American Society of Anesthesiologists' physical status system: a multicentre Francophone study to analyse reasons for classification disagreement.

CONTEXT: Variability of American Society of Anesthesiologists' (ASA) physical status scores attributed to the same patient by multiple physicians has been reported in several studies. In these studies, the population was limited and diseases that induced disagreement were not analysed. OBJECTIVES: To evaluate the reproducibility of ASA physical status assessment on a large population, as used in current practice before scheduled surgery. DESIGN: Multicentre, randomised, blinded cross-over observational study. METHODS: During a 2-week period in nine institutions, ASA physical status and details of assessment performed routinely by anaesthesiologists for patients who underwent elective surgery were recorded. Records were blinded (including ASA physical status) by an independent statistical division and returned randomly to one of the nine centres for reassessment by accredited specialist anaesthesiologists. MAIN OUTCOME MEASURES: The level of agreement between the two measurements of the ASA physical status was calculated by using the weighted Kappa coefficient. RESULTS: During the study period, 1554 anaesthesia records were collected and 197 were excluded from analysis because of missing data. After the initial evaluation, the distribution of ASA physical status grades was as follows: ASA 1, 571; ASA 2, 591; ASA 3, 177; and ASA 4, 18. After the final evaluation, the distribution of ASA grades was as follows: ASA 1, 583; ASA 2, 520; ASA 3, 223; and ASA 4, 31. Two per cent of the patients had an underestimation of their physical status. The degree of agreement between the two measures evaluated by the weighted Kappa coefficient was 0.53 (0.49-0.56). No difference was observed between public and private institutions. Patients with co-existing diseases, obesity, allergy, sleep apnoea, obstructive lung disease, renal insufficiency and hypertension were least likely to have been graded correctly. CONCLUSION: The degree of agreement between two measures of the ASA physical status grade is moderate and influenced by staff characteristics and the complexity of diseases.

A comparison of the pharmacodynamics and pharmacokinetics of bupivacaine, ropivacaine (with epinephrine) and their equal volume mixtures with lidocaine used for femoral and sciatic nerve blocks: a double-blind randomized study.

BACKGROUND: Mixtures of lidocaine with a long-acting local anesthetic are commonly used for peripheral nerve block. Few data are available regarding the safety, efficacy, or pharmacokinetics of mixtures of local anesthetics. In the current study, we compared the effects of bupivacaine 0.5% or ropivacaine 0.75% alone or in a mixed solution of equal volumes of bupivacaine 0.5% and lidocaine 2% or ropivacaine 0.75% and lidocaine 2% for surgery after femoral-sciatic peripheral nerve block. The primary end point was onset time. METHODS: In a double-blind, randomized study, 82 adults scheduled for lower limb surgery received a sciatic (20 mL) and femoral (20 mL) peripheral nerve block with 0.5% bupivacaine (200 mg), a mixture of 0.5% bupivacaine 20 mL (100 mg) with 2% lidocaine (400 mg), 0.75% ropivacaine (300 mg) or a mixture of 0.75% ropivacaine 20 mL (150 mg) with 2% lidocaine (400 mg). Each solution contained epinephrine 1:200,000. Times to perform blocks, onset times (end of injection to complete sensory and motor block), duration of sensory and motor block, and morphine consumption via IV patient-controlled analgesia were compared. Venous blood samples of 5 mL were collected for determination of drug concentration at 0, 5, 15, 30, 45, 60, and 90 min after placement of the block. RESULTS: Patient demographics and surgical times were similar for all four groups. Sciatic onset times (sensory and motor block) were reduced by combining lidocaine with the long-acting local anesthetic. The onset of bupivacaine-lidocaine was 16 +/- 9 min versus 28 +/- 12 min for bupivacaine alone. The onset of ropivacaine-lidocaine was 16 +/- 12 min versus 23 +/- 12 for ropivacaine alone. Sensory blocks were complete for all patients within 40 min for those receiving bupivacaine-lidocaine versus 60 min for those receiving bupivacaine alone and 30 min for those receiving ropivacaine-lidocaine versus 40 min for those receiving ropivacaine alone (P < 0.05). Duration of sensory and motor block was significantly shorter in mixture groups. There was no difference among groups for visual analog scale pain scores and morphine consumption during the 48 h postoperative period, except for bupivacaine alone (median: 9 mg) versus bupivacaine-lidocaine mixture (15 mg), P < 0.01. There was no difference in the incidence of adverse events among groups. Plasma concentrations of bupivacaine and ropivacaine were higher, and remained elevated longer, in patients who received only the long-acting local anesthetic compared to patients who received the mixture of long-acting local anesthetic with lidocaine (P < 0.01). CONCLUSION: Mixtures of long-acting local anesthetics with lidocaine induced faster onset blocks of decreased duration. Whether there is a safety benefit is unclear, as the benefit of a decreased concentration of long-acting local anesthetic may be offset by the presence of a significant plasma concentration of lidocaine.

