Keywords

alternating pressure, immobility, long-term care, mechanical ventilation, postacute care, pressure injury, support surface

 

Authors

  1. Stone, Arthur DPM

ABSTRACT

BACKGROUND: Pressure injuries (PIs) are a significant concern for patients with very limited mobility in skilled nursing facilities. Conflicting clinical guidelines and a lack of effectiveness data for the various support surfaces reduces the efficacy of PI prevention programs.

 

OBJECTIVE: To assess the preventive effectiveness (incidence of facility-acquired PIs) of a low-profile alternating pressure (AP) support surface plus facility-specific PI prevention programs in patients at high risk for PI.

 

DESIGN AND SETTING: Prospective, multicenter, point-of-care observational study in two for-profit nursing homes in the northeastern US.

 

PATIENTS AND INTERVENTION: A retrospective review of 101 residents was performed to determine baseline PI incidence. Then, a consecutive sample of 25 participants was selected based on the following eligibility criteria: high risk for PI, bedbound (20 hours or more per day), and stay in a mechanical ventilation unit for more than 5 days. The participants were placed on an AP overlay positioned above a facility-provided nonpowered reactive support surface.

 

MAIN OUTCOME MEASURE: The development of any new PI (stage 1-4), deep-tissue injury, or unstageable PI in participants using the AP overlay. The PI incidence for the AP group was compared with the retrospective baseline PI incidence from the same units in the two nursing homes.

 

MAIN RESULTS: The group using the AP overlay had a significantly lower PI incidence (0/25, 0%) compared with baseline (22/101, 21.8%; P < .001). Almost 80% of the study participants in the AP group were completely immobile, 100% of the participants were bowel- and bladder-incontinent, their average time on the AP overlay was 140.9 +/- 94.1 days, and average length of stay in the facility was 633.9 +/- 1,129.1 days.

 

CONCLUSIONS: The low-profile AP overlay was significantly more effective than facility-specific prevention programs alone in preventing PIs in a high-risk nursing home population over an extended period.

 

Article Content

INTRODUCTION

According to the National Center for Health Statistics, the number of Americans 65 years or older in 2015 was almost 48 million, and this number is expected to almost double by 2050.1 The lifetime probability of becoming cognitively impaired or disabled in at least two activities of daily living is 68% for people 65 years or older.2 This vulnerable population may require extended stays in a postacute long-term care facility such as a skilled nursing home because of their disabilities and impairments. In 2012, there were 1.35 million people residing in nursing homes in the US.3 Reduced mobility and cognitive impairment may restrict these residents to staying in bed most of the time. Prolonged pressure over bony prominences, such as those experienced during long periods of immobilization, increases the risk for developing a pressure injury (PI), also known as pressure ulcer, decubitus ulcer, or bedsore.

 

A PI is localized damage to the skin and/or underlying soft tissue as a result of pressure or pressure in combination with shear.4 The injury usually occurs over a bony prominence such as the sacrum or heel. Almost 11% of long-term care residents in the US develop a PI during their stay; prevalence can exceed 20%.5,6 Individuals in nursing homes, especially those receiving mechanical ventilation, are at increased risk for developing a PI because of lack of mobility, decreased oxygen delivery, and poor nutrition status.7 Pender and Frazier8 reported PI incidence of 20% (n = 40) for intubated patients admitted to the ICU of a Midwestern hospital in the US. Senturan et al9 reported an incidence of 16.7% (n = 30) for ventilated patients in a surgical ICU. Treating PIs can be very expensive (~$20,900-$151,700 per patient), and the total annual cost for treating nursing home PIs in the US is estimated at $3.3 billion.10

 

Long-term care settings have implemented multicomponent and interprofessional PI prevention initiatives to improve processes of care and reduce PI incidence in their facilities.11 In 2014, the Office of the Inspector General published an incidence report identifying PI as the most common temporary harm event reported for nursing home resident care.12 Repositioning, a standard prevention procedure in residents at risk for PIs, is applied only in approximately 16% of residents in daily practice. This low adherence has been attributed to caregivers who are not willing to disturb the privacy and sleep of the residents and the high, physical workload of the nursing staff.13

 

Repositioning mechanically ventilated patients for PI prevention can be challenging or contraindicated, and caregivers tend to rely more on support surfaces for prevention. Further, the risk reduction strategies for PIs and ventilator-associated pneumonia (VAP) are in conflict. The head of bed (HOB) is kept elevated (typically 30[degrees] or higher) to assist pulmonary function and reduce risk for VAP in mechanically ventilated patients.14 Although elevating the HOB can assist with ventilation, it can result in patients sliding down the bed, causing increased shear and loading of the sacrum and coccyx, increasing the risk for PI.

