects with clinically node-negative papillary thyroid carcinoma: A meta-analysis

We performed a meta-analysis to evaluate the effect of prophylactic central neck dissection following total thyroidectomy on surgical site wound infection, hematoma, and haemorrhage in subjects with clinically node-negative papillary thyroid carcinoma. A systematic literature search up to April 2022 was performed and 3517 subjects with clinically node-negative papillary thyroid carcinoma at the baseline of the studies; 1503 of them were treated with prophylactic central neck dissection following total thyroidectomy, and 2014 were using total thyroidectomy. Odds ratio (OR) with 95% confidence intervals (CIs) were calculated to assess the effect of prophylactic central neck dissection following total thyroidectomy on surgical site wound infection, hematoma, and haemorrhage in subjects with clinically node-negative papillary thyroid carcinoma using the dichotomous method with a random or fixed-effect model. The prophylactic central neck dissection following total thyroidectomy subjects had a significantly lower surgical site wound infection (OR, 0.40; 95% CI, 0.20-0.78, P = .007) in subjects with clinically node-negative papillary thyroid carcinoma compared with total thyroidectomy. However, prophylactic central neck dissection following total thyroidectomy did not show any significant difference in hematoma (OR, 0.08; 95% CI, 0.43-2.71, P = .87), and haemorrhage (OR, 0.72; 95% CI, 0.26-1.97, P = .52) compared with total thyroidectomy in subjects with clinically node-negative papillary thyroid carcinoma. The prophylactic central neck dissection following total thyroidectomy subjects had a significantly higher surgical site wound infection, and no significant difference in hematoma, and haemorrhage compared with total thyroidectomy in subjects with clinically node-negative papillary thyroid carcinoma. The analysis of outcomes should be with caution because of the low number of studies in certain comparisons.

Effect of body mass index on surgical site wound infection, mortality, and postoperative hospital stay in subjects undergoing possibly curative surgery for colorectal cancer: A meta-analysis

We performed a meta-analysis to evaluate the effect of body mass index on surgical site wound infection, mortality, and postoperative hospital stay in subjects undergoing possibly curative surgery for colorectal cancer. A systematic literature search up to March 2022 was performed and 2247 subjects with possibly curative surgery for colorectal cancer at the baseline of the studies; 2889 of them were obese, and 9358 were non-obese. Odds ratio (OR) and mean difference (MD) with 95% confidence intervals (CIs) were calculated to assess the effect of body mass index on surgical site wound infection, mortality, and postoperative hospital stay in subjects undergoing possibly curative surgery for colorectal cancer using the dichotomous or contentious methods with a random or fixed-effect model. The obese subjects had a significantly higher surgical site wound infection after colorectal surgery (OR, 1.87; 95% CI, 1.62-2.15, P < .001), and higher mortality (OR, 1.58; 95% CI, 1.07-2.32, P = .02) in subjects with possibly curative surgery for colorectal cancer compared with non-obese. However, obese did not show any significant difference in postoperative hospital stay (MD, 0.81; 95% CI, -0.030 to 1.92, P = .15) compared with non-obese in subjects with possibly curative surgery for colorectal cancer. The obese subjects had a significantly higher surgical site wound infection after colorectal surgery, higher mortality, and no significant difference in postoperative hospital stay compared with non-obese in subjects with possibly curative surgery for colorectal cancer. The analysis of outcomes should be with caution because of the low number of studies in certain comparisons.

A systemic review and a meta-analysis on the influences of closed incisions in orthopaedic trauma surgery by negative pressure wound treatment compared with conventional dressings

