Alkalinization of lidocaine does not hasten the onset of axillary brachial plexus block

We assessed the onset of sensory and motor blockade as well as the distribution of sensory blockade after axillary brachial plexus block with 1.5% lidocaine hydrochloride 1:200,000 epinephrine with and without sodium bicarbonate in 38 patients. The onset of analgesia and anesthesia was recorded over the distributions of the median, ulnar, radial, and medial cutaneous nerves of the forearm, medial cutaneous and lateral cutaneous nerves of the arm, and musculocutaneous nerve. The onset of motor blockade of elbow and wrist movements was also recorded. Data were analyzed by using survival techniques and compared by using log rank tests. Only the onset of analgesia in the medial cutaneous nerves of the arm and forearm, and the onset of anesthesia in the medial cutaneous nerve of the arm were significantly faster (P < 0.05) with alkalinization of lidocaine. Our study showed that alkalinization of lidocaine does not significantly hasten block onset in most terminal nerve distributions. IMPLICATIONS: We examined whether alkalinizing a local anesthetic would quicken the onset of a regional upper limb nerve blockade. We found that alkalinization of lidocaine did not offer a significant clinical advantage in axillary brachial plexus blockade.     

Arm adduction does not increase block extension in anesthesia of the brachial plexus by the axillary approach

INTRODUCTION: Arm abduction of 90 degrees during injection of local anesthetic followed by adduction of the arm has been recommended traditionally to favor proximal distribution of local anesthetic and extension of the blockade in the brachial plexus by the axillary route. A recent study demonstrated that there are no clinical or radiological differences between axillary blockades performed with abduction or adduction. OBJECTIVE: To compare the extension of sensory blockade in axillary anesthesia performed with adduction or abduction. MATERIAL AND METHODS: Forty patients were randomly distributed in two groups, 20 in the adduction group and 20 in the abduction group. The axillary catheter was inserted 3 cm in the proximal direction and a mixture of 40 ml of 1.5% mepivacaine without adrenaline and 4 ml of 8.4% bicarbonate soda was injected into each patient. RESULTS: No statistically significant differences in extension of sensory blockade, including circumflex, musculocutaneous and radial nerve blockade, were observed. CONCLUSIONS: Axillary rotation of the arm is not a determining factor in sensory blockade in brachial plexus anesthesia by the axillary route.     

Critical and heretical thoughts on the development of cardiology. Limits of mental and social compliance attitude of the population

100 patients with ASA risk I & II and undergoing perianal surgery were studied for anaesthetic effects and postoperative analgesia following either intrathecal pethidine or lignocaine. Saddle block was performed either with intrathecal pethidine 5% (50 mg/ml) 0.5 mg/kg or 1 ml of 5% lignocaine. Sensory and motor block postoperative analgesia, need for additional analgesia were studied. The onset of sensory and motor blockade with lignocaine was faster than pethidine. However the sensory and motor blockade lasted longer with pethidine. The duration of postoperative analgesia was 15.39 +/- 5.14 hours as against duration of postoperative analgesia with lignocaine which was 1.3 +/- 0.53 hours. Only 10% of patients in the pethidine group required intramuscular analgesic supplementation whereas 30% of patients in the lignocaine group required intramuscular analgesic supplementation.     

Analgesia using continuous axillary block after surgery of severe hand injuries: self-administration versus continuous injection

OBJECTIVE: To compare analgesia produced after surgery for severe hand trauma, by a continuous axillary block obtained either with a continuous injection (CA) or controlled by the patient (PCA). STUDY DESIGN: Prospective, randomized study. PATIENTS: Forty-two ASA physical class 1 and 2 patients were enrolled over a twelve-month period and randomly allocated either into the CA or the PCA group. METHODS: After recovery from the surgical block, the axillary plexus was located using a nerve stimulator and a 20 G catheter (Contiplex B Braun) inserted over 5 centimeters into the axillary sheath. In the CA group (n = 21) patients received 0.1 mL.kg-1.h-1 of 0.25% bupivacaine and in the PCA group (n = 21) patients received 0.1 mL.kg-1 boluses of 0.25% bupivacaine with a one hour lock-out period. Data collected were pain intensity rated according to he visual analog scale (VAS), the total volume of bupivacaine injected, the quantity of nalbuphine administered as 10 mg boluses when VAS was = 5, and the patient's satisfaction after removal of the catheter. Statistical analysis used Student t test, ANOVA and chi 2 test. RESULTS: The mean duration of catheter use was 5 +/- 3 days. During this period the amount of bupivacaine was significantly reduced in the PCA group when compared to the CA group (P < 0.001). Similarly, the PCA group required significantly less nalbuphine. Finally, in this group, the satisfaction index was higher than in the CA group (95 versus 52% respectively, P < 0.01). CONCLUSION: Continuous axillary plexus blockade provides safe and effective postoperative analgesia. With the PCA technique results a lower quantity of bupivacaine is required and patient's satisfaction better.     

