Regional anesthesia techniques for ambulatory orthopedic surgery

Baricity of spinal bupivacaine and the incidence of hypotension in non-obstetric surgery: A systematic review

Bupivacaine is commonly used for spinal anaesthesia. The baricity of bupivacaine (isobaric vs. hyperbaric) may influence the spread, level of the block and the subsequent haemodynamic effects of the spinal anaesthesia. This review considers the available literature on the effect of baricity on the haemodynamic sequelae of spinal anaesthesia with bupivacaine. A literature search was conducted of the MEDLINE and EMBASE databases up to February 2024, following PRISMA guidelines. Randomised controlled trials (RCTs) comparing isobaric and hyperbaric bupivacaine in non-obstetric surgeries were included. Ten studies comprising 586 patients were included. While the literature suggests a trend towards greater incidence of hypotension with hyperbaric bupivacaine, no statistically significant difference was found. Variations in bupivacaine doses and volumes, spinal techniques and definitions of hypotension hindered definitive conclusions. Lower doses relevant to current practice also remain underexplored.

Regional anaesthesia for ambulatory surgery

Regional anaesthesia (RA) has an important and ever-expanding role in ambulatory surgery. Specific practices vary depending on the preferences and resources of the anaesthesia team and hospital setting. It is used for various purposes, including as primary anaesthetic technique for surgery but also as postoperative analgesic modality. The limited duration of action of currently available local anaesthetics limits their application in postoperative pain control and enhanced recovery. The search for the holy grail of regional anaesthetics continues. Current evidence suggests that a peripheral nerve block performed with long-acting local anaesthetics in combination with intravenous or perineural dexamethasone gives the longest and most optimal sensory block. In this review, we outline some possible blocks for ambulatory surgery and additives to perform RA. Moreover, we give an update on local anaesthesia drugs and adjuvants, paediatric RA in ambulatory care and discuss the impact of RA by COVID-19.

Comparison of unilateral spinal anaesthesia with ultrasound-guided combined sciatic and femoral nerve block in elective arthroscopic knee surgeries

Background

Arthroscopic knee surgeries are commonly performed orthopaedic procedures, which can be done under unilateral spinal anaesthesia (USA) or ultrasound-guided combined sciatic and femoral nerve block (USFB). However, not many studies have compared both these techniques. Hence this study was undertaken to compare USA and USFB in arthroscopic knee surgeries in terms of time to readiness for discharge (TRD).

Methods

Eighty patients were randomised into the USA (n = 40) and USFB groups (n = 40). They were administered either USA or USFB on the affected side. The TRD values were compared. Patients were considered fit for discharge after voiding urine, ambulation and obtaining a visual analogue scale (VAS) score of <3. The maximum time required for any of the three parameters was taken as the TRD for that particular patient.

Results

The mean TRD was 595.41 ± 195.69 min in the USA group and 351.86 ± 129.51 min in the USFB group (p < 0.001). The median VAS scores for postoperative pain assessment were lower in the USFB group at 2, 4, 12 and 24 h (p < 0.05). The number of patients requiring rescue analgesia was lower in the USFB group at 6 and 12 h after surgery (p < 0.05).

Conclusion

Patients undergoing arthroscopic knee surgeries under USFB have an advantage when it comes to TRD as these patients have comparatively better postoperative analgesia, less requirement of rescue analgesia, early voiding of urine and early ambulation.

Supplemental Regional Block Anesthesia Reduces Opioid Utilization Following Free Flap Reconstruction of the Oral Cavity: A Prospective, Randomized Clinical Trial

PURPOSE

Regional anesthesia has been shown to effectively manage acute pain and reduce opioid utilization in the early postoperative period following colorectal, orthopedic, and thoracic surgeries. The same effect, however, has not been demonstrated in major head and neck surgery. The purpose of this study is to determine whether supplemental regional anesthesia reduces opioid utilization following microvascular free flap reconstruction of the oral cavity.

METHODS

A prospective, randomized clinical trial was conducted for patients undergoing oral cavity reconstruction using microvascular free tissue transfer between January 2020 and March 2022. The predictor variable was a regional anesthetic nerve block, delivered preoperatively, at the flap donor site. The primary and secondary outcomes were opioid utilization, measured in oral morphine equivalent (OME), from postoperative day 1 to 5, and hospital length of stay (LOS), respectively. Covariates included age, sex, tobacco and alcohol history, prior radiation therapy, pathology, oral site, flap type, tracheostomy, and neck dissection. Student's t test, χ² test, and linear regression models were computed using correlations with 95% confidence intervals (CIs). For all statistical tests, P values of <.05 were regarded as statistically significant.

