Pressure injuries in mechanically ventilated COVID-19 patients utilising different prone positioning techniques - A prospective observational study.

OBJECTIVES: To compare the incidence and distribution of pressure injuries (PIs) with two approaches to prone positioning for mechanically ventilated COVID-19 patients, and to determine the prevalence of these PIs on intensive care unit (ICU) and hospital discharge. DESIGN: A prospective observational study. SETTING: Adult patients admitted to a quaternary ICU with COVID-19-associated acute lung injury, between September 2021 and February 2022. MAIN OUTCOME MEASURES: Incidence and anatomical distribution of PIs during ICU stay for "Face Down" and "Swimmers Position" as well as on ICU and hospital discharge. RESULTS: We investigated 206 prone episodes in 63 patients. In the Face Down group, 26 of 34 patients (76 %) developed at least one PI, compared to 10 of 22 patients (45 %) in the Swimmers Position group (p = 0.02). Compared to the Swimmers Position group, the Face Down group developed more pressure injuries per patient (median 1 [1, 3] vs 0 [0, 2], p = 0.04) and had more facial PIs (p = 0.002). In a multivariate logistic regression model, patients were more likely to have at least one PI with Face Down position (OR 4.67, 95 % CI 1.28, 17.04, p = 0.02) and greater number of prone episodes (OR 1.75, 95 % CI 1.12, 2.74, p = 0.01). Over 80 % of all PIs were either stage 1 or stage 2. By ICU discharge, 29 % had healed and by hospital discharge, 73 % of all PIs had healed. CONCLUSION: Swimmers Position had a significantly lower incidence of PIs compared to the Face Down approach. One-quarter of PIs had healed by time of ICU discharge and three-quarters by time of hospital discharge. IMPLICATIONS FOR CLINICAL PRACTICE: There are differences in incidence of PIs related to prone positioning approaches. This study validates and helps better inform current prone position guidelines recommending the use of Swimmers Position. The low prevalence of PIs at hospital discharge is reassuring.

Magnitude and time to peak oxygenation effect of prone positioning in ventilated adults with COVID-19 related acute hypoxemic respiratory failure.

BACKGROUND: Prone positioning may improve oxygenation in acute hypoxemic respiratory failure and was widely adopted in COVID-19 patients. However, the magnitude and timing of its peak oxygenation effect remain uncertain with the optimum dosage unknown. Therefore, we aimed to investigate the magnitude of the peak effect of prone positioning on the PaO2 :FiO2 ratio during prone and secondly, the time to peak oxygenation. METHODS: Multi-centre, observational study of invasively ventilated adults with acute hypoxemic respiratory failure secondary to COVID-19 treated with prone positioning. Baseline characteristics, prone positioning and patient outcome data were collected. All arterial blood gas (ABG) data during supine, prone and after return to supine position were analysed. The magnitude of peak PaO2 :FiO2 ratio effect and time to peak PaO2 :FIO2 ratio effect was measured. RESULTS: We studied 220 patients (mean age 54 years) and 548 prone episodes. Prone positioning was applied for a mean (±SD) 3 (±2) times and 16 (±3) hours per episode. Pre-proning PaO2 :FIO2 ratio was 137 (±49) for all prone episodes. During the first episode. the mean PaO2 :FIO2 ratio increased from 125 to a peak of 196 (p < .001). Peak effect was achieved during the first episode, after 9 (±5) hours in prone position and maintained until return to supine position. CONCLUSIONS: In ventilated adults with COVID-19 acute hypoxemic respiratory failure, peak PaO2 :FIO2 ratio effect occurred during the first prone positioning episode and after 9 h. Subsequent episodes also improved oxygenation but with diminished effect on PaO2 :FIO2 ratio. This information can help guide the number and duration of prone positioning episodes.

Neuromuscular blockade and oxygenation changes during prone positioning in COVID-19.

