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Annabel J. Bigley - One of the best experts on this subject based on the ideXlab platform.

  • Determination of the Minimal Fresh Gas Flow to Maintain a Therapeutic Inspired Oxygen Concentration in a Semi-Closed Anesthesia Circle System Using an Oxygen Concentrator as the Oxygen Source
    2001
    Co-Authors: Joan T. Grano, Andrea L. Roberts, Annabel J. Bigley
    Abstract:

    Abstract : The purpose of this study was to determine the rate of oxygen dilution, resulting from argon accumulation, using 3 low fresh gas flow rates using an oxygen concentrator in a semi-closed anesthesia circle system. This was a prospective, non-experimental descriptive designed study. Nine subjects participated in 3 trials each of fresh gas flows (0.5 liter, 1 liter, and 2 liters) from the oxygen concentrator, with the order counterbalanced, for a total of 27 trials. Preoxygenation and denitrogenation were done prior to the trial beginning. Inspiratory and expiratory gases were measured directly for oxygen, Carbon Dioxide, and nitrogen; and indirectly for argon. The expiratory gases passed through a Carbon Dioxide Absorber in the circle system prior to entering the inspiratory limb. Continuous monitoring of inspiratory and expiratory gas concentrations was done, including 5 minute recordings. Continuous monitoring of oxygen saturation,respiratory status, and electrocardiogram was done, with 10 minute recordings including blood pressure. A one-way repeated measures ANOVA was used to determine the differences of the inspired oxygen concentration at baseline, 15 minutes, and 30 minutes between subjects for the 3 different flow rates. Data analysis showed a statistically significant difference in inspired oxygen concentration between 0.5 and 1 liter per minute, and between 0.5 and 2 liters per minute. There was not a significant difference between 1 and 2 liters per minute. A statistically significant difference across all three flow rates in inspired concentrations of oxygen (p

  • determination of the minimal fresh gas flow to maintain a therapeutic inspired oxygen concentration in a semi closed anesthesia circle system using an oxygen concentrator as the oxygen source
    2001
    Co-Authors: Joan T. Grano, Andrea L. Roberts, Annabel J. Bigley
    Abstract:

    Abstract : The purpose of this study was to determine the rate of oxygen dilution, resulting from argon accumulation, using 3 low fresh gas flow rates using an oxygen concentrator in a semi-closed anesthesia circle system. This was a prospective, non-experimental descriptive designed study. Nine subjects participated in 3 trials each of fresh gas flows (0.5 liter, 1 liter, and 2 liters) from the oxygen concentrator, with the order counterbalanced, for a total of 27 trials. Preoxygenation and denitrogenation were done prior to the trial beginning. Inspiratory and expiratory gases were measured directly for oxygen, Carbon Dioxide, and nitrogen; and indirectly for argon. The expiratory gases passed through a Carbon Dioxide Absorber in the circle system prior to entering the inspiratory limb. Continuous monitoring of inspiratory and expiratory gas concentrations was done, including 5 minute recordings. Continuous monitoring of oxygen saturation,respiratory status, and electrocardiogram was done, with 10 minute recordings including blood pressure. A one-way repeated measures ANOVA was used to determine the differences of the inspired oxygen concentration at baseline, 15 minutes, and 30 minutes between subjects for the 3 different flow rates. Data analysis showed a statistically significant difference in inspired oxygen concentration between 0.5 and 1 liter per minute, and between 0.5 and 2 liters per minute. There was not a significant difference between 1 and 2 liters per minute. A statistically significant difference across all three flow rates in inspired concentrations of oxygen (p <0.0001), argon (p <0.0001), and nitrogen (p <0.0001) were seen. There is a statistically and clinically significant increase in oxygen dilution, and argon and nitrogen accumulation at the low flow rate of 0.5 liter per minute.

V. V. Donskikh - One of the best experts on this subject based on the ideXlab platform.

Stefano Fusetti - One of the best experts on this subject based on the ideXlab platform.

  • Obstruction due to retained Carbon Dioxide Absorber canister wrapping.
    Anesthesia and analgesia, 1996
    Co-Authors: Peter H. Norman, M. Denise Daley, James R. Walker, Stefano Fusetti
    Abstract:

    Proper functioning of every item of anesthetic equipment is of utmost importance in ensuring the safety of modern-day anesthesia. Accordingly, guidelines have been developed by several regulatory agencies for the safe manufacturing and use of most equipment used in anesthesia. As well, the Food and Drug Administration (FDA) has developed recommendations to test the integrity of all anesthetic apparatus prior to use (1). However, mishaps due to equipment failure still occur. Here we describe a case of breathing circuit obstruction due to failure to remove the packaging from a CO, Absorber canister.

