Interscalene brachial plexus block for outpatient shoulder arthroplasty: Postoperative analgesia, patient satisfaction and complications.

BACKGROUND: Shoulder arthroplasty procedures are seldom performed on an ambulatory basis. Our objective was to examine postoperative analgesia, nausea and vomiting, patient satisfaction and complications of ambulatory shoulder arthroplasty performed using interscalene brachial plexus block (ISB). MATERIALS AND METHODS: We prospectively examined 82 consecutive patients undergoing total and hemi-shoulder arthroplasty under ISB. Eighty-nine per cent (n=73) of patients received a continuous ISB; 11% (n=9) received a single-injection ISB. The blocks were performed using a nerve stimulator technique. Thirty to 40 mL of 0.5% ropivacaine with 1:400,000 epinephrine was injected perineurally after appropriate muscle twitches were elicited at a current of less than 0.5% mA. Data were collected in the preoperative holding area, intraoperatively and postoperatively including the postanesthesia care unit (PACU), at 24h and at seven days. RESULTS: Mean postoperative pain scores at rest were 0.8 ± 2.3 in PACU (with movement, 0.9 ± 2.5), 2.5 ± 3.1 at 24h and 2.8 ± 2.1 at seven days. Mean postoperative nausea and vomiting (PONV) scores were 0.2 ± 1.2 in the PACU and 0.4 ± 1.4 at 24h. Satisfaction scores were 4.8 ± 0.6 and 4.8 ± 0.7, respectively, at 24h and seven days. Minimal complications were noted postoperatively at 30 days. CONCLUSIONS: Regional anesthesia offers sufficient analgesia during the hospital stay for shoulder arthroplasty procedures while adhering to high patient comfort and satisfaction, with low complications.

Combined lumbar-plexus and sciatic-nerve blocks: an analysis of plasma ropivacaine concentrations.

BACKGROUND AND OBJECTIVES: Lumbar-plexus and sciatic-nerve blocks are commonly combined for lower-extremity anesthesia using large doses of ropivacaine. Limited information is available about the pharmacokinetics of this practice. We analyzed plasma ropivacaine concentrations after single-injection lumbar-plexus blocks with and without sciatic-nerve blocks. METHODS: Twenty patients having lower-extremity surgery using a lumbar-plexus block with 0.5% ropivacaine with 1:400,000 epinephrine (35 mL, n = 10) or the same lumbar-plexus block with the addition of a sciatic-nerve block (25 mL, n = 10, 60 mL total) using the same solution were enrolled. Venous blood samples were collected at 5, 15, 30, 45, 60, 120, and 240 minutes after block placement and analyzed for total ropivacaine concentration by use of gas chromatography. Individual timepoints, maximum concentrations (C(max)), and time to C(max) (T(max)) were compared. Values are mean +/- SD. RESULTS: Both groups demonstrated a rapid increase in plasma concentration over the first 30 to 45 minutes. Concentrations were greater for those who received both blocks (P = .0005) at all timepoints. The lumbar-plexus block C(max) was less (986 +/- 221 ng/mL) than for the combined blocks (1,560 +/- 351 ng/mL, P = .0004). The T(max) was greater for the lumbar plexus (80 +/- 49 min) than for the combined blocks (38 +/- 22 min, P = .03). There was no relationship between the C(max) and patient age, weight, or body mass index. CONCLUSIONS: The results of this study demonstrate that the plasma ropivacaine concentrations increase quicker when a sciatic-nerve block is added to a lumbar-plexus block, but C(max) remains below the toxicity threshold.

The effect of age on sciatic nerve block duration.

