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).

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.

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

The Use of Sevoflurane in a 2:1 Mixture of Nitrous Oxide and Oxygen for Rapid Mask Induction of Anaesthesia in the Cat

2000 ◽  
Vol 2 (2) ◽  
pp. 83-90 ◽  
Author(s):  
S Tzannes ◽  
M Govendir ◽  
S Zaki ◽  
Y Miyake ◽  
P Packiarajah ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Gas Flow ◽  
Bone Marrow Aspiration ◽  
Face Mask ◽  
Blood Collection ◽  
Rapid Induction ◽  
Oxide Anaesthesia ◽  
Inhalational Technique ◽  
Therapeutic Procedures ◽  
Induction Of Anaesthesia

An inhalational technique for rapid induction of anaesthesia in unsedated cats using sevoflurane and nitrous oxide is described. Using a pliable, tight-fitting, face mask, sevoflurane (7.5–8%) was delivered from an out-of-circuit precision vaporiser connected to a coaxial non-rebreathing system using a fresh gas flow of 1 l oxygen and 2 l nitrous oxide per min. Cats were restrained with gentle but firm pressure applied by scruffing the dorsal cervical skin until the righting reflex was lost and the patient could be positioned in lateral recumbency. Typically, cats could be positioned on their side in a light plane of anaesthesia within 1 min of applying the mask, at which time the sevoflurane concentration was reduced to 5% or less. A similar protocol, using a lower initial concentration of sevoflurane, is recommended for old or debilitated patients. Maintenance of light sevoflurane (2–4%) anaesthesia by mask permitted minor interventions to be performed readily, including blood collection, intravenous chemotherapy, abdominal palpation, radiography and ultrasonography. More painful procedures, such as bone marrow aspiration, required a deeper plane of anaesthesia. Cats were sufficiently deep to be intubated, if this was required, about 3 min after commencing the induction. Recovery from sevoflurane/nitrous oxide anaesthesia was smooth and rapid, with most cats being able to right within 5 min of discontinuing the agents. This protocol for rapid inhalational induction and recovery is particularly suited to feline practice, where rendering an uncooperative patient unconscious greatly facilitates the completion of many minor diagnostic and therapeutic procedures, especially when these must be performed on successive days or when peripheral vascular access is limited. For longer procedures, isoflurane may be substituted for sevoflurane for maintenance of anaesthesia in order to minimise cost.

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.

Oxidation of propane with oxygen, nitrous oxide and oxygen/nitrous oxide mixture over Co- and Fe-zeolites

2005 ◽  
Vol 100 (3-4) ◽  
pp. 315-319 ◽  
Author(s):  
Kateřina Novoveská ◽  
Roman Bulánek ◽  
Blanka Wichterlová
Keyword(s):  
Nitrous Oxide ◽  
Oxide Mixture ◽  
Oxygen Nitrous Oxide

Continuous measurement of gas uptake and elimination in anesthetized patients using an extractable marker gas

2004 ◽  
Vol 97 (3) ◽  
pp. 960-966 ◽  
Author(s):  
Gavin J. B. Robinson ◽  
Philip J. Peyton ◽  
David Terry ◽  
Shiva Malekzadeh ◽  
Bruce Thompson
Keyword(s):  
Carbon Dioxide ◽  
Nitrous Oxide ◽  
Gas Flow ◽  
Continuous Measurement ◽  
Nitrogen Excretion ◽  
Gas Mixture ◽  
Colonic Surgery ◽  
Gas Uptake ◽  
Accuracy And Precision ◽  
Oxygen Nitrous Oxide

Measurement of pulmonary gas uptake and elimination is often performed, using nitrogen as marker gas to measure gas flow, by applying the Haldane transformation. Because of the inability to measure nitrogen with conventional equipment, measurement is difficult during inhalational anesthesia. A new method is described, which is compatible with any inspired gas mixture, in which fresh gas and exhaust gas flows are measured using carbon dioxide as an extractable marker gas. A system was tested in eight patients undergoing colonic surgery for automated measurement of uptake of oxygen, nitrous oxide, isoflurane, and elimination of carbon dioxide with this method. Its accuracy and precision were compared with simultaneous measurements made with the Haldane transformation and corrected for predicted nitrogen excretion by the lungs. Good agreement was obtained for measurement of uptake or elimination of all gases studied. Mean bias was −0.003 l/min for both oxygen and nitrous oxide uptake, −0.0002 l/min for isoflurane uptake, and 0.003 l/min for carbon dioxide elimination. Limits of agreement lay within 30% of the mean uptake rate for nitrous oxide, within 15% for oxygen, within 10% for isoflurane, and within 5% for carbon dioxide. The extractable marker gas method allows accurate and continuous measurement of gas uptake and elimination in an anesthetic breathing system with any inspired gas mixture.

