Cost-minimization

  Cost-benefit analysis

  Cost-effectiveness analysis

  Cost-utility analysis

        CEA is applicable when the effects of comparable health treatments or services share the same therapeutic goals, but have different degrees of effectiveness.⁴ With CEA, the analyst can compare alternative treatment strategies so that results can be expressed in identical effectiveness units. CEA accounts for the effect of a treatment plan on all clinical outcomes and its economic implications, rather than considering only the cost of devices, supplies, and pharmaceuticals.⁴ Effectiveness indicators, such as the number of adverse effects avoided or hospital stay reductions, are useful for comparing the different therapeutic alternatives considered. For this reason, CEA is one way of comparing treatment plans with the same desired effect but different outcome profiles, thus producing results expressed in terms of the number of adverse effects avoided. This approach implies weighting all adverse effects alike, or weighting the different adverse effects in the way deemed most suitable by the analyst.⁴

        With respect to anesthesia selection, it is highly unlikely that comparing regional (RA) with general anesthesia/ volatile agent (GAVA) techniques would show equal benefits or equal effectiveness (ie, life-years gained, days of disability avoided). RA significantly differs from GAVA, and the relevant side effect profiles and risks are quite different as well. In fact, in the past few years, it has become very clear in ambulatory procedures, for example, that the choices of the anesthetic and postoperative analgesic techniques have significant consequences on both the length of hospital stay and the frequency of unplanned hospitalization,^5,6 and consequently, the overall cost of the surgery. As a result, comparisons between RA and GAVA would require a cost-benefit, cost-utility, or cost-effectiveness analysis.

        As physicians caring for individual patients, it is important to note that basing a clinical practice strictly on cost analysis is not well advised, since individual patients have individual needs. However, in the setting of identifiable patient and hospital benefits when RA is used instead of GAVA, proper patient education regarding the benefits of RA is a most necessary step before any patient or health system benefits can be enjoyed.

        It is also important to note that the literature is not replete with conclusive evidence addressing cost-effectiveness of RA versus GAVA for surgical procedures in which both options are viable alternatives for patient care. Limited studies available can be used to apply cost analysis estimations for other studies that did not specifically address costs, but such approaches must be interpreted with caution.

       ANESTHESIOLOGY INTERVENTIONS APPLIED TO COST ANALYSES

Selection of Techniques, Drugs, & Agents

Rationale for Avoiding General Anesthesia with Volatile Agents in Outpatients

When considering invasive outpatient orthopedic surgery, the routine use of GAVA without peripheral nerve blocks as the centerpiece of a multimodal analgesic plan is commonly associated with the following costly outcomes: (1) postanesthesia care unit (PACU) admission; (2) multiple nursing interventions for pain and postoperative nausea or vomiting (PONV); (3) PACU and same-day surgery discharge delays; and (4) unplanned hospital admission.^6–8 However, most hospital pharmacy and therapeutics committees are primarily focused on the pharmacy budget. Six percent or less of all hospital costs related to surgical care are attributed to pharmacy drug costs, and examining drug costs in isolation without regard to patient outcomes is ill-advised. The “least expensive” outpatient GAVA technique, from the standpoint of drug acquisition for line items used for anesthesia induction and maintenance, would probably include thiopental, succinylcholine, opioids and volatile agents.

Postoperative Nausea & Vomiting & Comprehensive Multimodal Analgesia in Outpatient Regional Anesthesia Practice

