Custom-Fit Three-Dimensional-Printed BiPAP Mask to Improve Compliance in Patients Requiring Long-Term Noninvasive Ventilatory Support

Mask interfaces and devices for home noninvasive ventilation in children

Home noninvasive ventilation (NIV), including continuous (CPAP) and bilevel (BPAP) positive airway pressure, is increasingly used in children worldwide. In this narrative review, we present a comprehensive summary of the equipment available for home NIV in pediatrics, excluding neonates. NIV may be challenging in young children, as the majority of the equipment has been developed for adults. Regarding the interfaces, only a few masks have been specifically developed for young children in recent years, while older children may benefit from a large variety of interfaces. Even though much progress has been made, skin injuries are still present, and need to be managed rapidly. Several studies addressed the management of the side effects, but recent studies are lacking regarding orofacial anomalies. No recent study reported the available interfaces for young children and the strategies for an optimal mask fit. Regarding the devices, an adapted NIV device to pediatrics that allows an adequate patient's breathing detection should guarantee optimal ventilatory efficiency and monitoring of NIV. A close follow-up and regular monitoring should be mandatory to rule out the potential issues, optimize NIV therapy and ascertain the efficacy of NIV. However, studies are lacking to guide the choice of devices in young children and the optimal management of home NIV in pediatrics. We summarized the characteristics of the different interfaces available for young children and the limitations of NIV devices. We finally addressed potential areas for future research on long-term home NIV in children.

Method for evaluating the fit of custom-fit Continuous Positive Airway Pressure masks using finite element analysis

Continuous Positive Airway Pressure (CPAP) is a common therapy used to treat breathing disorders such as obstructive sleep apnea. In previous work, we designed a custom-fit CPAP mask to address comfort and leakage issues patients often experience. This paper presents a method to create a finite element (FE) model to evaluate the fit of the custom-fit mask before fabrication. The model includes details such as a skull to represent the variable soft tissue thicknesses on the face, and two strap configurations, original and X. The model was tested on four subjects and results show that the X strap configuration results in a more even stress distribution, measured by standard deviation, on the face compared to the original strap, indicating better fit. The simulations also show gaps in the stress distribution that seem to correspond to areas of leakage based on two initial in vivo tests on two subjects. This simulation method proves to be a valuable tool for custom-fit mask development by allowing us to evaluate designs before fabrication.

Development of personalized non-invasive ventilation masks for critically ill children: a bench study

BACKGROUND

Obtaining a properly fitting non-invasive ventilation (NIV) mask to treat acute respiratory failure is a major challenge, especially in young children and patients with craniofacial abnormalities. Personalization of NIV masks holds promise to improve pediatric NIV efficiency. As current customization methods are relatively time consuming, this study aimed to test the air leak and surface pressure performance of personalized oronasal face masks using 3D printed soft materials. Personalized masks of three different biocompatible materials (silicone and photopolymer resin) were developed and tested on three head models of young children with abnormal facial features during preclinical bench simulation of pediatric NIV. Air leak percentages and facial surface pressures were measured and compared for each mask.

RESULTS

Personalized NIV masks could be successfully produced in under 12 h in a semi-automated 3D production process. During NIV simulation, overall air leak performance and applied surface pressures were acceptable, with leak percentages under 30% and average surface pressure values mostly remaining under normal capillary pressure. There was a small advantage of the masks produced with soft photopolymer resin material.

CONCLUSION

This first, proof-of-concept bench study simulating NIV in children with abnormal facial features, showed that it is possible to obtain biocompatible, personalized oronasal masks with acceptable air leak and facial surface pressure performance using a relatively short, and semi-automated production process. Further research into the clinical value and possibilities for application of personalized NIV masks in critically ill children is needed.

Current treatment strategies in managing side effects associated with domiciliary positive airway pressure (PAP) therapy for patients with sleep disordered breathing: A systematic review and meta-analysis

Sleep disordered breathing is commonly treated with positive airway pressure therapy. Positive airway pressure therapy is delivered via a tight-fitting mask with common side effects including: leak, ineffective treatment, residual sleep disordered breathing, eye irritation, nasal congestion, pressure ulcers and poor concordance with therapy. This systematic review and meta-analysis aimed to identify the effectiveness of current treatment strategies for managing side effects associated with positive airway pressure therapy. Five databases were searched and 10,809 articles were screened, with 36 articles included in the review. Studies investigated: dressings, nasal spray/douche, chin straps, heated humidification and interfaces. No intervention either improved or detrimentally affected: positive airway pressure concordance, Epworth Sleepiness Score, residual apnoea hypopnea index or interface leak. The review was limited by study heterogeneity, particularly for outcome measures. Additionally, patient demographics were not reported, making it difficult to apply the findings to a broad clinical population. This review highlights the paucity of evidence supporting treatment strategies to manage side effects of positive airway pressure therapy.

3D printing in palliative medicine: systematic review

Background

Three-dimensional printing (3DP) enables the production of highly customised, cost-efficient devices in a relatively short time, which can be particularly valuable to clinicians treating patients with palliative care intent who are in need of timely and effective solutions in the management of their patients’ specific needs, including the relief of distressing symptoms.

