Epidural block for obstetrics: Comparison of bolus injection of local anesthetic with gravity flow technique

Study Objective: To test the hypothesis that slow administration of local anesthetic into the epidural space by gravity flow reduces the incidence of signs and symptoms of unintended injection.

Design: Prospective, randomized study.

Setting: Teaching hospital.

Patients: 600 ASA physical status I and II parturients scheduled for labor and delivery or elective cesarean section.

Interventions: After identification of the epidural space with pulsations of an air-fluid column, parturients for vaginal delivery (n = 380) were randomized to receive a test dose of 3 ml 3% 2-chloroprocaine with epinephrine 20 μg, two doses of 7 ml bupivacaine 0.03 % with sufentanil 1 μg/ml and epinephrine 2 μg/ml by either gravity flow (Group 1) given over 30 seconds or by bolus injection (Group 2) given over 5 seconds through the epidural needle; parturients for Cesarean delivery (n = 220) were randomized to receive a test dose and two doses of 6 ml lidocaine 2 % with sufentanil 1 μg/ml and epinephrine 2 μg/ml by either gravity flow or by bolus injection through the epidural needle. Changes in maternal heart rate (HR) and blood pressure, signs of intravascular injection, and adverse effects of epidural bupivacaine-sufentanil were recorded after each dose.

Measurements and Main Results: Gravity flow administration (Group 1) was associated with a smaller increase in mean maternal HR (p < 0.001), less hypotension (p < 0.01), sedation (p < 0.01), nausea (p = 0.01), and segmental spread (p < 0.0001) than were corresponding doses given by traditional bolus injection (Group 1) for vaginal or Cesarean deliveries. The incidence of systemic toxicity was zero of 300 (0%) with gravity flow and 4 of 300 (1.3%) by bolus injection, p = 0.12, Fisher's exact test. No patient in either group had an accidental intrathecal injection.

Conclusion: Gravity flow administration of local anesthetic-opioid solution during epidural block for obstetrics was associated with fewer signs of systemic drug absorption and cardiovascular perturbations than was the traditional bolus injection. This study supports the current opinion that slow administration of local anesthetic during epidural black contributes to fewer adverse events.     

An updated cross-referenced filing system for anesthesiologists.

A filing system that provides a medical-information retrieval system is useful for medical students, physicians-in-training, and practicing physicians. The present system is an expansion and update of the one proposed by Petty and Carden in 1973. This filing system for anesthesiologists contains a simple numerical index of the major categories in the anesthetic, medical, and surgical literatures. The organ system and the anesthetic considerations are combined. A cross-reference index is provided as well. This system allows the user to cross-file reprints, locate ones that have been loaned, and keep track of references that may be found in personal bound volumes. The files may be expanded over the years to any desired degree. Finally, this system may be of use either to the individual anesthesiologist or to a department's library.     

Conclusions from a study of venous invasion in stage IV colorectal adenocarcinoma

