Anesthesia and analgesia
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Anesthesia and analgesia · Nov 1999
Randomized Controlled Trial Comparative Study Clinical TrialVisual estimation of onset time at the orbicularis oculi after five muscle relaxants: application to clinical monitoring of tracheal intubation.
The onset time of neuromuscular blockade at the adductor pollicis (AP) is different among neuromuscular blocking drugs, but these discrepancies had never been studied at the orbicularis oculi (OO). The purpose of this study was to verify if the differences in onset time observed at the AP still existed at the OO and to score the intubating conditions using monitoring at the OO after five muscle relaxants. The study included 172 adults aged 18-75 yr. Anesthesia was induced with fentanyl and propofol. Atracurium (0.5 mg/kg), mivacurium (0.20 mg/kg), rocuronium (0.6 mg/kg), succinylcholine (1.0 mg/kg), or vecuronium (0.08 mg/kg) was injected by random allocation. Time to complete disappearance of the response at the OO was assessed visually after train-of-four stimulation of the facial nerve. Laryngoscopy was then performed, and intubating conditions were determined on a scale of 1-4. Results were based on 150 patients. Onset time at the OO was (mean +/- SD): succinylcholine (57 +/- 17 s) < mivacurium (99 +/-19 s) = rocuronium (99 +/- 47 s) < atracurium (129 +/-33 s) = vecuronium (135 +/- 38 s) (P < 0.05). Overall intubating conditions were excellent (84%), good (14%), poor (1.3%), impossible (0.7%), and were similar among the five groups. We conclude that differences in onset time of muscle relaxants observed at the AP were also found at the OO. Visual estimation of the response at the OO correctly predicted good-to-excellent intubating conditions in more than 90% of cases for all the currently available muscle relaxants. ⋯ Onset time of neuromuscular blockade, as estimated visually at the orbicularis oculi, depends on the muscle relaxants given. Regardless of the relaxant used, intubating conditions at loss of orbicularis oculi are acceptable.
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Anesthesia and analgesia · Nov 1999
Randomized Controlled Trial Clinical TrialThe lateral approach to the sciatic nerve at the popliteal fossa: one or two injections?
It has not been proven whether one or multiple nerve stimulations and injections provide a higher rate of complete sensory block in both major sciatic nerve sensory distributions below the knee when a popliteal sciatic nerve block is performed using the lateral approach. This prospective, randomized, single-blinded study compared the success rate of the sciatic nerve block using this approach when one or both major components of this nerve (i.e., tibial nerve and common peroneal nerves) are stimulated in 50 patients undergoing foot or ankle surgery. In Group 1 STIM, 24 patients received a single injection of 20 mL of a mixture of 2% lidocaine and 0.5% bupivacaine with 1:200,000 epinephrine after foot inversion had been elicited. In Group 2 STIM (n = 26), 10 mL of the same solution was injected after stimulation of each sciatic nerve component. For patients with complete sensory motor block, there was no difference in onset between groups. However, Group 2 STIM showed a greater success rate compared with the Group 1 STIM (2 STIM: 88% vs 1 STIM :54%; P = 0.007). When two stimulations were used, the onset time of anesthesia in the cutaneous distribution of the common peroneal nerves was shorter than in the tibial nerve (17.5 vs 30 min; P < 0.0001). We conclude that a two-stimulation technique provides a better success rate than a single-injection technique when a popliteal sciatic nerve block is performed using the lateral approach with 20 mL of local anesthetic. ⋯ A better success rate is achieved with a double stimulation technique than with a single injection for the sciatic nerve block via the lateral approach at the popliteal fossa when 20 mL of local anesthetics is used.
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Anesthesia and analgesia · Nov 1999
Randomized Controlled Trial Clinical TrialTeaching the use of fiberoptic intubation in anesthetized, spontaneously breathing patients.