Method

Four online databases were searched for articles published by December 2020 that described studies using 3DP in palliative care. The fields of application, and the relevant clinical and technological data were extracted and analysed.

Results

Thirty studies were reviewed, describing 36 medical devices, including anatomical models, endoluminal stents, navigation guides, obturators, epitheses, endoprostheses and others. Two-thirds of the studies were published after the year 2017. The main reason for using 3DP was the difficulty of producing customised devices with traditional methods. Eleven papers described proof-of-concept studies that did not involve human testing. For those devices that were tested on patients, favourable clinical outcomes were reported in general, and treatment with the use of 3DP was deemed superior to conventional clinical approaches. The most commonly employed 3DP technologies were fused filament fabrication with acrylonitrile butadiene styrene and stereolithography or material jetting with various types of photopolymer resin.

Conclusion

Recently, there has been a considerable increase in the application of 3DP to produce medical devices and bespoke solutions in the delivery of treatments with palliative care intent. 3DP was found successful in overcoming difficulties with conventional approaches and in treating medical conditions requiring highly customised solutions.

Development of Personalized Non-Invasive Ventilation Interfaces for Neonatal and Pediatric Application Using Additive Manufacturing

The objective of this study was to present a methodology and manufacturing workflow for non-invasive ventilation interfaces (NIV) for neonates and small infants. It aimed to procure a fast and feasible solution for personalized NIV produced in-house with the aim of improving fit and comfort for the patient. Three-dimensional scans were obtained by means of an intraoral (Trios 3) and a facial scanner (3dMd Flex System). Fusion 360 3D-modelling software was employed to automatize the design of the masks and their respective casting molds. These molds were additively manufactured by stereolithography (SLA) and fused filament fabrication (FFF) technologies. Silicone was poured into the molds to produce the medical device. In this way, patient individualized oronasal and nasal masks were produced. An automated design workflow and use of additive manufacturing enabled a fast and feasible procedure. Despite the cost for individualization likely being higher than for standard masks, a user-friendly workflow for in-house manufacturing of these medical appliances proved to have potential for improving NIV in neonates and infants, as well as increasing comfort.

Reduced Air Leakage During Non-Invasive Ventilation Using a Simple Anesthetic Mask With 3D-Printed Adaptor in an Anthropometric Based Pediatric Head-Lung Model

Non-invasive ventilation (NIV) is increasingly used in the support of acute respiratory failure in critically ill children admitted to the pediatric intensive care unit (PICU). One of the major challenges in pediatric NIV is finding an optimal fitting mask that limits air leakage, in particular for young children and those with specific facial features. Here, we describe the development of a pediatric head-lung model, based on 3D anthropometric data, to simulate pediatric NIV in a 1-year-old child, which can serve as a tool to investigate the effectiveness of NIV masks. Using this model, the primary aim of this study was to determine the extent of air leakage during NIV with our recently described simple anesthetic mask with a 3D-printed quick-release adaptor, as compared with a commercially available pediatric NIV mask. The simple anesthetic mask provided a better seal resulting in lower air leakage at various positive pressure levels as compared with the commercial mask. These data further support the use of the simple anesthetic mask as a reasonable alternative during pediatric NIV in the acute setting. Moreover, the pediatric head-lung model provides a promising tool to study the applicability and effectiveness of customized pediatric NIV masks in the future.

Toward Mass Customization Through Additive Manufacturing: An Automated Design Pipeline for Respiratory Protective Equipment Validated Against 205 Faces

Respiratory protective equipment (RPE) is traditionally designed through anthropometric sizing to enable mass production. However, this can lead to long-standing problems of low-compliance, severe skin trauma, and higher fit test failure rates among certain demographic groups, particularly females and non-white ethnic groups. Additive manufacturing could be a viable solution to produce custom-fitted RPE, but the manual design process is time-consuming, cost-prohibitive and unscalable for mass customization. This paper proposes an automated design pipeline which generates the computer-aided design models of custom-fit RPE from unprocessed three-dimensional (3D) facial scans. The pipeline successfully processed 197 of 205 facial scans with <2 min/scan. The average and maximum geometric error of the mask were 0.62 mm and 2.03 mm, respectively. No statistically significant differences in mask fit were found between male and female, Asian and White, White and Others, Healthy and Overweight, Overweight and Obese, Middle age, and Senior groups.

Establishing a point-of-care additive manufacturing workflow for clinical use

Additive manufacturing, or 3-Dimensional (3-D) Printing, is built with technology that utilizes layering techniques to build 3-D structures. Today, its use in medicine includes tissue and organ engineering, creation of prosthetics, the manufacturing of anatomical models for preoperative planning, education with high-fidelity simulations, and the production of surgical guides. Traditionally, these 3-D prints have been manufactured by commercial vendors. However, there are various limitations in the adaptability of these vendors to program-specific needs. Therefore, the implementation of a point-of-care in-house 3-D modeling and printing workflow that allows for customization of 3-D model production is desired. In this manuscript, we detail the process of additive manufacturing within the scope of medicine, focusing on the individual components to create a centralized in-house point-of-care manufacturing workflow. Finally, we highlight a myriad of clinical examples to demonstrate the impact that additive manufacturing brings to the field of medicine.

