Search

Background and Objectives: Unilateral spinal anesthesia may be obtained with hypobaric or hyperbaric solution. The objective of this study was to compare different doses of enantiomeric excess hyperbaric levobupivacaine to achieve unilateral spinal anesthesia., Method: One hundred and twenty patients were randomized to receive 4 mg, 6 mg or 8 mg of 0.4% enantiomeric excess levobupivacaine. The solutions were administered at the L3-L4, with the patient in a lateral position and kept at this position according to dose administration for 5, 10 or 15 minutes. Sensory block (pinprick) and motor block (scale 0-3) were compared between the operated and contralateral sides., Results: The onset of analgesia was rapid and comparable between groups. Sensory block was significantly higher in the operated than in nonoperated limb at all times of evaluation. Increasing the dose by 1 mL (2mg) corresponded to an increase of two segments in the mode for the operated side. In the operated side, motor block (MB = 3) of patients occurred in 31 (77.5%) with 4 mg, 38 (95%) with 6 mg, and 40 (100%) with 8 mg. There was a positive correlation between increased dose, blockade duration, and hypotension. All patients were satisfied with the technique used., Conclusions: Spinal anesthesia with different volumes of enantiomeric excess hyperbaric bupivacaine (S75: R25) provided a 78% incidence of unilateral spinal block, with the smallest dose used (4 mg) the most efficient., (Copyright © 2012 Elsevier Editora Ltda. All rights reserved.)

Background and Objectives: Low doses of bupivacaine and lidocaine have been used for spinal anesthesia in outpatient surgery. The objective of this study was to compare hypobaric solutions of bupivacaine and lidocaine in outpatient anorectal surgery., Methods: One hundred and fifty patients, divided in two groups, physical status ASA I-II, scheduled for anorectal surgery in the jackknife position received 3 mL (4.5 mg) of hypobaric 0.15% bupivacaine or 3 mL (18 mg) of hypobaric 0.6% lidocaine. The selectivity of the blockade, quality of surgical anesthesia, intensity of the motor blockade, and time for patient recovery were compared. After patients were discharged, daily phone contact was maintained for three days and on the 30th postoperative day., Results: Adequate surgical blockade was achieved in all patients. The mean level of cephalad dispersion was L(1), ranging from T(10)-L(3), with bupivacaine, and L(1), ranging from T(11)-L(2), with lidocaine. Motor blockade was not observed in 135 patients (65 in the bupivacaine group x 70 in the lidocaine group). None of the patients developed hypotension and bradycardia. The sensorial blockade had a mean duration of 99.1 (11.0) minutes, with bupivacaine, and 64.1 (7.6) minutes, with lidocaine (p < 0.0005). Post-lumbar puncture headache was not observed in any patient., Conclusions: Hypobaric solution of bupivacaine or lidocaine promotes, predominantly, sensorial blockade after subarachnoid injection in patients in the jackknife position. Hypobaric lidocaine provides analgesia with the same dispersion of that of bupivacaine, but with shorter duration. Hemodynamic stability and the absence of motor blockade represent the major advantages.

Background and Objectives: The relative density of a local anesthetic in relation to that of the cerebrospinal fluid (CSF) at 37 degrees C is one of the most important physical properties that affect the level of analgesia obtained after the subarachnoid administration of the drug. The objective of this study was to determine the density of local anesthetic solutions, with and without glucose, and the combination of the local anesthetic with adjuvants at 20 degrees C, 25 degrees C, and 37 degrees C., Methods: The density (g.mL(-1)) was determined by using a DMA 450 densimeter with a sensitivity of +/- 0.00001 g.mL(-1). The densities, and variations, according to the temperature were obtained for all local anesthetics and their combination with opioids at 20 degrees C, 25 degrees C, and 37 degrees C. The solution is hyperbaric if its density exceeds 1.00099, hypobaric when its density is lower than 1.00019, and isobaric when its density is greater than 1.00019 and lower than 1.00099., Results: The densities of both local anesthetics and adjuvants decrease with the increase in temperature. At 37 degrees C, all glucose-containing solutions are hyperbaric. In the absence of glucose, all solutions are hypobaric. At 37 degrees C, morphine, fentanyl, sufentanil, and clonidine are hypobaric., Conclusions: The densities of local anesthetics and adjuvants decrease with the increase in temperature and increase when glucose is added. The knowledge of the relative density helps select the most adequate local anesthetic to be administered in the subarachnoid space.

