Xenon Provides Faster Emergence from Anesthesia than Does Nitrous Oxide-sevoflurane or Nitrous Oxide-isoflurane 

1997 ◽  
Vol 86 (6) ◽  
pp. 1273-1278 ◽  
Author(s):  
Takahisa Goto ◽  
Hayato Saito ◽  
Masahiro Shinkai ◽  
Yoshinori Nakata ◽  
Fumito Ichinose ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Minimum Alveolar Concentration ◽  
Total Abdominal Hysterectomy ◽  
Abdominal Hysterectomy ◽  
Patient Demographics ◽  
The Mean ◽  
American Society ◽  
End Tidal ◽  
To Receive ◽  
Rapid Emergence

Background Xenon, an inert gas with anesthetic properties (minimum alveolar concentration [MAC] = 71%), has an extremely low blood:gas partition coefficient (0.14). Therefore, we predicted that xenon would provide more rapid emergence from anesthesia than does N2O+isoflurane or N2O+sevoflurane of equivalent MAC. Methods Thirty American Society of Anesthsiologists class I or II patients undergoing total abdominal hysterectomy were randomly assigned to receive 60% xenon, 60% N2O + 0.5% isoflurane, or 60% N2O + 0.70% sevoflurane (all concentrations are end-tidal: n = 10 per group). After placement of an epidural catheter, anesthesia was induced with standardized doses of midazolam, thiopental, and fentanyl. Thirty minutes later, xenon, N2O+isoflurane, or N2O+sevoflurane was started as previously assigned. These regimens were supplemented with epidural anesthesia with mepivacaine so that the mean arterial pressure and heart rate were controlled within 20% of the preoperative values. At the end of operation lasting approximately 2 h, all inhalational anesthetics were discontinued, and the patients were allowed to awaken while breathing spontaneously on an 8 l/min inflow of oxygen. A blinded investigator recorded the time until the patient opened her eyes on command (T1), was judged ready for extubation (T2), could correctly state her name, her date of birth, and the name of the hospital (T3), and could count backward from 10 to 1 in less than 15 s (T4). Results Emergence times from xenon anesthesia were: T1, 3.4 +/- 0.9 min; T2, 3.6 +/- 1 min; T3, 5.2 +/- 1.4 min; and T4, 6.0 +/- 1.6 min (mean +/- SD). These were one half to one third of those from N2O+sevoflurane (T1, 6.0 +/- 1.7 min; T4, 10.5 +/- 2.5 min) or N2O+isoflurane (T1, 7.0 +/- 1.9 min; T4, 14.3 +/- 2.8 min) anesthesia. The three groups did not differ in terms of patient demographics, the duration of anesthesia, the amount of epidural mepivacaine administered, or the postoperative pain rating. No patient could recalls intraoperative events. Conclusions Emergence from xenon anesthesia is two or three times faster than that from equal-MAC N2O+isoflurane or N2O+sevoflurane anesthesia.

Influence of Nitrous Oxide on Minimum Alveolar Concentration of Sevoflurane for Laryngeal Mask Insertion in Children

2003 ◽  
Vol 99 (5) ◽  
pp. 1055-1058 ◽  
Author(s):  
Shinichi Kihara ◽  
Yuichi Yaguchi ◽  
Shinichi Inomata ◽  
Seiji Watanabe ◽  
Joseph R. Brimacombe ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Minimum Alveolar Concentration ◽  
Interaction Coefficient ◽  
Laryngeal Mask ◽  
Inhalational Induction ◽  
Laryngeal Mask Insertion ◽  
American Society ◽  
End Tidal ◽  
American Society Of Anesthesiologists ◽  
To Receive

