Anesthesiology
-
Spontaneous post-anesthetic tremor that resembles shivering is common during recovery from anesthesia. Risks to postoperative patients include an increase in metabolic rate of up to 400%, hypoxemia, wound dehiscence, dental damage, and disruption of delicate surgical repairs. The etiology of spontaneous post-anesthetic tremor is most commonly attributed to normal thermoregulatory shivering in response to intraoperative hypothermia. ⋯ Two distinct EMG patterns were identified: 1) regular, bursting signals of 5-7 Hz similar to those produced by pathologic clonus in patients with spinal cord transections; and 2) tonic, irregular signals of 5-15 Hz which had poorly defined bursts that did not demonstrate the synchronous 4-8-cycle/min waxing and waning pattern typical of normal shivering. EMG activity occurred most often at expired isoflurane concentrations of 0.1-0.19%, and was not related to rectal temperature. During the later part of recovery when isoflurane concentrations were less than or equal to 0.1%, hypothermic patients frequently demonstrated no clinical or EMG evidence of muscular activity.(ABSTRACT TRUNCATED AT 250 WORDS)
-
Comparative Study Clinical Trial Controlled Clinical Trial
Topical anesthesia with lidocaine aerosol in the control of postoperative pain.
Postoperative pain was assessed in patients undergoing inguinal hernia repair. Ten patients received lidocaine aerosol in the surgical wound before skin closure, ten patients received placebo aerosol devoid of lidocaine, and ten patients were untreated. The lidocaine-treated group had significantly lower pain scores and meperidine requirements during the first postoperative day compared to the control groups. ⋯ Results show that lidocaine aerosol used as topical anesthetic in the surgical wound is simple to use, and results in a long-lasting reduction of pain after a single administration. Moreover, postoperative mobilization is facilitated, and the requirement for postoperative analgesics is reduced. Wound healing was normal, and no adverse reactions to lidocaine were reported.
-
Randomized Controlled Trial Clinical Trial
The thermoregulatory threshold in humans during halothane anesthesia.
Although suppression of thermoregulatory mechanisms by anesthetics is generally assumed, the extent to which thermoregulation is active during general anesthesia is not known. The only thermoregulatory responses available to anesthetized, hypothermic patients are vasoconstriction and non-shivering thermogenesis. To test anesthetic effects on thermoregulation, the authors measured skin-surface temperature gradients (forearm temperature--finger-tip temperature) as an index of cutaneous vasoconstriction in unpremedicated patients anesthetized with 1% halothane and paralyzed with vecuronium during elective, donor nephrectomy. ⋯ These data indicate that active thermoregulation occurs during halothane anesthesia, but that it does not occur until core temperature is approximately equal to 2.5 degrees C lower than normal. In two additional hypothermic patients, increased skin-temperature gradients correlated with decreased perfusion as measured by a laser Doppler technique. Measuring skin-surface temperature gradients is a simple, non-invasive, and quantitative method of determining the thermoregulatory threshold during anesthesia.
-
Comparative Study Clinical Trial
Relative analgesic potency of epidural fentanyl, alfentanil, and morphine in treatment of postoperative pain.
-
The authors investigated the role of alpha 1- and beta-adrenoceptors on the induction of arrhythmias during halothane anesthesia in the dog. The arrhythmogenic doses (ADs) of various combinations of alpha 1- and beta-adrenoceptor agonists were determined in dogs (N = 105) during halothane anesthesia. Isoproterenol (ISP) and phenylephrine (PHE) administered separately failed to induce arrhythmias in doses up to 4 micrograms/kg and 200 micrograms/kg, respectively. ⋯ At a systolic pressure of 150, 160, 170, or 180 mmHg, there was no significant difference between the AD of ISP in the presence of PHE and that in the presence of ANG II. Increasing heart rate by electrical pacing did not replace ISP in the arrhythmogenic interaction between ISP and PHE. The results indicate that both alpha 1- and beta-adrenoceptor agonists are important for producing arrhythmias during halothane anesthesia, and that these agonists synergistically interact on the heart by different mechanisms.