Total shoulder arthroplasty (TSA) results in severe postoperative pain that traditionally requires hospital admission to provide potent analgesia with IV opioids for both baseline pain and to enable effective rehabilitation (1–4). Perineural infusion or a continuous nerve block does not always require hospitalization (5), and provides site-specific analgesia with minor, if any, side effects (6,7). Portable infusion pumps have been used to improve analgesia for outpatients after mild and moderately painful ambulatory shoulder surgery (7–11). This pilot study was designed to evaluate the feasibility of converting TSA into an ambulatory procedure using perineural interscalene local anesthetic infusion and portable infusion pumps.
The investigation was divided into two phases: the Hospitalized phase allowed for patient discharge as early as the day after surgery, postoperative day (POD) 1, whereas the Ambulatory phase allowed for discharge home directly from the postanesthesia care unit (PACU). The Hospitalized phase was prospectively designated to conclude after 5 patients had met all discharge criteria (Table 1) both in the PACU and POD 1, and subsequently completed their infusion successfully at home. Successful infusion was defined for both phases as a patient 1) receiving acceptable analgesia as measured using a numeric rating pain scale (NRS <4; scale of 0–10, 0 = no pain, 10 = worst imaginable pain) throughout POD 7 (12); 2) avoiding hospital readmission; and 3) achieving at least 50% of the surgeon’s shoulder elevation and external rotation goals (defined below) in the PACU and on POD 3. The Ambulatory phase was designated to conclude after successful completion of 5, of a maximum of 10, patients.
After IRB approval, we prospectively enrolled patients scheduled for unilateral TSA. Subjects were required to 1) live within 2 h of the hospital; and 2) have a caretaker who would remain with them during the local anesthetic infusion and could return them to the hospital if necessary. Exclusion criteria included any contraindication to interscalene nerve block, any known heart or lung disease, baseline Spo2 <96%, a history of opioid dependence or current chronic analgesic therapy, allergy to study medications, known hepatic or renal insufficiency, peripheral neuropathy, and morbid obesity (body mass index >40 kg/m2).
After written, informed consent, interscalene catheters (StimuCath; Arrow International, Reading, PA) were placed using a technique described previously (8). Forty milliliters of ropivacaine, 0.2%, with epinephrine, 100 μg, was injected via the catheter with gentle aspiration every 3–5 mL. For the surgical procedure, patients received a standardized general anesthetic without opioids.
Postoperatively, a perineural bolus was administered for an NRS >3 (20 mL of ropivacaine, 0.2%, with epinephrine, 50 μg), and an electronic, portable infusion pump (CADD-Legacy PCA; Smiths Medical, St. Paul, MN) with a 600-mL reservoir of ropivacaine, 0.2%, was attached to the catheter (basal rate = 7 mL/h, bolus = 3 mL, lockout = 60 min) (13). Patients received scheduled celecoxib, 100 mg twice daily, and acetaminophen, 975 mg every 6 h. Rescue opioid and route of administration were determined by pain severity: oral oxycodone 5 mg (NRS <4), oral oxycodone 10 mg (NRS = 4–5), or IV morphine 2–4 mg (NRS >5). The patient and caretaker were given verbal and written instructions on the use of the pump and catheter along with physician telephone and pager numbers.
In the PACU, both patients and their caretakers received instruction on rehabilitation exercises by a physical therapist. The primary indicator of functional outcome after TSA is range-of-motion (14). For the first 2–6 wk after surgery, patients undergo passive elevation and external rotation up to surgeon-defined maximums, or goals, to avoid damaging the rotator cuff (3,15). Prospectively determined discharge criteria (Table 1) were subsequently evaluated and patients discharged to the hospital’s General Clinical Research Center (GCRC), and then home the following morning if they again met criteria for discharge.
Patients were telephoned beginning the night of surgery, and each evening thereafter through the night after catheter removal. On POD 3, patients returned to the GCRC to have their catheter site examined, local anesthetic reservoir replenished, and undergo a rehabilitation session with a physical therapist. In the evening of POD 6, patients’ caretakers removed the catheters using a pair of nonsterile gloves, with a physician in telephone contact throughout.
One change was made to the protocol after the completion of the Hospitalized phase: upon arrival in the PACU, the perineural bolus (20 mL of ropivacaine, 0.2%, with epinephrine, 50 μg) was administered for an NRS >0 instead of an NRS >3.
Eight patients were enrolled in this phase and had an interscalene catheter placed successfully (Table 2). One subject was erroneously included in the study (exclusion criteria: asthma), and was removed from the investigation. Five patients (63%) met all discharge criteria both in the PACU and on POD 1, and were discharged home on POD 1. Two patients (25%) did not meet discharge criteria in the PACU. The first because of an NRS = 7 that required 4 mg of IV morphine. This patient met discharge criteria the following morning and was discharged home on POD 1. The second patient had an estimated blood loss of 2400 mL (Table 1), and was discharged home on POD 2.
For all patients, pain was well controlled with <5 mg of IV morphine (Fig. 1, Table 3). Postoperative oral opioid requirements and sleep disturbances were minimal (Table 3). All patients reached at least 50% of the surgeon-defined range-of-motion goals (Table 3). All subjects underwent successful perineural infusion at home until their catheters were inadvertently dislodged (n = 1, POD 4) or removed (n = 6, POD 6).
Six patients were enrolled in this phase, all had an interscalene catheter placed successfully, and all met discharge criteria in the recovery room after surgery (Table 2). However, one patient was admitted overnight secondary to operating room delays resulting in surgery completion in the late evening. The remaining 5 patients were discharged directly from the recovery room. All 6 patients underwent successful ambulatory perineural infusion for 4–6 days. Postoperative pain was well controlled (Fig. 1), oral opioid requirements and sleep disturbances were minimal, range-of-motion consistently reached at least 50% of the surgeon-defined goals, and patient satisfaction was high (Table 3). All subjects underwent successful perineural infusion at home until their catheters were inadvertently dislodged (n = 1, POD 4) or removed (n = 5, POD 6).
There were no pump malfunctions or alarms and caretakers for patients in both groups reported no difficulty removing catheters at home.
For the patients of this pilot study who underwent TSA and ambulatory perineural local anesthetic infusion, postoperative pain was well controlled with baseline and breakthrough pain intensity below levels previously reported for much smaller ambulatory orthopedic procedures (16). Patients also achieved >50% of the surgeon-defined maximal elevation and external rotation without exception, and often reached 100% of this goal. This degree of comfort and shoulder mobility was achieved with minimal oral opioid requirements and sleep disturbances, leading to a very high rate of patient satisfaction.
Although this evidence demonstrates that TSA may be performed in the ambulatory environment, it does not define the appropriate subset of patients and incidence of complications associated with this practice (e.g., local anesthetic toxicity or infection). Additional research is required to define the appropriate subset of patients and determine the complication incidence associated with this practice before its mainstream use.
The authors gratefully acknowledge the invaluable assistance of the staff of both the Regional Anesthesia Block Room and General Clinical Research Center, including Doug Theriaque, MS, for figure compilation.
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© 2005 International Anesthesia Research Society
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