POTENTIAL FOR BED SORES DUE TO HIGH PRESSURES : INFLUENCE OF BODY SITES,BODY POSITION,AND MATTRESS DESIGN

SUMMARY Pressures were measured on 10 subjects, supine and sitting, under six anatomical sites prone to bed sores on three different mattresses. Studied were the Clinifloat and Therarest specialist replacement mattresses, and a standard hospital mattress. Mean supine pressures were less than 5 kPa under four sites. Average supine buttock pressure was 2.93 kPa. Occiput and heel pressures were much higher than under other sites, being on average 2.6 and 4.5 times greater respectively than the mean buttock pressure. On sitting up, buttock pressure increased by a factor of 1.7 on average, to a level higher than the accepted capillary closing pressure. Measurements were consistent with mattress design, specific features of which can significantly affect pressure under certain sites.     

MEASUREMENTS OF INTERFACE PRESSURE BETWEEN BODY SITES AND THE SURFACES OF FOUR SPECIALISED AIR MATTRESSES

SUMMARY Four specialised air mattresses had interface pressure measured under six body sites prone to pressure sores in 10 subjects, supine and sitting. The mattresses were the Clinirest (SSI) and FirstStep (KCI) continuous airflow mattress overlays, and Airwave (Pegasus) and Nimbus (Huntleigh) alternating pressure air mattresses. On the mattress overlays, average supine interface pressures were 2.33 kPa (scapula), 4.15 kPa (elbow), 1.94 kPa (sacrum) and 2.79 kPa (buttock), although they were higher at the occiput (7.97 kPa) and heel (11.7 kPa). The alternating pressure air mattresses had an average minimum interface pressure close to zero for three sites, rising to 4.28 kPa under the heel. Average maximum interface pressures were 8.61 kPa (occiput), 5.21 kPa (scapula), 4.90 (elbow), 4.85 kPa (sacrum), 4.61 kPa (buttock) and 13.2 kPa (heel). No accepted scientific method exists for comparing the two types of mattress. Our data suggest a clinical benefit at the occiput and heel (supine) in using an alternating pressure air mattress and a benefit in using a continuous airflow mattress overlay at other sites.     

Effects of absorbent incontinence pads on pressure management mattresses

AIM: The aim of this paper is to report a study to determine the effects of absorbent pads on the pressure-relieving properties of 'standard' and pressure management mattresses. BACKGROUND: Pressure ulcers and incontinence often co-exist. There is a strong association between poor mobility and continence problems and patients using pressure management products are therefore also likely to be using absorbent pads. METHODS: An instrumented articulated anthropometric phantom with simulated soft body 'tissues' in the gluteal and sacral areas was used as the 'subject'. The phantom was raised and lowered on to three mattresses (standard foam, visco-elastic foam and surface-cut foam) in three states: naked, wearing a dry pad (Tena Super, SCA Hygiene AB) and wearing a wet pad. The pressure mapping device Xsensor was used to record the distribution of pressure over the sacral and ischial areas of the phantom. Peak pressure was used as the primary outcome variable and 10 repeats were made on each mattress under each condition. RESULTS: There were substantial and significant differences for all three mattresses in recorded peak pressures between the naked buttocks and the buttocks wearing a dry pad. There were no significant differences between measurements made using the dry vs. wet pad. Peak pressures frequently occurred over areas of pad folds. Additional testing showed that pads that were 'smoothed' by hand had significantly lower peak pressures than 'unsmoothed' pads. CONCLUSIONS: Absorbent pads have a substantial adverse effect on the pressure redistribution properties of mattresses. Pad folds appear to contribute to this effect, which can be ameliorated slightly by smoothing. Absorbent pad manufacturers should consider engineering pads that minimize disruption to pressure management. Further examination of continence and pressure management products is necessary to establish optimum combinations for nursing care.     

