Difficult mask ventilation in obese patients: analysis of predictive factors.

BACKGROUND: This study aimed to determine the accuracy of commonly used preoperative difficult airway indices as predictors of difficult mask ventilation (DMV) in obese patients (BMI >30 kg/m2). METHODS: In 309 consecutive obese patients undergoing general surgery, the modified Mallampati test, patient's Height/Thyromental distance ratio, Inter-Incisor Distance, Protruding Mandible (PM), history of Obstructive Sleep Apnea and Neck Circumference (NC) were recorded preoperatively. DMV was defined as Grade 3 mask ventilation (MV) by the Han's scale (MV inadequate, unstable or requiring two practitioners). Data are shown as means±SD or number and proportions. Independent DMV predictors were identified by multivariate analysis. The discriminating capacity of the model (ROC curve area) and adjusted weights for the risk factors (odds ratios) were also determined. RESULTS: BMI averaged 42.5±8.3 kg/m2. DMV was reported in 27 out of 309 patients (8.8%; 95%CI 5.6-11.9%). The multivariate analysis retained NC (OR 1.17; P<0.0001), limited PM (1.99; P=0.046) and Mallampati test (OR 2.12; P=0.009) as risk predictors for DMV. Male gender was also included in the final model (OR 1.87; P=0.06) as biologically important variable albeit the borderline statistical significance. The model yielded a good discriminating capacity (ROC curve 0.85). The four parameters were used to create an unweighted prediction score (ROC curve 0.84) with >2 associated factors as the best discriminating point for DMV. CONCLUSION: Obese patients show increased incidence of DMV with respect to the undifferentiated surgical population. Limited PM, Mallampati test and NC are important DMV predictors.

Posterior psoas vs 3-in-1 approach for lateral femoral cutaneous and obturator nerve block for anterior cruciate ligament repair.

AIM: The aim of this article was to test the hypothesis that the posterior psoas compartment approach to the lumbar plexus help to achieve better blockade of the lateral femoral cutaneous and obturator nerves than the classic anterior 3-in-1 femoral nerve block. METHODS: Thirty-six patients who were undergoing anterior cruciate ligament repair were randomly allocated to receive a femoral nerve block using either an anterior 3-in-1 femoral block (group Femoral, N=18) or a posterior psoas compartment approach (group Psoas, N=18) using 30 mL of 1.5% mepivacaine. Successful nerve block was defined as a complete loss of pinprick sensation in the region that is supplied by the lateral femoral cutaneous nerve along with adequate motor block of the obturator nerve 30 minutes after injection. The degree of motor block of the obturator nerve was measured using adduction strength with a mercury sphygmomanometer as previously described by Lang. RESULTS: Thirty minutes after the completion of the block, sensory block of the lateral femoral cutaneous nerve was observed in 14 patients (78%) from the Psoas group and in 3 patients (17%) from the Femoral group (P=0.001). Thirty minutes after the completion of the block, a 119+/-40 mmHg decrease was found in Psoas group, in contrast to the 25+/-22 mmHg decrease found in the Femoral group (P<0.0005). CONCLUSIONS: The posterior psoas compartment approach provides a more reliable block of the lateral femoral cutaneous and obturator nerves than the anterior 3-in-1 approach.

Sciatic nerve block with 0.5% levobupivacaine, 0.75% levobupivacaine or 0.75% ropivacaine: a double-blind, randomized comparison.

BACKGROUND AND OBJECTIVE: This prospective, randomized, double-blind study was conducted to evaluate the onset time and duration of sciatic nerve block produced with 0.5% levobupivacaine, 0.75% levobupivacaine and 0.75% ropivacaine. METHODS: Forty-five healthy patients undergoing hallux valgus repair were randomly allocated to receive sciatic nerve block with levobupivacaine 0.5% (n=15), levobupivacaine 0.75% (n=15) or ropivacaine 0.75% 20 mL (n=15). A femoral nerve block was also performed with mepivacaine 2% 15 mL to cover pain related to the thigh tourniquet. A blinded observer recorded the onset time and duration of sciatic nerve block. RESULTS: The median (range) onset time was 5 (5-40) min with 0.75% levobupivacaine, 30 (5-60) min with 0.5% levobupivacaine and 20 (5-50) min with 0.75% ropivacaine (P = 0.02 and P = 0.12, respectively). Mean (25-75 percentiles) first request for pain medication occurred after 13 (11-14) h with 0.75% ropivacaine, 18 (15-19) h with 0.75% levobupivacaine and 16 (13-20) h with 0.5% levobupivacaine (P = 0.002 and P = 0.002, respectively). Rescue tramadol after surgery was required by three patients in the 0.75% levobupivacaine group, eight patients in the 0.5% levobupivacaine group and nine patients in the 0.75% ropivacaine group (P = 0.05). CONCLUSIONS: We conclude that 0.75% levobupivacaine provides a shorter onset time than 0.5% levobupivacaine and a longer duration of postoperative analgesia than both 0.5% levobupivacaine and 0.75% ropivacaine with reduced need for rescue analgesia after surgery.

