Effect of N2O on Sevoflurane Vaporizer Settings during Minimal- and Low-flow Anesthesia

2002 ◽  
Vol 97 (2) ◽  
pp. 400-404 ◽  
Author(s):  
Jan F. A. Hendrickx ◽  
José Coddens ◽  
Frederik Callebaut ◽  
Hermes Artico ◽  
Thierry Deloof ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Gas Flow ◽  
Low Flow ◽  
Oxide Mixture ◽  
Factors Affecting ◽  
Carrier Gas ◽  
Dial Setting ◽  
Oxygen Nitrous Oxide ◽  
Low Flow Anesthesia ◽  
Almost All

Background Uptake of a second gas of a delivered gas mixture decreases the amount of carrier gas and potent inhaled anesthetic leaving the circle system through the pop-off valve. The authors hypothesized that the vaporizer settings required to maintain constant end-expired sevoflurane concentration (Etsevo) during minimal-flow anesthesia (MFA, fresh gas flow of 0.5 l/min) or low-flow anesthesia (LFA, fresh gas flow of 1 l/min) would be lower when sevoflurane is used in oxygen-nitrous oxide than in oxygen. Methods Fifty-six patients receiving general anesthesia were randomly assigned to one of four groups (n = 14 each), depending on the carrier gas and fresh gas flow used: group Ox.5 l (oxygen, MFA), group NOx.5 l (oxygen-nitrous oxide, MFA after 10 min high fresh gas flow), group Ox1 l (oxygen, LFA), and group NOx1 l (oxygen-nitrous oxide, LFA after 10 min high fresh gas flow). The vaporizer dial settings required to maintain Etsevo at 1.3% were compared between groups. Results Vaporizer settings were higher in group Ox.5 l than in groups NOx.5 l, Ox1 l, and NOx1 l; vaporizer settings were higher in group NOx.5 l than in group NOx1 l between 23 and 47 min, and vaporizer settings did not differ between groups Ox1 l and NOx1 l. Conclusions When using oxygen-nitrous oxide as the carrier gas, less gas and vapor are wasted through the pop-off valve than when 100% oxygen is used. During MFA with an oxygen-nitrous oxide mixture, when almost all of the delivered oxygen and nitrous oxide is taken up by the patient, the vaporizer dial setting required to maintain a constant Etsevo is lower than when 100% oxygen is used. With higher fresh gas flows (LFA), this effect of nitrous oxide becomes insignificant, presumably because the proportion of excess gas leaving the pop-off valve relative to the amount taken up by the patient increases. However, other unexplored factors affecting gas kinetics in a circle system may contribute to our observations.

scholarly journals Halothane anaesthesia of normal and dystrophic hamsters

1975 ◽  
Vol 9 (4) ◽  
pp. 345-352 ◽  
Author(s):  
J. E. Carvell ◽  
P. J. Stoward
Keyword(s):  
Nitrous Oxide ◽  
Gas Flow ◽  
Face Mask ◽  
Open Circuit ◽  
Dystrophic Muscle ◽  
Oxide Mixture ◽  
Oxygen Nitrous Oxide ◽  
Wet Weight ◽  
Clear Plastic ◽  
Anaesthetic Mixture

Induction, carried out in a small clear-plastic box with 3·5% (v/v) halothane in 30:70 (v/v) oxygen: nitrous oxide, was quiet and rapid. Recovery was almost instantaneous. 2% halothane in the oxygen-nitrous oxide mixture was sufficient for maintenance anaesthesia. The anaesthetic mixture was given by face mask in an open circuit specially designed to function at low gas-flow rates. The halothane content of the muscle and blood after 25 min anaesthesia was estimated by gas chromatography of n-heptane extracts. The mean level(± s.e.m.) in blood was 22·8±2·7 mg/1OO ml (n=4), and in dystrophic muscle 226±36·8 mg/100 g wet weight of tissue (n=4): there was a positive correlation (r=0·94) between them ( p<:0·02).

scholarly journals 1-1-8 one-step sevoflurane-nitrous oxide wash-in scheme for low-flow anesthesia: simple, rapid, and predictable induction

2019 ◽  
Author(s):  
Sirirat Tribuddharat ◽  
Thepakorn Sathitkarnmanee ◽  
Naruemon Vattanasiriporn ◽  
Maneerat Thananun ◽  
Duangthida Nonlhaopol ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Gas Flow ◽  
Low Flow ◽  
Gas Analyzer ◽  
Controlled Ventilation ◽  
End Tidal Carbon Dioxide ◽  
One Step ◽  
Low Flow Anesthesia ◽  
Carbon Dioxide Co2 ◽  
End Tidal

