RESEARCH

Pain Management After Total Knee Arthroplasty A Case–Control Study of Continuous Nerve Block Therapy Karenirene Thomas ▼ Barbara Barrett ▼ Ruth Tupper ▼ Lydia Dacenko-Grawe ▼ Karyn Holm

Continuous femoral nerve block infusions (CFNBIs) have been found to both decrease patient postoperative pain and improve postoperative joint mobilization, both of which impact patient satisfaction, outcome, and length of stay. When we began the use of CFNBIs, we needed to create a policy, process, standing order form, and staff education plan as well as a means to maximize therapy efficacy and believed that a research study would best meet those needs. PURPOSE: To evaluate the patient response to the institution of CFNBI therapy, identify process improvement areas, and suggest areas for future study. METHODS: Through retrospective chart review, using a case–control research design with 27 pairs of patients matched by body mass index, American Society of Anesthesiologists patient physical status classification, and age, we examined whether patients receiving CFNBI therapy after total knee arthroplasty would report less postoperative pain, require less narcotics, and achieve mobilization goals earlier than patients receiving traditional narcotic analgesia only. RESULTS: The CFNBI case group reported significantly less pain over the first three postoperative days (p = .05), but findings revealed no significant differences between case and control groups in total narcotic use or achievement of mobility goals. On the basis of this study, we increased the CFNBI drug concentration and expect that this will allow us to meet all 3 patient goals. CONCLUSION: This study has added to previous research that supports CFNBI as a proven therapy to decrease postoperative pain in patients undergoing total knee arthroplasty. The structure of a research project facilitates the implementation, evaluation, and improvement of such new therapies. Evaluating patient data allows identification of process improvement areas—in our case, the change in drug concentration—as well as the need for staff education aimed at facilitating their active participation in CFNBI therapy. BACKGROUND:

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etween 1996 and 2007, the number of total knee arthroplasty (TKA) procedures increased by 54% for U.S. adults aged 45–64 years and by 37% for U.S. adults aged 65 years and older (Centers for Disease Control and Prevention and The National Center for Health Statistics, 2010). In 2009, 686,000 patients had TKAs compared with 329,000 patients in 1997 (Wier et al., 2011). The population is getting older and increasingly obese, so it can be expected that this growth will continue given the link between age, weight, and TKA (Centers for Disease Control and Prevention [CDC] and Arthritis Foundation, 2010). Total knee arthroplasty has also been reported to be one of the most painful orthopaedic surgeries (Allen, Liu, Spencer, & Ware, 1998; Pitmana-aree et al., 2005). Today’s patients are more aware of healthcare choices than they have been in the past and expect their pain to be controlled. Research continues to find the most effective modalities for pain control.

Karenirene Thomas, RN, CPAN, PACU, Team Leader, St. Francis Hospital of Evanston, Evanston, IL. Barbara Barrett, BSN, RN, MSCRN, Charge Nurse 5 South, St. Francis Hospital of Evanston, Evanston, IL. Ruth Tupper, MS, RN, Nursing Research Consultant, St. Francis Hospital of Evanston, Evanston, IL. Lydia Dacenko-Grawe, BS, BA, RN, BC-CVN, Director of Patient Care Services, St. Francis Hospital of Evanston, Evanston, IL. Karyn Holm, PhD, RN, FAAN, FAHA, Professor, School of Nursing DePaul University/Vincent de Paul, Professor and Nursing Research Consultant, St. Francis Hospital of Evanston, Saint Francis Hospital of Evanston, Presence Healthcare, Evanston, IL. Supplemental digital content is available for this article. Direct URL citations appear in the printed text, and links to the digital files are provided in the HTML text of this article on the journal’s Web site (http://journals.lww.com/orthopaedicnursing). The authors have disclosed no conflicts of interest. DOI: 10.1097/NOR.0b013e3182879bd9 Number 5