PURPOSE: Neuromuscular blockers (NMBs) are often used during prone positioning to facilitate mechanical ventilation in COVID-19 related ARDS. However, their impact on oxygenation is uncertain. METHODS: Multi-centre observational study of invasively ventilated COVID-19 ARDS adults treated with prone positioning. We collected data on baseline characteristics, prone positioning, NMB use and patient outcome. We assessed arterial blood gas data during supine and prone positioning and after return to the supine position. RESULTS: We studied 548 prone episodes in 220 patients (mean age 54 years, 61% male) of whom 164 (75%) received NMBs. Mean PaO2:FiO2 (P/F ratio) during the first prone episode with NMBs reached 208 ± 63 mmHg compared with 161 ± 66 mmHg without NMBs (Δmean = 47 ± 5 mmHg) for an absolute increase from baseline of 76 ± 56 mmHg versus 55 ± 56 mmHg (padj < 0.001). The mean P/F ratio on return to the supine position was 190 ± 63 mmHg in the NMB group versus 141 ± 64 mmHg in the non-NMB group for an absolute increase from baseline of 59 ± 58 mmHg versus 34 ± 56 mmHg (padj < 0.001). CONCLUSION: During prone positioning, NMB is associated with increased oxygenation compared to non-NMB therapy, with a sustained effect on return to the supine position. These findings may help guide the use of NMB during prone positioning in COVID-19 ARDS.

Responsiveness of Critically Ill Adults With Multimorbidity to Rehabilitation Interventions: A Patient-Level Meta-Analysis Using Individual Pooled Data From Four Randomized Trials.

OBJECTIVE: To explore if patient characteristics (pre-existing comorbidity, age, sex, and illness severity) modify the effect of physical rehabilitation (intervention vs control) for the coprimary outcomes health-related quality of life (HRQoL) and objective physical performance using pooled individual patient data from randomized controlled trials (RCTs). DATA SOURCES: Data of individual patients from four critical care physical rehabilitation RCTs. STUDY SELECTION: Eligible trials were identified from a published systematic review. DATA EXTRACTION: Data sharing agreements were executed permitting transfer of anonymized data of individual patients from four trials to form one large, combined dataset. The pooled trial data were analyzed with linear mixed models fitted with fixed effects for treatment group, time, and trial. DATA SYNTHESIS: Four trials contributed data resulting in a combined total of 810 patients (intervention n = 403, control n = 407). After receiving trial rehabilitation interventions, patients with two or more comorbidities had HRQoL scores that were significantly higher and exceeded the minimal important difference at 3 and 6 months compared with the similarly comorbid control group (based on the Physical Component Summary score (Wald test p = 0.041). Patients with one or no comorbidities who received intervention had no HRQoL outcome differences at 3 and 6 months when compared with similarly comorbid control patients. No patient characteristic modified the physical performance outcome in patients who received physical rehabilitation. CONCLUSIONS: The identification of a target group with two or more comorbidities who derived benefits from the trial interventions is an important finding and provides direction for future investigations into the effect of rehabilitation. The multimorbid post-ICU population may be a select population for future prospective investigations into the effect of physical rehabilitation.

The PhLIP team: Feasibility of a physiotherapy-led intensive prone positioning team initiative during the COVID-19 pandemic.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic resulted in a surge of patients with refractory hypoxaemic respiratory failure being admitted to the intensive care unit (ICU). Prone positioning can improve oxygenation but requires a team of skilled personnel to complete safely. Critical care physiotherapists (PTs) are ideally suited to lead proning teams, due to their expertise in moving critically unwell, invasively ventilated patients. OBJECTIVES: The aim of this study was to describe the feasibility of implementing a physiotherapy-led intensive proning (PhLIP) team to support the critical care team during surges. METHODS: This study involves descriptive evaluation of feasibility and implementation of the PhLIP team, a novel model of care, during the Delta wave of the COVID-19 pandemic, through a retrospective, observational audit of PhLIP team activity, ICU clinical activity, and a description of clinical outcomes. RESULTS: Between 17 September and 19 November 2021, 93 patients with COVID-19 were admitted to the ICU. Fifty-one patients (55%) were positioned prone, a median [interquartile range] 2 [2, 5] times, for a mean (±standard deviation) duration of 16 (±2) h, across 161 episodes. Twenty-three PTs were upskilled and deployed to the PhLIP team, adding 2.0 equivalent full time to the daily service. Ninety-four percent of prone episodes (154) were led by the PhLIP PTs with a median 4 [interquartile range: 2, 8] turns per day. Potential airway adverse events occurred on three occasions (1.8%) and included an endotracheal tube leak, displacement, and obstruction. Each incident was promptly managed without prolonged impact on the patient. No manual handling injuries were reported. CONCLUSION: The implementation of a physiotherapy-led proning team was safe and feasible and can release critical care-trained medical and nursing staff to other duties in the ICU.

