Prevention of pressure-induced deep tissue injury using intermittent electrical stimulation

Pressure injury treatment by intermittent electrical stimulation (PROTECT-2): protocol for a multicenter randomized clinical trial

BACKGROUND

Pressure ulcers account for a substantial fraction of hospital-acquired pathology, with consequent morbidity and economic cost. Treatments are largely focused on preventing further injury, whereas interventions that facilitate healing remain limited. Intermittent electrical stimulation (IES) increases local blood flow and redistributes pressure from muscle-bone interfaces, thus potentially reducing ulcer progression and facilitating healing.

METHODS

The Pressure Injury Treatment by Intermittent Electrical Stimulation (PROTECT-2) trial will be a parallel-arm multicenter randomized trial to test the hypothesis that IES combined with routine care reduces sacral and ischial pressure injury over time compared to routine care alone. We plan to enroll 548 patients across various centers. Hospitalized patients with stage 1 or stage 2 sacral or ischial pressure injuries will be randomized to IES and routine care or routine care alone. Wound stage will be followed until death, discharge, or the development of an exclusion criteria for up to 3 months. The primary endpoint will be pressure injury score measured over time.

DISCUSSION

Sacral and ischial pressure injuries present a burden to hospitalized patients with both clinical and economic consequences. The PROTECT-2 trial will evaluate whether IES is an effective intervention and thus reduces progression of stage 1 and stage 2 sacral and ischial pressure injuries.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05085288 Registered October 20, 2021.

Ethics and the emergence of brain-computer interface medicine

Brain-computer interface (BCI) technology will usher in profound changes to the practice of medicine. BCI devices, broadly defined as those capable of reading brain activity and translating this into operation of a device, will offer patients and clinicians new ways to address impairments of communication, movement, sensation, and mental health. These new capabilities will bring new responsibilities and raise a diverse set of ethical challenges. One way to understand and begin to address these challenges is to view them in terms of the goals of medicine. In this chapter, different ways in which BCI technology may subserve the goals of medicine is explored. This is followed by articulation of additional goals particularly relevant to BCI technology: neural diversity, neural privacy, agency, and authenticity. The goals of medicine provide a useful ethical framework for the introduction of BCI devices into medicine.

Effects of Electrical Stimulation on Risk Factors for Developing Pressure Ulcers in People with a Spinal Cord Injury: A Focused Review of Literature

Pressure ulcers (PUs) are a common and serious problem for wheelchair users, such as individuals with a spinal cord injury (SCI), resulting in great discomfort, loss of quality of life, and significant medical care costs. Therefore, it is of utmost importance to prevent PUs. In this literature overview, the effects of electrical stimulation (ES) on the risk factors for developing PUs in people with an SCI are examined and synthesized from January 1980 to January 2015. Thirty-four relevant studies of PU prevention in SCI were identified. Four were randomized clinical trials, 24 were case series, 6 had other designs. Three types of ES modalities were identified. The methodological quality varied from poor to fairly strong, with a large variety in used ES parameters. Twenty-three studies were identified describing short-term effects of ES on interface pressure, oxygenation, and/or blood flow, and 24 studies described the long-term effects of ES on muscle volume, muscle strength, and histology. Whereas there is a lack of controlled studies on the effects of ES on PU incidence, which disallows definite conclusions, there is moderate evidence to suggest that ES-induced muscle activation has a positive influence on several risk factors for developing PUs in people with an SCI.

A Feasibility Study of Intermittent Electrical Stimulation to Prevent Deep Tissue Injury in the Intensive Care Unit

