A randomised controlled trial comparing two popliteal nerve catheter tip positions for postoperative analgesia after day-case hallux valgus repair.

We compared the effect of two different positions of a sciatic nerve catheter within the popliteal fossa on local anaesthetic consumption and postoperative analgesia in patients undergoing day-case hallux valgus repair. Eighty-four patients were randomly allocated to receive a sciatic nerve catheter either between the tibial and peroneal components (sciatic group) or medial to the tibial nerve (tibial group). The primary endpoint was postoperative local anaesthetic consumption, while secondary endpoints were pain scores, number of occasions where sleep was disturbed by pain and incidence of insensate limb and foot drop at 24 h and 48 h postoperatively. Postoperative median (IQR [range]) local anaesthetic consumption was 126 (106-146 [98-180]) ml in the sciatic group versus 125 (114-158 [98-200]) ml in the tibial group (p = 0.103). Insensate limb occurred in 14 patients in the sciatic group versus one patient in the tibial group (p < 0.001), while foot drop was reported by six patients in the sciatic group and none in the tibial group (p = 0.012). Sciatic nerve catheter placement medial to the tibial nerve may be a superior analgesic technique for day-case foot surgery.

A randomised controlled trial of intrathecal blockade versus peripheral nerve blockade for day-case knee arthroscopy.

We allocated 100 patients scheduled for day-case knee arthroscopy to unilateral spinal anaesthesia with 40 mg intrathecal hyperbaric prilocaine or to ultrasound-guided femoral-sciatic nerve blockade with 25 ml mepivacaine 2%, 50 participants each. The median (IQR [range]) time to walk was 285 (240-330 [160-515]) min after intrathecal anaesthesia vs 328 (280-362 [150-435]) min after peripheral nerve blockade, p = 0.007. The median (IQR [range]) time to home discharge was 310 (260-350 [160-520]) min after intrathecal anaesthesia vs 335 (290-395 [190-440]) min after peripheral nerve blockade, p = 0.016. There was no difference in time from anaesthetic preparation to readiness for surgery.

A randomised controlled comparison between stimulating and standard catheters for lumbar plexus block.

The aim of this randomised, prospective, blinded study was to evaluate if stimulating catheters can decrease the minimum effective anaesthetic volume in 50% of patients during lumbar plexus block using mepivacaine 1.5% compared with standard catheters. Fifty-eight patients of ASA physical status 1-3 were randomly allocated to receive a lumbar plexus block via a stimulating or standard catheter, with 29 in each group. The first dose was 30 ml and subsequent doses were determined using the up-and-down staircase method. The minimum effective anaesthetic volume50 was 12.2 ml (95% CI 7.3-17.1 ml) using the stimulating catheter and 24.8 ml (95% CI 23.2-27.5 ml) with the standard catheter (p < 0.0001). Complete lumbar plexus block was achieved with the initial dose of mepivacaine in 29 (100%) patients in the stimulating catheter group and 20 (69%) patients in the standard catheter group (p = 0.002). This study showed that use of a stimulating catheter halves the minimum effective anaesthetic volume50 of mepivacaine 1.5% while increasing the success rate in patients receiving continuous lumbar plexus block.

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.

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.

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.

Randomized comparison of remifentanil-propofol with a sciatic-femoral nerve block for out-patient knee arthroscopy.

