Effect of thoracic stiffness on chest compression performance - A prospective randomized crossover observational manikin study

Introduction

Human thoracic stiffness varies and may affect the performance during external chest compression (ECC). The Extra Compression Spring Resusci® QCPR Anne manikin is a high-fidelity training model developed for ECC training that can account for varying levels of thoracic stiffness. The aim of this study was to use this training model to investigate the effects of thoracic stiffness on ECC biomechanics and qualities.

Methods

Fifty-two participants performed standard ECC on the manikin with different thoracic springs to simulate varying levels of thoracic stiffness. The MatScan Pressure Measurement system was used to investigate the ECC pressure and force distribution.

Results

The hard spring group’s performance had a better complete recoil ratio (90.06 ± 24.84% vs. 79.75 ± 32.17% vs. 56.42 ± 40.15%, p < 0.001 at second minute), but was more inferior than the standard and soft spring groups in overall quality, ECC depth (34.17 ± 11.45 mm vs. 41.25 ± 11.42 mm vs. 51.88 ± 7.56, p < 0.001 at second minutes), corrected depth ratio, and corrected rate ratio. The hard spring group had less radial-ulnar peak pressure difference (kgf/cm²) than the other two groups (−0.28 ± 0.38 vs. −0.30 ± 0.43 vs. −0.47 ± 0.34, p = 0.01), demonstrating that more symmetrical pressure was applied in the hard spring group. The soft spring group had better ECC depth, corrected depth ratio, corrected rate ratio, and overall quality, but its performance in complete recoil was inferior, and unbalanced pressure was more liable to cause injury. Hard springs caused operator fatigue easily.

Conclusion

The thoracic stiffness greatly affected the performance of ECC. Our findings provided information for more effective ECC practices and training.

Objective measurement of sitting - Application in children with cerebral palsy

BACKGROUND

Children with cerebral palsy (CP) and a severe motor impairment, have limited ability to perform volitional movements due to spasticity, involuntary postures and movements and reduced ability to maintain antigravity head and trunk control. A stable sitting position is a prerequisite for participation in daily life, but there is a lack of objective measurement methods for this population.

RESEARCH QUESTION

Is it feasible to measure a stable sitting position with pressure mapping and 2D motion analysis, and can it detect differences to a) a reference group, b) between subgroups of CP and c) before and after treatment with intrathecal baclofen (ITB)?

METHODS

Pressure mapping, and a 2D motion analysis system, were used to capture movements of centre of pressure (CoP), and movements of head, hand and leg, sitting on a bench for 90 s. Twenty-two children with dyskinetic or bilateral spastic CP, GMFCS III-V, mean age 9.0, and 30 children with typical development (TD) mean age 10.7, were recruited between 2010 and 2019. Seventeen children were treated with ITB. Parents were interviewed regarding aspect of sitting. Non-parametric methods were used for statistical analysis.

RESULTS

Differences in CoP and kinematics were detected with more movements in children with CP compared to children with TD (p < 0.001). There were more movements in children with dyskinetic CP compared to children with bilateral spastic CP as captured with the pressure mapping system (CoP distance p = .005 and Anterio-Posterior sway p = .014). After treatment with ITB, involuntary movements had decreased (CoP p = 0.006-0.035, kinematics p = 0.002-0.020). Parents reported improvement in sitting. The two measurement systems showed consistent results (rho 0.500-0.771, p = <0.001-0.049).

SIGNIFICANCE

It was feasible to objectively measure sitting position in children with a moderate-to-severe motor impairment with differences to a reference group and after an intervention. CoP and head movements were the variables that were easiest to capture.

Chair design for older immobile people: Comparison of pressure mapping and manual handling outcomes

The number of older adults unable to transfer or ambulate independently is increasing. High support chairs enable people experiencing loss of mobility to be mobile, but current chair designs are associated with global functional loss and pressure ulcers. This pilot study compared the functionality of a traditional design high support chair to a new design of motorised high support chair: 1) a motion laboratory study compared joint angles and pressure at the hip, knee, ankle, elbow and spine when pushing each chair, and 2) a pressure mapping study compared the interface pressure when older people with limited mobility used the chairs. Significant reduction in joint angles for the person pushing the chair (degree difference range -3.6 to 14.2) and decreased seated pressure (w/kg difference range -0.2 to 2.1) for the seated user were identified for the motorised chair. Longitudinal investigations are required to determine if the significant differences identified in this pilot study result in less manual handling injuries and pressure areas.

Pressure distributions on the chair seat and backrest correlate with handwriting outcomes of school children

BACKGROUND

Postures while sitting are believed to have an important influence on the process of writing and quality of handwriting, but data in this field are sparse.

OBJECTIVES

The current study was undertaken to investigate correlations between 'ordinary' children's handwriting skills and their posture and stability while sitting.

METHODS

Twenty-nine children with typical development (age 9.2±0.8 years) underwent the Hebrew Handwriting Evaluation, while the pressure distributions on their seats and backrests were recorded using a pressure mapping system.

RESULTS

There was an increase in the odds of erasing and overwriting letters in dictation tasks when body displacements of the buttocks increased [Odds Ratio (OR) = 1.01, 95% CI 1.000-1.02, p = 0.050]. Children who did not lean on the backrest were more likely to have legible handwriting in copying tasks (OR = 0.136, 95% CI 0.026-0.723, p = 0.019).

CONCLUSIONS

The awareness and involvement of health practitioners in sitting postures of children at school might promote activities such as writing. Further investigation of movement patterns while writing and of the correlations of these patterns with handwriting outcomes is recommended. More research regarding adjustments at the school environment for children with developmental disorders is also warranted.