Objective: The primary goal of this study was to investigate the feasibility of utilizing intermittent electrical stimulation (IES) in an intensive care environment as a potential method for preventing pressure ulcers. Furthermore, we wished to evaluate the practicality of the innovation and end-user acceptability. Approach: Twenty immobile subjects, age ranging from 19 to 86 years old with a Braden Scale score ranging from 9 to 16 (very high to moderate risk of developing pressure ulcers), were enrolled. Intermittent 35 Hz electrical stimulation was administered through surface electrodes to the gluteal muscles causing them to contract for 10 s every 10 min. Subjects utilized IES on a program that increased from 4 to 24 h per day over 8 days and lasted up to a maximum of 4 weeks. Results: Bedside nurses reported that IES was simple to use, took an average of 6 min to apply, and 2 min to remove. Furthermore, IES could be easily incorporated into routine patient care. No pressure ulcers occurred in any subject during the study. No untoward reactions or adverse events had occurred directly as a result of IES. Innovation: IES represents a potential method of preventing bedsores. This study represents a necessary pilot study, investigating safety and feasibility before proceeding with a larger randomized controlled trial to determine efficacy. Conclusion: Our results suggest that IES is both safe and feasible to implement in intensive care units.

REVIEW: HEMODYNAMIC STUDIES FOR LOWER LIMB AMPUTATION AND REHABILITATION

No matter what the reason and level of amputation are, amputees will face many complex postoperative problems and potential complications. From the perioperative stage to lengthy rehabilitation process, patients need comprehensive and cautious therapies to help them rebuild their physical and mental health. Although there is some scattered information, the achievements of hemodynamic study for lower limb amputation and rehabilitation have not been systematically classified and summarized. The purpose of this review is to introduce and discuss the hemodynamic issues in preoperative diagnosis, surgical techniques and postoperative problems in the past two decades. Whether from clinical or biomechanical perspective, the investigations of the former two stages have been relatively mature and gained some clear outcomes, even if some conclusions are conflicting and controversial. While in terms of the postoperative problems, such as the common pressure ulcers, DTI and muscle atrophy, there is a lack of vascular or blood flow state studies specifically for lower residual limb. Therefore, the future research focus of hemodynamics for lower limb amputation should probably be the detailed investigations on the relationships between various blood flow parameters and certain common complications. Although hemodynamic research has made some achievements at this stage, it is believed that more advanced and reliable techniques are pending for further explorations and developments.

Vibration inhibits deterioration in rat deep-tissue injury through HIF1-MMP axis

Deep-tissue injury (DTI) is a unique type of pressure ulcer (PU) in which deep-tissue damage expands outwards to the superficial skin. DTI progresses rapidly into a severe PU, despite initially appearing as only a bruise or darkened tissue in the superficial skin. Although some DTI detection methods are available, there is currently no strategy for treating deteriorating DTI. This study investigated the efficacy of vibration therapy for preventing DTI deterioration through down-regulation of the hypoxia-inducible factor-1 matrix metalloproteinase (MMP) axis in rats. We prepared a conventional PU rat model (PU group) and a DTI deterioration rat model (DTI group). The DTI group was further divided into two groups subjected to vibration and control treatments, respectively. Macroscopic and histological features, hypoxia, oxidative stress, apoptosis, and MMP2 and MMP9 activities in compressed skin were analyzed. Hypoxia, oxidative stress, and MMP activity were enhanced in the DTI group compared with the PU group. Vibration remarkably inhibited DTI deterioration, hypoxia, and the expression/activities of MMP2 and MMP9. These results suggest that vibration therapy can effectively attenuate deterioration of DTI. This report provides the first evidence for a therapeutic treatment for deteriorating DTI.

Safety and Feasibility of Intermittent Electrical Stimulation for the Prevention of Deep Tissue Injury

Objective: To investigate the safety, feasibility, and acceptability of a novel treatment, intermittent electrical stimulation (IES), for preventing deep tissue injury (DTI) in different healthcare settings. Approach: Testing was conducted in an acute rehabilitation unit of a general hospital, a tertiary rehabilitation hospital, a long-term care facility, and homecare (HC). IES was delivered through surface electrodes placed either directly on the gluteal muscles or through mesh panels inside a specialized garment. Study participants at risk for DTI used the system for an average of 4 weeks. Outcome measures included skin reaction to long-term stimulation, demands on the caregiver, stability of induced muscle contraction, and acceptability as part of the users' daily routine. Results: A total of 48 study participants used the IES system. The system proved to be safe and feasible in all four clinical settings. No pressure ulcers were observed in any of the participants. There was no difference between the clinical settings in patient positioning, ease of finding optimal stimulation site, and patient acceptance. Although donning and doffing time was longer in the long-term care and HC settings than the acute rehabilitation unit and tertiary rehabilitation facility, time required to apply the IES system was <18 min (including data collection). The patients and caregivers did not find the application disruptive and indicated that the stimulation was acceptable as part of their daily routine in over 97% of the time. Innovation and Conclusion: We demonstrated the safety, feasibility, and acceptability of a novel method of IES to prevent DTI in a continuum of healthcare settings.

