Teaching ultrasound-guided regional anesthesia remotely: a feasibility study.

BACKGROUND: Ultrasound-guided regional anesthesia (UGRA) requires acquisition of new skills. Learning requires one-on-one teaching, and can be limited by time and mentor availability. We investigate whether the skills required for UGRA can be developed and subsequently assessed remotely using a novel online teaching platform. This platform was developed at the University of Toronto to teach laparoscopic surgery remotely and has been termed Telesimulation. METHODS: Anesthesia Site Chiefs at 10 hospitals across Ontario were sent a letter inviting their anesthesia teams to participate in an UGRA remote training program. Four to five anesthetists from each site were recruited from the first four hospitals expressing interest. Simulation models and ultrasound machines were set up at each location and connected via Skype(™) and web cameras with the Telesimulation center at our hospital. Training consisted of four online sessions and one offline lecture in order to teach an ultrasound-guided supraclavicular block. Participants were evaluated before and after training by on-site and off-site assessors using a validated Checklist and Global Rating Scale (GRS). RESULTS: Nineteen staff anesthetists were recruited. Post-training scores were significantly higher across both assessment tools, on-site (P < 0.001) and off-site training locations (P = 0.003). The inter-rater reliability between on-site and remote training site ratings was good for the Checklist (ICC = 0.672, 95% CI: 0.369-0.830) and excellent for the GRS (ICC = 0.847, 95% CI: 0.706-0.921). CONCLUSION: This study demonstrates that UGRA can be taught remotely. Future research will focus on comparing this method to on-site teaching and its application in resource-restricted countries.

Management of refractory venous thrombosis associated with malignancy using a supra-therapeutic enoxaparin regimen.

For many years, it has been recognised that venous thrombo-embolism (VTE) represents a common complication of malignancy. Moreover, VTE in the form of pulmonary embolism (PE) is life-threatening, and constitutes the second leading cause of death in patients with cancer. Consequently, overall survival is significantly reduced in cancer patients who develop thrombosis. In addition, treatment of VTE with anticoagulation is often difficult to manage in the context of cancer. Studies have shown that the risk of recurrent VTE, and the risk of major bleeding are both increased significantly in cancer patients on therapeutic anticoagulant therapy. In this case report, we describe a patient with metastatic carcinoma of the cervix, who developed recurrent thrombotic complications despite being maintained on standard therapeutic doses of both warfarin, and subsequently low molecular weight heparin. However, her refractory VTE was successfully managed using a supra-therapeutic dose low-molecular-weight-heparin (LMWH) regimen, together with close monitoring of plasma anti-Xa levels.

Prevention and management of venous thromboembolism in people with cancer: a review of the evidence.

Venous thromboembolism (VTE) constitutes an important health problem in developed countries. Owing to their underlying malignancies, people with cancer are at particularly high risk of VTE. The level of this risk is influenced by several factors, including type of cancer and the presence or absence of metastases. However, different types of oncology treatment can also further increase the thrombotic risk. Consequently, primary and secondary thromboprophylaxis in people with cancer should be considered as part of any integrated oncology treatment. Moreover, recent exciting studies have suggested that low molecular weight heparins (LMWH) may also influence overall survival in people with cancer. Clearly, these findings raise the likelihood that the use of LMWH in oncology practice may increase significantly in the near future. However, it is important to appreciate that the use of thromboprophylaxis in people with cancer is complicated by a number of specific problems. In this overview, we have systematically addressed the difficult clinical issues that are involved in the selection of appropriate primary and secondary thromboprophylaxis for people with cancer.

Primary thromboprophylaxis for cancer patients with central venous catheters--a reappraisal of the evidence.

Venous thromboembolism (VTE) is responsible for an estimated 25 000 deaths per annum in UK hospital practice. It is well established that many of these deaths could be prevented through the use of appropriate thromboprophylaxis. This issue is of particular relevance in oncology practice, where the risks of VTE and bleeding are both significantly higher than those observed in general medical patients. Cancer patients with in-dwelling central venous catheters (CVCs) are at particularly high risk of developing thrombotic complications. However, the literature has produced conflicting conclusions regarding the efficacy of using routine primary thromboprophylaxis in these patients. Indeed such is the level of confusion around this topic, that the most recent version of the American College of Chest Physicians (ACCP) guidelines published in 2004 actually reversed their previous recommendation (published in 2001). Nevertheless, minidose warfarin continues to be routinely used in many oncology centres in the UK. In this article, we have performed a systematic review of the published literature regarding the efficacy and the risks, associated with using thromboprophylaxis (either minidose warfarin or low-dose LMWH) in cancer patients with CVC. On the basis of this evidence, we conclude that there is no proven role for using such thromboprophylaxis. However, asymptomatic CVC-related venous thrombosis remains common, and further more highly powered studies of better design are needed in order to define whether specific subgroups of cancer patients might benefit from receiving thromboprophylaxis.

Digital analysis of myocardial contrast echocardiography: a clinical study using an air-filled agent in normal subjects.

