Stuart A. Grant

Practice Guidelines for Central Venous Access A Report by the American Society of Anesthesiologists Task Force on Central Venous Access

P RACTICE Guidelines are systematically developed recommendations that assist the practitioner and patient in making decisions about health care. These recommendations may be adopted, modified, or rejected according to clinical needs and constraints, and are not intended to replace local institutional policies. In addition, Practice Guidelines developed by the American Society of Anesthesiologists (ASA) are not intended as standards or absolute requirements, and their use cannot guarantee any specific outcome. Practice Guidelines are subject to revision as warranted by the evolution of medical knowledge, technology, and practice. They provide basic recommendations that are supported by a synthesis and analysis of the current literature, expert and practitioner opinion, open forum commentary, and clinical feasibility data.

Interscalene brachial plexus block with a continuous catheter insertion system and a disposable infusion pump.

Continuous interscalene brachial plexus blockade traditionally requires a hospital stay for local anesthetic infusion, and achieving consistent catheter insertion may be difficult. Incorporating long-acting pain relief from a continuous peripheral nerve block, with a reliable method of catheter insertion, and a self-contained infusion system would be a valuable asset for short-stay care. We compared the efficacy of single injection interscalene brachial plexus blockade to a continuous peripheral nerve block, with an insulated Tuohy system and a disposable infusion pump. Forty adult patients scheduled for open rotator cuff repair were entered in this randomized, double-blinded, placebo-controlled study. Patients received an interscalene brachial plexus blockade and a continuous peripheral nerve catheter as their primary anesthetic and then, were assigned to receive one of two different postoperative infusions: either 0.2% ropivacaine at 10 mL/h via a disposable infusion pump or normal saline at 10 mL/h via a disposable infusion pump (n = 18–20 per group). Visual analog pain scores and postoperative morphine consumption were measured for 24 h. The ropivacaine group showed less pain than the placebo group (P = 0.0001) between 12 and 24 h after the initial injection of local anesthetic. In addition, initial interscalene blockade was successful in all patients and all redosed catheters were functional after 24 h with the continuous catheter insertion system. We conclude that it is possible to achieve a high rate of successful catheter placement and analgesia by using the continuous catheter insertion system and a disposable infusion pump in the ambulatory setting. This method of analgesia may offer improved pain relief after outpatient rotator cuff repair. Implications This study demonstrates that it is possible to achieve successful interscalene brachial plexus continuous catheter insertion and a high degree of persistent analgesia by using a catheter insertion system and a disposable infusion pump administering 0.2% ropivacaine.

Continuous peripheral nerve block for ambulatory surgery.

Background and Objectives Adenosine is an endogenous compound that may have analgesic effects. Results from clinical trials are not consistent, however, and there is a need for large-scale, randomized, placebocontrolled studies to clarify the role of adenosine in the treatment of pain states, including acute nociceptive pain and pain involving central sensitization. Methods The analgesic and antihyperalgesic effect of systemic adenosine on the heat/capsaicin sensitization model of experimental pain was investigated in 25 healthy human volunteers. Sensitization was produced by heating the skin to 45°C for 5 minutes, followed by a 30-minute application of 0.075% capsaicin cream, and maintained by periodically reheating the sensitized skin to 40°C for 5 minutes at 40-minute intervals. Subjects received intravenous adenosine 60 μg/kg/min or saline for 85 minutes. Areas of secondary hyperalgesia to von Frey hair and brush stimulation, heat-pain detection thresholds (HPDTs) in normal and sensitized skin, and painfulness of stimulation with 45°C for 1 minute (LTS) in normal skin were quantified before, during, and after study drug infusion. Results Systemic adenosine had no effect on the area of secondary hyperalgesia to von Frey hair or brush stimulation, HPDT in normal or sensitized skin, or painfulness of LTS in normal skin. Conclusion We conclude that adenosine has no effect on acute nociceptive pain induced by heat stimulation or on secondary hyperalgesia induced by heat/capsaicin sensitization in healthy volunteers.

