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.     

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.     

The new QUATTRO PLUS mattress replacement system

Since the early development of alternating pressure air mattresses (APAMs) there have been regular alterations in design. These designs have led to improved reliability and performance. This article outlines the changes made by Talley Medical to the QUATTRO PLUS replacement mattress. Improved safety features and design modifications continue the process commenced many years ago which has seen the use of alternating pressure air mattresses become widespread throughout the UK.     

Do different mattresses affect the quality of cardiopulmonary resuscitation?

Objective To determine the effect of different mattresses on cardiopulmonary resuscitation performance and establish whether emergency deflation of an inflatable mattress improves the quality of resuscitation.Design and setting Randomised controlled cross-over trial performed in a general ICUParticipants Critical care staff from a general ICU.Interventions Cardiopulmonary resuscitation on a manikin on the floor or on a bed with a standard foam mattress and inflated and deflated pressure redistributing mattresses. Maximal compression force was measured at different bed heights.Measurements and results Compression depth, duty cycle and rate and percentage correct expired air ventilation were recorded on a manikin. Compression depth was significantly lower on the foam (35.2 mm), inflated (37.2 mm) and deflated mattress (39.1 mm) than the floor (44.2 mm). There were no clinically important differences in duty cycle or compression rate. The quality of ventilation was poor on all surfaces. Maximal compression force declined as bed height increased.Conclusions Resuscitation performance is adversely affected when performed on a bed (irrespective of mattress type) compared to the floor. There were no differences between the inflated and deflated mattresses, although the deflation process did not adversely affect performance. This study does not support the routine deflation of an inflated mattress during resuscitation and questions the potential benefits from using a backboard. The finding that bed height affects maximal compression forces, challenges the recommendation that cardiopulmonary resuscitation be performed with the bed at middle-thigh level and requires further investigation.Dr. Robert Benny was tragically killed in a road accident during the Summer of 2003. Dr. Benny was at the very start of a promising career in surgery. Our thoughts go to his family and friends.G.D.P. and M.T. have received travelling fellowships from Huntleigh Healthcare, and M.T. has previously delivered lectures for Huntleigh Healthcare.     

Development and evaluation of a self-regulating alternating pressure air cushion

Purpose: To investigate the effect of alternating air cells of a newly developed dynamic cushion on interface pressure and tissue oxygenation levels. Method: This cross-over experimental study included 19 healthy volunteers. The dynamic cushion used has an automatic self-regulating alternating pressure air-cell system with 35 small and four large air cells for maintaining posture while seated. This cushion also has 17 bottoming-out detectors that automatically inflate the air cells to release a high interface pressure. To assess the effect of this alternating system, participants sat on the new cushion with an alternating system or static system for 30?min and then performed push-ups. The interface pressure was monitored by pressure-sensitive and conductive ink film sensors and tissue oxygenation levels were monitored by near-infrared spectroscopy. A reactive hyperaemia indicator was calculated using tissue oxygenation levels as an outcome measure. Results: The peak interface pressure was not significantly different between the groups. The reactive hyperaemia indicator was significantly higher in the static group than in the alternating group. Conclusions: An alternating system has beneficial effects on blood oxygenation levels without increasing interface pressure. Therefore, our new cushion is promising for preventing pressure ulcers with patients with limited ability to perform push-ups.

• Implications for Rehabilitation

• A dynamic cushion was developed, which consists of a uniquely-designed air-cell layout, detectors for bottoming out, and an alternating system with multiple air-cell lines.

• The alternating system did not increase interface pressure and it significantly reduced reactive hyperaemia after 30?min of sitting in healthy volunteers.

• This cushion is a new option for individuals who require stable posture but have limitations in performing scheduled push-ups for prevention of pressure ulcers.

     

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.     

Use of Pressurease and Airform mattresses in pressure ulcer care

Large cell dynamic air mattresses are effective in the prevention of pressure ulcers but they still have inherent problems, e.g. the ability of the mattresses to move patients along the mattress through the inflation and deflation of the cells. Also, there have been reports that the inflation and deflation of cells can cause motion sickness. This article reviews two mattresses from Sareo Healthcare Ltd: a static system, Pressurease; and a unique dynamic system, Airform. These two systems offer a cost-effective and clinically effective method of pressure ulcer prevention and therapy.     

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.     

