Anesthesia and analgesia
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Anesthesia and analgesia · May 2016
The Recovery Time of Myometrial Responsiveness After Oxytocin-Induced Desensitization in Human Myometrium In Vitro.
Postpartum hemorrhage secondary to uterine atony is a leading cause of maternal morbidity. Prolonged exposure to oxytocin for labor augmentation can result in the desensitization phenomenon, a decrease in the responsiveness of myometrium to further oxytocin. It is currently not known whether waiting for a specific time interval after the cessation of oxytocin allows the oxytocin receptors to resensitize and recover, thereby improving subsequent oxytocin-induced myometrial contractility. We aimed to investigate the effect of a rest period of 30, 60, and 90 minutes after oxytocin administration on the recovery of oxytocin-desensitized human myometrium in vitro. We hypothesized that the longer the rest period, the better the responsiveness and subsequent oxytocin-induced contractility of the myometrium. ⋯ Our study shows that oxytocin pretreatment attenuates oxytocin-induced contractility in human myometrium despite a rest period of up to 90 minutes after oxytocin administration. However, we were unable to determine whether increasing the rest period from 30 to 90 minutes results in improvement in myometrial contractility because of our small sample size relative to the variability in the contractile parameters. Further laboratory and clinical in vivo studies are necessary to determine whether a rest period up to 90 minutes results in improvement in myometrial contractility. In addition, further experimental studies are necessary to determine the key mechanisms of oxytocin receptor resensitization.
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Anesthesia and analgesia · May 2016
ReviewDoes Obstructive Sleep Apnea Influence Perioperative Outcome? A Qualitative Systematic Review for the Society of Anesthesia and Sleep Medicine Task Force on Preoperative Preparation of Patients with Sleep-Disordered Breathing.
Obstructive sleep apnea (OSA) is a commonly encountered problem in the perioperative setting even though many patients remain undiagnosed at the time of surgery. The objective of this systematic review was to evaluate whether the diagnosis of OSA has an impact on postoperative outcomes. We performed a systematic review of studies published in PubMed-MEDLINE, MEDLINE In-Process, and other nonindexed citations, Embase, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Health Technology Assessment up to November 2014. ⋯ The majority reported worse outcomes for a number of events, including pulmonary and combined complications, among patients with OSA versus the reference group. The association between OSA and in-hospital mortality varied among studies; 9 studies showed no impact of OSA on mortality, 3 studies suggested a decrease in mortality, and 1 study reported increased mortality. In summary, the majority of studies suggest that the presence of OSA is associated with an increased risk of postoperative complications.
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Anesthesia and analgesia · May 2016
Randomized Controlled Trial Comparative StudyThe Risk of Falls After Total Knee Arthroplasty with the Use of a Femoral Nerve Block Versus an Adductor Canal Block: A Double-Blinded Randomized Controlled Study.
Adductor canal block (ACB) has emerged as an appealing alternative to femoral nerve block (FNB) that produces a predominantly sensory nerve block by anesthetizing the saphenous nerve. Studies have shown greater quadriceps strength preservation with ACB compared with FNB, but no advantage has yet been shown in terms of fall risk. The Tinetti scale is used by physical therapists to assess gait and balance, and total score can estimate a patient's fall risk. We designed this study to test the primary hypothesis that FNB results in a greater proportion of "high fall risk" patients postoperatively using the Tinetti score compared with ACB. ⋯ ACB results in greater preservation of quadriceps muscle strength. Although we did not detect a significant reduction in fall risk when compared with FNB, based on the upper limit of the relative risk, it may very well be present. Further study is needed with a larger sample size.
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Anesthesia and analgesia · May 2016
Randomized Controlled TrialThe Effect of Dexmedetomidine on Postoperative Opioid Consumption and Pain After Major Spine Surgery.
Adult deformity correction spine surgery can be associated with significant perioperative pain because of inflammatory, muscular, neuropathic, and postsurgical pain. α-2 Agonists have intrinsic antinociceptive and antihyperalgesic properties that can potentially reduce both postoperative opioid consumption and pain. We hypothesized that intraoperative dexmedetomidine would reduce postoperative opioid consumption and improve pain scores in deformity correction spine surgery. ⋯ Intraoperative dexmedetomidine does not reduce postoperative opioid consumption or improve pain scores after multilevel deformity correction spine surgery.
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Anesthesia and analgesia · May 2016
ReviewProthrombin Complex Concentrates for Bleeding in the Perioperative Setting.
Prothrombin complex concentrates (PCCs) contain vitamin K-dependent clotting factors (II, VII, IX, and X) and are marketed as 3 or 4 factor-PCC formulations depending on the concentrations of factor VII. PCCs rapidly restore deficient coagulation factor concentrations to achieve hemostasis, but like with all procoagulants, the effect is balanced against thromboembolic risk. The latter is dependent on both the dose of PCCs and the individual patient prothrombotic predisposition. ⋯ Importantly, in patients with perioperative bleeding, other considerations should include treating additional sources of coagulopathy such as hypofibrinogenemia, thrombocytopenia, and platelet disorders or surgical sources of bleeding. Thromboembolic risk from excessive PCC dosing may be present well into the postoperative period after hemostasis is achieved owing to the relatively long half-life of prothrombin (factor II, 60-72 hours). The integration of PCCs into comprehensive perioperative coagulation treatment algorithms for refractory bleeding is increasingly reported, but further studies are needed to better evaluate the safe and effective administration of these factor concentrates.