Abstract Background Sevoflurane is suitable for low-flow anesthesia (LFA). LFA needs a wash-in phase. The reported sevoflurane wash-in schemes lack simplicity, target coverage, and applicability. We proposed a one-step 1-1-8 wash-in scheme for sevoflurane-nitrous oxide (N2O) LFA. The objective of our study was to identify times to achieve every alveolar concentration of sevoflurane (FAS) from 1% to 3.5%. Methods We recruited 102 adults requiring general anesthesia with endotracheal intubation and controlled ventilation. After induction and intubation, a wash-in was started using a fresh gas flow of oxygen (O2):N2O at 1:1 L·min-1 plus sevoflurane 8%. The ventilation was controlled to maintain end-tidal carbon dioxide (CO2) of 30-35 mmHg. Results The rising patterns of FAS and inspired concentration of sevoflurane (FIS) are similar and parallel. The FAS/FIS ratio increased from 0.46 to 0.72 within 260 sec. The respective times to achieve FAS of 1%, 1.5%, 2%, 2.5%, 3% and 3.5% were 1, 1.5, 2, 3, 3.5, and 4.5 min. The heart rate and blood pressure significantly increased initially then gradually decreased as FAS increased. Conclusions The 1-1-8 wash-in scheme for sevoflurane has many advantages, including simplicity, coverage, swiftness, safety, and economy. A respective FAS of 1%, 1.5%, 2%, 2.5%, 3%, and 3.5% can be expected at 1, 1.5, 2, 3, 3.5, and 4.5 min. This scheme may be applied for LFA in the situation where anesthetic gas analyzer is not available.

scholarly journals 1-1-12 One-Step Wash-In Scheme for Desflurane-Nitrous Oxide Low-Flow Anesthesia: Rapid and Predictable Induction

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Thepakorn Sathitkarnmanee ◽  
Sirirat Tribuddharat ◽  
Chakthip Suttinarakorn ◽  
Duangthida Nonlhaopol ◽  
Maneerat Thananun ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Nitrous Oxide ◽  
Gas Flow ◽  
Elective Surgery ◽  
Low Flow ◽  
One Step ◽  
Low Flow Anesthesia ◽  
Clinically Significant ◽  
Linear Manner

Background. We propose a 1-1-12 wash-in scheme for desflurane-nitrous oxide (N2O) low-flow anesthesia. The objective of our study was to determine the time to achieve alveolar concentration of desflurane (FAD) at 1, 2, 3, 4, 5, and 6%.Methods. We enrolled 106 patients scheduled for elective surgery under general anesthesia. After induction and intubation, wash-in was started with a fresh gas flow (FGF) of N2O : O21 : 1 L min−1and vaporizer concentration of desflurane (FD) of 12%. Ventilation was controlled to maintainPACO2at 30–35 mmHg.Results. TheFADrose rapidly from 0 to 4% in 2 min in a linear manner in 0.5 min increments. AnFADof 6% was achieved in 4 min in a linear fashion fromFADof 4% but in 1 min increments. AnFADof 1 to 6% occurred at 0.6, 1, 1.5, 2, 3, and 4 min. Heart rate during wash-in showed a statistically, albeit not clinically, significant pattern of increase. By contrast, blood pressure slightly decreased during this period.Conclusions. We developed a 1-1-12 wash-in scheme using a FGF of N2O : O21 : 1 L min−1and FD of 12% for desflurane-nitrous oxide low-flow anesthesia. A respectiveFADof 1, 2, 3, 4, 5, and 6% can be expected at 0.6, 1, 1.5, 2, 3, and 4 min.

scholarly journals High Flow Closed Circuit Anaesthesia

1994 ◽  
Vol 22 (4) ◽  
pp. 426-434 ◽  
Author(s):  
A. P. K. Verkaaik ◽  
G. Van Dijk
Keyword(s):  
Nitrous Oxide ◽  
Time Constant ◽  
Gas Flow ◽  
High Flow ◽  
Controlled Delivery ◽  
Closed Circuit ◽  
Clinical Use ◽  
Volatile Anaesthetics ◽  
Carrier Gas ◽  
Flow Systems

We present an automatic closed circuit anaesthesia ventilator designed for routine clinical use. The ventilator combines the benefits of high flow systems and true closed circuits, without their disadvantages. The system can be used with any FiO2, with air or nitrous oxide as carrier gas. Servo controlled delivery of modern volatile anaesthetics is regulated on endtidal value. The time constant for increase or decrease of concentrations is only a few minutes. There is no need to open the system at any time, nor is it necessary to increase the fresh gas flow. An automatic flush procedure prevents accumulation of unwanted gases. Operation is as easy as contemporary non-closed circuit ventilators. With this machine, closed circuit anaesthesia is possible from the beginning to the end of the procedure.