The ASRA evidence-based medicine assessment of ultrasound-guided regional anesthesia and pain medicine: Executive summary.

Objectives: The American Society of Regional Anesthesia and Pain Medicine charged an expert panel to examine the evidence basis for ultrasound guidance as a nerve localization tool in the clinical practices of regional anesthesia and interventional pain medicine. Methods: The panel searched, examined, and assessed the literature of ultrasound-guided regional anesthesia (UGRA) from the past 20 years. The qualities of studies were graded using the Jadad score. Strength of evidence and recommendations were graded using an accepted rating tool. Results: The panel made specific literature-based assessments concerning the relative advantages and limitations of UGRA relative to traditional nerve localization methods as they pertained to block characteristics and complications. Assessments and recommendations were made for upper and lower extremity, neuraxial, and truncal blocks and include pediatrics and interventional pain medicine. Conclusions: Ultrasound guidance improves block characteristics (particularly performance time and surrogate measures of success) that are often block specific and that may impart an efficiency advantage depending on individual practitioner circumstances. Evidence for UGRA impacting patient safety is currently limited to the demonstration of improvements in the frequency of surrogate events for serious complications.

Impact of perioperative allogeneic and autologous blood transfusion on acute wound infection following total knee and total hip arthroplasty.

BACKGROUND Patients undergoing total hip or knee arthroplasty frequently receive blood transfusions. The relationship between transfusion and the risk of infection following total joint arthroplasty is unclear. In this study, we sought to examine the impact of allogeneic and autologous transfusion on the risk of acute infection following total hip and total knee arthroplasty. METHODS We performed a retrospective study of consecutive primary total knee arthroplasties and total hip arthroplasties. Patients who had a reoperation for suspected infection within three months after the arthroplasty were identified. Differences in risk factors were assessed across transfusion groups: no transfusion, autologous only, and allogeneic exposure (allogeneic with or without additional autologous transfusion). Backward-stepwise logistic regression analysis was used to compare reoperations (as outcomes) between cases with and those without allogeneic exposure. Prespecified covariates were body mass index, diabetes, an American Society of Anesthesiologists (ASA) score of >2, preoperative hematocrit, and total number of units transfused perioperatively. RESULTS We identified 3352 patients treated with a total hip or knee arthroplasty (1730 total knee arthroplasties and 1622 total hip arthroplasties) for inclusion in the study. Transfusion was given in 1746 cases: 836 of them had allogeneic exposure, and 910 had autologous-only transfusion. There were thirty-two reoperations (0.95%) for suspected infection. Between-group risk-factor differences were observed. The mean age and the rates of diabetes, immunosuppression, ASA scores of >2, and bilateral surgery were highest in the allogeneic group, as were estimated blood loss, surgery duration, and total number of units transfused (p < 0.001). In the unadjusted analyses, the rate of reoperations for suspected infection was higher in the cases with allogeneic exposure (1.67%) than in those without allogeneic exposure (0.72%) (p = 0.013). Autologous-only transfusion was not associated with a higher reoperation rate. However, multivariable logistic regression demonstrated that the total number of units transfused (p = 0.011) and an ASA score of >2 (p = 0.008)-but not allogeneic exposure-were significantly predictive of a reoperation. CONCLUSIONS Perioperative allogeneic transfusion was associated with a higher rate of reoperations for suspected acute infection. However, patients with allogeneic exposure had increased infection risk factors. After adjustment for the total number of units transfused and an ASA score of >2, allogeneic exposure was not significantly predictive of a reoperation for infection.

Central nervous system toxicity following the administration of levobupivacaine for lumbar plexus block: A report of two cases.

