Anesthesia and analgesia
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Anesthesia and analgesia · May 2009
Randomized Controlled Trial Comparative StudyContinuous interscalene brachial plexus block via an ultrasound-guided posterior approach: a randomized, triple-masked, placebo-controlled study.
The posterior approach for placing continuous interscalene catheters has not been studied in a controlled investigation. In this randomized, triple-masked, placebo-controlled study, we tested the hypothesis that an ultrasound-guided continuous posterior interscalene block provides superior postoperative analgesia compared to a single-injection ropivacaine interscalene block after moderately painful shoulder surgery. ⋯ Compared to a single-injection interscalene block, a 2-day continuous posterior interscalene block provides greater pain relief, minimizes supplemental opioid requirements, greatly improves sleep quality, and increases patient satisfaction after moderate-to-severe painful outpatient shoulder surgery.
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Anesthesia and analgesia · May 2009
Randomized Controlled Trial Comparative StudySurface anatomy as a guide to vertebral level for thoracic epidural placement.
Precise placement of thoracic epidural catheters is required to optimize postoperative analgesia and minimize adverse effects. Previous research demonstrated that anesthesiologists are inaccurate when using surface anatomy to locate vertebral levels. In this study, we compared the accuracy of two different landmarks to identify the seventh thoracic (T7) spinous process. ⋯ For patients with a BMI <25, the T7 spinous process can be reliably identified to within one interspace in 78% of patients using the C7 (vertebra prominens) surface landmark. Neither the vertebra prominens nor the tip of scapula is a reliable landmark to identify T7 in patients with a BMI >or=25.
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Anesthesia and analgesia · May 2009
The feasibility of measuring renal blood flow using transesophageal echocardiography in patients undergoing cardiac surgery.
There is no reliable method to monitor renal blood flow intraoperatively. In this study, we evaluated the feasibility and reproducibility of left renal blood flow measurements using transesophageal echocardiography during cardiac surgery. ⋯ In patients undergoing cardiac surgery, it was feasible in 60% of the subjects to measure left renal blood flow using intraoperative transesophageal echocardiography. The interobserver and intraobserver reproducibility of renal blood flow measurements was good to excellent.
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Perioperative bleeding is a major challenge particularly because of increasing clinical use of potent antithrombotic drugs. Understanding current concepts of coagulation is important in determining the preoperative bleeding risk of patients, and in managing hemostatic therapy perioperatively. The serine protease thrombin plays pivotal roles in the activation of additional serine protease zymogens (inactive enzymatic precursors), cofactors, and cell-surface receptors. ⋯ However, a limitation of current treatment is that conventional clotting tests do not reflect the entire physiological processes of coagulation making optimal pharmacologic therapy difficult. Understanding the in vivo regulatory mechanisms and pharmacologic modulation of thrombin generation may help control bleeding without potentially increasing prothrombotic risks. In this review, we focus on the regulatory mechanisms of hemostasis and thrombin generation using multiple, simplified models of coagulation.