 

Accordingly, support surfaces play an important role in preventing and treating PIs, especially in patients with significant immobility. Well-designed support surfaces help redistribute patient load over a large contact area, reducing pressure under bony prominences. Support surfaces or mattresses are broadly classified by the National Pressure Injury Advisory Panel (NPIAP) into reactive and active support surfaces.4 Reactive surfaces (powered and nonpowered) change their load distribution properties in response to an applied load through immersion and envelopment. Active support surfaces are powered surfaces (with various air cell thickness, inflation/deflation durations, and physical properties) that can change load distribution with or without an applied load (periodic pressure reduction). An overlay is an additional support surface (powered or nonpowered, active or reactive) placed on top of another support surface, usually a nonpowered and reactive mattress. Although numerous types of mattress and overlay products are available, clinical evidence demonstrating their effectiveness is limited or unavailable, leading to inappropriate or ineffective use of these support surfaces. Specialty mattresses are expensive and, in some cases, might increase the risk for certain adverse events such as falling/slipping out of the bed or shear and entrapment from the increased height of the mattress.

 

The purpose of this pilot study was to explore the clinical benefits of a low-profile alternating pressure (AP) overlay (Dabir Surfaces Inc, Chicago, Illinois) compared to facility-specific programs alone for preventing PI in nursing home patients-especially those receiving mechanical ventilation or at high risk for developing PI.

 

METHODS

A point-of-care, multicenter, prospective observational study was conducted from December 2017 to September 2018 in two for-profit long-term care/skilled nursing facilities. Residents who were bedbound because of very limited mobility were selected by the facility's wound care team for enrollment. The Western Institutional Review Board in Puyallup, Washington, approved the study. The wound care team provided potential study participants and/or their family (based on the participant's cognitive status) with information about the study and obtained verbal consent. The requirement for written consent was waived by the institutional review board under 45 CFR 46.116(d).

 

Study participants were primarily enrolled from the ventilation units because these residents were bedbound with very limited mobility (Braden mobility, activity, and friction subscale scores of 1 or 2), incontinent of bowel and bladder, and therefore at high risk for developing a PI. Inclusion criteria were being older than 18 years and staying in a ventilation unit for at least 5 days. Exclusion criteria were the presence of PI on admission, open wounds in areas that were in contact with support surfaces, body weight more than 400 lb, and/or patients requiring use of a powered mattress.

 

Facility PI Prevention Program (Standard of Care)

Residents requiring mechanical ventilation are admitted to ventilation units and are typically placed on a nonpowered pressure redistribution mattress. Preventive steps typically employed for reducing facility-acquired PIs include skin risk assessment, use of viscoelastic pressure redistributing foam mattress, maintaining HOB elevation at 30 degrees or lower if allowed, daily skin observations and weekly skin inspections, and nutrition/hydration and fecal/urinary incontinence monitoring. If a resident has a PI, its progress is monitored and documented in the Skin Integrity Report on a weekly basis. The NPIAP guideline is used to stage PIs.15 Positioning/repositioning devices (such as heel-lift devices, positioning pillows, wedges) and specialty mattresses (such as low-air-loss mattresses) are provided as needed. Once patients in the ventilation units are successfully weaned, they are transferred to other units with a tracheostomy collar.

 

Prospective Overlay Group (Intervention)

Mechanically ventilated residents or those at very high risk for PI were placed on an AP overlay positioned on top of a facility-provided pressure redistribution foam mattress (Figure 1). The low-profile AP overlay (less than an inch in height when fully inflated) consists of hundreds of closely spaced nodes arranged in rows. These rows can be alternately inflated, providing periodic pressure reduction for body areas vulnerable to PIs while minimizing shear and entrapment risk (Figure 2). A fitted sheet was placed over the AP overlay, and the overlay was turned on whenever the resident was in the bed. All other procedures/protocols followed in the AP group were the same as standard of care.

  
Figure 1 - Click to enlarge in new windowFigure 1. LOW-PROFILE ALTERNATING PRESSURE (AP) SURFACE PLACED OVER A NONPOWERED MATTRESS AND CONNECTED TO A CONTORLLERIllustration courtesy of Dabir Surfaces, Inc.
 