The physiologic changes that occur with advancing age and their effect on the duration of peripheral nerve blocks have yet to be defined. We prospectively studied the duration of sciatic nerve block using mepivacaine in younger and older patients. Eighty ASA physical status I-III patients, aged 18-35 (n = 40) or 55-80 (n = 40) yr, having outpatient knee arthroscopy with a femoral block and a standardized sciatic nerve block were enrolled; 37 in each group completed the study. All patients received a Labat sciatic nerve block using 20 mL of 1.0% mepivacaine with 0.1 mEq/mL sodium bicarbonate and 1:400,000 (2.5 microg/mL) epinephrine and a femoral nerve block. The duration of sensory block (sensation of pinprick, temperature, and vibration), motor block (plantar and dorsi flexion), and complete sensory and motor block in the sciatic nerve distribution of the operative extremity were measured. The time for complete return of both sensory and motor function was longer in the older group, 329 +/- 47 min compared with 306 +/- 46 min (mean +/- sd) in the younger group (P = 0.04). The difference was small under the conditions of this study and would not be perceived clinically. Age also increased the time to return of vibratory sensation (younger = 292 +/- 58 min, older = 257 +/- 50 min; P = 0.007). The other measurements did not differ between groups. We conclude that age may affect peripheral nerve blocks and that more investigation is needed to determine the pharmacologic, physiologic, and chronologic factors behind these findings.

Peripheral nerve block techniques for ambulatory surgery.

Peripheral nerve blocks (PNBs) have an increasingly important role in ambulatory anesthesia and have many characteristics of the ideal outpatient anesthetic: surgical anesthesia, prolonged postoperative analgesia, and facilitated discharge. Critically evaluating the potential benefits and supporting evidence is essential to appropriate technique selection. When PNBs are used for upper extremity procedures, there is consistent opioid sparing and fewer treatment-related side effects when compared with general anesthesia. This has been demonstrated in the immediate perioperative period but has not been extensively investigated after discharge. Lower extremity PNBs are particularly useful for procedures resulting in greater tissue trauma when the benefits of dense analgesia appear to be magnified, as evidenced by less hospital readmission. The majority of current studies do not support the concept that a patient will have difficulty coping with pain when their block resolves at home. Initial investigations of outpatient continuous peripheral nerve blocks demonstrate analgesic potential beyond that obtained with single-injection blocks and offer promise for extending the duration of postoperative analgesia. The encouraging results of these studies will have to be balanced with the resources needed to safely manage catheters at home. Despite supportive data for ambulatory PNBs, most studies have been either case series or relatively small prospective trials, with a narrow focus on analgesia, opioids, and immediate side effects. Ultimately, having larger prospective data with a broader focus on outcome benefits would be more persuasive for anesthesiologists to perform procedures that are still viewed by many as technically challenging.

Manuscript Architect: a Web application for scientific writing in virtual interdisciplinary groups.

BACKGROUND: Although scientific writing plays a central role in the communication of clinical research findings and consumes a significant amount of time from clinical researchers, few Web applications have been designed to systematically improve the writing process. This application had as its main objective the separation of the multiple tasks associated with scientific writing into smaller components. It was also aimed at providing a mechanism where sections of the manuscript (text blocks) could be assigned to different specialists. Manuscript Architect was built using Java language in conjunction with the classic lifecycle development method. The interface was designed for simplicity and economy of movements. Manuscripts are divided into multiple text blocks that can be assigned to different co-authors by the first author. Each text block contains notes to guide co-authors regarding the central focus of each text block, previous examples, and an additional field for translation when the initial text is written in a language different from the one used by the target journal. Usability was evaluated using formal usability tests and field observations. RESULTS: The application presented excellent usability and integration with the regular writing habits of experienced researchers. Workshops were developed to train novice researchers, presenting an accelerated learning curve. The application has been used in over 20 different scientific articles and grant proposals. CONCLUSION: The current version of Manuscript Architect has proven to be very useful in the writing of multiple scientific texts, suggesting that virtual writing by interdisciplinary groups is an effective manner of scientific writing when interdisciplinary work is required.

Peripheral nerve blocks and continuous catheter techniques.

Peripheral nerve blocks provide intense, site-specific analgesia and are associated with a lower incidence of side effects when compared with many other modalities of postoperative analgesia. Continuous catheter techniques further prolong these benefits. These advantages can facilitate a prompt recovery and discharge and achieve significant perioperative cost savings. This is of tremendous value in a modern health care system that stresses cost-effective use of resources and a continued shift toward shorter hospital stay as well as outpatient surgery.