Background Inhalational induction with sevoflurane and nitrous oxide is frequently used for Laryngeal Mask Airway (LMA; Laryngeal Mask Company, Henley-on-Thames, United Kingdom) insertion in children. The authors determined the influence of nitrous oxide on the minimum alveolar concentration (MAC) of sevoflurane for LMA insertion. Methods One hundred twenty unpremedicated children (age, 1-9 yr; American Society of Anesthesiologists physical status I) were randomly assigned to receive 1 of 15 end-tidal concentrations of nitrous oxide and sevoflurane for inhalational induction via a facemask: 0% nitrous oxide with 1.2, 1.4, 1.6, 1.8, or 2.0% sevoflurane; 33% nitrous oxide with 0.8, 1.0, 1.2, 1.4, or 1.6% sevoflurane; or 67% nitrous oxide with 0.4, 0.6, 0.8, 1.0, or 1.2% sevoflurane. The LMA was inserted after steady state end-tidal anesthetic concentrations had been maintained for 15 min. The response to insertion was recorded by three independent blinded observers. The interaction between nitrous oxide and sevoflurane was determined using logistic regression analysis. Results The MAC of sevoflurane for LMA insertion (95% confidence limit) was 1.57% (1.42-1.72%), and the concentration of sevoflurane required to prevent movement in 95% of children was 1.99% (1.81-2.57%). The addition of 33% and 67% nitrous oxide linearly decreased the MAC of sevoflurane for LMA insertion by 22% and 49%, respectively (P < 0.001). The interaction coefficient between nitrous oxide and sevoflurane did not differ from zero (P = 0.7843), indicating that the relation was additive. Conclusions Nitrous oxide and sevoflurane suppress the responses to LMA insertion in a linear and additive fashion in children.

Recurrence patterns in patients with stage IIIC1 versus IIIC2 endometrial adenocarcinoma.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. e15501-e15501
Author(s):  
Catherine Bevan ◽  
Christa Irene Nagel ◽  
Todd Patrtick Boren ◽  
David Scott Miller ◽  
Siobhan Marie Kehoe ◽  
...  
Keyword(s):  
Endometrial Cancer ◽  
Endometrial Adenocarcinoma ◽  
Total Abdominal Hysterectomy ◽  
Abdominal Hysterectomy ◽  
Distant Recurrence ◽  
Exact Test ◽  
Frontline Treatment ◽  
Recurrence Patterns ◽  
The Mean ◽  
To Receive

e15501 Background: To identify differences in recurrence patterns between stage IIIC1 and IIIC2 endometrial adenocarcinomas. Methods: A retrospective review was performed with IRB approval of all patients treated for stage IIIC1 and IIIC2 endometrial adenocarcinoma at our institution from 1989-2011. Patients were required to have comprehensive surgical staging including total abdominal hysterectomy, bilateral salpingo-ophorectomy, pelvic and paraaortic lymph node dissection. Descriptive statistics were performed using Microsoft Excel 2011 and Fischer’s exact test, Kaplan-Meier analyses were used to compare disease free (DFS) and overall survival (OS). Results: Eighty-seven patients with stage IIIC endometrial adenocarcinoma were identified, of which 69 were evaluable. The mean age was 59 years and the mean follow up was 32 months. There were 31 patients with stage IIIC1 and 38 patients with stage IIIC2 disease. There was no statistical difference in histology between the two groups: 47 endometrioid, 11 papillary serous, and 11 with other types of adenocarcinoma. Patients with stage IIIC1 disease were more likely to receive pelvic radiation (p=0.0004) and patients with IIIC2 disease were more likely to receive chemotherapy (p=0.014). Median DFS was 28.9 months (range 0-112) and 15.0 months (range 0-166) (p=0.017) and median OS was 31.9 months (range 0-134) and 18.0 months (range 0-166) (p=0.061) for the IIIC1 and IIIC2 groups respectively. Seven of 31 (23%) patients with stage IIIC1 disease recurred: 1 (14%) at the vaginal cuff and 6 (86%) distant. The patient who recurred locally was initially treated with chemotherapy alone. Of the 6 patients with distant recurrences only 1 received chemotherapy. Twelve of the 38 (32%) patients with stage IIIC2 experienced a recurrence: 6 (50%) vaginal/pelvic and 6 (50%) distant. There was a difference between the rates of local versus distant recurrence in patients with IIIC1 and IIIC2 endometrial cancer. Conclusions: IIIC1 patients were less likely to receive systemic chemotherapy and more likely to recur distantly. Our findings suggest a role for adjuvant chemotherapy and radiation in the frontline treatment of both IIIC1 and IIIC2 endometrial cancer.

