Anesthesia and analgesia
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Anesthesia and analgesia · May 2009
ReviewOptimal perfusion during cardiopulmonary bypass: an evidence-based approach.
In this review, we summarize the best available evidence to guide the conduct of adult cardiopulmonary bypass (CPB) to achieve "optimal" perfusion. At the present time, there is considerable controversy relating to appropriate management of physiologic variables during CPB. Low-risk patients tolerate mean arterial blood pressures of 50-60 mm Hg without apparent complications, although limited data suggest that higher-risk patients may benefit from mean arterial blood pressures >70 mm Hg. ⋯ Similarly, no distinct clinical benefits have been observed when open venous reservoirs have been compared to closed systems. In conclusion, there are currently limited data upon which to confidently make strong recommendations regarding how to conduct optimal CPB. There is a critical need for randomized trials assessing clinically significant outcomes, particularly in high-risk patients.
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Anesthesia and analgesia · May 2009
Randomized Controlled Trial Comparative StudyDose-dependent suppression of the electrically elicited stapedius reflex by general anesthetics in children undergoing cochlear implant surgery.
Cochlear implants stimulate the auditory nerve to enable hearing. Determining appropriate upper and lower limits of stimulation is essential for successful cochlear implantation. The intraoperative evoked stapedius reflex threshold (ESRT) and evoked compound action potential (ECAP) are commonly used to determine the limits of implant stimulation. In this study, we evaluated the dose-related effects of sevoflurane, desflurane, isoflurane, and propofol on the intraoperative ESRT and ECAP. ⋯ Volatile anesthetics suppress the stapedius reflex in a dose-dependent manner, suggesting that ESRT measurements acquired during volatile anesthesia will overestimate the maximum comfort level, which may cause discomfort postoperatively and adversely affect the child's adaptation to the implant. We advise against the use of volatile anesthetics for measurement of the stapedius reflex threshold during cochlear implant surgery.
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Anesthesia and analgesia · May 2009
ReviewTranscatheter aortic valve implantation: anesthetic considerations.
Aortic valvular stenosis remains the most common debilitating valvular heart lesion. Despite the benefit of aortic valve (AV) replacement, many high-risk patients cannot tolerate surgery. AV implantation treats aortic stenosis without subjecting patients to sternotomy, cardiopulmonary bypass (CPB), and aorta cross-clamping. ⋯ Transcatheter AV implantation relies on intraoperative hemodynamic manipulation for success. Transfemoral and transapical approaches pose unique management challenges, but both require rapid ventricular pacing, the management of hypotension and arrhythmias during beating-heart valve implantation, and TEE. Anesthesiologists will care for debilitated patients with aortic stenosis receiving transcatheter AV implantation.
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Amniotic fluid embolism is one of the most catastrophic complications of pregnancy. First described in 1941, the condition is exceedingly rare and the exact pathophysiology is still unknown. The etiology was thought to be embolic in nature, but more recent evidence suggests an immunologic basis. ⋯ Early recognition of amniotic fluid embolism is critical to a successful outcome. However, despite intensive resuscitation, outcomes are frequently poor for both infant and mother. Recently, aggressive and successful management of amniotic fluid embolism with recombinant factor VIIa and a ventricular assist device, inhaled nitric oxide, cardiopulmonary bypass and intraaortic balloon pump with extracorporeal membrane oxygenation have been reported and should be considered in select cases.
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Anesthesia and analgesia · May 2009
Randomized Controlled Trial Comparative StudyJugular venous oxygenation during hypothermic cardiopulmonary bypass in patients at risk for abnormal cerebral autoregulation: influence of alpha-Stat versus pH-stat blood gas management.
In a prospective, randomized study of cardiac surgical patients at risk for impaired cerebral blood flow autoregulation, we compared alpha-stat and pH-stat blood gas management. The 40 patients enrolled had age >70 yr, diabetes, prior stroke, or uncontrolled hypertension. ⋯ During rewarming, jugular venous desaturation (i.e., SjvO(2) <50%) occurred in 6 of 12 alpha-stat patients, but no pH-stat patients (P = 0.0006). Patients at risk for poor cerebral autoregulation have higher oxygen tensions and saturations if pH-stat blood gas management is used during cardiopulmonary bypass.