The TEG® vs the ROTEM® thromboelastography/thromboelastometry systems

We have evaluated the TEG^® thromboelastograph and the ROTEM^® thromboelastometer, two point-of-care devices that measure blood coagulation. During a one-week period, seven consultant anaesthetists, one consultant haematologist, one associate specialist anaesthetist and two senior trainee anaesthetists were trained by the manufacturers and set up, calibrated and used both systems, after which their views were obtained and specific technical/support information was sought from the manufacturers using a questionnaire. Although the devices shared common features, they differed in complexity and aspects of ease of use, and in their purchase and running costs.     

STARR with Contour® Transtar™: prospective multicentre European study

Objective  The stapled transanal rectal resection (STARR) in patients with defecation disorders is limited by the shape and capacity of the circular stapler. A new device has been recently developed, the Contour^® Transtar^™ stapler, in order to improve the safety and effectiveness of the STARR technique. The study has been designed to confirm this declaration.
Method  From January to June 2007 a prospective European multicentre study of consecutive patients with defecation disorder caused by internal rectal prolapse underwent the new STARR technique. The assessment of perioperative morbidity and functional outcome after 6 weeks, 3 and 12 months was documented by different scores.
Results  In all 75 patients, median age 64, the Transtar procedure was performed with 9% intraoperative difficulties, 7% postoperative complications and no mortality. The mean reduction of the ODS score was −15.6 (95%−CI: −17.3 to −13.8, P  < 0.0001), mean reduction of SSS was −12.6 (95%−CI: −14.2 to −11.2; P  < 0.0001). 41% stated improvement of their continence status by CCF score, only 4 patients (5%) had deterioration.
Conclusion  The Transtar procedure is technically demanding, with good functional results similar to the conventional STARR.     

A new supraglottic airway device: LMA-Supreme™, comparison with LMA-Proseal™

Background and objective: The LMA‐Supreme^? (S‐LMA^?) is a new supraglottic airway device that presents combined features of flexibility, curved structure and single use and a different cuff structure. The purpose of this study was to compare the oropharyngeal leak pressures (OLP) of LMA‐Proseal^? (P‐LMA^?) and S‐LMA^?. Methods: Sixty adult patients were prospectively and randomly allocated to undergo insertion of P‐LMA^? (n=30) or S‐LMA^? (n=30). The cuffs were inflated until the intracuff pressure (ICP) reached 60 cm H₂O. Orogastric leak pressures, insertion times, first attempt success rates, fiberoptical assessment of position, cuff pressures, orogastric tube (OGT) placement and OGT insertion times were compared. Unblinded observers collected intraoperative data and blinded observers collected post‐operative data. Results: The first insertion attempts and time taken to provide an effective airway were similar between the groups. Two patients (P‐LMA^?, n=1; S‐LMA^?, n=1) were intubated due to excessive oropharyngeal leak and in one patient (P‐LMA^?, n=1) due to failed OGT placement. OLPs were similar (P‐LMA^?; 26.9±6.6 S‐LMA^?; 26.1±5.2). ICP increased significantly in the P‐LMA^? at the 30 and 60 min during anesthesia (P‐LMA^?; 80.1±12.8, 92.9±14.4, S‐LMA^?; 68.3±10.9, 73.7±15.6). OGT placement was successful in all patients in the S‐LMA^?, but failed in five patients in the P‐LMA^? (P=0.02). Fiberoptically determined anatomic position was better with the P‐LMA^? (P=0.03). Conclusion: Our findings suggest that S‐LMA^? had leak pressures similar to the P‐LMA^?, and this new airway device proved to be successful during both spontaneous and positive pressure ventilation.     

Air emboli with Haemaccel®

We report two cases of venous air embolism which occurred in association with infusion of Haemaccel(R) using a pressure bag. As a result of these incidents, we performed a study that showed that up to 45 ml of air can be infused into a patient from a pressurised Haemaccel(R) plastic bottle using a standard administration set. We also demonstrated that the volume of air infused was influenced by the type and size of the pressure bag and the warming of the Haemaccel(R) plastic container.     