Measuring Adherence to Long-Term Noninvasive Ventilation.

BACKGROUND: Obtaining benefits from long-term noninvasive ventilation (NIV) relies on achieving adequate adherence to treatment. Reported adherence to NIV is variable and could be influenced by high-volume users and attrition of nonusers and those who die. This observational study aimed to describe patterns of use and adherence rates in new unselected users of NIV. METHODS: All adults (> 18 y old) commencing long-term NIV were consecutively enrolled and followed for 6 months. Ventilator data were manually downloaded from devices and usage (minutes per day) was collected. Subjects were categorized into adherent users (≥ 4 h/d) and nonadherent users (< 4 h/d). RESULTS: Data were obtained from 86 subjects. Most (65%) had motor neuron disease, and most commenced NIV in an out-patient setting (72%). At one month after NIV implementation, overall average daily use was 302.1 min/d and categorical adherence was 57%. At 6 months or prior to death, overall average daily use increased (388.7 min/d), but categorical adherence was similar (62%). The majority of subjects (84%) remained in the same adherence category from their first month to their sixth month of use or death. Individuals with motor neuron disease demonstrated significantly lower rates of adherence compared to the rest of the cohort at 1 month (48% vs 73%, P = .03). In those who died within the study period (n = 19, all with motor neuron disease), this difference persisted to death (42% at death vs 73% at 6 months, P = .032). CONCLUSIONS: Average daily usage may conceal true prevalence of adherence or nonadherence to NIV within a population. Reporting both average daily use data and categorical adherence rates (using a threshold of 4 h/d) may improve transparency of reported outcomes from clinical trials and identifies a therapeutic target for home mechanical ventilation services for quality improvement.

Recumbent cycling to improve outcomes in people with hip fracture: a feasibility randomized trial.

BACKGROUND: Early mobilization after surgery is a key recommendation for people with hip fracture, however this is achieved by only 50% of people. Recumbent bike riding has been used in other populations with limited mobility and has potential to allow early exercise in people post hip fracture. The primary aim of this pilot trial was to demonstrate the feasibility of a trial protocol designed to determine the effect of early post-operative cycling in bed on outcomes in people with hip fracture. METHODS: Single-blinded, multi-site randomized controlled pilot trial. Fifty-one people with hip fracture were recruited within 4 days of surgery from two sites in Victoria. Participants were randomly allocated to receive either usual care (n = 25) or usual care plus active cycling in bed (n = 26). The cycling intervention was delivered on weekdays until the participant could walk 15 m with assistance of one person. The primary outcomes were trial feasibility and safety. Clinical outcomes, including mobility (Modified Iowa Level of Assistance Scale) and delirium were measured at day seven post-operatively and at hospital discharge by an assessor blinded to group. Additional outcomes at discharge included gait speed, cognition and quality of life. RESULTS: The intervention was safe, feasible and acceptable to patients and staff. Delivery of the intervention was ceased on (median) day 9.5 (IQR 7, 12); 73% of scheduled sessions were delivered; (median) 4 sessions (IQR 2.0, 5.5) were delivered per participant with (median) 9 min 34 s (IQR 04:39, 17:34) of active cycling per session. The trial protocol was feasible, however at day seven 75% of participants had not met the criterion (able to walk 15 m with assistance of one person) to cease the cycling intervention.. CONCLUSION: In bed cycling is feasible post-operatively following hip fracture, however seven days post-operatively is too early to evaluate the impact of the cycling intervention as many participants were still receiving the intervention. A fully powered RCT to explore the effectiveness and cost efficiency of this novel intervention is warranted. TRIAL REGISTRATION: The trial was prospectively registered (25/09/2017) with the Australian New Zealand Clinical Trials Registry ACTR N12617001345370 .

