Gabriella Iohom

The associations between severity of early postoperative pain, chronic postsurgical pain and plasma concentration of stable nitric oxide products after breast surgery.

In this study, we compared the effects of two analgesic regimens on perioperative nitric oxide index (NOx) and the likelihood of subsequent development of chronic postsurgical pain (CPSP) after breast surgery and sought to determine the association among early postoperative pain, NOx, and the likelihood of subsequent development of CPSP. Twenty-nine consecutive ASA I or II patients undergoing breast surgery with axillary clearance were randomly allocated to one of two groups. Patients in group S (n = 15) received a standard intraoperative and postoperative analgesic regimen (morphine sulfate, diclofenac, dextropropoxyphene hydrochloride + acetaminophen prn). Patients in group N (n = 14) received a continuous paravertebral block (for 48 h) and acetaminophen and parecoxib (followed by celecoxib up to 5 days). Visual analog scale pain scores at rest and on arm movement were recorded regularly until the fifth postoperative day. A telephone interview was conducted 10 wk postoperatively. The McGill Pain Questionnaire was used to characterize pain. NOx was estimated preoperatively, at the end of surgery, 30 min and 2, 4, 12, 24, 48 h postoperatively. Twelve (80%) patients in group S and no patient in group N developed CPSP (P = 0.009). Compared with patients with a pain rating index ≥1 (n = 18) 10 wk postoperatively, patients with a pain rating index = 0 (n = 11) had lesser visual analog scale pain scores on movement at each postoperative time point from 30 min until 96 h postoperatively (P < 0.005) and at rest 30 min (0.6 ± 1.5 versus 30.2 ± 26.8; P = 0.004), 4 h (2.3 ± 7.5 versus 19.0 ± 25.8; P = 0.013), 8 h (4.4 ± 10.2 versus 21.4 ± 27.0; P = 0.03) and 12 h (0.7 ± 1.2 versus 15.4 ± 27.0; P = 0.035) postoperatively. NOx values were greater in group N compared with group S 48 h postoperatively (40.6 ± 20.1 versus 26.4 ± 13.5; P = 0.04).

The effects of clonidine added to mepivacaine for paronychia surgery under axillary brachial plexus block

We hypothesized that onset of sensory block is delayed in infected versus healthy tissues within the same nerve distribution after axillary brachial plexus block (ABPB) and that clonidine added to mepivacaine would enhance anesthesia and postoperative analgesia. Forty-one outpatients undergoing thumb/index paronychia surgery under ABPB were randomly assigned to receive in a double-blind fashion 400 mg mepivacaine plus either 100 &mgr;g clonidine (clonidine group, n = 21) or 2 mL saline (placebo group, n = 20). Onset of sensory block in the infected area was delayed compared with healthy areas of the same nerve distribution (24.7 ± 5.5 min versus 21.3 ± 7.2; P = 0.02 for median and 21.6 ± 7.8 min; P = 0.04 for radial) within the placebo group. In the clonidine group, when compared to placebo i) onset of sensory block in both the median and radial nerve territories was accelerated (11.1 ± 5.6 and 10.5 ± 5.2 versus 21.3 ± 7.2 and 21.6 ± 7.8 min, respectively; P < 0.001), ii) onset of sensory block in the region of infection was accelerated (9.1 ± 1.9 versus 24.7 ± 5.5 min; P < 0.001), iii) duration of anesthesia (275 ± 75 versus 163 ± 57; P = 0.04) and time to first analgesic requirement (279 ± 87 versus 197 ± 84 min; P = 0.002) were prolonged with decreased visual analog scale scores at this time (30 ± 18 versus 70 ± 24; P < 0.001), and iv) verbal numeric rating scores were decreased at 24 h (1.7 ± 2.2 versus 4.1 ± 3.0; P = 0.002) and 48 h (0.1 ± 0.5 versus 1.5 ± 2.4; P = 0.01) postoperatively. Our findings suggest that in the setting of distal infected tissue surgery under ABPB infected tissues are resistant to anesthesia compared with healthy areas within the same nerve distribution and clonidine added to mepivacaine enhances both anesthesia and postoperative analgesia.

Local Infiltration Analgesia for Postoperative Pain Control following Total Hip Arthroplasty: A Systematic Review

Local infiltration analgesia (LIA) is an analgesic technique that has gained popularity since it was first brought to widespread attention by Kerr and Kohan in 2008. The technique involves the infiltration of a large volume dilute solution of a long-acting local anesthetic agent, often with adjuvants (e.g., epinephrine, ketorolac, an opioid), throughout the wound at the time of surgery. The analgesic effect duration can then be prolonged by the placement of a catheter to the surgical site for postoperative administration of further local anesthetic. The technique has been adopted for use for postoperative analgesia following a range of surgical procedures (orthopedic, general, gynecological, and breast surgeries). The primary objective of this paper was to determine, based on the current evidence, if LIA is superior when compared to no intervention, placebo, and alternative analgesic methods in patients following total hip arthroplasty, in terms of certain outcome measures. The outcomes considered were postoperative analgesia scores, joint function/rehabilitation, and length of hospital stay. Secondary objectives were to review available evidence and current knowledge regarding the pharmacokinetics of local anesthetic and adjuvant drugs when administered in this way and the occurrence of adverse events.

