Anesthesia and analgesia
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Anesthesia and analgesia · Sep 2017
ReviewBias, Confounding, and Interaction: Lions and Tigers, and Bears, Oh My!
Epidemiologists seek to make a valid inference about the causal effect between an exposure and a disease in a specific population, using representative sample data from a specific population. Clinical researchers likewise seek to make a valid inference about the association between an intervention and outcome(s) in a specific population, based upon their randomly collected, representative sample data. Both do so by using the available data about the sample variable to make a valid estimate about its corresponding or underlying, but unknown population parameter. ⋯ Bias and confounding are common potential explanations for statistically significant associations between exposure and outcome when the true relationship is noncausal. Understanding interactions is vital to proper interpretation of treatment effects. These complex concepts should be consistently and appropriately considered whenever one is not only designing but also analyzing and interpreting data from a randomized trial or observational study.
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Anesthesia and analgesia · Sep 2017
Clinical TrialPatients Undergoing Orthotopic Liver Transplantation Require Lower Concentrations of the Volatile Anesthetic Sevoflurane.
Sevoflurane is a volatile anesthetic commonly used to maintain anesthesia in patients with end-stage liver disease (ESLD) undergoing orthotopic liver transplantation (OLT). Growing evidence suggests that patients with ESLD have decreased anesthetic requirements compared to patients with preserved liver function. The potency of volatile anesthetics is expressed as the minimum alveolar concentration (MAC). In this prospective, blinded study, we compared the MAC of sevoflurane among patients with ESLD undergoing OLT and patients with normal liver function undergoing major abdominal surgery. ⋯ Our results suggest that the MAC of sevoflurane is lower in patients with ESLD than in patients with normal liver function after propofol-induced anesthesia. However, as we did not measure propofol concentrations at the time of skin incision, the difference in MAC should be interpreted with caution given that residual propofol may have been present at the time of skin incision.
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Anesthesia and analgesia · Sep 2017
ReviewAnesthetic Management of Patients With Inborn Errors of Metabolism.
Inborn errors of metabolism (IEM) are characterized by the body's inability to convert food into energy. The pathogenetic mechanism is based on defects in a variety of cellular enzymes. In addition to impairment of energy generation, accumulation of substrates may occur, which can deposit in tissue and lead to organ dysfunction. ⋯ For the anesthesiologist, comprehensive knowledge is difficult to attain because of the heterogeneity of this group and the low prevalence of specific diseases. The first part of this article reviews intermediary metabolism, whereas the second part aims to highlight important aspects in perioperative management of patients with IEM. Instead of reviewing each single disorder within the vast group of IEM, we provide a conceptual framework that will facilitate the understanding of main problems encountered in each of the disease subgroups.
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Anesthesia and analgesia · Sep 2017
Comparative Study Observational StudyThe First US Clinical Experience With Computer-Assisted Propofol Sedation: A Retrospective Observational Comparative Study on Efficacy, Safety, Efficiency, and Endoscopist and Patient Satisfaction.
Computer-assisted propofol sedation (CAPS) is now approved for moderate sedation of American Society of Anesthesiologists (ASA) class I and II patients undergoing routine endoscopy. As the first US medical center to adopt CAPS for routine clinical use, we compared patient and endoscopist satisfaction with CAPS versus midazolam and fentanyl (MF) sedation. ⋯ In low-risk patients, CAPS appears to be effective and efficient. CAPS is associated with higher satisfaction than MF for colonoscopies and, to a lesser extent, upper endoscopies.
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Anesthesia and analgesia · Sep 2017
Pragmatic Clinical TrialProphylactic Phenylephrine Infusions to Reduce Severe Spinal Anesthesia Hypotension During Cesarean Delivery in a Resource-Constrained Environment.
Phenylephrine infusions are considered as standard management for obstetric spinal hypotension, but there remains reluctance to implement them in resource-limited contexts. This prospective, alternating intervention study of patients undergoing elective or urgent cesarean delivery under spinal anesthesia compared a vasopressor bolus strategy to fixed-rate, low-dose prophylactic phenylephrine infusion with supplemental boluses. ⋯ Fewer patients receiving prophylactic phenylephrine infusions had severe hypotension (47.4% [n = 120/253] vs 62.1% [n = 157/253], P = .001, estimated relative risk 0.84, 95% confidence interval, 0.69-1.02), with no significant difference in the rate of hypertension (15% [n = 39/253] vs 11% [n = 27/253], P = .11, estimated relative risk 1.39, confidence interval 0.87-2.20). Guidelines for resource-constrained settings should consider a fixed, low-dose phenylephrine infusion in combination with rescue vasopressor bolus therapy.