Zeeshan Khan

Clonidine has proved to be a clinically useful adjunct in clinical anaesthetic practice as well as in chronic pain therapy because it has both anaesthetic and analgesic-sparing activity. The more selective alpha-2 adrenoceptor agonists, dexmedetomidine and mivazerol, may also have a role in providing haemodynamic stability in patients who are at risk of peri-operative ischaemia. The side-effects of hypotension and bradycardia have limited the routine use of alpha-2 adrenoceptor agonists. Investigations into the molecular pharmacology of alpha-2 adrenoceptors have elucidated their role in the control of wakefulness, blood pressure and antinociception. We discuss the pharmacology of alpha-2 adrenoceptors and their therapeutic role in this review. The alpha-2 adrenoceptor agonists are agonists at imidazoline receptors which are involved in central blood pressure control. Selective imidazoline agonists are now available for clinical use as antihypertensive agents and their pharmacology is discussed.

We investigated a total of 36 subjects with a mean (SD) age of 65 (13) years, during baseline conditions (supine, before any anaesthesia), and then during one of the following protocols: (1) lithotomy positioning (n = 12), (2) epidural anaesthesia (n = 12), (3) general anaesthesia in the supine position (n = 12). Lung aeration, ventilation/perfusion matching, gas exchange and functional residual capacity were measured. Lung aeration was normal during baseline assessment with almost no regions with poor aeration and no substantial dependent densities. Shunt and perfusion of poorly ventilated regions were minor. Lithotomy positioning did not reduce functional residual capacity and did not affect aeration of the lung or ventilation/perfusion matching. Epidural anaesthesia, in general, had no effect on aeration, ventilation/perfusion matching or gas exchange, regardless of whether the patient was in the supine or lithotomy position. General anaesthesia, however, caused significant increases in poorly aerated lung regions and in dependent densities (interpreted as atelectasis). In conclusion, no or little impairment of lung aeration and ventilation/perfusion matching was caused by the lithotomy position and/or epidural anaesthesia, contrary to the effects seen during general anaesthesia. However, our findings also suggest that being overweight is a factor that may cause impairment of lung aeration.

OBJECTIVES: Our goal was to describe a single-center's experience in managing acute and chronic mesenteric ischemia with endovascular therapies. BACKGROUND: Open surgical revascularization has been considered the historical gold standard treatment for mesenteric ischemia though it poses considerable morbidity and mortality risk. An aging population with increased comorbidities makes endovascular treatment a more attractive treatment option. METHODS: Consecutive subjects receiving percutaneous mesenteric interventions for acute and chronic mesenteric ischemia from 2004 to 2010 were identified retrospectively. Information on comorbidities, symptoms, screening tests, procedural outcomes, and follow up was obtained. RESULTS: Thirty-one patients received percutaneous mesenteric interventions during this period. The mean age of the population was 65.0 years with roughly equal proportions of males (48.4%) and females (51.6%). Traditional cardiovascular risk factors were highly prevalent (hypertension 45.2%, diabetes 25.8%, dyslipidemia 38.7%, nicotine use 45.2%). Procedural success was 93.5%; no periprocedural complications were reported. During a mean follow up of 13 months, 16.1% required repeat revascularization and 22.6% died. Endovascular treatment of acute mesenteric ischemia was successful (n = 8) and no patient required open surgical revascularization acutely or during follow-up. CONCLUSIONS: Endovascular treatment of mesenteric ischemia is a safe and effective therapy with acceptable long-term results. Our experience with acute mesenteric ischemia suggests that percutaneous treatment may be an effective alternative to surgical revascularization in appropriately selected patients.