Effects of waterbed flotation on indicators of energy expenditure in preterm infants

The purpose of this investigation was to study the effects of nonoscillating waterbeds on three indices of energy expenditure: activity level, heart rate, and behavioral state. Subjects were 22 healthy preterm infants in a neonatal intensive care unit who had reached 31-35 weeks postconceptional age, and whose average weight was 1,482 grams at the onset of the study. Infants were placed on a waterbed for 3 consecutive days and on a standard incubator mattress for 3 consecutive days. Infants served as their own controls on and off the waterbed. Treatment order was randomly counterbalanced. One-hour observations of activity and state occurring in conjunction with heartbeat counts were the repeated measures on each day over both treatment and control conditions. Infants experienced longer durations of quiet sleep, less active awake and fuss states, and fewer state changes and awakenings while on the waterbed. Heart rates were higher after infants were taken off the waterbed. The findings suggest that nonoscillating waterbed flotation is a simple, cost-effective intervention that reduces energy expenditure.     

Special mattresses: effectiveness in preventing decubitus ulcers in chronic neurologic patients

Thirty-two chronic neurologic patients between 19 and 60 years of age were randomly assigned, for a period of three months, to either an alternating air mattress or a silicore mattress to test the preventive qualities of special mattresses in the occurrence of decubitus ulcers. The two groups were comparable on the variables of age, weight, diagnoses, history of disease process, history of being wheelchair bound, history of previous pressures, and mean scores on Norton's scale of risk, which is based on the subject's physical condition, mental alertness, ambulation, mobility and incontinence. No significant differences were observed in the preventive qualities of the two types of special mattresses in terms of the incidence, location, severity, or healing duration of the subjects' decubitus ulcers. Improved studies of common special mattresses are suggested.     

Introducing the pressure support surfaces from Kaymed

The range of support surfaces available is quite varied. It is important that both the purchaser and the users are satisfied with the quality, comfort and the pressure-reducing properties of the mattress. The mattress needs to be versatile, in that it can be used both in a patient's home or in a hospital or nursing home and also on profiling beds. The Kaymed range of mattresses offers increased comfort with low interface pressures for patients up to and including high risk. This product focus examines the Kaymed mattress and looks at the design and results of tests performed on the visco-elastic foam used in the manufacturing of the mattresses.     

Bed design and its effect on chronic low back pain--a limited controlled trial

This study examines the effect of 4 different types of beds on chronic low back pain patients' symptoms and signs. The beds employed were an "orthopedic" hard bed with 720 reinforced coils and a built-in bed board, a softer 500 coil bed, a standard 10 in. thick waterbed, and a hybrid bed of foam and water. Subjectively the majority of patients preferred the hard bed and felt that their back pain improved to a greater extent after 2 weeks on the hard bed as compared to the other beds. The next largest group of patients to show improvement used the waterbed. Limitations in performing the straight leg raising test coincided with the subjective complaints. Significantly improved straight leg raising was observed after use of the hard bed or waterbed in 25% of the patients using those beds. No other objective signs were altered. The 500 coil bed and the hybrid bed proved of no benefit to any patient in this study group. This limited study indicates that hard beds should remain the first choice of patients with chronic low back pain. However, if relief is not obtained for these chronic pain patients, a trial on a waterbed may prove beneficial.     

Effectiveness of mattress overlays in reducing interface pressures during recumbency

This study evaluates the pressure-reduction characteristics of seven mattress overlays. Thirty subjects were evaluated on each support surface to determine the interface pressures that are generated under the most common pressure sore sites. The results of this study indicate that there is great variability in the effectiveness of traditional mattress overlays. The most effective overlays are the Roho and Akros DFD mattresses; whereas 2-inch thick convoluted foam provides no significant protection for the trochanter when the subjects were lying on their sides (lateral position).     

