Barbara A. Rakel

Infusing research into practice to promote quality care

This article describes the Iowa Model of Research in Practice, a heuristic model used at the University of Iowa Hospitals and Clinics for infusing research into practice to improve the quality of care. The components of the model are presented with examples. The impact of the model on patient, staff, and fiscal outcomes is delineated.

A meta-analysis of effects of heparin flush and saline flush: quality and cost implications.

The purpose of this meta-analysis was to estimate the effects of heparin flush and saline flush solutions on maintaining patency, preventing phlebitis, and increasing duration in peripheral heparin locks. The average effect size (value) across 15 studies with a total sample size of 3,490 was 0573 for patency (clotting). The 95% credibility interval ranged from-.2267 to .3413. The average effect size across 13 studies with a total sample size of 2,356 was -.0757 for phlebittis. The 95% credibility interval ranged from -.2497 to .0983. The average effect size for duration across six samples with a total sample size of 1,960 was -.0550. The 95% credibility interval ranged from -.2424 to .1324. It can be concluded that saline is as effective as heparin in maintaining patency, preventing phlebitis, and increasing duration in peripheral intravenous locks. Quality of care can be enhanced by using saline as the flush solution, thereby eliminating problems associated with anticoagulant effects and drug incompatibilities. In addition, an estimated yearly savings of

Hypoalgesia in Response to Transcutaneous Electrical Nerve Stimulation (TENS) Depends on Stimulation Intensity

109,100,000 to

Predictors of postoperative movement and resting pain following total knee replacement

218,200,000 U.S. health care dollars could be attained.

Effects of transcutaneous electrical nerve stimulation on pain, pain sensitivity, and function in people with knee osteoarthritis: a randomized controlled trial.

UNLABELLED Transcutaneous electrical nerve stimulation (TENS) is an electrophysical modality used for pain management. This study investigated the dose response of different TENS intensities on experimentally induced pressure pain. One hundred and thirty TENS naïve healthy individuals (18-64 years old; 65 males, 65 females) were randomly allocated to 5 groups (n = 26 per group): Strong Non Painful TENS; Sensory Threshold TENS; Below Sensory Threshold TENS; No Current Placebo TENS; and Transient Placebo TENS. Active TENS (80 Hz) was applied to the forearm for 30 minutes. Transient Placebo TENS was applied for 42 seconds after which the current amplitude automatically reset to 0 mA. Pressure pain thresholds (PPT) were recorded from 2 points on the hand and forearm before and after TENS to measure hypoalgesia. There were significant differences between groups at both the hand and forearm (ANOVA; P = .005 and .002). At 30 minutes, there was a significant hypoalgesic effect in the Strong Non Painful TENS group compared to: Below Sensory Threshold TENS, No Current Placebo TENS and Transient Placebo TENS groups (P < .0001) at the forearm; Transient Placebo TENS and No Current Placebo TENS groups at the hand (P = .001). There was no significant difference between Strong Non Painful TENS and Sensory Threshold TENS groups. The area under the curve for the changes in PPT significantly correlated with the current amplitude (r(2) = .33, P = .003). These data therefore show that there is a dose-response effect of TENS with the largest effect occurring with the highest current amplitudes. PERSPECTIVE This study shows a dose response for the intensity of TENS for pain relief with the strongest intensities showing the greatest effect; thus, we suggest that TENS intensity should be titrated to achieve the strongest possible intensity to achieve maximum pain relief.