Influence of obesity on surgical regional anesthesia in the ambulatory setting: an analysis of 9,038 blocks.

BACKGROUND: Regional anesthesia is increasing in popularity for ambulatory surgical procedures. Concomitantly, the prevalence of obesity in the United States population is increasing. The objective of the present investigation was to assess the impact of body mass index (BMI) on patient outcomes after ambulatory regional anesthesia. METHODS: This study was based on prospectively collected data including 9,038 blocks performed on 6,920 patients in a single ambulatory surgery center. Patients were categorized into three groups according to their BMI (<25 kg/m2, 25-29 kg/m2, > or =30 kg/m2). Block efficacy, rate of acute complications, postoperative pain (at rest and with movement), postoperative nausea and vomiting, rate of unscheduled hospital admissions, and overall patient satisfaction were assessed. Linear and logistic multivariable analyses were used to obtain the risk-adjusted effect of BMI on these outcomes. RESULTS: Of all patients 34.8% had a BMI <25 kg/m2, 34.0% were overweight (BMI 25-29 kg/m2), and 31.3% were obese (BMI > or = 30 kg/m2). Patients with BMI > or =30 kg/m2 were 1.62 times more likely to have a failed block (P = 0.04). The unadjusted rate of acute complications was higher in obese patients (P = 0.001). However, when compared with patients with a normal BMI, postoperative pain at rest, unanticipated admissions, and overall satisfaction were similar in overweight and obese patients. CONCLUSIONS: The present investigation shows that obesity is associated with higher block failure and complication rates in surgical regional anesthesia in the ambulatory setting. Nonetheless, the rate of successful blocks and overall satisfaction remained high in patients with increased BMI. Therefore, overweight and obese patients should not be excluded from regional anesthesia procedures in the ambulatory setting.

Increased body mass index and ASA physical status IV are risk factors for block failure in ambulatory surgery - an analysis of 9,342 blocks.

PURPOSE: Regional anesthesia can be the technique of choice for selected ambulatory surgery procedures, but in spite of its benefits, it has an inherent failure rate even in experienced hands. We examine the efficacy and factors associated with failure of ambulatory regional anesthesia techniques. METHODS: This study included 9,342 blocks performed on 7,160 patients at the Duke University Ambulatory Surgery Center. Blocks were classified as interscalene, supraclavicular, axillary, lumbar plexus, femoral, sciatic, ankle, paravertebral, spinal, and other (frequency less than 100). A block was considered surgical if a single attempt at placing the block resulted in a complete sensory, motor, and sympathetic nerve block. Multiple logistic regression analyses were used to assess the risk-adjusted association between patient characteristics and block failure. RESULTS: Paravertebral blocks and those considered in the "other" category had significantly higher failure rates (P < 0.001), while spinal and lumbar plexus blocks had lower than average rates of failure (P < 0.001 and P = 0.03, respectively). In multiple logistic regression analyses excluding paravertebral blocks, body mass index (BMI) scores greater than 25 (P values: BMI 25-29: < 0.001; BMI 30-34: P < 0.001; BMI 35: P < 0.001) and ASA physical status IV (P < 0.001) were significantly associated with higher block failure rates. CONCLUSION: High BMI and ASA IV are independent risk factors for block failure in ambulatory surgery patients.

In situ images of the thoracic paravertebral space.

BACKGROUND AND OBJECTIVES: In situ knowledge about the anatomic structures and the path of a needle percutaneously placed into the paravertebral space is an area that continues to be investigated. We describe an endoscopic technique that permits imaging of the contents and boundaries of the thoracic paravertebral space in cadavers. TECHNIQUE: A 43-year-old, 157-cm, 45-kg unembalmed female cadaver was placed in the prone position. Using a 2.3-mm diameter, 0 degree optical angle, fiberoptic ankle arthroscopy scope, trocar, introducer, and light source, thoracic paravertebral blocks were performed. To produce quality images, the trocar was advanced the length of the shaft, approximately 8 cm. The arthroscopy scope was then exchanged with the introducer. The trocar and arthroscopy scope were then gradually withdrawn posterior. RESULTS: Representative images that show the anatomic pathway of a needle as it would be directed into the paravertebral space as well as the boundaries of the thoracic paravertebral space were obtained. These included the costotransverse ligament, the spinal nerve, and the parietal and visceral pleura. CONCLUSIONS: The images help show the relationship of structures that are encountered during a paravertebral block. This new technique may be helpful in examining the spread of local anesthetic using dye or imaging the location of continuous catheters without having to dissect the insertion area.

