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PubMed1995

Cytochrome c oxidase catalysis of the reduction of nitric oxide to nitrous oxide.

Reduction of nitric oxide (NO) to nitrous oxide (N2O) is catalyzed by bovine heart cytochrome c oxidase (CcO) in anaerobic solutions at pH 7.2 and 20 degrees C. Cyanide inhibits and forms Fea3(3+)CN. The mononitrosyl (Fea3(2+)NO), but not the dinitrosyl (Fea3(2+)NO; CuB+NO), is a likely intermediate in N2O formation. One-electron reduction of NO at Fea3(2+) could yield N2O via HNO. However, a two-electron reduction of the NO ligand to give an intermediate that reacts with a second NO to give N2O and H2O appears more likely. Conversion of NO to N2O is favored by low levels of both NO and O2, higher NO levels can inhibit both cytochrome c oxidase and NO reductase activities. Raising the O2 level will favor catalysis of NO oxidation to NO2 by CcO. The reactions of NO and the specific CcO activity that occur in tissue will be critically dependent on NO, O2, and CcO levels.

Animals↗
PubMed2002

Assessing nitrate metabolism in the intestinal tract by measuring breath nitric oxide and nitrous oxide, and its clinical significance.

BACKGROUND: The toxicity of dietary nitrate (NO3-) is controversial. One reason is nitrate metabolism in the intestine is so complicated that it is far from fully understood. There is no study measuring breath nitric oxide (NO) and nitrous oxide (N2O) after ingesting vegetables and high-nitrate food at the same time. METHODS: Breath samples from 10 healthy young and 10 healthy old subjects were collected at 15-min intervals for 5 h after ingestion of 100 g of lettuce and during fasting (control). Breath NO and N2O were analyzed by a chemiluminescence and an IR-PAS analyzer respectively. RESULTS: N2O maximum concentration and excretions increased significantly after ingesting lettuce in each group [303 (30) vs. 750 (81) ppb, 771 (72) vs. 1668 (146) microg in young; 442 (52) vs. 1092 (109) ppb, 1088 (125) vs. 2100 (183) microg in old subjects; mean (SE), P<0.01], while NO did not. In addition, breath NO was strongly influenced by ambient NO, which varied greatly. N2O maximum level in old subjects after ingesting lettuce was higher than that of young subjects (750 vs. 1092 ppb, P<0.05), and significantly higher N2O concentration levels were seen at 30, 45, 60, and 105 min in old subjects. CONCLUSIONS: A large amount of N2O produced in the intestine and normal nitrate intake do not influence the breath NO concentration, probably due to its relatively small production. Higher maximum N2O concentration after ingesting lettuce in old subject is probably because more bacteria, which rapidly reduce dietary nitrate in the upper intestinal tract, inhabit the gut in old age. Our results suggested that breath N2O is a useful noninvasive maker to estimate dietary nitrate reduction in the intestinal tract.

Adult↗
PubMed1986

Relative rates of nitric oxide and nitrous oxide production by nitrifiers, denitrifiers, and nitrate respirers.

Biogenic emissions of nitric and nitrous oxides have important impacts on the photochemistry and chemistry of the atmosphere. Although biogenic production appears to be the overwhelming source of N(2)O, the magnitude of the biogenic emission of NO is very uncertain. In soils, possible sources of NO and N(2)O include nitrification by autotrophic and heterotrophic nitrifiers, denitrification by nitrifiers and denitrifiers, nitrate respiration by fermenters, and chemodenitrification. The availability of oxygen determines to a large extent the relative activities of these various groups of organisms. To better understand this influence, we investigated the effect of the partial pressure of oxygen (pO(2)) on the production of NO and N(2)O by a wide variety of common soil nitrifying, denitrifying, and nitrate-respiring bacteria under laboratory conditions. The production of NO per cell was highest by autotrophic nitrifiers and was independent of pO(2) in the range tested (0.5 to 10%), whereas N(2)O production was inversely proportional to pO(2). Nitrous oxide production was highest in the denitrifier Pseudomonas fluorescens, but only under anaerobic conditions. The molar ratio of NO/N(2)O produced was usually greater than unity for nitrifiers and much less than unity for denitrifiers. Chemodenitrification was the major source of both the NO and N(2)O produced by the nitrate respirer Serratia marcescens. Chemodenitrification was also a possible source of NO and N(2)O in nitrifier cultures but only when high concentrations of nitrite had accumulated or were added to the medium. Although most of the denitrifiers produced NO and N(2)O only under anaerobic conditions, chemostat cultures of Alcaligenes faecalis continued to emit these gases even when the cultures were sparged with air. Based upon these results, we predict that aerobic soils are primary sources of NO and that N(2)O is produced only when there is sufficient soil moisture to provide the anaerobic microsites necessary for denitrification by either denitrifiers or nitrifiers.

