The 2019 novel coronavirus disease (COVID-19) pandemic has brought the effects of device-related pressure ulcers (DRPU) into sharp focus. With the increased use of personal protective equipment (PPE), including face masks, continuous positive airway pressure (CAPP) masks and other devices, the incidence of DRPUs among health professionals and patients alike has risen starkly. As such, the Journal of Wound Care (JWC) consensus document, Device-related pressure ulcers: SECURE prevention, published in February 2020, is more relevant than ever. To help support patients and frontline health professionals, JWC is republishing the consensus in a digital format, along with a new introductory article outlining the DRPU risks posed by PPE and other medical devices used by patients and health professionals during the pandemic, and how the skin damage can be avoided. The aim is to provide frontline staff with a clear, simple strategy on how to prevent the risk of personal skin damage and/or DRPU during the pandemic, as well as point them in the direction of more indepth guidance on long-term strategies for prevention, for both themselves and patients.

https://www.magonlinelibrary.com/doi/pdf/10.12968/jowc.2020.29.5.245

Update to device-related pressure ulcers: SECURE prevention. COVID-19, face masks and skin damage.

Performance of an advanced combat helmet with different interior cushioning systems in ballistic impact: Experiments and finite element simulations

This article presents a computational and experimental study of contact pressure between six N95 filtering facepiece respirators (FFRs) and five newly developed digital headforms (small, medium, large, long/narrow, and short/wide). Contact interaction is simulated using the finite element method and validated by experiments using a pressure mapping system. The headform model has multiple layers: a skin layer, muscle layer, fatty tissue layer, and bone layer. Each headform is divided into five parts (two parts for the cheeks, one part for the upper forehead, one part for the chin, and one part for the back side of the head). Each respirator model comprises multiple layers and two straps. The simulation process has two stages for each respirator/headform combination. The first stage is to wrap the straps around the back of the headform and pull the respirator away from the face. The second stage is to release the respirator so that the respirator moves toward the face. Strap forces and contact interactions ...

Headform and N95 Filtering Facepiece Respirator Interaction: Contact Pressure Simulation and Validation

Head injury, being one of the main causes of death or permanent disability in everyday life, continues to remain as a major health problem with significant socioeconomic costs. Therefore, there is a need for biomechanical studies of head injury, its mechanisms and its tolerance to external loading. Throughout the decades, finite element head models (FEHMs) have been used to assess the biomechanics of head injury mechanism. Given the fact that some of the internal biomechanical responses of the brain can neither be measured easily nor in-vivo by experimental techniques, FEHM offers a cost-effective alternative to experimental method in estimating the internal biomechanical responses of human head. This review paper aims to provide researchers in this field with some background information about head injury. A thorough literature review has been done to summarize the essential details in terms of modeling, material properties and boundary conditions of various FEHMs. The outline of this review is divided into two main sections. The first section consists of definitions, epidemiology, mechanism and classifications of head injury as well as some basic anatomy of human head. Beginning with the history of FEHMs and their revolution in geometry and complexity, the second section would be focusing on the various mechanical aspects of the FEHMs. Various boundary conditions and validations used by the FEHMs are also included in the review article. In addition, important findings and head injury criteria from these FEHMs are summarized.

http://www.openscienceonline.com/author/download?paperId=1413&stateId=8000&fileType=3

A Review of Head Injury and Finite Element Head Models

This study measured the facial dimensions of Korean Air Force (KAF) pilots, to design a pilot oxygen mask, and compared them with those of Korean civilians and US Air Force (USAF) personnel. Twenty-two facial dimensions were measured for 278 KAF male pilots (KMP) and 58 KAF female pilots and cadets (KFP) using an anthropometer and a three-dimensional scanner. The KMP face measurements were found to be significantly larger (mean difference,  = 0.7–26.5 mm) and less varied (ratio of SDs = 0.29–0.82) than those of Korean male civilians. The average face length, lip width and nasal root breadth of the KMP were significantly longer (  = 4.7 mm), narrower (  = − 2.4 mm), and wider (  = 5.2 mm), respectively, than those of USAF male personnel. Lastly, the KMP face measurements were significantly larger (  = 1.8–26.1 mm) than those of the KFP. Practitioner Summary: The face measurements of KAF pilots were collected and compared with those of Korean civilians and USAF personnel. The distinct facial features of the...

/pdf/analysis-of-the-facial-measurements-of-korean-air-force-1xm5d66xn2.pdf

Analysis of the facial measurements of Korean Air Force pilots for oxygen mask design.

Ballistic impact is one of the major causes for traumatic brain injury (TBI) and ballistic helmets are designed to provide protection from TBI. In real life, it is impossible to use real human subjects for experiments. Therefore, simulation based-methods are convenient to assess the rear effect to ballistic helmet impact and can provide crucial insights to injury. Rear effect happens when the interior of helmet is deformed and contacts with the human head. This paper proposes a simulation-based method to study the rear effect by using Head Injury Criterion (HIC) when the ballistic helmeted headform is impacted by a bullet with different impact angles and at various impact positions. Commercial software package LS-DYNA is employed to simulate the impact. A high fidelity headform model including detailed skull and brain has been used for the simulation purpose. Helmet and bullet are modeled according to the real shapes. The results show that, with a larger impact angle, the HIC score is smaller and ...

/pdf/simulation-based-assessment-of-rear-effect-to-ballistic-26jzhqb90h.pdf

Simulation-Based Assessment of Rear Effect to Ballistic Helmet Impact

Sensitivity analysis of important parameters affecting contact pressure between a respirator and a headform

Respirator use is an integral part of occupational safety and health practice. The challenge is to design respirators with the best fit and highest comfort level for all workers of diverse anthropometry. This paper presents a method to simulate the interaction between a respirator and a headform, and solutions for the universal design of respirators. Three-dimensional digital headforms and respirators are obtained using reverse engineering techniques. The commercial software, LS-DYNA, is used to model and simulate the interaction between a respirator and headform to determine the key factors that affect respirator fit and comfort. Both the respirator and headform are modeled as shell elements and are deformable. The results show that strap forces play an important role in pressure distribution on the face.

/pdf/simulating-the-interaction-between-a-respirator-and-a-a59py1u2v2.pdf

Simulating the Interaction between a Respirator and a Headform Using LS-DYNA

Human head is the most important but fragile part of human body In order to design the head-gear and study the sophisticated capabilities of human head, the head models have been developing for decades There are two types of human head models: digital headform and finite element model (biomechanical head model) The complexity of head structure makes these attempts very difficult until the invention of the high-speed computers and the modern medical devices like computed tomography (CT) or magnetic resonance imaging (MRI) Head modeling also has widely potential use in the design process of personal head and face protective equipment (PHFPE) Hazards of processes or environment, chemical hazards, radiological hazards, or mechanical irritants are encountered daily for workers Those hazards are capable of causing injury or illness through absorption, inhalation, or physical contact PHFPE includes helmets, masks, eye protection and hearing protection This study attempts to review different kinds of head models and PHFPE, such as respirators, helmets and goggles It mainly focuses on the historical developments

/pdf/human-head-modeling-and-personal-head-protective-equipment-a-3wfl3qt4bo.pdf

Jichang Dai

Papers

Simulation-Based Assessment of Rear Effect to Ballistic Helmet Impact

Sensitivity analysis of important parameters affecting contact pressure between a respirator and a headform

Simulating the Interaction between a Respirator and a Headform Using LS-DYNA

Human Head Modeling and Personal Head Protective Equipment: A Literature Review

Finite Element Analysis for the Interface of a Respirator and the Human Face -A Pilot Study