Anesthesia and analgesia
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Anesthesia and analgesia · Nov 2016
Multicenter Study Observational StudyMetabolic Acidosis Assessment in High-Risk Surgeries: Prognostic Importance.
Metabolic acidosis frequently is present in surgical patients; however, different types of metabolic acidosis (hyperlactatemia, hyperchloremia, and others) may have different relationships to perioperative outcomes. We hypothesized that in postoperative surgical patients, distinctive types of metabolic acidosis would correlate differently with the outcomes of high-risk surgeries. ⋯ We found that among patients with different types of acidosis, patients who developed hyperlactatemic metabolic acidosis postoperatively showed greater rates of renal dysfunction within 7 days and hyperlactatemic acidosis represented an independent factor on 30-day mortality in high-risk surgical patients.
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Anesthesia and analgesia · Nov 2016
ReviewMapping General Anesthetic Sites in Heteromeric γ-Aminobutyric Acid Type A Receptors Reveals a Potential For Targeting Receptor Subtypes.
IV general anesthetics, including propofol, etomidate, alphaxalone, and barbiturates, produce important actions by enhancing γ-aminobutyric acid type A (GABAA) receptor activation. In this article, we review scientific studies that have located and mapped IV anesthetic sites using photoaffinity labeling and substituted cysteine modification protection. These anesthetics bind in transmembrane pockets between subunits of typical synaptic GABAA receptors, and drugs that display stereoselectivity also show remarkably selective interactions with distinct interfacial sites. These results suggest strategies for developing new drugs that selectively modulate distinct GABAA receptor subtypes.
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Anesthesia and analgesia · Nov 2016
Comparative StudyThe CNAP™ Finger Cuff for Noninvasive Beat-To-Beat Monitoring of Arterial Blood Pressure: An Evaluation in Intensive Care Unit Patients and a Comparison with 2 Intermittent Devices.
Continuous and intermittent noninvasive measurements of arterial blood pressure (BP) have not been compared in the same population. In a large panel of intensive care unit patients, we assessed the agreement between CNAP™ (Continuous Noninvasive Arterial Pressure) finger cuff beat-to-beat monitoring of BP and reference intraarterial measurements. Two automated oscillometric brachial cuff devices were also tested: CNAP brachial cuff (used for CNAP finger cuff calibration) and an alternative device. The performance for detecting hypotension (intraarterial mean BP <65 mm Hg or systolic BP <90 mm Hg), response to therapy (therapy-induced increase in mean BP >10%), and hypertension (intraarterial systolic BP >140 mm Hg) was evaluated. We also assessed the between-calibration drift of CNAP finger cuff BP in specific situations: cardiovascular intervention or no intervention. ⋯ In a large population of intensive care unit patients, CNAP did not fulfill the ISO criteria and exhibited a relevant between-calibration drift. However, CNAP measurements collected within 4 minutes after calibration were reliable for detecting hypotension, as were oscillometric devices, while providing beat-to-beat measurements. Interestingly, an alternative automated brachial cuff was more reliable than the native one, used for calibration. This information is important to clinicians using those devices and for further development of the CNAP technology.
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Anesthesia and analgesia · Nov 2016
ReviewMesopontine Switch for the Induction of General Anesthesia by Dedicated Neural Pathways.
We review evidence that the induction of anesthesia with GABAergic agents is mediated by a network of dedicated axonal pathways, which convey a suppressive signal to remote parts of the central nervous system. The putative signal originates in an anesthetic-sensitive locus in the brainstem that we refer to as the mesopontine tegmental anesthesia area (MPTA). This architecture stands in contrast to the classical notion that anesthetic molecules themselves directly mediate anesthetic induction after global distribution by the vascular circulation. ⋯ Known connectivity of the MPTA provides a scaffold for defining the specific projection pathways that mediate each of the functional components of anesthesia. Because MPTA lesions do not induce coma, the MPTA is not a key arousal nucleus essential for maintaining the awake state. Rather, it appears be a "gatekeeper" of arousal function, a major element in a flip-flop switching mechanism that executes rapid and reversible transitions between the awake and the anesthetic state.
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Anesthesia and analgesia · Nov 2016
Clinical TrialNeuraxial Anesthesia Reduces Lymphatic Flow: Proof-of-Concept in First In-Human Study.
Dilation of lymphatic vessels may contribute to iatrogenic dissemination of cancer cells during surgery. We sought to determine whether neuraxial anesthesia reduces regional lymphatic flow. Using nuclear lymphoscintigraphy, 5 participants receiving spinal anesthesia for brachytherapy had lower extremity lymph flow at rest compared with flow under conditions of spinal anesthesia. ⋯ All analyzed limbs showed reduced lymph flow washout from the pedal injection site (range 62%-100%) due to neuraxial anesthesia. Lymph flow was abolished in 3 limbs. We report proof-of-concept that neuraxial anesthesia reduces lymphatic flow through a likely mechanism of sympathectomy.