BACKGROUND AND OBJECTIVE: To evaluate preparation and discharge times as well as the anaesthesia-related costs of out-patient knee arthroscopy performed with a combined sciatic-femoral nerve block, or a propofol-remifentanil general anaesthetic. METHODS: With Ethics Committee approval and written informed consent, 40 healthy patients were pre-medicated with intravenous midazolam (0.05 mg kg(-1)) and ketoprofen (50 mg). They were then randomly allocated to receive either a combined sciatic-femoral nerve block with 25 mL mepivacaine 2% (15 mL for the femoral nerve, 10 mL for the sciatic nerve) (PNB group, n = 20), or a general anaesthetic with a continuous intravenous infusion of remifentanil (0.1-0.3 microgkg(-1) min(-1)) and propofol (target plasma concentration 2-4 microg mL(-1)) with a laryngeal mask airway (GA group, n = 20). RESULTS: The median (range) preparation time was 16 (10-28)min in the PNB group and 13 (8-22)min in the GA group (P = 0.015). Ten PNB patients were directly discharged to the day-surgery unit after the procedure as compared with one GA patient (P = 0.003). Discharge from the postanaesthesia care unit (PACU) required 5 (5-20) min in the PNB group and 23 (7-95) min in the GA group (P = 0.001). Home discharge criteria were fulfilled after 277 (150-485) min in the PNB group and 170 (100-400) min in the GA group (P = 0.005). Costs related to the time spent in the PACU were lower for the PNB group (1.10 euro, range Euro 0-22 euro) compared with the GA group (30 euro, range 0-176 euro) (P = 0.0005). There were no differences in total costs: PNB group 158 euro (range 105-194 euro) versus GA group 160 euro (range 101-238 euro) (P = 0.61). CONCLUSIONS: In patients undergoing out-patient knee arthroscopy, the length of stay in the PACU can be shorter after a sciatic-femoral nerve block with a small volume of mepivacaine 2% compared with a propofol-remifentanil anaesthetic, and there is an increased likelihood that they will bypass the first phase of the postoperative recovery.

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.

Interscalene brachial plexus anaesthesia with small volumes of ropivacaine 0.75%: effects of the injection technique on the onset time of nerve blockade.

BACKGROUND AND AIM: We evaluated the effect of the injection technique on the onset time and efficacy of interscalene brachial plexus anaesthesia. METHODS: With Ethical Committee approval and written consent, 30 patients undergoing elective shoulder acromioplasty or capsuloplasty were randomly allocated to receive interscalene brachial plexus block with 20 mL of ropivacaine 0.75% by using either a single injection (Single group, n = 15) or multiple injection (Multiple group, n = 15). Nerve blocks were placed with the aid of a nerve stimulator using short bevelled, Teflon coated needles. The stimulation frequency was set at 2 Hz and the intensity of stimulating current, initially set at 1 mA, was gradually decreased to < or = 0.5 mA after each muscular twitch was observed. In the Single group, the anaesthetic solution was slowly injected after the first muscular twitch had been observed. In the Multiple group, 8 mL were injected at shoulder abduction, 6 mL were injected at arm flexion, and 6 mL at the extension of the arm. RESULTS: Placing the block required 5 min (4-8 min) in the Multiple group and 3 min (1-10 min) in the Single group (P = 0.001); however, total preoperative time (from skin disinfection to complete loss of pinprick sensation from C4 to C7 with inability to elevate the limb from the operating table) was shorter in the Multiple group (15 min; range 10-28 min) than in the Single group (23 min; range 14-60 min) (P = 0.03). Additional intravenous fentanyl supplementation was required in two patients of the Multiple group (13%) and eight patients of the Single group (53%) (P = 0.05). CONCLUSION: We conclude that using a multiple injection technique shortened the preparation time and improved the quality of interscalene brachial plexus anaesthesia performed with small volumes of ropivacaine 0.75%.

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.

Unilateral spinal anesthesia or combined sciatic-femoral nerve block for day-case knee arthroscopy. A prospective, randomized comparison.