Caudal clonidine and bupivacaine for combined epidural and general anaesthesia in children

BACKGROUND: Clonidine produces analgesia by actions on alpha 2-adrenoceptors and enhances both sensory and motor blockade from epidural injection of local anaesthetics. Low-dose clonidine has been used so far for caudal injection in children. Our aim was to study the perioperative effects of high-dose caudal clonidine when added to low concentration of bupivacaine for combined epidural and general anaesthesia in children. METHODS: After induction of general anaesthesia caudal block was performed either with 1 ml.kg-1 bupivacaine 0.175% with the addition of clonidine 5 micrograms.kg-1 (n = 20), or with 1 ml.kg-1 bupivacaine 0.175% (n = 20). The intraoperative anaesthetic requirements, the perioperative haemodynamic effects, respiratory rate, sedation score, postoperative pain scores and side effects were assessed by a blinded observer. A patient-controlled analgesia system was used for postoperative pain relief. The quality of postoperative pain relief was assessed using Smiley's pain analogue scale. RESULTS: Intraoperative haemodynamic responses did not differ between the groups. However, during emergence from general anaesthesia children in the clonidine group had significantly lower heart rates and blood pressure compared to children in the control group. In addition, heart rates and blood pressures were also lower in the clonidine group in the early postoperative period (P < 0.05). Postoperative analgesia was significantly better in the clonidine group as evidenced by the total number of requests (3 vs 12, P < 0.05) and the total amount of tramadol (20.5 mg vs 72.8 mg, P < 0.05) administered. The duration of the caudal analgesia was significantly longer in the clonidine group (20.9 +/- 7.4 h vs 14.4 +/- 10.9 h, P < 0.05). CONCLUSION: Our results suggest that caudal clonidine 5 micrograms.kg-1 enhances and prolongs caudal blockade with bupivacaine (1.175% in children. It also blocks sympathoadrenergic responses during emergence from anaesthesia. Sedation and cardiovascular effects are observed up to 3 h into the postoperative period.     

Dose-response relationship of clonidine with epidural administration of ropivacaine in orthopedic procedures of the lower extremities

OBJECTIVE: The aim of this study was to investigate preliminarydose-range effects of clonidine added to ropivacaine for epidural analgesia in elective orthopedic surgery of the lower limbs with doses, causing a minimum of cardiovascular side effects. METHODS: 60 patients were randomly assigned to receive in a double-blind fashion a mixture of 1 mg/cm height ropivacaine plus saline or 1 mg/cm ropivacaine plus 25 micrograms, 50 micrograms, 75 micrograms, 100 micrograms or 150 micrograms clonidine for epidural analgesia. The sensory and motor function were determined at defined time intervals for 30 minutes. Heart rate and blood pressure were controlled and sedation score was judged. The postoperative 2-segment-regression of pin-prick and the onset of pain were recorded. RESULTS: The six groups were comparable in demographic data and in term of onset time. The prolongation of analgesia reached 513 +/- 92 min (p = 0.002) for 150 micrograms clonidine, 460 +/- 148 min (p = 0.073) for 100 micrograms clonidine, 440 +/- 86 min (p = 0.057) for 75 micrograms clonidine compared with 347 +/- 114 min for saline. In an equal manner, 2-segment-regression for pin-prick was extended to 251 +/- 47 min (p = 0.018) for 150 micrograms clonidine, 238 +/- 33 min (p = 0.034) for 100 micrograms clonidine, 229 +/- 29 min (p = 0.027) for 75 micrograms clonidine and 178 +/- 43 min for saline. Heart rate dropped down in all groups. Mean arterial pressure decreased significantly in the groups with 75, 100 and 150 micrograms clonidine. Sedation score increased continuously from 0.6 +/- 0.5 (saline) to 1.8 +/- 0.8 (150 micrograms clonidine). CONCLUSION: We conclude that 150 micrograms clonidine significantly enhances the duration of analgesia of epidurally administered ropivacaine in a mean of 171 mg. This time interval is longer than the one with 200 mg ropivacaine alone. But, there are side effects in form of decrease of arterial pressure. Cardiovascular monitoring seems to be essential. Because of the enhanced analgesia duration, the time interval for reloading epidural anaesthesia are increased.     