We performed a meta-analysis to evaluate the influences of closed incisions in orthopaedic trauma surgery (OTS) by negative pressure wound treatment (NPWT) compared with conventional dressings. A systematic literature search up to March 2022 was done and 14 studies included 3935 subjects with OTS at the start of the study; 2023 of them used NPWT and 1912 were conventional dressings. They were reporting relationships between the influences of closed incisions in OTS by NPWT compared with conventional dressings. We calculated the odds ratio (OR) with 95% confidence intervals (CIs) to assess the influences of closed incisions in OTS by NPWT compared with conventional dressings using the dichotomous methods with a random or fixed-effect model. NPWT had significantly lower deep surgical site infections (SSIs) (OR, 0.65; 95% CI, 0.48-0.87, P = .004), superficial SSIs (OR, 0.34; 95% CI, 0.19-0.61, P < .001), and wound dehiscence (OR, 0.41; 95% CI, 0.21-0.80, P = .009) compared with conventional dressings in subjects with closed incisions in OTS. NPWT showed a beneficial effect on deep SSIs, superficial SSIs, and wound dehiscence compared with conventional dressings in subjects with closed incisions in OTS. Further studies are required to validate these findings.

Aerosol delivery of inhalation devices with different add-on connections to invasively ventilated COPD subjects: An in-vivo study

Aerosol delivery to mechanically ventilated patients requires add-on connections to place the inhalation device within the ventilation circuit. The study aimed to evaluate the performance of Combihaler in dual limb invasive mechanical ventilation (IMV). A ventilator with a humidified dual limb circuit was adjusted to volume-controlled mode to imitate the adult breathing parameters. 24 (12 females) intubated chronic obstructive pulmonary disease (COPD) subjects had undergone the study. All patients were prescribed inhaled salbutamol dose delivered by either a metered-dose inhaler (pMDI) or vibrating mesh nebulizer (VMN). Each subject received salbutamol in four different inhalation device/connection conditions; pMDI+VMN+Combihaler, VMN+Combihaler, VMN+T-piece, and pMDI+T-piece. They were individually placed in the inspiratory limb at Y-piece. 5mg salbutamol was delivered by VMN with and without 2 pMDI puffs of salbutamol (100 µg), and 500µg was delivered by pMDI+T-piece. After aerosol delivery, two urine samples were collected from the patient; 30 min post-inhalation (USAL0.5) and cumulatively 24 h post-inhalation (USAL24) as indexes of lung deposition and systemic absorption, respectively. For the ex-vivo study, a collecting filter was placed before an endotracheal tube (ETT) to collect the delivered inhalable dose. In-vitro aerodynamic characteristics were also investigated. pMDI+VMN+Combihaler delivered more salbutamol to the lung and the ex-vivo filter than VMN+T-piece (p˂0.05, p≤0.01, respectively). VMN delivered a higher salbutamol amount to the lung, systemically, and the ex-vivo filter than pMDI+T-piece (p˂0.001). pMDI+VMN+Combihaler and VMN+Combihaler delivered aerosols with a less mass median aerodynamic diameter (MMAD) and higher fine particle fraction (FPF) compared to VMN+T-piece (p≤0.01 for MMAD, p˂0.01 for FPF) and pMDI+T-piece (p˂0.01 for both MMAD and FPF). Results of the study showed that pMDI+VMN+ Combihaler delivered more salbutamol than VMN+T-piece in IMV and demonstrate that 5 puffs (500-µg) of salbutamol with pMDI+T-piece has a lower aerosol delivering power at the level of USAL0.5, USAL24, and the ex-vivo inhalable dose than 5 mg nebulized salbutamol by VMNs in IMV.

Impact of different nebulisers' connections on aerosol therapy

BACKGROUND

Aerosol therapy has the advantage of a higher safety because of the local deposition of inhaled medication to the lung; however, the main drawback is the low and variable amount of delivered drug to patients. Hence, this study aimed to investigate the effect of different accessory connections on aerosol delivery from different nebulisers.

METHOD

This study consisted of 3 main models: in vitro, in vivo and ex vivo models. In vitro model, 6 nebulisers (3 Jet (Dolphin (2030 2001), Philips (SideStream) and Tylenol (TL009002)) and 3 vibrating mesh nebulisers (VMNs) (Aerogen Pro, Solo, an Nivo)) were charged with 5 mg/2 mL salbutamol and connected to 2 different connections (T-piece and Circulaire II Hybrid) with an inhalation filter attached to a breathing simulator. Inhaled amounts of drug (inhalation filter) and that remained inside nebuliser were measured. Concerning ex vivo and in vivo models, 24 subjects were involved in the study and they received 5 mg/2 mL salbutamol from 1 Jet nebuliser and 1 VMNs using both connections. Two urine samples were collected post 30 minutes and pooled 24 hours urine collection. For the ex vivo model, inhaled amounts of salbutamol were collected on filters placed between the subjects and the nebuliser.