Noninvasive evaluation of electrical stimulation impacts on muscle hemodynamics via integrating diffuse optical spectroscopies with muscle stimulator

Technologies currently available for the monitoring of electrical stimulation (ES) in promoting blood circulation and tissue oxygenation are limited. This study integrated a muscle stimulator with a diffuse correlation spectroscopy (DCS) flow-oximeter to noninvasively quantify muscle blood flow and oxygenation responses during ES. Ten healthy subjects were tested using the integrated system. The muscle stimulator delivered biphasic electrical current to right leg quadriceps muscle, and a custom-made DCS flow-oximeter was used for simultaneous measurements of muscle blood flow and oxygenation in both legs. To minimize motion artifact of muscle fibers during ES, a novel gating algorithm was developed for data acquisition at the time when the muscle was relaxed. ES at 2, 10, and 50 Hz were applied for 20 min on each subject in three days sequentially. Results demonstrate that the 20-min ES at all frequencies promoted muscle blood flow significantly. However, only the ES at 10 Hz resulted in significant and persistent increases in oxy-hemoglobin concentration during and post ES. This pilot study supports the application of the integrated system to quantify tissue hemodynamic improvements for the optimization of ES treatment in patients suffering from diseases caused by poor blood circulation and low tissue oxygenation (e.g., pressure ulcer).

Gluteal blood flow and oxygenation during electrical stimulation-induced muscle activation versus pressure relief movements in wheelchair users with a spinal cord injury

BACKGROUND

Prolonged high ischial tuberosities pressure (IT pressure), decreased regional blood flow (BF) and oxygenation (%SO2) are risk factors for developing pressure ulcers (PUs) in patients with spinal cord injury (SCI). Electrical stimulation (ES)-induced gluteal and hamstring muscle activation may improve pressure distribution by changing the shape of the buttocks while sitting and also increase BF and %SO2.

OBJECTIVE

To compare acute effects of ES-induced gluteal and hamstring muscle activation with pressure relief movements (PRMs) on IT pressure, BF and %SO2.

PARTICIPANTS AND METHODS

Twelve men with SCI performed PRMs - push-ups, bending forward and leaning sideward - and received surface ES (87±19 mA) to the gluteal and hamstring muscles while sitting in their wheelchair. Ischial tuberosities pressure was measured using a pressure mapping system; (sub)cutaneous BF and %SO2 were measured using reflection spectroscopy and laser Doppler, respectively.

RESULTS

Compared with rest (156±26 mm Hg), IT pressure was significantly lower during all other conditions (push-ups 19±44; bending forward 56±33; leaning sideward 44±38; ES 67±45 mm Hg). For the whole group, all PRMs significantly augmented BF (+39 to -96%) and %SO2 (+6.0 to -7.9%-point), whereas ES-induced muscle activation did only for peak BF. In all, 63% of the participants showed an increased BF (average 52%) with ES.

CONCLUSION

PRMs acutely reduced IT pressure and improved oxygenation and BF in SCI. The currently used ES method cannot replace PRMs, but it may be used additionally. ES-induced muscle activation is not as effective for acute pressure relief, but the frequency of stimulation is much higher than the performance of PRMs and can therefore be more effective in the long term.