Design and Fabrication of Custom-Fit BiPAP and CPAP Masks Using Three-Dimensional Imaging and Three-Dimensional Printing Techniques

Noninvasive ventilator support such as bi-level positive airway pressure (BiPAP) or continuous positive airway pressure (CPAP) is often used for patients with obstructive sleep apnea or neuromuscular disorders, such as amyotrophic lateral sclerosis (ALS), where respiratory muscles are weakened. Current commercially available masks for BiPAP and CPAP are often cited as being ill-fitting and leaky, leading to poor quality of sleep or reduced usage of therapy. This project seeks to minimize leaks and maximize comfort by developing custom-fit masks. Patient faces are imaged using an in-house camera system to obtain a three-dimensional (3D) facial contour. Custom interfaces are generated based on this contour using interactive computer software. Using 3D printing to enable rapid tooling, these interfaces are produced in a skin-safe silicone and attached to an off-the-shelf (OTS) mask to create a custom mask. The methodology has been initially tested on five healthy subjects who underwent a two-night sleep study, one night with an OTS mask and one night with a custom-fit mask, to evaluate the leakage and comfort of the custom-fit mask compared to the OTS version. Subjects filled out a questionnaire asking them about mask comfort, leakage, and quality of sleep along with open-ended questions. While the custom-fit mask did not reduce the average measured leakage for subjects, subjects reported experiencing less leakage. Overall, results suggest that the custom-fit masks are more comfortable and tolerable than the provided OTS option. Subject feedback will be implemented into future masks that will be used in a clinical study.

Custom Three-Dimensional-Printed CPAP Mask Development, Preliminary Comfort and Fit Evaluation

Obstructive sleep apnea (OSA) is an acute breathing disorder, which causes soft tissue inside the throat to collapse, thus blocking the airways while sleeping. This syndrome is usually treated by the supply of pressurized air delivered by a pump, which is connected to the patient via mouth and/or nose using a mask as an interface. While most of the literature on OSA is focused on the pressure pump and the therapy conditions (pressure, humidity, velocity, etc.) there has been an increased interest in the mask/interface as a key contributing factor to the treatment's effectiveness. Mask-related issues such as skin damage, allergic reactions, or air leaking due to poor fit can deter OSA patients from following this treatment. This study presents a preliminary evaluation of customized mask designs, which are tailored to specific wearer's facial contours. The development process includes the use of three-dimensional scanning/modeling/printing as an integrated workflow. Individual facial features have been digitally acquired and used to generate a custom device, which conforms to predefined facial landmarks of interest, which delimit the mask contour. A trial study was undertaken by recruiting two healthy volunteers for the fit and comfort evaluation of custom mask designs using a randomized fit test with a series of three-dimensional (3D) printed versus commercial standard mask. Results indicate that custom masks exhibit a higher level of comfort compared to conventional continuous positive airway pressure (CPAP) masks particularly on fit, contact pressure and comfort.

Non-invasive Ventilation for Pediatric Hypoxic Acute Respiratory Failure Using a Simple Anesthetic Mask With 3D Printed Adaptor: A Case Report

Non-invasive ventilation (NIV) is increasingly used in the supportive treatment of acute respiratory failure in children in the pediatric intensive care unit (PICU). However, finding an optimal fitting commercial available NIV face mask is one of the major challenges in daily practice, in particular for young children and those with specific facial features. Large air leaks and pressure-related skin injury due to suboptimal fit are important complications associated with NIV failure. Here, we describe a case of a 4-year old boy with cardiofaciocutaneous syndrome and rhinovirus-associated hypoxic acute respiratory failure who was successfully supported with NIV delivered by a simple anesthetic mask connected to a headgear by an in-house developed and 3D printed adaptor. This case is an example of the clinical challenge related to pediatric NIV masks in the PICU, but also shows the potential of alternative NIV interfaces e.g., by using a widely available and relatively cheap simple anesthetic mask. Further personalized strategies (e.g., by using 3D scanning and printing techniques) that optimize NIV mask fitting in children are warranted.

Interfaces, Circuits and Humidifiers

Long-term non-invasive ventilation (LTNIV) has been increasingly used in children to manage chronic respiratory failure and airway obstruction. Interfaces are of paramount importance for non-invasive ventilation (NIV) effectiveness and patient compliance. However, historically, the choice of pediatric mask has been limited by the scarce availability of commercial interfaces. In recent years, an increasing number of different masks have been commercialized for children, allowing to increase the number of patients who could benefit from LTNIV. Factors such as the age of the child, disease, craniofacial conformation, type of ventilator and mode of ventilation, and children's and family's preferences should be taken into account when selecting the appropriate mask. Adverse events such as skin lesions, facial growth impairment, and leaks must be prevented and promptly corrected. Humidification is a controversial issue on NIV, but it may be useful in certain circumstances. Regular cleaning and disinfection of interfaces and equipment must be addressed. During follow-up, educational programs, close supervision, and continuous support to children and families are crucial to the success of LTNIV therapy.