Lateral Rotation Mattresses for Wound Healing
Mattresses and beds that move the patient in a regular pattern around a longitudinal (ie, head to foot) axis are variably referred to as lateral rotation, continuous lateral rotation therapy, oscillating therapy, or kinetic therapy.
Although these terms are often used synonymously, one defined technical difference has been noted. According to the Centers for Disease Control's Guideline for the Prevention of Nosocomial Pneumonia,1 kinetic therapy refers to rotation of 40 degrees or more to each side (for an arc of 80 degrees), and continuous lateral rotation therapy rotates up to 40º to each side (up to an 80-degree arc). These specialized mattresses and beds have been used for more than 30 years, mainly in the prevention and treatment of cardio-respiratory conditions in ICU patients. Anecdotally, they have been used to treat skin breakdown in the bedridden, difficult-to-reposition patient. However, scant evidence in the literature addresses the incidence of skin breakdown or the treatment outcome of skin breakdown using these mattresses.
History of the Design
The original design for a rotating bed frame was incorporated in the RotoRest® (Kinetic Concepts Inc., San Antonio, Tex.). This bedframe-and-surface device secures patients in a supine position and rolls or rotates them from left side to right side in a 124-degree arc, or 62 degrees in each direction. Since that time, many devices that turn the patient around a longitudinal axis using various means have been developed. These include other full combination bedframe-and-surface devices and replacement mattresses that turn the patient using either air inflated tubes or pillows. Angles of achievement vary from 60-degree arc, or 30 degrees in each direction, up to the aforementioned 124-degree arc. As a group, these surfaces are commonly referred to as continuous lateral rotation (CLR) or continuous lateral rotation therapy (CLRT).
Other powered support surfaces that are widely used for wound care have been developed, such as low-air-loss and alternating pressure. They are commonly used during the treatment of pressure ulcers, specifically those on the trunk and pelvis, per Medicare guidelines for Group II surfaces.2 The difference between alternating pressure and CLRT is in the pattern of inflation/deflation (see Figure 1).
Cardio-respiratory issues. Research published since 1980 on various CLRT surfaces has centered on cardio-respiratory issues such as decreasing the incidence of atelectasis, pneumonia, and pulmonary compromise in the immobilized patient.3 Despite the number of studies published, drawing firm conclusions is difficult because of the variety of patient populations, bed or mattress features, degrees of patient movement, physiological markers used to identify changes, and results obtained (see Table 1 and Table 2).
Patient populations have included those with acute unilateral pulmonary injury,4,5 closed head injury,6,7 orthopedic injuries,6 penetrating trauma,8 mixed medical/surgical patients,9-14 acute respiratory distress syndrome (ARDS),15,16 or several groups in one study.17 Patient care settings included ICUs of varying specialties4-16 and centers for chronic ventilator-dependent patients.18 Surface features have varied from those with 60 - to those with 124-degree arcs. Some studies do not specify the degree of turn, the frequency of turning, or the amount of time per 24 hours spent in rotation. In one review article, Sahn19 concluded that CLRT must be instituted early to decrease the incidence of lower respiratory tract infections, including pneumonia. Basham et al3 published an extensive and detailed literature review and introduced a tool to identify those patients who might benefit from CLRT.
Most studies compare outcomes on these surfaces to "standard care" or manual turning every 2 hours. However, Krishnagopalan et al20 found that, although clinicians agreed that repositioning every 2 hours was optimal, q2hour repositioning was achieved in only 3% (two of the 74) of ICU patients observed in the study. They concluded that research comparing any type of rotational therapy to manual q2hr turning may be comparing turning to not turning rather than to degree or frequency of turning. Davis15 noted that, although the protocol stipulated turning q2hr, in reality, turning was done every 3 hours. No studies comparing the results of using various degrees of rotation, frequencies of rotation, or the use of mattress vibration/percussion features have been published.
Rotation therapy and skin. Anecdotally, CLRT has been used both to prevent and to heal skin breakdown, but research about the effects of these surfaces on skin is limited. Kirschenbaum18 specified that no difference was found in pressure ulcer incidence between two groups of chronic ventilator patients using either 60-degree arc with vibration/percussion or manual turning q2hr. In a meta-analysis of six studies, Choi21 found no positive or negative effect on the incidence of pressure ulcers with the RotoRest system. Russell14 reported on the incidence of pressure ulcers in an ICU before and after educating the nurses on the need to reposition patients on mattresses that turn patients in a 90-degree arc. The incidence of pressure ulcers in the ICU of that 500-bed tertiary care hospital went from 11 to five in 6 months. Izutsu et al22 used a "rolling air cushion bed" that turns the patient in a 30-degree arc every 15 minutes compared to a control group that was manually turned every 2 hours. The wounds in the study group showed a statistically significant decrease in depth, but not in area, of ulceration while the control group showed no improvement.
