Association of obesity with failure of ultrasound-guided axillary brachial plexus block: a two-centre, prospective, observational, cohort study.

The objective of this study was to evaluate whether the failure rate of ultrasound-guided axillary brachial plexus block is similar in obese patients compared with non-obese patients when performed as the primary anaesthetic technique. We recruited 105 obese (body mass index ≥ 30 kg.m-2 ) and 144 non-obese patients to this prospective, observational, cohort study conducted at two Canadian centres. A perineural technique of axillary brachial plexus block was performed using 30 ml ropivacaine 0.5% under real-time ultrasound guidance. Sensory and motor block assessment was carried out every 5 min until 30 min after block completion in all four terminal nerve distributions (radial, median, ulnar and musculocutaneous nerve). A composite score consisting of three sensory points and three motor points was used for assessment in each nerve distribution. A failed block was defined as a score of less than 14 points out of a possible 16 points, or a sensory block score less than 7 out of 8 points 30 min after block completion. Thirty minutes after block completion, obese patients had a higher failure rate of 33.7% (34/101) compared with 17.8% (24/135) for non-obese patients, with a failure rate difference (95%CI) of 15.9% (6.4-27.1%) between the groups. The median (IQR [range]) time to achieve a successful block in obese patients was 25 (20-30 [5-30]) min, compared with non-obese patients at 20 (15-30 [5-30]) min (p = 0.003). Despite a higher sensory-motor failure rate as per the composite score, the axillary brachial plexus block provided adequate surgical anaesthesia as indicated by a low need for conversion to general anaesthetic in obese (8.6%) and non-obese patients (7.0%; p = 0.656). This study showed that despite ultrasound guidance, obese patients had a slower onset time and higher axillary brachial plexus block failure rate at 30 min compared with non-obese patients.

Clinical value of sentinel node mapping in carcinoma of the colon.

AIM: Sentinel lymph node mapping has been used in colon cancer to improve prognosis. This study aimed to determine the accuracy of in vivo SLNM in patients with colon carcinoma undergoing surgery with curative intent. METHOD: Thirty-one patients operated for colon carcinoma underwent in vivo sentinel lymph node mapping using patent blue dye. Each sentinel lymph node (SLN) was marked intraoperatively, and histological examination was performed after en bloc resection. If no metastasis was found, step sectioning with immunohistochemistry was performed. RESULTS: The SLN was successfully identified in 28 (90%) of 31 patients. The false-negative rate to identify stage III disease was 66% (eight of 12), the negative predictive value was 46% (19 of 27) and the accuracy was 14% (four of 28). One patient negative on routine histopathology had micrometastasis on step sectioning of the SLN. CONCLUSION: Sentinel lymph node mapping in colon carcinoma cannot accurately predict nodal status.

Glutamine and alanyl-glutamine dipeptide reduce mesenteric plasma extravasation, leukocyte adhesion and tumor necrosis factor-α (TNF-α) release during experimental endotoxemia.

Glutamine (GLN) appears to be an essential nutrient during organism development and critical illness. The aim of our study was to evaluate the effects of GLN and its generic preparation alanyl-glutamine-dipeptide (DIP) on the microcirculation in endotoxemia in rats and its effects on tonus or aortal rings in vitro. Male Lewis rats (n=40) were separated in 4 groups. Group 1 (CON) served as healthy control group while the other groups received an endotoxin bolus i.v. (5 mg/kg lipopolysaccharide, LPS i.v.). In group 3 (LPS+GLN) 0.75 g/kg-1 GLN i.v. before LPS challenge was administered. In group 4 (LPS+DIP) DIP containing 0.75 g/kg GLN was given. Leukocyte-endothelial interactions and mesenteric plasma extravasation were determined at 0, 1 and 2 hours during the experiment by intravital fluorescence microscopy (IVM). Cytokine release (TNF-alpha, IL-1 beta, IL-6, IL-10) was measured by ELISA. GLN treatment reduced leukocyte adherence (-49.7% vs. LPS group, p<0.05) and plasma extravasation (-12.3% vs. LPS group, p<0.05) significantly during endotoxemia compared to untreated LPS animals. In group 4 (DIP+LPS), a decrease of leukocyte adherence (-56.0%) and mesenteric plasma extravasation (-18.8% vs. LPS group, p<0.05) was also found. TNF-alpha levels were reduced in both GLN and DIP (p<0.05). In vitro experiments demonstrated that glutamine agents could attenuate the response to contracting agents in presence of the vascular endothelium, implying nitric oxide pathway. In vivo, GLN as well as DIP pre-treatment diminish the detrimental impact of endotoxemia on the mesenteric microcirculation and the TNF-alpha release, the effects whose clinical importance should be further examined.