BACKGROUND: To evaluate the time required to achieve surgical block and fulfill standardized discharge criteria in outpatients receiving knee arthroscopy with either unilateral spinal anesthesia or combined sciatic-femoral nerve block. METHODS: After a standard midazolam/ketoprofen premedication and baseline measurement of cardiovascular parameters, 50 ASA physical status I-II patients scheduled for elective outpatient knee arthroscopy were randomized to receive unilateral spinal anesthesia with 8 mg of 0.5% hyperbaric bupivacaine injected without barbotage through a 25-gauge Whitacre spinal needle (group USA, n = 25), or combined sciatic-femoral nerve block with 25 ml of 2% mepivacaine (15 ml for femoral nerve block and 10 ml for sciatic nerve block) (group SFNB, n = 25). Times from local anesthetic injection to achievement of surgical block defined as the presence of adequate motor (complete motor blockade of the operated limb in the USA group and inability to move the ankle and the knee of the operated limb in the SFNB group) and sensory (loss of pinprick sensation at T12 on the operated side in the USA group, or in the femoral and sciatic nerves distribution in the SFNB group) blocks was recorded. Times to block resolution, urination, unassisted ambulation, and readiness to home discharge were also recorded by a blind observer, as well as occurrence of untoward events during surgery. RESULTS: Surgical block was achieved in 15 +/- 6 min in group USA and 16 +/- 6 min in group SFNB (p = NS). No differences in hemodynamic undesired effects and success rate were observed. Even though USA patients showed a faster time to ambulation (166 +/- 44 min versus 217 +/- 49 min, p = 0.002) and later urination (240 +/- 90 min versus 145 +/- 36 min, p = 0.0001) than SFNB group, no differences in home discharging were reported (246 +/- 98 min versus 211 +/- 77 min, respectively). Bladder catheterization was required in 2 patients of USA group only; however, no patient was admitted to the hospital because of urinary retention. CONCLUSIONS: In outpatient knee arthroscopy, a combined sciatic-femoral nerve block with 2% mepivacaine provides similarly successful anesthesia with onset times and home discharge similar to those provided by unilateral spinal anesthesia.

Regional anaesthesia for outpatient knee arthroscopy: a randomized clinical comparison of two different anaesthetic techniques.

BACKGROUND: The purpose of this prospective, randomized study was to evaluate the time required to perform anaesthesia, achieve surgical block and fulfil standardized discharge criteria in outpatients receiving knee arthroscopy with either spinal anaesthesia or combined sciatic-femoral nerve block. METHODS: After a standard midazolam/ketoprofen premedication and baseline measurement of cardiovascular parameters, 50 ASA I-II patients scheduled for elective outpatient knee arthroscopy were randomized to receive spinal anaesthesia with 8 mg of 0.5% hyperbaric bupivacaine (group Spinal, n=25), or combined sciatic-femoral nerve block with 25 ml of mepivacaine 20 mg ml(-1) and a multiple injection technique (15 ml for femoral nerve block and 10 ml for sciatic nerve block). Times lasting from skin disinfection to the end of local anaesthetic injection (preparation time) and then to achieve surgical anaesthesia (readiness for surgery), as well as times required for block resolution, micturition, unassisted ambulation, and home discharge were recorded by a blinded observer. Occurrence of adverse events was also recorded. RESULTS: Preparation time (mean+/-SD) was longer with sciatic-femoral block (8+/-2.7 min) than spinal anaesthesia (5+/-2.1 min) (P=0.0002) while no differences were observed in the time required to achieve readiness for surgery (14+/-5 min and 15+/-6 min in the Spinal and Sciatic-femoral groups, respectively). No differences in haemodynamic side effects and need for intraoperative additional analgesia were observed. Patients receiving spinal anaesthesia showed a faster resolution of nerve block and longer time to micturition (137+/-49 min and 231+/-101 min) than patients receiving peripheral nerve blockade (206+/-51 min and 145+/-36 min) (P<0.0005 and P=0.002, respectively); however, no differences were observed in the time required to fulfil standardized discharge criteria (241+/-101 min in group Spinal and 209+/-70 min in group Sciatic-femoral; P=0.86). CONCLUSION: In patients receiving elective outpatient knee arthroscopy, using a combined sciatic-femoral nerve block with 25 ml of mepivacaine 20 mg ml(-1) and a multiple injection technique results in a slightly longer preoperative time but provides similarly effective anaesthesia with no differences in home discharge times as compared to spinal anaesthesia with 8 mg hyperbaric bupivacaine.