Journal Article↗
PubMed1994

Effects of isoflurane-nitrous oxide and halothane-nitrous oxide anaesthesia on myocardial contractility assessed by transoesophageal echocardiography.

In order to evaluate the direct effect of isoflurane-nitrous oxide and halothane-nitrous oxide anaesthesia on cardiac contractility in 20 adults, we have used a method based on left ventricular end-systolic wall stress (LVESWS) vs velocity of circumferential fibre shortening with corrected heart rate (Vcfc), obtained by transoesophageal echocardiography. We found that LVESWS (index of afterload) decreased significantly with isoflurane-nitrous oxide (n = 10) in concentrations of 1.5-1.95 MAC, but there were no significant changes in LVESWS with halothane-nitrous oxide (n = 10). Vcfc decreased significantly with halothane-nitrous oxide in concentrations of 1.5-1.95 MAC, but this index did not change significantly with isoflurane-nitrous oxide. However, there was no significant difference between the two groups in LVESWS or Vcfc. In the analysis of the LVESWS-Vcfc relationship, myocardial contractility associated with isoflurane-nitrous oxide anaesthesia did not differ significantly from that associated with halothane-nitrous oxide anaesthesia at equiMAC concentrations. The results suggest that halothane-nitrous oxide anaesthesia, at 1.5-1.95 MAC, maintained myocardial contractility in similar anaesthetic concentrations to isoflurane-nitrous oxide.

Adult↗
PubMedDate not supplied

Effects of intravenous mepivacaine on renal sympathetic nerve activity in the cat during nitrous oxide and nitrous oxide-halothane anesthesia.

BACKGROUND AND OBJECTIVES: Because hemodynamic responses to systemic mepivacaine may be influenced by sympathetic change and concurrent general anesthesia, the authors directly measured renal sympathetic nerve activity (RSNA) during intravenous administration of mepivacaine in subseizure through seizure doses under N2O-O2 and N2O-O2-halothane anesthesia. METHODS: Thirty-four cats were randomly assigned to five groups. Groups I-A, I-B, and I-C received incremental subseizure doses of intravenous mepivacaine (2 mg/kg, 5 mg/kg, and 10 mg/kg). Groups II-A and II-B received intravenous infusion of mepivacaine (4 mg/kg/min). Anesthesia was maintained with N2O(70%)-O2 in groups I-A, I-C, and II-A, and with N2O(70%)-O2-halothane (1%) in groups I-B and II-B. Cats in group I-C had undergone total baroreceptor denervation. Heart rate (HR), mean arterial pressure (MAP), and RSNA were measured. RESULTS: In group I-A, MAP did not significantly change with intravenous mepivacaine, though RSNA and HR significantly decreased (P < .05) respectively with 5 mg/kg i.v. and 10 mg/kg i.v. mepivacaine. In group I-C, HR, MAP, and RSNA did not change significantly. In group I-B, HR and MAP decreased with bolus intravenous doses of mepivacaine in a dose-dependent fashion, but RSNA did not change significantly. All cats in group II-A developed seizure by mepivacaine infusion at mean total dose of 28.9 +/- 4.2 mg/kg without significant changes in HR, MAP, or RSNA. In group II-B, mepivacaine infusion resulted in circulatory collapse at mean total dose of 34.3 +/- 4.6 mg/kg without seizure or significant RSNA change. CONCLUSIONS: The authors conclude that intravenous mepivacaine induces occasional depression in HR and RSNA during N2O-O2 anesthesia, but in addition induces dose-related circulatory depression during N2O-O2-halothane anesthesia via nonsympathetic mechanism(s).