注射晕厥的发生与体位的关系探讨

目的探讨注射和抽血患者晕厥的发生与患者体位的关系,提高患者的注射安全。方法对门诊和急诊肌内注射、静脉注射和静脉抽血患者分为坐位组、半坐位组和平卧位组,分别为坐在靠背木椅上、斜躺在软沙发上、仰卧或侧卧在床位上接受注射或抽血,对每一例注射晕厥患者记录其性别、年龄、使用药物、体位、主要症状体征和血压情况、处理情况和恢复情况。结果坐位组肌内注射、静脉注射和静脉抽血患者注射晕厥的发生率均明显高于半坐卧位组和平卧位组,发生晕厥后2min内血压明显低于半坐卧位组和平卧位组,有显著性差异(P<0.01),晕厥时发生短暂意识丧失率明显高于半坐卧位组和平卧位组,有显著性差异(P<0.05)。结论采取半坐卧位和平卧位注射或抽血可有效地减少患者注射晕厥的发生率和减轻昏厥症状,值得临床推广应用。     

Effects of position and mattress overlay on sacral and heel pressures in a clinical population.

A comparison of pressure reducing properties of alternating air, static air, and water mattress overlays was conducted with 57 patients in a surgical intensive care unit. Sacral and heel pressures in both recumbent and semi-Fowler's positions were tested for each surface using a repeated measures design. Mean pressures for the alternating air mattress were significantly higher than pressures with other surfaces, regardless of position or site. There were significant main effects for position and site, with higher pressures in the semi-Fowler's position and at the sacral site. A significant interaction between surface, site, and position was found. Pressure sores developed in eight patients, but the incidence was not significantly different across groups. A pressure measuring device constructed from available clinical materials proved to be both sensitive and reliable. The findings suggest alternating air overlays should be avoided, and that positioning and periodic position change to reduce sacral pressures for patients requiring prolonged upper body elevation is important.     

The Theracute alternating pressure replacement mattress

The use of alternating pressure mattresses is still acknowledged as an effective adjunct in the prevention and treatment of pressure damage; however, with the plethora of equipment now available, there is an increasing need to provide information that supports the practitioners' decisions ensuring individual patients' clinical needs are met. This article reviews a new addition to the Talley Medical range of alternating pressure mattresses, the Theracute mattress replacement system.     

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.     

Bed mobility task performance in older adults

Difficulty in transferring, the ability to rise in and out of a bed and chair, is a common problem in older adults, particularly those residing in skilled nursing facilities. Focusing on one aspect of transferring, rising from supine to sitting position, we devised a set of bed mobility tasks to test key arm, leg, and trunk movements that likely contribute to successful rising from bed. Healthy young controls (YC, n=22, mean age 23), and older adults (aged 60 and over) either residing independently in congregate housing (CH, n=29, mean age 84) or undergoing rehabilitation in a skilled nursing facility (SNF, mean age 77) were assessed in the time to rise from supine to sitting and in the ability or inability to perform 16 other bed mobility tasks. Trunk function-related tasks, specifically those requiring trunk elevation and trunk balance, were most difficult for the SNF, followed by CH, and then YC. Tasks focusing on trunk flexion strength (sit up arms crossed, bilateral heel raise) and lateral trunk strength/balance were the most difficult for both SNF and CH, although there was minimal difference in the percent unable to complete each task. The major CH-SNF differences occurred in trunk elevation tasks where the upper limb was important in facilitating trunk elevation (sit up with head of bed elevation with use of arms, sit up with the use of a trapeze, or sit up with use of arms from a flat bed position). These findings suggest that to improve frail older adult performance on bed mobility tasks, and specifically in rising from supine to sitting, training should move beyond improving trunk function (i.e., trunk strength). There should be an additional focus, either through therapy or bed design modifications, on how upper limb movements and positioning can be used to assist in trunk elevation.     

ProfiCare: an alternating pressure-relieving mattress

Risk assessment tools should only act as a guide to patient status rather than definitive diagnosis. Emphasis must be placed on not using the Waterlow score in isolation but in conjunction with clinical judgement. We must therefore attempt to minimize opportunities for disagreement over pressure ulcer risk scores through the selection of appropriate support surfaces based on a thorough consideration of costs of pressure ulcers for the patients, institutions and healthcare professionals. This product focus advocates that ProfiCare replacement mattresses are an option as they are designed for use on a hospital bed frame and provide alternating and static patient support surfaces.     

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。     

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.     

