Anesthesia and analgesia
-
Anesthesia and analgesia · Mar 2004
Randomized Controlled Trial Comparative Study Clinical TrialNarcotrend index versus bispectral index as electroencephalogram measures of anesthetic drug effect during propofol anesthesia.
The Narcotrend monitor (MonitorTechnik, Bad Bramstedt, Germany) performs an automatic analysis of the electroencephalogram (EEG) during anesthesia based on a visual assessment of the raw EEG. Its newest software version 4.0 includes a dimensionless index that, similar to the bispectral index (BIS), ranges from 100 (awake) to 0. We compared the performance of Narcotrend index and BIS as EEG measures of anesthetic drug effect during propofol anesthesia. Eighteen adult patients scheduled for radical prostatectomy were investigated. An epidural catheter was placed in the lumbar space and electrodes for BIS (version XP; Aspect Medical Systems, Natick, MA) and Narcotrend were positioned as recommended by the manufacturers. Narcotrend index, BIS values, and propofol plasma and effect site concentrations as parallelly simulated by Rugloop software (Department of Anesthesia, Ghent University, Belgium) were automatically recorded in intervals of 5 s. Induction of anesthesia consisted of a fentanyl bolus and a propofol infusion. After endotracheal intubation, patients received 15 mL bupivacaine 0.5% epidurally, and 45 min later propofol dosages were subsequently increased and decreased twice. Simulated propofol effect site concentrations ranged from 2.0 +/- 0.4 microg/mL (smallest) to 6.3 +/- 1.3 microg/mL (largest) during these subsequent increases and decreases of propofol. In terms of prediction probability (P(K)) the performance of the Narcotrend index (P(K) = 0.88 +/- 0.03) to predict propofol effect site concentrations was comparable to the BIS (P(K) = 0.85 +/- 0.04). Using the respective EEG index as a measure of drug effect the mean k(e0) was calculated as 0.20 +/- 0.05 min(-1) for Narcotrend index and 0.16 +/- 0.07 min(-1) for BIS. In the observed propofol concentration range Narcotrend index detected differences in EEG dynamics as well as BIS. ⋯ This study in 18 adult patients undergoing radical prostatectomy describes the relationship between Narcotrend index and bispectral index versus predicted propofol effect compartment concentrations. In terms of prediction probability, the performance of the Narcotrend index and the bispectral index to predict propofol effect site concentrations was comparable.
-
Anesthesia and analgesia · Mar 2004
Randomized Controlled Trial Clinical TrialThe effects of different ventilatory settings on pulmonary and systemic inflammatory responses during major surgery.
Mechanical ventilation with high tidal volumes (V(T)) and zero or low positive end-expiratory pressure increased mediator release to inflammatory stimuli or acute lung injury. We studied whether mechanical ventilation modifies the inflammatory responses during major thoracic or abdominal surgery. Sixty-four patients undergoing elective thoracotomy (n = 34) or laparotomy (n = 30) were randomized to receive either mechanical ventilation with V(T) = 12 or 15 mL/kg ideal body weight, respectively, and zero end-expiratory pressure, or V(T) = 6 mL/kg ideal body weight with positive end-expiratory pressure of 10 cm H(2)O. In 62 patients who completed the study, arterial oxygenation was not different between groups. Tumor necrosis factor, interleukin (IL)-1, IL-6, IL-8, IL-10, and IL-12 were determined by cytometric bead array in plasma after 0, 1, 2, and 3 h and in tracheal aspirates after 3 h of mechanical ventilation. Data were log-transformed and analyzed using parametric or nonparametric tests, as indicated. All plasma mediators increased more during abdominal than during thoracic surgery, although the differences were small. However, neither time course nor concentrations of pulmonary or systemic mediators differed between the two ventilatory settings. Our data suggest that the ventilatory settings we studied do not affect inflammatory reactions during major surgery within 3 h. ⋯ In 62 patients undergoing elective major thoracic or abdominal surgery, mechanical ventilation with low tidal volumes and positive end-expiratory pressure or high tidal volumes and zero end-expiratory pressure did not result in different pulmonary or systemic levels of measured inflammatory markers.
-
Anesthesia and analgesia · Mar 2004
Randomized Controlled Trial Clinical TrialAdding dexmedetomidine to lidocaine for intravenous regional anesthesia.