Clinical Pearls

A traditional GAVA plan (thiopental, succinylcholine, volatile agents, and opioids) is traditionally favored for these specific line-item budgets of the anesthesia department and the hospital pharmacy, but the technique is fraught with “downstream” expenses for the hospital and presents a common basis for patient dissatisfaction. It has been well documented that GA techniques that exclusively use propofol for induction and maintenance (or as an intravenous sedative technique combined with RA) has a significantly lower PONV rate than do GAVA techniques,^10,13,14 and volatile agents and opioids are considered to be the leading causes of PONV.¹⁵ Exclusive use of propofol instead of volatile agents is considered to provide an important but incomplete method of prevention of PONV.¹⁵ Three antiemetics of differing mechanisms are required to prevent equivalent PONV outcomes in GAVA patients versus propofol total intravenous technique patients.¹⁶ RA techniques (without GA) are historically considered to be protective against PONV,¹⁷ but recent research has indicated that there can be significant differences in PONV incidence when differing RA techniques are compared for the same type of surgical procedure.¹⁸ In fact, patients undergoing single-injection peripheral nerve block (PNB) techniques that are later prescribed intravenous patient-controlled analgesia (IVPCA) do not appear to have significant benefit of PONV prevention versus similar patients undergoing GAVA with IVPCA,¹⁷ whereas patients receiving sustained analgesia primarily with continuous PNBs obtain additional PONV prevention benefits.¹⁷

        For simple knee arthroscopy (mean procedure time <30 min), GA with desflurane was compared with ipsilateral hyperbaric bupivacaine spinal anesthesia (4 mg) to assess PONV and a myriad of other outcomes.¹⁹ Desflurane patients received PONV prophylaxis with dexamethasone and ondansetron if at least two risk factors were present ( female, nonsmoker, PONV history, or motion sickness). Despite PONV prophylaxis in at-risk desflurane patients, all desflurane patients encountered significantly more PONV (6/32, 19%) than did selective spinal anesthesia patients (zero PONV, p = 0.024).¹⁹ In addition, desflurane patients encountered significantly more pain in both phases of postoperative recovery and more “extreme tiredness” in phase II recovery than did patients receiving selective spinal anesthesia.¹⁹

        Generally speaking, for outpatient orthopedic anesthesia routinely incorporating RA techniques: (1) GAVA should be avoided; (2) opioids should be minimized; and (3) at least two if not three antiemetics of differing mechanisms of antiemetic prophylaxis should be used. My suggested criteria for multimodal antiemetics in outpatient orthopedics are: (1) if the surgery duration is greater than 30 min; (2) if it is likely that opioids will be included in the postoperative anesthesia plan; (3) if intraarticular analgesic adjuncts are used that may increase PONV risk (eg, opioids, neostigmine); or (4) if GAVA is to be used. In outpatient orthopedics, use of a volatile agent alone is a sufficient sole risk factor for routine multimodal antiemetic prophylaxis, regardless of other risk factors. I suggest (1) oral perphenazine^18,20,21 (8 mg preoperatively, with consideration of a repeat 4-mg oral dose postoperatively should breakthrough PONV symptoms occur, but avoided in patients with Parkinson disease or history of adverse extrapyramidal reactions to phenothiazines); (2) dexamethasone^18,22–26 (4 mg intravenously, perhaps avoided in diabetic patients); and (3) a 5-HT₃ serotoninergic antagonist. The combination of dexamethasone and a 5-HT3 antagonist is more effective in preventing nausea and vomiting after discharge than is a 5-HT₃ antagonist used alone.²⁷

        It should be understood that opioids are commonly going to be used for RA procedure premedication, intraoperative management of nerve block onset latency, and postoperative analgesic rescue of symptomatic pain not covered by the peripheral block’s nerve distribution. In addition, multimodal analgesic techniques, such as low-dose intravenous ketamine,^28–31 pre- and postoperative inhibitors of the cyclooxygenase type-2 enzyme,^32–35 and intraarticular injections by the surgeon to cover myriad mechanisms of the acute pain inflammatory cascade, also have the potential to be useful.^36–42 As of this writing, the United States Food and Drug Administration has issued advisories regarding celecoxib and valdecoxib, while rofecoxib and valdecoxib have already been withdrawn from the market by manufacturers, due to an increase of cardiovascular adverse events associated with long-term use, so caution is advised pending final regulatory declarations.