A Hydrogel Meniscal Replacement: Knee Joint Pressure and Distribution in an Ovine Model Compared to Native Tissue

Pressure distribution of the native ovine knee meniscus was compared to a medial meniscectomy and three treatment conditions including a suture reattachment of the native tissue, an allograft, and a novel thermoplastic elastomer hydrogel (TPE) construct. The objective of this study was to assess the efficacy of a novel TPE hydrogel construct at restoring joint pressure and distribution. Limbs were loaded in uniaxial compression at 45°, 60°, and 75° flexion and from 0 to 181 kg. The medial meniscectomy decreased contact area by approximately 50% and doubled the mean and maximum pressure reading for the medial hemijoint. No treatment condition tested within this study was able to fully restore medial joint contact area and pressures to the native condition. A decrease in lateral contact area and increase in pressures with the meniscectomy was also seen; and to some degree, all reattachment and replacement conditions including the novel TPE hydrogel replacement helped to restore lateral pressures. Although the TPE construct did not perform as well as hoped in the medial compartment, it performed as well as, if not better, than the other reattachment and replacement options in the lateral. Further work is necessary to determine the best anchoring and attachment methods.

Comparing the interface pressure redistribution after applying three different types of cushions: differences according to cushion type

[Purpose] The purpose of this study was to compare the interface pressure redistribution when sitting after applying three different types of cushions and on a firm surface in individuals in their 20s and those older than 60 years old. [Subjects and Methods] Healthy 100 elderly (60 years and older) subjects and 111 college students participated in this study. Interface pressure redistribution while sitting on a firm surface or honeycomb, air, and memory foam cushions, examined in that order. [Results] For all groups, significant differences were found in the total pressure mean among sitting states. When the hip and thigh interface pressure among sitting states were compared within each group, significant differences were found in the mean right hip pressure, mean left hip pressure, peak right hip pressure, peak left hip pressure, right hip pressure ratio, and left hip pressure ratio. [Conclusion] Our data indicated that the type of cushion should be considered and fit for individuals when recommending appropriate interface pressure redistribution cushions.

Comparing the interface pressure redistribution of three different types of cushions: differences according to age groups and cushion preferences

[Purpose] The purpose of this study was to analyze the change in interface pressure redistribution of three different types of cushions sat on by individuals in their 20s and older than 60 years old. [Subjects and Methods] One hundred and eleven college students and 100 persons than 60 years old were recruited. Sitting pressure redistribution was measured while subjects sat without cushions or on honeycomb, air, and memory foam cushions in that order. Subsequently, the cushion preference was measured. After obtaining all measurements, the mean total pressure and each quadrant's mean and peak pressure were analyzed. [Results] The mean hip and the peak pressures were low in the group of females aged 60 years or older, and the highest in the group of males in their 20s. The hip pressure ratio was low in the groups of females in their 20s and 60 years or older, whereas the thigh pressure ratio was high in the same groups. The analysis of cushion preference showed that the groups of males (42.0%) and females (40.0%) in their 20s mostly preferred air cushion. The men (55.1%) and women (50.0%) aged 20 years or older selected honeycomb and air cushions as the first and third preferred cushions with a high response rate. [Conclusion] Our results indicate that gender and age should be considered when recommending appropriate pressure redistribution cushions.

Objectively quantifying walking ability in degenerative spinal disorder patients using sensor equipped smart shoes

Lumbar spinal stenosis (LSS) is a condition associated with the degeneration of spinal disks in the lower back. A significant majority of the elderly population experiences LSS, and the number is expected to grow. The primary objective of medical treatment for LSS patients has focused on improving functional outcomes (e.g., walking ability) and thus, an accurate, objective, and inexpensive method to evaluate patients' functional levels is in great need. This paper aims to quantify the functional level of LSS patients by analyzing their clinical information and their walking ability from a 10 m self-paced walking test using a pair of sensorized shoes. Machine learning algorithms were used to estimate the Oswestry Disability Index, a clinically well-established functional outcome, from a total of 29 LSS patients. The estimated ODI scores showed a significant correlation to the reported ODI scores with a Pearson correlation coefficient (r) of 0.81 and p<3.5×10(-11). It was further shown that the data extracted from the sensorized shoes contribute most to the reported estimation results, and that the contribution of the clinical information was minimal. This study enables new research and clinical opportunities for monitoring the functional level of LSS patients in hospital and ambulatory settings.

Reduced pressure for fewer pressure ulcers: can real-time feedback of interface pressure optimise repositioning in bed?

The aim of this study was to (i) describe registered nurses' and assistant nurses' repositioning skills with regard to their existing attitudes to and theoretical knowledge of pressure ulcer (PU) prevention, and (ii) evaluate if the continuous bedside pressure mapping (CBPM) system provides staff with a pedagogic tool to optimise repositioning. A quantitative study was performed using a descriptive, comparative design. Registered nurses (n = 19) and assistant nurses (n = 33) worked in pairs, and were instructed to place two volunteers (aged over 70 years) in the best pressure-reducing position (lateral and supine), first without viewing the CBPM monitor and then again after feedback. In total, 240 positionings were conducted. The results show that for the same person with the same available pressure-reducing equipment, the peak pressure varied considerably between nursing pairs. Reducing pressure in the lateral position appeared to be the most challenging. Peak pressures were significantly reduced, based on visual feedback from the CBPM monitor. The number of preventive interventions also increased, as well as patients' comfort. For the nurses as a group, the knowledge score was 59·7% and the attitude score was 88·8%. Real-time visual feedback of pressure points appears to provide another dimension to complement decision making with respect to PU prevention.