Anesthesia and analgesia
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Anesthesia and analgesia · Oct 2004
Randomized Controlled Trial Comparative Study Clinical TrialIsoflurane inhalation enhances increased physiologic deadspace volume associated with positive pressure ventilation and compromises arterial oxygenation.
Abnormally increased physiologic deadspace volume (Vd(phys)), consisting of alveolar deadspace volume and airway deadspace volume, is one of several causative factors predisposing to compromised arterial blood gas exchange. We compared the effects of two methods of general anesthesia on Vd(phys) when combined with positive pressure ventilation (PPV): total IV anesthesia (TIVA) and inhaled anesthesia with isoflurane. Forty patients with no history of pulmonary pathology undergoing elective surgery in the supine position were studied. ⋯ Furthermore, isoflurane inhalation (1.15% end-tidal concentration) resulted in impaired arterial oxygenation, as evidenced by a significant decrease in the Pao(2)/fractional inspired oxygen concentration ratio compared with baseline values from 387 +/- 35 to 310 +/- 70 (P < 0.05). Although significant increases in Vd(phys) resulted with PPV combined with TIVA, these adverse changes were much less compared with isoflurane inhalation and PPV. These findings may apply to subjects with compromised pulmonary function (i.e., acute respiratory distress syndrome or severe inhalational burn injury).
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Anesthesia and analgesia · Oct 2004
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of bispectral index and rapidly extracted auditory evoked potentials index responses to noxious stimulation during sevoflurane anesthesia.
In 21 patients given sevoflurane anesthesia, we simultaneously compared the abilities of Bispectral Index (BIS) and rapidly extracted auditory evoked potentials index (AAI) to display the effect of an increasing cerebral concentration of sevoflurane, with and without noxious stimulation. In addition to BIS/AAI, hemodynamic variables were monitored. After titrating sevoflurane to BIS = 50-55 during 15 min, the end-tidal concentration of sevoflurane (1.46% +/- 0.20%) was doubled followed by a noxious stimulus, laryngoscopy, applied at random time points within the following 15 min. ⋯ After noxious stimulation, AAI exceeded the highest recommended value, 25, in 3 cases, whereas BIS did not exceed the recommended threshold, 60, in any of the patients. Response times for BIS and AAI were 44.5 +/- 26 and 47 +/- 31 s, respectively. These results suggest that, at a hypnotic level associated with surgical sevoflurane anesthesia, BIS better displays drug-related alterations in the level of hypnosis than AAI or hemodynamic variables but there is no difference between BIS and AAI in the time to response to a noxious stimulus.
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Anesthesia and analgesia · Oct 2004
ReviewPreoperative evaluation of pediatric surgical patients with multisystem considerations.
Fewer and fewer patients spend time in the hospital in advance of a surgical or interventional procedure requiring anesthesia care. As a result, there is increasing reliance on a thorough preoperative evaluation directed toward identifying anesthetic risks. ⋯ The justification for the cost of this type of program is the savings realized by the decrease in wasted operating room time due to inadequate or incomplete patient preparation. The following is a description of a successful perioperative evaluation and preparation process that has been in place for 7 yr in a major pediatric academic institution.
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Anesthesia and analgesia · Oct 2004
Randomized Controlled Trial Comparative Study Clinical TrialPostoperative pain after abdominal hysterectomy: a double-blind comparison between placebo and local anesthetic infused intraperitoneally.
Abdominal hysterectomy is associated with moderate to severe postoperative pain. We randomly divided 40 patients (ASA status I-II) undergoing elective abdominal hysterectomy into 2 groups: group P received an infusion of normal saline 5 mL/h via a catheter placed intraperitoneally at the end of surgery, and group L received 0.25% levobupivacaine 12.5 mg/h (5 mL/h). Ketobemidone was administered IV via a patient-controlled analgesia pump as a rescue analgesic in all patients. ⋯ A less frequent incidence of postoperative nausea, but not vomiting, was also found during 4-24 h in group L compared with group P (P < 0.025). Total and free plasma concentrations of levobupivacaine were small. We conclude that levobupivacaine used as an infusion intraperitoneally after elective abdominal hysterectomy has significant opioid-sparing effects.
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Anesthesia and analgesia · Oct 2004
Optimal head rotation for internal jugular vein cannulation when relying on external landmarks.
External anatomic landmarks have traditionally been used to approximate the location of the neck blood vessels to optimize central venous cannulation of the internal jugular vein (IJV) while avoiding the common carotid artery (CCA). Head rotation affects vessel orientation, but most landmark techniques do not specify its optimal degree. We simulated catheter insertion via both an anterior and central approach to the right IJV using an ultrasound probe held in the manner of a syringe and needle in 49 volunteers. ⋯ For both approaches, the risk of CCA contact was <10% for head rotations of