Altered perceptions after upper and lower extremity blocks: an initial investigation.

BACKGROUND AND OBJECTIVES: Nerve blocks frequently produce unusual altered perceptions in the extremities. We examined perceptual changes experienced after peripheral blocks. METHODS: Fifty consecutive patients having an upper or lower extremity block for surgery participated in this prospective study. Patients were divided into 2 groups: upper extremity (n = 20) and lower extremity (n = 30). Each group was asked a list of questions about perceptions of limb sensation, length, weight, and location and given a detailed 2-point discrimination test over the V(1)-V(3) divisions of the trigeminal nerve prior to block and sedation. While the extremity was still blocked, the exam was repeated before postanesthesia care unit discharge. RESULTS: In both groups, 98% of patients described altered limb perception. The perceptions in the upper extremity were: heaviness, 60%; numbness, 50%; warmth, 40%; pain, 30%; full or fat, 20%; floating, 5%; shorter, 0%; or thinner, 10%. The perceptions in the lower extremity were: numbness, 75%; heaviness, 46%; warmth, 33%; pain, 32%; full or fat, 36%; floating, 25%; shorter, 18%, or thinner, 7%. Upper extremity block patients were more likely to describe the limb as lighter (P <.0001); the lower extremity group was more likely to describe the limb as numb (P =.01) or floating (P =.0002). There was no difference in the ability to correctly identify the location of the limb between the groups. There was no difference in 2-point discrimination between each assessment for either group. CONCLUSION: The results of this study confirm and quantify the perceptions experienced by patients undergoing upper and lower extremity blocks. These perceptions are prevalent. This knowledge is helpful in providing patients with accurate preoperative preparation. Further investigation is warranted to determine the neurologic etiology of these observations.

Continuous paravertebral catheter and outpatient infusion for breast surgery.

Paravertebral somatic nerve block (PVB) provides improved analgesia and decreased side effects compared with general anesthesia for breast surgery. The analgesia is limited with single injection PVB to the duration of the local anesthetic. Continuous paravertebral catheters and disposable home infusion systems allow extended analgesia after major breast surgery while maintaining the ambulatory status of the patient. We describe the successful use of continuous paravertebral anesthesia in two patients undergoing major breast surgery. A novel needle system for paravertebral catheter insertion is also presented.

Successful resuscitation after ropivacaine-induced ventricular fibrillation.

Human data about resuscitation after cardiac arrest from ropivacaine are limited. We present a case of successful cardiopulmonary resuscitation after accidental ropivacaine-induced ventricular fibrillation. A 76-yr-old female patient presented for foot osteotomy. A femoral block was performed using a nerve stimulator, a short bevel needle and 20 mL of 1.5% mepivacaine with 1:400,000 epinephrine. The patient remained relaxed and conversant. Five minutes later, an anterior sciatic block was done with 0.5% ropivacaine with 1:400,000 epinephrine for prolonged analgesia. Despite a negative aspiration and incremental injection, the patient developed a tonic-clonic seizure, then gradual widening of the QRS complex, and subsequently ventricular fibrillation. The patient was resuscitated with chest compressions and airway support prior to pharmacologic treatment of defibrillation. Total venous ropivacaine concentration 5 min after the last injection was 3.2 mg/L, free ropivacaine was 0.5 mg/L, and total mepivacaine was 0.22 mg/L. The patient was admitted to the hospital and discharged the next morning without complications. This case demonstrates that techniques used to detect intravascular injection may reduce but not eliminate catastrophic events. Consequently, regional anesthesia using large amounts of local anesthetic should be done in locations with resuscitation equipment and by individuals trained to recognize these complications and begin early treatment.

The difficulties of ambulatory interscalene and intra-articular infusions for rotator cuff surgery: a preliminary report.