RESULTS

Inhaled amounts of salbutamol expressed by the amount of drug detected on inhalation filters (for both in vitro and ex vivo) were significantly higher from both Jet and VMNs connected to the Circulaire II Hybrid connection than that released from nebulisers connected to T-piece. VMNs delivered a higher amount compared with jet nebulisers. The amount released from jet nebulizers were variables, unlike VMNs. Regarding in vivo results, amounts of drug detected in 30 minutes urine samples were consistent with in vitro and ex vivo models reflecting higher and significant amounts of drug delivered to the patient's lung for Circulaire II Hybrid connection compared with T-piece regarding both nebulisers.

CONCLUSION

Using a valved chamber with jet and VMNs significantly improved the inhaled amount of the emitted aerosol. VMNs were more effective than jet nebulisers with both connections.

Treating COPD Patients with Inhaled Medications in the Era of COVID-19 and Beyond: Options and Rationales for Patients at Home

COVID-19 has affected millions of patients, caregivers, and clinicians around the world. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spreads via droplets and close contact from person to person, and there has been an increased concern regarding aerosol drug delivery due to the potential aerosolizing of viral particles. To date, little focus has been given to aerosol drug delivery to patients with COVID-19 treated at home to minimize their hospital utilization. Since most hospitals were stressed with multiple admissions and experienced restricted healthcare resources in the era of COVID-19 pandemic, treating patients with COPD at home became essential to minimize their hospital utilization. However, guidance on how to deliver aerosolized medications safely and effectively to this patient population treated at home is still lacking. In this paper, we provide some strategies and rationales for device and interface selection, delivery technique, and infection control for patients with COPD who are being treated at home in the era of COVID-19 and beyond.

COVID-19; current situation and recommended interventions

BACKGROUND

The new coronavirus (SARS-COV-2) that emerged at the end of 2019 was stated in China and infected millions of people around the world, with the highest spread rate amongst humans compared with other coronaviruses. This paper aimed to review and analyse the published studies about COVID-19 diagnosis, prevention, and treatment.

METHOD

The reviewed studies were clinical trials, in-vivo, in-vitro, guidelines, reports from the world health organization (WHO), and the centre for disease control and prevention (CDC) in addition to systemic reviews. All data extracted and analysed to stand on the latest updates and recommendations for fighting this severe attack of COVID-19.

RESULTS

Most important antiviral therapy of COVID-19 clinical trials is still running without clear results, but a few trials have indicated the role of numerous drugs in the treatment of COVID-19. Specific recommendations for aerosol therapy should be followed for the management of COVID-19.

CONCLUSION

Nature of COVID-19 is still not very clear, however, management of the condition is similar to the previous attacks of coronaviruses.

Lung deposition and systemic bioavailability of dose delivered to smoker compared with non-smoker COPD subjects

INTRODUCTION

Inhaled drugs are the most commonly used class of medications for COPD subjects. No studies have been performed to assess the influence of smoking on lung deposition of aerosolized medication, especially for the exacerbated COPD subject. The present study aimed to assess the influence of smoking on the lung deposition of the aerosol delivered to exacerbated COPD subjects.