Limited-sampling strategy models for itraconazole and hydroxy-itraconazole based on data from a bioequivalence study

We assessed the sedative potential of continuous infusions of remifentanil with a validated composite alertness scale in 160 patients (ASA physical status I or II) undergoing hip replacement surgery with spinal block (n = 61) or hand surgery using brachial plexus block (n = 93). They were randomized to receive one of the following initial dose regimens in double-blinded fashion: placebo or 0.04, 0.07, or 0.1 microg x kg(-1) x min(-1) remifentanil subsequently titrated to effect. Additional midazolam IV was allowed for adequate sedation as required. The combined analysis of both surgery groups revealed a dose-related increase in achievement of sedation level > or =2 within 15 min of the start of the study drug infusion; all remifentanil dose comparisons with placebo reached significance (P < 0.001). The remifentanil 50% effective dose for a composite sedation level > or =2 within 15 min of the start of drug infusion was estimated as 0.043 microg x kg(-1) x min(-1) (95% confidence interval 0.01, 0.059). The requirement for midazolam decreased with increasing remifentanil dose compared with placebo (P < 0.001). The median time to return to alertness after the end of infusion was 10-12 min in the remifentanil groups and 5 min in the placebo group. Significant incidences of nausea, pruritus, sweating, and respiratory depression were reported during remifentanil infusions compared with placebo. The data suggest that remifentanil may be useful for supplementation of regional anesthesia, provided that ventilation is carefully monitored. IMPLICATIONS: In this dose-finding, placebo-controlled study, remifentanil infusions were used to provide sedation during spinal and brachial plexus regional anesthesia. The 50% effective dose for achievement of sedation was 0.043 microg x kg(-1) x min(-1). Return to alertness occurred after 10-12 min (median time). Remifentanil infusions can be used to supplement regional anesthesia, but this requires careful monitoring of ventilation.     

Continuous analgesia with a femoral catheter: plexus or femoral block?

OBJECTIVE: To evaluate the spread and quality of sensitive blockade produced by continuous and prolonged use of a femoral catheter inserted for postoperative analgesia. STUDY DESIGN: Prospective non comparative evaluation. PATIENTS: The study included 20 consecutive patients undergoing major knee surgery with postoperative analgesia obtained with a femoral catheter, a technique commonly used in our department. METHODS: Regional analgesia was induced after surgery with a bolus injection of 30 mL of 2% lidocaine with 1:200,000 epinephrine 1 in 200,000, maintained by continuous infusion of 1% lidocaine + morphine 0.03 mg.mL-1 + clonidine 2 micrograms.mL-1 for 48 h. The infusion rate was 0.1 mL.kg-1.h-1. The evaluation was based on: 1) the quality of analgesia at rest, at 30 min, h1, h3, h6, h12, h24 and h48; 2) the sensitive and motor blockade at the same time intervals. RESULTS: A "3 in 1" block was only observed in 50% of patients after the initial bolus via the femoral catheter. During the maintenance of analgesia with a continuous infusion a blockade of the three main nerves of the lumbar plexus occurred in less than 20% of patients after 6 h and was limited to the territory of the femoral nerve in 45 to 50% of patients after 12 to 48 h. In all cases the median values of VAS were below 42 mm. CONCLUSION: In most patients, a local anaesthetic administered continuously via a femoral catheter produces a blockade limited to the femoral nerve. These data do not substantiate the conclusions by those who consider they are producing a continuous "3 in 1" block with this technique. However, it is obviously not essential to produce a sensitive blockade of the three main nerves of the lumbar plexus to obtain an effective analgesia after knee surgery.     