In patients with difficult airways, the standard of care involves fiberoptic intubation under spontaneous ventilation. However, the safety and feasibility of a fiberoptic intubation teaching program has only been documented in paralyzed and apneic patients, whereas data obtained in patients under spontaneous respiration are limited and conflicting. We evaluated 100 anesthetized patients undergoing orotracheal fiberoptic intubation. Five anesthesia residents with no prior experience in fiberoptic laryngoscopy participated in the study. In a randomized fashion, each participant tracheally intubated 10 spontaneously breathing patients (Group A: sevoflurane anesthesia via an airway endoscopy mask) and 10 paralyzed patients (Group B: total IV anesthesia with propofol, fentanyl, atracurium). Overall rate of success (96%), defined as successful intubation of the trachea within two attempts, was not different between groups. During fiberoptic intubation, Spo2 values remained >95% in Group A, whereas Spo2 decreased to <95% in two patients in Group B. Failure to pass the tube into the trachea over the bronchoscope was encountered in four patients in Group A and in no patient in Group B. Our data suggest that it is safe to teach the use of fiberoptic intubation in anesthetized, spontaneously breathing patients with normal airway anatomy. ⋯ Fiberoptic intubation under spontaneous respiration is a well established technique for management of difficult airways. Our study demonstrates the feasibility and safety of a novice training program for fiberoptic intubation under general anesthesia, not only in paralyzed patients but also in those breathing spontaneously.
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Anesthesia and analgesia · Nov 1999
Randomized Controlled Trial Comparative Study Clinical TrialLidocaine plus ropivacaine versus lidocaine plus bupivacaine for peribulbar anesthesia by single medical injection.
This study was designed to compare the effects of ropivacaine and bupivacaine, each combined with lidocaine, during peribulbar anesthesia by single medial injection for cataract surgery. One hundred patients were included and randomly divided into two groups of 50, given a mixture of 50% bupivacaine (0.5%) and 50% lidocaine (2%) or 50% ropivacaine (1%) and 50% lidocaine (2%), and 25 U hyaluronidase per mL with each combination. After the first injection, patients given ropivacaine exhibited significantly better akinesia than those given bupivacaine, and significantly fewer were reinjected (19/50 vs 31/50). Among the patients reinjected, peroperative akinesia and analgesia proved satisfactory in both groups. We observed three cases of diplopia caused by retraction of the internal rectus muscle and two cases of moderate ptosis after superonasal reinjection. Hemodynamic profiles were similar in the two groups, and no major side effects were noted during the observation. One percent ropivacaine may be a more appropriate agent than 0.5% bupivacaine for peribulbar anesthesia by single medial injection. ⋯ One percent ropivacaine may be a more appropriate agent than 0.5% bupivacaine for peribulbar anesthesia by single medial injection. Combined with lidocaine, it provides better akinesia and similar analgesia.
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Anesthesia and analgesia · Nov 1999
Randomized Controlled Trial Clinical TrialModified continuous femoral three-in-one block for postoperative pain after total knee arthroplasty.
We prospectively studied the continuous "modified" femoral three-in-one block for postoperative pain after total knee arthroplasty. Sixty-two patients undergoing elective knee arthroplasty under spinal anesthesia with bupivacaine (B) and fentanyl were randomized to receive 0.2% B, 0.1% B, or placebo at 10 mL/h for 48 h after an initial bolus of 30 mL of the same solution via the femoral block catheter. The catheters were inserted under the fascia iliaca using a "double pop" technique and a peripheral nerve stimulator and were advanced 15-20 cm cranially. Venous plasma levels of B, desbutylbupivacaine, and 4-hydroxy B were measured daily for 3 days. All patients received patient-controlled analgesia with morphine and indomethacin suppositories for 48 h. Using computed tomography, we evaluated the catheter location for 20 patients. The catheter tips, located superior to the upper third of the sacroiliac joint in the psoas sheath, were labeled as ideally located. The group receiving 0.2% B had a larger block success rate, smaller morphine consumption in the immediate postoperative period (15 vs 22 mg) and during the first postoperative day (9 vs 18 mg), and achieved a greater range of motion in the immediate postoperative period (91 degrees +/- 10 degrees vs 80 degrees + 13 degrees ). Visual analog scores for pain during both rest and activity were low but similar between the groups. Forty percent of the catheters evaluated were ideally located. Ideal location and use of 0.2% B resulted in 100% success of blockade of all three nerves. The S1 root was blocked in up to 76% of patients. The plasma levels of B, 4-hydroxy B, and desbutylbupivacaine were below the toxic range during the infusion. We conclude that continuous fascia iliaca block with 0.2% B results in opioid-sparing and improved range of motion during the immediate postoperative period. Larger doses of bupivacaine may safely be used in the immediate postoperative period if needed. ⋯ Continuous fascia iliaca block with 0.2% bupivacaine reduces opioid requirements and improves range of motion in the immediate postoperative period compared with a placebo and 0.1% bupivacaine. Plasma levels are below the toxic range with this dose. Only 40% of the catheters are positioned in the ideal location. With the smaller dose of bupivacaine, the success rate with this block is small.