Background and Objectives: Unilateral spinal anesthesia has its advantages, especially in patients undergoing outpatient basis surgeries. Low dose, slow speed of administration, and the lateral positioning make easier the unilateral distribution in spinal anesthesia. Isobaric, hyperbaric, and hypobaric solutions of bupivacaine were compared in the unilateral spinal anesthesia in patients undergoing outpatient basis orthopedic surgeries., Methods: One hundred and fifty patients were randomly divided in three groups to receive 5 mg of 0.5% isobaric bupivacaine (Iso Group), 5 mg of 0.5% hyperbaric bupivacaine (Hyper Group), or 5 mg of 0.15% hypobaric bupivacaine (Hypo Group). The solutions were administered in the L3-L4 space with the patient in the lateral decubitus and remaining in this position for 20 minutes. Sensitive anesthesia was evaluated by the pin prick test. Motor blockade was determined by the modified Bromage scale. Both blockades were compared with the opposite side and among themselves., Results: There was a significant difference between the side of the surgery and the opposite side in all three groups at 20 minutes, but the frequency of unilateral spinal anesthesia was greater with the hyperbaric and hypobaric solutions. Sensitive and motor blockades were observed in 14 patients in the Iso Group, 38 patients in the Hyper Group, and 40 patients in the Hypo Group. Patients did not develop any hemodynamic changes. Postpuncture headache and transitory neurological symptoms were not observed., Conclusions: Spinal anesthesia with hypobaric and hyperbaric solutions present a higher frequency of unilateral anesthesia. After 20 minutes, isobaric bupivacaine mobilized into cerebrospinal fluid (CSF) resulted in unilateral spinal anesthesia in only 28% of the patients.

Background and Objectives: The aim of this study was to study low dose hypobaric 0.15% bupivacaine and hyperbaric 0.5% bupivacaine in outpatient anorectal surgical procedures., Methods: Two groups of 50 patients, physical status ASA I and II, undergoing anorectal surgical procedures in a jackknife position, received 6 mg of hypobaric 0.15% bupivacaine in the surgical position (Group 1) or 6 mg of hyperbaric 0.5% bupivacaine in the sitting position for 5 minutes, after which they were placed in a jackknife position (Group 2). Sensitive and motor blockade, time of first urination, ambulation, complications, and the need for analgesics were evaluated. Patients were followed until the third postoperative day and questioned whether they experienced post-puncture headache or temporary neurological symptoms, and until the 30th day and questioned about permanent neurological complications. The test t Student, Mood's median, and Fisher Exact test were used for statistical analysis, and a p < 0.05 was considered significant., Results: Every patient in Group 1 presented selective blockade of the posterior sacral nerve roots, while patients in Group 2 experienced blockade of the anterior and posterior nerve roots. Blockade was significantly higher in Group 1. Motor blockade was significantly less severe in Group 1. Forty-nine patients in Group 1 transferred to the stretcher unassisted while only 40 patients in Group 2 were able to do so. Recovery in Group 1 occurred in 105 +/- 25 minutes and in 95 +/- 15 minutes in Group 2, and this difference was not statistically significant. There were no hemodynamic changes, nausea or vomiting, urine retention, or post-puncture headache., Conclusions: Anorectal surgical procedures under spinal block with low dose bupivacaine, hyperbaric or hypobaric, can be safely done.

Background and Objectives: The increasing number of ambulatory procedures requires anesthetic methods allowing patients to be discharged soon after surgery completion. Currently, anorectal procedures are performed in inpatient settings. This study aimed at evaluating the feasibility of performing these procedures in outpatient settings with low hypobaric bupivacaine doses., Methods: Participated in this study 30 patients physical status ASA I and II, submitted to spinal anesthesia with 0.15% hypobaric bupivacaine with 27G Quincke needle for anorectal procedures. Spinal puncture was performed with patients in the prone position with the help of a pad under the abdomen to correct lumbar lordosis and the vertebral interspace., Results: Sensory block was obtained in all patients. Sensory block spread varied T10 to L2 (mode = T12). Only three patients presented motor block. Blockade length was 122.17 +/- 15.35 minutes. No hemodynamic changes were observed in all patients. No patient developed post-dural puncture headache., Conclusions: Hypobaric bupivacaine (6 mg) has provided predominantly sensory block after injection in the prone position. Major advantages were hemodynamic stability and patients' satisfaction, being a good indication for outpatient anesthesia.

Background and Objectives: Unilateral spinal anesthesia may be advantageous, especially in the outpatient setting. Low local anesthetic doses, slow spinal injection rate and the lateral position have been related to the easiness of inducing unilateral spinal anesthesia. This study aimed at investigating the possibility of inducing unilateral spinal anesthesia with isobaric 0.5% bupivacaine., Methods: Spinal anesthesia with 1 mL isobaric 0.5% bupivacaine (5 mg) was induced through 27G Quincke needle in 25 physical status ASA I and II patients undergoing orthopedic procedures. Dural puncture was performed with patients in lateral decubitus with the limb to be operated facing upwards. One mililiter of isobaric bupivacaine was injected in 30 seconds. Sensory and motor blocks were compared between the operated and the contralateral side., Results: Motor and sensory blocks on operated and contralateral sides were significantly different in all studied moments. All patients presented surgical anesthesia in the operated limb. At 20 minutes, nine patients presented sensory block in the contralateral side; at 40 minutes they were 18 and at 60 minutes they were 17 patients. So, unilateral block was present in seven patients (28%) and bilateral block was present in the remaining 18 patients (72%). No patient developed post-dural puncture headache., Conclusions: Isobaric bupivacaine (5 mg) provides predominant unilateral block after 20 minutes in the lateral position. Isobaric bupivacaine moves in the CSF after 20 minutes resulting in just 28% unilateral blocks. Major advantages of unilateral spinal anesthesia are hemodynamic stability and short duration and it might be a new alternative for outpatient procedures.