Medicolegal pitfalls in the involuntary confinement of psychiatric patients in Louisiana

OBJECTIVES: Intravenous regional anesthesia (i.v.r.) is a safe, effective technique for surgery on the upper extremities, but it provides no postoperative analgesia. The aim of this study was to evaluate the analgesic efficacy of ketorolac during and after surgery with i.v.r. induced by lidocaine. PATIENTS AND METHODS: A double blind, placebo-controlled clinical trial. Twenty-six patients undergoing elective surgery on the upper extremities under i.v.r. were studied. In the anteroom of the operating theater, an anesthesiologist prepared the anesthetic solution to be administered from two syringes. One contained 3 mg/kg of 0.5% lidocaine (0.6 ml/kg). The second syringe (2 ml) contained 1 ml of 0.9% saline solution for the control group or 1 ml with 30 mg of ketorolac for the treatment group. A second anesthesiologist received the patient in the operating theater and used the syringes provided to induce the blockade. After releasing the pneumatic tourniquets we assessed the appearance of postoperative pain on a visual analog scale over the first 24 hours. The dats were compared using parametric (Student t test) and non parametric tests (Mann-Whitney U test and Fisher's exact test). RESULTS: No significant differences in the characteristics or hemodynamic parameters analyzed were found between the two groups. Nor did we find any differences in analgesia during surgery. Ten of the 13 patients (77%) in the control group required analgesia within the first two hours, whereas none of the patients in the treatment group required analgesia during that time (p < 0.0001). There were no statistically significant differences between the two groups in the total amount administered altogether, both during and after surgery. No local or systemic side effects were observed.     

Transarterial brachial plexus anesthesia for hand surgery: a retrospective analysis of 346 cases

STUDY OBJECTIVES: To study the safety and efficacy of the transarterial approach to brachial plexus block with 60 to 70 ml of local anesthetic solution, and to compare the success and complication rates of this block performed by experienced or inexperienced anesthesiologists. DESIGN: Retrospective analysis of 346 records of ASA physical status I-IV patients who underwent elective unilateral orthopedic upper limb surgery with transarterial plexus anesthesia. SETTING: University teaching hospital. MEASUREMENTS AND MAIN RESULTS: Blood pressure (BP) and heart rate were measured at 5-minute intervals. Analgesia was registered as successful, incomplete, or failed. Any patient complaints or adverse reactions were recorded. The first 60 ml of local anesthetic provided surgical analgesia to 64% of patients. With a supplemental 10 ml of anesthetic, the overall success rate was 94%, with only 19 of 346 patients requiring general anesthesia. Experience in performing the block increased the success rate from 90% to 98% (p < 0.001). Six patients experienced either nausea or a transient BP decrease that did not require medication. There was no record of toxic or other serious adverse reaction. CONCLUSIONS: Transarterial brachial plexus block administered with a 60 to 70 ml dose of local anesthetic provides surgical analgesia for hand surgery with an excellent success rate and without serious adverse effects.     

Subarachnoid anesthesia with minimal doses of lidocaine in ambulatory arthroscopic surgery of the knee

The objective is demonstrate that subarachnoid anesthesia with 2% isobaric lidocaine at low doses (0.5 mg/kg) is safe and effective for outpatient arthroscopic surgery of the knee. This was a prospective study of 150 ASA I-III patients undergoing arthroscopic knee surgery as outpatients under subarachnoid anesthesia. With no prior vascular filling, we provided blockade by administering 2% isobaric lidocaine at a dose of 0.5 mg/kg through a Sprotte 25G needle without vasoconstrictor. We assessed effectiveness and degree of sensory-motor blockade, cardiovascular repercussions, recovery time (until reversal of blockade, ambulation, micturition and discharge) as well as side effects observed. The mean dose of lidocaine used was 33.44 +/- 4.16 mg. The sensory-motor blockade achieved provided optimum conditions for prevention of ischemia and the practice of the surgical procedure in all cases. Surgery lasted a mean 38 +/- 10 min. Hemodynamic changes were not clinically significant and no patients additional fluids, atropine or vasopressors. Time from start of blockade until ambulation, micturition and discharge from the recovery unit were 123 +/- 8.3, 175 +/- 12.4 and 194 +/- 13.4 min, respectively. Micturition was spontaneous in all cases. Complications recorded were cephalea and backache. In conclusion, subarachnoid anesthesia at low doses of 2% isobaric lidocaine provides excellent conditions for practicing arthroscopic surgery of the knee on outpatients, with minimum side effects.     