The purpose of the present study was to determine whether direct digital image analysis would allow improved detection of myocardial contrast. Eighteen normal subjects were recruited and separated into two groups. In group 1, the time-brightness curves of the left ventricular cavity and three myocardial perfusion beds were formed from digitized video tape, with output power and imaging time as secondary variables. In group 2, curves constructed from direct polar digital data were compared, with fundamental and second harmonic image formation as variables. In group 1 subjects, using fundamental imaging, the area under the curve in the left ventricular cavity increased slightly with intermittent imaging. No consistent myocardial opacification was identified. In group 2 subjects, using intermittent imaging, the area under the myocardial curve and peak intensity increased with high output, second harmonic imaging in the left anterior descending and right coronary artery regions. Intermittent, second harmonic imaging and digital processing can demonstrate myocardial contrast even with an air-filled agent.

Long-term hemodynamic responses to vasodilator therapy in patients with severe left ventricular dysfunction.

Maximal oral vasodilator therapy resulted in long-term reduction of initially elevated pulmonary vascular resistance in 10 of 13 patients with severe heart failure who tolerated inotrope-supported uptitration of afterload reduction. Eleven patients were unable to tolerate vasodilator therapy and required inotropic support for successful cardiac transplantation.

Evidence for a relation between inspired gas mixture and the left ventricular contrast achieved with Albunex in a canine model.

BACKGROUND: In a previous experiment, a marked reduction in the right- and left-sided contrast effect of Albunex was noted in an intubated animal spontaneously breathing isoflurane in 100% oxygen. The theory suggests that the time course of echogenicity of microbubbles in liquid is dependent on the pressure and the gradients of dissolved gases. The present set of experiments tested whether the loss of contrast occurs at commonly used therapeutic concentrations of inspired oxygen. HYPOTHESIS: This research tested the hypothesis that the left ventricular (LV) contrast effect achieved with intravenous injection of the ultrasound contrast agent Albunex is related to the inspired oxygen content. METHODS: Intubated dogs were maintained in a spontaneously respiring anesthetic state on isoflurane and mixtures of oxygen (12-50%) in nitrogen. FIO2 was held steady for 15 min prior to injection of 0.08 ml/kg of Albunex. The contrast effects were recorded from a transthoracic short-axis view. Left and right ventricular brightness curves were generated from digitized sequences of end-diastolic frames. The minimum and maximum brightness and area under the time-brightness curves were determined. RESULTS: The LV maximum brightness and area under the curve showed significant negative correlations (p = < 0.004) with the FIO2, while the minimum brightness showed a significant positive correlation (p = < 0.002). No significant correlations were found for the right ventricular brightness parameters. CONCLUSIONS: These findings show an important relationship between the FIO2 and loss of the contrast effect of Albunex. This loss occurs at oxygen concentrations in the therapeutic range, but could be overcome by increasing the dose of Albunex. The mechanism is likely related to an outward nitrogen gradient causing a loss of echogenicity. The clinical implication is that patients on supplemental oxygen may require higher doses of Albunex to achieve optimal opacification.

Tension pneumothorax complicating pulmonary hydatid disease in childhood.

The case of a 3-year-old girl with bilateral pulmonary hydatid disease presenting as a tension pneumothorax is described. This is a rare but serious complication of hydatid disease in the pediatric age group which may arise as a result of rapid growth of the cyst in the lung and low resistance to its expansion. Prompt relief of the pneumothorax with intercostal drainage is advocated, followed by early surgical removal of any suspected cyst to avoid further complication.

Successful orthotopic heart-lung transplantation in the baboon after five hours of cold ischemia with cardioplegia and Collins' solution.

En bloc transplantation of the heart and lungs was performed in 15 chacma baboons; the donor organs were stored between 4 and 6 hours before transplantation. The hearts were perfused in the donor animals with 15 ml/kg Wicomb's cardioplegic solution at 4 degrees C, the lungs with either 20 ml/kg 4 degrees C Collins' solution with an added 2.5% dextrose and 12 mEq magnesium sulfate (Collins' solution, group 1, n = 8), Collins' solution plus superoxide dismutase (40,000 U/L superoxide dismutase, group 2, n = 4), or Collins' solution plus superoxide dismutase plus peroxidase (5000 U/L peroxidase plus mannitol, group 3, n = 3). The pulmonary artery perfusion pressure was not allowed to exceed 50 cm water; the lungs were maintained at 30% to 50% inflation, and external cooling was applied. After explantation the thoracic organs were stored in 0.9% saline solution at 4 degrees C. In groups 1 (Collins' solution) and 2 (Collins' plus superoxide dismutase) all surviving baboons revealed normal blood gas values and normal light and electron microscopic histology at 24 hours. Three animals had further biopsies at intervals between 1 and 9 days, at which time the histology of the lungs proved normal and well preserved. All three baboons in group 3 (Collins' plus superoxide dismutase plus peroxidase) had grossly abnormal blood gas values from the time of operation, and all died within 9 hours; light microscopy of the lungs showed early lung infarctlike lesions and in one case pulmonary edema. These preclinical findings proved that storage of the lungs in Collins' solution with or without superoxide dismutase is possible for up to 5 hours; the addition of peroxidase had a detrimental effect.