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Review of Literature Studies have evaluated the use of various pain treatment modalities regarding patient postoperative pain and postoperative joint mobilization (Beaudet, Williams, Tétreault, & Perrault, 2008; Richman et al., 2006; Toftdahl et al., 2007). The benefits of continuous femoral nerve block infusion (CFNBI) include improved pain control, earlier mobilization, increased patient satisfaction, decreased opioid requirements, and therefore, decreased opioid side effects, as well as decreased metabolic and surgical stress response leading to a decrease in coronary ischemia, deep venous thrombosis, pulmonary embolism, insomnia, pneumonia, poor wound healing, and psychological trauma and/or demoralization (Chelly et al., 2001). Furthermore, Chelly et al. (2001) found that CFNBI reduced narcotic requirements by 74%; decreased postoperative bleeding by 72%; allowed better performance on continuous passive motion therapy; decreased serious complications such as hypotension, bradycardia, transfusions, and fever by 90%; and reduced length of hospitalization by 20%. Pain control and mobilization of patients after open knee procedures have also been shown to affect patient satisfaction, outcome, and length of stay (Ilfeld et al., 2008; Shum et al., 2009). Most studies have examined either postoperative pain or postoperative joint mobilization although postoperative pain control has been shown to directly affect postoperative joint mobilization (Capdevila et al., 2005; Ilfeld & Enneking, 2005; Ilfeld, Wright, Enneking, & Morey, 2005; Ipswich, Woods, O’Connor, & Calder, 2006; Monaghan, Harrington, & Nizai, 2007; Williams et al., 2006). We found that many studies have compared the use of continuous nerve block infusion in both shoulder and lower extremity patients, but none looked at matching patients on the basis of age, American Society of Anesthesiologists patient physical status classification (ASA), and body mass index (BMI), all of which could influence both patient narcotic requirements and mobilization. One group of investigators (Ilfeld et al., 2005) specifically studied gender but found no statistically significant difference between men and women. We did locate a single nursing study that addressed a nurse-led femoral nerve block service specifically for postoperative pain management in patients with femoral fractures (Layzcll, 2007). Finally, we determined that there were no case–control studies of femoral nerve block therapy to manage postoperative pain.

NARCOTIC USE Nonmorphine narcotics were converted to morphine equivalents using “Table D: Pharmacologic Equivalence and Relevant Pharmacokinetic Data for Opioid Agonists” from The Pain Clinic Manual (2nd ed.; Abram & Haddox, 2000) and daily totals calculated (see Table 1).

MOBILIZATION Mobilization was measured on the basis of whether or not the patient achieved an individualized physical therapy (PT) goal of walking a predetermined distance in a set number of PT sessions. These measurements included achievement of the goal (yes or no), the number of PT sessions required to achieve the goal, and the number of days required to achieve the goal (if successfully met).

AMERICAN SOCIETY OF ANESTHESIOLOGISTS PHYSICAL STATUS CLASSIFICATION American Society of Anesthesiologists patient physical status classification was used as one of three criteria to match pairs of patients from the CFNBI and control (non-CFNBI) group and was used to match patients with a similar level of morbidity. Paired patients matched ASA status exactly (see Table 2).

BODY MASS INDEX

Purpose The following goals were developed: (1) to evaluate patient-reported postoperative pain, narcotic use, and mobilization after TKA to determine whether evidence existed that the CFNBI was beneficial to our patients; (2) to identify any process improvement areas; and (3) to look for areas for future study.

Study Definitions

Body mass index was calculated using the English BMI formula: BMI = (weight in pounds/height in inches squared) × 703 (http://www.bmi-calculator.net/bmi-formula.php). Each patient’s BMI on admission was used to match pairs with a BMI within 1.0. The mean BMI was 34.15 with a standard deviation for all 54 patients’ BMI of 5.8.

AGE

PATIENT-REPORTED LEVEL OF PAIN For the purposes of this study, pain measurements were patient-reported pain scores according to a 10-point © 2014 by National Association of Orthopaedic Nurses

visual analog scale (VAS) with 0 representing “no pain” and 10 “the worst pain possible.” The patient-reported VAS scores were averaged for each shift and then further averaged for a daily pain score. The VAS for pain is recognized as valid and sensitive (Brevik, Björnsson, & Skovlund, 2000). According to hospital policy and the VAS, a pain score value of 4 (out of 10) was used as the threshold for moderate pain (see Figure 1). A pain score of 4 out of 10, or 40 mm out of 100 mm using the millimeter pain scale, is accepted as a tolerable pain level (Beaudet et al., 2008; Brodner et al., 2007; DeLoach et al., 1998; Gallagher et al., 2001). According to hospital standards of pain management, the intensity and pain relief as reported by the patient is documented: on admission, after any known pain-producing event, with each new report of pain, and routinely at regular intervals (at least every shift). In addition, standards call for documentation after a sufficient time has elapsed for the medication to have reached peak effect, or within 1 hour of intervention.