Dose-response relationship of intrathecal morphine for postcesarean analgesia

BACKGROUND: This series investigated the quality of analgesia and the incidence and severity of side effects of intrathecal morphine for post-cesarean analgesia administered over a dose range of 0.0-0.5 mg. METHODS: ONE hundred eight term parturients undergoing cesarean delivery at term and given spinal anesthesia were randomized to receive a single dose of intrathecal morphine (0.0, 0.025, 0.05, 0.075, 0.1, 0.2, 0.3, 0.4, or 0.5 mg). A patient-controlled analgesia (PCA) device provided free access to additional analgesics. PCA morphine use, incidence and severity of side effects, and need for treatment interventions were recorded for 24 h. Data were analyzed with analysis of variance and linear regression analysis for trends among groups. RESULTS: Patient-controlled analgesia use differed significantly between groups; PCA use was higher in the control group than in groups receiving 0.075, 0.1, 0.3, 0.4, or 0.5 mg. Twenty-four-hour PCA morphine use was 45.7 mg lower (95% CI, 4.8-86.6 mg lower) in the 0.075-mg group than the control group. There was no difference in PCA morphine use between the 0.075- and 0.5-mg groups (95% CI, 36.8 mg lower to 45.0 mg higher); despite a fivefold increase in intrathecal morphine dose, PCA morphine use remained constant. There was no difference between control and treatment groups or among treatment groups with respect to nausea and vomiting. Pruritus and the need for treatment interventions increased in direct proportion to the dose of intrathecal morphine (linear regression, P = 0.001 and P = 0.0002, respectively). CONCLUSIONS: These data indicate there is little justification for use of more than 0.1 mg for post-cesarean analgesia. For optimal analgesia, augmentation [corrected] of intrathecal morphine with systemic opioids may be necessary.     

Postoperative analgesia after co-administration of clonidine and morphine by the intrathecal route in patients undergoing hip replacement

Postoperative analgesia after intrathecal co-administration of clonidine hydrochloride (75 micrograms) and morphine sulfate (0.5 mg) was compared with analgesia produced after either intrathecal morphine (0.5 mg) or 0.9% sodium chloride in 90 patients undergoing total hip replacement under bupivacaine spinal anesthesia. Patient-controlled morphine requirements were significantly reduced (P < 0.001) postoperation by both clonidine/morphine (median 5 mg/24 h) and morphine (median 7 mg/24 h) compared with control (saline) (median 28 mg/24 h). However, no significant additional reduction in postoperative analgesic requirements was shown with the clonidine/morphine combination compared with morphine alone. Visual analog pain scores, although good in all groups at all times, were significantly poorer in the control group at 2 h (P < 0.04) and 4 h (P < 0.001) after operation compared with both treatment groups, and significantly poorer than the clonidine/morphine group at 6 h (P < 0.002) and 24 h (P < 0.009) postoperation. Mean arterial blood pressure was significantly lower in the clonidine/morphine group than in the two other groups (P < 0.001) between 2 and 5 h after operation. The incidence of emesis was similar in the clonidine/morphine and morphine groups and was significantly more than in the control group.     