Anesthetic Doses of Sevoflurane To Block Cardiovascular Responses to Incision when Administered with Xenon or Nitrous Oxide 

1999 ◽  
Vol 91 (2) ◽  
pp. 369-373 ◽  
Author(s):  
Yoshinori Nakata ◽  
Takahisa Goto ◽  
Yoshiki Ishiguro ◽  
Katsuo Terui ◽  
Yoshinari Niimi ◽  
...  
Keyword(s):  
Heart Rate ◽  
Nitrous Oxide ◽  
Mean Arterial Pressure ◽  
Minimum Alveolar Concentration ◽  
Cardiovascular Response ◽  
Cardiovascular Responses ◽  
Suppressive Effect ◽  
Skin Incision ◽  
The Mean ◽  
End Tidal

Background The authors' previous study demonstrated that xenon (Xe) and nitrous oxide (N2O) in combination with sevoflurane can attenuate cardiovascular responses to skin incision. To quantitatively evaluate their suppressive effects on cardiovascular responses, the authors compared the MAC-BAR (minimum alveolar concentration that blocks adrenergic or cardiovascular response to incision) values of sevoflurane when administered with Xe or N2O. Methods Forty-three patients received sevoflurane with one of three anesthetics; 1 MAC Xe, 0.7 MAC Xe and 0.7 MAC N2O. The MAC-BAR of sevoflurane was determined in each anesthetic using the "up and down" method. The response was considered positive if the heart rate or mean arterial pressure increased 15% or more. The end-tidal sevoflurane concentration given to the next patient was increased or decreased by 0.3 MAC if the response was positive or negative in the previous patient, respectively. The MAC-BAR was calculated as the mean of four independent cross-over responses. Results The MAC-BAR of sevoflurane, including the contribution of Xe or N2O, was 2.1+/-0.2 MAC and 2.7+/-0.2 MAC when administered with 1 MAC and 0.7 MAC Xe, respectively, and 2.6+/-0.4 MAC when administered with 0.7 MAC N2O (mean +/- SD). Conclusions Although 1 MAC Xe has a more potent suppressive effect on cardiovascular responses to incision than 0.7 MAC Xe or N2O, Xe and N2O have a similar suppressive effect at 0.7 MAC.

Additive Contribution of Nitrous Oxide to Sevoflurane Minimum Alveolar Concentration for Tracheal Intubation in Children 

1999 ◽  
Vol 91 (3) ◽  
pp. 667-667 ◽  
Author(s):  
Hilton D. Swan ◽  
Mark W. Crawford ◽  
Hwee Ling Pua ◽  
Derek Stephens ◽  
Jerrold Lerman
Keyword(s):  
Nitrous Oxide ◽  
Logistic Regression ◽  
Tracheal Intubation ◽  
Logistic Model ◽  
Minimum Alveolar Concentration ◽  
Interaction Coefficient ◽  
Regression Curves ◽  
Additive Contribution ◽  
End Tidal ◽  
To Receive

