Anesthesia and analgesia
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Anesthesia and analgesia · Nov 1993
Randomized Controlled Trial Comparative Study Clinical TrialExcitatory effects and electroencephalographic correlation of etomidate, thiopental, methohexital, and propofol.
Excitatory movements have been observed during induction of anesthesia with etomidate, thiopental, methohexital, and propofol. We studied the frequency of these excitatory effects and correlated movements with electroencephalographic (EEG) findings in 67 unpremedicated patients (mean age 66.1 yr, range 45-82 yr). Excitatory effects, including myoclonus, tremor, and dystonic posturing, occurred in 86.6% of patients receiving etomidate; 69.2% of the patient responses were myoclonic. ⋯ In most patients, the excitatory movements were coincident with the early slow phase of the EEG which corresponds to the beginning of deep anesthesia. We conclude that perhaps caution should be exercised when administering etomidate to patients with a history of seizures as the myoclonic activity is associated with seizure activity. The incidence of excitatory movements after administration of propofol is very low.
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Anesthesia and analgesia · Nov 1993
Randomized Controlled Trial Comparative Study Clinical TrialEpidural anesthesia for labor in an ambulatory patient.
The effectiveness of two epidural analgesic regimens on the ability to ambulate was compared in women in labor by a prospective, randomized, double-blind design. One group of patients received epidural fentanyl, a 75-micrograms bolus and an infusion of fentanyl 2.5 micrograms/mL at 15 mL/h (FENT, n = 53). A second group received ultra low-dose bupivacaine (0.04%), epinephrine (1.7 micrograms/mL), and fentanyl (1.7 micrograms/mL) (BEF, n = 77), a 15-mL bolus followed by an infusion at 15 mL/h. ⋯ Neither problem occurred in FENT patients. Neonatal outcome was similar in both groups. Approximately 70% of women receiving epidural analgesia with fentanyl or ultra low-dose bupivacaine, epinephrine, and fentanyl may ambulate safely during labor.
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Anesthesia and analgesia · Nov 1993
Randomized Controlled Trial Clinical TrialCerebral awakening concentration of sevoflurane and isoflurane predicted during slow and fast alveolar washout.
We studied 49 patients of ASA physical status I to determine cerebral anesthetic concentration on awakening calculated with end-tidal anesthetic concentration, when the end-tidal concentration decreased spontaneously. We also attempted to explain the difference in the average of the bracketing alveolar anesthetic concentration that allows and prevents the response to verbal command during recovery from anesthesia (MAC-Awake) between slow and fast alveolar washout by comparing the cerebral anesthetic concentrations with MAC-Awake determined by fast and slow washout. Slow washout was obtained by decreasing anesthetic concentrations in predetermined steps of 15 min, assuming equilibration between brain and alveolar partial pressures. ⋯ MAC-Awake values obtained by fast washout (0.22 +/- 0.07 MAC for sevoflurane, 0.22 +/- 0.05 MAC for isoflurane) were significantly smaller than those obtained by slow washout. Anesthetic concentrations in the brain at first eye opening calculated with end-tidal concentrations during fast alveolar washout (0.34 +/- 0.08 MAC for sevoflurane, 0.30 +/- 0.08 MAC for isoflurane) were nearly equal to MAC-Awake obtained by slow alveolar washout. The difference in MAC-Awake between fast and slow alveolar washout could be explained by arterial-to-cerebral and end-tidal-to-arterial anesthetic differences.
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Anesthesia and analgesia · Nov 1993
Effects of isoflurane, fentanyl, or thiopental anesthesia on regional cerebral blood flow and brain surface PO2 in the presence of a focal lesion in rabbits.
These studies were conducted to determine the effect of anesthetic drugs on tissue perfusion and O2 supply in the brain with focal cerebral edema. Using an open cranium preparation, we studied the effects of isoflurane (I; 1 minimum alveolar anesthetic concentration), of fentanyl (F; 0.5-1 microgram.kg-1 x min-1), or of thiopental (T; 32.5 mg.kg-1 x h-1) on regional cerebral blood flow (rCBF) and regional brain tissue PO2 in albino rabbits (n = 6 per group) with a focal brain lesion (cold injury). The doses of anesthetics were sufficient to suppress nociception. rCBF (H2 clearance) and tissue PO2 (multiwire surface electrode) were studied adjacent to and distant from the lesion. ⋯ The heterogeneity of the tissue PO2 in fentanyl anesthesia, as well as the increased frequency of hypoxic PO2 values with thiopental, might have resulted from microcirculatory disturbances. Thus, although isoflurane seemed to facilitate hyperemia with an increased O2 supply to the brain, fentanyl tended to induce the opposite response. Although these properties suggest the potential to manipulate perfusion and O2 supply in cerebral ischemia or hyperemia after head injury, the effects of such measures on intracranial pressure, neurologic status, and outcome have yet to be proven.
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Anesthesia and analgesia · Nov 1993
Randomized Controlled Trial Clinical TrialEstablishing intravenous access: a study of local anesthetic efficacy.
We performed a double-blind, randomized, prospective study to determine the local anesthetic that provided the best analgesia for insertion of an 18-gauge intravenous (i.v.) catheter and to determine whether alkalinization of lidocaine decreases the pain of intradermal injection. There were 280 healthy adult patients assigned randomly to seven different groups: benzyl alcohol 0.9% in normal saline, 2-chloroprocaine 3%, lidocaine 1%, lidocaine 1% with preservative, alkalinized lidocaine 1% with preservative, normal saline, and a control group that received i.v. catheter placement without previous drug injection. A 10-cm visual analog pain scale (VAPS) was used to obtain pain scores after pre-i.v. drug injection and after iv catheter insertion. ⋯ We conclude that alkalinized lidocaine decreased the pain associated with its injection. Alkalinized lidocaine was the best local anesthetic for i.v. catheter placement. Benzyl alcohol in normal saline was also effective.