Comparison of the Glidescope® and Airtraq® optical laryngoscopes in patients undergoing direct microlaryngoscopy

Optical laryngoscopes have been developed to facilitate difficult airway management. The Airtraq^® is a single-use device and the GlideScope^® is reusable. In this study, the Airtraq and the Glidescope were compared in 60 ASA I-III patients with tumours of the upper airway undergoing direct endoscopic microlaryngoscopy. Patients were randomly assigned to the Airtraq or the Glidescope group and the Cormack and Lehane grade was assessed by Macintosh laryngoscopy prior to tracheal intubation. There were no differences in tracheal intubation success rates or duration of intubation attempts between both devices. The Cormack and Lehane grade was improved in 77% and 82% of cases in the Airtraq and Glidescope group, respectively. Blood traces on the device and traumatic pharyngeal lesions were found more frequently in the Airtraq group. The Airtraq and Glidescope laryngoscopes are valuable tools for the management of patients with potentially difficult airways with the Glidescope appearing to be less traumatic.     

Evaluation of the HemoCue® for measuring intra-operative haemoglobin concentrations: a comparison with the Coulter Max-M®

We compared haemoglobin concentration values obtained using a portable haemoglobinometer, the HemoCue, in the operating theatre with the results obtained by the Coulter Max-M in the laboratory. Haemoglobin concentrations were measured on 52 arterial blood samples obtained from 13 patients during aortic surgery, in theatre with the HemoCue and again by the Coulter Max-M. Twenty routine samples from the laboratory were also analysed by both methods. There was no significant difference between results, with a mean of 10.94 gdl⁻¹ and 10.90 gdl⁻¹ for the HemoCue and Coulter, respectively (p = 0.12, t  = −1.99, df  = 70). The limits of agreement of the two methods (mean difference ± 2 SD) were −0.37 and +0.45 gdl⁻¹. The coefficients of repeatability of the 20 samples analysed in duplicate on each device were 0.26 gdl⁻¹ and 0.33 gdl⁻¹, respectively. The coefficients of variance were 0.74% (HemoCue) and 0.93% (Coulter). With adequate training and monitoring, the HemoCue provides comparable haemoglobin results for near-patient testing in theatre.     

T cell receptor beta chain (TCR-Vβ) repertoire of circulating CD4+ CD25−, CD4+ CD25low and CD4+ CD25high T cells in patients with long-term renal allograft survival

The mechanisms underlying maintenance of renal allografts in humans under minimal or conventional immunosuppression are poorly understood. There is evidence that CD4⁺ CD25⁺ regulatory T cells and clonal deletion, among other mechanisms of tolerance, could play a key role in clinical allograft survival. Twenty‐four TCR‐Vβ families were assessed in CD4⁺ CD25^?, CD4⁺ CD25^low and CD4⁺ CD25^high T cells from patients with long‐term renal allograft survival (LTS), patients exhibiting chronic rejection (ChrRx), patients on dialysis (Dial) and healthy controls (HC) by flow cytometry. LTS patients presented a higher variability in their TCR‐Vβ repertoire, such decreased percentage of Vβ2⁺, Vβ8a⁺ and Vβ13⁺ in CD4⁺ CD25^low and ^high compared with CD4⁺ CD25^? subset and increased Vβ4 and Vβ7 families in CD4⁺ CD25^high T cells exclusively. Additionally, LTS patients, particularly those that were not receiving calcineurin inhibitors (CNI), had increased percentages of CD4⁺ CD25^high T cells when compared with Dial (P < 0.05) and ChrRx (P < 0.05) patients. Our results suggest that a differential expression of particular TCR‐Vβ families and high levels of circulating CD4⁺ CD25^high T cells in long‐term surviving renal transplant patients could contribute to an active and specific state of immunologic suppression. However, the increase in this T cell subset with regulatory phenotype can be affected by CNI.     

