Inspired Oxygen and Nitrous Oxide Concentrations in Volunteers during Nitrous Oxide Sedation with a Hudson Mask

1988 ◽  
Vol 16 (4) ◽  
pp. 423-426 ◽  
Author(s):  
B. J. Anderson ◽  
A. Dyson ◽  
A. M. Henderson
Keyword(s):  
Nitrous Oxide ◽  
Variable Amount ◽  
Oxygen Levels ◽  
Oxygen Fraction ◽  
Carbon Dioxide Concentrations ◽  
End Tidal Carbon Dioxide ◽  
Oxide Concentration ◽  
End Tidal ◽  
Nitrous Oxide Concentration ◽  
Inspired Oxygen

Ten volunteers were given varying ratios of oxygen and nitrous oxide at 4,6 and 8 litres per minute using a Hudson mask delivery system. Maximum and minimum inspired oxygen concentrations, maximum inspired nitrous oxide concentrations and end tidal carbon dioxide concentrations were measured using the Datex Cardiocap CCI-104 monitor. Although pharyngeal oxygen fraction varies with the Hudson mask because the inspiratory flow exceeds the entrainment of the mask by a variable amount during much of the cycle, at 8 litres/minute flow with a ratio of 3 to 5, oxygen to nitrous oxide, safe levels of oxygen were delivered (range of means 26–31%) with basal nitrous oxide levels (mean maximum inspired N 2 O, 34%). When nitrous oxide sedation is used clinically, nitrous oxide must be used with consideration of safe oxygen levels. This study did not detect unsafe pharyngeal oxygen levels in the ratios investigated, where the maximum delivered nitrous oxide concentration was 75%.

scholarly journals Effect of dietary crude protein modification on ammonia and nitrous oxide concentration on a tie-stall dairy barn floor

2010 ◽  
Vol 93 (7) ◽  
pp. 3158-3165 ◽  
Author(s):  
H. Arriaga ◽  
G. Salcedo ◽  
L. Martínez-Suller ◽  
S. Calsamiglia ◽  
P. Merino
Keyword(s):  
Nitrous Oxide ◽  
Crude Protein ◽  
Protein Modification ◽  
Dietary Crude Protein ◽  
Oxide Concentration ◽  
Nitrous Oxide Concentration

Interaction of Isoflurane and Nitrous Oxide Combinations Similar for Median Electroencephalographic Frequency and Clinical Anesthesia

1996 ◽  
Vol 84 (4) ◽  
pp. 782-788. ◽  
Author(s):  
Heiko Ropcke ◽  
Helmut Schwilden
Keyword(s):  
Nitrous Oxide ◽  
Minimum Alveolar Concentration ◽  
Dose Range ◽  
Volatile Anesthetic ◽  
Oxide Concentration ◽  
Anesthetic Requirement ◽  
Clinical Anesthesia ◽  
Sparing Effect ◽  
The Relationship ◽  
Nitrous Oxide Concentration

Background The volatile anesthetic sparing effect of nitrous oxide in clinical studies is less than might be expected from the additivity of minimum alveolar concentration values. Other studies identify nonadditive interactions between isoflurane and nitrous oxide. The aim of this study was to quantify the interaction of isoflurane and nitrous oxide at a constant median electroencephalographic frequency. Methods Twenty-five patients were studied during laparotomies. Nitrous oxide was randomly administered in concentrations of 0, 20, 40, 60, and 75 vol%, to ten patients for each nitrous oxide concentration. Isoflurane vaporizer settings were chosen so that the median electroencephalographic frequency was held between 2 and 3 Hz. The relationship between nitrous oxide concentrations and required isoflurane concentrations was examined with the method of isoboles. Results Nitrous oxide linearly decreased the isoflurane requirement. Addition of every 10 vol% of nitrous oxide decreases the isoflurane requirement by approximately 0.04 vol%. The total anesthetic requirement of isoflurane and nitrous oxide, expressed in terms of previously reported minimum alveolar concentration values, increased significantly with increasing nitrous oxide concentrations. Conclusions The interaction of isoflurane and nitrous oxide in the dose range 0-75 vol% on median electroencephalographic frequency is compatible with additivity. The potency of nitrous oxide as a substitute for isoflurane is less than on a minimum alveolar concentration basis. Maintaining median electroencephalographic frequency more appropriately reflects the clinical usage of isoflurane and nitrous oxide than does maintaining minimum alveolar concentration.

scholarly journals Relationship Between Salivary Nitric Oxide Concentration and Dental Caries in Children: A Systematic Review and Meta-Analysis

2020 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Nadia Elyassi ◽  
Ali Malekzadeh Shafaroudi ◽  
Pegah Nasiri ◽  
Mahmood Moosazadeh ◽  
Azam Nahvi
Keyword(s):  
Nitric Oxide ◽  
Nitrous Oxide ◽  
Dental Caries ◽  
Meta Analysis ◽  
Control Group ◽  
Analysis Study ◽  
Oxide Concentration ◽  
The Mean ◽  
The Relationship ◽  
Nitrous Oxide Concentration

Context: Conflicting results have been reported in the literature concerning the relationship between salivary nitrous oxide concentration and dental caries in children. Metaanalysis studies aim to combine different studies and reduce the difference between the parameters by increasing the number of studies involved in the analysis process. Objectives: Accordingly, this meta-analysis study aimed at determining the relationship between salivary nitrous oxide concentration and dental caries in children. Methods: Databases were searched using the keywords “nitric oxide”, “salivary”, “Caries”, “DMFT Index”, “children”, “early childhood caries” and OR, AND and NOT operators. Quality assessment was then performed based on the Newcastle-Ottawa scale (NOS) checklist. The standardized mean difference (SMD) of DMFT, dmft, and salivary nitric oxide (NO) concentration was estimated. Results: Seven studies made a comparison between the mean salivary NO concentration in children with dental caries and that in the control group. In four studies, the mean salivary NO concentration in children with dental caries was lower, as compared to that in the control group. This difference was significant in all four studies. Also, the mean standardized difference of the salivary NO index was also estimated to be -0.11 (CI 95%: -1.77, 1.55). Conclusions: This meta-analysis study demonstrated that salivary NO concentration was not significantly related to dental caries. Moreover, since salivary NO concentration is affected by various factors, it is not sufficient to determine the likelihood of the incidence of caries.

scholarly journals An Oxygen Failure Warning and Patient Protection System. The Howison Unit

1978 ◽  
Vol 6 (1) ◽  
pp. 71-74 ◽  
Author(s):  
C. McK. Holmes
Keyword(s):  
Nitrous Oxide ◽  
Oxygen Supply ◽  
Protection System ◽  
Oxygen Flow ◽  
Oxygen Levels ◽  
Patient Protection ◽  
Inspired Oxygen

A device is described which sounds an alarm to warn of oxygen supply failure. A the same time the nitrous oxide flow is cut off, and a reservoir in the device provides a continuing oxygen flow to the patient for about a minute. This results in increased inspired oxygen levels temporarily, reducing the risk to the patient while the oxygen failure is being corrected.

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.

Reinforcing effects of extended inhalation of a low nitrous oxide concentration in humans

1993 ◽  
Vol 46 (4) ◽  
pp. 927-932 ◽  
Author(s):  
Cathleen S. Dohrn ◽  
J.Lance Lichtor ◽  
Dennis W. Coalson ◽  
David Flemming ◽  
James P. Zacny
Keyword(s):  
Nitrous Oxide ◽  
Oxide Concentration ◽  
Reinforcing Effects ◽  
Nitrous Oxide Concentration
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