Measurement of systemic oxygen uptake during low‐flow anaesthesia with a standard technique vs. a novel method

Leonard, Irene; Weitkamp, B.; Jones, Ken; Aittomäki, Juha; Myles, Paul S.

doi:10.1046/j.1365-2044.2002.02606.x

Cited by 12 publications

(17 citation statements)

References 11 publications

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“…3 Biro's equation is simple, but does not correlate well with data obtained from patients and laboratory simulations. 10,12 We think that Foldes-Biro equation is an over-simplified description of a circle breathing system. The Foldes' equation might be explained as all the _ V FG would be utilized by the patient and the concentration of this utilized gas would determine the final F I O 2 .…”

Section: Discussionmentioning

confidence: 98%

The Relation Between Oxygen Consumption and the Equilibrated Inspired Oxygen Fraction in an Anesthetic Circle Breathing System: A Mathematic Formulation & Laboratory Simulations

Chen

Hsin

et al. 2008

Ann Biomed Eng

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Measuring a patients' oxygen consumption (VO2) is valuable in critical care and during anesthesia. Up to now, there has been no satisfactory equation describing the relation between the VO2, the fresh gas, and F(I)O(2) in a semi-closed circle breathing system. By adopting a "volume-weighted average concentration" approach and stepwise calculations, we have proposed an equation. We constructed a model with known simulated O(2) consumption ((SIM)VO2) to test our equation and two other previous methods (Biro's and Azami's). After 32 different laboratory scenarios, the %-error of the calculated VO2 ((CAL)VO2) from our method is -4.0 +/- 2.9%, which is significantly better than those from Azami's method (-8.8 +/- 6.2%, p < 0.01) and from Biro's method (-27.4 +/- 5.1%, p < 0.01). We also produce a Bland-Altman analysis of our (CAL)VO2 and (SIM)VO2. The 95% limits of agreement are -18.6-3.3 mL/min with a mean bias of -7.7 mL/min, which shows a good agreement. Our equation also explains the difference between F(I)O(2) and the oxygen concentration of the fresh gas in a semi-closed circle breathing system.

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Section: Discussionmentioning

confidence: 98%

The Relation Between Oxygen Consumption and the Equilibrated Inspired Oxygen Fraction in an Anesthetic Circle Breathing System: A Mathematic Formulation & Laboratory Simulations

Chen

Hsin

et al. 2008

Ann Biomed Eng

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“…Leonard et al . compared measurements using the Foldes‐Biro equation with those obtained by the reverse Fick method, using bolus thermodilution to measure pulmonary blood flow [3]. They found a mean overall bias of −73 ml.min −1 in their patients.…”

Section: Discussionmentioning

confidence: 99%

“…A total fresh gas flow of 1.3 l.min −1 was used, similar to that used by Leonard et al . [3]. This consisted of 1 l.min −1 air and 0.3 l.min −1 O 2 .…”

Section: Methodsmentioning

confidence: 99%

“…Leonard et al . compared the calculated using the Biro equation at low flows with the systemic calculated using the reverse Fick method in patients undergoing cardiac surgery [3]. They found the Biro method significantly underestimated the given by the reverse Fick method, which was surprising given that the reverse Fick method does not take into account oxygen uptake by the lung tissue.…”

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confidence: 99%

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Accuracy of the Foldes‐Biro equation for measurement of oxygen uptake during anaesthesia: a laboratory simulation

Stuart-Andrews¹,

Peyton

Robinson

et al. 2004

Anaesthesia

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Laboratory benchtop testing was conducted of the Biro method for measurement of oxygen uptake from an anaesthetic breathing system by patients during low flow anaesthesia. A high precision flow and gas concentration measurement system was employed in conjunction with a physical gas exchange simulation model to test the theoretical basis of the method under controlled conditions. Simulated oxygen uptake values between 200 and 350 ml x min(-1) were modelled. The Biro-derived measurement of simulated O(2) uptake significantly underestimated the target value (mean difference -88.5 ml x min(-1), or -31.7%). The bias was directly proportional to the simulated O(2) uptake. The Biro method has a systematic bias that cannot be explained by random measurement imprecision.

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“…Despite long experience in the use of single and combined-formula electrolyte solutions, constant progress in this area continues. New ionic formulas are being developed and are in some cases specific for particular situations and diagnoses (1,2).…”

Section: Introductionmentioning

confidence: 99%

The Energetic and Metabolic Effect of Ringerfundin (B. Braun) Infusion and Comparison with Plasma-Lyte (Baxter) in Healthy Volunteers

Zadák

Hyšpler

Hronek

et al. 2010

Acta Med. (Hradec Kralove, Czech Repub.)

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Electrolyte solutions are widely used in a number of clinical therapies in almost all areas of medicine, with particular importance in intensive care, surgery and the treatment of infections. Despite long experience in the use of single and combined-formula electrolyte solutions, constant progress in this area continues. New ionic formulas are being developed and are in some cases specific for particular situations and diagnoses (1, 2).Results from recent studies into the use of electrolyte solutions have shown the benefits of a class of solutions which in addition to appropriate proportions of sodium, potassium, magnesium and calcium also contain organic anions such as acetate, malate and occasionally lactate (6,7,10). The benefit of such infusion solutions is their ability to compensate fluctuations in the internal environment. This includes "buffering" the physiological acid-base status and ion fluctuations, which can significantly affect physiological functions, such as the potassium/ calcium ratio, maintenance of the extracellular volume by sodium content and control of variations in osmolality. Among the most commonly used solutions of this type are the formulations given in Tab. 1.It is possible that the presence of metabolisable organic anions (e.g. acetate, malate, lactate) could affect oxygen consumption, particularly where the patient receives large volumes of electrolyte solutions during volume resuscitation. This could result in changes in metabolic indicators such as VO 2 , VCO 2 , resting energy expenditure (REE), etc.The influence of electrolyte infusion solutions on the intracellular energy state is a largely underestimated parameter, despite the fact that active (endergonic) transport of the majority of ions across the cell membrane is dependent on it (11).In order to improve this therapeutic approach as much as possible and to obtain reliable clinical data which will allow further development and improvement of infusion solutions, a clinical study has been conducted to investigate the metabolic and energy response to Ringerfundin (B Braun Melsungen AG, Melsungen, Germany) and Plasma-Lyte (Baxter International Inc., Deerfield, USA) in healthy volunteers. Summary: Measurement of parameters of energy requirement, respiratory quotient (RQ), rate of oxygen consumption (VO 2 ) and rate of carbon dioxide production (VCO 2 ) reveal Ringerfundin as an excellent and metabolically stable-acting balanced ionic solution, which does not increase the consumption of O 2 or the total energy requirement. In conclusion, Ringerfundin was very well tolerated and in no case were observed undesirable effects.

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Measurement of systemic oxygen uptake during low‐flow anaesthesia with a standard technique vs. a novel method

Cited by 12 publications

References 11 publications

The Relation Between Oxygen Consumption and the Equilibrated Inspired Oxygen Fraction in an Anesthetic Circle Breathing System: A Mathematic Formulation & Laboratory Simulations

The Relation Between Oxygen Consumption and the Equilibrated Inspired Oxygen Fraction in an Anesthetic Circle Breathing System: A Mathematic Formulation & Laboratory Simulations

Accuracy of the Foldes‐Biro equation for measurement of oxygen uptake during anaesthesia: a laboratory simulation

The Energetic and Metabolic Effect of Ringerfundin (B. Braun) Infusion and Comparison with Plasma-Lyte (Baxter) in Healthy Volunteers

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