Prevention of deep tissue injury through muscle contractions induced by intermittent electrical stimulation after spinal cord injury in pigs

Deep tissue injury (DTI) is a severe medical complication that commonly affects those with spinal cord injury. It is caused by prolonged external loading of the muscles, entrapping them between a bony prominence and the support surface. The entrapment causes excessive mechanical deformation and increases in interstitial pressure, leading to muscle breakdown deep around the bony prominences. We proposed the use of intermittent electrical stimulation (IES) as a novel prophylactic method for the prevention of DTI. In this study, we assessed the long-term effectiveness of this technique in pigs that had received a partial spinal cord injury that paralyzed one hindlimb. The pigs recovered for 2 wk postsurgery, and subsequently, their paralyzed limbs were loaded to 25% of their body weights 4 h/day for 4 consecutive days each week for 1 mo. One group of pigs (n = 3) received IES during the loading, whereas another group (n = 3) did not. DTI was quantified using magnetic resonance imaging (MRI) and postmortem histology. In the group that did not receive IES, MRI assessments revealed signs of tissue damage in 48% of the volume of the loaded muscle. In the group that did receive IES, only 8% of the loaded muscle volume showed signs of tissue damage. Similar findings were found through postmortem histology. This study demonstrates, for the first time, that IES may be an effective technique for preventing the formation of DTI in loaded muscles after spinal cord injury.

Distribution of internal pressure around bony prominences: implications to deep tissue injury and effectiveness of intermittent electrical stimulation

The overall goal of this project is to develop interventions for the prevention of deep tissue injury (DTI), a form of pressure ulcers that originates in deep tissue around bony prominences. The present study focused on: (1) obtaining detailed measures of the distribution of pressure experienced by tissue around the ischial tuberosities, and (2) investigating the effectiveness of intermittent electrical stimulation (IES), a novel strategy for the prevention of DTI, in alleviating pressure in regions at risk of breakdown due to sustained loading. The experiments were conducted in adult pigs. Five animals had intact spinal cords and healthy muscles and one had a spinal cord injury that led to substantial muscle atrophy at the time of the experiment. A force-controlled servomotor was used to load the region of the buttocks to levels corresponding to 25%, 50% or 75% of each animal's body weight. A pressure transducer embedded in a catheter was advanced into the tissue to measure pressure along a three dimensional grid around the ischial tuberosity of one hind leg. For all levels of external loading in intact animals, average peak internal pressure was 2.01 ± 0.08 times larger than the maximal interfacial pressure measured at the level of the skin. In the animal with spinal cord injury, similar absolute values of internal pressure as that in intact animals were recorded, but the substantial muscle atrophy produced larger maximal interfacial pressures. Average peak internal pressure in this animal was 1.43 ± 0.055 times larger than the maximal interfacial pressure. Peak internal pressure was localized within a ±2 cm region medio-laterally and dorso-ventrally from the bone in intact animals and ±1 cm in the animal with spinal cord injury. IES significantly redistributed internal pressure, shifting the peak values away from the bone in spinally intact and injured animals. These findings provide critical information regarding the relationship between internal and interfacial pressure around the ischial tuberosities during loading levels equivalent to those experienced while sitting. The information could guide future computer models investigating the etiology of DTI, as well as inform the design and prescription of seating cushions for people with reduced mobility. The findings also suggest that IES may be an effective strategy for the prevention of DTI.

Effects of electrical stimulation-induced gluteal versus gluteal and hamstring muscles activation on sitting pressure distribution in persons with a spinal cord injury

STUDY DESIGN

Ten participants underwent two electrical stimulation (ES) protocols applied using a custom-made electrode garment with built-in electrodes. Interface pressure was measured using a force-sensitive area. In one protocol, both the gluteal and hamstring (g+h) muscles were activated, in the other gluteal (g) muscles only.

OBJECTIVES

To study and compare the effects of electrically induced activation of g+h muscles versus g muscles only on sitting pressure distribution in individuals with a spinal cord injury (SCI).

SETTING

Ischial tuberosities interface pressure (ITs pressure) and pressure gradient.

RESULTS

In all participants, both protocols of g and g+h ES-induced activation caused a significant decrease in IT pressure. IT pressure after g+h muscles activation was reduced significantly by 34.5% compared with rest pressure, whereas a significant reduction of 10.2% after activation of g muscles only was found. Pressure gradient reduced significantly only after stimulation of g+h muscles (49.3%). g+h muscles activation showed a decrease in pressure relief (Δ IT) over time compared with g muscles only.

