Before each analysis a standard curve consisting of eight points, including a zero-calibrator, was prepared and injected. Despite the higher canister temperature with lithium hydroxide, no noticeable amount of compound A was formed in our study, as was also found in the study of Förster et al. 4reported that KOH versus NaOH versus Ca(OH)2(calcium hydroxide) have inconsistent effects on compound A production. Anesthesiology 1999; 91: 1342–8, Versichelen L, Struys M, Rolly G, Bouche MP, Van Bocxlaer J: KOH-free CO. Versichelen LFM, Rolly G, Bouche MPLA, Van Bocxlaer JFP, Struys MMRF, Van Der Herten C, De Leenheer AP, Mortier EP: Bouche MPL, Van Bocxlaer JF, Rolly G, Versichelen LF, Struys MMRF, Mortier E, De Leenheer AP: Quantative determination of vapor phase compound A in sevoflurane based anesthesia systems. Spearman correlation coefficients were calculated between canister T°in, canister T°out, and compound Ainsp. Carbon dioxide forms a weak acid when it dissolves in water, carbonic acid: CO2 + H2O -> H2CO3. This is one of them. 2–4In the soda limes of the various manufacturing companies, sodium hydroxide (NaOH) and potassium hydroxide (KOH) are mostly used as initiators in the carbon dioxide chemical binding process. When CO2 is bubbled in a concentrated solution of KOH is gets absorbed forming KHCO3 ie the soapy bicarbonate of potassium. What is the birthday of carmelita divinagracia? Search for other works by this author on: Mazze RI, Jamison RL: Low-flow (1 l/min) sevoflurane: Is it safe? All Rights Reserved. An average correlation coefficient of 0.996 (n = 10) was obtained for the relation between the peak area ratio (ratio of compound A to internal standard) and the calibration concentrations. Provided that 100% O2was used in the setup, patient oxygen consumption was simulated. Our results with the KOH-free but NaOH-containing limes are in conflict with those of a recent report, 12in which less compound A was generated with the KOH-free (0.003% KOH) sodalimes Drägersorb 800 plus and Medisorb (Datex-Ohmeda, Bromma, Sweden), than with the classic Drägersorb 800. 12However, Medisorb contained only 1% NaOH, and Drägersorb 800 plus, 2% NaOH (such as was contained in Drägersorb 800 also), whereas in the KOH-free Sodasorb we studied, there was 3.75% NaOH. A significant correlation (P < 0.05) was found between the compound Ainspvalues and canister T°inin the Sofnolime (r = 0.35), KOH-free Sodasorb (r = 0.50), and Sodasorb (r = 0.32) groups. Although for all the other absorbents the temperature gradient was reversed and became pronounced in the second time period, it took much longer for the gradient with lithium hydroxide to reverse to somewhat lower values. A flow rate of approximately 160 ml/min was used. Insufficient data exist on the production of compound A during closed-system sevoflurane administration with newer carbon dioxide absorbents. Who of the proclaimers was married to a little person? The total median (with range) amounts (in millimeters) of liquid sevoflurane injected into the circuit during the 240-min examination period were 7.3 (6.9–7.9) (Sodasorb), 7.4 (6.6–9.4) (Sofnolime), 7.3 (6.7–8.7) (KOH-free Sodasorb), 6.2* (4.1–7.0) (Amsorb) and 7.4 (6.9–7.0) (lithium hydroxide) (*P < 0.01 vs. the other four groups). Anesth Analg 2000; 90: 1428–35, Murray JM, Renfrew CW, Bedi A, McCrystal CB, Jones DS, Fee JPH: Amsorb: A new carbon dioxide absorbent for use in anesthetic breathing systems. Median (−), mean (•), and minimum and maximum values of canister inflow and canister outflow (T°inand T°out[°C]) in the different groups (*P < 0.05 vs. the previous value in time). Fig. A significant correlation (P < 0.05) was found between compound Ainspvalues and canister T°outin the Sofnolime (r = 0.49) group only. This suggestion is evidenced in figure 3, in which the canister T°in–T°outdifference is shown: In the first time period, the temperature difference was larger for