Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2000
The accuracy and precision of body temperature monitoring methods during regional and general anesthesia.
We tested the hypotheses that accuracy and precision of available temperature monitoring methods are different between spinal anesthesia (SA) and general anesthesia (GA), and that patients receiving SA are at equal risk for hypothermia as those receiving GA. Patients scheduled for radical retropubic prostatectomy were enrolled. Either GA (n = 16) or SA (n = 16) was given according to patient and clinician preference. Temperatures were monitored with thermocouple probes at the tympanic membrane, axilla, rectum, and forehead skin surface. Tympanic temperatures were also measured with an infrared device, and forehead skin temperatures were monitored with two brands of liquid crystal thermometer strips. Accuracy and precision of these monitoring methods were determined by using tympanic membrane temperature, measured by thermocouple, as the reference core temperature (T(c)). At the end of surgery, T(c) was similar between SA (35.0 +/- 0.1 degrees C) and GA (35.2 +/- 0.1 degrees C) (P = 0.44). Accuracy and precision of each temperature monitoring method were similar between SA and GA. Rectal temperature monitoring offered the greatest combination of accuracy and precision. All other methods underestimated T(c). These findings suggest that patients receiving SA or GA are at equal and significant risk for hypothermia, and should have their temperatures carefully monitored, recognizing that most monitoring methods underestimate T(c). ⋯ Body temperature should be monitored during spinal anesthesia because patients are at significant risk for hypothermia. Rectal temperature is a valid method of measuring core temperature, whereas other methods tend to underestimate true core temperature.
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Anesthesia and analgesia · Apr 2000
Safe and efficient emergency transvenous ventricular pacing via the right supraclavicular route.
Infraclavicular and internal jugular central venous access are techniques commonly used for temporary transvenous pacing. However, the procedure still has a considerable complication rate, with a high risk/benefit ratio because of insertion difficulties and pacemaker malfunction. To enlarge the spectrum of alternative access sites, we prospectively evaluated the right supraclavicular route to the subclavian/innominate vein for emergency ventricular pacing with a transvenous flow-directed pacemaker as a bedside procedure. For 19 mo, 17 consecutive patients with symptomatic bradycardia, cardiac arrest, or torsade de pointes requiring immediate bedside transvenous pacing were enrolled in the study. The success rate, insertional complications, pacemaker performance, and patients' outcomes were recorded. Supraclavicular venipuncture was successful in all patients, in 16 of 17 at the first attempt. Adequate ventricular pacing was achieved within 1 to 5 min (median, 2 min) after venipuncture and within 10 s to 4 min (median, 30 s) after lead insertion (
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Anesthesia and analgesia · Apr 2000
Randomized Controlled Trial Multicenter Study Comparative Study Clinical TrialA randomized, double-blinded study of remifentanil versus fentanyl for tonsillectomy and adenoidectomy surgery in pediatric ambulatory surgical patients.
We compared, in a double-blinded manner, the anesthetic maintenance and recovery properties of remifentanil with a clinically comparable fentanyl-based anesthetic technique in pediatric ambulatory surgical patients. Anesthesia was induced with either halothane or sevoflurane and nitrous oxide and oxygen. Patients were randomized (computer generated) to receive either remifentanil or fentanyl in a blinded syringe with nitrous oxide and oxygen in one of four possibilities: halothane/remifentanil, halothane/fentanyl, sevoflurane/remifentanil or sevoflurane/fentanyl. In patients receiving remifentanil, a placebo bolus was administered, and a continuous infusion (0.25 microg. kg(-1). min(-1)) was begun. In patients receiving fentanyl, a bolus (2 microg/kg) was administered followed by a placebo continuous infusion. The time from discontinuation of the anesthetic to extubation, discharge from the postanesthesia care unit (PACU), and discharge to home, as well as pain scores, were assessed by a blinded nurse observer. Systolic blood pressure and heart rate were noted at selected times, and adverse events were recorded. Remifentanil provided faster extubation times and higher pain-discomfort scores. PACU and hospital discharge times were similar. There were no statistical differences among the groups for adverse events. There were statistically, but not clinically, significant differences in hemodynamic variables. We noted that continuous infusions of remifentanil were intraoperatively as effective as bolus fentanyl. Although patients could be tracheally extubated earlier with remifentanil, this did not translate to earlier PACU or hospital discharge times. In addition, remifentanil was associated with higher postoperative pain scores. The frequent incidence of postoperative pain observed in the postoperative recovery room suggests that better intraoperative prophylactic analgesic regimens for postoperative pain control are necessary to optimize remifentanil's use as an anesthetic for children. ⋯ This is a study designed to examine the efficacy and safety of a short-acting opioid, remifentanil, when used in pediatric patients. The frequent incidence of postoperative pain observed in the postoperative recovery room suggests that better intraoperative prophylactic analgesic regimens for postoperative pain control are necessary to optimize remifentanil's use as an anesthetic for children.