CONCLUSION

Both protocols of surface ES-induced of g and g+h activation gave pressure relief from the ITs. Activation of both g+h muscles in SCI resulted in better IT pressure reduction in sitting individuals with a SCI than activation of g muscles only. ES might be a promising method in preventing pressure ulcers (PUs) on the ITs in people with SCI. Further research needs to show which pressure reduction is sufficient in preventing PUs.

Correlates of new onset peripheral nerve injury in comatose psychotropic drug overdose patients

AIMS

To investigate the relationship between the duration of comatose state, severity of rhabdomyolysis and frequency of peripheral nerve injury (PNI) in patients following psychotropic drug overdose.

MATERIALS AND METHODS

Medical charts were retrospectively reviewed for 41 patients admitted for disturbance of consciousness induced by an overdose of psychotropic drugs with rhabdomyolysis between October 2004 and February 2010. Subjects were divided into PNI group (n=9) and non-PNI control group (n=32).

RESULTS

Mean interval between drug ingestion and arrival, frequency of pressure ulcers, CK level at the time of patient's arrival and maximum CK level during hospitalization, duration of hospitalization and morbidity rate were all significantly higher in the PNI group than in the control group.

CONCLUSION

In patients with a psychotropic drug overdose leading to a comatose state, the longer the comatose state, the more likely that pressure ulcers and PNI will occur.

The effects of intermittent electrical stimulation on the prevention of deep tissue injury: varying loads and stimulation paradigms

A pressure ulcer is a medical complication that arises in persons with decreased mobility and/or sensation. Deep pressure ulcers starting at the bone-muscle interface are the most dangerous, as they can cause extensive damage before showing any signs at the skin surface. We previously proposed a novel intervention called intermittent electrical stimulation (IES) for the prevention of deep tissue injury (DTI). In this study, we tested the effects of four paradigms of IES and one conventional pressure relief paradigm in preventing the formation of deep pressure ulcers in rats. Loading equivalent to 18, 28, or 38% of the body weight (BW) of each rat was applied to the triceps surae muscle in one hind limb. Treatment groups received IES every 10 min for either (i) 5 or 10 s with moderate or maximal contraction, or (ii) complete pressure removal every 10 min for 10 s (conventional pressure relief). The results showed that conventional pressure relief, emulating a wheelchair push-up every 10 min, was inadequate for the prevention of DTI. In contrast, all IES paradigms were equally effective in significantly reducing the extent of deep muscle damage caused by 28 or 38% BW pressure application. These findings suggest that, in conjunction with existing techniques, IES may be an effective intervention for the prophylactic prevention of DTI.

Effects of intermittent electrical stimulation on superficial pressure, tissue oxygenation, and discomfort levels for the prevention of deep tissue injury

The overall goal of this project is to develop effective methods for the prevention of deep tissue injury (DTI). DTI is a severe type of pressure ulcer that originates at deep bone-muscle interfaces as a result of the prolonged compression of tissue. It afflicts individuals with reduced mobility and sensation, particularly those with spinal cord injury. We previously proposed using a novel electrical stimulation paradigm called intermittent electrical stimulation (IES) for the prophylactic prevention of DTI. IES-induced contractions mimic the natural repositioning performed by intact individuals, who subconsciously reposition themselves as a result of discomfort due to prolonged sitting. In this study, we investigated the effectiveness of various IES paradigms in reducing pressure around the ischial tuberosities, increasing tissue oxygenation throughout the gluteus muscles, and reducing sitting discomfort in able-bodied volunteers. The results were compared to the effects of voluntary muscle contractions and conventional pressure relief maneuvers (wheelchair push-ups). IES significantly reduced pressure around the tuberosities, produced significant and long-lasting elevations in tissue oxygenation, and significantly reduced discomfort produced by prolonged sitting. IES performed as well or better than both voluntary contractions and chair push-ups. The results suggest that IES may be an effective means for the prevention of DTI.