Alternating pressure air mattresses as prevention for pressure ulcers: a literature review

OBJECTIVES: The purpose of this paper is to examine and synthesise the literature on alternating pressure air mattresses (APAMs) as a preventive measure for pressure ulcers. DESIGN: Literature review. DATA SOURCES: PubMed, Cinahl, Central, Embase, and Medline databases were searched to identify original and relevant articles. Additional publications were retrieved from the references cited in the publications identified during the electronic database search. RESULTS: Thirty-five studies were included. Effectiveness and comfort of APAMs were the main focuses of the studies evaluating APAMs. Pressure ulcer incidence, contact interface pressure, and blood perfusion were the most frequently used outcome measures to evaluate the effectiveness of APAMs. Fifteen randomised controlled trials (RCTs) analysed the pressure ulcer incidence. One RCT compared a standard hospital mattress with an APAM and found that the APAM was a more effective preventive measure. RCTs comparing APAMs with constant-low-air mattresses resulted in conflicting evidence. There was also no clear evidence as to which type of APAM performed better. All RCTs had methodological flaws. The use of contact interface pressure and blood perfusion measurements to evaluate the effectiveness of APAMs is questionable. Comfort of APAMs was the primary outcome measure in only four studies. Different methods for assessment were used and different types of APAMs were evaluated. Better measures for comfort are needed. A few studies discussed technical problems associated with APAMs. Educating nurses in the correct use of APAMs is advisable. CONCLUSION: Taking into account the methodological issues, we can conclude that APAMs are likely to be more effective than standard hospital mattresses. Contact interface pressure and blood perfusion give only a hypothetical conclusion about APAMs' effectiveness. Additional large, high-quality RCTs are needed. No conclusions can be drawn regarding the comfort of APAMs. A number of technical problems associated with APAMs are related to nurses' improper use of the devices.     

AN INVESTIGATION OF INTERFACE PRESSURES IN LOW AIR LOSS BEDS

Prospective randomised trials indicate that the low air loss bed is a successful method of treatment for pressure sores. To study the properties of these beds interface pressures were measured in two different low air loss beds. Ten healthy volunteers had eight readings at six different body sites taken supine and sitting. Occipital and heel pressures for both products exceeded 4.7 kPa, the accepted capillary closing pressure, while pressures at other sites were below this. These findings suggest that pressure relief alone is not the sole reason for the clinical acceptance of low air loss beds in the treatment of pressure sores.     

高血压患者不同体位动态血压的监测

目的了解高血压患者仰卧位、侧卧位、坐位、站立位动态血压测量有否不同。方法对51例动态血压监测的高血压患者,选用右上肢肱动脉测压法,分别测量不同体位的血压。结果仰卧位、左侧卧位、右侧卧位、坐位、站立位时的收缩压平均分别是152.10±14.55、129.21±14.92、150.42±15.54、149.87±14.84、147.85±12.67 mm Hg;舒张压平均分别是87.81±6.92、70.83±8.32、88.33±11.52、88.81±9.15、87.25±11.15 mm Hg。与仰卧位时动态血压测量的结果比较,左侧卧位时收缩压平均低22.89 mm Hg,舒张压平均低16.98 mm Hg,P<0.01;右侧卧位时收缩压平均低1.68 mm Hg,舒张压平均高0.52 mm Hg,P>0.05;坐位时收缩压平均低2.23 mm Hg,舒张压平均高1.00 mm Hg,P>0.05;站立位时收缩压平均低4.25 mm Hg,舒张压平均低0.56 mm Hg,P>0.05。结论高血压患者右侧卧位、坐位、站立位时与仰卧位时动态血压测量的结果无明显变化,左侧卧位时动态血压测量的结果显著低于仰卧位时动态血压测量的结果。     

Is fluid filled mattress technology compatible with NICE guidance?

The NICE pressure ulcer guidelines the management of pressure ulcers in primary and secondary care (2005) recommend 'as a minimum provision a high specification foam mattress'. With this statement NICE infers that if quality of care is to be offered, an alternating pressure mattress should be used. In the Newcastle upon Tyne Hospitals NHS Foundation Trust, a new approach to pressure ulcer management has been pioneered, with the introduction of fluid-filled mattresses instead of alternating pressure technology. The Trust has moved to a 98.4% static approach, in effect questioning the NICE guidelines and its recommendations on the selection of appropriate pressure relieving surfaces. Quarterly studies demonstrate a reduction in the prevalence of pressure ulcers as well as significant savings being made, despite an initial financial outlay. The radical move from alternating pressure technology to fluid-filled static technology has been a success: will the same apply to primary care?