Anesthesia and analgesia
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Anesthesia and analgesia · Aug 2005
ReviewIntraoperative fluid restriction improves outcome after major elective gastrointestinal surgery.
Fluid therapy is one of the most controversial topics in perioperative management. There is continuing debate with regard to the quantity and the type of fluid resuscitation during elective major surgery. However, there are increasing reports of perioperative excessive intravascular volume leading to increased postoperative morbidity and mortality. ⋯ Furthermore, predetermined algorithms that suggest replacement of third space losses and losses through diuresis are unnecessary. Significant reduction in crystalloid volume can be achieved without encountering intraoperative hemodynamic instability or reduced (i.e., < 0.5 mL x kg(-1) x h(-1)) urinary output just by avoiding replacement of third space losses and preloading. Finally, there is a need for well-controlled studies in a well-defined patient population using clear criteria or end-points for perioperative fluid therapy.
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Anesthesia and analgesia · Aug 2005
Clinical TrialA pilot study of continuous transtracheal mixed venous oxygen saturation monitoring.
In this study, we investigated the feasibility and the accuracy of transtracheal mixed venous oxygen saturation (Svo(2)) monitoring. Ten patients undergoing thoracic surgery were included in this study. A single-use pediatric pulse oximetry sensor was attached to the double-lumen tube between the tracheal and bronchial cuff. After anesthesia was induced, the double-lumen tube was inserted into the trachea and adjusted to the proper position. During surgery, the pulmonary arterial blood was sampled every 3 min for 15 min to measure the Svo(2). The measurements made by the transtracheal pulmonary pulse oximeter (Sto(2)) were recorded at the same time that blood was sampled from the pulmonary artery for Svo(2) measurements. The levels of measurement agreement between the Sto(2) and the Svo(2) were analyzed using the Bland and Altman method. The mean +/- sd (range) oxygen saturation values during the data collecting period were 82.0% +/- 4.9% (72%-91%) for the Sto(2) and 82.2% +/- 5.5% (71%-91%) for the Svo(2), respectively. The linear correlation coefficient of the regression analysis between the Sto(2) and the Svo(2) was 0.934 (P < 0.05). A 95% confidence interval for absolute difference between the Sto(2) and the Svo(2) was 1.58%-2.09%. The mean +/- 2 sd difference between the Sto(2) and the Svo(2) was 0.12% +/- 3.97% on the Bland and Altman graph. We conclude that it is feasible to monitor the pulmonary artery oxygen saturation continuously by a transtracheal pulse oximetry technique and that it can be done so accurately. ⋯ Mixed venous oxygen saturation (Svo2) is a measure of the balance between oxygen supply and consumption throughout the whole body. Svo2 can be measured invasively by inserting a pulmonary artery catheter with the associated disadvantages of cost and potential for patient injury. In this study, we investigated the feasibility of noninvasive Svo2 measurement using a transtracheal pulse oximetry technique.
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Anesthesia and analgesia · Aug 2005
Clinical TrialPredictive factors of early postoperative urinary retention in the postanesthesia care unit.
Urinary retention is a common postoperative complication associated with bladder overdistension and the risk of permanent detrusor damage. The goal of this study was to determine predictive factors of early postoperative urinary retention in the postanesthesia care unit (PACU). We prospectively collected, in 313 adult patients, variables including age, gender, previous history of urinary tract symptoms, type of surgery and anesthesia, intraoperative administration of anticholinergics, amount of intraoperative fluids, IV morphine titration, and bladder volume on entry to the PACU. For each patient, bladder volume was measured by ultrasound on entry and before discharge from the PACU. Urinary retention was defined as a bladder volume larger than 600 mL with an inability to void within 30 min. Predictive factors were identified by multivariate analysis. The incidence of urinary retention in the PACU was 16%. In the multivariate analysis only the amount of intraoperative fluids (>or=750 mL; P = 0.02; odds ratio = 2.3), age (>or=50 yr; P = 0.008; odds ratio = 2.4), and bladder volume on entry to PACU (>or=270 mL; P = 0.0001; odds ratio = 4.8) were found to independently increase the risk of urinary retention. Considering the clinical impact of undiagnosed postoperative urinary retention, these results suggest systematic evaluation of bladder volume with a portable ultrasound device in the PACU, especially in patients with risk factors. ⋯ In this observational study, the ultrasound monitoring of bladder volume in the postanesthesia care unit (PACU) revealed that postoperative urinary retention occurred with an incidence of 16%. Age (>or=50 yr), amount of intraoperative fluid volume (>or=750 mL), and bladder volume on entry to PACU (>or=270 mL) were independent predictive factors for this complication.