METHODS

Twenty-four exacerbated COPD subjects using automatic continuous positive airway pressure (Auto-CPAP), 12 smokers (six females) and 12 non-smokers (six females) were recruited in the study. The subjects participated in the study received four salbutamol study doses; 1200 µg (12 puffs 100 µg/puff) of salbutamol emitted from pMDI canister connected to AeroChamber MV spacer; 1200 µg of salbutamol emitted from pMDI canister connected to Combihaler spacer; 1 mL of salbutamol respirable solution (5000 µg/mL) nebulized by Aerogen Solo connected to its T-piece; and 1 mL of salbutamol respirable solution nebulized by Aerogen Solo connected to Combihaler spacer with 2 puffs salbutamol MDI (200 µg salbutamol) before nebulisation. The subjects were randomised to receive the four selected dose-adaptor combination in a sealed envelope design on days 1, 3, 5 and 7. A washout period of 24 hours was provided between each salbutamol dosing. Auto-CPAP was adjusted at non-invasive ventilation mode with the integrated heated humidifier, as a source of humidity. Urine samples were provided by subjects, 30 minutes and cumulatively 24 hours post inhalation, as an index of the relative and systemic bioavailability, respectively, and aliquots were retained for salbutamol analysis using solid-phase extraction and high-performance liquid chromatography (HPLC). On day 2 of the study, a collecting filter was placed between the aerosol generator and the subject's mask so that the subjects would not inhale the salbutamol delivered. The same study doses and/or adapters were delivered to each subject, with filters changed with each dose-adapter combination. Salbutamol entrained on the filter was desorbed to be analysed by the HPLC.

RESULTS

Significantly higher lung deposition (30 minutes urinary salbutamol) was detected with the non-smoker compared with smokers (P < .05). Significantly higher systemic bioavailability (pooled 24-hour urinary salbutamol) for smokers compared with non-smokers was found with Aerogen Solo connected to its T-piece and CombiHaler spacer with pMDI (P < .05) only. Significantly higher amount desorbed from the ex-vivo filter were found from pMDI with both spacers in non-smokers (P < .05) compared with the smokers.

CONCLUSION

The study demonstrated that smoking reduced the lung deposition of inhaled salbutamol delivered by nebulizer or pMDI. However, the smoking effect on cytochrome p450 was observed to increase systemic absorption of the ingested portion of the inhaled dose. The lower lung deposition and possible higher systemic absorption should be taken into consideration while prescribing inhaled medication to COPD smokers especially exacerbated patients that need ventilation. Further studies are needed.

Comparison between traditional and nontraditional add-on devices used with pressurised metered-dose inhalers

Add-on devices that are attached to metered-dose inhalers (MDIs) were introduced to improve aerosol delivery. The objective of this study was to determine the efficacy of drug delivery from an MDI when attached to different add-on devices at different inhalation volumes.

The total emitted dose (TED) of salbutamol was estimated for the MDI alone and the MDI connected to five different add-on devices (Able valved holding chamber, Tips-haler valved holding chamber, Aerochamber plus flow Vu valved holding chamber, Dolphin chamber, and a handmade water bottle spacer), at inhalation flow of 28.3 L·min⁻¹ with flow volume of 1, 2 and 4 L, assuming young child (aged <6 years), old child (>6 years) and adult inhalation volumes, respectively.

The TED% ranged between 84.1% and 87.2% at all inhalation volumes from the MDI alone, which was significantly greater than all MDI add-on device combinations (p<0.05). The TED% delivered to MDI sampling apparatus by a homemade water bottle spacer and Dolphin chamber, as non-antistatic add-on devices, ranged between 30.5% and 35.3%. However, washing these non-antistatic add-on devices with a light detergent before use improved their TED to range between 47.6% and 51.2%. Non-antistatic add-on devices had significantly lower TED (p<0.05) than that delivered by most antistatic add-on devices, which ranged from 51.3% to 71.6%.

This study suggests that antistatic add-on devices delivered much more aerosol than non-antistatic add-on devices. However, it may be advised to still use a non-antistatic add-on device, for the sake of solving the coordination problem, and wash it with light detergent before use to improve TED.