Figure 2 - Click to enlarge in new windowFigure 2. ALTERNATING PRESSURE OVERLAYThe overlay consists of closely placed air cells arranged in rows and alternately inflated (blue rows, indicated by bold arrows) and deflated (white rows, indicated by dotted arrows).Illustration courtesy of Dabir Surfaces, Inc.

Outcomes and Endpoint

The primary outcome measure was the development of any new PI (stage 1-4), deep-tissue injury, or unstageable PI in the participants using the AP overlay. The prevention effectiveness of the AP overlay was compared with historical PI incidence for patients from the same units.

 

Basic demographic, routine skin assessment, and support surface information was collected for study participants in the AP group, including age, sex, body mass index, Braden Scale score, whether the participant was admitted to the ventilation unit from a nursing home or acute care, primary diagnosis and comorbid conditions, mobility and nutrition status, history of previous PI, bowel and bladder incontinence, skin assessment frequency, type of support surface used and the HOB angle, overall length of stay in the nursing facility from admission to study start, and number of days on the AP overlay.

 

Outcomes data were followed for the period AP overlay was used by the study participant. Because of limited access and partial availability of data in the retrospective group, comparisons between the retrospective standard-of-care and prospective AP groups were not possible.

 

Procedure

A retrospective review (December 2016 through June 2017) of patients admitted to the ventilation units at the two skilled nursing facilities was performed by the respective wound care nurse supervisor. Patient identifiers were not collected as part of the review. Related skin documentation and skin integrity notes were then reviewed by the study author to obtain baseline PI incidence (historic control). Given the extended length of stay in the facility (in years) for some of the residents in the prospective AP group, they were also included in the retrospective group reviewed to establish baseline incidence.

 

For the prospective portion of the study, the principal investigator along with wound care nurses at the two facilities organized two education programs for the clinical team to familiarize them with the study device and protocol. Hands-on training was provided at study roll-out to the clinical team. The wound team nurse supervisor reviewed the residents, identified participants based on study selection criteria, and informed the eligible residents and/or their representatives about the study. The AP overlay was placed on top of a nonpowered pressure redistribution mattress and a fitted sheet placed on top of the overlay. For participants using a powered mattress because of their high-risk status, a replacement nonpowered mattress was provided, and the AP overlay was placed on top. Wound care nurses collected demographic and baseline clinical information. The study was rolled out at one site initially, and started at the second site 3 months later.

 

Data Analysis

For sample size calculation (dichotomous endpoint, two independent groups), the baseline incidence was set at 22%, and the AP group incidence at 1%. The significance level ([alpha]) was set at .05, and the power (1 - [beta]) at 0.80. A 3-to-1 (historical standard of care to AP) proportion was used for sample size allocation. A sample size of 24 residents was required for the prospective AP overlay group.

 

Daily skin observations and weekly skin inspections were used to identify the development of a new PI (dichotomous) in the AP group. Categorical data are presented as counts and percentages, whereas continuous data are presented as means and SDs or ranges. An intention-to-treat analysis was performed. A two-sided P < .05 was considered statistically significant.

 

RESULTS

A total of 22 facility-acquired PIs (any stage PI, deep-tissue injury, unstageable) were identified in the 101 residents reviewed for an overall baseline incidence of 21.8% (22/101) in the retrospective population (standard of care). Eight of the 22 PIs were stage 3 or 4, with heel and sacrum accounting for most of the PIs (Table 1). This baseline incidence is similar to those reported by Pender and Frazier8 (n = 40, 20%) and Senturan et al9 (n = 30, 16.7%) in mechanically ventilated patients, albeit in an acute care setting.

  
Table 1 - Click to enlarge in new windowTable 1. FACILITY-ACQUIRED PRESSURE INJURIES IN STANDARD-OF-CARE GROUP (N = 101)

Twenty-five residents admitted to ventilation units at two long-term care skilled nursing facilities (age, 64.4 +/- 18.9 years [range, 31-98 years]; weight, 167.9 +/- 53.1 lb [range, 72.2-256.2 lb]; body mass index, 26.6 +/- 8.0 kg/m2 [range, 13.2-40.2 kg/m2]) participated in this study (Table 2). The participants were in the two nursing facilities for an average of 633.9 +/- 1,129.1 days (range, 64-4,612 days) prior to enrollment. The AP overlay was turned on whenever the participant was in bed. The average time spent on the AP overlay was 140.9 +/- 94.1 days (range, 7-258 days), with 11 participants using the AP overlay for more than 6 months continuously.