The Simplified Predictive Intubation Difficulty Score: a new weighted score for difficult airway assessment.

BACKGROUND AND OBJECTIVE: Using the Intubation Difficulty Scale (IDS) more than 5 as a standardized definition of difficult intubation, we propose a new score to predict difficult intubation: the Simplified Predictive Intubation Difficulty Score (SPIDS). METHODS: We prospectively studied 1024 patients scheduled for elective surgery under general anaesthesia. Using bivariate and multivariable analysis, we established risk factors of difficult intubation. Then, we assigned point values to each of the adjusted risk factors, their sum composing the SPIDS. We assessed its predictive accuracy using sensitivity, specificity, positive (PPV) and negative predictive values (NPV), and the area under the receiver operating characteristic (ROC) curve (AUC), and compared it with the corresponding nonweighted score. The optimal predictive level of the SPIDS was determined using ROC curve analysis. RESULTS: We found five adjusted risk factors for IDS more than 5: pathological conditions associated with difficult intubation (malformation of the face, acromegaly, cervical rheumatism, tumours of the airway, and diabetes mellitus), mouth opening less than 3.5 cm, a ratio of patient's height to thyromental distance 25 at least, head and neck movement less than 80 degrees , and Mallampati 2 at least. Sensitivity, specificity, PPV and NPV of the SPIDS were 65, 76, 14 and 97%, respectively. AUC of the SPIDS and the nonweighted score (obtained previously using a stepwise logistic regression) were respectively 0.78 [95% confidence interval (CI) 0.72-0.84] and 0.69 (95% CI 0.64-0.73). The threshold for an optimal predictive level of the SPIDS was above 10 of 55. CONCLUSION: The SPIDS seems easy to perform, and by weighting risk factors of difficult intubation, it could help anaesthesiologists to plan a difficult airway management strategy. A value of SPIDS strictly above 10 could encourage the anaesthesiologists to plan for the beginning of the anaesthetic induction with 'alternative' airway devices ready in the operating theatre.

Does sciatic parasacral injection spread to the obturator nerve? An anatomic study.

BACKGROUND: The ability of parasacral sciatic nerve block to provide consistent obturator nerve and perineal blockade remains undetermined. In this anatomic work, we assessed the spread of a colored latex mimicking a parasacral injection, and observed the spread to the obturator nerve and sacral nerve roots. METHODS: Fourteen parasacral injections were performed bilaterally on seven human cadavers. Dissection was performed in two steps. First, the posterior approach confirmed the presence of dye on the sciatic nerve at the level of the piriformis muscle to define the success of the injection. Second, the anterior endopelvic dissection assessed the presence of dye around the pelvic portion of the obturator nerve and on the sacral roots (S1-3). The same score was used for all the nerves, from 0 (total failure) to 3 (total success). For all nerves (sciatic, obturator, sacral roots), a score of 2 or 3 was considered a successful injection. RESULTS: Eleven of 14 injections were considered successful parasacral injections. The three failed injections were excluded from further analysis. One was intravascular and two (same cadaver) in the gluteal muscles were too superficial. Of the 11 successful injections, 9 (82%) were scored as providing the spread of latex to both the obturator nerve and to the sacral roots. CONCLUSION: We conclude from this anatomical study that successful parasacral injection consistently spreads to the pelvic portion of the obturator nerve and to the sacral roots. Therefore, parasacral block should theoretically provide obturator and perineal blockade, and eliminate the need for systematic separate obturator nerve block. These results must be confirmed by further clinical studies.

A comparison of mepivacaine versus lidocaine for episcleral (sub-tenon's) block for cataract surgery in an ambulatory setting.