Minimizing Anesthesia-Controlled Time in the Operating Room

Clinical Pearls

        The potential value of the RA induction room should not be underestimated from the pharmacoeconomic perspective. Performing PNB techniques before OR entry has been shown to be associated with a time savings of approximately 9 min of OR time per case compared with using GAVA without blocks.⁹ In general, when the patient enters the OR ready for surgical preparation, and has a faster emergence (and exit) due to the use of sedation versus GAVA, an OR with five cases can save 45 min/day. If the cost of a minute of OR time is estimated to be $30, then 1 day of this amount of time savings for five cases carries a potential cost reduction of $ 1350. A portion of this theoretical savings is likely “real” in centers operating at or above 80% capacity, in which forced overtime (of preoperative, intraoperative, and postoperative nursing/ancillary staff) is a major budgetary expenditure. The cost savings becomes even more significant when cases later in the day (eg, after 3 pm or 5 pm) are commonly “stacked” into fewer available staffed ORs, further lengthening already-long clinical days. Dexter and colleagues estimated that emergence which is 6 min faster than baseline likely translates to a per-case overtime reduction ranging from 1.3 to 2.6 min.⁴³ In a 50-case surgical pavilion, this translates to 65 to 130 min of overtime saved. How the reduction of anesthesia-controlled time influences OR staff retention is unknown. Repeated episodes of forced overtime for OR staff may lead to a loss of staff morale, which may translate to staff turnover. Staff turnover implies the replacement of departed, experienced staff with less experienced staff, associated training, and possible surgical process inefficiencies until training is complete and posttraining experience is sufficient to resume an optimally efficient surgical process. Prolonged anesthesia-controlled time may also adversely affect staff morale in both phase 1 and phase 2 PACUs. No studies to date have correlated reduced anesthesia-controlled time and perioperative nursing or OR staff retention.

        OR time savings for outpatient shoulder surgery, via shorter induction time and emergence time values has also been substantiated when interscalene nerve block was used alone without GAVA. In this study, recovery room times and unplanned hospital admissions were also reduced in the patients treated with the interscalene block versus GAVA.⁴⁴

Bypass of the Postanesthesia Care Unit in Ambulatory Surgery

Clinical Pearls

In outpatient surgery, PACU bypass has been shown to be achievable in nearly 90% of patients receiving exclusively RA techniques (including neuraxial techniques if hemodynamic criteria are met).¹⁰ To achieve PACU bypass in an institution where RA techniques are used in high volume, it is important to use tested criteria that incorporate both physiologic parameters and immediate symptomatic outcomes to determine PACU bypass eligibility and to use criteria that incorporate specific outcomes for both RA patients and GA patients.⁴⁵ Criteria that incorporate the original Regional Anesthesia PACU Bypass Criteria,¹⁰ the traditional Modified Aldrete Score,⁴⁶ the White-Song Fast-Tracking Criteria,⁴⁷ and the Mayo Modified Discharge Scoring System have been recently proposed (Table 74–1).^45,48

        In surgical pavilions with large caseloads (eg, 50 cases/day), an 80% PACU bypass rate (compared with no PACU bypass) can lead to a PACU nurse full-time equivalent (FTE) staffing reduction of up to four FTE if the PACU nurses are full-time employees, or by 20 nursing hours if the PACU nurses are part-time employees.43 When combined with forced overtime of OR staff and step-down recovery staff, OR time savings and PACU bypass (documented to be achievable with exclusive use of RA) can present important cost-saving opportunities for the hospital.

        In a patient population undergoing anterior cruciate ligament (ACL) reconstruction, PACU bypass is associated with hospital cost reduction of $420.⁴⁹ The cost savings component from the initial of $420 per PACU bypass patient (which excluded savings associated with nurse staffing reductions highlighted by Dexter and colleagues detailed earlier) were likely attributable to RA patients experiencing fewer symptoms than those receiving GAVA. Williams and coworkers also reported that throughout the multipavilion university hospital during peak use of PACU bypass (3000 outpatient orthopedics procedures per year), PACU nurse staffing requirements for 25,000 surgical patients per year (throughout all pavilions) consisted of 28 FTE PACU nurses.⁴⁹ When the main campus multipavilion hospital relocated outpatient orthopedics to another off-site hospital in the health system, PACU bypass was used on the main campus for monitored anesthesia care cases only. Soon after, PACU nurse staffing requirements increased to 36 FTE for the same annual caseload.⁴⁹ PACU bypass should not be underestimated as a potentially powerful cost management tool in ambulatory orthopedic anesthesia when nerve blocks are routinely used, not only from a staffing standpoint, but also with respect to overall symptom reduction and return to wakefulness during same-day recovery.

