Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2009
Randomized Controlled Trial Comparative StudyThe effects of crystalloid and colloid preload on cardiac output in the parturient undergoing planned cesarean delivery under spinal anesthesia: a randomized trial.
Hypotension after spinal anesthesia for cesarean delivery remains a major clinical problem. Fluid preloading regimens together with vasopressors have been used to reduce its incidence. Previous studies have used noninvasive arterial blood pressure measurement and vasopressor requirements to evaluate the effect of preload. We used a suprasternal Doppler flow technique to measure maternal cardiac output (CO) and corrected flow time (FTc, a measure of intravascular volume) before and after spinal anesthesia after 3 fluid preload regimens. We hypothesized that colloid solutions, compared with crystalloid, would produce the largest increase in CO and have the lowest incidence of hypotension. ⋯ Despite CO and FTc increases after fluid preload, particularly with HES 1.0 L, hypotension still occurred. The data suggest that CO increases after these preload regimens cannot compensate for reductions in arterial blood pressure after spinal anesthesia.
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There is a need for safe, effective, and easy-to-administer systemic analgesia that ideally has rapid onset and offset, matches the time course of uterine contractions, and does not compromise the fetus. Although neuraxial blockade is the "gold standard" for labor analgesia, systemic analgesia is useful in those cases in which neuraxial analgesia is contraindicated, refused or simply not needed by the parturient, or when skilled anesthesia providers are not available. Because of its unique pharmacologic properties, remifentanil has been investigated, and is used clinically, to provide IV labor analgesia. In this focused review, we summarize the efficacy of remifentanil as a labor analgesic and review the current literature regarding its dose, mode of delivery, safety for the mother and fetus/neonate, as well as the scope for future research.
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Anesthesia and analgesia · Dec 2009
The role of 20-hydroxyeicosatetraenoic acid in cerebral arteriolar constriction and the inhibitory effect of propofol.
We conducted this study to examine, in cerebral parenchymal arterioles, whether 20-hydroxyeicosatetraenoic acid (20-HETE) induces constrictor responses via superoxide and whether propofol reduces this constriction. ⋯ Either neuronal transmission-dependent or exogenous 20-HETE seems to induce cerebral parenchymal arteriolar constriction via superoxide production resulting from NADPH oxidase activation. Propofol is likely to prevent this constriction via inhibition of NADPH oxidase, but not by its scavenging effect on superoxide.
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Anesthesia and analgesia · Dec 2009
Multicenter Study Clinical TrialGlucose as a marker of fluid absorption in bipolar transurethral surgery.
Historically, a reduced serum sodium concentration has been used to diagnose absorption of electrolyte-free irrigating fluid during transurethral resection of the prostate (TURP). In bipolar TURP, the irrigating solution contains electrolytes, thus invalidating the serum sodium method. In this study, we investigated whether glucose can be used to diagnose the absorption of irrigating fluid during TURP procedures. ⋯ In bipolar TURP, the addition of glucose to a concentration of 1% in the electrolyte-containing irrigation fluid can be used as a tracer of absorption that is comparable with measuring serum sodium after monopolar TURP.
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Anesthesia and analgesia · Dec 2009
Comparative StudyDoes patient position influence the reading of the bispectral index monitor?
Bispectral index (BIS) was developed to monitor patients' level of consciousness under general anesthesia. Several factors have been found to alter BIS readings without affecting the depth of anesthesia. We conducted a study to assess the impact of changing patients' position on BIS readings. ⋯ Changing a patient's position significantly affects the BIS values, which might affect the interpretation of anesthetic depth.