Sciatic nerve block with 0.5% levobupivacaine, 0.75% levobupivacaine or 0.75% ropivacaine

BACKGROUND AND OBJECTIVE

This prospective, randomized, double-blind study was conducted to evaluate the onset time and duration of sciatic nerve block produced with 0.5% levobupivacaine, 0.75% levobupivacaine and 0.75% ropivacaine.

METHODS

Forty-five healthy patients undergoing hallux valgus repair were randomly allocated to receive sciatic nerve block with levobupivacaine 0.5% (n=15), levobupivacaine 0.75% (n=15) or ropivacaine 0.75% 20 mL (n=15). A femoral nerve block was also performed with mepivacaine 2% 15 mL to cover pain related to the thigh tourniquet. A blinded observer recorded the onset time and duration of sciatic nerve block.

RESULTS

The median (range) onset time was 5 (5-40) min with 0.75% levobupivacaine, 30 (5-60) min with 0.5% levobupivacaine and 20 (5-50) min with 0.75% ropivacaine (P = 0.02 and P = 0.12, respectively). Mean (25-75 percentiles) first request for pain medication occurred after 13 (11-14) h with 0.75% ropivacaine, 18 (15-19) h with 0.75% levobupivacaine and 16 (13-20) h with 0.5% levobupivacaine (P = 0.002 and P = 0.002, respectively). Rescue tramadol after surgery was required by three patients in the 0.75% levobupivacaine group, eight patients in the 0.5% levobupivacaine group and nine patients in the 0.75% ropivacaine group (P = 0.05).

CONCLUSIONS

We conclude that 0.75% levobupivacaine provides a shorter onset time than 0.5% levobupivacaine and a longer duration of postoperative analgesia than both 0.5% levobupivacaine and 0.75% ropivacaine with reduced need for rescue analgesia after surgery.

Wash-in and wash-out curves of sevoflurane and isoflurane in morbidly obese patients

BACKGROUND

The aim of this prospective, randomized study is to compare sevoflurane and isoflurane pharmacokinetics in morbidly obese patients.

METHODS

With Ethical Committee approval and written informed consent, 14 obese patients (BMI >35 kg/m2), ASA physical status II, undergoing laparoscopic, silicone-adjustable gastric banding were randomly allocated to receive either sevoflurane (n=7) or isoflurane (n=7) as main anesthetic agents. General anesthesia was induced with 1 mg x kg-1 fentanyl, 6 mg x kg-1 sodium thiopental, and 1 mg x kg-1 succinylcholine followed by 0.4 mg kg-1 x h-1 atracurium bromide (doses were referred to ideal body weight). Intermittent positive pressure ventilation (IPPV) was applied using a Servo-900C ventilator with a nonrebreathing circuit and a 15 l x min-1 fresh gas flow (tidal volume: of 10 ml x kg-1; respiratory rate: 12 breaths/min; inspiratory to expiratory time ratio of 1:2) using an oxygen/air mixture (FiO2=50%), while supplemental boluses of thiopental or fentanyl were given as indicated in order to maintain blood pressure and heart rate values within +/-20% from baseline. After adequate placement of tracheal tube and stabilization of the ventilation parameters, 2% sevoflurane or 1.2% isoflurane was given for 30 min via a nonrebreathing circuit. End-tidal samples were collected at 1, 5, 10, 15, 20, 25 and 30 min, and measured using a calibrated infrared gas analyzer. General anesthesia was then maintained with the same inhalational agents, while supplemental fentanyl was given as indicated. After the last skin suture the inhalational agents were suspended, and the end tidal samples were collected at 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, and 5 min. Then the lungs were manually ventilated until extubation.

RESULTS

No differences in age, gender and body mass index were reported between the two groups. Surgical procedure required 91+/-13 in the sevoflurane group and 83+/-32 min in the isoflurane group. The FA/FI ratio was higher in the sevoflurane group from the 5th to the 30th min. Also the washout curve was faster in the sevoflurane group during the observation period; however, the observed differences were statistically significant only 30 and 60 sec after discontinuation of the inhalational agents.