Prevalence of sleep-disordered breathing in people with tetraplegia-a systematic review and meta-analysis.

STUDY DESIGN: Systematic review with meta-analysis. OBJECTIVES: To determine the prevalence of sleep-disordered breathing (SDB) in people with tetraplegia and to identify the characteristics associated with SDB. METHODS: A systematic literature search using Medline, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL) and grey literature sources was conducted using a combination of spinal cord injury (SCI) and SDB related terms. Articles were restricted to publication dates between 1/1/2000 and 4/9/2020 and with objectively measured SDB with an overnight sleep study. The frequency of SDB stratified by the apnoea hypopnea index (AHI) was extracted and weighted averages, using a random effects model, were calculated with 95% confidence intervals. Sub-group analyses were performed where possible. RESULTS: Twelve articles were included in the review; of these nine were included in meta-analysis (combined sample = 630). Sample sizes and case detection methods varied. Reported SDB prevalence rates ranged from 46 to 97%. The prevalence of at least mild (AHI ≥ 5), moderate (AHI ≥ 15) and severe (AHI ≥ 30) SDB were 83% (95% CI = 73-91), 59% (46-71) and 36% (26-46), respectively. Sub-group analyses found that prevalence increased with age (p < 0.001). There were no statistically significant differences in SDB prevalence by sex (p = 0.06), complete/incomplete SCI (p = 0.06), body mass index (p = 0.07), acute/chronic SCI (p = 0.73) or high/low level of cervical SCI (p = 0.90). CONCLUSION: Our results confirm that SDB is highly prevalent in people with tetraplegia, and prevalence increases with age. The high prevalence suggests that routine screening and subsequent treatment should be considered in both acute and community care.

Optical costs and benefits of disorder in biological photonic crystals.

Photonic structures in ordered, quasi-ordered or disordered forms have evolved across many different animal and plant systems. They can produce complex and often functional optical responses through coherent and incoherent scattering processes, often too, in combination with broadband or narrowband absorbing pigmentation. Interestingly, these systems appear highly tolerant of faults in their photonic structures, with imperfections in their structural order appearing not to impact, discernibly, the systems' optical signatures. The extent to which any such biological system deviates from presenting perfect structural order can dictate the optical properties of that system and, thereby, the optical properties that system delivers. However, the nature and extent of the optical costs and benefits of imperfect order in biological systems demands further elucidation. Here, we identify the extent to which biological photonic systems are tolerant of defects and imperfections. Certainly, it is clear that often significant inherent variations in the photonic structures of these systems, for instance a relatively broad distribution of lattice constants, can consistently produce what appear to be effective visual appearances and optical performances. In this article, we review previously investigated biological photonic systems that present ordered, quasi-ordered or disordered structures. We discuss the form and nature of the optical behaviour of these structures, focusing particularly on the associated optical costs and benefits surrounding the extent to which their structures deviate from what might be considered ideal systems. Then, through detailed analyses of some well-known 1D and 2D structurally coloured systems, we analyse one of the common manifestations of imperfect order, namely, the extent and nature of positional disorder in the systems' spatial distribution of layers and scattering centres. We use these findings to inform optical modelling that presents a quantitative and qualitative description of the optical costs and benefits of such positional disorder among ordered and quasi-ordered 1D and 2D photonic systems. As deviation from perfectly ordered structures invariably limits the performance of technology-oriented synthetic photonic processes, we suggest that the use of bio-inspired fault tolerance principles would add value to applied photonic technologies.

Searching for the Responder, Unpacking the Physical Rehabilitation Needs of Critically Ill Adults: A REVIEW.