Induction of Anesthesia and Tracheal Intubation with Sevoflurane in Adults

1996 ◽  
Vol 85 (3) ◽  
pp. 536-543. ◽  
Author(s):  
M. Muzi ◽  
B.J. Robinson ◽  
T.J. Ebert ◽  
T.J. O'Brien
Keyword(s):  
Nitrous Oxide ◽  
Laryngeal Mask Airway ◽  
Tracheal Intubation ◽  
Gas Flow ◽  
Face Mask ◽  
Laryngeal Mask ◽  
Breath Holding ◽  
Laryngeal Mask Airway Insertion ◽  
Airway Responses ◽  
To Receive

Background The speed, quality, and cost of mask induction of anesthesia and laryngeal mask airway insertion or tracheal intubation were studied in young non-premedicated volunteers given high inspired concentrations of sevoflurane (6 to 7%). Methods Twenty healthy persons who were 19 to 32 years old participated three times, received 6 l/min fresh gas flow, and were randomized to receive 6 to 7% sevoflurane in 66% nitrous oxide/28% oxygen by face mask until tracheal intubation (treatment 1) or until laryngeal mask airway insertion (treatment 3), or 6 to 7% sevoflurane without nitrous oxide to tracheal intubation (treatment 2). Participants exhaled to residual volume and took three vital capacity breaths of the gas mixture; thereafter ventilation was manually assisted. The time of exposure to the inhaled gas was varied for consecutive participants. It was either increased or decreased by 30-sec increments based on the failure or success of the preceding volunteer's response to laryngoscopy and intubation after a preselected exposure time. Failure was defined as poor jaw relaxation, coughing or bucking, or inadequate vocal cord relaxation. Results Loss of the lid-lash reflex in unpremedicated young volunteers was achieved in 1 min and did not differ among groups. Average time (and 95% confidence interval) for acceptable conditions for LMA insertion was achieved in 1.7 (0.7 to 2.7) min, and all participants had an immediate return of spontaneous ventilation. The time for acceptable tracheal intubating conditions after manual hyperventilation by mask was 4.7 (3.7 to 5.7) min and 6.4 (5.1 to 7.7) min in treatments 1 and 2, respectively. There were no cases of increased secretions or laryngospasm. The incidence of breath holding and expiratory stridor ("crowing") was 7.5% and 25%, respectively, during treatment 1 and 15% and 40%, respectively, during treatment 2. Conclusions The induction of anesthesia to loss of lid reflex in young non-premedicated adults approaches the speed of intravenous induction techniques. No untoward airway responses were noted during mask induction of anesthesia with a three-breath technique. In response to intubation, no adverse airway responses, including jaw tightness, laryngospasm, and excessive coughing or bucking, occurred in participants whose duration of mask administration of sevoflurane met the appropriate times (as determined in this study).

Instrument for Continuous Measurement of O2 Consumption and CO2 Production of Men in Hyperbaric Chambers

1978 ◽  
Vol 100 (1) ◽  
pp. 1-6 ◽  
Author(s):  
S. J. Troutman ◽  
P. Webb
Keyword(s):  
Face Mask ◽  
Ventilation Rate ◽  
Open Circuit ◽  
Co2 Production ◽  
O2 Consumption ◽  
Douglas Bag ◽  
Clear Plastic ◽  
The Subject ◽  
Full Face ◽  
Chamber Gas

We describe an open circuit method for measuring O2 consumption and CO2 production suitable for use in hyperbaric atmospheres and designed to yield continuous data while allowing the critical instrumentation to remain outside the hyperbaric chamber. The subject wears a light, loosely fitting, full face mask of clear plastic, through which ambient chamber gas is drawn at either 100 l/min for rest or sleep, or 200 l/min during exercise. Samples of the chamber gases and of the mixed expired gases are bled out of the chamber, then compared in differential analyzers. The analog signals from the analyzers are conditioned, proportioned to the mask ventilation rate, totalized and integrated to yield gas volumes, then printed every 10 min. A method of calibrating the system using inflows of pure CO2 was devised for use at 1 atm absolute and also at hyperbaric pressures. Data taken by this method during a 17-day saturation dive compared well to the data obtained using conventional Douglas bag techniques.

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