Total intravenous anesthesia, spinal anesthesia or combined sciatic-femoral nerve block for outpatient knee arthroscopy.

AIM: The aim of this study was to compare efficacy, efficiency and surgeon's satisfaction of total intravenous anesthesia with propofol and remifentanil with those of spinal or peripheral nerve blocks for outpatient knee arthroscopy. METHODS: One hundred and twenty patients undergoing elective outpatient knee arthroscopy were randomly allocated to receive total intravenous anesthesia with propofol and remifentanil (40), combined sciatic-femoral nerve block (40), or spinal anesthesia (40). Preparation times, surgeon's satisfaction, and discharge times with the 3 anesthesia techniques were measured. Anesthesia-related costs were also compared based on costs of drugs, disposable materials, and anesthesia and nurse staff. RESULTS: Preparation time was 13 min (8-22 min) with general anesthesia, 15 min (5-30 min) with spinal anesthesia and 15 min (5-25 min) with sciatic-femoral blocks (p=0.006). Surgeon's satisfaction was similar in the 3 groups, but 17 patients receiving peripheral nerve block (42%) and 12 receiving spinal anesthesia (30%) by-passed the postanesthesia care unit after surgery as compared with only 2 general anesthesia patients (5%) (p=0.01). Discharge from the postanesthesia care unit required 5 min (5-20 min) after peripheral block as compared with 15 min (5-25 min) with spinal and 15 min (5-80 min) with general anesthesia (p=0.005); however, stay in the Day-Surgery Unit was shorter after general anesthesia [170 (100-400) min] than peripheral [265 (110-485) min] or spinal blocks [230 (95-800) min] (p=0.026). Urinary retention was reported in 3 spinal patients only (8%) (p=0.03). CONCLUSION: Regional anesthesia techniques reduce the rate of admission and the duration of stay in the postanesthesia care unit as compared with general anesthesia. Peripheral rather than spinal nerve blocks should be preferred to minimise the risk for urinary retention.

Randomized comparison between sevoflurane anaesthesia and unilateral spinal anaesthesia in elderly patients undergoing orthopaedic surgery.

BACKGROUND AND OBJECTIVE: This prospective, randomized study was conducted to compare unilateral spinal block using small doses of hyperbaric bupivacaine and single-agent anaesthesia with sevoflurane in elderly patients undergoing hip surgery. METHODS: Thirty patients (> 65 yr) undergoing hip fracture repair were randomly allocated to receive unilateral spinal anaesthesia with hyperbaric bupivacaine 7.5 mg 0.5% (Group Spinal, n = 15) or volatile induction and maintenance anaesthesia with sevoflurane (Group SEVO, n = 15). General anaesthesia was induced by increasing the inspired concentration to 5%. A laryngeal mask airway was placed without muscle relaxants, and the end-tidal concentrations of sevoflurane were adjusted to maintain cardiovascular stability. Hypotension (decrease in systolic arterial pressure > 20% from baseline), hypertension or bradycardia (heart rate < 50 beats min(-1)) requiring treatment, and the length of stay in the postanaesthesia care unit was recorded. Cognitive functions were evaluated the previous day, and 1 and 7 days after surgery with the Mini Mental State Examination test. RESULTS: Hypotension occurred in seven patients of Group Spinal (46%) and in 12 patients of Group SEVO (80%) (P = 0.05). Phenylephrine was required to control hypotension in three spinal patients (21%) and four SEVO patients (26%) (n.s.). SEVO patients had lower heart rates than spinal patients from 15 to 60 min after anaesthesia induction (P = 0.01). Bradycardia was observed in three SEVO patients (22%). Discharge from the postanaesthesia care unit required 15 (range 5-30) min in Group Spinal and 55 (15-80) min in Group SEVO (P = 0.0005). Eight patients in Group Spinal (53%) and nine patients in Group SEVO (60%) showed cognitive decline (Mini Mental State Examination test decreased > or = 2 points from baseline) 24 h after surgery (n.s.). Seven days after surgery, confusion was still present in one patient of Group Spinal (6%) and in three patients of Group SEVO (20%) (n.s.). CONCLUSIONS: In elderly patients undergoing hemiarthroplasty of the hip, induction and maintenance with sevoflurane provide a rapid emergence from anaesthesia without more depression of postoperative cognitive function compared with unilateral spinal anaesthesia. This technique represents an attractive option when patient refusal, lack of adequate co-operation or concomitant anticoagulant therapy contraindicate the use of spinal anaesthesia.