Background and Objectives Central nervous system and cardiac toxicity following the administration of local anesthetics is a recognized complication of regional anesthesia. Levobupivacaine, the pure S(-) enantiomer of bupivacaine, was developed to improve the cardiac safety profile of bupivacaine. We describe 2 cases of grand mal seizures following accidental intravascular injection of levobupivacaine. Case Report Two patients presenting for elective orthopedic surgery of the lower limb underwent blockade of the lumbar plexus via the posterior approach. Immediately after the administration of levobupivacaine 0.5% with epinephrine 2.5 μg/mL, the patients developed grand mal seizures, despite negative aspiration for blood and no clinical signs of intravenous epinephrine administration. The seizures were successfully treated with sodium thiopental in addition to succinylcholine in 1 patient. Neither patient developed signs of cardiovascular toxicity. Both patients were treated preoperatively with β-adrenergic antagonist medications, which may have masked the cardiovascular signs of the unintentional intravascular administration of levobupivacaine with epinephrine. Conclusions Although levobupivacaine may have a safer cardiac toxicity profile than racemic bupivacaine, if adequate amounts of levobupivacaine reach the circulation, it will result in convulsions. Plasma concentrations sufficient to result in central nervous system toxicity did not produce manifestations of cardiac toxicity in these 2 patients.

Continuous versus single-injection lumbar plexus blocks: comparison of the effects on morphine use and early recovery after total knee arthroplasty.

Background and Objectives: Continuous lumbar plexus infusion of local anesthetic after total knee arthroplasty has been shown to improve analgesia and early recovery as compared with patient-controlled analgesia (PCA) morphine. Any benefit of an infusion over a single-injection lumbar plexus block has not been directly shown however. Methods: In a double-blind, randomized, controlled trial, 32 patients undergoing total knee arthroplasty were randomly allocated to 1 of 2 groups: 0.1% levobupivacaine infusion or saline infusion. Preoperatively, all patients received a lumbar plexus block with 25 mL 0.5% levobupivacaine using a posterior approach with a catheter left in situ, a sciatic nerve block with 15 mL 0.5% levobupivacaine, and a spinal anesthetic. At the end of surgery, 0.1% levobupivacaine or saline was infused into the catheter at 10 mL/h for 48 hours. All patients also received PCA morphine. The primary endpoint was morphine use from the PCA machine. Secondary endpoints included pain scores, day of first postoperative mobilization, and nausea. Results: Patients receiving the levobupivacaine infusion used significantly less morphine than those receiving saline (19 mg [interquartile range (IQR) 8.5-29.5] vs 32 mg [IQR 23.5-53.0], P = .04) and also mobilized earlier postoperatively (day 1 or 2 [levobupivacaine] vs day 2 or 3 [saline], P = .001). Pain scores were similar. Conclusion: Postoperative infusion of local anesthetic around the lumbar plexus reduces morphine requirement and improves early recovery after total knee arthroplasty as compared with a single-injection block.

Ambulatory surgery for multi-ligament knee reconstruction with continuous dual catheter peripheral nerve blockade.