Antistatic add-on devices deliver much more aerosol from MDIs than non-antistatic add-on deviceshttps://bit.ly/3gSE5aR

Practical strategies for a safe and effective delivery of aerosolized medications to patients with COVID-19

The COVID-19, the disease caused by a novel coronavirus and named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread rapidly across the globe. It has caused outbreaks of illness due to person-to-person transmission of the virus mainly via close contacts and droplets produced by an infected person's cough or sneeze. Exhaled droplets from infected patients with COVID-19 can be inhaled into the lungs and leads to respiratory illness such as pneumonia and acute respiratory distress syndrome. Although aerosol therapy is a mainstay procedure used to treat pulmonary diseases at home and healthcare settings, it has a potential for fugitive emissions during therapy due to the generation of aerosols and droplets as a source of respiratory pathogens. Delivering aerosolized medications to patients with COVID-19 can aggravate the spread of the novel coronavirus. This has been a real concern for caregivers and healthcare professionals who are susceptible to unintended inhalation of fugitive emissions during therapy. Due to a scarcity of information in this area of clinical practice, the purpose of this paper is to explain how to deliver aerosolized medications to mild-, sub-intensive, and intensive-care patients with COVID-19 and how to protect staff from exposure to exhaled droplets during aerosol therapy.

Estimated dermal exposure to nebulized pharmaceuticals for a simulated home healthcare worker scenario

The duties of home healthcare workers are extensive. One important task that is frequently performed by home healthcare workers is administration of nebulized medications, which may lead to significant dermal exposure. In this simulation study conducted in an aerosol exposure chamber, we administered a surrogate of nebulizer-delivered medications (dispersed sodium chloride, NaCl) to a patient mannequin. We measured the amount of NaCl deposited on the exposed surface of the home healthcare worker mannequin, which represented the exposed skin of a home healthcare worker. Factors such as distance and position of the home healthcare worker, room airflow rate and patient's inspiratory rate were varied to determine their effects on dermal exposure. There was a 2.78% reduction in dermal deposition for every centimeter the home healthcare worker moved away from the patient. Increasing the room's air exchange rate by one air change per hour increased dermal deposition by about 2.93%, possibly due to a decrease in near field particle settling. For every 10-degrees of arc the home healthcare worker is positioned from the left side of the patient toward the right and thus moving into the ventilation airflow direction, dermal deposition increased by about 4.61%. An increase in the patient's inspiratory rate from 15-30 L/min resulted in an average of 14.06% reduction in dermal deposition for the home healthcare worker, reflecting a relative increase in the aerosol fraction inhaled by the patient. The findings of this study elucidate the interactions among factors that contribute to dermal exposure to aerosolized pharmaceuticals administered by home healthcare workers. The results presented in this paper will help develop recommendations on mitigating the health risks related to dermal exposure of home healthcare workers.

Investigation of Fugitive Aerosols Released into the Environment during High-Flow Therapy

BACKGROUND

Nebulised medical aerosols are designed to deliver drugs to the lungs to aid in the treatment of respiratory diseases. However, an unintended consequence is the potential for fugitive emissions during patient treatment, which may pose a risk factor in both clinical and homecare settings.

METHODS

The current study examined the potential for fugitive emissions, using albuterol sulphate as a tracer aerosol during high-flow therapy. A nasal cannula was connected to a head model or alternatively, a interface was connected to a tracheostomy tube in combination with a simulated adult and paediatric breathing profile. Two aerodynamic particle sizers (APS) recorded time-series aerosol concentrations and size distributions at two different distances relative to the simulated patient.

RESULTS

The results showed that the quantity and characteristics of the fugitive emissions were influenced by the interface type, patient type and supplemental gas-flow rate. There was a trend in the adult scenarios; as the flow rate increased, the fugitive emissions and the mass median aerodynamic diameter (MMAD) of the aerosol both decreased. The fugitive emissions were comparable when using the adult breathing profiles for the nasal cannula and tracheostomy interfaces; however, there was a noticeable distinction between the two interfaces when compared for the paediatric breathing profiles. The highest recorded aerosol concentration was 0.370 ± 0.046 mg m-3 from the tracheostomy interface during simulated paediatric breathing with a gas-flow rate of 20 L/min. The averaged MMAD across all combinations ranged from 1.248 to 1.793 µm by the APS at a distance of 0.8 m away from the patient interface.

CONCLUSIONS

Overall, the results highlight the potential for secondary inhalation of fugitive emissions released during simulated aerosol treatment with concurrent high-flow therapy. The findings will help in developing policy and best practice for risk mitigation from fugitive emissions.