Successful Same-Day Discharge in Ambulatory Surgery

Clinical Pearls

        Woolhandler and Himmelstein have estimated that the cost of hospital admission (for all types of diagnoses and procedures) is $1050.⁵⁰ Williams and coworkers found that the hospital cost increment associated with an overnight admission after ACL reconstruction was $385.⁴⁹ The likely cost differences in the findings of Williams and coworkers versus those of Woolhandler and Himmelstein are likely related to the generally healthy status of outpatients presenting for ACL reconstruction. The key point is that it will always be less expensive for a patient to go home immediately after outpatient surgery than to be admitted overnight for observation.⁵¹ That said, precautions are required to ensure that costs are not incurred later in the form of requiring hospital readmission for complications improperly managed during the initial admission, especially since these readmissions are often ineligible for third-party reimbursement. Indeed, refractory pain is the most common cause of hospital readmission after discharge, accounting for over one third of such readmissions.⁵²

Adapted, with permission, from Williams BA: For outpatients, does regional anesthesia truly shorten the hospital stay, and how should we define postanesthesia care unit bypass eligibility? Anesthesiology 2004; 101:3.

^a Reference 10; ^b Reference 66; ^cReference 46; ^d Reference 47; ^e Reference 48.

        It is important to understand that the associated hospital cost reductions of $420 for PACU bypass and $385 for successful same-day discharge were calculated by using standard econometric techniques of multivariate regression analysis.⁴⁹ Thus, the associated cost savings captured in these values incorporate any and all expenditures related to OR time, additional RA equipment and medications used, prophylactic antiemetics, and postoperative parenteral nursing interventions required for symptoms. When specific time-resource and symptomatic outcomes were incorporated into the stated multivariate regression analysis, these covariates were not independent predictors of hospital costs, only PACU bypass and successful same-day discharge were independent predictors of hospital cost reductions. Thus, when deriving any cost analysis equation using these cost-saving values, it is important to use these values only for such analyses, pending the results of future, more detailed, economic studies. It would not be methodologically correct to simultaneously incorporate cost values from myriad other studies that calculate various itemized costs of events such as “minutes of PACU time,” “minutes of phase 2 recovery time,” or individual drug costs or labor costs. The use of cost estimate values from multiple studies is methodologically incorrect since “double-counting” would occur, which may artificially elevate incremental differences in cost, cost-benefit, cost-effectiveness, and cost-utility.

Successful Resource Management of Well-Trained RA Practitioners in the Ambulatory Surgery Setting

Clinical Pearls

        In ambulatory surgery, well-trained RA practitioners may be tempted to implement a comprehensive nerve block care algorithm for all surgical patients. This enthusiasm should be tempered by the consideration of the “opportunity cost” of providing labor-intensive nerve block anesthesia for patients who may not necessarily benefit from these procedures. For instance, in the study by Williams and colleagues,¹¹ 543 patients underwent “relatively noninvasive” outpatient knee surgery, while the remainder underwent “more invasive” knee surgery. Forty-three riercenf (253/543) of the patients undergoing the noninvasive procedure received femoral (with or without sciatic) nerve blocks, but the use of nerve blocks in these patients was not associated with a reduction in symptoms, nursing interventions, or unplanned hospital admissions.¹¹ As a result, these authors concluded that based on this retrospective review of a significant clinical caseload of noninvasive knee surgery outpatients, nerve blocks should be reserved for patients who have significant refractory postoperative pain, or in other special situations such as a complicated pain history or intolerance to traditional oral analgesic techniques.