D. H. T. Scott - One of the best experts on this subject based on the ideXlab platform.

  • Performance characteristics of a 'to and fro' disposable soda lime canister.
    Anaesthesia, 1998
    Co-Authors: M. Shaw, D. H. T. Scott
    Abstract:

    The performance of the Intersurgical disposable soda lime canister was compared to British Pharmacopoeia standards for Carbon Dioxide absorption and to other Carbon Dioxide Absorber systems. This canister system more than adequately fulfilled the equivalent of the British Pharmacopoeia standard for CO2 absorption. It performed efficiently for over 3 h of continuous use, absorbing 200 mlmin−1 at varying combinations of tidal volume and ventilation rate. Efficiency was not dependent on close matching of tidal volume with canister volume and there was no channelling of gases. Heat was generated by the reaction between soda lime and CO2 and the maximum temperature recorded in the system was 42.1 °C. Under clinical conditions this should pose no threat of thermal injury to the patient.

Anders Johansson - One of the best experts on this subject based on the ideXlab platform.

  • Modern inhalation agents and effects of anaesthesia equipment during low-flow anaesthesia
    2003
    Co-Authors: Anders Johansson
    Abstract:

    Volatile agents are economically and ecologically acceptable only when administered via low-flow systems. However, sevoflurane degrades during low-flow anaesthesia to compound A, and a high Carbon Dioxide Absorber temperature increases this degradation. This thesis suggests that there is a correlation between apparatus dead-space volume and Absorber temperature during low- and minimal-flow sevoflurane anaesthesia. Increasing the dead-space volume reduces Absorber temperature during low- and minimal-flow sevoflurane anaesthesia. The main disadvantage of low-flow techniques is that inspired (In) and end-tidal (Et) anaesthetic agent concentrations are not directly related to the vaporiser setting. In the present studies, with desflurane and sevoflurane, there was a significant difference between Et and In concentrations at fresh gas flows (FGFs) of 1.0 and 2.0 l/min. However, the ratio of Et to In concentration remained fairly constant. Excessive respiratory heat loss may lower body temperature. Artificial humidification of dry inspired gases reduces loss of body heat during anaesthesia, hence the popularity of heat and moisture exchangers (HMEs). In this study, HMEs improved the humidity of the anaesthetic gases at different FGFs, but did not improve maintenance of body temperature during low-flow anaesthesia in adults undergoing elective general or urologic surgery.

  • Soda lime temperatures during low-flow sevoflurane anaesthesia and differences in dead-space
    Acta anaesthesiologica Scandinavica, 2002
    Co-Authors: Hans-henrik Luttropp, Anders Johansson
    Abstract:

    BACKGROUND: Sevoflurane degrades during low-flow anaesthesia to compound A, and high Carbon Dioxide absorbent temperatures cause increased degradation. The purpose of this investigation was to determine if larger tidal volumes, without increasing alveolar ventilation, decrease the temperature in the Carbon Dioxide Absorber during low- and minimal-flow sevoflurane anaesthesia. METHODS: Prospective, randomized study, including 45 patients (ASA 1-2), scheduled for elective general or urology surgery. The patients were randomly assigned to one of three treatments. Patients in group 1 (NDS) received fresh gas flow of 1 litre/min without using additional dead-space volumes. In group 2 (DS + 1.0), the patients received fresh gas flow of 1 litre/min using additional dead-space volumes, placed between the Y-piece and the HME, and patients in group 3 (DS + 0.5) received the same technique with a fresh gas flow of 0.5 litre/min. The soda lime temperatures, dead-space volumes, end-tidal Carbon Dioxide, sevoflurane concentrations, ventilation volumes and pressures, absorbent weight and ear temperatures were measured. RESULTS: The maximum temperature of the soda lime was 44.1 +/- 1.1 degrees C in the NDS group, 37.8 +/- 0.8 degrees C in the DS + 1.0 group and 38.5 +/- 2.7 degrees C in the DS + 0.5 group (P