Each patient’s age in years on admission was used to match pairs within 5 years. The mean age was 61.46 years with a standard deviation of 9.3 years.

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FIGURE 1. Visual analog scale. The Numeric Pain Scale is one of the simplest measures, with the pain at a particular time being assessed as being from 0 to 10, where 0 is no pain and 10 is the worst pain imaginable. This is sometimes used with the visual analog scale. The Visual Analogue Pain Scale is a simple assessment tool consisting of a 10-cm line with 0 on one end, representing no pain, and 10 on the other, representing the worst pain ever experienced. (www.fibroaction.org/images/content/Pain_ Assessment_VAS_lrg.png). CPMC Sutter Health (www.cpmc.org/learning/douments/pain.html).

Methods

patients who had received CFNBI therapy in addition to other routine methods of pain control including patientcontrolled analgesia (PCA). The control group consisted of patients who had received routine methods of pain control including PCA or nurse-administered intravenous, intramuscular, or oral narcotics without a nerve block. The decision to utilize CFNBI had been decided on a case-by-case basis as determined by the patient,

DESIGN The study design was a retrospective case–control matched pair design. Patients from the case group were matched with those from the control group on the basis of ASA, BMI, and age. The case group consisted of

TABLE 1. CONVERSION TO MORPHINE EQUIVALENTS FOR DAILY PAIN MEDICATION TOTALS Oral

Parenteral

Relative Potency

Bioavailability

30 mg (q 3–4 ATC), 60 mg (q 3–4 intermittent)

10 mg (q 3–4)

1

0.3

90–120 mg (q 12)

NA

1

0.3

3 mg (q 3–4)

1.5 mg (q 3–4)

6–7

0.5

Medication Morphine Morphine (controlled release) Hydromorphone (Dilaudid) Levophanol (Levo-Dromoran)

4 mg (q 6–8)

2 mg (q 6–8)

5

0.5

Meperidine (Demerol)

300 mg (q 2–3)

100 mg (q 3 hours)

1

0.3–0.5

Methadone (Dolophine)

12.5–15 (q 6–8)

10 mg (q 6–8)

1

0.7–0.8

NA

1 mg (q 3–4)

10

NA

Oxycodone (OxyIR, Roxicodone, Percodone)

30 mg (q 3–4)

NA

1

0.6–0.7

Oxycodone (controlled release)

80 mg (q 12)

NA

1

0.6–0.7

180–200 mg (q 3–4)

130 mg (q 3–4)

0.08

0.5

30 mg (q 3–4)

N/A

1

0.3

Oxymorphone (Numorphan)

Codeine/ASA or APAP (Tylenol #3) Hydrocodone/APAP (Vicodin, Lorcet, Lortab, Norco)

Note. ASA = acetylsalicyclic acid (aspirin); APAP = paracetamol (acetominophen); ATC = around the clock; NA = not applicable. From The Pain Clinic Manual (2nd ed.), by S. E. Abram and J. D. Haddox, 2000, Philadelphia, PA: Lippincott Williams & Wilkins.

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TABLE 3. MATCHED PAIRS FROM CASE–CONTROL STUDY OF CONTINUOUS NERVE BLOCK THERAPY AFTER TOTAL KNEE ARTHROPLASTY

TABLE 2. AMERICAN SOCIETY OF ANESTHESIOLOGISTS (ASA) PHYSICAL STATUS CLASSIFICATION SYSTEM ASA Physical Status 1: A normal healthy patient

Number of Pairs

ASA Physical Status 2: A patient with mild systemic disease ASA Physical Status 3: A patient with severe systemic disease

27

ASA Physical Status 4: A patient with severe systemic disease that is a constant threat to life ASA Physical Status 5: A moribund patient who is not expected to survive without the operation

ASA Difference

BMI Difference

Age Difference

0

≤1.0

≤5 years

Note. ASA = American Society of Anesthesiologists physical acuity scale; BMI = body mass index.