Lidocaine versus ropivacaine for continuous interscalene brachial plexus block after open shoulder surgery.

BACKGROUND: This study compared the postoperative infusion of 1% lidocaine and 0.2% ropivacaine for continuous interscalene analgesia in patients undergoing open shoulder surgery. METHODS: Forty patients undergoing open shoulder surgery received an interscalene brachial plexus block with 30 ml of either 1.5% lidocaine (n = 20) or 0.5% ropivacaine (n = 20), followed by a continuous patient-controlled interscalene analgesia with 1% lidocaine or 0.2% ropivacaine, respectively. A blinded observer recorded the quality of analgesia and recovery of motor function during the first 24 h of infusion. RESULTS: Onset of the block occurred after 7.5 (5-40) min with lidocaine and 30 (10-60) min with ropivacaine (P = 0.0005). Postoperative pain intensity was higher with lidocaine than ropivacaine for the first 8 h of infusion. The ratio between boluses given and demanded from the pump was 0.5 (0.13-0.7) with lidocaine and 0.7 (0.4-1.0) with ropivacaine (P = 0.005). Rescue IV tramadol was required during the first 24 h of infusion by 16 patients of the lidocaine group (84%) and eight patients of the ropivacaine group (46%) (P = 0.05). At the 16 h and 24 h observation times a larger proportion of patients receiving ropivacaine had complete regression of motor block (70% and 95%) than patients receiving lidocaine (50% and 55%) (P = 0.05 and P = 0.013, respectively). CONCLUSIONS: Although 1% lidocaine can be effectively used for postoperative patient-controlled interscalene analgesia, 0.2% ropivacaine provides better pain relief and motor function.

Improving postoperative analgesia after axillary brachial plexus anesthesia with 0.75% ropivacaine. A double-blind evaluation of adding clonidine.

BACKGROUND: The aim of this prospective, randomized, double-blind study was to evaluate the effects of adding 1 microg/kg clonidine to 20 ml of ropivacaine 0.75% for axillary brachial plexus anesthesia. METHODS: With Ethical Committee approval and written consent, 30 ASA physical status I-II in-patients, undergoing upper extremity orthopedic procedures were randomly allocated to receive axillary brachial plexus block with 20 ml of 0.75% ropivacaine alone (group ropivacaine, n = 15) or 0.75% ropivacaine + 1 microg/kg clonidine (group ropivacaine-clonidine, n = 15). Nerve blocks were placed using a nerve stimulator with the multiple injection technique (stimulation frequency was 2 Hz; stimulation intensity was decreased to < or = 0.5 mA after each muscular twitch; the anesthetic volume was equally divided among arm flexion, arm extension, wrist flexion, and thumb adduction). A blinded observer recorded the time required to achieve surgical block [loss of pinprick sensation in the innervation areas of the hand (C6-C8) with concomitant inability to move the wrist and hand] and first analgesic request. RESULTS: No differences in demography, degree of sedation, peripheral oxygen saturation, and hemodynamic variables were observed between the two groups. Readiness for surgery required 15 min (5-36 min) with 0.75% ropivacaine and 20 min (5-30 min) with the ropivacaine-clonidine mixture. The degree of pain measured at first analgesic request, and consumption of postoperative analgesics were similar in the two groups; while first postoperative analgesic request occurred after 13.8 h (25th-75th percentiles: 9.1-13 h) in the ropivacaine group and 15.2 h (25th-75th percentiles: 10.7-16 h) in the ropivacaine-clonidine group (p = 0.04). CONCLUSIONS: Adding 1 microg/kg clonidine to 20 ml of ropivacaine 0.75% for axillary brachial plexus anesthesia provided a 3 h delay in first analgesic request postoperatively, without clinically relevant effects on the degree of sedation and cardiovascular homeostasis.

Small-dose clonidine prolongs postoperative analgesia after sciatic-femoral nerve block with 0.75% ropivacaine for foot surgery.