RESULTS

Ninety-eight participants completed the study. The mean age was 56 years with 55% male. Forty-eight patients received a presurgical regional anesthesia block, and 50 patients served as control subjects. Bivariate analysis demonstrated an even distribution of all study variables. Total OME utilization was significantly less in the treatment group compared to the control group, (166.32 vs 118.43 OME; 95% CI, 1.32 to 94.45; P = .04). The LOS was comparable (6.60 vs 6.48 days; 95% CI, -0.53 to 0.77; P = .71). Tobacco use had a positive effect (B = 0.28; 95% CI, 21.63 to 115.31; P = .005) while the block had a negative effect with total OME, (B = -0.19; 95% CI, -90.39 to -0.59; P = .047). The extent of the neck dissection (B = 0.207; 95% CI, 0.026 to 1.403; P = .042) was a positive predictor for LOS. Overall, there were no adverse events associated with the regional block throughout the study period.

CONCLUSIONS

Supplemental regional anesthesia is safe and associated with reduced opioid utilization in patients undergoing vascularized free flap reconstruction of composite oral cavity defects and does not prolong the length of hospitalization.

Efficacy of single-shot adductor canal block before Versus after primary total knee arthroplasty - Does timing make a difference? A randomized controlled trial

BACKGROUND

Total knee arthroplasty (TKA) is associated with severe postoperative pain. Multimodal analgesia, including peripheral nerve block, is recommended for post-operative pain relief. Administration of some pain medications prior to surgery has shown to be more effective than after the operation. This is a prospective, randomized controlled trial designed to compare the analgesic efficacy of the adductor canal block (ACB) performed immediately before or immediately after primary total knee arthroplasty (TKA). We hypothesized that ACB before the surgery will reduce postoperative pain and improve knee function.

METHODS

A total of 50 patients were enrolled and randomized into 2 groups, with 26 patients receiving a preoperative ACB and 24 receiving a postoperative ACB.

RESULTS

Treatment groups were similar in terms of gender (p = .83), age (p = 0.61) weight (p = .39) and ASA score. Average visual analogue scale (VAS) on arrival to the post-anesthesia care unit (PACU) were 4.9 ± 3.2 in the preoperative ACB versus 3.4 ± 2.8 for the postoperative ACB (p = .075). VAS scores at different time points as well as the mean, minimal and maximal reported VAS scores were not significantly different between the two groups. The cumulative quantities of Fentanyl administered by the anesthesia team was comparable between the groups. Similarly, the dosage of Morphine, Tramadol, Acetaminophen and Dipyrone showed only small variations. The Quality of Recovery Score, Knee Society Scores and knee range of motion did not differ between the groups.

CONCLUSIONS

Our findings demonstrate no significant differences in patient total narcotics consumption, pain scores and functional scores, between preoperative and postoperative ACB in patients undergoing TKA.

TRIAL REGISTRATION

The trial was registered at www.clinicaltrials.gov and was assigned the registration number NCT02908711.

LEVEL OF EVIDENCE

level I randomized controlled trial.

Factors affecting perioperative patient satisfaction with regional anesthesia: A patient-centered survey study

Objective: To determine the demographic and clinical characteristics that affect patient satisfaction with regional anesthesia. Methods: This study was conducted at Kahramanmaras Sutcu Imam University Hospital between June-July 2019. The patients were included on a voluntary basis and all had undergone obstetrics, urology, orthopedics, or general surgery, and met the following inclusion criteria: (1) age >18 years, (2) received regional anesthesia, (3) ASA-PS score of ≤ 3, and (4) no cognitive problem that would prevent self-expression. A Personal Information Form and the Evaluation of the Experience of Regional Anesthesia Questionnaire were applied to 402 patients at 48 hours after surgery performed under regional anesthesia in a university hospital in Turkey. Results: The EVAN-LR total scores were 71.2±15.6 in obstetrics patients, followed by 54.9±24.9 in orthopedic patients, 26.6±24.4 in urology patients and 15.9±7.2 in general surgery patients (p