Background To study the interaction between nitrous oxide and sevoflurane during trachea intubation, the authors determined the minimum alveolar concentration of sevoflurane for tracheal intubation (MAC(TI)) with and without nitrous oxide in children. Methods Seventy-two children aged 1-7 yr were assigned randomly to receive one of three end-tidal concentrations of nitrous oxide and one of four end-tidal concentrations of sevoflurane: 0% nitrous oxide with 2.0, 2.5, 3.0, or 3.5% sevoflurane: 33% nitrous oxide with 1.5, 2.0, 2.5, or 3.0% sevoflurane; or 66% nitrous oxide with 1.0, 1.5, 2.0, or 2.5% sevoflurane. After steady state end-tidal anesthetic concentrations were maintained for at least 10 min, laryngoscopy and intubation were attempted using a straight-blade laryngoscope and an uncuffed tracheal tube. The interaction between nitrous oxide and sevoflurane was investigated using logistic regression analysis of the responses to intubation. Results Logistic regression curves of the probability of no movement in response to intubation in the presence of sevoflurane and 0, 33, and 66% nitrous oxide were parallel. The interaction coefficient between nitrous oxide and sevoflurane did not differ significantly from zero (P = 0.89) and was removed from the logistic model. The MAC(TI) (+/- SE) of sevoflurane was 2.66+/-0.16%, and the concentration of sevoflurane required to prevent movement in 95% of children was 3.54+/-0.25%. Thirty-three percent and 66% nitrous oxide decreased the MAC(TI) of sevoflurane by 18% and 40% (P<0.001), respectively. Conclusions We conclude that nitrous oxide and sevoflurane suppress the responses to tracheal intubation in a linear and additive fashion in children.

scholarly journals Clinical benefits of preemptive oral clonidine versus oral tramadol for abdominal hysterectomy conducted under subarachnoid block with 0.5% hyperbaric bupivacaine: a comparative evaluation

2017 ◽  
Vol 5 (7) ◽  
pp. 3129
Author(s):  
Kumkum Gupta ◽  
Swati Sharma ◽  
Prashant K. Gupta ◽  
Guljeet Kaur ◽  
Vasundra Tyagi ◽  
...  
Keyword(s):  
Muscle Relaxation ◽  
Abdominal Hysterectomy ◽  
Hyperbaric Bupivacaine ◽  
Subarachnoid Block ◽  
Oral Clonidine ◽  
Significant Difference ◽  
Clinical Benefits ◽  
Intraoperative Period ◽  
American Society ◽  
To Receive

Background: Neuraxial techniques possess many benefits for elective abdominal hysterectomy due to profound surgical anesthesia and muscle relaxation. The present study was aimed to compare the clinical benefits of pre-emptive oral clonidine with oral tramadol for abdominal hysterectomy conducted under subarachnoid block with 0.5% hyperbaric bupivacaine.Methods: Sixty adult female patients of American Society of Anaesthesiologists (ASA) physical status I and II, aged 42 to 65 years, were randomized into two groups of 30 patients each to receive either oral clonidine, 100 µg (Group C) or oral tramadol 50 mg tramadol (Group T), 90 min before initiation of subarachnoid block with 3.5 mL of 0.5% hyperbaric bupivacaine. Intraoperative hemodynamic changes, duration of analgesia and incidence of shivering were recorded as primary end points. Drug related effects of pruritus, sedation, nausea, vomiting, and respiratory depression were recorded as secondary outcomes.Results: The onset of sensory and motor block was comparable between the groups but the time to two dermatome regression were prolonged in patients of Group C with statistical significant difference (p=0.05). Duration of analgesia was also enhanced in patients of Group C (268.27±12.18 min versus 223.15±14.31 min in Group T) with statistically highly significant difference (p=0.000). The incidence of shivering was lower in the patients of clonidine group. The heart rate was lower in patients of clonidine throughout intraoperative period and no incidence of bradycardia, hypotension or sedation occurred in any patient.Conclusions: Both drugs showed clinical benefits as pre-emptive oral medication for abdominal hysterectomy conducted under subarachnoid block but oral clonidine (100 µg) proved to be more beneficial.

scholarly journals CLINICAL PROFILE AND MANAGEMENT OPTION OF FIBROID UTERUS PATIENTS OF OBSTETRICS AND GYNAECOLOGY DEPARTMENT OF DMCH, LAHERIASARAI, BIHAR