PURPOSE: Rotator cuff repair may result in severe postoperative pain. We compared a continuous intra-articular infusion to a continuous interscalene block with ropivacaine for patients undergoing outpatient rotator cuff repair. METHODS: Seventeen patients were randomized to one of two groups: 1) interscalene block with 0.5% ropivacaine (40 mL) followed by a postoperative intra-articular infusion or; 2) interscalene block with 0.5% ropivacaine (40 mL) followed by a postoperative continuous interscalene infusion. Infusions were 0.2% ropivacaine at 10 mL x hr(-1) for both groups. Infusions were maintained for 48 hr. Patients were discharged on the day of surgery. Verbal analogue pain scores (VAS) and postoperative oxycodone consumption were measured for 48 hr. RESULTS: Eight patients (47%; four in each group) had side effects or logistical problems complicating care. The mean VAS scores at rest and with movement in the postanesthesia care unit and at 12 hr, 24 hr, and 48 hr were not different (P > 0.1). Inadequate analgesia was reported in 50-75% of all study patients. Time until first oxycodone use was similar between groups 829 min +/- 432 (interscalene) and 999 min +/- 823 (intra-articular; P = 0.6). Total oxycodone consumption was also similar 49 mg +/- 48 and 59 mg +/- 51 (P = 0.7), respectively. CONCLUSIONS: This study demonstrates the difficulties of ambulatory interscalene and intra-articular infusion for rotator cuff surgery. The high VAS scores and need for additional medical care suggest that intra-articular administration may not be reasonable for this magnitude of surgery. Further refinement of the perineural local anesthetic infusion is necessary to consistently provide analgesia after ambulatory rotator cuff surgery.

Continuous interscalene brachial plexus blockade provides good analgesia at home after major shoulder surgery-report of four cases.

PURPOSE: Continuous interscalene brachial plexus blockade (CIBPB) in a hospital setting can provide excellent surgical conditions and postoperative analgesia for major shoulder surgery. This is a case report of four patients on the efficacy and advantages of CIBPB for postoperative analgesia at home. CASE REPORTS: Four patients scheduled for rotator cuff repair under CIBPB were discharged home the day of surgery with an interscalene catheter connected to an automated infusion pump administering 0.2% ropivacaine at 10 mL x hr(-1) for 72 hr. Prior to discharge, patients and their attendant were given verbal and written instructions concerning local anesthetic toxicity and explicit contact information for an anesthesiologist or nurse. Outcomes were measured pre- and postoperatively, including verbal analogue pain scores (pain VAS), verbal analogue nausea scores (nausea VAS), side effects, cognitive function (mini-mental state questionnaire), sleep (hours/night), and patient satisfaction (Likert scale). Postoperative VAS scores over three days were very low. Two patients reported only one episode of nausea. There were no complications associated with local anesthetic toxicity or catheter use. Cognitive function improved over three days. Sleep increased from a mean of five hours before surgery to seven hours over the next three nights. Patient satisfaction with care was high. Significant cost savings were documented. CONCLUSION: The use of CIBPB for 72 hr in patients undergoing major ambulatory shoulder surgery can result in good analgesia with minimal opioid requirement, cost savings and possibly improvement in outcome measures.

Outcome after regional anaesthesia in the ambulatory setting--is it really worth it?

Regional anaesthesia provides a continuum of perioperative care that includes perioperative pain management, decreased opioid requirements and decreased post-operative nausea and vomiting. In addition to these benefits, a wide variety of perioperative outcomes can be enhanced by utilizing regional anaesthesia in the ambulatory setting. Regional anaesthesia has been shown to improve the cardiovascular, pulmonary, gastrointestinal, coagulative, immunological and cognitive functions and to be of benefit in an economic context. These improvements are particularly advantageous in caring for elderly and high-risk patient populations undergoing surgery. In addition, regional anaesthesia can facilitate early recovery with excellent post-operative analgesia and few side-effects, which may decrease overall operative costs. This chapter identifies important perioperative outcomes that may be positively influenced by the use of regional anaesthesia in the ambulatory setting.