Evaluation of preemptive interspace between the popliteal artery and the capsule of the posterior knee (IPACK) block for ostoperative pain management in arthroscopic knee surgeries: a retrospective study

Background: Interspace between the popliteal artery and the capsule of the posterior knee (IPACK) block is block, which is done by infiltration of local anesthetic to block terminal branches of genicular nerves and popliteal plexus that innervate the posterior capsule of the knee joint. In this study, we retrospectively reviewed our patient’s data to which IPACK block was applied for arthroscopic knee surgery. Our aim was to evaluate the effectiveness of IPACK block on postoperative analgesia, effects on additional analgesic consumption and patient satisfaction. Material and Method: The data of 60 patients who underwent arthroscopic knee surgery under spinal anesthesia with or without applied preemptive IPACK block for postoperative analgesia were collected between October 2019 and December 2020. Group I consisted of 30 patients with preemptive IPACK block, while 30 patients without block were classified as the control group (Group II). Postoperative 0-1-2-6-12 and 24th hour VAS scores, additional analgesic needs, patient satisfaction scores, were compared in groups as primary outcome. Results: As a result of the comparison between the groups, it was seen that there was a significant difference between the groups in favor of the IPACK Block group in terms of postoperative VAS scores after 1st hour, postoperative analgesic needs and patient satisfaction (p

High turnover for ambulatory orthopedic surgery

PURPOSE OF REVIEW

The trend in the perioperative management of patients having orthopedic surgery in the ambulatory setting emphasizes time-efficiency and rapid turnovers. Anesthetic techniques and management continue to evolve to increase efficiency and decrease time spent in recovery.

RECENT FINDINGS

Minimizing time patients spend in phase 1 recovery or bypassing phase 1 altogether, known as fast-tracking, has become an important goal in containing costs in high turnover, ambulatory settings. Anesthetic techniques, particularly implementation of regional anesthesia and multimodal analgesia, have evolved to maximize efficiency.

SUMMARY

Anesthetic goals in the setting of high-turnover orthopedic surgery include effective multimodal analgesia, decreasing monotherapy with opioids, and patient education. Regional anesthesia as part of a multimodal analgesic regimen is increasingly used in ambulatory surgery fast-tracking protocols.

Techniques and strategies for regional anesthesia in acute burn care-a narrative review

Burn injuries and their treatments result in severe pain. Unlike traumatic injuries that are characterized by a discrete episode of pain followed by recovery, burn-injured patients endure pain for a prolonged period that lasts through wound closure (e.g. background pain, procedural pain, breakthrough pain, neuropathic pain and itch). Regional anesthesia, including peripheral nerve blocks and neuraxial/epidural anesthesia, offers significant benefits to a multimodal approach in pain treatment. A 'regional-first' approach to pain management can be incorporated into the workflow of burn centers through engaging regional anesthesiologists and pain medicine practitioners in the care of burn patients. A detailed understanding of peripheral nerve anatomy frames the burn clinician's perspective when considering a peripheral nerve block/catheter. The infra/supraclavicular nerve block provides excellent coverage for the upper extremity, while the trunk can be covered with a variety of blocks including erector spinae plane and quadratus lumborum plane blocks. The lower extremity is targeted with fascia iliaca plane and sciatic nerve blocks for both donor and recipient sites. Burn centers that adopt regional anesthesia should be aware of potential complications and contraindications to prevent adverse events, including management of local anesthetic toxicity and epidural infections. Management of anticoagulation around regional anesthesia placement is crucial to prevent hematoma and nerve damage. Ultimately, regional anesthesia can facilitate a better patient experience and allow for early therapy and mobility goals that are hallmarks of burn care and rehabilitation.

The effects of isobaric and hyperbaric bupivacaine on maternal hemodynamic changes post spinal anesthesia for elective cesarean delivery: A prospective cohort study

BACKGROUND

Spinal anesthesia is a form of regional anesthesia frequently used in various lower abdominal, orthopedic, obstetric operations such as a cesarean delivery. The most common local anesthetic used for spinal anesthesia in obstetric and non-obstetric surgery is bupivacaine which can be utilized as an isobaric or hyperbaric solution, producing differences in maternal hemodynamic changes. Against this backdrop, the study aims to compare the effects of isobaric and hyperbaric bupivacaine on maternal hemodynamic alterations after administering spinal anesthesia for elective cesarean delivery at Gandhi Memorial Hospital, Addis Ababa, Ethiopia.

