Minimum effective anesthetic concentration (MEAC) for sciatic nerve block: subgluteus and popliteal approaches

BACKGROUND: We tested the hypothesis that using a subgluteus approach to the sciatic nerve requires a lower concentration of mepivacaine to obtain complete anesthesia as compared with the popliteal approach. METHODS: With midazolam premedication (0.05 mg kg(-1) iv), 48 patients undergoing hallux valgus repair were randomly allocated to receive a sciatic nerve block using either a posterior popliteal (group Popliteal, n = 24) or subgluteus (group Subgluteus, n = 24) approach with 30 mL of local anesthetic injected after elicitation of plantar flexion of the foot with a current 相似文献   

Aluminium interference in the treatment of haemodialysis patients with recombinant human erythropoietin

In nine chronic haemodialysis patients a desferrioxamine (DFO) load test (40 mg/kg body-weight) was performed 1 year after the beginning of treatment with recombinant human erythropoietin (rHuEpo). The patients were then divided into two groups. Group A comprised five patients with a greater mean aluminium (204 +/- 28 micrograms/l) than the four patients in group B. Group A was given a mean dose of 25.8 g (range 14-39 g) of DFO over 6 months. Group B (aluminium values 112 +/- 36 micrograms/l) was never treated with DFO. During the period of observation, plasma iron, serum ferritin and transferrin, as well as iron supplementation, did not differ between the groups. After DFO treatment a second DFO load test was performed. The mean predialysis aluminium value was significantly reduced in group A (204 +/- 28 vs 111 +/- 72 micrograms/l; P less than 0.05), while remaining unchanged in group B (112 +/- 36 vs 140 +/- 39 micrograms/l; P = ns). In both groups, the doses of rHuEpo necessary to maintain the same haemoglobin values decreased with time, but reduced significantly only in group A (298 +/- 105 vs 110 +/- 61 mu/kg per week; delta -63%; P less than 0.01). Thus, aluminium interferes with the response to rHuEpo in haemodialysis patients, and the correction of aluminium overload with DFO can allow a considerable sparing of rHuEpo.     

Immunohistochemical pattern of hMSH2/hMLH1 in familial and sporadic colorectal, gastric, endometrial and ovarian carcinomas with instability in microsatellite sequences

Alterations of DNA mismatch repair (MMR) genes are involved in carcinogenesis of sporadic and inherited human cancers characterised by instability of DNA microsatellite sequences (MSI). MSI tumours are usually identified using molecular analysis. In the present investigation, hMLH1 and hMSH2 immunohistochemistry was tested in order to evaluate the utility of this method in predicting MMR deficiency. Colorectal (72), gastric (68), endometrial (44) and ovarian (17) carcinomas were independently evaluated for familial history, histological type of tumour, MSI status and immunohistochemical results. Loss of expression of either hMLH1 or hMSH2 was observed in 51 of 55 (92.8%) MSI tumours, while 145 of 146 microsatellite stable (MSS) tumours expressed both the hMLH1 and hMSH2 gene products. Independently of tumour site, an overall agreement between immunohistochemical and molecular results was observed in 15 hereditary non-polyposis colorectal cancer-related tumours. Among sporadic tumours, only 2 of 60 colorectal and 2 of 66 gastric carcinomas, displaying MSI, expressed both hMLH1 and hMSH2 gene products. All 39 endometrial and 16 ovarian tumours presented a concordant molecular and immunohistochemical profile. These data show that immunohistochemistry is an accurate and rapid method to predict the presence of defective DNA MMR genes and to identify both sporadic and familial MSI tumours.     

Ropivacaine or 2% mepivacaine for lower limb peripheral nerve blocks. Study Group on Orthopedic Anesthesia of the Italian Society of Anesthesia, Analgesia, and Intensive Care

BACKGROUND: Intra- and postoperative clinical properties of sciatic-femoral nerve block performed with either ropivacaine at different concentrations or mepivacaine have been evaluated in a multicenter, randomized, blinded study. METHODS: Adult patients scheduled for foot and ankle surgery were randomized to receive combined sciatic-femoral nerve block with 225 mg of either 0.5% (n = 83), 0.75% (n = 87), or 1% (n = 86) ropivacaine, or with 500 mg of 2% mepivacaine (n = 84). A thigh tourniquet was used in all patients. Onset time, adequacy of surgical anesthesia, time to offset of nerve block, and time until first postoperative requirement for pain medication were evaluated by a blinded observer. RESULTS: The adequacy of nerve block was similar in the four treatment groups (the ratios between adequate:inadequate: failed blocks were 74:9:0 with 0.5% ropivacaine, 74:13:0 with 0.75% ropivacaine, 78:8:0 with 1% ropivacaine, and 72:12:0 with 2% mepivacaine). The onset of the block was slower with 0.5% ropivacaine than with other anesthetic solutions (P < 0.001). Regardless of the concentration, ropivacaine produced a longer motor blockade (10.5+/-3.8 h, 10.3+/-4.3 h, and 10.2+/-5.1 h with 0.5%, 0.75%, and 1% ropivacaine, respectively) than with mepivacaine (4.3+/-2.6 h; P < 0.001). The duration of postoperative analgesia was shorter after mepivacaine (5.1+/-2.7 h) than after ropivacaine (12.2+/-4.1 h, 14.3+/-5 h, and 14.5+/-3.4 h, with 0.5%, 0.75%, or 1% ropivacaine, respectively; P < 0.001). Pain relief after 0.5% ropivacaine was 14% shorter than 0.75% or 1% ropivacaine (P < 0.05). During the first 24 h after surgery, 30-37% of patients receiving ropivacaine required no analgesics compared with 10% of those receiving mepivacaine (P < 0.001). CONCLUSIONS: This study suggests that 0.75% ropivacaine is the most suitable choice of local anesthetic for combined sciatic-femoral nerve block, providing an onset similar to mepivacaine and prolonged postoperative analgesia.     