BACKGROUND AND OBJECTIVES: For eye surgery, motor block is still often requested by the surgeon. For cataract surgery, rapid block resolution allows eyelids to move and allows eye-patch removal. Therefore, short-duration block is useful in early rehabilitation for ambulatory surgery. Lidocaine is classically assumed to have shorter duration than mepivacaine. Therefore, lidocaine alone might be considered as an alternative to mepivacaine. METHODS: In this randomized, double-blind study, we compared mepivacaine 2% (n = 22) and lidocaine 2% (n = 25) in 47 patients who received episcleral (sub-Tenon's) block for cataract surgery. Akinesia score was measured 1, 5, 10, and 15 minutes and 1, 2, 4, and 6 hours after the end of injection. Primary outcome was block duration (time from injection to full recovery). Secondary outcomes were time to block onset and best akinesia score for each patient. Complications were recorded. RESULTS: The 2 groups were similar for demographic and anesthetic features. We observed no significant difference between mepivacaine and lidocaine in terms of onset, quality of akinesia, and block duration. One case of ocular hypertonia and 1 case of strabismus were observed in the lidocaine group, which could be imputed to hyaluronidase unavailability during the study period or to increased lidocaine myotoxicity. CONCLUSIONS: We found no argument to favor lidocaine over mepivacaine in episcleral (sub-Tenon's) eye block, especially in terms of motor-block duration.

Parasacral approach to block the sciatic nerve: a 400-case survey.

BACKGROUND AND OBJECTIVES: Parasacral sciatic nerve block has been shown to be easy to perform, but studies reported to date involve a total of only 155 patients. The aim of this study was to assess the efficacy of parasacral sciatic nerve block in a larger group of patients. METHODS: Four hundred consecutive parasacral blocks were evaluated prospectively. The level of expertise of the practitioner, the time to perform the block, the lowest current intensity of nerve stimulation, the injected volume, the onset time, the success or failure of the block, and complications were recorded. RESULTS: The time required to perform the block was 7 +/- 5 minutes. The lowest stimulation-current intensity was 0.4 +/- 0.1 mA, and the injected volume was 27 +/- 4 mL. The onset time was 13 +/- 7 minutes for both motor and sensory block in all nerve distributions. The success rate was 94% (376 of 400 cases). Nine supplemental injections were performed successfully, thus increasing the success rate to 96%. General anesthesia or heavy sedation was performed in 15 cases (3.8%). There was no difference in failure rate between more experienced and less experienced anesthesiologists. CONCLUSIONS: In this prospective 400-case study, we confirmed previous findings that the parasacral approach is effective, easy to perform, and easy to teach, even when performed by relatively inexperienced physicians. The parasacral approach is, therefore, an effective alternative to other approaches of sciatic nerve blockade.

Anaesthesia for cataract surgery.

Cataract surgery is the most frequent surgical procedure requiring anaesthesia in developed countries. It is performed mainly in elderly patients, who present with many coexisting diseases that induce subsequent hazards from general anaesthesia. Cataract anaesthesia is performed following various techniques of regional anaesthesia, which are detailed in this review. Needle block carries a low but real risk of complications, mainly because of needle misplacement. Correct teaching and training are mandatory to prevent complications. The main patient risk factor for inadvertent globe perforation is the presence of a myopic staphyloma. Retrobulbar block has been progressively phased out and replaced by peribulbar block, sub-Tenon's block (STB) or topical anaesthesia (TA). The requirement for very deep block with total akinesia has greatly decreased with the use of phacoemulsification for cataract surgery, allowing for use of TA or low-volume STB. However, non-akinesia techniques may give rise to impaired surgical conditions, which have the potential to result in surgical complications. A surgical approach to accessing sub-Tenon's space avoids needle block, but does not totally prevent complications. When deep anaesthesia is required, low-volume STB, performed using either the needle technique or a surgical approach, appears to be the technique of choice in terms of efficacy. Increasing the anaesthetic volume provides reproducible akinesia. Various local anaesthetics may be used, depending on their availability and respective properties. The most useful adjuvant to local anaesthetic is hyaluronidase.

Comparison of 3 intensities of stimulation threshold for brachial plexus blocks at the midhumeral level: a prospective, double-blind, randomized study.