ASA Physical Status 6: A declared brain-dead patient whose organs are being removed for donor purposes Note. From Principles and Practice of Anesthesiology: Volume One by M. Rogers, J. Tinker, B. Covino, and D. Longnecker, 1993, St. Louis, MO: Mosby Yearbook. Reprinted with permission of the American Society of Anesthesiologists, 520 N. Northwest Highway, Park Ridge, IL 60068.

surgeon, and anesthesiologist. Factors included but were not limited to patient preference; previous surgery or injury to, or skin breakdown at nerve block placement site; and a preexisting neurologic deficit, circulatory, infection, or pain issue in the affected limb.

all TKA patients. Data extracted for use included the following fields: date, procedure, age, ASA, and BMI (or height and weight) with outcome variables of postoperative pain level, postoperative narcotic use, and achievement of mobilization goals on postoperative days 1, 2, 3, 4, and 5. The data collection form was evaluated for interobserver reliability by having two postanesthesia care nurses review the same charts (see Figure 2). To support content validity, the data collection form was reviewed by an orthopaedic surgeon and an anesthesiologist who determined that the information garnered from the patient charts reflected the purpose of the study.

PILOT STUDY

SETTING The study was conducted at Saint Francis Hospital of Evanston, a 367-bed full-service medical hospital in suburban Chicago. After an initial trial of CFNBI, the Department of Anesthesia recommended the use of this therapy for all TKA procedures. We recognized the need for creating a policy, process, standing order form, and staff education plan. These were implemented in early 2008. Nursing staff in the postanesthesia care unit and the postoperative orthopaedic nursing unit recognized the need for a plan to evaluate patient response and identify areas for process improvement. Staff in each area proposed a plan for a research study to evaluate this therapy. Both units came together to develop a joint research study.

SAMPLE The sample consisted of all patients undergoing primary TKA from August 2008 to July 2009. After the institutional review board approved the study, data were collected from 165 chart reviews allowing for the creation of the 27 matched pairs shown in Table 3. The 54 patients included 37 women and 17 men, with a mean age of 61.46 years and an age range from 45 to 83 years. ASA physical status ratings ranged from 2 to 4, with 20 patients with an ASA rating of 2, 32 patients with an ASA rating of 3, and two patients with an ASA rating of 4. The mean BMI was 34.15 with a range from 23.1 to 48.8 (see Table 4).

MEASUREMENT: DATA COLLECTION TOOL A data collection form was created to assign each patient a number to ensure that patients would remain anonymous. Exclusion criteria prevented unnecessary review of patient records, while enabling investigators to track © 2014 by National Association of Orthopaedic Nurses

After the two primary investigators were certified through completion of computer-based training by the Office of Human Studies Research, National Institutes of Health, a pilot study was done. The pilot study included a sample of five TKA patients with CFNBI and five without, matched as to age, ASA, and BMI. The pilot study was also reviewed by two experts, one orthopaedic surgeon and one anesthesiologist, to ensure validity of the outcomes.

PROCEDURE Crystal Reports version 10 was used to create a formatted data report that extracted all patients having primary TKA for the initial review period from August 1, 2008, through July 30, 2009. This report was later modified to extract potential matches for CFNBI patients in the initial date range and run retrospectively back to January 1, 2008, and from July 31, 2009, to May 31, 2010. Data collection was done by two certified primary investigator registered nurses using a retrospective chart review so as to avoid any direct risk of invading the privacy of the subjects involved. Patient anonymity was further ensured by

TABLE 4. DESCRIPTIVE STATISTICS OF 27 MATCHED PAIRS IN STUDY OF CONTINUOUS FEMORAL NERVE BLOCK AFTER TOTAL KNEE ARTHROPLASTY Age in years

61.46 (mean); 60 (median)

45–83 (range)

Body mass index

34.15 (mean); 35 (median)

23.1–48.8 (range)

Gender

37 women

17 men

Note. n = 54.

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Number assigned: Surgeon: Procedure: Date: Previous open surgery on joint? Paent unable to rate pain on pain scale? pre-op neurological deficit/ pain issues in affected limb? If yes, stop data collecon. Paent meets exclusion criteria.

Aempted (unsuccessful) placement of nerve block catheter? Gender AGE ASA BMI (or height and weight- will calculate BMI later)

height

weight

Indicate Yes or No for next secon quesons pre-op pain score? Intra op pain med/ catheter bolus? Intra arcular On Q Pump? Post-op sensory blockade- Cold percepon measured? Post-op motor blockade- motor scale measured? Adjustment of Nerve block infusion rate? # episodes n/v/use of anemecs?