METHODS

A hospital-based prospective cohort study design was employed for the period December 1, 2017 to January 30, 2018. A total of 100 parturient were involved, with one group exposed to isobaric bupivacaine and the other to hyperbaric bupivacaine to observe their effects on maternal hemodynamic changes post spinal anesthesia. The participants were selected through systematic random sampling. Data analysis was performed using SPSS (version 20) through descriptive statistic, independent sample t-test, Mann-Whitney U-test, Fisher's exact test, and Chi-square test were used. P values of <0.05 was assumed as statistically significant for all tests.

RESULTS

The incidence of hypotension was found to be greater in isobaric than hyperbaric groups (82% vs. 60% respectively; p = 0.015). No statistical significant differences were found in mean arterial pressure value at baseline, but, statistically significant changes were observed among the groups (p <0.05) at all study timing after spinal anesthesia, except at 30thmin. No statistically significant differences were seen in the mean heart rate variability after spinal anesthesia at all periods, except the 15th minute (p = 0.033). A greater rate of vasopressor was used in the isobaric group as compared to the hyperbaric group (36% vs. 14% respectively; p = 0.011).

CONCLUSION

Baricity is a significant factor in maternal hemodynamic changes in the parturient for elective cesarean section. Isobaric bupivacaine produces greater change in blood pressure and incidence of hypotension and entails a greater vasopressor requirement than hyperbaric bupivacaine after spinal anesthesia for elective cesarean section.

Serotonin enhances oxybuprocaine- and proxymetacaine-induced cutaneous analgesia in rats

The aim of the study was to investigate the analgesic effects of adding serotonin to oxybuprocaine or proxymetacaine preparations. We employed a rat model of the cutaneous trunci muscle reflex (CTMR) to conduct the dose-response curves and duration of drugs (oxybuprocaine, proxymetacaine, or serotonin) as an infiltrative anesthetic. The use of isobolographic methods to analyze the drug-drug interactions. We showed that oxybuprocaine and proxymetacaine, as well as serotonin produced dose-dependent skin antinociception. On the basis of 50% effective dose (ED50), the rank order of drug potency was serotonin [7.22 (6.45-8.09) μmol/kg] < oxybuprocaine [1.03 (0.93-1.15) μmol/kg] < proxymetacaine [0.59 (0.53-0.66) μmol/kg] (P < 0.01 for each comparison). The sensory block duration of serotonin was longer (P < 0.01) than that of oxybuprocaine or proxymetacaine at the equipotent doses (ED25, ED50, and ED75). The mixture of serotonin with oxybuprocaine or proxymetacaine produced a better analgesic effect than the drug itself. We have concluded that oxybuprocaine, proxymetacaine, or serotonin displays dose-related cutaneous analgesia. Oxybuprocaine or proxymetacaine is more potent and has a shorter duration of cutaneous analgesia than serotonin. Serotonin produces a synergistic antinociceptive interaction with oxybuprocaine or proxymetacaine.

Perioperative Care of Elderly Surgical Outpatients

The ambulatory setting offers potential advantages for elderly patients undergoing elective surgery due to the advancement in both surgical and anesthetic techniques resulting in quicker recovery times, fewer complications, higher patient satisfaction, and reduced costs of care. This review article aims to provide a practical guide to anesthetic management of elderly outpatients. Important considerations in the preoperative evaluation of elderly outpatients with co-existing diseases, as well as the advantages and disadvantages of different anesthetic techniques on a procedural-specific basis, and recommendations regarding the management of common postoperative complications (e.g., pain, postoperative nausea and vomiting [PONV], delirium and cognitive dysfunction, and gastrointestinal dysfunction) are discussed. The role of anesthesiologists as perioperative physicians is important for optimizing surgical outcomes for elderly patients undergoing ambulatory surgery. The implementation of high-quality, evidence-based perioperative care programs for the elderly on an ambulatory basis has assumed increased importance. Optimal management of perioperative pain using opioid-sparing multimodal analgesic techniques and preventing PONV using prophylactic antiemetics are key elements for achieving enhanced recovery after surgery.

