Investigating the effects of strap tension during non-invasive ventilation mask application: a combined biomechanical and biomarker approach

Abstract

Non-invasive ventilation is commonly used for respiratory support. However, in some cases, mask application can cause pressure ulcers to specific features of the face, resulting in pain and reduced quality of life for the individual. This study investigated the effects of mask strap tension on the biomechanical and biomarker responses at the skin interface. Healthy participants (n = 13) were recruited and assigned two different masks in a random order, which were fitted with three strap conditions representing increments of 5 mm to increase tension. Masks were worn for 10 minutes at each tension followed by a 10-minute refractory period. Assessment at the device–skin interface included measurements of pressures at the nose and cheeks, temperature and humidity, a selection of inflammatory cytokine concentrations collected from sebum and scores of comfort. The results indicated significantly higher interface pressures at the bridge of the nose compared to the cheeks for both masks (p < 0.05), with nasal interface pressures significantly increasing with elevated strap tension (p < 0.05). One inflammatory cytokine, IL-1α, increased following mask application at the highest tension, with median increases from baselines ranging from 21 to 33%. The other cytokines revealed a less consistent trend with strap tension. The participants reported statistically greater discomfort during elevated strap tension. Temperature and humidity values under the mask were elevated from ambient conditions, although no differences were observed between mask type or strap tension. The bony prominence on the bridge of the nose represented a vulnerable area of skin during respiratory mask application. This study has shown that mask strap tension has a significant effect on the pressure exerted on the nose. This can result in discomfort and an inflammatory response at the skin surface. Further studies are required to investigate respiratory mask application for appropriate individuals with comorbidities.

Dressings cut to shape alleviate facial tissue loads while using an oxygen mask

“…Specifically, the greatest reduction of local contact forces offered by the use of the dressing cuts was at the bridge of the nose. These findings are consistent with previously published research demonstrating that the nose is the most common location for NIV mask‐related PU development . Anatomically, the bridge of the nose is characterised by curved geometry with minimal soft tissue coverage, hence with structural tendency to greater tissue deformations.…”

“…The contact forces developed at the cheeks were considerably lower than those developed at the bridge of the nose or at the chin, being consistent with previously published literature . Moreover, we found that the effect of the dressing cuts on the cheeks was indistinguishable across the experimental study group, possibly because, as stated above, the cheeks contain thicker soft tissue masses and are relatively distant from bony prominences.…”

“…Sensor #5 was placed on the back of the head between the mask straps and the skin, thereby assuring that the mask was fitted to subjects according to manufacturers’ instructions and clinical practice standards. An optimum fit was defined by tensioning the straps of the mask to an extent at which two fingers could slide between the straps and the skin . At this point, the measured force at Sensor #5 was approximately 2.2 N for each subject.…”

“…Specifically, the mask applies compressive and shear forces to the skin at narrow contact sites, which then translate to compound loading states (compression, tension, and shear) including stress concentrations within sub‐dermal tissues . The lack of biomechanical knowledge‐driven guidance for clinicians regarding safe application of NIV masks, as well as the generic mask designs containing traditional stiff polymer materials, which typically do not match the shape and biomechanical properties of the facial tissues, may lead to rapid and serious tissue damage …”

“…[7][8][9][10] The lack of biomechanical knowledge-driven guidance for clinicians regarding safe application of NIV masks, as well as the generic mask designs containing traditional stiff polymer materials, which typically do not match the shape and biomechanical properties of the facial tissues, may lead to rapid and serious tissue damage. 4,[11][12][13][14][15][16] Recent studies have shown that approximately one-third of all hospital-acquired pressure ulcers (PUs) are associated with the use of medical devices, which led to the use of the term medical device-related PUs (MDRPUs) in national and international PU classifications. 8,17 The incidence of NIVrelated PUs, in particular, depends on the duration of mask usage and varies within the 5% to 50% range for 2 to 4 hours of continuous use.…”