摘要:

Purpose of reviewThe timing and magnitude of drug onset can be influenced by factors in the chain of drug delivery from the site of administration to the site of effect. This review examines recent evidence regarding the contribution and significance of these factors.Recent findingsIt is apparent that drug formulations and mixtures can play a significant role in drug onset. An extension of this is the effect of coadministration of drugs, which can influence drug effect both by altering the physiology underlying drug delivery and by an effect at the target organ. Of the physiological variables, cardiac output and its distribution are clearly important. Cardiac output is a significant source of variability in drug response, and indeed has been successfully incorporated into pharmacokinetic models. The pattern of cardiac output distribution is also relevant. In particular, the blood flow to target organs will influence both the timing and magnitude of the effect of some anaesthetic drugs. In addition, the role of the lung in affecting drug distribution may be important for some drugs. At the site or organ of effect itself, variability in drug distribution, drug-receptor interactions, and the influence of other drugs, can all impact on the profile of drug onset.SummaryFactors in the chain of drug delivery have been demonstrated to affect the nature of drug onset, and can account for some of the observed variability in response. The significance to dosing guidelines and strategies, and to predictions of variability in response, remains to be explored.

ISSN:0952-7907    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Purpose of reviewFor more than three decades, ‘experts’ in the clinical pharmacology of neuromuscular blocking agents have advocated routine intraoperative use of peripheral nerve stimulators as monitors of neuromuscular function. This advice is far from universally honored in practice. In part, this dichotomy between ‘accepted wisdom’ and actual day-to-day practice may stem from a failure to provide the clinician with a peripheral nerve stimulator that does not require subjective evaluation of evoked responses. For 99% of anesthetists, the train-of-four fade ratio is a parameter that they read about but cannot measure. This need no longer be the case.Recent findingsSmall battery operated units are now available that are relatively inexpensive, easy to set up, and provide objective measurement of the train-of-four ratio. Although agreement between the output of these acceleromyographic and piezoelectric sensors with such ‘gold standard’ technologies as mechanomyography and electromyography is not absolute, it is probably adequate for clinical case management.SummaryIt is my hope (and I have no financial interest in any of the cited devices) that the present review will encourage further distribution of objective monitors of neuromuscular function.

ISSN:0952-7907    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Purpose of reviewClosed-loop systems are able to make decisions on their own and try to reach and maintain a preset target. As a result, they might help the anaesthesiologist in optimizing the titration of drug administration without overshooting, controlling physiological functions and guiding monitoring variables. Thanks to the development of fast computer technology and more reliable pharmacological effect measures, the study of automation in anaesthesia has regained popularity.Recent findingsThis short review focuses on the most recently developed and tested feed-back systems in anaesthesia. Various new approaches for controlling the administration of intravenous and inhaled hypnotic-anaesthetic drugs have been published recently. For analgesics, a framework for further research has been presented in the literature. For other drugs, such as muscle relaxants and haemodynamics, a short review can be found.SummaryUntil now, most of these systems are still under development. The challenge is now to establish fully the safety, efficacy, reliability and utility of closed-loop anaesthesia for its adoption into the clinical setting. Besides the optimization of controlled variables and control models, these systems have to be tested in extreme circumstances.

ISSN:0952-7907    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Purpose of reviewAnesthetics influence a wide variety of transmitter- and voltage-gated ion channels in the mammalian central nervous system. At the molecular level, the γ-aminobutyric acid (GABA) subtype A receptor has emerged as a primary therapeutic target. This review highlights recent advances in our understanding of how anesthetics modify GABAAreceptor function.Recent findingsAnesthetics bind to discrete selective binding sites on GABAAreceptors - a discovery that challenges lipid-based theories of anesthesia. Not all GABAAreceptors are equally sensitive to anesthetics because positive allosteric modulation is critically dependent on receptor subunit composition. Moreover, GABAAreceptors located in extrasynaptic regions of hippocampal neurons display a greater sensitivity to propofol and benzodiazepines than do receptors located in subsynaptic regions. Enhancement in GABAergic inhibition may not account for all of the behavioral end-points associated with the anesthetic state. In particular, the immobilizing properties of anesthetics may not be solely mediated by GABAAreceptors. Finally, synthetic neurosteroids are being developed as improved general anesthetics.SummaryDetailed insights into anesthetic-GABAAreceptor interactions have resulted in intense efforts to develop safer drugs that selectively target subtypes of GABAAreceptors.

