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.

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.

Minimum Alveolar Concentration (MAC) of Xenon with Sevoflurane in Humans

2001 ◽  
Vol 94 (4) ◽  
pp. 611-614 ◽  
Author(s):  
Yoshinori Nakata ◽  
Takahisa Goto ◽  
Yoshiki Ishiguro ◽  
Katsuo Terui ◽  
Hiromasa Kawakami ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Minimum Alveolar Concentration ◽  
Interaction Coefficient ◽  
Bodily Movement ◽  
Xenon Concentration ◽  
Multiple Variable ◽  
End Tidal ◽  
Somatic Response ◽  
Technological Limitations ◽  
Group Target

Background Although more than 30 yr ago the minimum alveolar concentration (MAC) of xenon was determined to be 71%, that previous study had technological limitations, and no other studies have confirmed the MAC value of xenon since. The current study was designed to confirm the MAC value of xenon in adult surgical patients using more modern techniques. Methods Sixty patients were anesthetized with sevoflurane with or without xenon. They were randomly allocated to one of four groups; patients in group 1 received no xenon, whereas those in groups 2, 3, and 4 received end-tidal concentrations of 20, 40, and 60%, respectively (n = 15 each group). Target end-tidal sevoflurane concentrations were chosen using the "up-and-down" method in each group. After steady state sevoflurane and xenon concentrations were maintained for at least 15 min, each patient was monitored for a somatic response at surgical incision. Somatic response was defined as any purposeful bodily movement. The MAC of sevoflurane and its reduction by xenon was evaluated using the multiple independent variable logistic regression model. Results The interaction coefficient of the multiple variable logistic regression was not significantly different from zero (P = 0.143). The MAC of xenon calculated as xenon concentration that would reduce MAC of sevoflurane to 0% was 63.1%. Conclusions The authors could not determine whether interaction in blocking somatic responses in 50% of patients is additive. The MAC of xenon is in the range of the values that were predicted in a previous study.

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.

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

2000 ◽  
Vol 44 (3) ◽  
pp. 156
Author(s):  
HILTON D. SWAN ◽  
MARK W. CRAWFORD ◽  
HWEE LING PUA ◽  
DEREK STEPHENS ◽  
JERROLD LERMAN
Keyword(s):  
Nitrous Oxide ◽  
Tracheal Intubation ◽  
Minimum Alveolar Concentration ◽  
Additive Contribution

The Effect of Isoflurane, Halothane, Sevoflurane, and Thiopental/Nitrous Oxide on Respiratory System Resistance after Tracheal Intubation 

1997 ◽  
Vol 86 (6) ◽  
pp. 1294-1299 ◽  
Author(s):  
G. Alec Rooke ◽  
Jong-Ho Choi ◽  
Michael J. Bishop
Keyword(s):  
Nitrous Oxide ◽  
Tracheal Intubation ◽  
Respiratory System ◽  
Minimum Alveolar Concentration ◽  
Volatile Anesthetics ◽  
Human Data ◽  
Lung Resistance ◽  
Respiratory System Resistance ◽  
End Tidal

Background After tracheal intubation, lung resistance and therefore respiratory system resistance (R[rs]) routinely increase, sometimes to the point of clinical bronchospasm. Volatile anesthetics generally have been considered to be effective bronchodilators, although there are few human data comparing the efficacy of available agents. This study compared the bronchodilating efficacy of four anesthetic maintenance regimens: 1.1 minimum alveolar concentration (MAC) end-tidal sevoflurane, isoflurane or halothane, and thiopental/nitrous oxide. Methods Sixty-six patients underwent tracheal intubation after administration of 2 microg/kg fentanyl, 5 mg/kg thiopental, and 1 mg/kg succinylcholine. Vecuronium or pancuronium (0.1 mg/kg) was then given to ensure paralysis during the rest of the study. Postintubation R(rs) was measured using the isovolume technique. Maintenance anesthesia was then randomized to thiopental 0.25 mg x kg(-1) x min(-1) plus 50% nitrous oxide, or 1.1 MAC end-tidal isoflurane, halothane, or sevoflurane. The R(rs) was measured after 5 and 10 min of maintenance anesthesia. Data were expressed as means +/- SD. Results Maintenance with thiopental/nitrous oxide failed to decrease R(rs), whereas all three volatile anesthetics significantly decreased R(rs) at 5 min with little further improvement at 10 min. Sevoflurane decreased R(rs) more than either halothane or isoflurane (P < 0.05; 58 +/- 14% of the postintubation R(rs) vs. 69 +/- 20% and 75 +/- 13%, respectively). Conclusions After tracheal intubation in persons without asthma, sevoflurane decreased R(rs) as much or more than isoflurane or halothane did during a 10-min exposure at 1.1 MAC.