Survivors of critical illness can experience persistent deficits in physical function and poor health-related quality of life and utilize significant health care resources. Short-term improvements in these outcomes have been reported following physical rehabilitation. Safety and feasibility of delivering physical rehabilitation are established; however, low physical activity levels are observed throughout the recovery of patients. We provide examples on how physical activity may be increased through interdisciplinary models of service delivery. Recently, however, there has been an emergence of large randomized controlled trials reporting no effect on long-term patient outcomes. In this review, we use a proposed theoretical construct to unpack the findings of 12 randomized controlled trials that delivered physical rehabilitation during the acute hospital stay. We describe the search for the responder according to modifiers of treatment effect for physical function, health-related quality of life, and health care utilization outcomes. In addition, we propose tailoring and timing physical rehabilitation interventions to patient subgroups that may respond differently based on their impairments and perpetuating factors that hinder recovery. We examine in detail the timing, components, and dosage of the trial intervention arms. We also describe facilitators and barriers to physical rehabilitation implementation and factors that are influential in recovery from critical illness. Through this theoretical construct, we anticipate that physical rehabilitation programs can be better tailored to the needs of survivors to deliver appropriate interventions to patients who derive greatest benefit optimally timed in their recovery trajectory.

Response to physical rehabilitation and recovery trajectories following critical illness: individual participant data meta-analysis protocol.

INTRODUCTION: The number of inconclusive physical rehabilitation randomised controlled trials for patients with critical illness is increasing. Evidence suggests critical illness patient subgroups may exist that benefit from targeted physical rehabilitation interventions that could improve their recovery trajectory. We aim to identify critical illness patient subgroups that respond to physical rehabilitation and map recovery trajectories according to physical function and quality of life outcomes. Additionally, the utilisation of healthcare resources will be examined for subgroups identified. METHODS AND ANALYSIS: This is an individual participant data meta-analysis protocol. A systematic literature review was conducted for randomised controlled trials that delivered additional physical rehabilitation for patients with critical illness during their acute hospital stay, assessed chronic disease burden, with a minimum follow-up period of 3 months measuring performance-based physical function and health-related quality of life outcomes. From 2178 records retrieved in the systematic literature review, four eligible trials were identified by two independent reviewers. Principal investigators of eligible trials were invited to contribute their data to this individual participant data meta-analysis. Risk of bias will be assessed (Cochrane risk of bias tool for randomised trials). Participant and trial characteristics, interventions and outcomes data of included studies will be summarised. Meta-analyses will entail a one-stage model, which will account for the heterogeneity across and the clustering between studies. Multiple imputation using chained equations will be used to account for the missing data. ETHICS AND DISSEMINATION: This individual participant data meta-analysis does not require ethical review as anonymised participant data will be used and no new data collected. Additionally, eligible trials were granted approval by institutional review boards or research ethics committees and informed consent was provided for participants. Data sharing agreements are in place permitting contribution of data. The study findings will be disseminated at conferences and through peer-reviewed publications. PROSPERO REGISTRATION NUMBER: CRD42019152526.

Brilliant angle-independent structural colours preserved in weevil scales from the Swiss Pleistocene.

Extant weevils exhibit a remarkable colour palette that ranges from muted monochromatic tones to rainbow-like iridescence, with the most vibrant colours produced by three-dimensional photonic nanostructures housed within cuticular scales. Although the optical properties of these nanostructures are well understood, their evolutionary history is not fully resolved, in part due to a poor knowledge of their fossil record. Here, we report three-dimensional photonic nanostructures preserved in brightly coloured scales of two weevils, belonging to the genus Phyllobius or Polydrusus, from the Pleistocene (16-10 ka) of Switzerland. The scales display vibrant blue, green and yellow hues that resemble those of extant Phyllobius/Polydrusus. Scanning electron microscopy and small-angle X-ray scattering analyses reveal that the subfossil scales possess a single-diamond photonic crystal nanostructure. In extant Phyllobius/Polydrusus, the near-angle-independent blue and green hues function primarily in crypsis. The preservation of far-field, angle-independent structural colours in the Swiss subfossil weevils and their likely function in substrate matching confirm the importance of investigating fossil and subfossil photonic nanostructures to understand the evolutionary origins and diversification of colours and associated behaviours (e.g. crypsis) in insects.

Pneumothorax in neuromuscular disease associated with lung volume recruitment and mechanical insufflation-exsufflation.

