Effects of age on minimum effective volume of local anesthetic for ultrasound-guided supraclavicular brachial plexus block.

BACKGROUND: Involutional changes of peripheral nervous system occur with aging. The aim of the study was to determine the minimum effective volume of local anesthetic required to offer an effective ultrasound-guided supraclavicular brachial plexus block in 50% of middle-aged (< 50 years) and elderly (> 65 years) patients. We hypothesized reduced minimum effective volume of local anesthetic in elderly patients. METHODS: Middle-aged (n = 22) and elderly (n = 22) patients undergoing upper limb surgery received an ultrasound-guided supraclavicular brachial plexus block. Structural analysis of the brachial plexus in supraclavicular region was obtained by measuring the cross-sectional area. The prospective, observer-blinded study method is a previously validated step-up/step-down sequence model where the local anesthetic volume for the next patient is determined by the outcome of the previous block. The starting volume was 30 ml (50 : 50 mixture, 0.5%wt/vol levobupivacaine, 2%wt/vol lidocaine). The minimum effective volume of local anesthetic was determined using Dixon and Masey method. RESULTS: The minimum effective local anesthetic volume significantly differed between middle-aged and elderly [23.0 ml, 95% confidence interval (CI) 13.7-32.3 vs. 11.9 ml, 95% CI 9.3-14.6; 95% CI of the difference 1.6-20.6, P = 0.027]. The cross-sectional area of brachial plexus was 0.95 ± 0.15 in middle-aged and 0.51 ± 0.06 cm(2) in elderly patients (P < 0.001). CONCLUSIONS: Within the present study, we report a reduced minimum effective anesthetic volume for ultrasound-guided supraclavicular block in elderly patients. Additionally, smaller cross-sectional surface area of brachial plexus in the supraclavicular region was observed.

Spinal anesthesia at the L2-3 and L3-4 levels: comparison of analgesia and hemodynamic response.

Aim of this study was to evaluate level of analgesia and hemodynamic response to spinal anesthesia obtained by administering 15 mg 0.5% isobaric bupivacaine at L2-3 vs. L3-4 interspace for inguinal herniorrhaphy, since studies comparing analgesia and hemodynamic response at the L2-3 vs. L3-4 interspaces are lacking. In a prospective, randomized clinical study that encountered 72 patients undergoing elective inguinal herniorrhaphy randomly allocated in to two equal groups L2-3 (N = 36) and L3-4 (N = 36) according to lumbar interspace where intrathecal injection of bupivacaine was administered. Analgesia was evaluated by intraoperative "rescue" fentanyl requirements, the absence of pain and the maximal visual analogue scale (VAS) scores reached per patient during the operation. The severity of intraoperative pain was quantified by a 10 cm VAS scale (VAS 0: no pain to 10: worst pain imaginable) every 5 minutes after skin incision until the end of the operation. VAS > 3 was treated with intravenous fentanyl 25 microg. Hemodynamic response was monitored and evaluated, heart rate was continuously monitored as well as, baseline systolic, diastolic and mean arterial pressure prior to induction and every 5 minute after applying spinal anesthesia until surgical completion. Intraoperative fentanyl requirements were significantly higher in group L3-4 (L2-3 0%, 97.5% confidence interval [CI] 0.0-0.11 vs. L3-4 17%, 95% CI 0.07-0.32, p = 0.025). Absence of pain was significantly higher in L2-3 group at the beginning of the operation (L2-3 89%, 95% CI 0.74-0.96 vs. L3-4 67%, 95% CI 0.50-0.79, p = 0.047). The maximal VAS scores reached per patient during the operation in L2-3 group were lower then in L3-4 group (L2-3 median [M] 0, range [R] 0-3, L3-4 M 0, R 0-8, p = 0.014). There were no significant differences (p > 0.05) in the incidence of hypotension (L2-3 19%, 95% CI 0.09-0.35 vs. L3-4 17%, 95% CI 0.07-0.32) and bradycardia (L2-3 19%, 95% CI 0.09-0.35 vs. L3-4 8%, 95% CI 0.02-0.23). Spinal anesthesia with isobaric bupivacaine administered in L2-3 interspace for inguinal herniorrhaphy provides superior analgesia and equal hemodynamic stability as compared to neuroaxial anesthesia administered in the L3-4 interspace.

