Anesthesia and analgesia
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Anesthesia and analgesia · Oct 1992
Comparative StudyBuccal pulse oximeter is more accurate than finger pulse oximeter in measuring oxygen saturation.
Although there have been several anecdotal reports of the use of buccal pulse oximeter monitoring (Spo2) when digital Spo2 monitoring cannot be used, there have been no objective evaluations of the accuracy of buccal Spo2 monitoring. The purpose of this study was to systematically compare buccal Spo2 monitoring to both digital Spo2 and arterial O2 saturation monitoring (Sao2) in both generally anesthetized patients in the operating room (n = 31) and critically ill patients in the intensive care unit (n = 23). Buccal Spo2 probes were prepared by taping a malleable metal bar securely over the back of a Nellcor Oxisensor D-25 probe and bending the metal bar and buccal probe firmly around the corner of the patient's mouth. ⋯ We found that buccal Spo2 was higher than finger Spo2 and agreed more closely with Sao2 for both patient groups (98.1% +/- 2.6%, 96.8% +/- 3.5%, 98.5% +/- 2.5%, respectively [mean +/- SD]). The operating room patients had higher buccal and finger Spo2 and Sao2 (99.3% +/- 1.5%, 98.9% +/- 1.4%, 99.5% +/- 0.7%, respectively) than the intensive care unit patients (96.4% +/- 2.9%, 94.1% +/- 3.5%, 96.6% +/- 3.5%, respectively). Although buccal Spo2 monitoring has several disadvantages (i.e., the probe requires preparation, can be more difficult to place, may be less readily accepted in awake patients, and is often mechanically dislodged during airway maneuvers), we conclude that buccal Spo2 monitoring is a more than adequate oximetry alternative when digital Spo2 monitoring is not an option (digits are unavailable or available digits are mechanically interfered with).
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Anesthesia and analgesia · Oct 1992
Randomized Controlled Trial Clinical TrialA new approach to intravenous regional anesthesia.
In an attempt to reduce the dose of local anesthetic during intravenous (IV) regional anesthesia of the upper limb, we combined 100 mg of lidocaine with 0.05 mg of fentanyl and 0.5 mg of pancuronium. The study was designed in a randomized, double-blind fashion to determine the efficacy of this approach in providing analgesia and relaxation during surgery and to evaluate its safety after immediate deflation of the tourniquet following IV drug injection. Eighty unpremedicated patients, ASA physical status I or II, were assigned to the following groups: group A (n = 15) received 100 mg of lidocaine diluted in 40 mL of NaCl IV; groups B-D (n = 15 in each group) received 100 mg of lidocaine diluted in NaCl, with the addition of 0.05 mg of fentanyl (group B) or 0.5 mg of pancuronium (group C), or both (group D) to a total volume in all groups of 40 mL. ⋯ The analgesic effect was more profound in group D compared with groups A-C. In group D, 9 of 15 patients had excellent analgesia. In six patients, pain was experienced at the beginning of surgery, but 5 min thereafter patients remained pain free.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Oct 1992
Intraoperative monitoring of tibialis anterior muscle motor evoked responses to transcranial electrical stimulation during partial neuromuscular blockade.
We studied the feasibility of recording motor evoked responses to transcranial electrical stimulation (tce-MERs) during partial neuromuscular blockade (NMB). In 11 patients, compound muscle action potentials were recorded from the tibialis anterior muscle in response to transcranial electrical stimulation during various levels of vecuronium-induced NMB. The level of NMB was assessed by accelerometry of the adductor pollicis muscle after train-of-four stimulation of the ulnar nerve. ⋯ Before administration of vecuronium, the M-response amplitude was 9.6 +/- 3.6 (mean +/- SD) mV, and the tce-MER amplitude was 1.21 +/- 0.66 mV. Although administration of vecuronium (0.05 mg/kg) resulted in loss of the mechanical adductor pollicis response in 8 of the 11 patients, the M-response and the tce-MER remained recordable. Subsequently, during an infusion of vecuronium, adjusted to maintain one or two mechanical responses to train-of-four stimulation, the average M-response to peroneal nerve stimulation was 5.2 +/- 2.5 mV (53% of the control value), and tce-MER amplitude was 0.59 +/- 0.36 mV (59% of the control value).(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Oct 1992
ReviewCharacteristics and implications of desflurane metabolism and toxicity.
The metabolism of desflurane has been assessed both in animals and humans by measuring the appearance of fluoride metabolites (fluoride ion, nonvolatile organic fluoride, trifluoroacetic acid) in blood and urine. Desflurane administered to rats (either pretreated or not pretreated with phenobarbital or ethanol) for 3.2 MAC-hours and to swine for 5.5 MAC-hours produced fluoride ion levels in blood that were almost indistinguishable from values measured in control animals. In contrast, a significant 17% increase in plasma fluoride ion concentration in swine was detected 4 h after exposure to desflurane. ⋯ Peak serum concentrations averaging 0.38 +/- 0.17 microM trifluoroacetic acid (mean +/- SD) and peak urinary excretion rates averaging 0.169 +/- 0.107 mumol/h were detected in volunteers 24 h after desflurane exposure. Although these increases in trifluoroacetic acid after exposure to desflurane were statistically significant, they are approximately 10-fold less than levels seen after exposure to isoflurane. Desflurane strongly resists biodegradation, and only a small amount is metabolized in animals and humans.