Anesthesiology
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Randomized Controlled Trial Clinical Trial
Chloroprocaine antagonism of epidural opioid analgesia: a receptor-specific phenomenon?
Sixty healthy patients scheduled for elective cesarean delivery under epidural anesthesia were randomized to receive either lidocaine or 2-chloroprocaine as the primary local anesthetic agent. When patients first complained of postoperative pain in the recovery room, they were given either fentanyl 50 micrograms or butorphanol 2 mg, epidurally, in a randomized, blinded fashion. Postoperative analgesia, quantitated on a visual analogue scale, as well as time elapsed until first request for supplemental opioid, did not differ for patients receiving butorphanol after either 2-chloroprocaine or lidocaine anesthesia. ⋯ We conclude that 2 mg of butorphanol epidurally provides approximately 2 to 3 h of effective analgesia after cesarean delivery with either lidocaine or 2-chloroprocaine anesthesia. Epidural fentanyl seems to be antagonized when 2-chloroprocaine, but not lidocaine, is used as the primary local anesthetic agent. We suggest a possible mu-receptor-specific etiology for this effect.
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To determine the incidence and duration of hypoxemia in the postanesthesia care unit (PACU), 200 patients were investigated in a single-blind observer study. The number of unrecognized hypoxemic episodes, as well as risk factors and possible association between hypoxemia and postoperative morbidity, were studied. Oxygenation was monitored continuously with a pulse oximeter. ⋯ Patients who had undergone regional anesthesia had a lower risk of hypoxemia (P less than 0.0002). The occurrence of hypoxemia in the PACU could not be correlated to postoperative morbidity. We conclude that hypoxemic episodes in our PACU are common and that the routine use of supplemental oxygen combined with normal clinical surveillance did not prevent hypoxemic episodes.
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Randomized Controlled Trial Clinical Trial
Does perioperative tactile evaluation of the train-of-four response influence the frequency of postoperative residual neuromuscular blockade?
The authors conducted a randomized controlled clinical trial to evaluate the usefulness of perioperative manual evaluation of the response to train-of-four (TOF) nerve stimulation. A total of 80 patients were divided into four groups of 20 each. For two groups (one given vecuronium and one pancuronium), the anesthetists assessed the degree of neuromuscular blockade during operation and during recovery from neuromuscular blockade by manual evaluation of the response to TOF nerve stimulation. ⋯ The median (and range of) TOF ratios recorded in the recovery room were 0.75 (0.33-0.96) and 0.79 (0.10-0.97) in the vecuronium groups monitored with and without a nerve stimulator, respectively. These ratios were significantly higher than those found in the pancuronium groups, which wre 0.66 (0.06-0.90) and 0.63 (0.29-0.95), respectively. However, no difference was found between the vecuronium and pancuronium groups in the number of patients showing clinical signs of residual neuromuscular blockade, as evaluated by the 5-s head-lift test.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Clinical Trial
High thoracic segmental epidural anesthesia diminishes sympathetic outflow to the legs, despite restriction of sensory blockade to the upper thorax.
To evaluate whether, after high thoracic segmental epidural anesthesia, sympathetic blockade spreads caudally beyond sensory blockade, we assessed regional skin temperatures by infrared telethermometry in 53 nonpremedicated patients at constant ambient temperature. Either bupivacaine (4.2 ml, 0.75%, n = 10) or an equal volume of saline (placebo, n = 10) was injected at the C7-T2 epidural space in a randomized double-blinded fashion. ⋯ Midthoracic injection also increased significantly skin temperature on the foot (great toe: +4.0 degrees C +/- 4.9; little toe: +3.6 degrees C +/- 4.8) but not on the hand. In contrast, with lumbar epidural anesthesia, skin temperature increased significantly on the foot (great toe: +8.5 degrees C +/- 2.5; little toe: +8.6 degrees C +/- 2.8) but decreased significantly on the hand (thumb: -3.1 degrees C +/- 2.1; digit 5: -2.8 degrees C +/- 2.5).(ABSTRACT TRUNCATED AT 250 WORDS)