A new transient sham TENS device allows for investigator blinding while delivering a true placebo treatment

TOC summary Patients with higher pain, increased pain sensitivity, and depression before total knee replacement are more likely to have higher movement pain postoperatively. ABSTRACT This study determined preoperative predictors of movement and resting pain following total knee replacement (TKR). We hypothesized that younger patients with higher preoperative pain intensity, pain sensitivity, trait anxiety, pain catastrophizing, and depression would be more likely to experience higher postoperative movement pain than older patients with lower scores on these variables prior to surgery, and that predictors would be similar for resting pain. Demographics, analgesic intake, anxiety, depression, pain catastrophizing, resting pain, movement pain (ie, during active knee range of motion), and quantitative sensory tests were performed preoperatively on 215 participants scheduled for a unilateral TKR. On postoperative day 2, analgesic intake, resting pain, and movement pain were again assessed. Significant predictors of moderate or severe movement pain were higher preoperative movement pain, von Frey pain intensity, and heat pain threshold. People with severe movement pain preoperatively were 20 times more likely to have severe movement pain postoperatively. When the influence of preoperative movement pain was removed, depression became a predictor. Significant predictors of moderate to severe resting pain were higher preoperative resting pain, depression, and younger age. These results suggest that patients with higher preoperative pain and depression are more likely to have higher pain following TKR, and younger patients may have higher resting pain. Cutaneous pain sensitivity predicted movement pain but not resting pain, suggesting that mechanisms underlying movement pain are different from resting pain. Aggressive management of preoperative pain, pain sensitivity, and depression prior to surgery may facilitate postoperative recovery.

An investigation of the development of analgesic tolerance to TENS in humans

Background Transcutaneous electrical nerve stimulation (TENS) is commonly used for the management of pain; however, its effects on several pain and function measures are unclear. Objective The purpose of this study was to determine the effects of high-frequency TENS (HF-TENS) and low-frequency TENS (LF-TENS) on several outcome measures (pain at rest, movement-evoked pain, and pain sensitivity) in people with knee osteoarthritis. Design The study was a double-blind, randomized clinical trial. Setting The setting was a tertiary care center. Participants Seventy-five participants with knee osteoarthritis (29 men and 46 women; 31–94 years of age) were assessed. Intervention Participants were randomly assigned to receive HF-TENS (100 Hz) (n=25), LF-TENS (4 Hz) (n=25), or placebo TENS (n=25) (pulse duration=100 microseconds; intensity=10% below motor threshold). Measurements The following measures were assessed before and after a single TENS treatment: cutaneous mechanical pain threshold, pressure pain threshold (PPT), heat pain threshold, heat temporal summation, Timed “Up & Go” Test (TUG), and pain intensity at rest and during the TUG. A linear mixed-model analysis of variance was used to compare differences before and after TENS and among groups (HF-TENS, LF-TENS, and placebo TENS). Results Compared with placebo TENS, HF-TENS and LF-TENS increased PPT at the knee; HF-TENS also increased PPT over the tibialis anterior muscle. There was no effect on the cutaneous mechanical pain threshold, heat pain threshold, or heat temporal summation. Pain at rest and during the TUG was significantly reduced by HF-TENS, LF-TENS, and placebo TENS. Limitations This study tested only a single TENS treatment. Conclusions Both HF-TENS and LF-TENS increased PPT in people with knee osteoarthritis; placebo TENS had no significant effect on PPT. Cutaneous pain measures were unaffected by TENS. Subjective pain ratings at rest and during movement were similarly reduced by active TENS and placebo TENS, suggesting a strong placebo component of the effect of TENS.

Transcutaneous electrical nerve stimulation reduces pain, fatigue and hyperalgesia while restoring central inhibition in primary fibromyalgia

UNLABELLED This study compared a new transient sham transcutaneous electrical nerve stimulation (TENS) that delivers current for 45 seconds to an inactive sham and active TENS to determine the degree of blinding and influence on pain reduction. Pressure-pain thresholds (PPT), heat-pain thresholds (HPT), and pain intensities to tonic heat and pressure were measured in 69 healthy adults before and after randomization. Allocation investigators and subjects were asked to identify the treatment administered. The transient sham blinded investigators 100% of the time and 40% of subjects compared to the inactive sham that blinded investigators 0% of the time and 21% of subjects. Investigators and subjects were blinded only 7% and 13% of the time, respectively, with active TENS. Neither placebo treatment resulted in significant changes in PPT, HPT, or pain intensities. Subjects using higher active TENS amplitudes (> or =17 mAs) had significantly higher PPTs and lower pain intensities to tonic pressure than subjects using lower amplitudes (<17 mAs). HPTs and pain intensities to tonic heat were not significantly changed. The transient TENS completely blinds investigators to treatment and does not reduce pain, thereby providing a true placebo treatment. PERSPECTIVE This article presents the benefits of a new transient sham TENS device for use in prospective, randomized, clinical trials. This device facilitates blinding of subjects and investigators to eliminate expectation bias and determine the true efficacy of TENS for use in clinical populations.

