Anesthesia and analgesia
-
Anesthesia and analgesia · Feb 2017
Vapor Pressures of Anesthetic Agents at Temperatures Below 0°C and a Novel Anesthetic Delivery Device.
At room temperature, the vapor pressures of desflurane, isoflurane, and sevoflurane are well above the clinically useful range. We hypothesized that therapeutic concentrations of these agents could be achieved at temperatures below 0°C, but the vapor pressure-temperature relationship is unknown below 0. Second, we hypothesized that this relationship could be exploited to deliver therapeutic-range concentrations of anesthetic vapor. ⋯ We report, for the first time, the temperature-vapor pressure relationship at temperatures below 0°C for desflurane, isoflurane, and sevoflurane as well as the TMAC of these agents: the temperature at which the vapor pressure is equal to the minimum alveolar concentration. We describe the construction and limited validation of an anesthetic vaporizer prototype on the basis of this principle. We conclude that clinically relevant concentrations of volatile anesthetics may be achieved at low temperatures.
-
Anesthesia and analgesia · Feb 2017
Randomized Controlled TrialEarly Left and Right Ventricular Response to Aortic Valve Replacement.
The immediate effect of aortic valve replacement (AVR) for aortic stenosis on perioperative myocardial function is unclear. Left ventricular (LV) function may be impaired by cardioplegia-induced myocardial arrest and ischemia-reperfusion injury, especially in patients with LV hypertrophy. Alternatively, LV function may improve when afterload is reduced after AVR. The right ventricle (RV), however, experiences cardioplegic arrest without benefiting from improved loading conditions. Which of these effects on myocardial function dominate in patients undergoing AVR for aortic stenosis has not been thoroughly explored. Our primary objective is thus to characterize the effect of intraoperative events on LV function during AVR using echocardiographic measures of myocardial deformation. Second, we evaluated RV function. ⋯ LV function improved after replacement of a stenotic aortic valve demonstrated by improved longitudinal strain rate. In contrast, RV function, assessed by longitudinal strain, was reduced.
-
Anesthesia and analgesia · Feb 2017
Predicting Fluid Responsiveness in Acute Liver Failure: A Prospective Study.
The profound hemodynamic changes seen in acute liver failure (ALF) resemble the hyperdynamic state found in the later stages of septic shock. Vasopressor support frequently is required after initial volume therapy. Markers of preload dependency have not been studied in this patient group. Dynamic maneuvers such as passive leg raising or end-expiratory hold, which have shown good predictive accuracy in a general intensive care unit population, cannot be considered safe in this cohort because of the concerns of intracranial hypertension. ⋯ PPV based on pulse contour analysis predicted fluid responsiveness in ALF.
-
Anesthesia and analgesia · Feb 2017
Anesthesia for Ambulatory Pediatric Surgery in Sub-Saharan Africa: A Pilot Study in Burkina Faso.
Long surgical wait times and limited hospital capacity are common obstacles to surgical care in many countries in Sub-Saharan Africa (SSA). Introducing ambulatory surgery might contribute to a solution to these problems. The purpose of this study was to evaluate the safety and feasibility of introducing ambulatory surgery into a pediatric hospital in SSA. ⋯ No serious complications were associated with ambulatory surgery. Its introduction could possibly be a solution to improving pediatric surgical access in low-income countries.
-
Anesthesia and analgesia · Feb 2017
Observational StudyRelationship Between Preoperative Evaluation Blood Pressure and Preinduction Blood Pressure: A Cohort Study in Patients Undergoing General Anesthesia.
For outcomes research where changes in intraoperative blood pressure are a possible causative factor, it is important to determine an appropriate source for a reference value. We studied to what extent preinduction blood pressure values in the operating room differ from those obtained during preoperative evaluation outside the operating room. ⋯ The average preinduction blood pressure was higher than the preoperative blood pressure. This difference between the measurements can be explained by stress-induced effects and regression to the mean. To define an optimal reference value for research purposes or to arrive at a clinical perioperative blood pressure target, one should consider that there is important variability both within and between patients.