Anesthesia, Inhalation↗
PubMed1981

Cross-mating of mice selectively bred for resistance or susceptibility to nitrous oxide anesthesia: potencies of nitrous oxide in offspring.

To investigate the genetic bases of differences in nitrous oxide requirement in mice selectively bred for resistance (HI mice) or susceptibility (LO mice) to nitrous oxide anesthesia, the potency of nitrous oxide in offspring having one HI and one LO parent was measured. Nitrous oxide ED50S (+/- SD) in offspring having HI male and LO female parents or LO male and HI female parents were 1.53 +/- 0.10 and 1.63 +/- 0.14 atm, respectively. In contrast, the nitrous oxide ED50 for offspring having two LO parents was 1.26 +/- 0.09 atm, and for offspring having two HI parents, 1.96 +/- 0.10 atm. Thus, the nitrous oxide ED50S for offspring produced by cross-mating HI and LO animals approximated the average values for their parents. We conclude that no single one gene determines dominance or recessiveness for nitrous oxide requirement in mice, and that the genetic control of resistance or susceptibility to nitrous oxide anesthesia probably involves many genes.

Anesthetics↗
PubMed1985

Neuromuscular effects of atracurium during halothane-nitrous oxide and enflurane-nitrous oxide anesthesia in humans.

To compare the effect of halothane and enflurane on an atracurium-induced neuromuscular blockade, the authors studied 40 patients during elective surgery. During 1.25 MAC enflurane-nitrous oxide (n = 20) or halothane-nitrous oxide (n = 20) (MAC value includes contribution from 60% nitrous oxide), the doses depressing twitch tension 50% (ED50S) for atracurium were 70 and 77 micrograms/kg, respectively. The difference was not significant. Time from injection to peak effect did not differ between groups. However, the duration of action of atracurium (expressed as duration 50 or the duration of a 50% blockade) was longer during enflurane-nitrous oxide anesthesia (34.2 min) than during halothane-nitrous oxide anesthesia (25.5 min) (P less than 0.05). The authors conclude that the potency of atracurium does not differ during halothane-nitrous oxide and enflurane-nitrous oxide anesthesia. Combining the results of this study with a previous study (atracurium ED50 = 68 micrograms/kg and 83 micrograms/kg during isoflurane-nitrous oxide and fentanyl-nitrous oxide anesthesia respectively), the potency of atracurium does not differ by more than 20% among the four anesthetic techniques studied. The background anesthetic appears to have less effect on an atracurium-induced neuromuscular blockade than on one produced by other longer-acting nondepolarizing muscle relaxants (e.g., pancuronium and d-tubocurarine).

Adult↗
PubMed2001

Post-operative nausea and vomiting in out-patient gynecologic laparoscopy: a comparison of thiopental-nitrous oxide, propofol-nitrous oxide and total intravenous anesthesia using propofol.

An intravenous anesthetic drug, propofol was considered to pose antiemetic action. A randomized controlled trial was conducted to evaluate whether propofol could effectively reduce post-operative nausea and vomiting (PONV) compared to thiopental-nitrous oxide (N2O). One-hundred and eight patients undergoing outpatient gynecologic laparoscopy were assigned to receive 3 techniques of anesthesia; thiopental-N2O (T/N), propofol-N2O (P/N) and total intravenous anesthesia (TIVA) using propofol (P/P). The results showed that in the early period (0-5 hours), post-operative nausea in T/N, P/N and P/P groups was 72 per cent, 44 per cent and 31 per cent, respectively (P = 0.002), and post-operative vomiting was 58 per cent, 36 per cent and 11 per cent respectively (P = 0.00014). Patients in the P/N and P/P groups experienced nausea less frequently than the T/N group [relative risk (RR) = 0.62, (95% CI 0.41-0.93) and RR = 0.42 (0.25-0.72) respectively]. Patients in the P/N and P/P groups experienced vomiting less frequently than the T/N group [RR = 0.62 (0.37-1.04) and RR = 0.19 (0.07-0.5) respectively]. Two patients in the T/N group were admitted because of severe nausea and vomiting. In conclusion, TIVA using propofol and propofol-N2O anesthesia can significantly reduce the incidence of PONV in the early period. Concerning the economic crisis of the country as well as the quality of care, propofol-N2O would be the most appropriate anesthetic of choice.

