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.

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.

scholarly journals Comparative clinical study of the effect of oral clonidine premedication on intraoperative haemodynamics in the patients undergoing laparoscopic cholecystectomy

2017 ◽  
Vol 4 (3) ◽  
pp. 950
Author(s):  
Deepti M. Kotwani ◽  
Manish B. Kotwani ◽  
Beena Kamdar
Keyword(s):  
Laparoscopic Cholecystectomy ◽  
Clinical Study ◽  
Study Drug ◽  
Study Groups ◽  
Skin Incision ◽  
Control Group ◽  
Study Drug Administration ◽  
Oral Clonidine ◽  
Comparative Clinical Study ◽  
Induction Of Anaesthesia

Background: Pneumoperitoneum created during laparoscopy results in patho-physiologic changes, especially in the cardiovascular system. Clonidine diminishes stress response by reducing circulating catecholamines and hence increases perioperative circulatory stability in patients undergoing laparoscopic surgeries. This comparative clinical study was planned compare with controls the effects of oral clonidine premedication (150 micrograms) on the intraoperative haemodynamics during laparoscopic cholecystectomy.Methods: Sixty adult patients between 15-50 years, scheduled for laparoscopic cholecystectomy under general anaesthesia were enrolled in the study. The patients were randomly assigned to two study groups of 30 patients each, Group CL: received oral clonidine (150 microgram) 90 minutes before induction of anaesthesia and Group C: received placebo. Anaesthetic technique was same for both the study groups. Hemodynamic variables (Heart rate, systolic (SBP), diastolic (DBP), mean arterial pressure (MAP), and EtCO2 were recorded at specific times - baseline; 90 minutes following study drug administration; induction of anaesthesia; 5 and 10 minutes following intubation; At skin incision; after creation of CO2 pneumoperitoneum and every 15 minutes thereafter till end of surgery; after desufflation; 5 minutes following extubation.Results: Patients in clonidine group had lower HR, SBP and DBP values as compared to control group at all points of time after giving the study drug (P <0.05). Percent change from baseline in HR and Blood pressure at different points of time was significantly high in control group than in clonidine group.Conclusions: Oral clonidine premedication (150 micrograms) is safe and provides perioperative hemodynamic stability in ASA I and II patients undergoing laparoscopic cholecystectomy, and hence can be recommended as a routine premedication for laparoscopic procedures.

Effects of anesthetic agents on systemic critical O2 delivery

1991 ◽  
Vol 71 (1) ◽  
pp. 83-93 ◽  
Author(s):  
P. Van der Linden ◽  
E. Gilbart ◽  
E. Engelman ◽  
D. Schmartz ◽  
J. L. Vincent
Keyword(s):  
Low Dose ◽  
Control Group ◽  
High Dose ◽  
Vascular Effects ◽  
Anesthetic Agents ◽  
O2 Extraction ◽  
End Tidal ◽  
O2 Delivery ◽  
Dose Dependent ◽  
Intravenous Ketamine

The present study tested the hypothesis that anesthetic agents can alter tissue O2 extraction capabilities in a dog model of progressive hemorrhage. After administration of pentobarbital sodium (25 mg/kg iv) and endotracheal intubation, the dogs were paralyzed with pancuronium bromide, ventilated with room air, and splenectomized. A total of 60 dogs were randomized in 10 groups of 6 dogs each. The first group served as control (C). A second group (P) received a continuous infusion of pentobarbital (4 mg.kg-2.h-2), which was started immediately after the bolus dose. Three groups received enflurane (E), halothane (HL), or isoflurane (I) at the end-tidal concentration of 0.7 minimum alveolar concentration (MAC). The sixth group received halothane at the end-tidal concentration of 1 MAC (HH). Two groups received intravenous alfentanil at relatively low dose (AL) or high dose (AH). The last two groups received intravenous ketamine at either relatively low dose (KL) or high dose (KH). In each group, O2 delivery (Do2) was progressively reduced by hemorrhage. At each step, systemic Do2 and O2 consumption (VO2) were measured separately and the critical point was determined from a plot of Vo2 vs. Do2. The critical O2 extraction ratio (OER) in the control group was 65.0 +/- 7.8%. OER was lower in all anesthetized groups (P, 44.3 +/- 11.8%; E, 47.0 +/- 7.7%; HL, 45.7 +/- 11.2%; I, 44.3 +/- 7.1%; HH, 33.7 +/- 6.0%; AL, 56.5 +/- 9.6%; AH, 43.5 +/- 5.9%; KH, 57.7 +/- 7.1%), except in the KL group (78.3 +/- 10.0%). The effects of halothane and alfentanil on critical OER were dose dependent (P less than 0.05), whereas critical OER was significantly lower in the KH than in the KL group. Moreover, the effects of anesthetic agents on critical Do2 appeared related to their effects on systemic vascular resistance. Anesthetic agents therefore alter O2 extraction by their peripheral vascular effects. However, ketamine, with its unique sympathetic stimulant properties, had a lesser effect on OER than the other anesthetic agents. It could therefore be the anesthetic agent of choice in clinical situations when O2 availability is reduced.