Dexmedetomidine is approximately 8 times more selective toward the alpha-2-adrenoceptors than clonidine. It decreases anesthetic requirements by up to 90% and induces analgesia in patients. We designed this study to evaluate the effect of dexmedetomidine when added to lidocaine in IV regional anesthesia (IVRA). We investigated onset and duration of sensory and motor blocks, the quality of the anesthesia, intraoperative-postoperative hemodynamic variables, and intraoperative-postoperative pain and sedation. Thirty patients undergoing hand surgery were randomly assigned to 2 groups to receive IVRA. They received 40 mL of 0.5% lidocaine and either 1 mL of isotonic saline (group L, n = 15) or 0.5 microg/kg dexmedetomidine (group LD, n = 15). Sensory and motor block onset and recovery times and anesthesia quality were noted. Before and after the tourniquet application at 5, 10, 15, 20, and 40 min, hemodynamic variables, tourniquet pain and sedation, and analgesic use were recorded. After the tourniquet deflation, at 30 min, and 2, 4, 6, 12, and 24 h, hemodynamic variables, pain and sedation values, time to first analgesic requirement, analgesic use, and side effects were noted. Shortened sensory and motor block onset times, prolonged sensory and motor block recovery times, prolonged tolerance for the tourniquet, and improved quality of anesthesia were found in group LD. Visual analog scale scores were significantly less in group LD in the intraoperative period and 30 min, and 2, 4, and 6 h after tourniquet release. Intra-postoperative analgesic requirements were significantly less in group LD. Time to first analgesic requirements was significantly longer in group LD in the postoperative period. We conclude that the addition of 0.5 microg/kg dexmedetomidine to lidocaine for IVRA improves quality of anesthesia and perioperative analgesia without causing side effects. ⋯ This study was designed to evaluate the effect of dexmedetomidine when added to lidocaine for IV regional anesthesia. This is the first clinical study demonstrating that the addition of 0.5 microg/kg dexmedetomidine to lidocaine for IV regional anesthesia improves quality of anesthesia and intraoperative-postoperative analgesia without causing side effects.
-
Anesthesia and analgesia · Mar 2004
Comparative StudyClinical evaluation of the effects of signal integrity and saturation on data availability and accuracy of Masimo SE and Nellcor N-395 oximeters in children.
Pulse oximetry manufacturers have introduced technologies that claim improved detection of hypoxemic events. Because improvements in signal processing and data rejection algorithms may differentially affect data reporting, we compared the data reporting and signal heuristic performance and agreement among the Nellcor N-395, Masimo SET, and GE Solar 8000 oximeters under a spectrum of conditions of signal integrity and arterial oxygen saturations. A blinded side-by-side comparison of technologies was performed in 27 patients, and data were analyzed for time of data availability, measures of agreement and signal heuristics, and warnings stratified by signal integrity and SpO(2). The Solar 8000 had less total data dropout than either of the new technologies. Masimo's LoSIQ (signal quality) heuristic rejected less data than Nellcor's MOT/PS (motion/pulse search) flag. When no signal heuristic was displayed, there was little difference in precision and bias between the two newer technologies; however, agreement between devices deteriorated in the presence of SIQ, MOT, or hypoxemia. Both newer devices flagged questionable data, but their use of different rejection algorithms resulted in different probabilities of presenting data. Therefore, with poor SIQ or during hypoxemia, the Nellcor N-395 and Masimo oximeters are not clinically equivalent to each other or to the older Solar 8000 oximeter. ⋯ We compared new pulse oximeters from Nellcor and Masimo and found that, with good signal conditions, both new devices performed similarly to older technology. Overall, Masimo reported less data as questionable than Nellcor. With poor signal conditions or during hypoxemia, the new devices are not clinically equivalent to each other or to the older technology.
-
Anesthesia and analgesia · Mar 2004
Clinical TrialThe intubating laryngeal mask airway facilitates tracheal intubation in the lateral position.
Although the difficulty of tracheal intubation in the lateral position has not been systematically evaluated, airway loss during surgery in a laterally positioned patient may have hazardous consequences. We explored whether the intubating laryngeal mask airway (ILMA) facilitates tracheal intubation in patients with normal airway anatomy, i.e., Mallampati grade