Atlanto-occipital catheterization of young rats for long-term drug delivery into the lumbar subarachnoid space combined with in vivo testing and electrophysiology in situ

BACKGROUND

Catheterization has been widely used in neuroscience and pain research for local drug delivery. Though different modifications were developed, the use of young animals for spinal catheterization remains limited because of a little success rate. A reliable technique is needed to catheterize young animals aimed for in vivo testing combined with spinal cord electrophysiology, often limited by animal age, to facilitate pain research.

NEW METHODS

We describe intrathecal catheterization of young rats (3-week-old) through atlanto-occipical approach for long-lasting drug delivery into the lumbar subarachnoid space. The technique represents a surgical approach of minimized invasiveness that requires PE-10 catheter and few equipment of standard laboratory use.

RESULTS

Behavioral assessments revealed that spinal catheterization does not change peripheral sensitivity of different modalities (thermal and mechanical) and gives no rise to locomotive deficit or anxiety-like behavior in young rats. The long-term administration of genetic material (oligodeoxynucleotides given up to 4days), examined both in vivo and in situ, produced no adverse effects on basal peripheral sensitivity, but changed the AMPA receptor-mediated currents in sensory interneurons of the spinal cord.

COMPARISON WITH EXISTING METHODS

Dissimilar to already described methods, the method is designed for the use of young rats for behavioral testing in vivo and/or spinal cord electrophysiology in situ.

CONCLUSIONS

A practical method for spinal catheterization of young animals designed for studies in vivo and in situ is proposed. The method is rapid and effective and should facilitate investigation of therapeutic effects on both systemic and subcellular levels, as an advantage over the existing methods.

Comparison of 2-Chloroprocaine, Bupivacaine, and Lidocaine for Spinal Anesthesia in Patients Undergoing Knee Arthroscopy in an Outpatient Setting: A Double-Blind Randomized Controlled Trial

BACKGROUND AND OBJECTIVES

Knee arthroscopy is a well-established procedure in day-case surgery, which is frequently performed under spinal anesthesia. It is, however, controversial whether the choice for a specific local anesthetic translates into relevant outcomes. We hypothesized that the use of 2-chloroprocaine would be associated with a faster recovery from sensorimotor block.

METHODS

Ninety-nine patients were included in this prospective, double-blind, randomized controlled trial and randomly allocated to receive either 40 mg 2-chloroprocaine, 40 mg lidocaine, or 7.5 mg bupivacaine. The primary endpoint was the time until complete recovery of sensory block. Secondary endpoints included time to recovery from motor block, failure rates, incidence of hypotension/bradycardia, postoperative pain, first mobilization, voiding and discharge times, and the incidence of transient neurologic symptoms. This clinical trial was registered prior to patient enrollment (EudraCT 2011-003675-11).

RESULTS

Patients in the chloroprocaine group had a significantly shorter time until recovery from sensory block (median, 2.6 hours; interquartile range [IQR], 2.2-2.9 hours) than patients in the lidocaine group (3.1 hours; IQR, 2.7-3.6 hours; P < 0.006) and in the bupivacaine group (6.1 hours; IQR, 5.5 hours to undefined hours; P < 0.0001). Chloroprocaine was associated with a significantly faster recovery from motor block than lidocaine and bupivacaine. Times to first mobilization, voiding, and discharge were significantly shorter for chloroprocaine when compared with bupivacaine, but not with lidocaine. In the bupivacaine group, patients needed significantly less rescue medication for postoperative pain when compared with lidocaine and chloroprocaine. Groups did not differ with respect to patient satisfaction, incidence of bradycardia/hypotension, and transient neurologic symptom rate.

CONCLUSIONS

For spinal anesthesia in patients undergoing ambulatory knee arthroscopy, chloroprocaine has the shortest time to complete recovery of sensory and motor block compared with bupivacaine and lidocaine.

Preoperative evaluation and preparation of patients for orthopedic surgery

Orthopedic patients frequently have multiple comorbidities when they present for surgery. This article discusses risk stratification of this population and the preoperative work-up for patients with specific underlying conditions who often require orthopedic procedures. Preoperative strategies to decrease exposure to allogeneic blood and advantages of the Perioperative Surgical Home model in this unique population are discussed.

