Anesthesia and analgesia
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Anesthesia and analgesia · Aug 2002
Clinical Trial Controlled Clinical TrialThe effect of midazolam on stress levels during simulated emergency medical service transport: a placebo-controlled, dose-response study.
Patients in the emergency medical service (EMS) may have increased endogenous catecholamines because of pain or fear and may benefit from sedation similar to premedication in the hospital. During a simulated EMS scene call, 72 healthy male volunteers were either transported by paramedics from a third-floor apartment through a staircase with subsequent EMS transport with sirens (three stress groups of n = 12; total, n = 36) or asked to sit on a chair for 5 min and lie down on a stretcher for 15 min (three control groups of n = 12; total, n = 36). Catecholamine plasma samples were measured in the respective stress and control groups at baseline and after placebo IV (n = 12) or 25 (n = 12) or 50 (n = 12) microg/kg of midazolam IV throughout the experiment, respectively. Statistical analysis was performed with analysis of variance; P < 0.05 was considered significant. The Placebo Stress versus Control group, but not the 50 microg/kg Stress Midazolam group, had both significantly increased epinephrine (73 +/- 5 pg/mL versus 45 +/- 5 pg/mL; P < 0.001) and norepinephrine (398 +/- 34 pg/mL versus 278 +/- 23 pg/mL; P < 0.01) plasma levels after staircase transport. After EMS transport, the Placebo Stress versus Control group had significantly increased epinephrine (51 +/- 4 pg/mL versus 37 +/- 4 pg/mL; P < 0.05) but not norepinephrine (216 +/- 24 pg/mL versus 237 +/- 18 pg/mL) plasma levels, whereas no significant differences in catecholamine plasma levels occurred between groups after either 25 or 50 microg/kg of midazolam. In conclusion, simulated EMS patients may be subject to more stress during staircase transport than during transport in an EMS vehicle. Titrating sedation with 25 microg/kg of midazolam significantly reduced endogenous catecholamines but not heart rate. ⋯ Simulated emergency medical service patients were more likely to be stressed when being transported by paramedics through a staircase than in an ambulance. Accordingly, it may be beneficial to inject sedative drugs before initiating transport to ensure patient comfort and safety.
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Anesthesia and analgesia · Aug 2002
Randomized Controlled Trial Clinical TrialOral tizanidine, an alpha2-adrenoceptor agonist, reduces the minimum alveolar concentration of sevoflurane in human adults.
Tizanidine, an alpha2-adrenoceptor agonist, has an antinociceptive effect in animals. In humans premedicated with oral tizanidine, the increase in blood pressure associated with laryngoscopy and intubation was attenuated, and the amount of midazolam required for loss of consciousness was significantly reduced. We speculated that the oral administration of tizanidine might reduce the minimum alveolar anesthetic concentration (MAC) of sevoflurane. Fifty-two ASA physical status I-II patients, aged 24-56 yr, were randomly allocated into two groups: a Control group (n = 26) and a Tizanidine group (n = 26). As premedication, the Control group received a placebo, and the Tizanidine group received 4 mg of oral tizanidine 90 min before surgical skin incision. Anesthesia was induced in all patients by using vital capacity rapid inhaled induction with sevoflurane (5%). Loss of consciousness was defined as both the loss of the eyelid reflex and the lack of a response to a verbal command. MAC was determined by a technique adapted from the conventional up-down method for quantal responses. The MAC of sevoflurane was 2.2% +/- 0.2% in the Control group and 1.8% +/- 0.2% in the Tizanidine group (P = 0.0004). The time to loss of consciousness in the Tizanidine group (60.2 +/- 22.5 s) was significantly shorter than that in the Control group (73.7 +/- 26.3 s) (P = 0.03). The oral administration of tizanidine 4 mg successfully reduced the MAC of sevoflurane by 18% in human adults. ⋯ Oral tizanidine (4 mg), an alpha2-adrenoceptor agonist, reduces the minimum alveolar concentration of sevoflurane by 18%.
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Anesthesia and analgesia · Aug 2002
Case ReportsPulmonary artery rupture after attempted removal of a pulmonary artery catheter.
Withdrawal of a pulmonary catheter before initiation of cardiopulmonary bypass may prevent suturing the catheter to the pulmonary trunk and avoid the fatal complication of pulmonary artery rupture.
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Anesthesia and analgesia · Aug 2002
Comparative StudyDistal nerve blocks at the wrist for outpatient carpal tunnel surgery offer intraoperative cardiovascular stability and reduce discharge time.
Carpal tunnel release is often performed as an outpatient procedure. We designed this retrospective study to assess the effect of different anesthesia techniques on intraoperative cardiovascular stability and discharge time. According to the anesthesia technique received, 62 consecutive patients were categorized in Group BIER (IV regional anesthesia), Group BLOCK (distal nerve blocks), and Group GENERAL (general anesthesia). Incidences of intraoperative periods of tachycardia or bradycardia and hyper- or hypotension were studied, as were tourniquet, surgical, operating room, and discharge times. Cardiovascular stability was better achieved in Group BLOCK, as indicated by a significantly smaller incidence of periods of hypertension compared with Group BIER (5% vs 25%) and a significantly less frequent incidence of periods of hypotension compared with Group GENERAL (14% vs 42%). Patients in Group BLOCK spent significantly less time in the hospital after surgery than patients in Group BIER (65 vs 88 min) or patients in Group GENERAL (65 vs 133 min). We conclude that distal nerve blocks for outpatient carpal tunnel surgery are associated with greater intraoperative cardiovascular stability than general anesthesia. After surgery, patients in Group BLOCK could be discharged earlier than patients who received IV regional anesthesia or general anesthesia; this could be related to the superior postoperative analgesia provided by this technique. ⋯ This retrospective analysis of three different anesthetic techniques for ambulatory carpal tunnel surgery shows that nerve blocks performed at the wrist provided excellent intraoperative cardiovascular stability and allowed for earlier discharge.
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Anesthesia and analgesia · Aug 2002
Comparative Study Clinical TrialPerioperative gastric emptying is not a predictor of early postoperative nausea and vomiting in patients undergoing laparoscopic cholecystectomy.
It is not known whether patients with postoperative nausea and vomiting (PONV) have delayed gastric emptying compared with patients without PONV. We compared the perioperative rate of gastric emptying in patients experiencing PONV with the rate in those without PONV immediately after laparoscopic cholecystectomy. Gastric emptying was studied by the acetaminophen method. Acetaminophen is not absorbed from the stomach but is rapidly absorbed from the small intestine, and the rate of gastric emptying therefore determines the rate of absorption of acetaminophen administered into the stomach. Forty patients (ASA physical status I and II) were included in the study. After the induction of anesthesia, a gastric tube was positioned in the stomach and 1.5 g of acetaminophen dissolved in 200 mL of water was administered. Venous blood samples for the determination of serum acetaminophen concentrations were taken before and at 15-min intervals during a period of 180 min after the administration of acetaminophen. Twenty-six patients experienced nausea during the first 4 h postoperatively. The other 14 patients had no nausea. There were no statistically significant differences in the maximal acetaminophen concentration, the time taken to reach the maximal concentration, or the area under the serum acetaminophen concentration time curves from 0 to 60, 0-120, and 0-180 min between the groups of patients with or without PONV. We did not find any relationship between postoperative gastric emptying and PONV, and therefore gastric emptying is not a predictor of PONV. ⋯ The incidence of postoperative nausea and vomiting is frequent after laparoscopic cholecystectomy. This study has shown that perioperative gastric emptying is not a predictor of early postoperative nausea and vomiting in patients undergoing laparoscopic cholecystectomy.