The ideal oxygen/nitrous oxide fresh gas flow sequence with the Anesthesia Delivery Unit machine

2007 ◽  
Vol 19 (4) ◽  
pp. 274-279 ◽  
Author(s):  
Jan F.A. Hendrickx ◽  
Sara Cardinael ◽  
Rik Carette ◽  
Hendrikus J.M. Lemmens ◽  
Andre M. De Wolf
Keyword(s):  
Nitrous Oxide ◽  
Gas Flow ◽  
Oxygen Nitrous Oxide ◽  
Delivery Unit ◽  
The Ideal

scholarly journals 1-1-8 one-step sevoflurane wash-in scheme for low-flow anesthesia: simple, rapid, and predictable induction

2019 ◽  
Author(s):  
Sirirat Tribuddharat ◽  
Thepakorn Sathitkarnmanee ◽  
Naruemon Vattanasiriporn ◽  
Maneerat Thananun ◽  
Duangthida Nonlhaopol ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Gas Flow ◽  
Low Flow ◽  
Target Coverage ◽  
Gas Analyzer ◽  
Controlled Ventilation ◽  
One Step ◽  
Low Flow Anesthesia ◽  
End Tidal

Abstract Background Sevoflurane is suitable for low-flow anesthesia (LFA). LFA needs a wash-in phase. The reported sevoflurane wash-in schemes lack simplicity, target coverage, and applicability. We proposed a one-step 1-1-8 wash-in scheme for sevoflurane LFA to be used with both N 2 O and Air. The objective of our study was to identify time for achieving each level of alveolar concentration of sevoflurane (F A S) from 1% to 3.5% in both contexts.Methods We recruited 199 adults requiring general anesthesia with endotracheal intubation and controlled ventilation—102 in group N 2 O and 97 in group Air. After induction and intubation, a wash-in was started using a fresh gas flow of O 2 :N 2 O or O 2 :Air at 1:1 L·min -1 plus sevoflurane 8%. The ventilation was controlled to maintain end-tidal CO 2 of 30-35 mmHg.Results The rising patterns of F A S and inspired concentration of sevoflurane (F I S) are similar, running parallel between the groups. The F A S/F I S ratio increased from 0.46 to 0.72 within 260 sec in group N 2 O and from 0.42 to 0.69 within 286 sec in group Air. The respective time to achieve an F A S of 1%, 1.5%, 2%, 2.5%, 3%, and 3.5% was 1, 1.5, 2, 3, 3.5, and 4.5 min in group N 2 O and 1, 1.5, 2, 3, 4, and 5 min in group Air. The heart rate and blood pressure of both groups significantly increased initially then gradually decreased as F A S increased.Conclusions The 1-1-8 wash-in scheme for sevoflurane LFA has many advantages, including simplicity, coverage, swiftness, safety, economy, and that it can be used with both N 2 O and Air. A respective F A S of 1%, 1.5%, 2%, 2.5%, 3%, and 3.5% when used with N 2 O and Air can be expected at 1, 1.5, 2, 3, 3.5, and 4.5 min and 1, 1.5, 2, 3, 4, and 5 min. This scheme may be applied for sevoflurane LFA in situations where an anesthetic gas analyzer is unavailable.

scholarly journals The Effects of Nitrous Oxide on Controlled Hypotension During Low Flow Anesthesia

2013 ◽  
Vol 63 (2) ◽  
pp. 170-177
Author(s):  
Semiha Barçın ◽  
Leyla Sahan ◽  
Dilsen Ornek ◽  
Fazilet Sahin ◽  
Oya Kilci ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Low Flow ◽  
Controlled Hypotension ◽  
Low Flow Anesthesia

Influence of Anesthetics—Nitrous Oxide in Particular—on Electromyographic Response Evoked by Transcranial Electrical Stimulation of the Cortex