The Effect of Hypothermia on Isoflurane MAC in Children

2001 ◽  
Vol 94 (3) ◽  
pp. 429-432 ◽  
Author(s):  
Mingzheng Liu ◽  
Xiaoqin Hu ◽  
Jin Liu
Keyword(s):  
Minimum Alveolar Concentration ◽  
Heart Diseases ◽  
Skin Incision ◽  
Open Heart ◽  
Isoflurane Concentration ◽  
Inhaled Anesthetics ◽  
End Tidal

Background Hypothermia has been shown to decrease the requirement for inhaled anesthetics in animals, but information in humans is limited. Methods Thirty-three unpremedicated children with congenital left-to-right shunt heart diseases undergoing open heart surgeries were assigned to one of three groups, with nasopharyngeal temperatures at the time of skin incision of 37, 34, or 31 degrees C. Anesthesia was induced and maintained with isoflurane in oxygen. End-tidal isoflurane concentration and nasopharyngeal temperature were kept at stable levels for at least 15 min before the skin incision. Isoflurane minimum alveolar concentration was determined by using the Dixon up-and-down approach. Results Isoflurane minimum alveolar concentration values were 1.69 +/- 0.14%, 1.47 +/- 0.10%, and 1.22 +/- 0.15% (mean +/- SD) at 37, 34, and 31 degrees C, respectively. Conclusions Hypothermia decreases the isoflurane requirement in children by 5.1 degrees C.

Succinylcholine Dosage and Apnea-induced Hemoglobin Desaturation in Patients

2005 ◽  
Vol 102 (1) ◽  
pp. 35-40 ◽  
Author(s):  
Mohamed Naguib ◽  
Abdulhamid H. Samarkandi ◽  
Khaled Abdullah ◽  
Waleed Riad ◽  
Saleh W. Alharby
Keyword(s):  
Oxygen Saturation ◽  
Upper Airway ◽  
Study Drug ◽  
Face Mask ◽  
Saline Control ◽  
Control Group ◽  
Double Blind Study ◽  
Double Blind ◽  
The Face ◽  
End Tidal

Background The authors examined the notion that a reduction in succinylcholine dose from 1 mg/kg to approximately 0.6 mg/kg would allow a faster recovery of spontaneous ventilation and reduction in the incidence of hemoglobin desaturation during the period of apnea in simulated complete upper airway obstruction situations. Methods This prospective, randomized, double-blind study involved 60 patients. After preoxygenation to an end-tidal oxygen concentration &gt;90%, patients were anesthetized with 2 microg/kg fentanyl and 2 mg/kg propofol. After loss of consciousness, patients were randomly allocated to receive 0.56 or 1.0 mg/kg succinylcholine or saline (control group). Oxygen saturation was monitored continuously at the index finger. When the patient became apneic, the face mask was removed and the patient's airway was left unsupported. If the oxygen saturation decreased to 90%, the face mask was reapplied, and ventilation was assisted until the patient was awake. Time from injection of the study drug to the first visible spontaneous diaphragmatic movements was noted. Results Oxygen saturation decreased &lt;90% in 45%, 65%, and 85% of patients in the control, 0.56 mg/kg, and 1.0 mg/kg succinylcholine groups, respectively (P = 0.03). Corresponding times (mean +/- SD) to spontaneous of diaphragmatic movements were 2.7 +/- 1.2, 4.8 +/- 2.5, and 4.7 +/- 1.3 min, respectively. These times were longer (P &lt; 0.001) after either dose of succinylcholine compared with controls. Conclusions Reduction in succinylcholine dose from 1.0 mg/kg to 0.56 mg/kg decreased the incidence of hemoglobin saturation &lt;90% from 85% to 65% but did not shorten the time to spontaneous diaphragmatic movements. A significant fraction of patients would be at risk if there were failure to intubate and ventilate whether succinylcholine is administered or not and regardless of the dose of succinylcholine administered.