  
Table 2 - Click to enlarge in new windowTable 2. PATIENT CHARACTERISTICS, OVERLAY GROUP

The wound team at the two nursing facilities assessed study participants to be at high PI risk based on various factors. The average Braden Scale score was 13.1 +/- 2.9 (range, 8-18), indicating participants were at moderate risk. However, almost 80% of the participants were completely immobile (Braden subscale scores for activity, mobility, and friction were mostly 1s and 2s), 100% were bowel and bladder incontinent, 70% had a primary diagnosis related to pulmonary function, and 62% had a history of previous PI. Higher subscale scores (3s and 4s) for nutrition, sensory perception, and moisture raised the overall Braden score to moderate risk.

 

The participants were primarily placed on a viscoelastic pressure redistribution mattress (88%), a step above the standard pressure redistribution mattress provided to other residents. In one of the facilities, at the discretion of wound team and clinical leadership, some residents were placed on a powered low-air-loss mattress. Because of pulmonary complications, the HOB was placed in an elevated position (30[degrees] to 45[degrees]) for almost all participants (96%), thus increasing the risk for developing a PI.

 

None of the study participants in the AP group developed any PI during the study period, compared with the 21.8% baseline incidence (P <.001) observed during the retrospective review.

 

DISCUSSION

In this prospective observational study, two nursing home facilities implemented a low-profile AP overlay system for preventing PIs in high-risk mechanically ventilated patients. None of the 25 patients requiring a ventilator and using the AP overlay developed any PIs during the study period, compared with 22% at baseline-and 11 patients used the AP overlay continuously for more than 6 months.

 

Current clinical practice guidelines recommend using appropriate support surfaces and frequently repositioning patients to minimize prolonged tissue deformation, reduce shear, and improve tissue perfusion. Implementing PI prevention guidelines in patients using mechanical ventilation can be challenging because of conflicting recommendations-PI prevention guidelines recommend a HOB angle less than 30[degrees], whereas VAP prevention guidelines recommend a HOB angle greater than 30[degrees].16 Increasing the HOB angle to 30[degrees] and higher significantly increases skin shear and interface pressure in the sacral-coccygeal area. Prolonged loading without frequent and effective repositioning increases the risk of developing a PI. In this study, participants, in accordance with the facility's PI prevention protocol, were placed on a viscoelastic pressure redistribution mattress with the HOB angle at 30[degrees] to 45[degrees] to assist pulmonary function.

 

Patient repositioning, a key recommendation of all PI prevention guidelines, has limited and mixed evidence, especially regarding the repositioning frequency (every 2, 3, 4, or 6 hours) and its effect on preventing PIs.17-19 Sharp et al20 observed in a multicenter study that even with repositioning every 2 hours, a third of the residents in residential aged care facilities in Australia developed PIs. Multiple studies have also reported low adherence to repositioning protocols by care providers for various reasons: sleep disruption, inadequate caregiver knowledge, high workload, and staff shortages.21,22

 

Support surfaces play an important role in preventing and treating PIs, especially in patients with significant immobility. According to the NPIAP's International Clinical Practice Guideline,4 support surface characteristics such as immersion, envelopment, and heat and moisture permeability vary substantially from device to device both within and across categories (active or reactive). Although the reactive surface (such as the viscoelastic mattress used by the facilities) provides deep immersion and a high degree of envelopment to spread the body load over a large contact area, active surfaces periodically shift the areas of support among anatomical locations so that deformation is not sustained at any one area. Laboratory or outcome studies demonstrating the effectiveness of support surface products in preventing PIs are limited or unavailable. Also, the conclusions from these limited studies are mixed and may not reflect new technologies currently available to healthcare facilities.

 

For example, Beeckman et al23 conducted a randomized controlled trial (RCT) to compare the effectiveness of a static mattress with an AP mattress in more than 300 nursing home residents. They reported that the static mattresses were more effective in preventing PIs (5.2% vs 11.7%) and were also cost-effective. Although RCTs are very rare, especially in postacute settings, the generalizability of the study was limited. The 300+ participants were recruited from 26 different nursing homes, and although the participants in the static mattress group received the same type of mattress/cushion/heel protector, those in the AP group had a wide range of nonstandardized AP products (overlay mattress; replacement mattress; or products made by various manufacturers, and with varying sizes and air cells) that limits specific conclusions about product efficacy.