Quantification of pressure relief using interface pressure and tissue perfusion in alternating pressure air mattresses

OBJECTIVE: To examine whether the interface pressure (IP) relief provided by alternating pressure air mattresses (APAMs) is matched with maintenance of tissue perfusion over the points of contact by measuring transcutaneous oxygen and carbon dioxide (tcPO2, tcPCO2). DESIGN: Comparative analysis of 2 APAMs with a 2-parameter continuous time-based method for quantifying pressure relief (PR) and transcutaneous gas measurement for assessing tissue perfusion. SETTING: Rehabilitation research facility in a university hospital. PARTICIPANTS: Eleven able-bodied adult postgraduate student volunteers. MAIN OUTCOME MEASURES: Two full-replacement APAM systems were used. For each mattress the mean maximum and minimum interface pressures; mean peak air pressures in the mattresses; interface pressure durations below 30, 20, and 10 mmHg over a 60-minute period; mean maximum tcPCO2 and minimum tcPO2; and mean area under the tcPO2 and tcPCO2 curves were measured for each subject. RESULTS: IP on the sacrum was held below thresholds of 30, 20, and 10 mmHg longer on a 2-cell, low pressure system than on a 3-cell, high pressure system (p < .001). Integrated over time, tcPO2 levels also indicated that the 2-cell system retained oxygen levels closer to the unloaded baseline than did the 3-cell system (p < .01). tcPCO2 levels did not rise significantly (p > 0.1) compared with the baseline measurement in both mattresses. CONCLUSIONS: PR was sensitive to the design of the APAM, especially its inflation pressure, cycle time, and inflation sequence. If future trials demonstrate that PR values and transcutaneous blood gas measurements correlate significantly with the clinical incidence of pressure sore formation, then this technique may prove useful in assessing the effectiveness of alternating pressure support surfaces.     

Efficacy and cost-effectiveness of the Thermo contour mattress

Use of air mattresses in reduction of pressure sore incidence is an important part of quality patient care. However, there will never be enough air mattresses to match the demand as increased education and an increase in the general provision of air mattresses can lead to an unrealistic expectation of obtaining air mattresses when required for patients. This raises the demand for air mattresses and increases costs within hospital trusts. This study examined a way to redress the balance through use of an alternative, cost-effective type of mattress (thermoelastic polymer) in the prevention of pressure sores. Prime consideration was given to the comfort of the patient. The claims of the manufacturers, Barrington Healthcare, that 'patients with Waterlow scores of 23 can be nursed safely on this product' were explored as part of the study. A total of 407 patients took part over a 6-month period. Twenty-four Thermo contour mattresses were loaned to one ward for the study and patients were allocated to the mattress through admission to the experimental ward. Patients were then split into two groups on two wards. Group B were allocated to a Thermo contour mattress and group A were nursed on air mattresses and foam mattresses generally used throughout the trust. Results showed that more patients were comfortable on the Thermo contour mattresses than on all other mattresses. Patients with Waterlow scores under 25 did not develop pressure sores on the Thermo contour mattress. However, the sample of patients with a Waterlow score of between 20 and 25 was small and therefore further research is required.     

Egg crater mattresses: a deposit of methicillin-resistant staphylococcus aureus?

The purpose of this study was to evaluate the microbiological conditions of the egg crater mattress in hospital use to identify the presence of Staphylococcus aureus and its methicillin-resistance phenotype (MRSA). Petrifilm plates were used to collect the microbiological data from the mattresses, in pre-established positions. A total 180 plates were collected in 15 mattresses, 139 (72.2%) of which were positive for Staphylococcus aureus. Of the positive plates, 77 (55.4%) were collected before and 62 (44.6%) after washing the mattresses. There was a significant reduction (p=0.023) in Colony Forming Units (CFU); however, regarding the resistance profile, 8 (53.3%) mattresses with MRSA were identified. Results show the risk of these mattresses acting as a secondary deposit in the infection chain, especially regarding the presence of MRSA.     

Microstructural characteristics of human skin subjected to static versus cyclic pressures.