AIMS: Venous invasion is an established predictor of prognosis in colorectal cancer (CRC). The reported incidence of venous invasion in CRC specimens varies between 10% and 89.5%, mainly as a result of interobserver variability and differences in specimen processing (for example, staining with haematoxylin and eosin (H+E) alone versus the addition of an elastic fibre stain). This study was performed with three purposes in mind, namely: (1) To assess and compare the incidence of venous invasion diagnosed on H+E stained tissue versus tissue stained with both H+E and an elastic fibre stain. (2) To estimate the inherent false negative rate associated with the diagnosis of venous invasion by histopathological evaluation of resected CRC specimens. (3) To compare the resulting data regarding incidence, quantity, site, and type of venous invasion to the pertinent literature. METHODS: Venous invasion was assessed on sections from 81 CRCs resected from patients with synchronous distant metastases (hepatic and non-hepatic). Only stage IV tumours were studied for the following reasons: (1) it can be assumed that in all patients with distant haematogenous metastases venous invasion had occurred, thus enabling the false negative rate to be calculated; (2) there can be no dispute about the clinical relevance of the various characteristics of venous invasion identified in the tumours of patients with synchronous distant haematogenous metastases; and (3) to eliminate the effect of variance in tumour stage on the incidence of venous invasion. Initially, H+E stained sections were studied for venous invasion. Sections that were negative or questionable with regard to venous invasion were then stained with an elastic fibre stain, and a second search for venous invasion was carried out. Venous invasion was characterised by incidence, quantity, type, and site. The chi(2) test for independence was used to compare the incidence of venous invasion in colonic versus rectal and rectosigmoid primary tumours, and in patients with hepatic versus non-hepatic metastases. RESULTS: Venous invasion was identified in 42 (51.9%) (of the 81 specimens on H+E stained sections. The addition of the elastic fibre stain enabled the diagnosis of venous invasion in 15 (38.5%) of the remaining 39 specimens, increasing the overall incidence to 57 of 81 cases (70.4%). Of the 57 positive specimens, venous invasion was minimal in 27 (47.4%), intermediate in five, (8.8%) and massive in 25 (43.9%). Only intramural veins were involved in 18 (31.6%), only extramural veins in 26 (45.6%), and both intramural and extramural veins in 13 (22.8%) of the 57 positive specimens. The filling type of venous invasion was found in 41 (71.9%), the floating type in 28 (49.1%), and the infiltrating type in six (10.5%) of the 57 positive specimens. There was no significant difference between the incidence of venous invasion in the colon (42 of 60; 70%) versus rectal and rectosigmoid tumours (15 of 21; 71.4%; p = 0.8539), nor in the incidence of venous invasion in patients with hepatic (49 of 70; 70%) versus non-hepatic (eight of 11; 72.7%) metastases (p = 0.9018). CONCLUSIONS: The addition of an elastic fibre stain enables the identification of venous invasion in a considerable proportion of sections from CRC tumours that are falsely negative for venous invasion on H+E stain alone. The inherent chance of missing venous invasion on histopathological evaluation of CRC tumours stained with H+E and elastic fibre stains is at least 10.5%, and may be as high as 29.6%. In a large proportion of stage IV CRCs, despite the presence of synchronous distant metastases, only a minimal extent of venous invasion (that is, one to two involved veins) is demonstrable in the primary tumour. This suggests that only minimal venous invasion is required for the seeding of clinically relevant haematogenous metastases, and emphasises the careful, dedicated search for venous invasion that is required from the pathologist. Although extramural venous invasion was predominant in stage IV CRCs, in a considerable proportion of tumours (about a third) only intramural venous invasion was found. This suggests that intramural venous invasion may also seed clinically relevant haematogenous metastases, and should therefore also be considered as an indicator of poor prognosis.     

Study of a family with Cerebrotendinous Xanthomatosis. No HLA linkage, but an informative recombination between HLA-B and Bf

A large family with three children affected with the autosomal recessive disease of Cerebrotendinous Xanthomatosis (CTX) was studied for class I (HLA-A,B,C) and class II antigens (HLA-DR,D,SB), properdin factor B and glyoxalase. The extensive typing revealed an informative cross-over between HLA-B and Bf, indicating that Bf is located centromeric to the HLA-B locus and segregated in this family with HLA-D/DR. The parents in this family were first cousins and their parents were also first cousins. Three of their four haplotypes share B14, BfS, DR1, Dx and SB4 and may be identical by descent. The three affected children carried among them all four parental haplotypes, indicating that close linkage of the CTX locus to HLA is unlikely.     

Comparison of serum hepatitis C virus RNA and core antigen concentrations and determination of whether levels are associated with liver histology or affected by specimen storage time

An enzyme immunoassay has recently been developed for the hepatitis C virus (HCV) core antigen. To evaluate the possible association between core antigen and HCV RNA levels with regards to the change in liver histology over time as well as study the effect of duration of storage on viral load results, sequential sera were analyzed from 45 patients with chronic HCV infection who had undergone two or more liver biopsies. A relatively strong association was found between the core antigen and HCV RNA concentrations (r(s) = 0.8), with a core antigen level of 1 pg/ml corresponding to approximately 1,000 IU/ml. All 42 sera with detectable HCV RNA at the time of the second biopsy had core antigen concentrations above 1 pg/ml, and the three sera without detectable HCV RNA had concentrations below 1 pg/ml. No association was found between HCV RNA or core antigen levels and the stage of fibrosis in biopsy samples, progression of fibrosis, necro-inflammatory grade, steatosis, genotype, alanine aminotransferase level, or alcohol consumption. A significant association was demonstrated between the storage time of the samples and both the HCV RNA and core antigen concentrations. The median log HCV RNA concentrations (international units/milliliter) were 3.92 for the sera obtained at the time of the first biopsy (median storage time, 13.0 years) and 4.41 for the sera obtained at the time of the second biopsy (median storage time, 6.6 years) compared to 5.96, the median for 102 different routine clinical patient samples.