In summary, knowledge about the effects of CLRT for pressure-related skin damage is limited. The purpose of this study was to ascertain the effects of CLRT on healing partial- and full-thickness ulcers.
A descriptive study was conducted to record the rate of wound healing and total number of weeks to achieve wound closure in both partial- and full-thickness ulcers when CLRT is employed for skin and wound management. The authors also wanted to compare these rates of healing with other studies reporting wound healing rates to determine if the outcomes on CLRT are comparable. Specifically, the goal of this study was to determine: 1) the rate of wound closure of partial-thickness wounds by area, 2) the rate of wound closure of full-thickness wounds by volume, 3) the number of weeks to closure of partial-thickness wounds, 4) the number of weeks to closure of full-thickness wounds, and 5) the incidence of new skin breakdown while using the CLRT mattress.
Patients. The study population consisted of all patients with a partial-thickness (Stage II) or full-thickness pressure ulcer (Stage III or IV) on the trunk or pelvis using the services of Advanced Therapy Surfaces (ATS), a company that specializes in the rental of support surfaces, between March 15, 2002 and April 1, 2003. In the home care setting, only patients insured under Medicare who met the criteria for a Group II mattress could participate. Medicare requires the home care supplier to have more wound information than private insurances do; thus, access to wound measurements for these patients was available. Long-term care patients who met their facility's criteria for a powered mattress and whose facility allowed ATS to have direct access to the patient or to wound size information also were included.
Because very small wounds can heal quickly, only partial-thickness ulcers with an area of more than .5 cm2 and full-thickness ulcers with a volume (length x width x depth) of more than .5 cm3 were included. Patients were excluded from the study if they died before their wounds closed, changed to another provider and lost services of ATS, or if their wounds were not closed by the end of the study (April 1, 2003). Patients were not excluded for any comorbid factors that are impediments to wound healing such as advanced age, congestive heart failure, diabetes, or smoking.
Materials. Patients received the use of a powered support surface that includes the CLRT modality (PressureGuard APM2, Span-America, Greenville, SC). This mattress turns the patient in a 40-degree arc, 20 degrees to each side, on a 10-minute cycle, six full side-to-side turns per hour.
Caregivers were instructed to reposition patients per their facility protocol, or every 2 hours from side to side or in as many various positions as possible in relation to the mattress surface while not putting pressure on the ulcer site. Even though CLRT mattresses "rotate" the patient, joints, muscles, and organs require regular position changes for stimulation, stretch, and function. Unless manual turning is contraindicated by conditions such as extreme pain with handling, fixed contractures, or medical necessity, CLRT mattresses do not replace the need for manual re-positioning.
Data. Data collected included the date the mattress was placed, wound location and stage, wound measurements (l x w for partial-thickness ulcers and l x w x d for full-thickness ulcers) using the widest or deepest points available on the date of mattress placement, and the date of wound closure. Measurements were taken by the primary nurse involved with each patient. Patients, family, and facility staff were interviewed monthly to assess the incidence of new ulcer development during use of the mattress.
Data were separated into two groups: partial-thickness wounds and full-thickness wounds. Wound area in patients with partial-thickness ulcers was calculated as l x w. Wound volume in full-thickness wounds was calculated as l x w x d. Number of weeks to closure was calculated by subtracting the date of wound closure from the date of mattress placement and rounding to the closest half-week.
Partial-thickness wounds. Initially, 12 patients with 17 wounds were assessed. After excluding patients with wounds smaller than .5 cm2 in area, the group included 10 patients, three with more than one wound (13 wounds total); however, to reduce bias, only one wound per patient was included. The average wound area of the 10 wounds was 12.93 cm2 (SD 16.82 cm2) and the average rate of closure over the study period was 1.42 cm2 (SD 1.31 cm2 or 16.68 %, (SD 10.7%) per week. The average number of weeks to wound closure was 9.5 (SD 6.5) (see Table 3).