DOS

PO #1

PO#2

PO#3

PO#4

PO#5

n/v episodes Anemec administraon Adverse effects- list type LOS (days) Adm to unit

next shi

next shi

next shi

next shi

next shi

next shi

next shi

next shi

next shi

next shi

next shi

next shi

next shi

next shi

next shi

next shi

next shi

daily total

daily total

daily total

daily total

daily total

daily total

POD#1

POD#2

POD#3

POD#4

POD#5

Post-op Pain on visual analog pain scale 0-10

Post-op Pain Med use: use new column for each drug Medicaon: Medicaon: Medicaon: Physical Therapy pain and mobilizaon Post-op Pain on visual analog pain scale 0-10 for each PT session Mobilizaon goal achieved for date? Yes or No

Flexion Distance

PT comments/Explanaons: Nerve block catheter removed- Date:

Time:

FIGURE 2. Data collection tool for continuous nerve block therapy study. BMI = body mass index; DOS = day of surgery; LOS, length of stay; PO = postoperation; POD = postoperative day; PT = physical therapy.

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assignment of a number on the data collection sheet, which cannot be traced back to the patient name, account, or medical record. All study documents are being kept in the postanesthesia care unit in a secured area. Postoperative Day 1 covered the time period from admission to the nursing unit until 6:59 a.m. the following morning. The exact number of hours was recorded but not analyzed in this study. Postoperative days 2 and 3 were from 7:00 a.m. to 6:59 a.m., corresponding with daily change from night to day shift. Visual analog scale pain scale scores were averaged per shift on the data collection tool, but a daily average was used and entered on the data analysis Excel spreadsheet and in SPSS Version 20. The demographic data included date of surgery, gender, age, BMI, ASA, procedure and site, length of stay in hours, and the number of hours on nursing unit on the day of surgery. Daily average VAS pain scale score, daily total narcotics in milligrams of morphine equivalents, and achievement of individualized PT therapy goal were entered onto the spreadsheet for subsequent statistical analysis using SPSS Version 20. The expected length of stay for TKA is 72 hours and no patient had been discharged before postoperative Day 3, so the data were analyzed in this time frame (although data were collected for postoperative days 1 through 6). In addition, the daily VAS pain scale score before PT was recorded, if documented, as was the documented daily flexion and ambulation distance achieved.

Results DATA ANALYSIS The mean age for the 54 patients in the study was 61.46 (SD = 9.3; range, 45–83) years, and the mean BMI was 34.15 (SD = 5.8; range, 23–49). The mean age difference between each patient in the 27 matched pairs was 1.78 (SD = 1.53) years, and the mean BMI difference was 0.41 (SD = 0.57). The mean sum of all supplemental narcotics for days 1, 2, and 3 postoperatively was 91.54 mg of morphine (SD = 56.96).

PATIENT-RATED PAIN For the 27 matched pairs, a matched pairs t test analysis showed that patients with the continuous nerve block showed significantly less average pain over the first 3 days postoperatively, t(26) = 2.761, p < .01 (twotailed), r2 = .23, and also showed significantly less pain

on Day 2 postoperatively, t(26) = 3.501, p < .002 (twotailed), r2 = .32 (see Table 5).

NARCOTIC USE Daily narcotic use for the 27 matched pairs ranged from 0 to 177.4 morphine equivalent milligram with a mean of 23.27 on Day 1, 43.34 on Day 2, and 30.62 on Day 3 for the CFNBI group and 30.14 on Day 1, 34.72 on Day 2, and 21.0 on Day 3 for the control group without the nerve block.

PT MOBILIZATION GOAL ACHIEVEMENT Physical therapy mobilization goal achievement was measured as “yes” or “no” goal was achieved, as well as on which session the goal was achieved, if applicable. A total of 24 of 27 of patients with the nerve block achieved mobility whereas 21 of 27 patients without the nerve block did. Because one of the data points (the three who did not achieve mobility with the nerve block) was too small to meet the minimum needed number of 5 for the accuracy of the test, the chi-square test analysis could not be done on the 54 patients representing the 27 pairs.