CD4+ CD25+ CD62+ T-Regulatory Cell Subset Has Optimal Suppressive and Proliferative Potential

CD4+ CD25+ regulatory T cells (Treg) are potent suppressors, and play important roles in autoimmunity and transplantation. Recent reports suggest that CD4+ CD25+ Treg are not a homogeneous cell population, but the differences in phenotype, function, and mechanisms among different subsets are unknown. Here, we demonstrate CD4+ CD25+ Treg cells can be divided into subsets according to cell-surface expression of CD62L. While both subsets express foxp3 and are anergic, the CD62L+ population is more potent on a per cell basis, and proliferates and maintains suppressive function far better than the CD62L- population and unseparated CD4+ CD25+ Treg. The CD62L+ population preferentially migrates to CCL19, MCP-1 and FTY720. Both CD62L+ and CD62L- subsets prevent the development of autoimmune gastritis and colitis induced by CD4+ CD25-CD45RBhigh cells in severe combined immunodeficiency (SCID) mice. Overall, these results suggest CD4+ CD25+ Treg are not a homogenous cell population, but can be divided into at least two subsets according to CD62L expression. The CD62L+ subset is a more potent suppressor than the CD62L- population or unfractionated CD4+ CD25+ Treg cells, can be expanded far more easily in culture, and is more responsive to chemokine-driven migration to secondary lymphoid organs. These properties may have significant implications for the clinical manipulation of the CD4+ CD25+ CD62L+ cells.     

Differential Roles of CD8+ and CD8− T Lymphocytes in Corneal Allograft Rejection in ''High-Risk'' Hosts

We examined the role of perforin and FasL in corneal allograft rejection mediated by CD8+ and CD8 T cells. BALB/c corneas were transplanted orthotopically into vascularized, 'high-risk' graft beds in C57BL/6 mice, perforin knockout mice and FasL-defective gld/gld mice. CD8+ and CD8 T cells were collected following graft rejection and adoptively transferred to SCID mice, which were then challenged with BALB/c corneal allografts. In every case, CD8 T cells could mediate graft rejection when adoptively transferred to SCID mice that received BALB/c corneal allografts. Although CD8+ T cells also mediated graft rejection, the tempo was slower. Moreover, CD8+ T cells collected FasL-defective donors that had rejected corneal allografts, mediated corneal allograft rejection in only 50% of the SCID mice that received the adoptively transferred cells. In some cases, CD8+ T-cell-mediated rejection occurred in the absence of delayed-type hypersensitivity and cytotoxic T-lymphocyte activity, but was associated with CD8+ T-cell-mediated apoptosis of BALB/c corneal cells in vitro. The results demonstrate the redundancy in immune mechanisms of corneal allograft rejection. Either CD8+ or CD8 T cells can produce corneal allograft rejection, however functional FasL is necessary for optimal rejection, even in a high-risk setting.     

An assessment of the efficiency of the Glostavent® ventilator

In parts of the world where supplies of oxygen and electricity are erratic, ventilating patients' lungs can be problematic. Should the electricity supply fail, gas driven ventilators have an advantage as they can continue functioning. However, many are extravagant in their requirement for the driving gas. The Glostavent^® ventilator was designed to minimise these requirements. We measured the duration of ventilation achieved by the Glostavent ventilator using an E-size oxygen cylinder at a range of minute volumes, and the inspired oxygen concentration achieved by recycling the driving gas. The period of mechanical ventilation from a single E-size cylinder ranged from 11 h 8 min (SD 4 min) with a minute volume of 7 l.min⁻¹ to 18 h 15 min (SD 7 min) with a minute volume of 3 l.min⁻¹. The mean fractional inspired oxygen concentration achieved by recycling the driving gas without further inspired oxygen supplementation was 0.33. We conclude that the Glostavent ventilator performs as efficiently and cost effectively as predicted.