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Anesthesia and analgesia · Aug 2005
Clinical TrialMonitoring activated clotting time for combined heparin and aprotinin application: an in vitro evaluation of a new aprotinin-insensitive test using SONOCLOT.
The kaolin-based activated clotting time (ACT) is commonly used for monitoring heparin-induced anticoagulation alone and combined with aprotinin during cardiopulmonary bypass. However, aprotinin prolongs ACT measurements. Recently, a new so-called 'aprotinin-insensitive' ACT test (SaiACT) has been developed for the SONOCLOT analyzer. In this study we evaluated and compared this new test for the SONOCLOT analyzer in vitro with an established kaolin-based ACT from HEMOCHRON (HkACT). Twenty-five patients undergoing elective valve surgery donated 80 mL of blood after induction of anesthesia. The blood was withdrawn in citrated tubes and processed to analyze effects of heparin (0, 1, 2, and 3 U x mL(-1)), aprotinin (0, 200 kIU x mL(-1)), and 25% hemodilution with calcium-free lactated Ringer's solution on ACT measurements. A total of 400 blood samples were analyzed and ACT was measured in a wide, clinically relevant range in duplicate with SaiACT and HkACT. Addition of aprotinin to heparinized blood samples induced no significant changes of SaiACT measurements. By contrast, HkACT readings increased significantly: aprotinin prolonged HkACT in heparinized blood samples by 20% +/- 37% (2 U x mL(-1)) and 24% +/- 18% (3 U x mL(-1)), respectively, and in vitro hemodilution increased this effect. ⋯ Current standard techniques to measure heparin-induced anticoagulation during cardiopulmonary bypass are affected by aprotinin, a drug widely used in this setting. The aim of this study was to investigate in vitro a new, so-called 'aprotinin-insensitive' test from SONOCLOT to measure heparin-induced anticoagulation more reliably in combination with aprotinin.
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Anesthesia and analgesia · Aug 2005
A retrospective analysis of a remifentanil/propofol general anesthetic for craniotomy before awake functional brain mapping.
We performed this study to summarize drug dosing, physiologic responses, and anesthetic complications from an IV general anesthetic technique for patients undergoing craniotomy for awake functional brain mapping. Review of 98 procedures revealed "most rapid" IV infusion rates for remifentanil 0.05, 0.05-0.09 microg x kg(-1) x min(-1) and propofol 115, 100-150 microg x kg(-1) x min(-1). The infusions lasted for 78, 58-98 min. Intraoperative emergence from general anesthesia was 9 (6-13) min after discontinuing IV infusions to allow for brain mapping and was independent of infusion duration and duration of craniotomy before mapping. Spontaneous ventilation was generally satisfactory during drug infusion, as evidenced by Sao(2) = 95% (92%-98%) and Paco(2) = 50 (47-55) mm Hg. However, we recorded at least one 30-s epoch of apnea in 69 of 96 patients. Maximum systolic arterial blood pressure was 150 (139-175) mm Hg and minimal systolic arterial blood pressure was 100 (70-150) mm Hg during drug infusion. Three patients experienced intraoperative seizures. Two patients did not tolerate the awake state and required reinduction of general anesthesia. No patients required endotracheal intubation or discontinuation of surgery. This general anesthetic technique is effective for craniotomy with awake functional brain mapping and offers an alternative to continuous wakefulness or other IV sedation techniques. ⋯ An IV general anesthetic technique using remifentanil and propofol is an effective method allowing for reliable emergence for intraoperative awake functional brain mapping during craniotomy.