Neurosurgery ◽  
1989 ◽  
Vol 24 (2) ◽  
pp. 253-256 ◽  
Author(s):  
Josef Zentner ◽  
Ivan Kiss ◽  
Alois Ebner
Keyword(s):  
Nitrous Oxide ◽  
Motor Evoked Potentials ◽  
Transcranial Electrical Stimulation ◽  
Minor Effect ◽  
Oxide Mixture ◽  
Similar Reduction ◽  
Anterior Tibial ◽  
Oxygen Nitrous Oxide ◽  
A Minor ◽  
Electrical Stimuli

Abstract The influence of anesthetics usually used for neuroleptic anesthesia—nitrous oxide, fetanyl, flunitrazepam, and thiopental sodium—on motor evoked potentials (MEP) was examined in 15 patients during neurosurgical operations on the spinal cord, in 16 patients in traumatic coma, and in 6 healthy volunteers. MEP were recorded from the contralateral thenar and anterior tibial muscles in response to single transcranial electrical stimuli on the motor cortex. Intraoperatively, during neuroleptic anesthesia we found the amplitudes to be reduced to an average of 11% of the preoperative baselines for the thenar potentials, and to 7% of the preoperative baselines for the anterior tibial muscle potentials, despite a maximum stimulus strength of 750 V. A similar reduction of MEP amplitudes was observed in 6 volunteers during breathing of an oxygen/nitrous oxide mixture (34%/66%), whereas fentanyl, flunitrazepam, and thiopental had only a minor effect on MEP. We conclude that with respect to anesthesia-related suppression of amplitudes, an average of 5 to 15 electromyographic responses should be evaluated for intraoperative monitoring of MEP using the technique described here.

scholarly journals 1-1-8 one-step sevoflurane wash-in scheme for low-flow anesthesia: simple, rapid, and predictable induction

2019 ◽  
Author(s):  
Sirirat Tribuddharat ◽  
Thepakorn Sathitkarnmanee ◽  
Naruemon Vattanasiriporn ◽  
Maneerat Thananun ◽  
Duangthida Nonlhaopol ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Gas Flow ◽  
Low Flow ◽  
Target Coverage ◽  
Gas Analyzer ◽  
Controlled Ventilation ◽  
One Step ◽  
Low Flow Anesthesia ◽  
End Tidal

Abstract Background Sevoflurane is suitable for low-flow anesthesia (LFA). LFA needs a wash-in phase. The reported sevoflurane wash-in schemes lack simplicity, target coverage, and applicability. We proposed a one-step 1-1-8 wash-in scheme for sevoflurane LFA to be used with both N 2 O and Air. The objective of our study was to identify time for achieving each level of alveolar concentration of sevoflurane (F A S) from 1% to 3.5% in both contexts.Methods We recruited 199 adults requiring general anesthesia with endotracheal intubation and controlled ventilation—102 in group N 2 O and 97 in group Air. After induction and intubation, a wash-in was started using a fresh gas flow of O 2 :N 2 O or O 2 :Air at 1:1 L·min -1 plus sevoflurane 8%. The ventilation was controlled to maintain end-tidal CO 2 of 30-35 mmHg.Results The rising patterns of F A S and inspired concentration of sevoflurane (F I S) are similar, running parallel between the groups. The F A S/F I S ratio increased from 0.46 to 0.72 within 260 sec in group N 2 O and from 0.42 to 0.69 within 286 sec in group Air. The respective time to achieve an F A S of 1%, 1.5%, 2%, 2.5%, 3%, and 3.5% was 1, 1.5, 2, 3, 3.5, and 4.5 min in group N 2 O and 1, 1.5, 2, 3, 4, and 5 min in group Air. The heart rate and blood pressure of both groups significantly increased initially then gradually decreased as F A S increased.Conclusions The 1-1-8 wash-in scheme for sevoflurane LFA has many advantages, including simplicity, coverage, swiftness, safety, economy, and that it can be used with both N 2 O and Air. A respective F A S of 1%, 1.5%, 2%, 2.5%, 3%, and 3.5% when used with N 2 O and Air can be expected at 1, 1.5, 2, 3, 3.5, and 4.5 min and 1, 1.5, 2, 3, 4, and 5 min. This scheme may be applied for sevoflurane LFA in situations where an anesthetic gas analyzer is unavailable.

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