Oral Clonidine Premedication Reduces Minimum Alveolar Concentration of Sevoflurane for Tracheal Intubation in Children 

1997 ◽  
Vol 87 (6) ◽  
pp. 1324-1327 ◽  
Author(s):  
Kahoru Nishina ◽  
Katsuya Mikawa ◽  
Makoto Shiga ◽  
Nobuhiro Maekawa ◽  
Hidehumi Obara
Keyword(s):  
Nitrous Oxide ◽  
Tracheal Intubation ◽  
Minimum Alveolar Concentration ◽  
The Other ◽  
Placebo Control ◽  
Inhaled Anesthetics ◽  
Inhalational Induction ◽  
Oral Clonidine ◽  
Low Solubility

Background Sevoflurane is a useful anesthetic for inhalational induction in children because of its low solubility in blood and relatively nonpungent odor. Clonidine has sedative and anxiolytic properties and reduces the requirement for inhalation agents. Nitrous oxide (N2O) also decreases the requirement of inhaled anesthetics, but the effect is variable. The minimum alveolar concentration for tracheal intubation (MAC(TI)) of sevoflurane was assessed with and without N2O and clonidine premedication. Methods Seventy-two patients, aged 3-11 yr, were assigned to one of six groups (n = 12 each). They received one of three preanesthetic medications (two groups for each premedication): placebo (control), 2 microg/kg oral clonidine or 4 microg/kg oral clonidine. In one group of each premedication, anesthesia was induced with sevoflurane in oxygen; in the other group, anesthesia was induced with sevoflurane in the presence of 60% N2O. Each concentration of sevoflurane at which tracheal intubation was attempted was predetermined according to Dixon's up-and-down method and held constant for at least 20 min before the trial Results The MAC(TI) of sevoflurane in the absence of N2O (mean +/- SEM) was 3.2 +/- 0.2%, 2.5 +/- 0.1%, and 1.9 +/- 0.2% in the control, 2-microg/kg clonidine, and 4-microg/kg clonidine groups, respectively. Nitrous oxide (60%) decreased the MAC(TI) of sevoflurane by 26%, 24%, and 27% in the control, 2-microg/kg clonidine, and 4-microg/kg clonidine groups. Conclusions Oral clonidine premedication decreased the MAC(TI) of sevoflurane. Nitrous oxide also decreased the MAC(TI). The combination of clonidine and N2O lessened the MAC(TI) of sevoflurane more than did either drug alone.

scholarly journals Effects of nitrous oxide on minimum alveolar concentration of desflurane in dogs

2007 ◽  
Vol 59 (1) ◽  
pp. 97-104 ◽  
Author(s):  
C.T. Nishimori ◽  
N. Nunes ◽  
D.P. Paula ◽  
M.L. Rezende ◽  
A.P. Souza ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Nitrous Oxide ◽  
Body Temperature ◽  
Minimum Alveolar Concentration ◽  
Electric Stimulus ◽  
Oxyhemoglobin Saturation ◽  
End Tidal Carbon Dioxide ◽  
Desflurane Concentration ◽  
Blood Pressures ◽  
End Tidal

Effects of nitrous oxide (N2O) on minimum alveolar concentration (MAC) of desflurane were studied. For that purpose, 30 dogs were randomly allocated into two groups: desflurane group (GD) and N2O and desflurane group (GDN). GD animals received propofol to intubation, and 11.5V% of desflurane diluted in 100% O2. After 30 minutes, they received electric stimulus and if the animal did not react to stimulus, desflurane concentration was reduced by 1.5V%. This protocol was repeated at each 15 minutes, and stimulus was interrupted when voluntary reaction was observed. GDN dogs were submitted to diluent flow 30% O2 and 70% N2O. Desflurane's MAC; heart (HR) and respiratory (RR) rates; systolic, diastolic and mean arterial pressures (SAP, DAP, and MAP, respectively); end tidal carbon dioxide (ETCO2); oxyhemoglobin saturation (SpO2) and body temperature (T) were evaluated. In both groups increase in HR and ETCO2, and decrease in RR and T were associated with administration of the highest dose of desflurane. Blood pressures decreased 30 minutes after desflurane administration in GDN, and after this measurement the values increased. Reduction in desflurane's MAC was observed as well. It is concluded that N2O associated with desflurane reduced desflurane's MAC by 16% with increase in HR and respiratory depression.