Discussion CFNBI therapy is a proven therapy to decrease postoperative pain in patients undergoing operative procedures on the lower extremity (Allen et al., 1998; Capdevila et al., 2005; Ilfeld et al., 2008; Richman et al., 2006). Our study replicated the results of these previous studies in regard to reduction in patient-reported postoperative pain only. However, we were unable to replicate results regarding overall narcotic use and mobilization (Chelly et al., 2001; Monaghan et al., 2007; Shum et al., 2009). We did find that 45 of the 54 patients achieved their PT goals. We postulate that this high level of achievement is most likely due to excellent pain control provided to the majority of patients–in both cases and controls—as indicated by the low level of pain reported (the average VAS over the first 3 days postoperatively was 3.1; see Figure 3). We did identify and address the need for revision of physician orders and staff education to better reach the potential of this therapy to meet all three patient goals of decreased pain, decreased narcotic use, and earlier achievement of mobilization. As this was a retrospective study, we would need to extend the chart review into the more recent past to evaluate the success of changes

TABLE 5. EFFECT OF CONTINUOUS NERVE BLOCK THERAPY AFTER TOTAL KNEE ARTHROPLASTY (27 MATCHED PAIRS) Nerve Block, Mean Value (SD)

No Nerve Block, Mean Value (SD)

t Test Result

p

Average pain for days 1, 2, and 3 postprocedure

2.67 (1.15)

3.53 (1.10)

2.76

.010*

Average pain on day 1 postoperation

3.02 (1.50)

3.96 (1.57)

2.051

.051

Average pain on day 2 postoperation

2.53 (1.19)

3.73 (1.44)

3.501

.002*

Average pain on day 3 postoperation

2.46 (1.61)

2.89 (1.19)

1.10

.277

Note. df = 26. *p < .05 (two-tailed).

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FIGURE 3. Pain comparison between patients (27 matched pairs) receiving continuous femoral nerve block infusion therapy and those not receiving therapy in first 3 days after total knee arthroplasty. Pain is on a scale of 0 to 10, using the visual analog scale (VAS), with 0 meaning no pain and 10 meaning the worse pain imaginable. implemented. We did have positive feedback from patients receiving CFNBI therapy as well as from staff and physicians regarding their perception of improved patient experience post-TKA. The Department of Anesthesia and the orthopaedic surgeons at our hospital decided to use a 0.1% ropivacaine concentration in the On Q Pump to ensure that no unintentional motor block would interfere with patient participation in PT sessions. However, studies using a higher ropivacaine concentration of 0.2% have found effective pain control with the use of less narcotics, earlier or better flexibility and mobilization, and shortened length of stay (Barrington et al., 2005; DeRuyter et al., 2006). In particular, one study found that the 0.1% ropivacaine concentration provided inadequate analgesia after knee surgery (Brodner et al., 2007). We have changed our standing order form and protocol to use the 0.2% ropivacaine concentration with the expectation that this will allow us to obtain the goals of decreased narcotic use and earlier mobilization and potentially decrease length of stay.

LIMITATIONS OF THE STUDY We encountered difficulty in matching patients to all three criteria of ASA, BMI, and age, requiring us to expand the time frame by an additional 14 months to find control group matches for 27 of our 83 patients receiving CFNBI therapy. There is the possibility that other procedures or treatment modalities had been implemented or changed during that period that may have affected our outcome variables. As the initial purpose of this study was to ensure that we were providing the best possible experience for our patients receiving this new therapy, we changed our standing order form during the data collection period to promote adjustment of the CFNBI rate and provided more education and one-on-one follow-up with nursing staff. This altering of our practice during the period of data collection could potentially have skewed the results for the case 274

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group. However, as we did not find that the case group used fewer narcotics or met their mobilization goals earlier, it seems that this had no statistically significant effect. Patients were dependent upon the nurse to adjust the rate of the CFNBI in addition to making the decision as to whether to adjust the CFNBI or administer other pain medication. We had identified early on the need for further education and reinforcement for the nurse to adjust the CFNBI before administering other pain medication for these patients. We found that there were significant difficulties in getting nursing staff to make this change in practice from PCA to nurse-controlled CFNBI. One reason for the difficulty was that the process was well established for the administration of PCA. The PCA machine was visible and easily accessible. Nurses routinely reviewed and documented the number of attempts the patients made to self-administer medication, as well as the number of doses of medication the patient received. Standing orders allowed for the adjustment of the PCA dose or frequency or both based on this assessment. The On Q pump, which supplied the CFNBI therapy, in contrast, was less visible under the patient’s blankets. Nurses documented the infusion rate only when they checked the dressing and with any rate change. Except for the order to decrease the rate on postoperative Day 1 at 6:00 a.m. in preparation for PT, there was no scheduled time to adjust the rate. It was at the discretion of the nurse to titrate the infusion. As it is easier to continue well-established practices than integrate new steps into the process, we project that we would have had a better change in practice if we had completely replaced PCA therapy with CFNBI therapy and intravenous narcotics as needed, rather than have both options available for the control group.

