Anesthesia and analgesia
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Anesthesia and analgesia · Jun 1998
A new and simple maneuver to position the left-sided double-lumen tube without the aid of fiberoptic bronchoscopy.
The double-lumen tube (DLT) is the mainstay of one-lung ventilation (OLV). We sought to determine whether this new intubation maneuver using an endobronchial cuff pressure could be substituted for verification by fiberoptic bronchoscope (FOB) in most conditions requiring left-sided DLT. Seventy-nine patients requiring video-assisted thoracoscopic surgery for pneumothorax or mediastinal mass, or open thoracotomy for lung or esophageal cancer were enrolled in this study. We used 35F (n = 23), 37F (n = 51), or 39F (n = 5) disposable polyvinyl chloride DLTs (Broncho-Cath; Mallinckrodt Medical Ltd., Athlone, Ireland), depending on the height and gender of the patients. The DLTs were inserted deeply until resistance was felt. At that time, the pilot of the endobronchial cuff was connected to the Control-Inflator (VBM Medizintechnik GmbH, Sulz am Neckar, Germany) via a three-way stopcock. The bronchial balloon was inflated with 1.0-2.0 mL of air through the stop-cock until approximately 30 cm H2O of cuff pressure was obtained. The DLT was slowly withdrawn until the pressure of the Control-Inflator decreased to approximately half the peak pressure during the initial phase of removal. At that time, the bronchial balloon was deflated, and the DLT was advanced approximately 1.0 cm (1.5 cm for the 39F DLT); using FOB, its position was checked by an independent observer not involved in positioning the DLTs. The ideal position was defined as that in which the carina was located at the same level with the middle 5 mm between the proximal margin of the endobronchial balloon and the circumferential black mark. In 50 patients the position was ideal, and in 27 patients it was not ideal but was within the margin of the safety. There were only two failures. We conclude that if a FOB is unavailable or inapplicable, this simple and new maneuver may be used as a substitute during the positioning of DLTs. ⋯ The correct position of the double-lumen tube is vital for one-lung ventilation, which has been confirmed with a fiberoptic bronchoscope. We devised a simple maneuver to position the double-lumen tube correctly without a fiberoptic bronchoscope.
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Anesthesia and analgesia · Jun 1998
Unplanned tracheal extubation outside the operating room: a quality improvement audit of hemodynamic and tracheal airway complications associated with emergency tracheal reintubation.
The incidence of hemodynamic and airway complications associated with tracheal reintubation after an unplanned extubation has not been established. Patients whose tracheas were emergently intubated outside the operating room were reviewed over a 27-mo period via a quality improvement vehicle to evaluate hemodynamic and airway complications. Data from a subset of patients (n = 57) who underwent tracheal reintubation after unplanned (self-) extubation were collected for analysis. Of the reintubations, 93% took place within 2 h of self-extubation. Of the patients, 72% had hemodynamic alterations and/or airway-related complications, including hypotension (35%), tachycardia (30%), hypertension (14%), multiple laryngoscopic attempts (22%), difficult laryngoscopy (16%), difficult intubations (14%), hypoxemia (14%), and esophageal intubation (14%). In addition, one surgical airway and one case of "cannot ventilate, cannot intubate" leading to cardiac arrest and death were recorded. These findings suggest that patients requiring reintubation will likely do so soon after self-extubation and that reintubation can be fraught with significant hemodynamic and airway complications. Less than one third of patients undergo a mishap-free reintubation. Strategies to decrease the self-extubation rate in the intensive care unit are needed to improve patient safety and to lessen the potential impact of emergency airway management. ⋯ Self-extubation by patients requiring mechanical ventilation can be life-threatening, and replacing the breathing tube often leads to hemodynamic and airway complications. Using this quality improvement audit, 57 self-extubating patients and the complications associated with replacing the breathing tube, which are numerous and can lead to significant morbidity and mortality, were analyzed.
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Anesthesia and analgesia · Jun 1998
The effect of rate of administration on brain concentrations of propofol in sheep.
A marked reduction in the dose of propofol required to achieve the onset of anesthesia with slower administration rates has previously been reported, but the mechanism of this phenomenon is unclear. We used a chronically instrumented sheep preparation to examine the effects of different administration rates of propofol on its distribution in the brain using mass balance principles to calculate brain concentrations. The administration of 100 mg of propofol i.v. at rates of 200, 50, and 20 mg/min had minimal effect on both the peak brain concentrations of propofol and the total amount of drug entering the brain. The more rapid administration rates increased the rate of uptake into the brain but resulted in large increases in peak arterial blood propofol concentrations. These faster administration rates have previously been associated with high arterial propofol concentrations and an increased risk of hypotension. Simulation of titration to an end point revealed that the dose sparing previously reported at induction with slow administration rates relates only to improved titration to effect, and does not result in more anesthesia for a given dose. Therefore, we conclude that the administration of propofol over 2 min provides a reasonable rate of induction and improved titration to effect, yet avoids excessively high arterial concentrations. ⋯ Alterations in the rate of administration of propofol in sheep have been shown to have little effect on the quantity of propofol delivered to the brain. At induction of anesthesia, administration rates of approximately 50 mg/min seem likely to provide improved titration to effect without excessively prolonging induction.
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Anesthesia and analgesia · Jun 1998
Editorial CommentPatient simulator competency testing: ready for takeoff?