UNLABELLED: To evaluate the effects of adding small-dose clonidine to 0.75% ropivacaine during peripheral nerve blocks, 30 ASA physical status I and II patients undergoing hallux valgus repair under combined sciatic-femoral nerve block were randomly allocated in a double-blinded fashion to receive block placement with 30 mL of either 0.75% ropivacaine alone (group Ropivacaine, n = 15) or 0.75% ropivacaine plus 1 microg/kg clonidine (group Ropivacaine-Clonidine, n = 15). Hemodynamic variables, oxygen saturation, and levels of sedation, as well as the time required to achieve surgical block and time to first analgesic request, were recorded by a blinded observer. Time to surgical blockade required 10 min in both groups. Patients in the Ropivacaine-Clonidine group were more sedated than patients in the Ropivacaine group only 10 min after block placement. No differences in oxygen saturation and hemodynamic variables, degree of pain measured at first analgesic request, and consumption of postoperative analgesics were observed between the two groups. The mean time from block placement to first request for pain medication was shorter in group Ropivacaine (13.7 h; 25th-75th percentiles: 11. 8-14.5 h) than in group Ropivacaine-Clonidine (16.8 h; 25th-75th percentiles: 13.5-17.8 h) (P = 0.038). We conclude that adding 1 microg/kg clonidine to 0.75% ropivacaine provided a 3-h delay in first request for pain medication after hallux valgus repair, with no clinically relevant side effects. IMPLICATIONS: This prospective, randomized, double-blinded study demonstrated that, when providing combined sciatic-femoral nerve block for hallux valgus repair, the addition of 1 microg/kg clonidine to 0.75% ropivacaine prolongs the duration of postoperative analgesia by 3 h, with only a slight and short-lived increase in the degree of sedation and no hemodynamic adverse effects.

The effects of the single or multiple injection technique on the onset time of femoral nerve blocks with 0.75% ropivacaine.

UNLABELLED: We evaluated the effect of the injection technique on the onset time and efficacy of femoral nerve block performed with 0.75% ropivacaine. A total of 30 patients undergoing arthroscopic knee surgery were randomly allocated to receive femoral nerve blockade with 0.75% ropivacaine by using either a single injection (Single group, n = 15) or multiple injection (Multiple group, n = 15). Nerve blocks were placed by using a short-beveled, Teflon-coated, stimulating needle. The stimulation frequency was set at 2 Hz, and the intensity of stimulating current, initially set at 1 mA, was gradually decreased to <0.5 mA after each muscular twitch was observed. In the Single group, 12 mL of 0.75% ropivacaine was slowly injected, as soon as the first muscular twitch was observed. In the Multiple group, the stimulating needle was inserted and redirected, eliciting each of the following muscular twitches: contraction of vastus medialis, vastus intermedius, and vastus lateralis. At each muscular twitch, 4 mL of the study solution was injected. Placing the block required 4.2 +/- 1.7 min (median, 5 min; range, 2-8 min) in the Multiple group and 3.4 +/- 2.2 min (median, 3 min; range, 1-5 min) in the Single group (P = 0.02). Onset of nerve block (complete loss of pinprick sensation in the femoral nerve distribution with concomitant inability to elevate the leg from the operating table with the hip flexed) required 10 +/- 3.7 min in the Multiple group (median, 10 min; range, 5-20 min) and 30 +/- 11 min in the Single group (median, 30 min; range, 10-50 min) (P < 0.0005). Propofol sedation was never required to complete surgery; although 0.1 mg fentanyl at trocar insertion was required in two patients of the Multiple group (13%) and nine patients of the Single group (60%) (P = 0.02). We conclude that searching for multiple muscular twitches shortened the onset time and improved the quality of femoral nerve block performed with small volumes of 0.75% ropivacaine. IMPLICATIONS: This prospective, randomized, blinded study was conducted to evaluate the effect of searching for multiple muscular twitches when performing femoral nerve block with small volumes of 0. 75% ropivacaine. Our results demonstrated that multiple injections markedly shortened the onset time and improved the quality of nerve blockade. This technique-related effect must be carefully considered when different clinical studies evaluating the use of new local anesthetic solutions for peripheral nerve blocks are compared.

Lightwand intubation does not reduce the increase in intraocular pressure associated with tracheal intubation.