2020 ◽  
pp. 1-2
Author(s):  
Sangeeta Singh ◽  
Renu Jha ◽  
Seema Seema ◽  
Debarshi Jana
Keyword(s):  
Uterine Fibroids ◽  
Total Abdominal Hysterectomy ◽  
Abdominal Hysterectomy ◽  
Management Options ◽  
Fibroid Uterus ◽  
Number Of Patients ◽  
Study Results ◽  
The Mean ◽  
Benign Tumours ◽  
Symptomatic Uterine Fibroid

Background: Fibroids are the most common benign tumours of smooth muscle cells of uterus in females and typically found during the middle and later reproductive years. As fibroid is an estrogen and progesterone dependent tumour, it gradually decreases in size during starting of menopause. The objective of this presented study was to determine management options among fibroid uterus patients. Methods: 50 number of patients were included in this study those who’s age of 20-55, with symptomatic uterine fibroid and undergone hysterectomy or myomectomy. Postmenopausal, Pregnancy and Asymptomatic fibroid were excluded from this study. Results: The study showed that 52 percent of patient having fibroid uterus were belonged to 31-40 years of age. The mean age was 41.2±6.07. The majority 74% of patients in this study presented with menstrual abnormalities, 40% presented with abdominal lump. Dysmenorrhoea was 26%, 6% patient had primary subfertility and 14% secondary subfertility. Total Abdominal Hysterectomy (TAH) with unilateral salpingo- oophorectomy done in 10% cases, TAH with bilateral salpino-oophorectomy in 22% cases, non descent vaginal hysterectomy in 6% cases, myomectomy done in 20% cases and polypectomy was done in 2% cases. Conclusion: Uterine fibroids are very common in women and frequently in late reproductive and perimenopausal years. It is also a common gynecological problem in our country, which frequently disturbs the lives of woman. Women now have choice of therapies for the treatment of fibroids.

Reduction of the Minimum Alveolar Concentration of Isoflurane by Dexmedetomidine 

1997 ◽  
Vol 86 (5) ◽  
pp. 1055-1060 ◽  
Author(s):  
Riku Aantaa ◽  
Marja-Leena Jaakola ◽  
Antero Kallio ◽  
Jussi Kanto
Keyword(s):  
Minimum Alveolar Concentration ◽  
Study Drug ◽  
Abdominal Hysterectomy ◽  
Skin Incision ◽  
Control Group ◽  
High Dose ◽  
Anesthesia Induction ◽  
Drug Infusion ◽  
Target Plasma Concentration ◽  
End Tidal

Background alpha 2-Adrenergic agonists have been shown to reduce anesthetic requirements of other anesthetics, and they may even act as complete anesthetics by themselves at high doses in animal models. The present study was designed to define the interaction of intravenous infusion of dexmedetomidine, an alpha 2-adrenergic agonist, and isoflurane in patients having surgery by using the minimum alveolar concentration (MAC) of isoflurane as the measure of anesthetic potency. Methods Forty-nine women scheduled for abdominal hysterectomy were randomly allocated to receive either a placebo infusion (n = 16) or a two-stage infusion of dexmedetomidine with target plasma concentration of 0.3 ng/ml (n = 17) or 0.6 ng/ml (n = 16). The study drug infusion was commenced 15 min before induction of anesthesia with thiopental and alfentanil and was continued until skin incision. The end-tidal concentration of isoflurane for each patient was predetermined according to the "up-down" method of Dixon, and it was maintained for at least 15 min before the patient's response to skin incision was assessed. Results The MAC of isoflurane was 0.85% end-tidal in the control group, 0.55% end-tidal with the low dose of dexmedetomidine, and 0.45% end-tidal with the high dose of dexmedetomidine. Conclusions The MAC of isoflurane in the control group was lower than that reported previously in similar patients having surgery, probably due to anesthesia induction with thiopental and alfentanil. Nevertheless, with the high dose of dexmedetomidine, the MAC of isoflurane was still 47% less than that without dexmedetomidine.