Adult↗
PubMed1989

Nitric oxide and nitrous oxide production and cycling during dissimilatory nitrite reduction by Pseudomonas perfectomarina.

The denitrifier Pseudomonas perfectomarina reduced nitrite under conditions of kinetic competition between cells and gas sparging for extracellular dissolved nitric and nitrous oxides, NOaq and N2Oaq, in a chemically defined marine medium. Time courses of nitrite reduction and NOg and N2Og alpha removal were integrated to give NOg and N2Og yields. At high sparging rates, the NOg yield was greater than 50% of nitrite-N reduced, and the yield of NOg + N2Og was approximately 75%. Hence interrupted denitrification yields NOaq and N2Oaq as major products. The yields varied with sparging rates in agreement with a quantitative model of denitrification (Betlach, M. P., and Tiedje, J.M. (1981) Appl. Environ. Microbiol. 42, 1074-1084) that applies simplified Michaelis-Menten kinetics to NO2-----NOaq----N2Oaq----N2. The fit gave an estimate of the maximum scavengeable NOaq yield of 73 +/- 8% of nitrite-N. Thus a minor path independent of NOaq is also required. The fit of the model to data at lower sparging rates, where normal denitrification products predominate, implies that the extracellular NOaq pool yield is independent of gas sparging rate. Thus in P. perfectomarina NOaq and N2Oaq are intermediates, or facilely equilibrate with true intermediates, during complete denitrification. The recovery of most nitrite-N as NO and/or N2O under perturbed conditions is not an artifact of irreversible product removal, but an attribute of denitrification in this species, and most probably it is characteristic of denitrification in other species as well.

Kinetics↗
PubMed2006

Comparison of the anesthesia profiles between sevoflurane-nitrous oxide and propofol-nitrous oxide conveyed by laryngeal mask airway in patients undergoing ambulatory gynecological surgery.

BACKGROUND: The major purpose of this study is to evaluate and compare the clinical characteristics of sevoflurane-nitrous oxide and propofol-nitrous oxide anesthesias conveyed by laryngeal mask airway (LMA) in patients for gynecological procedures. METHODS: Eighty female patients were randomly assigned to one of the two groups: Group I, inhalational induction at vital capacity with 8% sevoflurane and 67% nitrous oxide in oxygen; Group II, induction with intravenous propofol at 2 mg/kg followed by intravenous infusion at 6 mg/kg/hr. The LMA was inserted after loss of response to jaw thrusting. After successful insertion, in group I anesthesia was maintained with sevoflurane and 67% nitrous oxide in O2 and in group II anesthesia was maintained with propofol at 6 mg/kg/hr and nitrous oxide 67% in oxygen. Anesthetic profiles, including insertion event, postoperative nausea and vomiting, and hemodynamic alterations were compared. RESULTS: Demographic data were comparable in the two groups. After induction, in group II unconsciousness was produced 59 sec shorter than that in group I for placement of LMA. Group I had a higher statistically significant rate of cough upon induction, and by the same token postoperative nausea and vomiting. There were no significant differences in hemodynamic alterations, as well as time to open eyes on command, and time to regain orientation. CONCLUSIONS: Intravenous propofol in combination with 67% nitrous oxide in oxygen technique provided better clinical profiles, compared with sevoflurane-nitrous oxide technique through the use of LMA in gynecological patients undergoing ambulatory short procedures.