OBJECTIVE: To evaluate the changes in hemodynamic variables and intraocular pressure (IOP) after tracheal intubation using either lightwand or direct-vision laryngoscopy techniques. DESIGN: Prospective, randomized study. SETTING: Inpatient anesthesia at a University Anesthesia Department. PATIENTS: 50 normotensive, ASA physical status I and II patients, without ocular or cardiovascular diseases, and with a Mallampati score no greater than 2. INTERVENTIONS: After intravenous (i.v.) midazolam premedication (0.05 mg.kg-1), general anesthesia was induced with fentanyl (1 microgram.g-1) and thiopental sodium (5 mg.g-1) followed by vecuronium bromide (0.1 mg.g-1), then patients were randomly allocated to receive either the lightwand (Trachlight, n = 25) or direct-vision laryngoscopy (Laryngoscopy, n = 25) intubating techniques. General anesthesia was maintained with 1% isoflurane and 60% nitrous oxide in oxygen mixture for 5 minutes. MEASUREMENTS AND MAIN RESULTS: Baseline hemodynamic variables were recorded 10 minutes after i.v. premedication, and then every minute after tracheal intubation. Intraocular pressure measurements were performed by means of a computerized indentation tonometer after general anesthesia induction and then 1 and 5 minutes after tracheal intubation. In both groups, mean arterial blood pressure and heart rate increased from baseline, without differences between the two groups. One minute after intubation, IOP increased in both groups: the mean percentage increase was 32% in the Laryngoscopy group and 16% in the Trachlight group. However, this difference was not statistically significant. Five minutes after intubation, IOP decreased to baseline values in both groups. CONCLUSION: We conclude that in healthy patients without ocular disease, using a lightwand intubating technique does not reduce the hemodynamic responses and increase in IOP associated with tracheal intubation as compared with conventional direct-vision laryngoscopy.

Frequency of hypotension during conventional or asymmetric hyperbaric spinal block.

BACKGROUND AND OBJECTIVES: The purpose of this randomized, double-blind study was to evaluate if use of an asymmetric spinal block affects the incidence of hypotension during spinal anesthesia. METHODS: With Ethical Committee approval and patient consent, 120 patients undergoing lower limb surgery were placed in the lateral position with the side to be operated on dependent, and received 8 mg 0.5% hyperbaric bupivacaine through a 25-gauge Whitacre spinal needle. Patients were randomized to one of two groups: (a) local anesthetic was injected with barbotage through a cranially directed needle orifice, then patients were immediately turned to supine (conventional, n = 60); (b) local anesthetic was injected without barbotage with the needle orifice turned toward the dependent side, then the lateral position was maintained for 15 minutes (unilateral, n = 60). A blind observer recorded noninvasive hemodynamic variables, as well as loss of cold and pinprick sensation and motor block on both sides. RESULTS: In the unilateral group, 31 patients (52%) showed a unilateral loss of cold sensation and 48 patients (80%) had no motor block on the nondependent side for the duration of the study, whereas all conventional patients had bilateral distribution of spinal block (P < .0001). The onset time and two-segment regression of sensory block on the dependent side were more rapid in the conventional group (18 +/- 7 minutes and 60 +/- 18 minutes) than in the unilateral group (22 +/- 8 minutes and 67 +/- 19 minutes) (P < .05 and P < .05, respectively). The incidence of hypotension (SAP decrease >30% from baseline) was higher in the conventional (22.4%) than unilateral group (5%) (P < .01). The maximum percentage changes from baseline values of systolic arterial blood pressure and heart rate were greater in conventional group (-28% +/- 16% and -19% +/- 10%) than in unilateral group (-8% +/- 16% and -12% +/- 18%) (P < .0001 and P < .01, respectively). CONCLUSIONS: Achieving an asymmetric distribution of spinal block by injecting a small dose of 0.5% hyperbaric bupivacaine through a Whitacre spinal needle into patients placed in the lateral position for 15 min reduces the incidence of hypotension during spinal anesthesia.

Effects of speed of intrathecal injection on unilateral spinal block by 1% hyperbaric bupivacaine. A randomized, double-blind study.

BACKGROUND: To evaluate if the speed of intrathecal injection affects the lateral distribution of spinal block during unilateral spinal anaesthesia with 1% hyperbaric bupivacaine. DESIGN: prospective, randomized, double-blind study. SETTING: anaesthesia Department at a University Hospital. PATIENTS: 30 ASA physical status I-II patients, scheduled for elective orthopedic surgery involving one lower limb only (ankle and foot surgery). INTERVENTIONS: after placing the patients in the lateral decubitus position with the site to be operated on dependent, dural puncture was performed at L3-L4 interspace using a 25-Gauge Whitacre spinal needle. After the needle hole had been turned toward the dependent side, patients were randomized to receive 8 mg of 1% hyperbaric bupivacaine injected over either 40 sec (Group SLOW, n = 15) or 3 sec (Group FAST, n = 15). The lateral position was maintained for 15 min. MEASUREMENTS: a blind observer evaluated the evolution of sensory (pinprick test) and motor (modified Bromage scale) blocks on both the dependent and nondependent sides until the regression of motor block by one degree. RESULTS: No differences in the maximal sensory level on both the dependent and nondependent sides were observed in the two groups. Unilateral sensory block was onserved in 6 patients in group SLOW (40%) and in 5 patients in group FAST (33%), (p = not significant[NS]. Unilateral motor block was observed in 9 patients in group SLOW (60%) and in 10 patients in group FAST (66%) (NS). CONCLUSIONS: Extremely reduced speeds of intrathecal injection did not improve the lateral distribution of spinal block when injecting 8 mg of 1% hyperbaric bupivacaine through a pencil-point directional spinal needle.