Intermittent electrical stimulation redistributes pressure and promotes tissue oxygenation in loaded muscles of individuals with spinal cord injury

Deep tissue injury (DTI) is a severe form of pressure ulcer that originates at the bone-muscle interface. It results from mechanical damage and ischemic injury due to unrelieved pressure. Currently, there are no established clinical methods to detect the formation of DTI. Moreover, despite the many recommended methods for preventing pressure ulcers, none so far has significantly reduced the incidence of DTI. The goal of this study was to assess the effectiveness of a new electrical stimulation-based intervention, termed intermittent electrical stimulation (IES), in ameliorating the factors leading to DTI in individuals with compromised mobility and sensation. Specifically, we sought to determine whether IES-induced contractions in the gluteal muscles can 1) reduce pressure in tissue surrounding bony prominences susceptible to the development of DTI and 2) increase oxygenation in deep tissue. Experiments were conducted in individuals with spinal cord injury, and two paradigms of IES were utilized to induce contractions in the gluteus maximus muscles of the seated participants. Changes in surface pressure around the ischial tuberosities were assessed using a pressure-sensing mattress, and changes in deep tissue oxygenation were indirectly assessed using T₂*-weighted magnetic resonance imaging (MRI) techniques. Both IES paradigms significantly reduced pressure around the bony prominences in the buttocks by an average of 10-26% (P < 0.05). Furthermore, both IES paradigms induced significant increases in T₂* signal intensity (SI), indicating significant increases in tissue oxygenation, which were sustained for the duration of each 10-min trial (P < 0.05). Maximal increases in SI ranged from 2-3.3% (arbitrary units). Direct measurements of oxygenation in adult rats revealed that IES produces up to a 100% increase in tissue oxygenation. The results suggest that IES directly targets factors contributing to the development of DTI in people with reduced mobility and sensation and may therefore be an effective method for the prevention of deep pressure ulcers.

Activation of lower back muscles via FES for pressure sores prevention in paraplegia: a case study

The aim of this paper is to show the feasibility of the use of functional electrical stimulation (FES) applied to the lower back muscles for pressure sores prevention in paraplegia. The hypothesis under study is that FES induces a change in the pressure distribution on the contact area during sitting. Tests were conducted on a paraplegic subject (T5), sitting on a standard wheelchair and cushion. Trunk extensors (mainly the erector spinae) were stimulated using surface electrodes placed on the skin. A pressure mapping system was used to measure the pressure on the sitting surface in four situations: (a) no stimulation; (b) stimulation on one side of the spine only; (c) stimulation on both sides, at different levels; and (d) stimulation at the same level on both sides, during pressure-relief manoeuvres. A session of prolonged stimulation was also conducted. The experimental results show that the stimulation of the erector spinae on one side of the spine can induce a trunk rotation on the sagittal plane, which causes a change in the pressure distribution. A decrease of pressure on the side opposite to the stimulation was recorded. The phenomenon is intensified when different levels of stimulation are applied to the two sides, and such change can be sustained for a considerable time (around 5 minutes). The stimulation did not induce changes during pressure-relief manoeuvres. Finally, from this research we can conclude that the stimulation of the trunk extensors can be a useful tool for pressure sores prevention, and can potentially be used in a routine for pressure sores prevention based on periodical weight shifts.

Deep tissue injury rat model for pressure ulcer research on spinal cord injury

Many rat/mouse pressure ulcer (PU) models have been developed to test different hypotheses to gain deeper understanding of various causative risk factors, the progress of PUs, and assessing effectiveness of potential treatment modalities. The recently emphasized deep tissue injury (DTI) mechanism for PU formation has received increased attention and several studies reported findings on newly developed DTI animal models. However, concerns exist for the clinical relevance and validity of these models, especially when the majority of the reported rat PU/DTI models were not built upon SCI animals and many of the DTI research did not simulate well the clinical observation. In this study, we propose a rat PU and DTI model which is more clinically relevant by including chronic SCI condition into the rat PU model and to simulate the role of bony prominence in DTI formation by using an implant on the bone-tissue interface. Histological data and imaging findings confirmed that the condition of chronic SCI had significant effect on pressure induced tissue injury in a rat PU model and the including a simulated bony prominence in rat DTI model resulted in significantly greater injury in deep muscle tissue. Further integration of the SCI condition and the simulated bony prominence would result a rat PU/DTI model which can simulate even more accurately the clinical phenomenon and yield more clinically relevant findings.