Investigation of the Quantity of Exhaled Aerosols Released into the Environment during Nebulisation

BACKGROUND

Secondary inhalation of medical aerosols is a significant occupational hazard in both clinical and homecare settings. Exposure to fugitive emissions generated during aerosol therapy increases the risk of the unnecessary inhalation of medication, as well as toxic side effects.

METHODS

This study examines fugitively-emitted aerosol emissions when nebulising albuterol sulphate, as a tracer aerosol, using two commercially available nebulisers in combination with an open or valved facemask or using a mouthpiece with and without a filter on the exhalation port. Each combination was connected to a breathing simulator during simulated adult breathing. The inhaled dose and residual mass were quantified using UV spectrophotometry. Time-varying fugitively-emitted aerosol concentrations and size distributions during nebulisation were recorded using aerodynamic particle sizers at two distances relative to the simulated patient. Different aerosol concentrations and size distributions were observed depending on the interface.

RESULTS

Within each nebuliser, the facemask combination had the highest time-averaged fugitively-emitted aerosol concentration, and values up to 0.072 ± 0.001 mg m-3 were recorded. The placement of a filter on the exhalation port of the mouthpiece yielded the lowest recorded concentrations. The mass median aerodynamic diameter of the fugitively-emitted aerosol was recorded as 0.890 ± 0.044 µm, lower the initially generated medical aerosol in the range of 2⁻5 µm.

CONCLUSIONS

The results highlight the potential secondary inhalation of exhaled aerosols from commercially available nebuliser facemask/mouthpiece combinations. The results will aid in developing approaches to inform policy and best practices for risk mitigation from fugitive emissions.

Aerosol Delivery to a Critically Ill Patient: A Big Issue Easily Solved by Developing Guidelines

Nowadays, therapeutic aerosols are commonly delivered to mechanically ventilated patients by nebulizers and pressurized metered dose inhaler attached to an adapter or a spacer. Studies with asthmatics and chronic obstructive pulmonary disease patients have confirmed that aerosol delivery during mechanical ventilation is feasible. They have also reported that the inhaled drugs administered during mechanical ventilation provide greater and faster clinical outcomes than when delivering during spontaneous unassisted breathing. Researchers studied factors that would affect aerosol delivery during mechanical ventilation. Even with the tremendous amount of publications in this area, there have still been no recommendations or guidelines released to help respiratory therapists in their decision as to when to deliver aerosol to ventilated patients. Mostly, respiratory therapists read the literature and decide accordingly what to do and which device to use for their patients. This puts the patients at risk of receiving a sub-therapeutic or toxic dose of the inhaled aerosol. Some studies raise an alarm of physician decision upon reading any released publication related to aerosol delivery in mechanical ventilation without a trusted recommendation and guidelines. This increases the need for the development of recommendations and guidelines, by a trusted board or society, for aerosol delivery to such critically ill patients. To summarize, inhaled drugs administered to critically ill patients is of benefit compared to taking the patient off the ventilator and delivering during spontaneous unassisted breathing. However, dependable guidelines are needed to optimize aerosol delivery.

Modeling and optimization of nebulizers' performance in non-invasive ventilation using different fill volumes: Comparative study between vibrating mesh and jet nebulizers

BACKGROUNDS

Substituting nebulisers by another, especially in non-invasive ventilation (NIV), involves many process-variables, e.g. nebulizer-type and fill-volume of respirable-dose, which might affect patient optimum-therapy. The aim of the present work was to use neural-networks and genetic-algorithms to develop performance-models for two different nebulizers.

METHODS

In-vitro, ex-vivo and in-vivo models were developed using input-variables including nebulizer-type [jet nebulizer (JN) and vibrating mesh nebulizer (VMN)] fill-volumes of respirable dose placed in the nebulization chamber with an output-variable e.g. average amount reaching NIV patient. Produced models were tested and validated to ensure effective predictivity and validity in further optimization of nebulization process.