Pressure ulcers are generally associated with external pressures exceeding internal capillary pressures over bony prominences when the body cannot initiate motor movement to change positions. This investigation evaluated microstructural changes occurring in human skin, in vitro, exposed to static versus cyclic pressures, simulating those recorded for heels of human subjects on various pressure-relief mattresses. Morphological data are reported for tissues exposed to pressure in a bench-scale loading system. Dynamic (cyclic-relief) pressure induced parallel alignments of connective tissue collagen bundles, which themselves became differentially oriented to various degrees perpendicular to the surface of the tissue. Static pressure, with no relief, invariably produced alignment of the collagen bundles of the connective tissue parallel to both one another and to the compressed tissue surface. The precursor to pressure ulcer formation may be microstructural alignment in response to the pressure conditions on tissue.     

A Phantom-Based Method to Assess X-Ray Table Mattress Interface Pressures

BackgroundPressure redistribution performance of x-ray table mattresses can influence the development of pressure ulcers in at-risk populations. Interface pressure analysis, with human participants, is a common method to assess mattresses. This approach has limitations that relate to the lack of standardisation between and within humans.AimThis study aimed to develop and validate an anthropomorphic phantom-based method to assess x-ray table mattress interface pressures as an index of mattress performance.MethodsA three dimensional phantom simulating an adult’s head, pelvis, and heels was printed from x-ray computed tomography image data and attached to a metal frame 175 cm in length. Dry sand was added to the phantom head, pelvis, and heels to represent a range of human weights. Pressure distribution was assessed using XSensor. Phantom validation was achieved by comparing phantom mattress interface pressure characteristics, for five human equivalent weights, against 27 sets of human mattress interface pressure data.ResultsUsing the correlation coefficient R, phantom and human pressure data showed good correlation for the five phantom weights (R values: head = 0.993, pelvis = 0.997, and heels = 0.996).ConclusionA novel method to test x-ray mattresses for interface pressure was developed and validated. The method could have utility in the testing of x-ray mattresses that are in routine use and for new mattress development. Phantom interface pressure data could be provided by manufacturers to help inform procurement decisions when matching mattress characteristics to medical imaging demands and the underlying patient populations.     

Associations between back pain,quality of sleep and quality of mattresses. Double-blind pilot study with hotel guests

BACKGROUND: Associations between back pain, the quality of sleep and the quality of mattress have not yet been investigated systematically. METHODS: At check-out we asked 265 consecutive guests of a trade fair hotel about the subjective quality of sleep in the previous night. Nine rooms had been equipped with new mattresses of three different qualities and prices, but this was kept blind to the hotel staff and the guests. Sleep quality was assessed on an analog scale between 1 (very good) and 5 (very bad) and was analyzed in comparison to the remaining 8-year old mattresses of the hotel, but also with respect to social (e.g. private vs. professional reason for the stay) as well as personal (e.g. previous experience with low back and sleep complaints) characteristics of the guests. RESULTS: The three qualities of the mattresses correlated significantly and positively with the perceived quality of sleep, but the difference to the "old" mattresses was most pronounced for those guests who were staying overnight for professional reasons, or who frequently were suffering from low back pain or sleep disturbances. CONCLUSION: At least for chronic sufferers from back pain and sleep problems, the association between sleep quality and quality of the mattress is significant.     

Reducing pressure ulcer incidence in a long-term setting

Selection of appropriate pressure prevention equipment relies on risk assessment and clinical assessment of the resident/patient. Decisions are then made in combination with manufacturer's recommendations, such as interface pressure testing. However, risk assessments can over-predict and laboratory investigations do not necessarily provide an accurate picture of how individual patients will react to pressures from support services. There are few studies on visco-elastic mattresses and their benefits in reducing pressure ulcer incidence. Therefore, a small study was undertaken to review the efficacy of a pressure-reducing visco-elastic foam mattress. For the benefit of the study, a 20-bedded nursing home was provided with 20 visco-elastic mattresses (Pressurease) and 20 pressure-reducing cushions (Mediform Visco). The study aimed to demonstrate a reduction in pressure ulcer prevalence. The study involved 21 residents over a 6-month period. There was a 58.3% prevalence (of Stirling grade 1-2 pressure damage) at trial initiation. The results showed an 85.7% decrease of pressure ulcers within 4 weeks, and an overall decrease of 82.5% over the 6-month period. Comfort levels, scored by residents on a visual analogue scale, demonstrated the Pressurease mattress to be superior to the nursing home standard mattress.     