CONCLUSIONS

The results of this prospective, randomized study confirmed that sevoflurane provides more rapid wash-in and wash-out curves than isoflurane also in the morbid obese patient.

[Levobupivacaine for peripheral blocks of the lower limb: a clinical comparison with bupivacaine and ropivacaine]

BACKGROUND

The aim of this study was the comparison of clinical profile of sciatic nerve block performed with either 0,5% levobupivacaine, 0,5% bupivacaine, or 0,5% ropivacaine.

METHODS

With ethical committee approval and written informed consent 45 ASA physical status I-II patients, undergoing elective hallux valgus repair received intravenous premedication with midazolam (0,05 mg/kg) followed by femoral nerve block with 15 ml of 2% mepivacaine. Then patients were randomly allocated to receive a sciatic nerve block with 20 ml of either 0,5% levobupivacaine (n=15), 0,5% bupivacaine (n=15), or 0,5% ropivacaine (n=15). An independent blind observer evaluated the onset time and duration of nerve block and postoperative analgesia. Postoperative analgesia consisted of 100 mg IV ketoprofen every 8 hours with the first administration at request.

RESULTS

The onset time of sciatic nerve block was 15 (5-60) min with levobupivacaine, 30 (5-60) min with bupivacaine, and 15 (5-60) min with ropivacaine (P = NS). No differences in the quality of nerve block as well as in the nerve block resolution times were observed among the three groups. The duration of postoperative analgesia was 16 (8-24) hours with levobupivacaine, 14 (8-24) hours with bupivacaine, and 17 (8-24) hours with ropivacaine (P=NS).

CONCLUSIONS

Using 0,5% levobupivacaine for sciatic nerve block results in similar clinical effects as those produced by using the same volume and concentration of either bupivacaine or ropivacaine.

Ropivacaine

BACKGROUND

Ropivacaine is a relatively new long-acting local anesthetic. It is a pure S(-) isomer, with a high pKa and low lipid solubility. Because of its physical and chemical properties, ropivacaine produces a marked differential in sensory and motor blockades, with a toxic potential lower than other long-acting anesthetic solutions. The purpose of this paper was the evaluation of the literature concerning indications and advantages of ropivacaine for different regional anesthesia techniques.

METHODS

We have evaluated results of prospective, randomized, controlled trials evaluating clinical use of ropivacaine for epidural anesthesia and analgesia, as well as spinal and peripheral nerve blocks.

RESULTS

The literature clearly demonstrates both efficacy and safety of ropivacaine used for epidural anesthesia and analgesia as well as for upper and lower limb peripheral nerve blocks, both single-shot and continuous peripheral blocks. Although ropivacaine has not been registered yet for spinal anesthesia, various studies show its efficacy and safety also in this field. Because of its pharmacodynamic properties, intrathecal ropivacaine seems also interesting for outpatient procedures.

CONCLUSIONS

Ropivacaine is a long-acting local anesthetic with a marked differential blockade between sensory and motor fibres, overall at the low concentrations used for postoperative analgesia. It probably has a slightly lower potency as compared with bupivacaine, but provides similar clinical efficacy in the different fields of regional anesthesia. Ropivacaine is less cardiotoxic and causes less central nervous system toxicity than bupivacaine, and this lower toxic potential has been reported not only with equivalent but also with equipotent concentrations and doses. For this reason, ropivacaine represents a useful alternative to bupivacaine for central and peripheral nerve blocks as well as for the management of postoperative pain relief.

Implementing sevoflurane anesthesia with small doses opioid for upper abdominal surgery. Postoperative respiratory function after either remifentanil or fentanyl

BACKGROUND

The aim of this prospective, randomized study was to compare the effects on intraoperative cardiovascular homeostasis, recovery profile and postoperative oxygen saturation after sevoflurane anesthesia with small doses of either remifentanil or fentanyl in combination with postoperative epidural analgesia.