Pulmonary function changes after interscalene brachial plexus anesthesia with 0.5% and 0.75% ropivacaine: a double-blinded comparison with 2% mepivacaine.

UNLABELLED: The purpose of this investigation was to compare, in a prospective, double-blinded fashion, 0.5% and 0.75% ropivacaine with 2% mepivacaine to determine their effects on respiratory function during interscalene brachial plexus (IBP) anesthesia. With ethical committee approval and written, informed consent, 30 healthy patients presenting for elective shoulder capsuloplastic or acromioplastic procedures were randomized to receive IBP anesthesia by 20 mL of either 0.5% ropivacaine (n = 10), 0.75% ropivacaine (n = 10), or 2% mepivacaine (n = 10). Block onset time, pulmonary function variables, ipsilateral hemidiaphragmatic motion (ultrasonographic evaluation), and first requirement of postoperative analgesic were evaluated. Surgical anesthesia (loss of pinprick sensation from C4 to C7 and motor block of the shoulder joint) was achieved later with 0.5% ropivacaine than with either 0.75% ropivacaine or 2% mepivacaine (P < 0.05), whereas the first pain medication was requested later with both ropivacaine concentrations than with mepivacaine (P < 0.0005). No differences in quality of the block or patient acceptance were observed in the three groups. All 30 patients had ipsilateral hemidiaphragmatic paresis and large mean decreases in forced vital capacity (ropivacaine 0.5%: 40% +/- 17%, ropivacaine 0.75%: 41% +/- 22%, mepivacaine 2%: 39% +/- 21%) and forced expiratory volume at 1 s (ropivacaine 0.5%: 30% +/- 19%, ropivacaine 0.75%: 38% +/- 26%, mepivacaine 2%: 40% +/- 10%). We conclude that, when performing IBP anesthesia, 0.5% ropivacaine does not decrease the incidence of ipsilateral paresis of the hemidiaphragm compared with 0.75% ropivacaine and 2% mepivacaine. IMPLICATIONS: During the first 30 min after placing interscalene brachial plexus anesthesia, 0.5% ropivacaine does not provide clinically relevant advantages in terms of pulmonary function changes compared with either 0.75% ropivacaine or 2% mepivacaine. However, 0.75% ropivacaine allows a short onset, similar to that of mepivacaine, with long postoperative analgesia.

Interscalene brachial plexus anaesthesia with 0.5%, 0.75% or 1% ropivacaine: a double-blind comparison with 2% mepivacaine.

We have compared interscalene brachial plexus block performed with ropivacaine or mepivacaine in 60 healthy patients undergoing elective shoulder surgery. Patients were allocated randomly to receive interscalene brachial plexus anaesthesia with 20 ml of 0.5% ropivacaine (n = 15), 0.75% ropivacaine (n = 15), 1% ropivacaine (n = 15) or 2% mepivacaine (n = 15). Readiness for surgery (loss of pinprick sensation from C4 to C7 and inability to elevate the limb from the bed) was achieved sooner with 1% ropivacaine (mean 10 (SD 5) min) than with 0.5% ropivacaine (22 (7) min) (P < 0.001) or 2% mepivacaine (18 (9) min) (P < 0.02). Postoperative analgesia was similar with the three ropivacaine concentrations (11.5 (5) h, 10.7 (2) h and 10 (2.4) h with 0.5%, 0.75% and 1% concentrations, respectively) and nearly two-fold longer compared with 2% mepivacaine (5.1 (2.7) h) (P < 0.001).