Adult↗
PubMed2004

Electrocatalytic reductions of nitrite, nitric oxide, and nitrous oxide by thermophilic cytochrome P450 CYP119 in film-modified electrodes and an analytical comparison of its catalytic activities with myoglobin.

Previous investigations of nitrite and nitric oxide reduction by myoglobin in surfactant film modified electrodes characterized several distinct steps in the denitrification pathway, including isolation of a nitroxyl adduct similar to that proposed in the P450nor catalytic cycle. To investigate the effect of the axial ligand on these biomimetic reductions, we report here a comparison of the electrocatalytic activity of myoglobin (Mb) with a thermophilic cytochrome P450 CYP119. Electrocatalytic nitrite reduction by CYP119 is very similar to that by Mb: two catalytic waves at analogous potentials are observed, the first corresponding to the reduction of nitric oxide, the second to the production of ammonia. CYP119 is a much more selective catalyst, giving almost exclusively ammonia during the initial half-hour of reductive electrolysis of nitrite. More careful investigations of specific steps in the catalytic cycle show comparable rates of nitrite dehydration and almost identical potentials and lifetimes for ferrous nitroxyl intermediate (Fe(II)-NO(-)) in CYP119 and Mb. The catalytic efficiency of nitric oxide reduction is reduced for CYP119 as compared to Mb, attributable to both a lower affinity of the protein for NO and a decreased rate of N-N coupling. Isotopic labeling studies show ammonia incorporation into nitrous oxide produced during nitrite reduction, as has been termed co-denitrification for certain bacterial and fungal nitrite reductases. Mb has a much higher co-denitrification activity than CYP119. Conversely, CYP119 is shown to be slightly more efficient at the two-electron reduction of N(2)O to N(2). These results suggest that thiolate ligation does not significantly alter the catalytic reactivity, but the dramatic difference in product distribution may suggest an important role for protein stability in the selectivity of biocatalysts.

Ammonia↗
PubMed2005

Stress hormone changes in general anesthesia of long duration: isoflurane-nitrous oxide vs sevoflurane-nitrous oxide anesthesia.

STUDY OBJECTIVE: There are few comparative studies of stress hormone changes during general anesthesia with long duration between isoflurane-nitrous oxide and sevoflurane-nitrous oxide anesthesia. We investigated perioperative changes of stress hormone in these two anesthetic methods with duration of more than 10 hours. DESIGN: Prospective study. SETTING: Operating room and high care unit of a university hospital. PATIENTS: Twenty patients with ASA physical status I or II for surgery for laryngeal or pharyngeal cancer with expected duration of more than 10 hours. INTERVENTIONS: Anesthesia was induced with midazolam, thiopental, and vecuronium and was maintained with sevoflurane (sevoflurane group) or isoflurane (isoflurane group) with nitrous oxide 4 L/min in oxygen 2 L/min. MEASUREMENTS AND MAIN RESULTS: Plasma concentrations of epinephrine, norepinephrine, cortisol, adrenocorticotropic hormone, and anti-diuretic hormone (ADH); serum concentrations of glucagon and insulin; and blood glucose concentration were measured before inhalation of anesthetics, after 5 and 10 hours, and at 1, 6, and 12 hours after the end of inhalation. Epinephrine and norepinephrine concentrations increased continuously during and after surgery in the isoflurane group whereas it increased only after surgery in the sevoflurane group. Both concentrations were higher in the isoflurane group during anesthesia. Cortisol increased continuously whereas adrenocorticotropic hormone increased only during surgery. Anti-diuretic hormone increased with its peak during surgery and the isoflurane group had significantly higher values than the sevoflurane group. Glucose increased both during and after surgery, insulin increased only after surgery, and glucagon decreased during surgery in both groups. CONCLUSIONS: In inhalation anesthesia with the duration of more than 10 hours, isoflurane-nitrous oxide and sevoflurane-nitrous oxide had the same effects on stress hormone changes except for epinephrine, norepinephrine, and ADH. Epinephrine, norepinephrine, and ADH concentrations were higher in isoflurane-nitrous oxide anesthesia.

