Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2013
Comparative StudyUltrasound estimates for midline epidural punctures in the obese parturient: paramedian sagittal oblique is comparable to transverse median plane.
Spinal ultrasound (US) in the transverse median (TM) plane underestimates the distance to the epidural space in obese pregnant women, most likely because of compression of the subcutaneous tissue during the assessment, often required to compensate for poor visibility. We tested whether scanning in the paramedian sagittal oblique (PSO) plane compared with the TM plane resulted in a more precise estimate of the actual skin-epidural space measurement in this population. ⋯ The estimates of the US-determined distance to the epidural space in the PSO are comparable to those in the TM plane. The ability to use both estimates interchangeably for midline punctures may prove useful in patients presenting with poor visibility in the TM plane.
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Anesthesia and analgesia · Apr 2013
General anesthesia with sevoflurane decreases myocardial blood volume and hyperemic blood flow in healthy humans.
Preservation of myocardial perfusion during general anesthesia is likely important in patients at risk for perioperative cardiac complications. Data related to the influence of general anesthesia on the normal myocardial circulation are limited. In this study, we investigated myocardial microcirculatory responses to pharmacological vasodilation and sympathetic stimulation during general anesthesia with sevoflurane in healthy humans immediately before surgical stimulation. ⋯ In otherwise healthy subjects who are not subjected to surgical stimulation, MBF at rest and after sympathetic stimulation is preserved during sevoflurane anesthesia despite a decrease in myocardial blood volume. However, sevoflurane anesthesia reduces hyperemic MBF, and thus MBF reserve, in these subjects.
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Anesthesia and analgesia · Apr 2013
Occurrence of rapid eye movement sleep deprivation after surgery under regional anesthesia.
Sleep disturbances after general surgery have been described. In this study, we assessed rapid eye movement (REM) sleep in patients undergoing knee replacement surgery using a regional anesthetic technique. ⋯ Postoperative reduction of REM sleep also occurs after surgery and regional anesthesia.
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Anesthesia and analgesia · Apr 2013
Propofol increases vascular relaxation in aging rats chronically treated with the angiotensin-converting enzyme inhibitor captopril.
Both propofol use and advanced age are predictors of intraoperative hypotension. We previously demonstrated that propofol enhances vasodilation in mesenteric arteries from aged rats, partly due to increased nitric oxide (NO) bioavailability. Patients chronically treated with angiotensin-converting enzyme (ACE) inhibitors may exhibit refractory hypotension under general anesthesia. We hypothesized that propofol enhances NO-mediated vasodilation in arteries from aged rats chronically treated with ACE inhibitors. ⋯ Our results show that mesenteric arterial relaxation in response to propofol, both by direct stimulation and through modulation of endothelium-dependent mechanisms, is, in part, NO-dependent. In captopril-treated rats, propofol further increased arterial relaxation through a non-NO-dependent vasodilating pathway (e.g., endothelium-derived hyperpolarizing factor), which may account for enhanced vasodilation during propofol exposure in patients treated with ACE inhibitors.