Do we need new supraglottic devices? Clinical appraisal of the cuffed oropharyngeal airway (COPA)

BACKGROUND: The laryngeal mask airway (LMA) has been widely studied for both conventional and nonconventional uses, while the literature on the cuffed oropharyngeal airway (COPA) is still limited. The purpose of this manuscript was to review the initial appraisal of efficacy, safety, effects on hemodynamics and respiratory function, induction agents and drug requirements of this new supraglottic device. METHODS: We reviewed main results of studies recently published on peer reviewed journals concerning the clinical uses of COPA. RESULTS: When used in healthy adults undergoing general anesthesia for routine minor procedures, the COPA and LMA are substantially equivalent. The LMA is associated with a higher first-time placement rate and fewer manipulations during usage, but the incidence of airway untoward events during COPA anesthesia is equivalent to that reported when using an LMA. The quality of breathing and capnography during COPA ventilation is similar to that provided by the LMA ventilation, with clinically relevant decrease in the physiological deadspace/tidal volume ratio and arterial to end-tidal CO2 tension difference compared with facemask ventilation. In selected patients without risk factors for regurgitation of gastric content, positive-pressure ventilation is similarly successful and safe with the COPA as with the LMA. The COPA seems to be less stimulating than LMA because it has been demonstrated to cause a lower incidence of pharyngeal trauma and sore throat in the immediate postoperative period, requires shorter exposure to an inhalational anesthetic and lower concentrations of propofol to be successfully placed, and is associated with lower effects on the patient's hemodynamic homeostasis than LMA. CONCLUSIONS: More extensive clinical evaluations should be advocated to better understand the risk/benefit ratio of this new supraglottic device; however, it may be concluded that in healthy adults receiving general anesthesia for short procedures the COPA allows for an effective and safe control of the patient's airway and ventilation.

Does speed of intrathecal injection affect the distribution of 0.5% hyperbaric bupivacaine?

We have evaluated the influence of speed of intrathecal injection on lateral distribution of 0.5% hyperbaric bupivacaine. We studied 60 patients undergoing lower limb surgery who were placed in the lateral position with the operative side in the dependent position. After dural puncture (25-gauge Whitacre spinal needle), the needle aperture was turned towards the dependent side and 0.5% hyperbaric bupivacaine 8 mg was injected randomly at a rate of 0.02 ml s-1 (group slow, n = 30) or 0.25 ml s-1 (group fast, n = 30). Lateral position was maintained for 15 min while a blinded observer recorded loss of pinprick sensation and degree of motor block on both surgical and non-surgical sides. There were no differences between the groups. Forty-five minutes after patients were turned to the supine position, spinal anaesthesia was unilateral in 17 patients in group slow (56%) and in 13 patients in group fast (43%). We conclude that using extremely low speeds for intrathecal injection were not clinically advantageous in obtaining unilateral spinal anaesthesia.

Block distribution and cardiovascular effects of unilateral spinal anaesthesia by 0.5% hyperbaric bupivacaine. A clinical comparison with bilateral spinal block.

BACKGROUND: A low dose of hyperbaric local anaesthetic solution, pencil point needle and slow speed of intrathecal injection have been reported to obtain a unilateral distribution of spinal anaesthesia. This should also minimize cardiovascular effects of spinal block. The aim of this prospective, randomized, parallel group study was to evaluate cardiac performance during unilateral subarachnoid block and to compare it with that produced by standard bilateral spinal anaesthesia. METHODS: With Ethic Committee approval and patients' consent we studied 30 ASA I-II patients scheduled for one leg surgery. Dural puncture was performed by 25-G Whitacre needle with patients lying in the lateral position and the side to be operated on dependent. Patients then randomly received 8 mg of 0.5% hyperbaric bupivacaine injected over 80 sec with needle hole orientated towards the dependent side (Unilateral, n = 15), or 15 mg of the same solution injected over 6 sec with needle bevel cranially directed (Control, n = 15). Only patients of the Unilateral group remained in the lateral position for 15 min. Noninvasive Arterial blood pressure, heart rate, stroke volume index and cardiac index were measured before spinal block (baseline) and then at 5, 15, 30 and 45 min; while sensory and motor blocks were evaluated at 15, 30 and 45 min on both sides. RESULTS: Unilateral spinal anaesthesia was observed in 11 patients of the Unilateral group (73%). Three patients of the Control group (20%) required colloids for intraoperative hypotension. Mean arterial blood pressure and heart rate decreased from baseline only in the Control group (p = 0.001 and p = 0.0003 respectively), while heart rate was decreased in Control even when compared to Unilateral group (p = 0.01). The stroke volume index was unchanged in the two groups (p = 0.22), while the cardiac index showed a 15-20% decrease from baseline in Control group (p = 0.001), with a significant decrease at 30 and 45 min when compared to Unilateral (p = 0.01). DISCUSSION: The use of 8 mg of 0.5% hyperbaric bupivacaine slowly injected through a directional needle provided a spinal block relatively restricted to the operative side with minimal effects on cardiovascular homeostasis.

A double-blind study of axillary brachial plexus block by 0.75% ropivacaine or 2% mepivacaine.