scholarly journals Uterine Myoma: A Profile of Nepalese women

1970 ◽  
Vol 1 (2) ◽  
pp. 47-50
Author(s):  
Pramila Pradhan ◽  
Nitish Acharya ◽  
Binit Kharel ◽  
Manoj Manjin
Keyword(s):  
Abdominal Mass ◽  
College Teaching ◽  
Total Abdominal Hysterectomy ◽  
Abdominal Hysterectomy ◽  
Early Marriage ◽  
Early Completion ◽  
Medical College ◽  
Underlying Risk Factor ◽  
The Mean ◽  
Myoma Uteri

Objectives: To determine the most common age and parity for the development of myoma uteri. To find out any relation between age of the last child and the development of myoma uteri. To determine the treatment protocal and outcome of treatment. Materials/methods: This study was carried out at Nepal Medical College Teaching Hospital from Jan 2001 to 31st June 2006. All cases of myoma uteri admitted in Gynaecological ward was included.. Histological evidence of myoma confirmed the diagnosis. Age, parity and age of the last child, clinical features, surgical procedures and outcome of surgery were considered. Results: A total of 137 cases of myoma uteri was operated during five and half years period. This represented 38.5 %of all abdominal hysterectomy performed during the same period. The mean age was 43.3 years with median parity at 1-3 and the mean age of last child at 12years. Excessive menstrual bleeding 73.0%, abdominal mass and pain 58.4%, dysmenorrhea 18.2% and infertility 7.3% were the common symptoms. Total abdominal hysterectomy was the mainstay of treatment. Patients were happy with the treatment specially those with severe and multiple symptoms Postoperative complications were not significant. There was one death due to pulmonary embolism who had mesothelioma of pleura diagnosed by pleural biopsy before operation. Conclusion: Early marriage and early completion of the family is the social trend in Nepalese society. Myoma is common in 4th-5th decade of life in multi parity with the age of last child around 12years. This long standing secondary infertility may be an underlying risk factor in the development of myoma uteri.   doi:10.3126/njog.v1i2.2397 N. J. Obstet. Gynaecol Vol. 1, No. 2, p. 47-50 Nov-Dec 2006   

Fentanyl Augments the Blockade of the Sympathetic Response to Incision (MAC-BAR) Produced by Desflurane and Isoflurane 

1998 ◽  
Vol 88 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Malcolm Daniel ◽  
Richard B. Weiskopf ◽  
Mariam Noorani ◽  
Edmond I. Eger
Keyword(s):  
Nitrous Oxide ◽  
Cardiovascular Response ◽  
Dependent Manner ◽  
Surgical Incision ◽  
Arterial Blood ◽  
Adrenergic Response ◽  
The Mean ◽  
End Tidal ◽  
Inhaled Anesthetic ◽  
Dose Dependent