A comparison of 0.5% bupivacaine, 0.5% ropivacaine, and 0.75% ropivacaine for interscalene brachial plexus block

The onset time and duration of action of ropivacaine during an interscalene block are not known. The potentially improved safety profile of ropivacaine may allow the use of higher concentrations to try and speed onset time. We compared bupivacaine and ropivacaine to determine the optimal long-acting local anesthetic and concentration for interscalene brachial plexus block. Seventy-five adult patients scheduled for outpatient shoulder surgery under interscalene block were entered into this double-blind, randomized study. Patients were assigned (n = 25 per group) to receive an interscalene block using 30 mL of 0.5% bupivacaine, 0.5% ropivacaine, or 0.75% ropivacaine. All solutions contained fresh epinephrine in a 1:400,000 concentration. At 1-min intervals after local anesthetic injection, patients were assessed to determine loss of shoulder abduction and loss of pinprick in the C5-6 dermatomes. Before discharge, patients were asked to document the time of first oral narcotic use, when incisional discomfort began, and when full sensation returned to the shoulder. The mean onset time of both motor and sensory blockade was <6 min in all groups. Duration of sensory blockade was similar in all groups as defined by the three recovery measures. We conclude that there is no clinically important difference in times to onset and recovery of interscalene block for bupivacaine 0.5%, ropivacaine 0.5%, and ropivacaine 0.75% when injected in equal volumes. IMPLICATIONS: In this study, we demonstrated a similar efficacy between equal concentrations of ropivacaine and bupivacaine. In addition, increasing the concentration of ropivacaine from 0.5% to 0.75% fails to improve the onset or duration of interscalene brachial plexus block.     

The peripheral effect of fentanyl on postoperative pain

The clinical value of the analgesic effect of opioids administered peripherally (except for intraarticular administration) has not been clearly demonstrated. The aim of this study was to test the hypothesis that fentanyl, added to a local anesthetic for wound infiltration, can enhance postoperative analgesia via a peripheral mechanism. Patients with inguinal herniorrhaphy performed under spinal anesthesia were randomly assigned to one of two groups (n = 10 each). At the end of surgery, the wound was infiltrated with 10 mL of lidocaine 0.5% and fentanyl 0.001% (10 microg) in one group; in the other group, the wound was infiltrated with 10 mL of lidocaine 0.5% alone (and fentanyl 10 microg IM contralaterally). The following variables were determined in a double-blind manner: the duration of anesthesia (response to a von Frey filament), the duration of analgesia (time to mild postoperative pain), postoperative meperidine consumption, intensity visual analog scale of spontaneous and movement-associated pain 24 h after surgery, and wound pain threshold 24 h after surgery (pressure algometry). The addition of fentanyl for wound infiltration enhanced the duration of anesthesia (130+/-37 vs 197+/-27 min; P < 0.001) and decreased the intensity of spontaneous (50+/-17 vs 19+/-18 mm; P < 0.002) and movement-associated (56+/-15 vs 26+/-21 mm; P < 0.002) pain 24 h postoperatively. Differences between groups for other variables were not statistically significant. Fentanyl added to a local anesthetic for wound infiltration after spinal anesthesia can enhance postoperative analgesia by a peripheral mechanism. IMPLICATIONS: Fentanyl can enhance analgesia by a peripheral mechanism. Added to a local anesthetic for wound infiltration, it may be of benefit for the relief of postoperative pain.     

Long-term bone marrow culture profiles in patients with myelodysplastic syndromes are not explicable by defective apoptosis

PURPOSE: To compare intraoperative anaesthetic and haemodynamic effects of clonidine-bupivacaine, morphine-bupivacaine and placebo-bupivacaine combinations during continuous spinal anaesthesia. METHODS: Thirty six geriatric patients, undergoing knee replacement using continuous spinal anaesthesia were randomly assigned to: Placebo (n = 12), clonidine (n = 12) and morphine (n = 12), where 1 ml saline, 0.15 mg clonidine or 0.15 mg morphine were mixed with 10 mg bupivacaine 0.5%. Anaesthetic variables studied were maximal sensory level and degree of motor block, duration of surgical analgesia and duration of anaesthesia. Changes in systolic arterial pressure and vasopressor requirements were evaluated. RESULTS: Maximal sensory level and degree of motor block were comparable among the groups. Before surgery two patients in the placebo group, three in the clonidine and one in the morphine group received one additional ml bupivacaine 0.5% because of inadequate anaesthesia and were not considered for determination of duration of surgical analgesia. In the remainder, 1/9 in the clonidine group, 8/10 in placebo and 8/11 in morphine (P < 0.05) received reinjection of bupivacaine for surgical pain. These injections were given about 2 1/2 hr after the initial intrathecal injection, the duration of anaesthesia being about four hours. During the first 30 min after the initial injection the decrease in systolic pressure was greater in the clonidine and morphine than in the placebo group (P < 0.05). Thereafter, vasopressor requirements were higher only in the clonidine group (P < 0.05). CONCLUSION: In elderly patients 0.15 mg clonidine but not 0.15 mg morphine prolonged surgical analgesia when added to 10 mg plain bupivacaine.     