Adjusting Pulse Amplitude During Transcutaneous Electrical Nerve Stimulation (TENS) Application Produces Greater Hypoalgesia

&NA; Transcutaneous electrical nerve stimulation (TENS) is a noninvasive modality used to control pain. Animal models show that repeated TENS application produces analgesic tolerance and cross‐tolerance at spinal opioid receptors. The aim of the present investigation was to examine whether repeated application of TENS produces analgesic tolerance in humans. One hundred healthy subjects were randomly assigned to 1 of 4 groups: control, placebo, low‐frequency (4 Hz) or high‐frequency (100 Hz) TENS. TENS was applied daily for 5 days to the nondominant upper limb; pressure‐pain threshold (PPT) measurements were recorded before and after TENS. Temporal summation to mechanical stimulation was recorded on days 1 and 5, before and after TENS. Diffuse noxious inhibitory control (DNIC) was tested on day 5 using the cold pressor test and PPT measurements. There was an initial increase in PPTs in both low‐ and high‐frequency TENS groups when compared with placebo or control groups. However, by day 5 this TENS‐induced increase in PPT did not occur, and there was no difference between active TENS and placebo or control groups. High‐frequency TENS decreased temporal summation on day 1 when compared with day 5. DNIC increased the PPT similarly in all groups. These data suggest that repeated daily application of TENS results in a decrease in its hypoalgesic effect by the fifth day and that the tolerance‐like effect to repeated TENS results from tolerance at centrally located opioid receptors. The lack of change in DNIC response suggests that TENS and DNIC utilize separate pathways to produce analgesia. Repeated high‐frequency and low‐frequency transcutaneous electrical nerve stimulation produce analgesic tolerance in humans by the fourth and fifth day of treatment, respectively.

Using TENS for pain control: the state of the evidence

Summary Pain and fatigue during movement, but not at rest, are reduced by a onetime 30‐m treatment with active transcutaneous electrical nerve stimulation (TENS) in individuals with fibromyalgia. Abstract Because transcutaneous electrical nerve stimulation (TENS) works by reducing central excitability and activating central inhibition pathways, we tested the hypothesis that TENS would reduce pain and fatigue and improve function and hyperalgesia in people with fibromyalgia who have enhanced central excitability and reduced inhibition. The current study used a double‐blinded randomized, placebo‐controlled cross‐over design to test the effects of a single treatment of TENS with people with fibromyalgia. Three treatments were assessed in random order: active TENS, placebo TENS and no TENS. The following measures were assessed before and after each TENS treatment: pain and fatigue at rest and in movement; pressure pain thresholds, 6‐m walk test, range of motion; 5‐time sit‐to‐stand test, and single‐leg stance. Conditioned pain modulation was completed at the end of testing. There was a significant decrease in pain and fatigue with movement for active TENS compared to placebo and no TENS. Pressure pain thresholds increased at the site of TENS (spine) and outside the site of TENS (leg) when compared to placebo TENS or no TENS. During active TENS, conditioned pain modulation was significantly stronger compared to placebo TENS and no TENS. No changes in functional tasks were observed with TENS. Thus, the current study suggests TENS has short‐term efficacy in relieving symptoms of fibromyalgia while the stimulator is active. Future clinical trials should examine the effects of repeated daily delivery of TENS, similar to the way in which TENS is used clinically on pain, fatigue, function, and quality of life in individuals with fibromyalgia.