Anesthesia and analgesia
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Anesthesia and analgesia · May 2001
Clinical Trial Controlled Clinical TrialThe analgesic efficacy of tramadol is impaired by concurrent administration of ondansetron.
Tramadol has weak opioid properties, and an analgesic effect that is mediated mainly by inhibition of the reuptake of norepinephrine and serotonin (5-hydroxytryptamine [5-HT]) and facilitation of 5-HT release (1,2) at the spinal cord. Because 5-HT3 receptors play a key role in pain transmission at the spinal level (3), the 5-HT3 antagonist ondansetron may decrease the efficacy of tramadol, as suggested in an abstract by Maroof et al. ⋯ Early postoperative pain scored differed significantly between the test groups. We therefore tested the hypothesis that the tramadol requirement by patient-controlled analgesia (PCA) may be increased when ondansetron is administered for antiemetic prophylaxis.
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Anesthesia and analgesia · May 2001
Comparative StudyThe disposition of the cervical spine and deformation of available cord space with conventional- and balloon laryngoscopy-guided laryngeal intubation: a comparative study.
Orotracheal intubation causes cervical spine (C-spine) extension and potential (hypothetical) space available for the cord (SAC)-deformation. In the present study, we determined and compared the changes induced by conventional- and balloon laryngoscopy-guided orolaryngeal intubation in the upper C-spine's osseous unit-orientation, segmental angulation, segmental SAC-sagittal surface areas (SSAs), segmental/total posterior SAC-aspect, and segmental SAC-width. Eight healthy volunteers were enrolled. A set of neutral head position (baseline)- and two sets of intubation-lateral C-spine radiographs were obtained. Relative to baseline, both intubation techniques induced significant changes in the occiput (OCC)-, third cervical vertebra (C3)-, C4-, and C5-orientation, the OCC-C1-segmental angulation, all the segmental SAC-SSAs, and the OCC-C1-, and C1-2-posterior SAC-aspect (P < 0.05 to < 0.001); conventional intubation caused additional significant changes in C2-orientation, total (OCC through C5)-posterior SAC-aspect, and OCC-C1-SAC-width (P < 0.05 to < 0.001). Relative to conventional intubation, balloon-assisted intubation caused less change in C3-orientation and C2-3-SAC-width (P < 0.05), and less reduction in OCC-C1-, C1-2-, and C4-5-SAC-SSAs (P < 0.05 to < 0.01). Orotracheal intubation should be cautiously performed in patients with space-occupying upper-C-spine-SAC lesions, even if there is no concomitant osseous/ligamentous pathology. In such cases, balloon laryngoscopy may be chosen over the conventional technique, because it causes less SAC deformation. ⋯ This study shows that direct laryngoscopy-guided orotracheal intubation causes deformation of the upper cervical space available for the cord, even in the absence of cervical spine instability. These effects are attenuated with balloon laryngoscopy, and thus, its use is recommended in patients with space-occupying lesions within the spinal canal.
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Anesthesia and analgesia · May 2001
Case ReportsPerioperative care of a patient with acute fatty liver of pregnancy.
Acute fatty liver of pregnancy (AFLP) is a late gestational complication with biochemical similarities to the inherited disorders of mitochondrial fatty acid oxidation and clinical similarities to fulminant hepatic failure. The following case illustrates our perioperative management of this rarely encountered disorder.
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Anesthesia and analgesia · May 2001
Can initial distribution volume of glucose predict hypovolemic hypotension after radical surgery for esophageal cancer?
We recently reported that the initial distribution volume of glucose (IDVG) reliably measures the central extracellular fluid volume in the presence or absence of fluid gain or loss. We examined which variables, including IDVG, can predict subsequent hypovolemic hypotension produced by the continuous shift of the extracellular fluid from the central to the peripheral compartment early after radical surgery for esophageal cancer. IDVG and plasma volume were calculated after measuring cardiac index (CI), central venous pressure, and pulmonary artery wedge pressure immediately after admission to the intensive care unit. Intraoperative fluid balance and urine volume were also recorded. Postoperative hypovolemic hypotension was clinically defined as systolic blood pressure < 80 mm Hg responsive to IV fluid administration. Either IDVG < 105 mL/kg or CI < 3.4 L. min(-1). m(-2) was associated with subsequent hypovolemic hypotension (P = 0.002 for the former and P = 0.00 03 for the latter), while remaining variables were not. IDVG and CI were well correlated (r = 0.8 7, n = 25, P = 0.0001). Our results suggest that IDVG can help predict the subsequent hypovolemic hypotension early after radical surgery for esophageal cancer. ⋯ Routine cardiovascular variables immediately after major surgery cannot predict the subsequent hypovolemic hypotension produced by the shift of the extracellular fluid. Glucose dilution using glucose 5 g and a one-compartment model can predict it simply and rapidly.
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Anesthesia and analgesia · May 2001
Prolonged sedation with propofol in the rat does not result in sleep deprivation.
The use of propofol provides sedation without prolonging emergence in patients in the Intensive Care Unit. When prolonged, however, continuous sedation may overlap with naturally occurring sleep periods and potentially increase the risk of sleep deprivation. We modified an established rat model of sleep to determine whether prolonged, continuous sedation results in sleep deprivation. Rats were continuously sedated for a 12-h period overlapping completely with their normal sleep phase. Electroencephalogram (EEG) and movement data were collected before and after the sedation period. Rats were evaluated for EEG and movement evidence of sleep deprivation after sedation. When compared with baseline, the time spent in rapid eye movement (REM) and non-REM sleep was decreased during the first 4 h after sedation. The duration of non-REM sleep bouts was not altered. Power in the delta band (0.5-4 Hz) during non-REM sleep was diminished during the first 2 h only. Movements were reduced during the first hour after emergence from sedation only. In summary, no EEG or behavioral evidence of sleep deprivation was observed on emergence from sedation. These results imply that sedation is associated with a restorative process reversing the natural accumulation of sleep need that occurs during wakefulness. ⋯ Prolonged sedation in the Intensive Care Unit may alter the restorative effects of naturally occurring sleep. We sedated rats during their sleep phase to determine whether sedation interferes with sleep. Upon emergence, no evidence of sleep deprivation was observed. Sedation may thus be associated with a restorative effect similar to sleep.