Purpose: Major reconstructive surgery of the knee traditionally requires an extended hospital stay for pain management. Continuous peripheral nerve blockade is an alternative method of pain control but is seldom used in the ambulatory setting. This case illustrates the use of lumbar plexus and sciatic nerve peripheral catheters for major knee surgery using intermittent bolus dosing for outpatient analgesia.Clinical features: A 20-yr-old male presented for multi-ligamentous knee reconstruction (posterior collateral ligament and revision anterior collateral ligament and lateral collateral ligament). Anesthesia was managed with a lumbar plexus and a sciatic nerve peripheral catheter and a light general anesthetic. Post-operative analgesia was provided with a 12-hr infusion of 0.2% ropivacaine in an over night recovery care centre. Subsequent catheter dosing was performed as an outpatient, twice a day using 0.2% ropivacaine, 10 ml in each catheter (four injections total). This provided 96 hr of analgesia and low supplemental opioid use.Conclusion: The use of a lumbar plexus and sciatic nerve peripheral catheter offered an alternative to conventional pain control that worked well in the ambulatory setting. By providing prolonged unilateral lower limb analgesia, extensive knee surgery was performed that would normally require a hospital stay for pain control. Using a bolus dosing method the risk of local anesthetic complications occurrning outside of the hospital with a continuous infusion was minimized.RésuméObjectif: Le soulagement de la douleur postopératoire d’une reconstruction majeure du genou nécessite habituellement un séjour prolongé à l’hôpital. Le blocage nerveux périphérique permet aussi de contrôler la douleur, mais est rar ement utilisée chirurgie ambulatoire. On présente un cas d’opération majeure du genou où l’analgésie ambulatoire a requis l’administration de bolus intermittents par cathéters périphériques ua plexus lombaire et au nerf sciatique.Éléments cliniques: Un homme de 20 ans devait subir une reconstruction multi-ligamentaire du genou (ligament colatéral postérjeur et revue des ligaments collatéraux antérieur et latéral). Une anesthésie générale légère a été administrée, associée avec l’utilisation d’un cathéter périphérique au plexus lombaire et au nerf sciatique. L’analgésie postopératoire a consisté en une perfusion de ropivacaïne à 0,2 %, administrée pendant 12 h, la première nuit, dans un centre de convalescence. Le dosage subséquent de l’analgésie par cathéter a été réalisé dans un contexte ambulatoire, deux fois par jour, avec de la ropivacaïne à 0,2 %, 10 ml dans chaque cathéter (quatre injections en tout). Cette technique a fourni 96 h d’analgésie et n’a demandé qu’un faible supplément d’opioïde.Conclusion: Le blocage périphérique du plexus lombaire et du nerf sciatique, en remplacement de la technique traditionnelle d’analgésie postopératoire, a été efficace dans un contexte ambulatoire. L’analgésie unilatérale prolongé du membre inférieur a permis une opération étendue du genou et évité l’habituel séjour hospitalier nécessaire au soulagement de la douleur postopératoire. Le dosage par bolus a réduit le risque de complications, reliés à l’anestheésique local, qui surviennent à l7rsextérieur de l’hôpital lorsqu’on utilise des perfusions continues.

Development of a standardized peripheral nerve block procedure note form

Objectives: Despite the tremendous growth of peripheral nerve blocks, no standard format exists to document their performance. Our objective was to create a peripheral nerve block form based on key elements of literature evidence and on our own group consensus. Results: We describe the process and results of our multi-institutional effort to construct a standardized peripheral nerve block procedure form. Conclusion: A form was developed to help meet the medical, legal, and billing requirements of documentation consistent with the performance of peripheral nerve block.

On the feasibility of imaging peripheral nerves using acoustic radiation force impulse imaging.

Regional anesthesia is preferred over general anesthesia for many surgical procedures; however, challenges associated with poor image guidance limit its widespread acceptance as a viable alternative. In B-mode ultrasound images, the current standard for guidance, nerves can be difficult to visualize due to their similar acoustic impedance with surrounding tissues and needles must be aligned within the imaging plane at limited angles of approach that can impede successful peripheral nerve anesthesia. These challenges lead to inadequate regional anesthesia, necessitating intraoperative interventions, and can cause complications, including hemorrhage, intraneural injections and even nerve paralysis. ARFI imaging utilizes acoustic radiation force to generate images that portray relative tissue stiffness differences. Peripheral nerves are typically surrounded by many different tissue types (e.g., muscle, fat and fascia) that provide a mechanical basis for improved image contrast using ARFI imaging over conventional B-mode images. ARFI images of peripheral nerves and needles have been generated in cadaveric specimens and in humans in vivo. Contrast improvements of >600% have been achieved for distal sciatic nerve structures. The brachial plexus has been visualized with improved contrast over B-mode images in vivo during saline injection and ARFI images can delineate nerve bundle substructures to aid injection guidance. Physiologic motion during ARFI imaging of nerves near arterial structures has been successfully suppressed using ECG-triggered image acquisition and motion filters. This work demonstrates the feasibility of using ARFI imaging to improve the visualization of peripheral nerves during regional anesthesia procedures.