        In the same review of 1200 consecutive knee surgery outpatients, 657 underwent more invasive knee surgery, and 527 of these 657 (80%) received femoral with or without sciatic nerve blocks.¹¹ In these patients, nerve block anesthesia and analgesia were significantly associated with reduced pain symptoms during recovery (therefore, fewer nursing interventions for pain management), and fewer unplanned hospital admissions. It is important to note that the selection of nerve block anesthesia-analgesia appears to be necessary but not sufficient to comprehensively reduce postoperative nursing interventions and unplanned hospital admissions: whenever GAVA was used (in the presence or the absence of nerve block anesthesia), the odds ratio of more associated symptoms after GAVA was 2.1 (p < 0.001), whereas the odds ratio of more associated unplanned hospital admissions after GAVA was 3.3 (p = 0.001).¹¹ Thus, nerve block anesthesia and analgesia for indicated (more invasive) procedures (ideally in the setting of a comprehensive multimodal analgesic care plan) and the avoidance of GAVA (for all procedures) will likely provide the anesthesia care team (and the hospital) with the fewest possible side effects and the greatest facilitation of successful same-day discharge. However, routine nerve blocks for noninvasive knee surgery may be an investment of RA practitioners’ time (and risk) that may provide relatively little benefit, and that takes away opportunity for RA practitioners to engage in other value-adding activities. Such value-adding activity may include the placement of continuous nerve block catheters for select patients, when time may have been only available previously to administer a single-injection nerve block.

Pain Risk Stratification

Upper Extremity Surgery

Clinical Pearls

        For outpatient shoulder or upper extremity surgery, there have been few substantiated, comprehensive recommendations for allocating nerve blocks (single-injection vs continuous infusion) based on anticipated postoperative pain, postoperative nursing interventions (with versus without), or unplanned hospital admissions.

        In shoulder surgery, the comparison of single-injection blocks with GAVA has shown predictable findings. For arthroscopic acromioplasty of the shoulder performed under GAVA, Singelyn and colleagues showed that interscalene nerve block provided definitive recovery advantages over suprascapular nerve block, single-injection intraarticular local anesthetic, and controls.⁵³ For outpatient open surgery of the rotator cuff, Hadzic and coworkers reported that GAVA use (vs single-injection brachial plexus block with ropivacaine) led to increased postanesthesia care unit admissions (vs phase 1 recovery bypass), higher reports of postoperative pain, longer time to ambulation, longer time to same-day discharge, and higher risk of unplanned hospital admission.⁵⁴ In this study, no outcome differences occurred in follow-up from 24 h to 2 weeks after surgery, but this study was underpowered.

        In a recent review, Boezaart suggested that an anterior approach to the brachial plexus is ideal for open-shoulder surgery, whereas a posterior (paravertebral) approach is well suited for arthroscopic surgery.⁵⁵ In this review, Boezaart explains that the anterior approach to the brachial plexus concomitantly provides reliable anesthesia to the overlying skin, but the posterior approach does not. Potential advantages to the posterior approach may include less frequent blockade of the phrenic nerve, but the posterior approach is also associated with less motor block. Arthroscopic shoulder surgery using the posterior approach, most commonly, must be accompanied by general anesthesia,⁵⁵ in order to provide sufficient analgesia to the overlying skin.

        In two recent, separate studies of the efficacy of intraarticular analgesic infusions, some conclusions can be drawn regarding pain risk stratification in common outpatient shoulder procedures. One study by Harvey and associates showed that patients undergoing arthroscopic subacromial decompression of the shoulder receiving ropivacaine 0.2% in a continuous subacromial infusion experienced 34% lower pain scores than did saline controls.⁵⁶ Another study by Boss and coworkers⁵⁷ showed that patients receiving a continuous subacromial infusion of bupivacaine 0.25% after open acromioplasty and rotator cuff repair did not experience any difference in pain relief from those receiving saline placebo infusion. In one study by Klein and colleagues, patients undergoing open rotator cuff repair with an active treatment of local anesthetic infusion via an indwelling interscalene catheter had significantly improved pain management than did control patients receiving a saline placebo infusion.⁵⁸ Thus, the logical conclusion can be reached that open acromioplasty and rotator cuff repair likely creates more postoperative pain than does arthroscopic subacromial decompression, based on the lack of responsiveness of the former (more invasive) procedure to subacromial infusion analgesia, whereas the less invasive procedure is responsive to subacromial infusion analgesia. However, open rotator cuff repair patients have favorable analgesic responses when a continuous interscalene catheter with local anesthetics is used.