Adrenocorticotropic Hormone↗
PubMed1999

15N Analysis of nitric oxide and nitrous oxide by cryotrap enrichment using a gas chromatograph quadrupole mass spectrometer and its application to (15)N-tracer investigations of NO/N(2)O formation in soil.

Nitric oxide (NO) and nitrous oxide (N(2)O) are two important trace gases in the atmosphere. Determining the concentration and (15)N abundance of NO and N(2)O in air is difficult owing to their very low concentration in the atmosphere (NO < 1 ppb(v); N(2)O approximately 0.32 ppm(v)). Although (15)N analysis of N(2)O in ambient concentrations can be carried out using a gas chromatograph quadrupole mass spectrometer system (GC-QMS) and a dosage of 2 mL of air by means of a sample loop, this system is not sensitive enough to measure the ambient concentration of NO and its (15)N abundance. Therefore the concentration of NO must be enriched by cryotrapping (cooling with liquid nitrogen). The (15)N analytical method developed enables the sensitive and sufficiently precise measurement of (15)N-enriched NO in air. Furthermore, the analytical equipment developed greatly improves existing (15)N(2)O analysis using the GC-QMS technique. An application of the (15)N analysis method will be shown for an investigation on the NO and N(2)O formation in black earth soil after (15)NH(4)(+), (15)NO(3)(-) and (15)NO(2)(-) labelling. Copyright 1999 John Wiley & Sons, Ltd.

Journal Article↗
PubMed1986

Nitric Oxide and Nitrous Oxide Production by Soybean and Winged Bean during the in Vivo Nitrate Reductase Assay.

This study was conducted to determine by gas chromatography (GC) and mass spectrometry (MS) the identity and the quantity of volatile N products produced during the helium-purged in vivo NR assay of soybean (Glycine max [L.] Merr. cv Williams) and winged bean (Psophocarpus tetragonolobus [L.] DC. cv Lunita) leaflets. Gaseous material for identification and quantitation was collected by cryogenic trapping of volatile compounds carried in the He-purge gas stream. As opposed to an earlier report, acetaldehyde oxime production was not detected by our GC method, and acetaldehyde oxime was shown to be much more soluble in water than the compound(s) evolved from soybean leaflets. Nitric oxide (NO) and nitrous oxide (N(2)O) were identified by GC and GC/MS as the main N products formed. NO and N(2)O produced from soybean leaflets were both labeled with (15)N when (15)N-nitrate was used in the assay medium, demonstrating that both were produced from nitrate during nitrate reduction. Other compounds co-trapped with NO and N(2)O were identified as air (N(2), O(2)), CO(2), methanol, acetaldehyde, and ethanol. Leaves of winged bean, subjected to the purged in vivo NR assay, evolved greater quantities of NO and N(2)O (13.9 and 0.37 micromole per gram fresh weight per 30 minutes, respectively) than did the soybean cv Williams (1.67 and 0.09 micromole per gram fresh weight per 30 minutes, respectively). In both species NO production was dominant. In contrast, with similar assays, NO and N(2)O were not evolved from leaves of the nr(1) soybean mutant which lacks the constitutive NR enzymes. In addition to soybean cv Williams, six other Glycine sp. examined evolved significant quantities of NO((x)) (NO and NO(2)). Other species including Neonotonia wightii (Arn.) Lackey comb. nov., Pueraria montana (Lour.) Merr., and Pueraria thunbergiana Benth. evolved lower levels of NO((x)).

Journal Article↗
PubMed1994

Involvement of nitric oxide in nitrous oxide anxiolysis in the elevated plus-maze.

We recently reported that inhibition of nitric oxide (NO) production by the NO synthase (NOS) inhibitor L-NG-nitro arginine (L-NOARG) antagonized the behavioral effects of a benzodiazepine (BZ) in a mouse paradigm for screening anxiolytic drug activity. Because other research has found that the anesthetic gas nitrous oxide (N2O) also produces BZ-like behavioral effects, the present research was conducted to ascertain whether NO might also be involved in N2O anxiolysis. Male Swiss-Webster mice were tested in an elevated plus-maze inside an inflatable glovebag. Exposure to N2O significantly increased exploratory activity on the open arms of the plus-maze, as measured by the number of entries into the open arms and the time spent on the open arms. Pretreatment with L-NOARG significantly reduced the N2O-induced elevation in open arm activity. This antagonism of the N2O effect was reversed by ICV treatment of L-NOARG-pretreated mice with L-arginine but not D-arginine. These findings indicate that NO possibly mediates behavioral effects of N2O in an animal model for anxiety.