Subjective, Psychomotor, Cognitive, and Analgesic Effects of Subanesthetic Concentrations of Sevoflurane and Nitrous Oxide 

1997 ◽  
Vol 87 (5) ◽  
pp. 1082-1088 ◽  
Author(s):  
Jeffrey L. Galinkin ◽  
Debra Janiszewski ◽  
Christopher J. Young ◽  
Jerome M. Klafta ◽  
P. Allan Klock ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Chemical Nature ◽  
Minimum Alveolar Concentration ◽  
Cold Water ◽  
Cognitive Effects ◽  
General Anesthetic ◽  
Analgesic Effects ◽  
Pain Ratings ◽  
Water Test ◽  
End Tidal

Background Sevoflurane is a volatile general anesthetic that differs in chemical nature from the gaseous anesthetic nitrous oxide. In a controlled laboratory setting, the authors characterized the subjective, psychomotor, and analgesic effects of sevoflurane and nitrous oxide at two equal minimum alveolar subanesthetic concentrations. Methods A crossover design was used to test the effects of two end-tidal concentrations of sevoflurane (0.3% and 0.60%), two end-tidal concentrations of nitrous oxide (15% and 30%) that were equal in minimum alveolar concentration to that of sevoflurane, and placebo (100% oxygen) in 12 healthy volunteers. The volunteers inhaled one of these concentrations of sevoflurane, nitrous oxide, or placebo for 35 min. Dependent measures included subjective, psychomotor, and physiologic effects, and pain ratings measured during a cold-water test. Results Sevoflurane produced a greater degree of amnesia, psychomotor impairment, and drowsiness than did equal minimum alveolar concentrations of nitrous oxide. Recovery from sevoflurane and nitrous oxide effects was rapid. Nitrous oxide but not sevoflurane had analgesic effects. Conclusions Sevoflurane and nitrous oxide produced different profiles of subjective, behavioral, and cognitive effects, with sevoflurane, in general, producing an overall greater magnitude of effect. The differences in effects between sevoflurane and nitrous oxide are consistent with the differences in their chemical nature and putative mechanisms of action.

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.

Effects of Xenon on Hemodynamic Responses to Skin Incision in Humans 

1999 ◽  
Vol 90 (2) ◽  
pp. 406-410 ◽  
Author(s):  
Yoshinori Nakata ◽  
Takahisa Goto ◽  
Shigeho Morita
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Nitrous Oxide ◽  
Systolic Blood Pressure ◽  
Minimum Alveolar Concentration ◽  
Skin Incision ◽  
Hemodynamic Responses ◽  
Probable Explanation ◽  
Hemodynamic Variables ◽  
To Receive

Background The authors evaluated the hemodynamic suppressive effects of xenon in combination with sevoflurane at skin incision in patients undergoing surgery. Methods Forty patients were assigned randomly to receive one of the following four anesthetics: 1.3 minimum alveolar concentration (MAC) sevoflurane, 0.7 MAC xenon with 0.6 MAC sevoflurane, 1 MAC xenon with 0.3 MAC sevoflurane, or 0.7 MAC nitrous oxide with 0.6 MAC sevoflurane (n = 10 each group). Systolic blood pressure and heart rate were measured before anesthesia, before incision, and approximately 1 min after incision. Results The changes in hemodynamic variables in response to incision were less with sevoflurane in combination with xenon and nitrous oxide than with sevoflurane alone. Changes in heart rate (in beats/min) were 19+/-11 (+/- SD) for sevoflurane alone, 11+/-6 for 0.7 MAC xenon-sevoflurane, 4+/-4 for 1 MAC xenon-sevoflurane, and 8+/-7 for nitrous oxide-sevoflurane. Changes in systolic blood pressure were 35+/-18 mmHg for sevoflurane alone, 18+/-8 mmHg for 0.7 MAC xenon-sevoflurane, 16+/-7 mmHg for 1 MAC xenon-sevoflurane, and 14+/-10 mmHg for nitrous oxide-sevoflurane. Conclusions Xenon and nitrous oxide in combination with sevoflurane can reduce hemodynamic responses to skin incision compared with sevoflurane alone. One probable explanation may be that xenon has analgesic properties similar to those of nitrous oxide, although the exact mechanism is yet to be determined.

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