Background and Objectives: The possibility to achieve unilateral spinal anesthesia with 0.15% bupivacaine was studied with the purpose of minimizing hemodynamic changes, limiting the cephalad dispersion of the anesthetic and promoting a faster recovery., Methods: Twenty ASA I - II patients undergoing orthopedic surgeries were given spinal 0.15% hypobaric bupivacaine through a 27G Quincke needle. Dural puncture was performed with patients in the lateral position, with the limb to be operated upwards, and 3.3 ml (5 mg) hypobaric bupivacaine were injected at the rate of 1 ml.15 s(-). Sensory and motor block (pinprick and 0 to 3 scale) were compared between operated and contralateral sides., Results: Motor and sensory block in operated and contralateral sides were significantly different in all evaluated times. Unilateral spinal anesthesia was achieved in 75% of patients. All patients remained hemodynamically stable, and no one developed post-dural puncture headache., Conclusions: Hypobaric bupivacaine (5 mg) is able to provide a predominant unilateral block with the patient being kept twenty minutes in the lateral position. Major unilateral spinal anesthesia advantage is hemodynamic stability.

Background and Objectives: Spinal block for cesarean section was described few years after the first report of spinal anesthesia by Bier in 1899. It was not until the last 5 years that spinal anesthesia has become the most frequent anesthetic method for cesarean section at our hospital. This prospective study aimed at evaluating 0.5% spinal isobaric bupivacaine for cesarean section, injected after fentanyl and morphine, in the lateral position, and at correlating the incidence of hemodynamic changes and cephalad spread with different volumes., Methods: Participated in this study 100 patients undergoing spinal anesthesia for elective cesarean delivery who were randomly allocated into three groups to receive: 4 ml (20 mg), 3 ml (15 mg) or 2.5 ml (12.5 mg) of 0.5% isobaric bupivacaine after 25 microg fentanyl plus 50 microg morphine. The following parameters were evaluated and compared: analgesia and motor block onset, cephalad spread of analgesia, cardiovascular changes and the incidence of nausea and vomiting., Results: The three volumes of 0.5% isobaric bupivacaine produced comparable effects. Onset was longer for the lowest dose. There were no differences in cephalad spread, number of patients with high cervical levels, cardiovascular changes and post dural puncture headache. Maximum analgesic level was T4 (range: T3-T6) with 4 ml, T4 (range: T4-T11) with 3 ml and T4 (range: T4-T8) with 2.5 ml. No patient required ephedrine to treat arterial hypotension. Motor block was incomplete for all patients. One patient developed post dural puncture headache., Conclusions: Results of this study confirm that 0.5% isobaric bupivacaine, following fentanyl and morphine injected with separate syringes and in the lateral position, in doses of 2.5, 3 and 4 ml provides a fast and effective anesthesia for cesarean section.

Background and Objectives: Restricted sympathetic block during spinal anesthesia may minimize hemodynamic changes. In theory, the use of non-isobaric local anesthetics may induce unilateral anesthesia and limit sympathetic blockade to one side of the body. The local anesthetic dose and the time patients need to remain in the lateral position for achieving unilateral spinal anesthesia are not known. This prospective study investigated the incidence of unilateral spinal anesthesia following injection through a 27G Quincke needle of 0.15% hypobaric bupivacaine, prepared with 1.5 ml standard isobaric bupivacaine plus fentanyl (25 microg), in patients in the lateral position with the limb to be operated upwards., Methods: Spinal anesthesia with 0.15% bupivacaine + fentanyl (25 microg) was induced through a 27G Quincke needle in 22 ASA I and II patients undergoing orthopedic surgery. Dural puncture was performed with the patient in the lateral position with the side to be operated upwards. After removal of 3 to 5 ml of CSF, 5 ml of the hypobaric bupivacaine-fentanyl mixture were injected at a speed of 1 ml.15 s-1. Sensory and motor block (pinprick/scale 0 to 3) were compared between operated and contralateral sides., Results: Motor and sensory blocks in operated and contralateral sides were significantly different in all moments for both groups. Unilateral spinal anesthesia was obtained in 71% of the patients. No hemodynamic changes were observed in any patient. No patient developed post-dural puncture headache., Conclusions: Hypobaric 0.15% bupivacaine (7.5 mg) associated to fentanyl provided a predominantly unilateral block after twenty minutes in the lateral position. Major advantages of unilateral spinal anesthesia were hemodynamic stability, patient satisfaction and the absence of post-dural puncture headache.