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Anesthesia and analgesia · Apr 2000
Randomized Controlled Trial Clinical TrialThe hemodynamic and adrenergic effects of perioperative dexmedetomidine infusion after vascular surgery.
We tested dexmedetomidine, an alpha(2) agonist that decreases heart rate, blood pressure, and plasma norepinephrine concentration, for its ability to attenuate stress responses during emergence from anesthesia after major vascular operations. Patients scheduled for vascular surgery received either dexmedetomidine (n = 22) or placebo (n = 19) IV beginning 20 min before the induction of anesthesia and continuing until 48 h after the end of surgery. All patients received standardized anesthesia. Heart rate and arterial blood pressure were kept within predetermined limits by varying anesthetic level and using vasoactive medications. Heart rate, arterial blood pressure, and inhaled anesthetic concentration were monitored continuously; additional measurements included plasma and urine catecholamines. During emergence from anesthesia, heart rate was slower with dexmedetomidine (73 +/- 11 bpm) than placebo (83 +/- 20 bpm) (P = 0.006), and the percentage of time the heart rate was within the predetermined hemodynamic limits was more frequent with dexmedetomidine (P < 0.05). Plasma norepinephrine levels increased only in the placebo group and were significantly lower for the dexmedetomidine group during the immediate postoperative period (P = 0.0002). We conclude that dexmedetomidine attenuates increases in heart rate and plasma norepinephrine concentrations during emergence from anesthesia. ⋯ The alpha(2) agonist, dexmedetomidine, attenuates increases in heart rate and plasma norepinephrine concentrations during emergence from anesthesia in vascular surgery patients.
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Anesthesia and analgesia · Apr 2000
Opioid substitution to improve the effectiveness of chronic noncancer pain control: a chart review.
We evaluated the efficacy and tolerability of opioids in the long-term management of chronic noncancer pain. This retrospective chart review included 86 outpatients who started receiving, between 1994 and 1998, long-acting opioids. For each patient, the number of different opioids used and the efficacy and tolerability of each opioid prescribed were noted. During a mean follow-up of 8.8 +/- 6.3 mo, the number of opioids used by each patient was 2.3 +/- 1.4. Patient diagnoses were: back pain (31), neuropathy (20), joint pain (13), visceral pain (7), reflex sympathetic dystrophy (7), headache (5), fibromyalgia (3). The first opioid prescribed was effective for 36% of patients, was stopped because of side effects in 30%, and was stopped for ineffectiveness in 34%. Of the remaining patients, the second opioid prescribed after the failure of the first was effective in 31%, the third in 40%, the fourth in 56%, and the fifth in 14%. There was one case of addiction and no case of tolerance. We conclude that if it is necessary to change the opioid prescription because of intolerable side effects or ineffectiveness, the cumulative percentage of efficacy increases with each new opioid tested. Failure of one opioid cannot predict the patient's response to another. ⋯ This study showed that if a patient receiving chronic opioid therapy experiences an intolerable side effect or if the drug is ineffective, changing to a different opioid may result in a lessening or elimination of the side effect and/or improved analgesia.