        A review by Chelly and associates ² provides an overview that may guide practitioners for categories of postoperative shoulder pain, until more definitive evidence is available. In this review, shoulder procedures are clustered into a catheter-eligible category if the following procedures are involved: shoulder arthroplasty, rotator cuff repair, Bankart repair, and open reduction/internal fixation of the humerus. The benefit of continuous interscalene catheters for shoulder arthroplasty and rotator cuff repair is well documented.^58,60–65 Although logic would indicate similar effectiveness for less invasive procedures, there is little evidence at this time to indicate that interscalene brachial plexus catheters would be similarly useful for patients undergoing less invasive shoulder operations such as shoulder stabilization procedures, distal clavicle resection or acromioplasty, subacromial decompression, biceps tenodesis or tenotomy, or even routine debridement inside the glenohumeral joint, when compared with single-injection nerve blocks and perioperative multimodal oral analgesia. Thus, studies are needed to show the benefit of continuous nerve blocks (vs singleinjection), and single-injection blocks (vs no blocks) for a wide variety of shoulder procedures that produce an uncertain magnitude of postoperative pain.

        For outpatient wrist and hand surgery, Hadzic and coworkers addressed this patient population comparing chloroprocaine infraclavicular nerve block with GAVA, showing that GAVA use led to increased postanesthesia care unit admissions (vs phase 1 recovery bypass), higher reports of postoperative pain, longer time to ambulation, and longer time to same-day discharge.⁶⁶ However, there were no outcome differences in follow-up from 24 h to 2 weeks after surgery. This latter finding was underpowered and did not show statistical equivalence.⁶⁶ Chan and associates prospectively studied nonrandomized hand surgery patients (n = 126) undergoing either GAVA (n = 39), axillary block (n = 42), or Bier block (n = 45).⁶⁷ GAVA was associated with the most postoperative symptoms and nursing labor intensity, as well as the longest discharge times. Bier block patients had the fastest recovery times and lowest associated total perioperative costs, but also were at small risk for conversion of the anesthesia plan (2/45) to GAVA due to tourniquet pain. Gebhard and colleagues retrospectively studied hand surgery patients ( n = 62) receiving GAVA ( n = 20), Bier block (n = 21) or wrist block (n = 21).⁶⁸ They found that wrist block patients were discharged home soonest, and encountered (1) less hypertension than did Bier block patients; and (2) less hypotension than did GAVA patients.⁶⁸ McCartney and coworkers prospectively studied 100 hand surgery outpatients randomized to receive GAVA (n = 50) or brachial plexus block with lidocaine (n = 50). These authors found essentially similar if not identical findings to those reported by Hadzic (prospectively) and Chan (retrospectively) as mentioned earlier. McCartney and coworkers also concluded that there were no long-term (2-week) pain outcome differences, although the brachial plexus block group only received the short-acting local anesthetic lidocaine.⁶⁹

        For other (distal) upper extremity surgery, Chelly and associates state that PNB catheters are likely indicated for implantation procedures after trauma, as well as for open reduction/internal fixation of the hand or digits,⁵⁹ although a prospective randomized trial to definitively verify this intuitive concept may be difficult to achieve. Ilfeld and colleagues have shown that a continuous infraclavicular brachial plexus catheter (vs placebo catheter infusion) resulted in less postoperative dynamic pain and opioid consumption and fewer, sleep disturbances.⁷⁰ The surgical procedures performed included open reduction/internal fixation (elbow, radius, or ulna), bony/capsular wrist procedures (carpectomy, capsulodesis, fusion, or shrinkage) metacarpal arthroplasty, suspensionplasty, and ulnar nerve transposition. Although all of these procedures are intuitively painful, the small study sample size (30 patients divided equally between two groups) prevents the practitioner from distinguishing relative postoperative pain scores per procedure.⁷⁰

