Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Clinical TrialThe efficacy of simulated intravascular test dose in sedated patients.
Sedation usually decreases the reliability of subjectively detecting an intravascular test dose, but the efficacies of objective hemodynamic and T-wave criteria remain undetermined. Sixty healthy patients were randomly assigned to receive IV midazolam in 1-mg increments until they were lightly sedated, fentanyl 2 microg/kg followed by incremental midazolam until they were similarly sedated, or no sedative (n = 20 each). Then, normal saline 3 mL was administered IV, followed 4 min later by 1.5% lidocaine 3 mL plus epinephrine 15 microg (1:200,000) in all subjects. Heart rate (HR), systolic blood pressure (SBP) measured by a radial arterial catheter, and lead II of the electrocardiogram were continuously recorded for 4 min after the saline and test dose injections. An IV test dose produced significant increases in HR and SBP and decreases in T-wave amplitude in all subjects. However, the mean maximum increase in HR in patients sedated with midazolam plus fentanyl (31 +/- 14 bpm [mean +/- SD]) was significantly less than in those administered midazolam alone or no sedative (42 +/- 12 and 44 +/- 10 bpm, respectively; P < 0.05). A sensitivity of 100% was obtained on the basis of the traditional HR criterion (positive if > or =20 bpm increase) in patients sedated with midazolam or no sedative, but it was 70% in those with midazolam plus fentanyl (P < 0.05 versus the other two groups). Irrespective of the treatment, sensitivities and specificities of 100% were obtained according to the SBP (positive if > or =15 mm Hg increase) and T-wave (positive if > or =25% decrease in amplitude) criteria. An increase in SBP and a decrease in T-wave amplitude are more reliable than an HR response for detecting accidental intravascular injection of the epinephrine-containing test dose in subjects sedated with midazolam and fentanyl. ⋯ To determine whether an epidural catheter is in a blood vessel, an epidural test dose containing 15 microg epinephrine is used. We found that an increase in systolic blood pressure and a decrease in T-wave amplitude seem to be more reliable than a heart rate change for detecting inadvertent intravascular injection of an epinephrine-containing test dose in patients sedated with midazolam and fentanyl.
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Comparative Study Clinical TrialThe continuous recording of blood pressure in patients undergoing carotid surgery under remifentanil versus sufentanil analgesia.
We compared the hemodynamic stability during carotid endarterectomy of remifentanil with that of sufentanil anesthesia. Fifty-six patients were randomly assigned into Remifentanil (n = 27) or Sufentanil (n = 29) groups. In the Remifentanil group, IV propacetamol (2 g) and morphine (0.1 mg/kg) were infused 30 min before skin closure. In the Sufentanil group, patients received 2 g propacetamol. Beat-to-beat recordings of systolic arterial blood pressure (SBP) and heart rate (HR) were stored on a computer. The maximum and minimum values of BP and HR after induction, at intubation, during the surgical procedure, and after the operation and the coefficients of variation of SBP and HR were used as indices of hemodynamic stability. The coefficients of variation of SBP and HR were similar in both groups during and after surgery. However, at intubation, maximal SBP was higher in the Sufentanil group (P < 0.05). Decreased propofol doses and isoflurane end-tidal concentrations were used in the Remifentanil group. At recovery, a similar profile of SBP and HR was found in both groups. We conclude that intra- and posthemodynamic stability was similar with remifentanil or sufentanil in patients undergoing carotid endarterectomy. However, remifentanil was more effective for blunting the increase in SBP at intubation without increasing the blood pressure-decreasing effect of induction. Intraoperative remifentanil use was associated with a decreased amount of hypnotic drug administered. ⋯ Beat-to-beat recordings of heart rate and blood pressure in patients undergoing carotid surgery revealed that hemodynamic stability was similar with remifentanil or sufentanil anesthesia both during and after surgery. Remifentanil was more effective in limiting the increase in blood pressure associated with intubation without increasing the blood pressure-lowering effect of induction or the blood pressure response to recovery.
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Clinical TrialThe safety of immediate extubation after abdominal aortic surgery: a prospective, randomized trial.