BACKGROUND: We conducted this prospective randomized study to compare the success rate and the onset time between 3 intensities of stimulation threshold (<0.5, 0.5-0.64, and 0.65-0.8 mA) when using a peripheral nerve stimulation at the midhumeral level. METHODS: Sixty-nine adult patients undergoing elective hand surgery were studied. Blocks were performed using conventional nerve stimulation technique. Needle advance began at 2 mA (1 Hz, 0.1 millisecond). When motor response (MR) occurred at less than 0.5 mA, needle position was fixed for "group <0.5 mA." For "group 0.5-0.64 mA," the needle was withdrawn until MR occurred at greater than 0.5 mA and disappeared at less than 0.5 mA. For "group >0.65 mA," the needle was withdrawn until MR occurred at greater than 0.65 mA and disappeared at less than 0.65 mA. For each group, patients received 8 mL of ropivacaine 7.5 mg/mL on the 4 nerves (radial, median, ulnar, and musculocutaneous). Primary end point was the number of failed radial nerve sensory blocks at 30 mins. RESULTS: The time to perform the block was not different between the 3 groups (17 mins [SD, 7 mins] vs 13 mins [SD, 8 mins] and 13 mins [SD, 4 mins], respectively). The time required to obtain a complete sensory block was shorter for the 4 nerves in group <0.5 mA, with a statistical significance for radial and musculocutaneous nerves in group <0.5 mA versus group 0.5-0.64 mA and group >0.65 mA. Patients in group <0.5 mA had a greater success rate for complete sensory radial nerve compared with those of group 0.5-0.64 mA and group >0.65 mA at any interval times between 5 and 30 mins (P = 0.0001). Supplemental local anesthesia was provided for the 3 groups more frequently for the median nerve, with no difference between groups. Group >0.65 mA required 5 general anesthesias (20%) as compared with 1 (4%) in group <0.5 mA (P < 0.05). No adverse event (dysesthesia) occurred after 48 hrs and 45 days. CONCLUSION: We conclude that intensity of stimulation influenced onset time and success rate.

[Case report: bilateral femoral and sciatic regional anesthesia in a polytraumatized patient]. / Etude de cas: Anesthesie locoregionale sciatique et femorale bilaterale chez un polytraumatise.

PURPOSE: To present a case requiring regional anesthesia for both lower limbs, and to highlight the considerations to avoid potential local anesthetic toxicity, as a result of high cumulative doses of local anesthetic in this setting. CLINICAL FEATURES: A 32-yr-old, obese (body mass index = 30.4 kg.m(-2)) woman required urgent, open reduction of bilateral ankle fractures. She also had facial, odontoid and pelvic fractures, and, in view of full stomach considerations, the anesthetic plan was to use regional anesthesia. Bilateral femoral and sciatic nerve blocks were performed, using a combination of ropivacaine and mepivacaine, with a 210-min interval between limbs. Blood samples were drawn 80 and 45 min after the first and second blocks, respectively, to measure plasma concentrations of the local anesthetics. Ropivacaine and mepivacaine concentrations were below reported toxic levels, and the patient underwent surgery successfully, without any symptoms suggestive of local anesthetic toxicity. CONCLUSIONS: Regional anesthetic techniques for the lower limb may require local anesthetic doses approaching toxic levels, especially when bilateral blocks are required. This case indicates that by considering the pharmacokinetic and pharmacodynamic characteristics of each agent, and by timing the blocks properly to minimize peak plasma concentrations, the potential for local anesthetic toxicity can be reduced.

Ophthalmic regional anesthesia: medial canthus episcleral (sub-tenon) single injection block.

BACKGROUND: The purpose of this study was to evaluate the efficacy and safety of episcleral single-injection anesthesia in a large number of patients. METHODS: Over a period of 5 yr, in four institutions, anesthesiologists involved in this prospective study completed a standardized form to evaluate single-injection medial canthus high-volume episcleral anesthesia. The success rate of the block was rated according to an akinesia score. The study parameters included demographic data, surgical procedure, and anesthetic management. All patients were followed up at least until postoperative day 1, and all complications, pain, and discomfort were noted. Statistical analysis was done to assess the risk factors for complications. RESULTS: A total of 2,031 patients were included in the study. The most frequent surgical procedures performed were phacoemulsification and posterior chamber artificial lens implantation (91.0%). A total of 66 complications (3.3%) occurred in 60 patients. One patient had a retrobulbar hemorrhage, and 59 had one or two more minor incidents or pain/discomfort with the procedure. The complications consisted of subconjunctival hematoma (1.3%), ocular hypertonia (0.4%), and chemosis (0.30%). Statistical analysis revealed that inexperience in the technique represented a risk factor for complications. CONCLUSIONS: This is the first survey of a large experience in episcleral single-injection anesthesia, a form of anesthesia that does not preclude sharp-needle complications and does require training. Only one complication occurred among 2,031 patients; however, a larger number of patients is needed to definitively evaluate the safety of episcleral single-injection anesthesia.