A 25-year-old male with Duchenne muscular dystrophy and a 73-year-old male with motor neurone disease both presented with chest pain and increasing dyspnoea following routine mechanical insufflation-exsufflation or lung volume recruitment, on a background of long-term non-invasive ventilation. In each case, chest radiograph revealed a pneumothorax. In both cases the pneumothorax fully resolved following insertion of an intercostal catheter. There was no immediate recurrence and the patients were discharged home and ceased ongoing prophylactic respiratory therapy, although one person had recurrent pneumothoraces subsequently. This rare but serious complication highlights the need for careful risk/benefit analysis by clinicians prescribing these therapies.

Fossil scales illuminate the early evolution of lepidopterans and structural colors.

Lepidopteran scales exhibit remarkably complex ultrastructures, many of which produce structural colors that are the basis for diverse communication strategies. Little is known, however, about the early evolution of lepidopteran scales and their photonic structures. We report scale architectures from Jurassic Lepidoptera from the United Kingdom, Germany, Kazakhstan, and China and from Tarachoptera (a stem group of Amphiesmenoptera) from mid-Cretaceous Burmese amber. The Jurassic lepidopterans exhibit a type 1 bilayer scale vestiture: an upper layer of large fused cover scales and a lower layer of small fused ground scales. This scale arrangement, plus preserved herringbone ornamentation on the cover scale surface, is almost identical to those of some extant Micropterigidae. Critically, the fossil scale ultrastructures have periodicities measuring from 140 to 2000 nm and are therefore capable of scattering visible light, providing the earliest evidence of structural colors in the insect fossil record. Optical modeling confirms that diffraction-related scattering mechanisms dominate the photonic properties of the fossil cover scales, which would have displayed broadband metallic hues as in numerous extant Micropterigidae. The fossil tarachopteran scales exhibit a unique suite of characteristics, including small size, elongate-spatulate shape, ridged ornamentation, and irregular arrangement, providing novel insight into the early evolution of lepidopteran scales. Combined, our results provide the earliest evidence for structural coloration in fossil lepidopterans and support the hypothesis that fused wing scales and the type 1 bilayer covering are groundplan features of the group. Wing scales likely had deep origins in earlier amphiesmenopteran lineages before the appearance of the Lepidoptera.

Optically ambidextrous circularly polarized reflection from the chiral cuticle of the scarab beetle Chrysina resplendens.

The evolution of structural colour mechanisms in biological systems has given rise to many interesting optical effects in animals and plants. The instance of the scarab beetle Chrysina resplendens is particularly distinctive. Its exoskeleton has a bright, golden appearance and reflects both right-handed and left-handed circularly polarized light concurrently. The chiral nanostructure responsible for these properties is a helicoid, in which birefringent dielectric planes are assembled with an incremental rotation. This study correlates details of the beetle's circularly polarized reflectance spectra directly with physical aspects of its structural morphology. Electron micrography is used to identify and measure the physical dimensions of the key constituent components. These include a chiral multilayer configuration comprising two chirped, left-handed helicoids that are separated by a birefringent retarder. A scattering matrix technique is used to simulate the system's optical behaviour in which the roles of each component of the morphological substructure are elucidated by calculation of the fields throughout its depth.

Circularly polarized reflection from the scarab beetle Chalcothea smaragdina: light scattering by a dual photonic structure.

Helicoidal architectures comprising various polysaccharides, such as chitin and cellulose, have been reported in biological systems. In some cases, these architectures exhibit stunning optical properties analogous to ordered cholesteric liquid crystal phases. In this work, we characterize the circularly polarized reflectance and optical scattering from the cuticle of the beetle Chalcothea smaragdina (Coleoptera: Scarabaeidae: Cetoniinae) using optical experiments, simulations and structural analysis. The selective reflection of left-handed circularly polarized light is attributed to a Bouligand-type helicoidal morphology within the beetle's exocuticle. Using electron microscopy to inform electromagnetic simulations of this anisotropic stratified medium, the inextricable connection between the colour appearance of C. smaragdina and the periodicity of its helicoidal rotation is shown. A close agreement between the model and the measured reflectance spectra is obtained. In addition, the elytral surface of C. smaragdina possesses a blazed diffraction grating-like surface structure, which affects the diffuse appearance of the beetle's reflected colour, and therefore potentially enhances crypsis among the dense foliage of its rainforest habitat.