METHODS

With Ethical Committee approval and written patient consent, 30 ASA physical status I-II patients scheduled for elective upper abdominal surgery were randomly allocated to receive sevoflurane general anesthesia implemented with small doses of either remifentanil (n = 15) or fentanyl (n = 15), followed by postoperative epidural analgesia. Remifentanil group patients received a 1 mg kg-1 bolus infused during a 60 sec period followed by a 0.15 mg kg-1 min-1 infusion; while patients of Fentanyl group were given a 3 mg kg-1 initial dose followed by 50 mg boluses as requested (according to the time to peak effect of the two drugs, the initial dose was given 5 min before induction in Fentanyl group, and 1 min before induction in Remifentanil group). Postoperatively, oxygen saturation was continuously recorded and stored on a computer during the first 12 h after surgery. SpO2 decrease < 90% for more than one minute was considered as a minor respiratory complication.

RESULTS

The median sevoflurane's MAC-hour was 2.7 (1.4 - 4.9) in patients receiving remifentanil infusion and 4.1 (2.2 - 5.7) in those patients receiving fentanyl during surgery (P = 0.005). However, no differences in the recovery times were observed between the two groups. Similar pain relief was reported during coughing in the two studied groups at discharge from the recovery area and during the following study period. No major respiratory complication was observed throughout the study. Oxygen therapy was required in three patients of Fentanyl group only 20% (P = 0.22); however, 11 patients in the same group (73%) showed at least one minor respiratory complication (SpO2 < 90% for more than 1 min), with a median of 1 (range 0 - 12) episode per patient, compared with no episode in Remifentanil group (P = 0.0005).

CONCLUSIONS

Implementing sevoflurane anesthesia with very small remifentanil infusion provides a safe and effective hemodynamic control reducing sevoflurane consumption during the procedure, and produces less respiratory effects postoperatively as compared with intermittent bolus administration of fentanyl.

Unexplained habitual abortion is associated with a reduced endometrial release of soluble intercellular adhesion molecule-1 in the luteal phase of the cycle

Although the mechanisms causing recurrent spontaneous abortion (RSA) remain frequently speculative, recent evidence indicates that a specific uterine immune-endocrine network plays a pivotal role in the continuation of pregnancy. We have recently demonstrated that an adhesion molecule of the immune system, named intercellular adhesion molecule (ICAM)-1, is markedly expressed at both protein and mRNA levels in endometrial stromal cells and is able to mediate their interaction with lymphoid cells. Moreover, we have shown that the soluble form of ICAM-1 (sICAM-1) can be released by the endometrium in a hormone-dependent manner. The present study was designed to determine whether surface and/or sICAM-1 expression by cultured endometrial stromal cells could be related to early pregnancy loss in patients with a history of unexplained RSA. Luteal-phase endometrial biopsies were obtained from eight patients who had experienced three or more consecutive unexplained RSAs in the first trimester and 12 control fertile women. Surface ICAM-1 was similarly expressed on luteal-phase endometrial cells obtained from women with and without a history of unexplained RSA. In contrast, the endometrial release of sICAM-1 was significantly lower in abortion-prone patients than in control women. sICAM-1 is a cytokine-inducible molecule able to interfere with several immunological responses and the reduced levels of the protein shed by the endometrium in patients who have suffered from unexplained RSAs may reflect the presence of an altered immunological environment during the early phases of pregnancy.

Dynamic aspects of endometriosis in a mouse model through analysis of implantation and progression

