Anesthesia and analgesia
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Anesthesia and analgesia · Mar 2004
Amplification by hyperoxia of coronary vasodilation induced by propofol.
We tested the hypothesis that in vitro coronary and myocardial effects of propofol (10-300 microM) should be significantly modified in an isolated and erythrocyte-perfused rabbit heart model in the absence (PaO(2) = 137 +/- 16 mm Hg, n = 12) or in the presence (PaO(2) = 541 +/- 138 mm Hg, n = 12) of hyperoxia. The induction of hyperoxia provoked a significant coronary vasoconstriction (-13% +/- 7%). Propofol induced increased coronary vasodilation in the presence of hyperoxia. Because high oxygen tension has been reported to induce a coronary vasoconstriction mediated by the closure of adenosine triphosphate-sensitive potassium channels, we studied the effects of propofol in 2 additional groups of hearts (n = 6 in each group) pretreated by glibenclamide (0.6 microM) and cromakalim (0.5 microM) in the absence and presence of hyperoxia, respectively. The pretreatment by glibenclamide induced a coronary vasoconstriction (-16% +/- 7%) which did not affect propofol coronary vasodilation. The pretreatment by cromakalim abolished the amplification of propofol coronary vasodilation in the presence of hyperoxia. Propofol induced a significant decrease in myocardial performance for a concentration >100 micro M both in the absence and presence of hyperoxia. We conclude that propofol coronary vasodilation is amplified in the presence of hyperoxia. This phenomenon is not explained by the previous coronary vasoconstriction induced by glibenclamide. However, the pretreatment of hearts by cromakalim abolished the amplification of propofol coronary vasodilation in the presence of hyperoxia. The myocardial effects of propofol were not affected by the presence of hyperoxia. ⋯ Propofol induced a coronary vasodilation that was amplified in the presence of hyperoxia. This phenomenon does not seem to be related to previous coronary vasoconstriction. The myocardial effects of propofol were not significantly modified in the presence of hyperoxia.
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Anesthesia and analgesia · Mar 2004
Case ReportsTransesophageal echocardiographic diagnosis of a liver laceration accompanied by hemodynamic instability.
Transesophageal echocardiography (TEE) is a useful adjunct in the evaluation of trauma patients, particularly in the area of aortic injury and cardiac tamponade. Little has been written on the use of this modality in the evaluation of extra-cardiac injury. We present a case of a trauma patient in whom TEE was used to evaluate hemodynamic instability; during the course of the examination a previously undiagnosed liver laceration was identified. We report the diagnosis of a liver laceration in a trauma patient by novel use of the transesophageal echocardiographic imaging modality.
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Anesthesia and analgesia · Mar 2004
Cost drivers in patient-controlled epidural analgesia for postoperative pain management after major surgery.
In this retrospective study, we determined efficiency, treatment length, and resource use for postoperative pain management with patient-controlled epidural analgesia (PCEA) in 350 consecutive patients undergoing major abdominal, thoracic, gynecological, or orthopedic surgery. Average pain scores on a visual analog scale were 16 +/- 23 and 9 +/- 16 (visual analog scale range, 0 to 100) on postoperative Days 1 and 3, respectively, and were similar among groups. The treatment length was 4.9 +/- 2.2 days in general surgical, 5.2 +/- 3.1 days in gynecological, and 4.5 +/- 2.8 days in orthopedic patients. The total volumes of the mixture of local anesthetic and opioid received epidurally were 707 +/- 507 mL, 770 +/- 576 mL, and 593 +/- 456 mL in the general surgical, gynecological, and orthopedic groups, respectively. The average total costs for all groups for the full treatment course with PCEA were 447 +/- 218 per case (1 equals approximately US dollar 1). Fifty-one percent of these costs were staff costs, 20% were costs for the applied drugs, 15% were costs for PCEA pumps and pump material, and 13% were costs for the initial catheter insertion. In the light of these costs and the availability of less costly alternatives, measurements for cost containment by using PCEA are recommended. Because treatment length is the main cost driver both for drug and staff costs, close monitoring of treatment length and a predefined migration path to alternative techniques after PCEA should be considered. ⋯ Patient-controlled epidural analgesia is increasingly used as first-line treatment for postoperative pain management. In this study, costs and cost drivers are analyzed for the first time for this new technique, based on 350 cases of pain therapy after major surgery in a university hospital.
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Anesthesia and analgesia · Mar 2004
Case ReportsLumbar epidural blood patch to treat a large, symptomatic postsurgical cerebrospinal fluid leak of 5 weeks duration in a 3-year-old.
A 3-yr-old with B-cell lymphoma presented with a 5-wk history of 400 mL/day cerebrospinal fluid (CSF) leak, which precluded chemotherapy, after placement of an Omaya reservoir and drain. Surgical repair was unsuccessful. Symptoms included irritability, failure to eat and noncommunication. After lumbar epidural blood patch with 7 mL the symptoms resolved immediately, allowing recommencement of chemotherapy. Epidural blood patch should be considered as possible early treatment for CSF leaks. ⋯ An epidural blood patch successfully treated a large cerebrospinal fluid leak of long duration in a 3-yr-old. Considering the distress of such a leak to the patient, staff, and parents, epidural blood patch may be considered as an early treatment option.
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Anesthesia and analgesia · Mar 2004
Functional residual capacity and respiratory mechanics as indicators of aeration and collapse in experimental lung injury.
Increased functional residual capacity (FRC) and compliance are two desirable, but seldom measured, effects of positive end-expiratory pressure (PEEP) in mechanically ventilated patients. To assess how these variables reflect the morphological lung perturbations during the evolution of acute lung injury and the morphological changes from altered PEEP, we correlated measurements of FRC and respiratory system mechanics to the degree of lung aeration and consolidation on computed tomography (CT). We used a porcine oleic acid model with FRC determinations by sulfur hexafluoride washin-washout and respiratory system mechanics measured during an inspiratory hold maneuver. Within the first hour, during constant volume-controlled ventilation with PEEP 5 cm H(2)O, FRC decreased by 45% +/- 15% (P = 0.005) and compliance decreased by 35% +/- 12% (P = 0.005). Resistance increased by 60% +/- 62% (P = 0.005). Only the FRC changes correlated significantly to the decreased aeration (R(2) = 0.56; P = 0.01) and the increased consolidation (R(2) = 0.43; P = 0.04) on CT. When the PEEP was changed to either 10 or 0 cm H(2)O, there were larger changes in FRC than in compliance. We conclude that, in our model, FRC was a more sensitive indicator of PEEP-induced aeration and recruitment of lung tissue and that FRC may be a useful adjunct to PaO(2) monitoring. ⋯ Lung injury was quantified on computed tomography and related to monitored values of functional residual capacity and mechanical properties of the respiratory system. We found the functional residual capacity to be a more sensitive marker of the lung perturbations than the compliance. It might be of value to include functional residual capacity in the monitoring of acute lung injury.