Is myocardial adrenergic responsiveness depressed in human septic shock?

Objective: To assess left ventricular (LV) contractile function and adrenergic responsiveness in septic patients. Methods: We used echocardiographically defined fractional area of contraction (FAC), and LV area to end-systolic arterial pressure estimates of end-systolic elastance (E'es) and its change in response to dobutamine (5 μg/kg/min) in 10 subjects in septic shock admitted to an intensive care unit of an academic medical center. Subjects were studied on admission and again at both 5 days and 8-10 days after admission. Results: Three of the 10 subjects died as a result of their acute process, while the others were discharged from hospital. Nine out of 10 subjects required intravenous vasopressor therapy on day 1, while only 1 of 9 subjects required vasopressor support at day 5. LV end-diastolic area (EDA) increased from day 1 to day 5 and days 8-10 (p < 0.05), but neither FAC nor E'es was altered by time (EDA 15.7 ± 5.8, 21.4 ± 5.1, and 19.4 ± 5.6 cm2; FAC 0.46 ± 0.19, 0.50 ± 0.20, and 0.48 ± 0.15%; E'es 21.6 ± 12.6, 23.2 ± 8.5, and 19.2 ± 6.3 mmHg/cm2, mean ± SD, for days 1, 5 and 8-10 respectively). Although dobutamine did not alter E'es on day 1 or day 5, E'es increased in all of the 5 subjects studied on days 8-10 (p < 0.05). Conclusions: Adrenergic hyporesponsiveness is present in septic shock and persists for at least 5 days into recovery, resolving by days 8-10 in survivors. © 2008 Springer-Verlag

Assessing written work by determining competence to achieve the module-specific learning outcomes.

This chapter describes lasers and other sources of coherent light that operate in a wide wavelength range. First, the general principles for the generation of coherent continuous-wave and pulsed radiation are treated including the interaction of radiation with matter, the properties of optical resonators and their modes as well as such processes as Q-switching and mode-locking. The general introduction is followed by sections on numerous types of lasers, the emphasis being on todayʼs most important sources of coherent light, in particular on solid-state lasers and several types of gas lasers. An important part of the chapter is devoted to the generation of coherent radiation by nonlinear processes with optical parametric oscillators, difference- and sum-frequency generation, and high-order harmonics. Radiation in the extended ultraviolet (EUV) and x-ray ranges can be generated by free electron lasers (FEL) and advanced x-ray sources. Ultrahigh light intensities up to 1021 W/cm2 open the door to studies of relativistic laser–matter interaction and laser particle acceleration. The chapter closes with a section on laser stabilization