 

Further, the lower cost of the static mattress ([Euro sign]0.74 vs [Euro sign]2.28) seems to be dependent on the endpoint used for cost analysis. The study reported costs at 9 years of use (2-year lifespan for static mattress and 7 years for AP mattress). If the cost analysis was done at 7 years, the AP mattress was cost-effective compared with the static mattress ([Euro sign]0.53 vs [Euro sign]0.69).

 

Several systematic reviews have reported the lack of evidence regarding the relative advantages of higher-specification constant-low-pressure mattresses (eg, static air mattresses) versus AP mattresses in PI prevention.24-26 Other trials27-29 have reported a lower incidence of PI in groups using an AP mattress. Finally, one study found that an AP mattress was more cost-effective compared with a foam (static) mattress for older adult patients who were bedridden for more than 15 hours per day.30

 

Typically, AP mattresses have air cells that are 2 to 4 inches in width and 12 to 25 cm (5-10 inches) in height to provide effective pressure reduction during deflation cycles. A concern with AP mattresses is the introduction of skin stretch/shear when the body hangs unsupported above deflated cells. In addition, the height of an air mattress (reactive or active) can increase risk for entrapment against bed rails, and the potential for the air cell edges to collapse under weight can increase the risk that the mattress will slide during ingress/egress. Finally, the large height differential between inflated and deflated nodes and the alternating inflation/deflation of the air cells can be uncomfortable for some patients and disturb their sleep.26

 

That said, AP overlays (placed over nonpowered static mattresses) have air cells that are 5 to 8 cm (2-3 inches) in height to address some of these concerns. In particular, the AP overlay used in this study has features that are unique and differentiate it from other AP overlays. Its low-profile design (less than an inch in height when fully inflated) along with the closely placed nodes or air cells (1 inch in diameter at the base) helps minimize the risk for stretch/shear during deflation cycles while providing effective micropressure reduction. Unlike typical AP mattresses or overlays, the body movement during inflation-deflation transitions with the study AP overlay is minimal, ensuring a stable surface for sleeping or ingress/egress. Anecdotal feedback from nursing home caregivers and participants during the study indicated good acceptance of the AP overlay with no disturbance of sleep.

 

Karg et al31 demonstrated that using the low-profile AP overlay on top of a static foam OR pad significantly reduced the interface pressure under the sacrum while enhancing the sacral blood flow by almost 80% during the deflation cycles. Other studies32,33 of this AP overlay in long-duration surgeries and ICUs/critical care units suggest that using a nonpowered foam support surface in conjunction with the AP overlay is an effective alternative to expensive active/reactive support surface systems for PI prevention.

 

Strengths and Limitations

To the author's knowledge, PI prevention studies have not been done with mechanically ventilated patients in a postacute setting. Accordingly, the current study provides information for a very vulnerable population in the postacute setting with a high incidence of PI despite prevention efforts. Although the study sample size is small, it was powered based on historic incidence at the participating facility instead of using incidence data from other studies or other locations, providing a more appropriate baseline/preintervention incidence. Some of the study participants used the AP overlay for 6 months or longer, providing valuable long-term data instead of the typical 15 to 30 days in most studies. In addition, some of the study participants were long-term residents (multiple years at the facility) with a history of previous PI at the facility, but nevertheless did not develop a new PI while using the AP overlay over extended periods.

 

Although the current study was intentionally designed as a prospective, point-of-care, and intent-to-treat study, the lack of participant randomization is a limitation. Further, although historic data from the two participating facilities were used to establish a baseline for PI incidence, the absence of complete clinical documentation limited the investigator's ability to conduct matched between-group comparisons and other secondary analysis. Finally, the inclusion of cost data would have been valuable for postacute decision-makers, but the study was not designed to make such comparisons.

 

Although RCTs are considered the standard for clinical trials, independent RCTs face considerable challenges especially in postacute settings because of scarce funds and resources. More large-scale RCT studies that investigate clinical aspects and cost-effectiveness of products/technology are needed in the postacute setting given the rapidly increasing population of people older than 65 years with significant cognitive and mobility issues.

 

CONCLUSIONS

This study investigated the effectiveness of a low-profile AP overlay system for preventing PIs in high-risk mechanically ventilated patients at two nursing home facilities. None of the study participants on the AP overlay developed any PIs during the study period, compared with a 22% baseline incidence. Further, large-scale studies are needed to better understand the efficacy and cost-effectiveness of the AP overlay in various postacute settings.

 

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