RESULTS

Data-mining produced models showed excellent training, testing and validation correlation-coefficients. VMN showed high nebulization efficacy than JN. JN was affected more by increasing the fill-volume. The optimization process and contour-lines obtained for in-vivo model showed increase in pulmonary-bioavailability and systemic-absorption with VMN and 2 mL fill-volumes.

CONCLUSIONS

Modeling of aerosol-delivery by JN and VMN using different fill-volumes in NIV circuit was successful in demonstrating the effect of different variable on dose-delivery to NIV patient. Artificial neural networks model showed that VMN increased pulmonary-bioavailability and systemic-absorption compared to JN. VMN was less affected by fill-volume change compared to JN which should be diluted to increase delivery.

Lung deposition and systemic bioavailability of different aerosol devices with and without humidification in mechanically ventilated patients

BACKGROUND

During mechanical ventilation medical aerosol delivery has been reported to be upto two fold greater with dry inhaled gas than with heated humidity. Urine levels at 0.5 h post dose (URSAL0.5%) has been confirmed as an index of lung deposition and 24 h (URSAL24%) as index of systemic absorption. Our aim was to determine the effect of humidification and aerosol device type on drug delivery to ventilated patients using urine levels.

METHODS

In a randomized crossover design, 36 (18female) mechanically ventilated patients were assigned to one of three groups. Groups 1 and 2 received 5000 μg salbutamol using vibrating mesh (VM) and jet nebulizers (JN), respectively, while group 3 received 1600 μg (16 puffs) of salbutamol via metered dose inhaler with AeroChamber Vent (MDI-AV). All devices were placed in the inspiratory limb of ventilator downstream from the humidifier. Each subject received aerosol with and without humidity at >24 h intervals with >12 h washout periods between salbutamol doses. Patients voided urine 15 min before each study dose and urine samples were collected at 0.5 h post dosing and pooled for the next 24 h.

RESULTS

The MDI-AV and VM resulted in a higher percentage of urinary salbutamol levels compared to the JN (p < 0.05). Urine levels were similar between humidity and dry conditions.

CONCLUSIONS

Our findings suggest that in-vitro reports overestimate the impact of dry vs. heated humidified conditions on the delivery of aerosol during invasive mechanical ventilation.

Inhaled salbutamol dose delivered by jet nebulizer, vibrating mesh nebulizer and metered dose inhaler with spacer during invasive mechanical ventilation

BACKGROUND

Patient receiving invasive mechanical ventilation (IMV) may benefit from medical aerosol, but guidance on dosing with different aerosol devices is limited to in-vitro studies. The study was designed to compare aerosol delivery with five different types of aerosol generators during IMV.

METHOD

In randomized design, 60 (30 female) mechanically ventilated chronic obstructive pulmonary disease (COPD) patients were assigned to one of 5 groups. Groups 1-4 received 5000 μg salbutamol using Aerogen Pro (PRO), Aerogen Solo (SOLO), NIVO vibrating mesh and jet nebulizers (JN), respectively, while group 5 received 800 μg (8 puffs) of salbutamol via metered dose inhaler with AeroChamber-MV (MDI-AC). All devices were place in the inspiratory limb of ventilator downstream from humidifier which was switched off while delivery. Patients received the inhaled dose on day 1 and provided urine 30 post dosing. They also recived the same inhaled dose with a filter before the endotracheal tube on day 2. Amount of salbutamol excreted in urine 30 min post inhalation and the amount deposited on the filter from all the COPD patients were determined as indeces of pulmonary deposition and systemic absorption, respectively.

RESULTS

No significant difference was found between the 3 vibrating mesh nebulizers (VMNs). The in-vivo and ex-vivo testing showed that all the VMNs resulted in better aerosol delivery compared to JN (p < 0.01). However, MDI-AC resulted in better aerosol delivery to VMNs but must be accompanied with careful attention and proper delivery of MDI-AC doses by healthcare provider.

CONCLUSIONS

VMNs can be exchanged with each other, with no dose adjustment. However, dose adjustment is a must when replacing VMNs by JN or MDI-AC. This similarity and difference between the 5 aerosol delivery methods suggest that for IMV patients, aerosol delivery methods should be chosen or substituted with care.