Measurement of pulmonary status and surfactant protein levels during dexamethasone treatment of neonatal respiratory distress syndrome

PURPOSE: To study the effect of epidural buprenorphine on minimum alveolar concentration (MAC) of volatile anaesthetics, duration of analgesia and respiratory function in the perioperative period. METHODS: One hundred and twenty patients, ASA I-II undergoing gynaecological surgery were randomly divided into three studies. The forty patients in each study were randomly divided into four groups depending on the dosage; Group I (control), Group II (80 micrograms. kg-1 morphine), Group III (4 micrograms. kg-1 buprenorphine), Group IV (8 micrograms. kg-1 buprenorphine). The MAC of halothane was measured following epidural administration of the agents in each group. The duration of analgesia was assessed by the first request for pentazocine. Postoperative analgesic effects were assessed by the total dosage of pentazocine required for the 48 hr after surgery. Respiratory rate (RR), minute volume (MV), and PaCO2 were measured during surgery and the postoperative period. The MAC of halothane was reduced in Group IV (P < 0.01). The duration of analgesia was 10.0 +/- 5.1 hr (Mean +/- SE) in Group I, 37.7 +/- 4.7 hr in Group II, 27.1 +/- 7.1 hr in Group III, and 44.4 +/- 4.1 hr in Group IV. Total dosage of pentazocine was lower in Group IV (P < 0.05) than in the other groups. The decrease of RR, MV and the increase of PaCO2 were observed within 60 min in Group III and IV dose dependently. CONCLUSION: Epidural buprenorphine administered in a dose of 4 or 8 micrograms. kg-1 provides postoperative analgesia that is no less effective than that of morphine.     

Clonidine added to bupivacaine-epinephrine-sufentanil improves epidural analgesia during childbirth

BACKGROUND AND OBJECTIVES: A double-blind study was conducted to assess the efficacy and the side effects of a low dose of clonidine added to an epidural injection of bupivacaine and epinephrine, with or without sufentanil. METHODS: One hundred healthy parturients (ASA 1) were randomly allocated into four groups according to the type of epidural analgesia administered. The bupivacaine/epinephrine (BE) group received a 10-mL standard injection of bupivacaine (B) 1.25 mg/mL and epinephrine (E) 1.25 microg/mL. In the bupivacaine/epinephrine/sufentanil (BES) group, 7.5 microg sufentanil (S) was added to the BE mixture. For the bupivacaine/ epinephrine/clonidine (BEC) group, 50 microg clonidine (C) was added to the BE mixture, whereas for the bupivacaine/epinephrine/sufentanil/clonidine (BESC) group, both sufentanil and clonidine were added to BE. Fetal heart rate was monitored by continuous cardiotocography. Duration of analgesia, method of delivery, and neonatal outcome (measured using APGAR score, peripheral oxygen saturation, and neurologic adaptive capacity score) and side effects of clonidine were observed. The parturients were routinely asked for their global appreciation of the epidural analgesia technique by visual analog score, 2 hours postpartum. RESULTS: The overall quality and duration of analgesia were superior in the BESC group compared with the other groups, as was the global appreciation by the parturient. The frequency of side effects in the clonidine groups was comparable, with the exception of hypotension and sedation. Hypotension was easily treated by fluids or ephedrine and caused no fetal distress. The level of sedation was mild, and all parturients aroused immediately after verbal commands. CONCLUSION: The addition of a low dose of clonidine to an epidural injection of bupivacaine with epinephrine and sufentanil provides better analgesia during labor, while keeping the side effects minimal and of minor clinical importance.     

