Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2003
Randomized Controlled Trial Clinical TrialThe dose effect of ephedrine on the onset time of vecuronium.
A small dose of ephedrine decreases the onset time of rocuronium and cisatracurium; however, ephedrine might be associated with adverse hemodynamic effects. The appropriate dose of ephedrine has not been determined. We, therefore, studied 120 patients anesthetized with fentanyl 2 microg/kg and propofol 2-2.5 mg/kg who were randomly divided to receive either ephedrine (30, 70, or 110 microg/kg) or saline. During propofol anesthesia, the neuromuscular block was monitored by mechanomyography by using submaximal current of train-of-four stimulation every 10 s. To determine cardiac output, a transcutaneous Doppler probe was placed externally at the suprasternal notch. Tracheal intubation was performed by a blinded investigator at 2 min after vecuronium. Neuromuscular block, intubating conditions, and hemodynamic effects were measured during the induction of anesthesia. Both ephedrine 70 and 110 microg/kg improved intubating conditions at 2 min after vecuronium; however, 110 microg/kg was associated with adverse hemodynamic effects. We conclude that ephedrine 70 microg/kg given before the induction of anesthesia improved intubating conditions at 2 min after vecuronium, probably by increased cardiac output without significant adverse hemodynamic effects. ⋯ Ephedrine 70 microg/kg given before the induction of anesthesia improved tracheal intubating conditions at 2 min after vecuronium by increased cardiac output without significant adverse hemodynamic effects.
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Anesthesia and analgesia · Apr 2003
Comparative Study Clinical TrialA comparison of the PAxpress and face mask plus Guedel airway by inexperienced personnel after mannequin-only training.
The PAxpress (PAX) is a new extraglottic airway device consisting of an anatomically curved tube, an inflatable circular cuff in the midsection, a noninflatable gilled conical cuff at the distal end, and an anterior-facing, rectangular hooded vent between the two cuffs. We compared the ability of nurses with no previous airway management experience to ventilate the lungs of 45 ASA physical status I and II anesthetized, paralyzed patients using either the PAX or face mask and Guedel airway (FM/GA) after mannequin-only training. Nurses were asked to ventilate the patient to an expired target tidal volume of 7 mL/kg and then to the maximum tidal volume achievable. The FM/GA was used first and the then the PAX. The target tidal volume was achieved in all patients with both devices. There were no differences in the time taken (PAX, 41 +/- 15 s; FM/GA, 39 +/- 25 s) or the number of insertion attempts to achieve the target tidal volume. There were no differences in the frequency of esophageal leaks at the target (PAX, 9%; FM/GA, 4%) and maximum tidal volume (PAX, 51%; FM/GA, 49%). The maximal tidal volume (1261 +/- 306 versus 958 +/- 220 mL; P < 0.0001) and peak airway pressure (37 +/- 5 versus 28 +/- 6 cm H(2)O; P < 0.0001) was larger for the PAX, but blood was detected more frequently (22% versus 0%; P = 0.001). We conclude that ventilation to a target tidal volume of 7 mL/kg in anesthetized, paralyzed adults is equally successful for the PAX and FM/GA by inexperienced nurses after mannequin-only training. However, the maximal tidal volume and peak airway pressure is larger and airway trauma more common with the PAX. ⋯ Ventilation to a target tidal volume of 7 mL/kg in anesthetized, paralyzed adults is equally successful for the PAxpress (PAX) and Face Mask/Guedel Airway by inexperienced nurses after mannequin-only training. However, the maximal tidal volume and peak airway pressure is larger and airway trauma more common with the PAX.
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Anesthesia and analgesia · Apr 2003
Clinical TrialPenetration of intravenous hydroxyethyl starch into the cerebrospinal fluid in patients with impaired blood-brain barrier function.
Hypovolemic patients with impairment of the blood-brain barrier may receive IV hydroxyethyl starch (HES) to stabilize cardiovascular function and to increase cerebral perfusion pressure. It is not known whether HES can penetrate into the cerebrospinal fluid (CSF) under those conditions. We investigated plasma and CSF levels of HES after IV infusion in patients with suspected disturbance of the blood-brain barrier. Eight adult patients were studied who were being treated for head trauma or subarachnoid hemorrhage, with an external CSF drain in place. All patients exhibited radiographic signs of blood-brain barrier impairment diagnosed by cerebral computed tomography. After IV infusion of 500 to 1000 mL of HES 200,000/0.5, plasma HES levels were measured. Additionally, all CSF that was drained within 8 h after the HES infusion was collected, and HES concentrations were measured. All patients had detectable HES plasma concentrations (3.41 to 9.95 mg/mL). In contrast, no HES could be detected in the CSF of any patient. These data indicate that IV HES 200,000/0.5 does not penetrate into the CSF in patients with disturbed blood-brain barrier function after subarachnoid hemorrhage or head trauma. Further study is required to determine whether HES penetrates into the intracranial interstitium, despite the absence of HES in the CSF. ⋯ Patients may receive IV hydroxyethyl starch (HES) after head trauma or subarachnoid hemorrhage. The results of the present study indicate that in patients with suspected blood-brain barrier impairment, HES does not penetrate from the plasma into the cerebrospinal fluid.
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Anesthesia and analgesia · Apr 2003
Case ReportsAirway difficulty after a brachial plexus subclavian perivascular block.
We report a case of upper airway obstruction after subclavian perivascular block in a patient with a preexisting unrecognized paralyzed vocal cord on the opposite side. We discuss the incidence of vocal cord paralysis after subclavian perivascular block and the risk of airway compromise if contralateral vocal cord paralysis is known or suspected.
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Economic considerations suggest that it is desirable to keep operating rooms fully used when staffed, but the optimum utilization of an operating room (OR) is not known. We created a simulation of an OR to define optimum utilization. We set operational goals of having cases start within 15 min of the scheduled time and of having the cases end no more than 15 min past the scheduled end of the day. Within these goals, a utilization of 85% to 90% is the highest that can be achieved without delay or running late. Increasing the variability of case duration decreases the utilization that can be achieved within these targets. ⋯ Using a simulated operating room (OR), the authors demonstrate that OR utilization higher than 85% to 90% leads to patient delays and staff overtime. Increased efficiency of an OR comes at a cost of patient convenience.