We performed this study to assess the safety of immediate extubation after elective abdominal aortic aneurysm surgery. Consecutive patients were prospectively randomized into two groups after surgery: Group 1 (n = 29) immediate extubation; and Group 2 (n = 21) delayed (at least 4 h) extubation. All patients were assessed by a senior anesthesiologist or intensivist before extubation. The following data were collected: preoperative-demographics, presence of comorbid disease, body mass index, hemoglobin level, heart rate, and blood pressure; intraoperative-duration of surgery and cross-clamping, blood loss, amount of crystalloids, colloids, and blood transfused, temperature at end of procedure, urine output, and complications; and postoperative-time to extubation, scores on the Acute Physiology and Chronic Health Evaluation-II and Therapeutic Intervention Scoring System, total fentanyl dose, and complications. Outcome variables were length of intensive care unit and hospital stay and 28-day mortality. The results showed no significant differences in preoperative or intraoperative variables between the groups, apart from a longer duration of surgery in Group 1 (P = 0.045). Group 2 patients had a significantly higher Therapeutic Intervention Scoring System score (P = 0.04) and required a significantly larger dose of fentanyl (P < 0.001). One patient in Group 2 required reintubation after a cerebrovascular accident. The overall mortality rate was 4% (2 patients in Group 2). There were no significant differences in any of the outcome variables. We conclude that immediate extubation can safely be performed after elective abdominal aortic aneurysm surgery. ⋯ In this prospective randomized study, we compared the outcome of patients undergoing elective aortic abdominal surgery who either were extubated immediately after surgery or after 4 h of stabilization in the intensive care unit. No significant differences were found in the length of intensive care unit or hospital stay, or 28-day mortality between the 2 groups.
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Comparative Study Clinical TrialSelective spinal anesthesia: a comparison of hyperbaric bupivacaine 4 mg versus 6 mg for outpatient knee arthroscopy.
A low-dose (4 mg), low-volume (0.8 mL), low-flow (2 min) technique with hyperbaric bupivacaine toward the dependent side oriented injection and maintenance of the lateral decubitus position for 10 min produced selective spinal anesthesia with rapid recession of motor block and early discharge home.
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Clinical TrialEarly pregnancy does not reduce the C(50) of propofol for loss of consciousness.
Requirements for inhaled anesthetics decrease during pregnancy. There are no published data, however, regarding propofol requirements in these patients. Because propofol is often used for induction of general anesthesia when surgery is necessary in early pregnancy, we investigated whether early pregnancy reduces the requirement of propofol for loss of consciousness using a computer-assisted target-controlled infusion (TCI). Propofol was administered using TCI to provide stable concentrations and to allow equilibration between blood and effect-site (central compartment) concentrations. Randomly selected target concentrations of propofol (1.5-4.5 microg/mL) were administered to both pregnant women (n = 36) who were scheduled for pregnancy termination and nonpregnant women (n = 36) who were scheduled for elective orthopedic or otorhinolaryngologic surgery. The median gestation of the pregnant women was 8 wk (range, 6-12 wk). Venous blood samples for analysis of the serum propofol concentration were taken at 3 min and 8 min after equilibration of the propofol concentration. After a 10-min equilibration period of the predetermined propofol blood concentration, a verbal command to open their eyes was given to the patients twice, accompanied by rubbing of their shoulders. Serum propofol concentrations at which 50% of the patients did not respond to verbal commands (C(50) for loss of consciousness) were determined by logistic regression. There was no significant difference in C(50) +/- SE of propofol for loss of consciousness between the Nonpregnant (2.1 +/- 0.2 microg/mL) and Pregnant (2.0 +/- 0.2 microg/mL) groups. These results indicate that early pregnancy does not decrease the concentration of propofol required for loss of consciousness. ⋯ The C(50) of propofol for loss of consciousness in early pregnancy did not differ from that in nonpregnant women, indicating that there is no need to decrease the propofol concentration for loss of consciousness when inducing general anesthesia for termination of pregnancy.