Influence of anesthetic technique in postoperative analgesia in thoracic surgery

OBJECTIVE: To compare the intensity of postoperative pain after thoracotomy with 2 anesthetic techniques: 1) thoracic epidural block with bupivacaine administered before surgery (combined anesthesia with isoflurane) and 2) conventional balanced anesthesia with isoflurane and endovenous fentanyl. PATIENTS AND METHODS: Thirty patients scheduled for thoracotomy by lateral incision (T5-T6) were randomly divided into 2 groups of 15. Group A received 8 ml of 0.5% bupivacaine with adrenalin 1:200.000 30 min before start of surgery while group B received 8 ml saline solution through an epidural catheter inserted to T4-T8. Combined anesthesia (4 ml 0.5% bupivacaine through an epidural catheter 150 min after the first dose and isoflurane in 100% oxygen) was used in group A. Group B received balanced anesthesia with endovenous fentanyl 2.5 micrograms/kg and isoflurane in 100% oxygen. The difference in pain intensity during postoperative recovery was assessed by way of the following variables: number of boluses administered by epidural patient-controlled analgesia (bupivacaine 0.0625% and fentanyl 6 micrograms/ml); score on a visual analog scale of 10 at baseline and at 1, 3, 7, 11, 19 and 43 hours after surgery; and need for additional analgesia (diclofenac) during the 43 hours of study. Arterial gases were measured during the preoperative period and at 1, 3, 7, 19 and 43 hours after surgery. RESULTS: No significant differences in pain intensity measured on the visual analog scale, by the number of boluses per patients or by need for additional analgesia were found between the 2 groups. The total number of boluses administered and additional analgesic requirements were greater in the group receiving bupivacaine, although the difference was not significant (p = 0.095 and p = 0.056, respectively). Nor were there significant differences in pH and PaCO2 levels for the 2 groups. CONCLUSIONS: Analgesic efficacy after thoracotomy was similar for our 2 groups receiving either combined anesthesia (epidural bupivacaine at 0.5% and isoflurane) or balanced anesthesia with isoflurane and endovenous fentanyl.     

Role of imidazoline receptors in the cardiovascular actions of moxonidine, rilmenidine and clonidine in conscious rabbits

The present study in conscious rabbits with intracisternal (i.c.) catheters sought to determine the relative contribution of the I1 subtype of imidazoline receptors (IR) and alpha 2 adrenoceptors to the hypotensive effects of rilmenidine, clonidine and moxonidine with an I1-IR/alpha 2 adrenoceptor antagonist efaroxan and a specific alpha 2 adrenoceptor antagonist 2-methoxyidazoxan (2-MI). The alpha 2 adrenoceptor antagonist effect of efaroxan was compared with 2-MI by performing cumulative dose-response curves in the presence of alpha-methyldopa (400 micrograms/kg i.c.). 2-MI was 5.6 times more potent than efaroxan at reversing 75% of the hypotension elicited by alpha-methyldopa (P < .025). This dose ratio was used to match doses of efaroxan and 2-MI for similar alpha 2 adrenoceptor blockade. The effects of efaroxan (4.1, 13, 41 micrograms/kg i.c.) and 2-MI (0.74, 2.3, 7.4 micrograms/kg i.c.) were investigated on a single i.c. dose of rilmenidine (12 micrograms/kg), clonidine (0.75 microgram/kg) and moxonidine (0.51 microgram/kg). These doses of the antihypertensive agents, which were determined from cumulative dose-response curves, produce 90% of the maximum hypotension. Efaroxan was more effective at reversing the hypotension induced by moxonidine and rilmenidine than was 2-MI (P < .01). These findings suggest that rilmenidine and moxonidine act predominantly via IR. By contrast, 2-MI was more effective at reversing the clonidine-induced hypotension than was efaroxan (P < .001), suggesting that clonidine acts mainly via alpha 2 adrenoceptors in conscious normotensive rabbits. Thus, a higher selectivity of the second generation agents moxonidine and rilmenidine for I1-IR over alpha 2 adrenoceptors, compared with the first generation agent clonidine, appears to be necessary for this effect to be manifested in their hypotensive actions.