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.

scholarly journals Comparison of hemodynamic responses of intravenous dexmedetomidine and esmolol infusion during laparoscopic cholecystectomy

2018 ◽  
Vol 6 (4) ◽  
pp. 1429
Author(s):  
Azka Zuberi ◽  
Vaibhav Tiwary ◽  
Bhawana Rastogi ◽  
Kumkum Gupta ◽  
Abhishake Kumar ◽  
...  
Keyword(s):  
Laparoscopic Cholecystectomy ◽  
General Anesthesia ◽  
Normal Saline ◽  
Study Drug ◽  
Systemic Blood Pressure ◽  
Skin Incision ◽  
Control Group ◽  
Hemodynamic Stability ◽  
Set Up ◽  
Group B

Background: Laparoscopic cholecystectomy is one of the commonest surgery performed under general anesthesia in this set up but maintaining the hemodynamic stability is challenging in these patients. The present study was conducted to comparatively analyse the hemodynamic variations using intravenous dexmedetomidine and intravenous esmolol during laparoscopic cholecystectomy.Methods: Study was conducted on 90 adult patients aged 18-60 years, of ASA grade I or II of both gender, scheduled for laparoscopic cholecystectomy under general anesthesia. Patients were randomized into three groups of 30 patients each. Patients of Group A received esmolol infusion (loading: 1mg/kg and maintenance: 5-15µg/kg/min), patients of Group B received dexmedetomedine infusion (loading: 0.7µg/kg and maintenance: 0.4µg/kg/hr) and Group C (control group) received normal saline infusion. Patients were monitored for changes in heart rate, ECG, systemic blood pressure and EtCO2, at baseline, at 5 min and 10 min after giving study drug bolus, after induction, intubation, skin incision and CO2 insufflation. Thereafter, these changes were recorded at 15 min intervals till the end of surgery.Results: It was observed that perioperative use of dexmedetomidine and esmolol infusions maintained better hemodynamic stability as compared to the normal saline in control group. Though the patients in esmolol group showed less fluctuations in BP and HR (as compared to control group), but, stability was better in the patients of dexmedetomidine group at all-time intervals.Conclusions: Dexmedetomidine infusion was a better option for maintaining hemodynamic stability in comparison to emolol infusion during laparoscopic surgeries.

Association of Ethnicity with the Minimum Alveolar Concentration of Sevoflurane

2007 ◽  
Vol 107 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Tiberiu Ezri ◽  
Daniel Sessler ◽  
Marian Weisenberg ◽  
Gleb Muzikant ◽  
Michael Protianov ◽  
...  
Keyword(s):  
Selective Breeding ◽  
Minimum Alveolar Concentration ◽  
Skin Incision ◽  
Physical Status ◽  
The Caucasus ◽  
Lifestyle Choices ◽  
American Society ◽  
End Tidal ◽  
American Society Of Anesthesiologists ◽  
Animal Strains

Abstract Background: Selective breeding produces animal strains with varying anesthetic sensitivity. It thus seems unlikely that various human ethnicities have identical anesthetic requirements. Therefore, the authors tested the hypothesis that the minimum alveolar concentration of sevoflurane differs significantly as a function of ethnicity. Methods: The authors recruited 90 American Society of Anesthesiologists physical status I and II adult patients belonging to three Jewish ethnic groups: European, Oriental, and Caucasian (from the Caucasus Mountain region). All were scheduled to undergo surgery requiring a skin incision exceeding 3 cm. Without premedication, anesthesia was induced with 6–8% sevoflurane in 100% oxygen, and tracheal intubation was facilitated with succinylcholine. The skin incision was made after a predetermined end-tidal concentration of sevoflurane of 2.0% was maintained for at least 10 min in the first patient in each group. Blinded investigators observed the patient for movement during the subsequent minute. The concentration in the next patient was increased by 0.2% when patients moved, or decreased by the same amount when they did not. Results are presented as means [95% confidence intervals]. Results: Morphometric and demographic characteristics were similar among the groups; however, mean arterial pressure was slightly greater in European Jews. Minimum alveolar concentration for sevoflurane was greatest in Caucasian Jews (2.32% [2.27–2.41%]), less in Oriental Jews (2.14% [2.06–2.22%]), and still less in European Jews (1.9% [1.82–1.99%]) (P &lt; 0.001). Conclusions: The results suggest that minimum alveolar concentration varies as a function of ethnicity. However, the extent to which confounding characteristics contribute, including lifestyle choices and environmental factors, remains unknown.