Preventing pressure ulcers: an evaluation of four operating-table mattresses.

Pressure is a major factor in the development of pressure ulcers. This research focused on assessing the pressure-reducing effects of operating-table mattresses. Five mattresses were tested: a standard operating-table mattress, a foam mattress, a gel mattress, a visco-elastic polyether mattress, and a visco-elastic polyurethane mattress. Four intraoperative postures were evaluated: supine, lateral, fossa, and the Miles-Pauchet position. Interface pressure measurements were performed on 36 healthy volunteers. The foam mattress and the gel mattress seem to have little or no pressure-reducing effect; the polyurethane mattress and the polyether mattress reduce interface pressure significantly better (p < .001); but none of the mattresses reduce pressure sufficiently to prevent the occurrence of pressure ulcers.     

大型压力蒸汽与臭氧消毒床垫的效果比较

目的比较大型压力蒸汽消毒法和臭氧消毒法对医院床垫的消毒效果。方法选择100张床垫,分为两组,各50张,采用压力蒸汽消毒法和臭氧消毒法,对两组床垫的表面细菌和深部载体定量菌的杀灭率进行对照研究。结果蒸汽消毒法对床垫表面细菌的杀灭率为99.92%,臭氧消毒法为94.86%,二者差异无统计学意义(P>0.05);蒸汽消毒法对床垫深部白色念珠菌的杀灭率为100%,高于臭氧法的98.03%(P<0.01)。结论两种消毒方法消毒效果肯定,但蒸汽消毒法穿透性能好、效率高、环保,值得推广。     

Changing pressure-redistributing mattress stocks: costs and outcomes

There remains considerable confusion regarding the selection of appropriate pressure-redistributing support surfaces, although it is accepted that use of low-pressure foam mattresses is likely to reduce the incidence of pressure ulcers compared with standard hospital mattresses. In this study, a 650- hospital replaced its mattress stock with low-pressure foam mattresses with over pounds sterling 100 000 cost savings in the first year after implementation. Incidence and prevalence data were recorded but given the challenges of interpreting apparent trends in the data (due to the lack of robust data collection methodologies and no case-mix adjustment) these data were not included.     

A comparison of mite populations in mattress dust from hospital and from private houses in Cardiff, Wales.

Fifty mattress dust samples from private houses were examined--all were mite infested. Dermatophagoides pteronyssinus occurred in all samples and accounted for 81% of all mites. In thirty-two paired samples the total mite population of bedroom floor dust was only 10% of that found in the corresponding mattress dust. D. pteronyssinus was the dominant species in both and the population of this mite amounted to 7-5% of that found in the mattress dust. An analysis of mattress dust from 100 hospital beds showed that ninety-four mattresses were mite free; the other six contained only seven mites, all D. pteronyssinus. It is suggested that frequent changing and washing of bed linen and brushing and cleaning of mattresses were the main factors in preventing mite infestation in the Cardiff hospitals.     

Laboratory performance of alternating pressure air mattresses component and sequelae

The performance of three different alternating pressure air mattresses with different geometries of air cell were compared (Nimbus 3, Heritage, Tamora Plus), using simple performance indices based on pressure mapping. The aim of this study was to examine the effect on performance of elevating the backrest and thigh section of the bed into sitting position. Ten healthy volunteers of various sizes were pressure-mapped over the full pressure cycle on three alternating pressure air mattresseses with differing cell geometries. This was then repeated with the beds profiled to a sitting position. Performance of the alternating pressure air mattresses in terms of their ability to redistribute pressure dynamically was assessed in the different positions. The different alternating pressure air mattresses performed similarly with the bed in the lying flat position, but smaller cells appeared to be more effective in the sitting position. A conclusion was made that cell geometry may have an effect on the ability of the mattress to achieve alternating behaviour in the sitting position.