Anesthesia and analgesia
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Anesthesia and analgesia · May 1995
Randomized Controlled Trial Clinical TrialThe hemodynamic responses to an intravenous test dose in vascular surgical patients.
The study was designed to investigate the hemodynamic responses to intravenous (IV) injections of various epidural test doses in vascular surgical patients to determine whether previously established criteria in healthier populations were valid in this inherently sicker population. A double-blind, prospective randomized study was performed on 50 patients, not receiving beta-adrenergic antagonists, presenting for vascular surgery and requiring an arterial line. Patients were randomly assigned to receive a 3-mL injection of one of five solutions, either saline (Group 1), lidocaine 45 mg (Group 2), lidocaine 45 mg and epinephrine 5 micrograms (Group 3), lidocaine 45 mg and epinephrine 10 micrograms (Group 4), or lidocaine 45 mg and epinephrine 15 micrograms (Group 5). ⋯ The mean increase in HR and SBP within Group 5 was 17.0 +/- 5.9 bpm and 31.0 +/- 10.5 mm Hg, respectively. No differences were found between groups for time to maximum change for HR and SBP which for Group 5 were 64.5 +/- 37.4 s and 90.0 +/- 56.7 s, respectively. To achieve 100% sensitivity and specificity for HR increase, the criterion established was > or = 9 bpm.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · May 1995
Randomized Controlled Trial Clinical TrialArterial and jugular venous bulb blood propofol concentrations during induction of anesthesia.
The aim of this study was to show that blood propofol concentrations at loss of consciousness vary with the rate of administration. Eighteen patients were allocated to receive a propofol infusion at 6 or 12 mg.kg-1.h-1 (approximately 8 and 15 mg/min) for induction of anesthesia. Propofol concentrations were analyzed from simultaneous arterial and jugular bulb venous blood samples. ⋯ There were no significant differences between the groups in the area between the arterial and venous time concentration curves from start of infusion to loss of consciousness (3.14 and 3.05 micrograms.mL-1.min-1). This study confirms that a target blood concentration of propofol cannot be identified with loss of consciousness under nonsteady state conditions. Both arterial and venous blood propofol concentrations at loss of consciousness depend on the rate of administration.
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Anesthesia and analgesia · May 1995
Randomized Controlled Trial Comparative Study Clinical TrialThe incidence of gastroesophageal reflux with the laryngeal mask: a comparison with the face mask using esophageal lumen pH electrodes.
To test the hypothesis that the laryngeal mask airway (LMA) predisposes patients to gastroesophageal reflux, we randomly assigned 55 patients having elective surgery to receive standardized anesthesia with the LMA or with conventional face mask (FM) plus airway. A pH-sensitive probe with two electrodes, 10 cm apart, was passed nasally into the esophagus 1 h before induction of anesthesia, and recordings were made continuously until 30 min after surgery. At the distal electrode, 30 cm from the anterior nares, there was a significant difference in the incidence of reflux: 53.6% with the LMA versus 22.2% with the FM (P < 0.05). ⋯ Reflux events continued in the postanesthesia care unit (PACU) in both groups with no significant difference between groups. There was no clinical evidence of aspiration of gastric contents in either group. Use of the LMA appears to result in increased reflux to the level of the mid to upper esophagus, and is associated with a more frequent incidence of multiple reflux events than use of the FM.
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Anesthesia and analgesia · May 1995
Histamine concentrations and hemodynamic responses after remifentanil.
Remifentanil is a new potent opioid analgesic that undergoes rapid esterase metabolism. The purpose of this study was to investigate hemodynamic responses to 2-30 micrograms/kg remifentanil (escalating doses) injected as a bolus over 1 min during general anesthesia. ⋯ Arterial blood was taken for histamine determinations before drug administration and then at 1, 3, and 5 min after drug administration. Administration of remifentanil was associated with a reduction in systolic blood pressure from 134 +/- 18 to 91 +/- 16 mm Hg and heart rate from 99 +/- 20 to 69 +/- 21 bpm and was not associated with alterations in histamine concentration.