The pressor response after laryngeal mask or cuffed oropharyngeal airway insertion.

BACKGROUND: Since the cuffed oropharyngeal airway (COPA) has been suggested to cause less pharyngeal trauma than the laryngeal mask airway (LMA), we conducted a prospective, randomised study to compare haemodynamic changes after placing either the COPA or LMA in healthy anaesthetised adults. METHODS: After standard midazolam premedication (0.05 mg kg(-1) IV), general anaesthesia (IV propofol 2 mg kg(-1)) was induced in 60 ASA physical status I-II, 18-65-yr-old patients, who were randomly allocated to receive COPA (n=30) or LMA (n= 30) placement and then mechanically ventilated using a 60% nitrous oxide and 1% isoflurane in oxygen mixture (TV=8 ml kg(-1), RR=12 b.p.m., I/E=1/2). Haemodynamic variables were recorded 20 min after the midazolam premedication (baseline), and then every 1 min until 10 min after general anaesthesia induction. RESULTS: Nine patients of group COPA (30%) required chin lift, jaw thrust or head tilt to maintain adequate ventilation, while no problems were observed in the LMA group (P<0.0005); however, in no case did the designed extratracheal airway have to be removed due to unsuccessful mechanical ventilation, and no signs of gastric insufflation or regurgitation were reported. The maximum mean changes in haemodynamic variables were more marked after LMA placement (SAP: 12%+/-13%; DAP: 11%+/-18%; HR: 13%+/-16%) than COPA placement (SAP: -3%+/-18%; DAP: -5%+/-16%; HR: 4%+/-13%) (P<0.005, P<0.005, and P<0.01 for SAP, DAP and HR, respectively). Group LMA showed higher SAP and DAP values than group COPA only during the first 3 min after airway insertion. CONCLUSION: In healthy, anaesthetised patients, placing a cuffed oropharyngeal airway is associated with smaller cardiovascular changes after airway insertion compared with the laryngeal mask airway.

Arterial to end-tidal carbon dioxide tension difference in anaesthetized adults mechanically ventilated via a laryngeal mask or a cuffed oropharyngeal airway.

To evaluate arterial (PaCO2), end-tidal (PETCO2) and carbon dioxide tension difference during mechanical ventilation with extratracheal airways, 60 patients ASA physical status I-II, receiving general anaesthesia for minor extra-abdominal procedures were randomly allocated to receive either a cuffed oropharyngeal airway (group COPA, n = 30) or a laryngeal mask (group LMA, n = 30). The lungs were mechanically ventilated by IPPV using a 60% nitrous oxide and 1-1.5% isoflurane in oxygen mixture (VT = 8 mL kg-1; RR = 12 b min-1; l/E = 1/2). After PETCO2 had been stable for at least 10 min after airway placement, haemodynamic variables and PETCO2 were recorded and an arterial blood sample was obtained for measurement of PaCO2. No differences in anthropometric parameters, smoking habit, haemodynamic variables and incidence of untoward events were observed between the two groups. Airway manipulation, to maintain adequate ventilation, was required in only nine patients in the cuffed oropharyngeal airway group (30%) (P < 0.0005); however, in no case was it necessary to remove the designated extratracheal airway due to unsuccessful mechanical ventilation. The mean difference between arterial and end-tidal carbon dioxide partial pressure was 0.4 +/- 0.3 KPa in the laryngeal mask group (95% confidence intervals: 0.3-0.5 KPa) and 0.3 +/- 0.26 KPa in the cuffed oropharyngeal airway group (95% confidence intervals: 0.24-0.4 KPa) (P = NS). We conclude that in healthy adults who are mechanically ventilated via the cuffed oropharyngeal airway, the end-tidal carbon dioxide determination is as accurate an indicator of PaCO2 as that measured via the laryngeal mask, allowing capnometry to be reliably used to evaluate the adequacy of ventilation.

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.

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.