ISSN:0952-7907    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Purpose of reviewThe controversy over pre-emptive analgesia continues unabated, with studies both supporting and refuting its efficacy. The timing of an analgesic intervention and presence of a placebo control may have significant impact on the interpretation of results and may have led to the premature conclusion that pre-emptive analgesia is of limited clinical utility. A review of the recent literature using strict definitions of pre-emptive and preventive analgesia is required in order to clarify the broader issue of the benefits of perioperative analgesia.Recent findingsA total of 27 studies, published from April 2001 to April 2002, were found to evaluate pre-emptive (n= 12) or preventive analgesia (n= 15). Evidence for a benefit of preventive analgesia was strong, with 60% of studies finding reduced pain or analgesic consumption beyond the clinical duration of action of the analgesic intervention. Evidence for a benefit of pre-emptive analgesia was equivocal, with 41.7% of studies demonstrating that preincisional treatment reduces pain or analgesic consumption to a greater extent than does postincisional treatment.SummaryStudies that used a preventive design had a greater likelihood of finding a beneficial effect. The application of preventive perioperative analgesia (not necessarily preincisional) is associated with a significant reduction in pain beyond the clinical duration of action of the analgesic agent, in particular for theN-methyl-D-aspartate antagonists. The classical definition of pre-emptive analgesia should be abandoned in favor of preventive analgesia. This will broaden the scope of inquiry from a narrow focus on preincisional versus postincisional interventions to one that aims to minimize postoperative pain and analgesic requirements by reducing peripheral and central sensitization arising from noxious preoperative, intraoperative and postoperative inputs.

ISSN:0952-7907    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Purpose of reviewThe increasing use of magnetic resonance imaging as a diagnostic modality has led to increased demand for sedation and monitoring during the procedure. This review is to acquaint the reader with the most recent developments in magnetic resonance imaging diagnostics and to describe the evolving techniques and strategies for patient management.Recent findingsMany centers are meeting the challenges of increasing demand by streamlining their sedation/anesthetic protocols to achieve greater efficiency. Some have enlisted the help of nursing staff who are trained to provide sedation for certain patients. Continued experience in magnetic resonance imaging anesthesia has led to a better understanding of patient needs and decreased the number of failed procedures. The scope of magnetic resonance imaging diagnostics has expanded to include urology, otolaryngology, and neonatal evaluation. Although infants and children constitute the majority of patients, many adults also require anesthesia for magnetic resonance imaging and present their own challenges.SummaryAnesthesia and sedation during magnetic resonance imaging have a unique set of constraints. However, most of the standards of modern, safe anesthetic care can be met in this environment. The growing experience at many hospitals has demonstrated that a wide range of patients can receive safe care during magnetic resonance imaging.

ISSN:0952-7907    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Purpose of reviewThe capabilities of interventional radiology are developing faster than perhaps any other branch of medicine. Coupled with and fuelled by parallel advances in computer technology, medical physics and developments in endovascular catheter technology, interventional radiologists are innovating not only replacements for open surgeries, but entirely new therapies as well. This has, however, provided a range of new potential complications for the patient and, in contrast to other areas, presents risks for the anesthesiologist as well.Recent findingsThe techniques involved in interventional radiology have found applications throughout not only medicine but surgery in particular. Here there has been amedicalization of surgical procedures. CT scanning has evolved to the extent that it is now possible to utilize multislice CT scanners, ones with multiple, flat panel digital detectors, to provide real time CT fluoroscopy. Similarly this technology has facilitated the construction of hybrid iMR/X-ray systems, thus enabling dual modality imaging without moving the patient. Another facet of the new breed of iMR systems is their integration in real time with computerized, frameless stereotactic navigation systems. This has enabled the radiological image to keep pace with the changes in anatomy consequent to anesthetic and surgical manipulations.SummaryIn the light of these new developments in interventional radiology there is much research to be done. Further developments in imaging and computer processing technology will doubtless make possible the real time integration of anatomical image with metabolic state and functional anatomy. The impact of the hazards of these new techniques on the safety of anesthesia has, however, been the subject of virtually no research. A particularly needy area will be the ergonomics of the delivery of anesthesia care in these new environments.

ISSN:0952-7907    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Purpose of reviewThe purpose of the present review is to provide the reader with a synopsis of the recent literature on sedation of children by non-anesthesiologists.Recent findingsHealth care centers are experiencing an increasing demand for sedation of pediatric patients. Whether provided by physician anesthesiologists, nurse anesthetists, or appropriately credentialed non-anesthesia clinicians, this increase is a reflection of new advances in the area of diagnostic imaging, better pharmacologic agents, and a heightened awareness of the psychologic needs of children. By definition anesthesiologists are the experts when it comes to providing sedation to patients. For pediatric patients, pediatric anesthesiologists provide the most appropriate specialization. However, because of insufficient manpower, anesthesiologists cannot adequately meet the increasing workload of providing sedation for each child in need.SummaryIn some circumstances the incidence of adverse events when sedation is provided by non-anesthesiologist can be high. Predicators of adverse outcome have been identified. Given strict adherence to sedation guidelines and appropriate credentialing of the sedation provider, non-anesthesiologists can safely provide sedation for children.

ISSN:0952-7907    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The choice of airway device for resuscitation depends on the skill of the user, the equipment available, the conscious state of the patient, the location of the patient and the probable cause of the cardiorespiratory arrest. Extraglottic airway devices are recommended by the European and American Resuscitation Councils for use when intubation skills are lacking. In this review, we discuss recent research relevant to the use of extraglottic airway devices in resuscitation.

ISSN:0952-7907    

出版商:OVID    

年代:2002

数据来源: OVID

ISSN:0952-7907    

出版商:OVID    

年代:2002

数据来源: OVID