Axillary brachial plexus block using 20 mL of 0.75% ropivacaine or 2% mepivacaine was compared in a prospective, randomized, double-blind study of two groups of 15 patients. The times to onset of sensory and motor block and to resolution of motor block, as well as the time to onset and degree of post-operative pain were recorded by an observer blinded to the identity of drug. Times to onset of sensory block were similar in the two groups (ropivacaine 10 min, mepivacaine 8 min). Resolution of motor block in the operated hand and the time to first requirement of post-operative analgesia occurred later with ropivacaine (9 h 50 min and 10 h) than with mepivacaine (3 h 50 min and 6 h), P < 0.01 for both measurements. Nine patients who received ropivacaine and two patients who received mepivacaine did not require further post-operative analgesia (P < 0.05). Ropivacaine is less toxic than other long-acting local anaesthetics, and 0.75% ropivacaine may be better for brachial plexus block when fast onset is required and prolonged pain relief is useful.

A double-blind comparison of ropivacaine, bupivacaine, and mepivacaine during sciatic and femoral nerve blockade.

UNLABELLED: No study has evaluated the efficacy of ropivacaine in peripheral nerve block of the lower extremity. The purpose of this prospective, randomized, double-blind study was to compare ropivacaine, bupivacaine, and mepivacaine during combined sciatic-femoral nerve block. Forty-five ASA physical status I or II patients scheduled for elective hallux valgus repair with thigh tourniquet were randomized to receive combined sciatic-femoral block with 0.75% ropivacaine (ROPI, n = 15), 0.5% bupivacaine (BUPI, n = 15), and 2% mepivacaine (MEPI, n = 15). Time required for onset of sensory and motor block on the operated limb (readiness for surgery) and resolution of motor block, as well as onset of postsurgical pain and time of first analgesic requirement, were recorded. The three groups were similar with regard to demographic variables, duration of surgery, and measured visual analog pain scores. Onset of sensory and motor blockade was similar in Groups ROPI and MEPI and significantly shorter than in Group BUPI (P = 0.002 and P = 0.001, respectively). Resolution of motor block occurred later in Groups ROPI and BUPI than in Group MEPI (P = 0.005 and P = 0.0001, respectively). Duration of postoperative analgesia was significantly longer in Groups ROPI (670+/-227 min) and BUPI (880+/-312 min) compared with Group MEPI (251+/-47 min) (P = 0.0001), with a significant decrease in postoperative pain medication requirements (P < 0.05). We conclude that for sciatic-femoral nerve block, 0.75% ropivacaine has an onset similar to that of 2% mepivacaine and a duration of postoperative analgesia between that of 0.5% bupivacaine and 2% mepivacaine. IMPLICATIONS: Quick onset of block with prolonged postoperative analgesia is an important goal in peripheral nerve blockade. We evaluated the clinical properties of 0.5% bupivacaine, 2% mepivacaine, and 0.75% ropivacaine for sciatic-femoral nerve block and demonstrated that ropivacaine has an onset similar to that of mepivacaine but allows for postoperative analgesia between that of bupivacaine and mepivacaine.

Effects of spinal needle type on lateral distribution of 0.5% hyperbaric bupivacaine.

UNLABELLED: To evaluate the influence of needle type on the lateral distribution of 0.5% hyperbaric bupivacaine, 30 patients undergoing lower limb surgery were placed in the lateral position with the side to be operated on dependent and underwent dural puncture by either a 25-gauge Whitacre (n = 15) or a 25-gauge Quincke (n = 15) spinal needle. The needle hole was turned toward the dependent side and 8 mg of 0.5% hyperbaric bupivacaine was injected over 30 s. The lateral position was maintained for 15 min while a blind observer recorded loss of pinprick sensation and degree of motor block on both the dependent and nondependent sides every 5 min until regression of motor block by 1 degree on the dependent side. Thirty minutes after the patients were placed in the supine position, unilateral sensory block was observed in 10 patients in the Whitacre group (66%) and in 2 patients in the Quincke group (13%) (P < 0.05). No differences in the rate of unilateral motor block were observed (73% and 40% in Whitacre and Quincke groups, respectively). We conclude that when a small dose of 0.5% hyperbaric bupivacaine is injected slowly into patients in the lateral position for 15 min, the Whitacre spinal needle provides a more marked differential block of sensory nerve roots between dependent and nondependent sides compared with the Quincke needle. IMPLICATIONS: Because unilateral spinal anesthesia can be advantageous for lower limb surgery, we evaluated the influence of the Whitacre and Quincke spinal needle types on the lateral distribution of small-dose 0.5% hyperbaric bupivacaine injected slowly into adult patients.