Successful management of unsuspected retroperitoneal paraganglioma via the use of combined epidural and general anesthesia: a case report.

INTRODUCTION: Similar to pheochromocytomas, paragangliomas can secrete catecholamines, although they are usually non-functional and clinical presentation is non-specific. We present a case of accidental, intra-operatively diagnosed neuroendocrine-active sympathetic paraganglioma, which was suspected and confirmed during elective retroperitoneal tumor removal. CASE PRESENTATION: A 25-year-old Caucasian Croatian man, American Society of Anesthesiologists status 1, underwent elective surgery for retroperitoneal tumor removal. The tumor had been discovered by chance during a routine examination and was suspected to be a sarcoma. Our patient had no history of previous medical conditions nor did he have symptoms characteristic of a neuroendocrine secreting tumor. The results of ultrasound and magnetic resonance imaging studies showed a large, well demarcated retroperitoneal tumor mass in his upper abdomen localized between the aorta and vena cava, measuring approximately 9×6×4.5cm. In the operating room an epidural catheter was inserted at the T7 to T8 level prior to induction of general anesthesia. Epidural analgesia was maintained by an infusion pump with local anesthetic and opiate mixture. During the surgical excision of the tumor, hemodynamic changes occurred, with hypertension (205/110mmHg) and tachycardia (up to 120 beats/minute). In spite of the fact that the surgical field of work did not include adrenal glands whose direct manipulation could explain this occurrence, there was a high degree of suspicion for the presence of a neurosecreting tumor. His clinical symptoms were relieved after administration of urapidil, esmolol and magnesium sulfate. After tumor excision, our patient developed severe hypotension. Hemodynamic stability was reinstated with aggressive volume replacement, with crystalloids and colloids, vasopressors and hydrocortisone. His post-operative course was unremarkable and on the eighth post-operative day our patient was discharged from hospital, with no consequences or symptoms on follow-up two years after surgery. CONCLUSIONS: Our patient's case emphasizes the need to consider the presence of extra-adrenal paragangliomas in the differential diagnosis of retroperitoneal tumors, despite their rare occurrence. In our patient's case, invasive hemodynamic monitoring during combined general anesthesia and epidural analgesia and early recognition of catechol-induced symptoms raised suspicion of the existence of a paraganglioma, and this led to an adequate therapeutic approach and favorable outcome of the surgery. Pre-operative recognition of paragangliomas could lead to better pre-operative preparation, but even high clinical suspicion in undiagnosed forms during surgery and the availability of rapid and short-acting vasodilatators, α-blockers and ß-blockers might favor good outcome.

Treatment of bleeding after kidney biopsy with recombinant activated factor VII.

Recombinant activated factor VII (rFVIIa) is approved for prevention and treatment of bleeding in hemophilia patients with inhibitors to FVIII (hemophilia A) or IX (hemophilia B), patients with congenital and acquired hemophilia and in patients with FVII deficiency or Glantzmann thrombasthenia (last indication is approved only in Europe). Off-labeled, the drug has been prescribed for prevention, or treatment of bleeding in severe hepatic disease, neonatal coagulopathies, high-risk surgical procedures, trauma, thrombocytopenia and platelet function disorders, as well as for urgent reversal of oral anticoagulation. Here we report a case of a 53-year-old female patient with delayed graft function after kidney transplantation, who had kidney biopsy complicated with prolonged bleeding. After unsuccessful treatment with desmopressin, the patient was treated with rFVIIa and the bleeding stopped immediately. Only few anecdotal reports of use of rFVIIa for treatment of bleeding in uremic patients have been published thus far. To our knowledge, this is the first case that describes use of rFVIIa for management of bleeding as a complication of renal biopsy in a uremic patient in the early kidney posttransplantation period.