Amino Acid Oxidoreductases↗
PubMed1996

A comparison: the efficacy of sevoflurane-nitrous oxide or propofol-nitrous oxide for the induction and maintenance of general anesthesia.

STUDY OBJECTIVE: To compare sevoflurane-nitrous oxide with propofol-nitrous oxide for the induction and maintenance of anesthesia, and to determine the rates of recovery following each anesthetic. DESIGN: Randomized, controlled study. SETTING: Teaching hospital. PATIENTS: 50 ASA physical status I and II patients, ranging in age from 18 to 70 years. INTERVENTIONS: General anesthesia was induced with either sevoflurane or propofol and maintained with 60% to 70% nitrous oxide and either sevoflurane or a propofol infusion and supplemental fentanyl. At the conclusion of surgery, the oxygen flow was increased to 6 L/min and all anesthetics were discontinued simultaneously. Patients were monitored for the nature and speed of induction and emergency from anesthesia. MEASUREMENTS AND MAIN RESULTS: Induction of anesthesia was significantly slower in the sevoflurane group than in the propofol group (2.0 +/- 1.1 vs. 0.8 +/- 0.5 min, respectively). The ease of induction and the time required for emergence from anesthesia were the same in both study groups (eye opening: 9.0 +/- 4.4 min vs. 8.0 +/- 5.0 min; following commands: 11.2 +/- 5.0 min vs. 9.8 +/- 6.9 min; extubation: 9.1 +/- 4.5 min vs. 8.6 vs. 5.1 min in the sevoflurane and propofol groups, respectively). Patients in the sevoflurane group experienced nausea and vomiting more frequently than patients in the propofol group (13 and 5 patients vs. 3 and 0 patients in the sevoflurane and propofol groups, respectively), which were not related to the administration of neostigmine or intraoperative opioids. CONCLUSION: Sevoflurane allows for rapid inhalation induction of, and emergence from, general anesthesia.

Adolescent↗
PubMed1998

[Comparative study of sevoflurane and nitrous oxide versus halothane and nitrous oxide in pediatric anesthesia: efficacy and hemodynamic characteristics during induction].

OBJECTIVES: To study the efficacy, side effects and hemodynamics of anesthetic induction in pediatric patients using sevoflurane and nitrous oxide or halothane and nitrous oxide. PATIENTS AND METHODS: We studied 80 pediatric ASA I-II patients aged between 1 and 10 years old scheduled for infraumbilical surgery of short duration. The patients were randomly assigned to two groups of 40 to receive one of the two drug combinations. All the children were premedicated with nasal midazolam 0.2 mg.kg-1. Induction was by inhalation of increasing concentrations of sevoflurane or halothane. The maximum inspired concentration during induction was 7% for sevoflurane and 3% for halothane. We analyzed induction time, side effects and hemodynamic variables. RESULTS: The induction time was 2.06 +/- 0.5 min for halothane and 1.6 +/- 0.6 min for sevoflurane (p < 0.01). We observed no differences between the groups in coughing, laryngospasm, bronchospasm, secretions, apnea, nausea, vomiting, agitation or hiccoughing. Supraventricular beats appeared in 22.5% of patients in the halothane group and in 5% of the sevoflurane group. Induction with both anesthetics caused significant decreases from baseline blood pressure levels but no significant changes in heart rate. CONCLUSIONS: Inhaled sevoflurane in 60% nitrous oxide provides rapid but gentle anesthetic induction, with hemodynamic stability and a low incidence of airway complications. Sevoflurane is therefore a reasonable alternative to halothane for pediatric surgery.

Anesthesia, Inhalation↗