NURSING AND CLINICAL IMPLICATIONS With the aging U.S. population and growing obesity problems, it can be anticipated that the number of TKA procedures will continue to increase (CDC and Arthritis Foundation, 2010). Mean BMI has increased for both Number 5

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men and women from 25 in 1960 to 28 in the years between 1999 and 2000 (Ogden, Fryar, Carroll, & Flegal, 2007). The average BMI of the 54 patients in our 27 matched pairs was 34.15. According to the National Institutes of Health, a BMI of 25–29.9 is considered overweight, with a BMI of 30 or greater considered obese (National Institutes of Health, 1998). A total of 35.7% of Americans are obese according to the National Health and Nutrition Examination Survey 2009–2010 (Ogden, Carroll, Kit, & Flegal, 2012). Two of three obese adults will develop joint osteoarthritis and most will require total joint replacement (CDC and Arthritis Foundation, 2010). Maximizing pain management is paramount to obtaining the best patient outcomes, decreasing complications, and reducing hospital costs (Allen et al., 1998; Chelly et al., 2001). The CFNBI therapy is already used in some areas as a safe outpatient or at-home therapy for patients postoperatively (Ilfeld et al., 2005, 2008). As economic pressure continues for hospitals to decrease length of stay, patients are being discharged home earlier and no longer have access to intravenous and intramuscular narcotics for better pain control. The CFNBI can be used as an adjunct with the less potent oral medications to provide needed pain control at home for these patients. Continuous femoral nerve block infusion therapies have been proven to be safe and effective when properly placed and used (Capdevila et al., 2005). We found that a major part of the challenge to the use of this therapy seems to be the reluctance on the part of healthcare professionals to undertake this change of practice. It can be anticipated that this same difficulty may be encountered with making the change to using CFNBI as an athome therapy. Education and active staff participation in the use of this therapy are absolutely necessary. As nurses were responsible for monitoring patient VAS and deciding whether to adjust the CFNBI or administer narcotics or provide other comfort measures, the use of this therapy was completely dependent on their actions. Patient and staff perceptions regarding the efficacy of CFNBI were instrumental in providing the feedback needed for the orthopaedic surgeons to fully embrace and expand their use of CFNBI therapy. Chart review and data collection provided invaluable tools to identify areas for process improvement and staff education. We did find that chart review was extremely time consuming, but it is expected that this process will be greatly streamlined with the change from paper documentation to the electronic medical record. It was our experience that the structure of a research project facilitates the implementation, evaluation, and improvement of new therapies. Development of specific goals enabled definition of the steps needed to be implemented to achieve these goals. Defining groups ensured valid data for comparison. Development of tools to extract and evaluate patient data allowed primary investigators to identify potential areas for improvement during chart review as well as providing a large data pool for postcollection review. The structure of a research project enabled us to refine our focus on what we wanted to achieve for our patients in implementing this therapy as well as providing the means to evaluate interventions © 2014 by National Association of Orthopaedic Nurses

and identify improvements needed. The study also provided a large pool of data that can be used to examine other factors that may impact this patient group.

Conclusion The CFNBI therapy provides improved pain control and can decrease narcotic use, promote earlier mobilization, and decrease morbidity when used to its full potential (Chelly et al., 2001; Oderda et al., 2007). It is a relatively safe therapy with only a few absolute contraindications such as patient refusal, the presence of an active infection at the site of puncture, and true allergy to the local anesthetic. Relative contraindications include the presence of a prosthetic femoral artery graft (Mehrkens & Geiger, 2005; New York School of Regional Anesthesia, 2009). It has the potential for expanded use in the outpatient or home setting (Ilfeld & Enneking, 2005). When implementing a new therapy, it is imperative that disciplines involved come together to develop and implement protocols and order sets where applicable. Although it may have been overly ambitious to match pairs on three criteria leading to difficulty obtaining sufficient subjects, we believe that this strict pairing eliminated factors that could have skewed the data collected, namely BMI, age, and physical acuity. A retrospective chart review provides excellent information to assist in identifying areas where process improvement or protocol change is warranted. Suggested areas of future study include the connection, if any, between BMI and pain, narcotic requirements, mobilization, and/or length of stay. Further evaluation of differences between our matched pairs can be performed regarding length of stay, achievement of PT joint flexion goals and distance achieved, incidence of nausea, and required antiemetic therapy and effect, if any, of administration of nonnarcotic analgesics on patient outcomes. For more information on this study, see the online-only Addendum (Supplemental Digital Content 1, http//links.lww.com/ONJ/A5).