Pain management in ambulatory surgery-a review

Day surgery, coming to and leaving the hospital on the same day as surgery as well as ambulatory surgery, leaving hospital within twenty-three hours is increasingly being adopted. There are several potential benefits associated with the avoidance of in-hospital care. Early discharge demands a rapid recovery and low incidence and intensity of surgery and anaesthesia related side-effects; such as pain, nausea and fatigue. Patients must be fit enough and symptom intensity so low that self-care is feasible in order to secure quality of care. Preventive multi-modal analgesia has become the gold standard. Administering paracetamol, NSIADs prior to start of surgery and decreasing the noxious influx by the use of local anaesthetics by peripheral block or infiltration in surgical field prior to incision and at wound closure in combination with intra-operative fast acting opioid analgesics, e.g., remifentanil, have become standard of care. Single preoperative 0.1 mg/kg dose dexamethasone has a combined action, anti-emetic and provides enhanced analgesia. Additional α-2-agonists and/or gabapentin or pregabalin may be used in addition to facilitate the pain management if patients are at risk for more pronounced pain. Paracetamol, NSAIDs and rescue oral opioid is the basic concept for self-care during the first 3–5 days after common day/ambulatory surgical procedures.

Comparison between ultrasound-guided sciatic–femoral nerve block and unilateral spinal anaesthesia for outpatient knee arthroscopy

Objective

To compare unilateral spinal anaesthesia (USA) and ultrasound-guided combined sciatic–femoral nerve block (USFB) in ambulatory arthroscopic knee surgeries in terms of haemodynamic stability, nerve block quality, bladder function, adverse events and time-to-readiness for discharge (TRD).

Methods

Patients undergoing ambulatory arthroscopic knee surgery were randomly assigned to one of two groups. The USA group received 2 ml (10 mg) of 0.5% levobupivacaine and the USFB group received a 25 ml mixture consisting of 10 ml of 2.0% lidocaine, 10 ml of 0.5% levobupivacaine and 5 ml of saline (15 ml for the femoral and 10 ml for the sciatic nerve block). Preparation time (PT), surgical anaesthesia time (SAT), operation time, total anaesthesia time, time-to-first spontaneous urination, time-to-first analgesia, TRD, adverse events and patient satisfaction were recorded.

Results

A total of 40 patients were enrolled in the study ( n = 20 per group). PT, SAT, total anaesthesia time and time-to-first analgesia were significantly shorter in the USA group than the USFB group; time-to-first spontaneous urination and TRD were significantly longer in the USA group than the USFB group.

Conclusions

USFB provided sufficient duration of sensory blockade and it reduced the TRD and the rate of adverse events.

Primary payer status is associated with the use of nerve block placement for ambulatory orthopedic surgery

INTRODUCTION

Although more than 30 million patients in the United States undergo ambulatory surgery each year, it remains unclear what percentage of these patients receive a perioperative nerve block. We reviewed data from the 2006 National Survey of Ambulatory Surgery to determine the demographic, socioeconomic, geographic, and clinical factors associated with the likelihood of nerve block placement for ambulatory orthopedic surgery. The primary outcome of interest was the association between primary method of payment and likelihood of nerve block placement. In addition, we examined the association between type of surgical procedures, patient demographics, and hospital characteristics with the likelihood of receiving a nerve block.

METHODS

This cross-sectional study reviewed 6000 orthopedic anesthetics from the 2006 National Survey of Ambulatory Surgery data set, which accounted for more than 3.9 million orthopedic anesthetics when weighted. The primary outcome of this study addressed the likelihood of receiving a nerve block for orthopedic ambulatory surgery according to the patient's primary method of payment. Secondary end points included differences in demographics, surgical procedures, adverse effects, complications, recovery profile, anesthesia staffing model, and total perioperative charges in those with and without nerve block.

RESULTS

Overall, 14.9% of anesthetics in this sample involved a peripheral nerve block. Length of time in postoperative recovery, total perioperative time, and total charges were less for those receiving nerve blocks. Patients were more likely to receive a nerve block if their procedures were performed in metropolitan service areas (odds ratio [OR], 1.86; 95% confidence interval [CI], 1.19-2.91; P = 0.007) or in freestanding surgical facilities (OR, 2.27; 95% CI, 1.74-2.96; P < 0.0001) and if payment for their surgery was supported by government programs (OR, 2.5; 95% CI, 1.01-6.21; P = 0.048) or private insurance (OR, 2.62; 95% CI, 1.12-6.13; P = 0.03) versus self-pay or charity care.

