British journal of anaesthesia
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Gamma (30-80 Hz) and high-gamma (80-200 Hz) thalamocortical EEG rhythms are involved in conscious processes and are attenuated by isoflurane and propofol. To explore the hypothesis that this attenuation is a correlate of anaesthetic action, we characterized the effect dexmedetomidine, a selective adrenergic α-2 agonist with lesser hypnotic potency, on these rhythms. ⋯ Dexmedetomidine attenuates high-frequency thalamocortical rhythms, but to a lesser degree than isoflurane and propofol. The main differences between dexmedetomidine and the other anaesthetics involved thalamic rhythms, further substantiating the link between impaired thalamic function and anaesthesia. Increased delta coherence likely reflects cyclic hyperpolarization of thalamocortical networks and may be a marker for loss of consciousness.
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Historical Article
Growing the next generation of anaesthesia research leaders.
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Observational Study
Is postspinal hypotension a sign of impaired cardiac performance in the elderly? An observational mechanistic study.
We have previously reported that stroke volume is reduced in a majority of elderly patients undergoing surgical repair of hip fracture before and after intrathecal injection of anaesthetic. We aimed to investigate these observations further in a prospective study of elderly patients undergoing elective hip or knee arthroplasty under spinal anaesthesia. ⋯ A decrease in cardiac output from baseline before spinal anaesthesia and an inability to increase it after induction may be important features of postspinal hypotension in elderly patients.
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There is a consistent relationship between physical activity, physical fitness, and health across almost all clinical contexts, including the perioperative setting. Physiological measurements obtained during physical exercise may be used to infer the risk of adverse outcome after major surgery. In particular, data obtained from perioperative cardiopulmonary exercise testing have an expanding role in perioperative care. ⋯ Furthermore, studies evaluating exercise interventions aimed at increasing preoperative exercise capacity have established that training improves physical fitness. However, to date, this literature is largely composed of feasibility and pilot studies with small sample sizes, which are in general underpowered to assess clinical outcomes. Adequately powered prospective multicentre studies are needed to characterize the most effective means of improving patient fitness before surgery and to evaluate the impact of such improvements on surgical and disease-specific (e.g. cancer) outcomes.