The aim of this study was to use normal immunocompetent mice to set up a model for endometriosis which allowed to study the dynamic aspects involved in initiation and progression of the disease. Thirty mice were surgically transplanted with autologous endometrium and at 3 weeks showed evidence of endometriosis. Diagnosis of endometriotic lesions was histologically confirmed. Visual inspection using a caliper revealed that, after an initial decrease in size (from 33.44+/-2.33 mm2 to 24.24+/-2.37 mm2 (p<0.01)) detected at 3 weeks after transplantation, there was a significant increase of lesion area from 21.30+/-3.15 mm2 to 43.93+/-6.29 mm2 (p<0.05) in the following 4 weeks. When we compared these results to those obtained in mice which underwent bilateral annessiectomy, we observed that, when bilateral annessiectomy was performed simultaneously to endometrial transplantation, lesion surfaces were similar between mice which were or were not subjected to bilateral ovariectomy. On the other hand, when bilateral annessiectomy was performed at second laparotomy and then evaluated after 4 weeks, differently from what observed in control mice, surface values decreased from 21.24+/-2.29 mm2 to 10.58+/-3.40 mm2 (p<0.01). Finally, progression of lesions in estrogen supplemented mice seems less evident than in control mice since only a slight but not significant increase in size (from 21.32+/-3.32 mm2 to 26.18+/-6.98 mm2, p=0.32) was detected. The results presented herein demonstrate that surgically induced endometrial implants in mice are dynamic lesions and that implantation and progression of endometriosis represent different stages in the ethiopathogenesis of the disease. Moreover, we showed that progression, but not implantation, of ectopic endometrium is dependent upon the functionally and structurally integrity of the ovaries. This is a model of endometriosis established in normal immunocompetent mice, and, consequently, may represent a reliable tool for testing new immunological therapeutical approaches and studying the role of different genes using transgenic mice.

Expression of GnRH receptor gene in human ectopic endometrial cells and inhibition of their proliferation by leuprolide acetate

The present study was conducted to investigate whether GnRH-receptor (GnRH-R) gene is expressed in endometriosis ovarian implants and whether a GnRH-analogue (GnRH-a) may exert an effect on endometriosis cell proliferation in vitro. The presence of GnRH-R transcripts in ovarian endometriosis cells was assessed by reverse transcription-polymerase chain reaction (RT-PCR) and further confirmed by Southern blot analysis. GnRH-R mRNA was detected in all the 13 samples examined. In contrast, GnRH-R transcripts were not detectable in endometriosis-free peritoneal tissue. In the second part of the study, endometriosis cells were cultured for 9 days with different doses of leuprolide acetate (ranging from 0 to 10(-5) M). In 4 out of 13 cases, a significant anti-proliferative effect was observed at doses of leuprolide acetate ranging from 10(-9) to 10(-5) M. In one case, a significant inhibition of cell proliferation was observed only at 10(-5) M leuprolide acetate concentration. In contrast, the GnRH-a did not affect cell growth, regardless of the expression of GnRH-R transcripts and the given doses, in the remaining 8 experiments. To date, this is the first evidence indicating that GnRH-R mRNA is expressed in human ovarian endometriomas. Moreover, the inhibition of endometriosis cell proliferation induced by the GnRH-a in vitro suggests that, at least in some cases, this compound might exert a direct effect on endometriosis lesions.

Endometrial release of soluble intercellular adhesion molecule 1 and endometriosis: relationship to the extent of the disease

OBJECTIVE

To relate endometrial release of the soluble form of intercellular adhesion molecule 1 with extent of endometriosis.

METHODS

Samples of endometrium were collected from 23 women with endometriosis. Soluble intercellular adhesion molecule 1 was quantified in conditioned medium from 48-hour endometrial stromal cell cultures with use of a specific enzyme-linked immunosorbent assay. Levels were correlated with revised American Society for Reproductive Medicine classification score for adhesions, implants, and cysts and total score; number of endometriotic implants; cyst diameter; and presence or absence of pelvic pain symptoms and previous surgical procedures for endometriosis.

RESULTS

Endometrial release of soluble intercellular adhesion molecule 1 directly correlated with number of implants (r = .64, P < .005) and score for implants (r = .61, P < .005). There was no significant correlation between levels of the soluble molecule and score for adhesions or total score. Soluble intercellular adhesion molecule 1 shed by endometrium did not correlate with the score for ovarian cysts, although an inverse relationship was found with ovarian cyst diameter (r = -0.52, P < .05). No differences were detected between women who had pelvic pain and those who did not and between those who had previous surgery for endometriosis and those who had not.

CONCLUSION

The association between endometrial release of soluble intercellular adhesion molecule 1 and the number and score of endometriotic implants suggests that the molecule might be of value in evaluating spread potential of refluxed endometrium.