Regional anesthesia techniques for ambulatory orthopedic surgery.

Purpose of review The purpose of this review is to present advances in the use of regional anesthetic techniques in ambulatory orthopedic surgery. New findings regarding the use of both neuraxial anesthesia and peripheral nerve block are discussed. Recent findings Neuraxial anesthesia: The use of short-acting local anesthetic agents such as mepivacaine, 2-chloroprocaine, and articaine permits rapid onset intrathecal anesthesia with early recovery profiles. Advantages and limitations of these agents are discussed. Peripheral nerve block: Peripheral nerve blocks in limb surgery have the potential to transform this patient cohort into a truly ambulatory, self-caring group. Recent trends and evidence regarding the benefits of regional anesthesia techniques are presented. Continuous perineural catheters permit extension of improved perioperative analgesia into the ambulatory home setting. The role and reported safety of continuous catheters are discussed. Summary In summary, shorter acting, neuraxial, local anesthetic agents, specific to the expected duration of surgery, may provide superior recovery profiles in the ambulatory setting. A trend towards more peripheral and selective nerve blocks exists. The infrapatellar block is a promising technique to provide analgesia following knee arthroscopy. Improved analgesia seen in the perioperative period can be safely and effectively extended to the postoperative period with the use of perineural catheters.

A Clinical Evaluation of Block Characteristics Using One Milliliter 2% Lidocaine in Ultrasound-Guided Axillary Brachial Plexus Block

We report onset and duration of ultrasound-guided axillary brachial plexus block using 1 mL of 2% lidocaine with 1:200,000 epinephrine per nerve (total local anesthetic volume 4 mL). Block performance time, block onset time, duration of surgery, and block duration were measured. Seventeen consecutive patients were recruited. The mean (SD) block performance and onset times were 271 (67.9) seconds and 9.7 (3.7) minutes, respectively. Block duration was 160.8 (30.7) minutes. All operations were performed using regional anesthesia alone. The duration of anesthesia obtained is sufficient for most ambulatory hand surgery.

Adding a selective obturator nerve block to the parasacral sciatic nerve block: an evaluation.

Our aim was to objectively evaluate the efficacy of obturator nerve anesthesia after a parasacral block. Patients scheduled for knee surgery had a baseline adductor strength evaluation. After a parasacral block with 30 mL 0.75% ropivacaine, sensory deficit in the sciatic distribution (temperature discrimination) and adductor strength were assessed at 5-min intervals. Patients with an incomplete sensory block (defined as a temperature discrimination score of less than 2 in the 3 cutaneous distributions of the sciatic nerve tested) 30 min after the parasacral block were excluded from the study. Subsequently, a selective obturator block was performed with 7 mL 0.75% ropivacaine and adductor strength was reassessed at 5 min intervals for 15 min. Finally, a femoral block was performed using 10 mL 0.75% ropivacaine. Patient discomfort level during each block was assessed using a visual analog scale (VAS). Thirty-one patients completed the study. Five patients were excluded as a result of inadequate sensory block in the sciatic distribution 30 min after the parasacral block (success rate of 89%). Thirty min after the parasacral block, adductor strength decreased by 11.3% ± 7% compared with baseline (85 ± 24 versus 97 ± 28 mm Hg, P = 0.002). Fifteen min after the obturator nerve block, adductor muscle strength decreased by an additional 69% ± 7% (16.6 ± 15 versus 85 ± 24 mm Hg, P < 0.0001). VAS scores were similar for all blocks (26 ± 19, 28 ± 24, and 27 ± 19 mm for parasacral, obturator, and femoral respectively). Four parasacral blocks were simulated in 2 fresh cadavers using 30 mL of colored latex solution. The spread of the die in relation to the obturator nerve was assessed. Injection of 30 mL colored latex into cadavers resulted in spread of the injectate restricted to the sacral plexus. These findings demonstrate the unreliability of parasacral block to achieve anesthesia of the obturator nerve. A selective obturator block should be considered in the clinical setting when this is desirable.

Proactive error analysis of ultrasound-guided axillary brachial plexus block performance.