Background Heart rate (HR) or mean arterial blood pressure (MAP) may increase in response to incision despite the absence of a motor response. The authors hypothesized that the MAC-BAR (minimum alveolar concentration of an anesthetic that blocks adrenergic response to incision) for isoflurane would exceed that for desflurane, and that fentanyl would decrease the MAC-BAR for each anesthetic in a dose-dependent manner. Methods Seventy-one patients were randomly allocated to one of six groups: desflurane or isoflurane without fentanyl or with 1.5 or 3 microg/kg fentanyl given intravenously 5 min before surgical incision. Anesthesia was induced with 2 mg/kg propofol given intravenously, and tracheal intubation facilitated with 0.1 mg/kg given intravenously. The first patient in each group received 1 MAC (end-tidal) of the inhaled anesthetic in 60% nitrous oxide (0.55 MAC), balance oxygen, maintained for at least 10 min before incision. The response was considered positive if the HR or MAP increased 15% or more. If the response was positive, the end-tidal concentration given to the next patient was 0.3 MAC greater; if the response was negative, the end-tidal concentration was 0.3 MAC less. The MAC-BAR level was calculated as the mean of four independent cross-over responses in each group. Results Desflurane and isoflurane anesthesia with 60% nitrous oxide did not change HR (P > 0.05) and decreased MAP (P < 0.05) before incision. Plasma epinephrine and norepinephrine concentrations after anesthesia and before incision were normal in all groups. The MAC-BAR level, without fentanyl, did not differ (P > 0.05) between desflurane (1.30 +/- 0.34 MAC [mean +/- SD]) and isoflurane (1.30 +/- 0.18 MAC). Fentanyl given at 1.5 microg/kg intravenously equivalently (P > 0.05) reduced the MAC-BAR for desflurane (to 0.40 +/- 0.18 MAC; P < 0.05) and isoflurane (to 0.55 +/- 0.00 MAC; P < 0.05), but a further increase in fentanyl to 3 microg/kg caused no greater decrease in the MAC-BAR for desflurane (0.48 +/- 0.16 MAC) and isoflurane (0.40 +/- 0.30 MAC). Conclusions Clinically attainable doses of desflurane and isoflurane, in 60% nitrous oxide (0.55 MAC), block the cardiovascular response to surgical incision at 1.3 MAC. Fentanyl given at 1.5 microg/kg decreases the MAC-BAR for each agent with no further decrease produced by 3 microg/kg fentanyl.

Effects of Two Target-controlled Concentrations (1 and 3 ng/ml) of Remifentanil on MACBARof Sevoflurane

2004 ◽  
Vol 100 (2) ◽  
pp. 255-259 ◽  
Author(s):  
Andrea Albertin ◽  
Andrea Casati ◽  
Piercarlo Bergonzi ◽  
Greta Fano ◽  
Giorgio Torri
Keyword(s):  
Nitrous Oxide ◽  
Skin Incision ◽  
Double Blind Study ◽  
Double Blind ◽  
Surgical Incision ◽  
Arterial Blood ◽  
Sequential Allocation ◽  
Sympathetic Responses ◽  
American Society ◽  
End Tidal

Background The aim of this prospective, randomized, double-blind study was to determine the effects of two different target-controlled concentrations of remifentanil (1 and 3 ng/ml) on the sevoflurane requirement for blunting sympathetic responses after surgical incision (MACBAR). Methods Seventy-four patients aged 20-50 yr, with American Society of Anesthesiologists physical status I, were anesthetized with propofol, cisatracurium, and sevoflurane with a mixture of 60% nitrous oxide in oxygen. Then, patients were randomly allocated to receive no remifentanil infusion (n = 27) or a target-controlled plasma concentration of 1 ng/ml (n = 27) or 3 ng/ml remifentanil (n = 20). Sympathetic responses to surgical incision (presence or absence of an increase in either heart rate or mean arterial blood pressure of 15% or more above the mean of the values measured during the 2 min before skin incision) were determined after a 20-min period of stable end-tidal sevoflurane and target-controlled remifentanil concentrations. Predetermined end-tidal sevoflurane concentrations and the MACBAR for each group were determined using an up-and-down sequential-allocation technique. Results The MACBAR of sevoflurane was higher in the group receiving no remifentanil (2.8% [95% confidence interval: 2.5-3.0%]) as compared with patients of the groups receiving 1 ng/ml (1.1% [0.9-1.3%]; P = 0.012) and 3 ng/ml remifentanil (0.2% [0.1-0.3%]; P = 0.006). When considering a minimum anesthetic concentration (MAC) value in this age population and the contribution of 60% nitrous oxide (0.55 MAC), the combined MACBAR values, expressed as multiples of the MAC, were 1.95 MAC, 1.1 MAC, and 0.68 MAC, in the three groups, respectively. Conclusion A target-controlled concentration of 1 ng/ml remifentanil results in a 60% decrease in the MACBAR of sevoflurane combined with 60% nitrous oxide. Increasing the target concentration of remifentanil to 3 ng/ml produces a further 30% decrease in the MACBAR values of sevoflurane.

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