Anaesthesia for ultrasound guided oocyte retrieval: midazolam/remifentanil versus propofol/fentanyl regimens

To evaluate the quality of intra-operative anaesthesia and recovery characteristics of two different anaesthesia regimens, 60 healthy women undergoing ultrasound guided oocyte retrieval for in vitro fertilization procedures were randomly allocated to receive either a propofol/fentanyl or a midazolam/remifentanil based anaesthesia. The surgical procedure was successful in all patients and no severe side effects were reported by any patient. Four patients in the midazolam/remifentanil group (13%) would not accept the same anaesthetic procedure for further in vitro fertilization treatment due to intra-operative awareness, while all propofol/fentanyl patients were prepared to accept the same procedure again (P < 0.05). Patients in the propofol/fentanyl group required manual ventilation more frequently through a facemask than those patients treated with the midazolam/remifentanil combination (50% and 30%, respectively; P < 0.05). The time to achieve an Aldrete's score of 10 was shorter in the midazolam/remifentanil patients (2 +/- 2 min) than in those who received propofol/fentanyl (4 +/- 2 min) (P < 0.001), but no differences were observed in the time required to be 'fit to discharge' from the post-anaesthesia care unit. We conclude that the use of a midazolam/remifentanil regimen is as effective and safe as a fentanyl/propofol regimen in patients undergoing transvaginal oocyte retrieval for in vitro fertilization procedures.     

Effects of pneumoperitoneum and reverse Trendelenburg position on cardiopulmonary function in morbidly obese patients receiving laparoscopic gastric banding

We prospectively evaluated the effects of pneumoperitoneum and reverse Trendelenburg position on cardiopulmonary function in 20 ASA physical status II-III morbidly obese patients (body mass index > 35 kg m(-2)) undergoing laparoscopic gastric banding. After general anaesthesia was induced, patients' lungs were ventilated using intermittent positive pressure ventilation (at measurement times, the following parameters were used: tidal volume 12 mL kg(-1) ideal body weight, respiratory rate of 12 bpm, an inspiratory to expiratory time ratio of 1:2). Haemodynamic variables, blood gas parameters, and lung/chest compliance were recorded: in the supine position, after induction of general anaesthesia (T0, baseline) and induction of pneumoperitoneum (T1); after placing the patient in a 25 degree reverse Trendelenburg position (T2); during the surgical time (T3); before deflating the abdomen (T4); after pneumoperitoneum resolution (T5), and before the end of anaesthesia, with the patient supine (T6). The PaO2, PaO2/FiO2 ratio, and lung/chest compliance decreased during the study. After the pneumoperitoneum had been resolved, lung/chest compliance but not oxygenation parameters returned to baseline values. The arterial to end-tidal CO2 tension difference progressively increased from 0.38+/-0.3 kPa (2.85+/-2.25 mmHg) (T0) to 0.63+/-0.3 kPa (4.73+/-2.25 mmHg) (T6). In morbidly obese patients, undergoing laparoscopic gastric banding, a CO2 pneumoperitoneum markedly affected gas exchange and lung/chest compliance, while positioning the patient in a 25 degree reverse Trendelenburg position had no beneficial effects.     

Refinement of the colony-forming unit-megakaryocyte (CFU-MK) assay for its application to pharmaco-toxicological testing.

In vitro colony-forming unit (CFU) assays can be used in the evaluation of potentially haematotoxic compounds during preclinical testing. The use of undifferentiated haematopoietic cells, able to proliferate and commit towards a specific blood cell lineage, enable selective toxicity to be detected. We optimized the colony-forming unit-megakaryocyte (CFU-MK) assay for toxicological applications. We used a collagen-based colony-forming assay to examine the sensitivity of four cell types: mononuclear human cord blood cells (CBC), mononuclear human bone marrow cells (BMC), cord blood enriched CD34+CD38- cells, and bone marrow enriched CD34+CD38- cells, to the toxic effects of five drugs known to cause thrombocytopenia in humans. The enrichment of CD34+CD38- cells was achieved by using a negative cell separation technique. Our results showed that a comparable toxicity was detected both with CBC, BMC and CD34+CD38- cells enriched from cord blood, whereas CD34+CD38- cells from bone marrow were more resistant to some drugs. The assay showed a high reproducibility of the endpoint measured (IC(50)), independently of the cell type used and donor source. The present study demonstrates that the refined CFU-MK assay is reproducible and can be used for in vitro toxicology studies with CBC as well as BMC.