scholarly journals Effect of epidural administration of lidocaine, fentanyl and their combination on the minimum alveolar concentration of halothane in dogs

2012 ◽  
Vol 49 (No. 11) ◽  
pp. 421-426
Author(s):  
P. Rauser ◽  
L. Lexmaulova ◽  
M. Vlasin ◽  
T. Fichtel ◽  
J. Lorenzova
Keyword(s):  
Minimum Alveolar Concentration ◽  
Control Group ◽  
Epidural Administration ◽  
General Anesthetics ◽  
Mutual Relationship ◽  
Significant Difference ◽  
Basic Parameters ◽  
Healthy Dogs ◽  
End Tidal ◽  
Vital Parameters

The efficacy of lidocaine, fentanyl, combination of both (2 mg/kg of lidocaine, along with fentanyl in the dose of 0.005 mg/kg) and saline (as a control) administered epidurally to 40 healthy dogs was under investigation, regarding their influence on minimum alveolar concentration (MAC) of halothane. Basic vital parameters, such as heart rate, respiratory rate, saturation of hemoglobin with oxygen and end-tidal partial pressure of CO<sub>2</sub> were recorded. Minimum alveolar concentration of halothane after administration of lidocaine (0.75 ± 0.24%), or the lidocaine/fentanyl combination (0.43 ± 0.08%) was found to be significantly lower (p &lt; 0.05) compare to control group (1.15 ± 0.20%). However, we have not found significant difference in the group given fentanyl alone (0.95 ± 0.35%) compare to control group. Mutual relationship between epidurally given lidocaine and fentanyl (same route of administration) can be called as simply additive. There were no significant deviations in basic parameters within groups. We conclude that epidural administration of combination of these drugs we are able to reduce the dose of general anesthetics, which is important in management of critically ill patients.

The Minimum Alveolar Concentration of Xenon in the Elderly Is Sex-dependent

2002 ◽  
Vol 97 (5) ◽  
pp. 1129-1132 ◽  
Author(s):  
Takahisa Goto ◽  
Yoshinori Nakata ◽  
Shigeho Morita
Keyword(s):  
Regression Analysis ◽  
Minimum Alveolar Concentration ◽  
The Elderly ◽  
Skin Incision ◽  
Men And Women ◽  
Mk 801 ◽  
Bodily Movement ◽  
Aspartate Receptor ◽  
Significant Difference ◽  
End Tidal

Background The minimum alveolar concentration (MAC) of xenon in the elderly has not been determined. Moreover, because xenon inhibits the activity of the N-methyl-D-aspartate receptors, and because N-methyl-D-aspartate receptor antagonists such as ketamine and MK-801 exert sex-dependent actions, we hypothesized that the MAC of xenon would also be sex-dependent. Methods Forty-eight patients of both sexes (24 patients of each sex), who were aged 65 yr or older and were undergoing elective laparotomy, were anesthetized with inhalational induction of xenon. Those who demonstrated marked agitation received supplemental propofol intravenously. After tracheal intubation, the end-tidal concentration of xenon was maintained at 45 (women only), 50, 55, 60, 65, 70, or 75% (men only) for at least 15 min before skin incision. These concentrations were randomly allocated to four patients of each sex. Each patient was monitored for the presence or absence of any purposeful bodily movement for 1 min following skin incision. The MAC of xenon was calculated separately for men and women using logistic regression analysis. Results The MAC of xenon was 69.3% (95% CI, 63.0-75.6%) for men and 51.1% (44.6-57.6%) for women. The two 95% confidence intervals did not overlap, indicating a statistically significant difference (P &lt; 0.05). Conclusions The MAC of xenon in the elderly is higher in men than in women.

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