Anesthesiology
-
Surgically induced ischemia and reperfusion is frequently accompanied by local and remote organ injury. It was hypothesized that this procedure may produce injurious oxidants such as hydrogen peroxide (H2O2), which, if unscavenged, will generate the highly toxic hydroxyl radical (.OH). Accordingly, it was proposed that tourniquet-induced exsanguination for limb surgery may be a useful ischemia-reperfusion model to investigate the presence of oxidants, particularly H2O2. ⋯ These studies suggest that tourniquet-induced exsanguination for limb surgery is a significant source for toxic oxygen production in the form of H2O2 and that xanthine oxidase is probably the H2O2-generating enzyme that is formed during the ischemia-reperfusion event. In contrast to the reperfused leg, the absence of H2O2 in arm blood demonstrated a balanced oxidant scavenging in the systemic circulation, despite the persistent increase in systemic xanthine oxidase activity.
-
Animal studies show that airway receptors responsible for eliciting respiratory protective reflexes are not uniformly distributed in the airways. Based on this information, it is possible that the protective reflex responses to airway irritation in humans may vary, depending on the site of stimulation. The purpose of this study is to examine whether the protective reflex responses evoked from the larynx are different from those evoked from the lower airways and to see how change in depth of anesthesia modifies the protective reflex responses evoked from individual sites. ⋯ The respiratory reflex responses evoked by injection of water vary, depending on the site of stimulation. The incidence of various reflex responses was not affected by the changing depth of anesthesia. The sensitivity to airway irritation seems to be greater at the larynx and trachea than at the more peripheral airways.
-
Comparative Study
Effects of ventilation on hemodynamics and myocardial blood flow during active compression-decompression resuscitation in pigs.
Active compression-decompression (ACD) improves hemodynamics and vital organ blood flow during cardiopulmonary resuscitation. The effects of intermittent positive pressure ventilation (IPPV) on ACD have not been studied. This study was designed to compare the effects of ACD with and without IPPV on gas exchange, hemodynamics, and myocardial blood flow. ⋯ Gas exchange was critically impaired during the late phase of ACD. Compared with ACD-IPPV, myocardial blood flow was less preserved with ACD and was too low to achieve restoration of spontaneous circulation.
-
Review Comparative Study
Measuring the performance of anesthetic depth indicators.
An appropriate measure of performance is needed to identify anesthetic depth indicators that are promising for use in clinical monitoring. To avoid misleading results, the measure must take into account both desired indicator performance and the nature of available performance data. Ideally, anesthetic depth indicator value should correlate perfectly with anesthetic depth along a lighter-deeper anesthesia continuum. Experimentally, however, a candidate anesthetic depth indicator is judged against a "gold standard" indicator that provides only quantal observations of anesthetic depth. The standard anesthetic depth indicator is the patient's response to a specified stimulus. The resulting observed anesthetic depth scale may consist only of patient "response" versus "no response," or it may have multiple levels. The measurement scales for both the candidate anesthetic depth indicator and observed anesthetic depth are no more than ordinal; that is, only the relative rankings of values on these scales are meaningful. ⋯ Prediction probability PK is an appropriate measure for evaluating and comparing the performance of anesthetic depth indicators.
-
Randomized Controlled Trial Comparative Study Clinical Trial
Prospective examination of epidural catheter insertion.
Although it is generally accepted that inserting epidural catheters 3-4 cm into the epidural space minimizes complications, no prospective randomized examination of epidural catheter insertion length has been published. ⋯ Epidural catheters should be inserted either 2 cm when rapid labor is anticipated or 6 cm when prolonged labor or cesarean delivery is likely. Additionally, epidural catheters that result in intravenous cannulation or unilateral sensory analgesia can be manipulated effectively to provide analgesia for labor and delivery.