Background: Detailed description of the tasks anesthetists undertake during the performance of a complex procedure, such as ultrasound-guided peripheral nerve blockade, allows elements that are vulnerable to human error to be identified. We have applied 3 task analysis tools to one such procedure, namely, ultrasound-guided axillary brachial plexus blockade, with the intention that the results may form a basis to enhance training and performance of the procedure. Methods: A hierarchical task analysis of the procedure was performed with subsequent analysis using systematic human error reduction and prediction approach (SHERPA). Failure modes, effects, and criticality analysis was applied to the output of our SHERPA analysis to provide a definitive hierarchy to the error analysis. Results: Hierarchical task analysis identified 256 tasks associated with the performance of ultrasound-guided axillary brachial plexus blockade. Two hundred twelve proposed errors were analyzed using SHERPA. Failure modes, effects, and criticality analysis methodology was applied to the output of SHERPA analysis to prioritize 20 errors. Conclusions: This study presents a formal analysis of (i) the specific tasks that might be associated with the safe and effective performance of the procedure and (ii) the most critical errors likely to occur as trainees learn to perform the procedure. Potential applications of these data include curricular development and the design of tools to teach and assess block performance.

Conventional Landmark-Guided Midline Versus Preprocedure Ultrasound-Guided Paramedian Techniques in Spinal Anesthesia.

BACKGROUND: Multiple passes and attempts while administering spinal anesthesia are associated with a greater incidence of postdural puncture headache, paraesthesia, and spinal hematoma. We hypothesized that the routine use of a preprocedural ultrasound-guided paramedian technique for spinal anesthesia would reduce the number of passes required to achieve entry into the subarachnoid space when compared with the conventional landmark-guided midline approach. METHODS: One hundred consenting patients scheduled for elective total joint replacements (hip and knee) were randomized into group C (conventional) and group P (preprocedural ultrasound-guided paramedian technique) with 50 in each group. The patients were blinded to the study group. All spinal anesthetics were administered by a consultant anesthesiologist. In group C, spinal anesthetic was done via the midline approach using clinically palpated landmarks. In group P, a preprocedural ultrasound scan was used to mark the paramedian insertion site, and spinal anesthetic was performed via the paramedian approach. RESULTS: The average number of passes (defined as the number of forward advancements of the spinal needle in a given interspinous space, i.e., withdrawal and redirection of spinal needle without exiting the skin) in group P was approximately 0.34 times that in group C, a difference that was statistically significant (P = 0.01). Similarly, the average number of attempts (defined as the number of times the spinal needle was withdrawn from the skin and reinserted) in group P was approximately 0.25 times that of group C (P = 0.0021). In group P, on an average, it took 81.5 (99% confidence interval, 68.4–97 seconds) seconds longer to identify the landmarks than in group C (P = 0.0002). All other parameters, including grading of palpated landmarks, time taken for spinal anesthetic injection, periprocedural pain scores, periprocedural patient discomfort visual analog scale score, conversion to general anesthetic, paresthesia, and radicular pain during needle insertion, were similar between the 2 groups. CONCLUSIONS: Routine use of paramedian spinal anesthesia in the orthopedic patient population undergoing joint replacement surgery, guided by preprocedure ultrasound examination, significantly decreases the number of passes and attempts needed to enter the subarachnoid space.

Local anesthetic dose and volume used in ultrasound-guided peripheral nerve blockade.

In 1978, Drs La Grange, Foster, and Pretorius were the first to describe the use of Doppler ultrasound to identify the third part of the subclavian artery during the performance of supraclavicular brachial plexus block. In their report, they described vascular echolocation using an auditory signal from Doppler ultrasound, and declared the resultant brachial plexus block highly successful and safer than conventional approaches. Three years later in 1981, Drs Abramowitz and Cohen described the first use of Doppler ultrasound to identify the axillary artery, thereby aiding in the performance of an axillary brachial plexus block for upper limb surgery. Despite the availability of B-mode ultrasound imaging, visual guidance was not used at this point in the evolution of ultrasound-assisted peripheral nerve block, favoring auditory signals received from hand-held Doppler ultrasound. It was not until 1989 that images of local anesthetic spread around the axillary brachial plexus were reported. This report heralded an era of ultrasonographic visualization of neural structures and perineural local anesthetics in the performance of peripheral nerve block.

Ultrasound guidance, a win-win approach to peripheral nerve blockade.

Purpose of review The objective of the current review is to examine the likelihood of improved safety in peripheral nerve blockade attributable to ultrasound guidance. Recent findings With ultrasound guidance, a 10-fold reduction in the incidence of local anesthetic systemic toxicity as well as a tendency toward less long-term neuropathies are shown. Summary Ultrasound is clearly superior to other techniques with the aim of achieving maximum efficacy with minimum risk: a win-win approach.