        Less invasive upper extremity procedures (typically applicable to outpatients) have not been comprehensively studied with respect to potential the value of continuous catheters versus single-injection blocks. However, Rawal and coworkers⁷¹ showed that an axillary continuous nerve block catheter with intermittent bolus dosing provided excellent wrist and hand analgesia for patients undergoing surgical procedures that may have been somewhat less invasive than those described earlier by Ilfeld and colleagues.⁷⁰ Rawal and coworkers’ study included 60 patients who received a mepivacaine axillary block bolus and concomitant nerve block catheter placement and were undergoing carpal tunnel release (h = 11), finger fracture repair (n = 11), tendon repair (n= 10), finger joint arthrodesis (n = 10), wrist arthroscopy (n = 8), and tumor resection or other procedures (n = 10). This study neither studied a control group of patients undergoing no nerve block, nor a treatment group undergoing single-injection nerve block only. In fact, 3 of the 60 patients studied did not use the bolus dose function postoperatively. However, most every bolus treatment was prompted by patients achieving a verbal pain score of at least 5 (out of 10), and bolus treatments returned pain scores to around 3 (out of 10), thus providing clinically significant analgesia.⁷¹ Patients in this study used all of their allotted boluses by the twelfth hour after surgery; as such, the reader may speculate that patients may simply benefit from a long-acting single-injection nerve block designed to provide 18 h of postoperative analgesia, instead of the technical complexity of a nerve block catheter. Rawal and coworkers found that the most common cause of patient dissatisfaction with the continuous catheter, intermittent-bolus technique was hand numbness.⁷¹ Therefore, patient uncertainty and potential dissatisfaction associated with prominent numbness or motor block should likely be factored into the decision of which nerve block technique is selected when a single-injection versus a continuous catheter technique is considered.

        To summarize, outpatient hand surgery often results in significant postoperative pain, with patient pain scores often reaching or exceeding VAS 5 (out of 10).⁷² Retrospective reviews and prospective studies have demonstrated uniformly that patients receiving PNBs have significantly improved outcomes on the day of surgery compared with patients receiving GAVA. For shoulder surgery, the use of continuous brachial plexus catheters is sufficiently substantiated to recommend their routine placement (by trained practitioners) for invasive shoulder surgery. These findings also encourage the routine use (by trained practitioners) of all peripheral/regional techniques for upper extremity surgery, although further research is needed to determine outcome benefits of continuous versus single-injection nerve blocks in the days and weeks following mildly to moderately invasive shoulder and distal upper extremity surgery. The usefulness of intraarticular and incisional infusions after simple arthroscopic procedures of the shoulder has been documented, but these articular and incisional infusions do not appear to confer sufficient analgesia after more invasive, open, shoulder surgery.

Knee Surgery

Clinical Pearls

        Recommendations for rational nerve block selection (single-injection, vs continuous catheter, vs none) in outpatient knee surgery have been recently suggested.⁷³ This guideline incorporates the resource management principles described earlier, and creates three major categories: (1) noninvasive, (2) more invasive, and (3) most invasive (Table 74-2). Noninvasive implies that routine use of nerve block analgesia is probably not necessary, as described previously.¹¹ “More invasive” implies that a routine femoral nerve block would be recommended, but that a sciatic nerve block is probably not necessary, since the vast majority of the postoperative pain is likely attributable to the femoral nerve distribution. “Most invasive” implies that the postoperative pain will be likely attributable to both femoral and sciatic nerve distributions, and both nerves would likely benefit from routine blockade. The more invasive and most invasive knee surgery categories are based on clustering moderate and severe into one category of surgical invasiveness.¹¹ This algorithm⁷³ also describes when a single-injection block would likely be sufficient, vs when a continuous nerve block catheter would likely be of greater benefit than a single injection.

Related posts:

Regional Anesthesia in the Patient with Preexisting Neurologic Disease. The History of Local Anesthesia. Stimulating Catheters. Ultrasound-Assisted Nerve Blocks in Adults. Cutaneous Blocks for the Upper Extremity. Cervical Plexus Block.