CONCLUSIONS

For patients receiving ambulatory orthopedic surgery in the United States, our results suggest that geographic and socioeconomic factors are associated with different likelihoods of perioperative peripheral nerve block placement.

Perioperative care for the older outpatient undergoing ambulatory surgery

As the number of ambulatory surgery procedures continues to grow in an aging global society, the implementation of evidence-based perioperative care programs for the elderly will assume increased importance. Given the recent advances in anesthesia, surgery, and monitoring technology, the ambulatory setting offers potential advantages for elderly patients undergoing elective surgery. In this review article we summarize the physiologic and pharmacologic effects of aging and their influence on anesthetic drugs, the important considerations in the preoperative evaluation of elderly outpatients with coexisting diseases, the advantages and disadvantages of different anesthetic techniques on a procedural-specific basis, and offer recommendations regarding the management of common postoperative side effects (including delirium and cognitive dysfunction, fatigue, dizziness, pain, and gastrointestinal dysfunction) after ambulatory surgery. We conclude with a discussion of future challenges related to the growth of ambulatory surgery practice in this segment of our surgical population. When information specifically for the elderly population was not available in the peer-reviewed literature, we drew from relevant information in other ambulatory surgery populations.

Evidence-based practice in arthroscopic knee surgery

Knee arthroscopy is a minimally-invasive technique that allows intra-articular assessment and treatment of knee joint pathology. It has proven benefits of reduced patient morbidity, earlier recovery and mobilisation, and it is cost-effective. In this paper we review the anatomy of the knee joint, indications and contra-indications to knee arthroscopic use, and consider the main techniques of knee arthroscopy including types of anaesthetic, prophylactic antibiotics, theatre setup and arthroscopic portals, and post-operative care.

Continuous peripheral nerve blocks in acute pain management

The indications for continuous nerve blocks for the perioperative pain management in hospitalized and ambulatory patients have extended well beyond orthopaedics. These techniques are not only used to control pain in patients undergoing major upper and lower extremity surgery, but also to provide perioperative analgesia in patients undergoing abdominal, plastic, urological, gynaecological, thoracic, and trauma surgeries. Infusion regimens of local anaesthetics and supplements must take into consideration the condition of the patient before and after surgery, the nature and intensity of the surgical stress associated with the surgery, and the possible need for immediate functional recovery. Continuous nerve blocks have proved safe and effective in reducing opioid consumption and related side-effects, accelerating recovery, and in many patients reducing the length of hospital stay. Continuous nerve blocks provide a safer alternative to epidural analgesia in patients receiving thromboprophylaxis, especially with low molecular-weight heparin.

The acute toxicity of local anesthetics

IMPORTANCE OF THE FIELD

Systemic toxicity, usually from overdose or intravascular dose, is feared because it mainly affects the heart and brain, and may be acutely life-threatening.

AREAS COVERED IN THIS REVIEW

Pharmacological studies of local anesthetic toxicity have largely been reviewed primarily relating to the evaluation of ropivacaine and levobupivacaine during the past decade. This review/opinion focuses more on the principles and concepts underlying the main models used, from chemical pharmacological and pharmacokinetic perspectives.

WHAT THE READER WILL GAIN

Research models required to produce pivotal toxicity data are discussed. The potencies for neural blockade and systemic toxicity are associated across virtually all models, with some deviations through molecular stereochemistry. These models show that all local anesthetics can produce direct cardiovascular system toxicity and CNS excitotoxicity that may further affect the cardiovascular system response. Whereas the longer-acting local anesthetics are more likely to cause cardiac death by malignant arrhythmias, the shorter-acting agents are more likely to cause cardiac contraction failure. In most models, equi-anesthetic doses of ropivacaine and levobupivacaine are less likely to produce serious toxicity than bupivacaine.

TAKE HOME MESSAGE

Of the various models, this reviewer favors a whole-body large animal preparation because of the comprehensive data collection possible. The conscious sheep preparation has contributed more than any other, and may be regarded as the de facto 'standard' experimental model for concurrent study of local anesthetic toxicity ± pharmacokinetics, using experimental designs that can reproduce the toxicity seen in clinical accidents.