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ropivacaine for continuous femoral nerve blockade. Anesthesia & Analgesia, 105(1), 256–262. doi: 10.1213/01.ane.0000265552.43299.2b Capdevila, X., Pirat, P., Bringuier, S., Gaertner, E., Singelyn, F., Bernard, N., … Bonnet, F. French Study Group on Continuous Peripheral Nerve Blocks . ( 2005 ). Continuous peripheral nerve blocks in hospital wards after orthopedic surgery: A multicenter prospective analysis of the quality of postoperative analgesia and complications in 1,416 patients. Anesthesiology, 103(5), 1035–1045. Centers for Disease Control and Prevention and The Arthritis Foundation. (2010). A national public health agenda for osteoarthritis 2010. Retrieved from http:// www.cdc.gov/arthritis/docs/Oagenda.pdf Centers for Disease Control and Prevention and The National Center for Health Statistics. (2010). Health, United States, 2010 with special features on death and dying. Retrieved from http://www.cdc.gov/nchs/data/ hus/hus10.pdf Chelly, J. E., Greger, J., Gebhard, R., Coupe, K., Clyburn, T. A., Buckle, R., & Criswell, A. (2001). Continuous femoral blocks improve recovery and outcome of patients undergoing total knee arthroplasty. The Journal of Arthroplasty, 16 ( 4 ), 436 – 445 . doi:10.1054/arth .2001.23622 DeLoach, L., Higgins, M., Caplan, A., & Stiff, J. (1998). The visual analog scale in the immediate postoperative period: Intrasubject variability and correlation with a numeric scale. Anesthesia & Analgesia, 86(1), 102–106. DeRuyter, M., Brueilly, K., Harrison, B., Greengrass, R., Putzke, J., & Broderson, M. (2006). A pilot study on continuous femoral perineural catheter for analgesia after total knee arthroplasty: The effect on physical rehabilitation and outcomes. The Journal of Arthroplasty, 21(8), 1111–1117. doi:10.1016/j.arth.2005.12.005 Gallagher, E., Liebman, M., & Bijur, P. (2001). Prospective validation of clinically important changes in pain severity measured on a visual analog scale. Annals of Emergency Medicine, 38(6), 633–638. Ilfeld, B. M., & Enneking, F. K. (2005). Continuous peripheral nerve blocks for patients at home. American Society of Anesthesiologists Newsletter, 69(5), 10–11. Ilfeld, B. M., Le, L. T., Meyer, S., Mariano, E. R., Vandenborne, K., Deuncan, P. W., . . . Gearen, P. F. (2008). Ambulatory continuous femoral nerve blocks decrease time to discharge readiness after tricompartment TKA . Anesthesiology , 108 ( 4 ), 703 – 713 . doi:10.1097/ALN.0b013e318167af46 Ilfeld, B. M., Wright, T., Enneking, F. K., & Morey, T. (2005). Joint range of motion after total shoulder arthroplasty with and without a continuous interscalene nerve block: A retrospective, case–control study. Regional Anesthesia & Pain Medicine, 30(5), 429–433. Ipswich, M. A., Woods, G., O’Connor, D., & Calder, C. (2006). Continuous femoral nerve block versus intraarticular injection for pain control after anterior cruciate ligament reconstruction. American Journal of Sports Medicine, 34(8), 1328–1333. Layzcll, M. (2007). Pain management: Setting up a nurseled femoral nerve block service. British Journal of Nursing, 16(12), 702–705. Mehrkens, H., & Geiger, M. (2005). Peripheral regional anesthesia: Tutorial from the Ulm Rehabilitation Hospital (3rd ed., pp. 34–36). Ulm, Germany. Retrieved from http://www.nerveblocks.net/_static/c/ DOWNLOAD/RKU-english/pdf/RKU_english.pdf

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