Full-thickness wounds. This group initially included 30 patients with 38 wounds. After excluding 10 patients with wounds smaller than .5 cm3 in volume, 20 patients with 23 wounds remained. Again, only one wound per patient was included. The average wound volume was 22.81 cm3 (SD 30.42 cm3) and the average rate of closure was 3.33 cm3 (SD 6.67 cm3) per week or 14.38% (SD 12.50%). The average time to healing was 11.25 weeks (SD 6.61) (See Table 3).
Incidence of new skin breakdown. No new areas of skin breakdown occurred in any of the 30 patients included in this study.
As with all descriptive studies, all patients placed on the mattress were included, regardless of conditions that may affect wound healing. Partial-thickness ulcer data were analyzed separately from full-thickness ulcer data for several reasons. Partial-thickness ulcers involve only the epidermis and part of the dermis and are too shallow to accurately measure depth. Area measurements - ie, simple length and width of the widest points - are, therefore, appropriate for partial-thickness ulcers, as the goal is re-epithelialization rather than filling in volume. Conversely, measuring only the length and width of full-thickness ulcers does not include the depth that must fill in during the healing process. Depth must be used to document healing of full-thickness wounds.
In this study, average rate of wound closure of the partial-thickness wounds was much lower than the rates of full-thickness wounds. This is counterintuitive. One would expect that partial-thickness ("less severe") wounds would close at a faster rate than full-thickness or deep wounds. This discrepancy may be explained, in part, by the fact that partial-thickness or Stage II wounds are often due to friction or maceration and they are easily re-opened by trauma. Therefore, although they may close rapidly, they can also re-open rapidly, and can re-open several times while the mattress is in place. The recorded date of closure may not be the first date of closure, as caregivers may delay return of the mattress until the ulcer(s) did not re-open. Therefore, the data on number of weeks to wound closure and the rate of wound closure of the partial-thickness wounds may be skewed.
The average rate of wound closure per week on the full-thickness wounds was 3.33 cm3, a figure that also seems high. The limitation of the small sample size means that one patient can have an extraordinary effect on the average. In this case, dropping one patient who started with a large wound (106 cm3) would have changed the average rate of wound closure to 1.91 cm3, (SD 2.13 cm3) per week.
The 14.38% average percentage of wound closure of full-thickness wounds per week was much higher than the recently reported 5% per week for wounds in patients placed on low-air-loss mattresses.23 Even after removing the one high outlier patient (baseline wound 106 cm3), the average percentage of wound closure per week remained higher (13.64%) than that reported on low-air-loss.
Sixty percent of the partial-thickness wounds and 55% of the full-thickness wounds closed in 12 weeks. Despite the small number of subjects in this study, these results are similar to, or slightly better than, those recently reported by Bolton et al.24 In their study, when consistent validated protocols of care based on validated standardized wound and patient assessments were applied to 767 wounds in outpatient wound care and long-term care, 61% of the patients with superficial or partial-thickness ulcers and 36% of full-thickness ulcers healed in 12 weeks.
In contrast to Russell14 and to anecdotal reports of CLRT causing skin breakdown, no new ulcers developed. This may be due to teaching caregivers to continue repositioning patients while on the study mattress or to the unique properties of this product that separate it from other products, or a combination of both.
The lack of control inherent in descriptive studies, the small number of wounds in each group, and large standard deviations limit the ability to test for statistically significant differences. Because a mattress is only an adjunct to the total process of wound care and healing, ensuring best practices of good wound care is important to any mattress study. In the role of consultant and clinical support, ATS has no control over direct patient or wound care. The long-term care referral sources are known by the primary author, and standard wound care practices based on moist wound healing are followed in those facilities. For the home care patients, Medicare requires "appropriate wound care" as one criterion for patients on Group 2 surfaces such as the CLRT mattress. However, the authors had no control over the entirety of the patients' wound care programs.
The inclusion criteria did not specify an age limit; however, the criteria for Medicare in homecare, or for residency in a long-term care facility, nearly guarantees the older ages of the participants and, indeed, all were over 60 years old.
Continuous lateral rotation therapy was used as an adjunct to good wound care practices in managing partial-thickness (superficial, or Stage II) and full-thickness wounds (Stage III or Stage IV). Continuous lateral rotation therapy delivered in a 40-degree arc to the selected undiluted population of homecare and long-term care patients appears to assist in the closing of pressure ulcers and demonstrated results comparable to low-air-loss mattresses and outcomes of larger studies. Future studies are needed to compare the use of CLRT to other accepted mattress technologies such as alternating pressure and low-air-loss for pressure-related wounds. In addition, optimal degree and frequency of rotation have not been determined.