Anesthesiology
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Advanced age is associated with an increased susceptibility and mortality of the acute respiratory distress syndrome. This may be due to the progressive changes in innate immune responses and intrinsic properties of the lung that occur during the process of aging. Therefore, this study assesses the association between maturation and aging and pulmonary responses to injury in animal models of lung injury. ⋯ Increasing age seems to be correlated with exaggerated pulmonary responses to injury, ultimately leading to more severe lung injury. Pulmonary inflammation seems relatively suppressed in infants/juveniles, whereas in the middle aged/elderly, the inflammatory response seems delayed but aggravated. This implies that investigators and clinicians need to use caution about extrapolating results from adolescent or youngadult animals to pediatric or elderly patients in clinical practice.
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Blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) has been used to study the effects of anesthetic agents on correlated intrinsic neural activity. Previous studies have focused primarily on intravenous agents. The authors studied the effects of sevoflurane, an inhaled anesthetic. ⋯ Sevoflurane-induced unconsciousness is associated with both globally reduced BOLD signal amplitudes and selectively reduced functional connectivity within cortical networks associated with consciousness (default mode network) and orienting to salient external stimuli (ventral attention network). Scrupulous attention to minimizing the impact of head motion artifact is critical in fMRI studies using anesthetic agents.
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Clinical Trial
Pulse Photoplethysmographic Analysis Estimates the Sympathetic Activity Directed to Heart and Vessels.
Novel pulse photoplethysmographic-derived indices have been proposed as tools to measure autonomic nervous system (ANS) modulation in anesthetized and awake patients, but nowadays their experimental validation is lacking. The authors aimed to investigate the ability of pulse photoplethysmographic amplitude (PPGA), ANS state (ANSS), and ANSS index (ANSSi) to measure changes of ANS modulation in response to sympathetic stimulation. ⋯ In controlled experimental conditions, novel pulse plethysmographic indices seem to estimate the changes of the sympathetic outflow directed to the vessels and the sympathovagal balance modulating heart rate. These indices might be useful in the future to monitor the fluctuation of sympathetic activity in anesthetized patients.
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Several pharmacokinetic models are available for dexmedetomidine, but these have been shown to underestimate plasma concentrations. Most were developed with data from patients during the postoperative phase and/or in intensive care, making them susceptible to errors due to drug interactions. The aim of this study is to improve on existing models using data from healthy volunteers. ⋯ Using target-controlled infusion in healthy volunteers, the pharmacokinetics of dexmedetomidine were best described by a three-compartment allometric model. Apart from weight, no other covariates were identified.