lithium hydroxide than for all the other absorbents (for simplicity, only Sodasorb is depicted in figure 3). With KOH-free (but sodium hydroxide [NaOH]-containing) soda limes even higher compound A concentrations are recorded than with standard Sodasorb. To measure compound Ainsp concentration in the inspired gas of the breathing circuit, 2-ml gas samples were taken and analyzed by capillary gas chromatography plus mass spectrometry. Copyright © 2020 Multiply Media, LLC. Our most striking results are that two carbon dioxide absorbents, Amsorb and lithium hydroxide, are devoid of compound A production, whereas the three other absorbents produce compound A in varying concentrations. At baseline and at regular intervals thereafter, end-tidal carbon dioxide partial pressure, end-tidal sevoflurane concentration, and canister inflow (T degrees(in)) and canister outflow (T degrees(out)) temperatures were measured. 1However, different carbon dioxide absorbents vary enormously in their capacity to produce compound A. The canister temperatures were almost the same for all absorbents examined, with T°outhigher than T°in; the only exception was with lithium hydroxide, which generated much higher temperatures (P < 0.05), with T°induring the first 120 min higher than T°out. 3. 1. 15Our in vitro assessment clearly shows that Amsorb is devoid of significant compound A generation and is the answer for the clinical practice, as has already been reported. Received from the Department of Anesthesia, Ghent University Hospital, Gent, Belgium. Anesthesiology 1998; 89: 929–41, Munday IT, Ward PM, Foden ND, Jones RM, Van Pelt FNAM, Kenna JC: Sevoflurane degradation by soda lime in a circle breathing system. In experimental conditions the formation of compound A was reportedly less with KOH-free soda limes, 3which were then produced by various companies, and alternate NaOH-free and KOH-free carbon dioxide absorbents became available. At an identical carbon dioxide charge, a particular aspect is shown with lithium hydroxide with its continuous increase of temperature, which is significantly higher (P < 0.05) than with the other carbon dioxide absorbents, but with T°inmoderately higher than T°out, suggesting not only an intense, but also a fast, binding of carbon dioxide. The Y piece of a modified PhysioFlex (Dräger) computer-controlled, closed-system anesthetic machine was connected to the artificial lung. Who is the longest reigning WWE Champion of all time? But ordinary solutions hardly absorb any CO2 at 1 atm. The ion at m/z 128 was selected as the target ion for quantitative purposes. The peak value for canister T°inwas between 15 and 60 min, whereas that for T°outwas later, as shown in figure 2. Various fresh carbon dioxide absorbents were used: Sodasorb (n = 6), Sofnolime (n = 6), and potassium hydroxide (KOH)-free Sodasorb (n = 7), Amsorb (n = 7), and lithium hydroxide (n = 7). The syringes were connected to the breathing circuit using three-way valves and Luer-lock connections, one in the inspiratory limb (for compound Ainspmeasurement) and one in the expiratory limb (for compound Aexpmeasurement) of the breathing circuit. 2. This gas was brought to a stand-alone Ultima gas analyzer (Datex, Helsinki, Finland) for measuring all respiratory gases. However, they are highly reactive compounds, which cause the breakdown of sevoflurane in the canister in the breathing circuit. Table 1. By making a further technical change, this was no longer necessary during the preparation period in the other four groups. In contrast, Cunningham et al. Anesthesiology 1999; 91: 1192–93, This site uses cookies. Calibration curves were linear over a range of 0.3–75 parts per million (ppm; vol/vol). Whether compound A has an effect clinically on renal function has been debated, but some authors question the use of sevoflurane in low-flow conditions. By computer control the “consumed” oxygen or volume loss is replaced by an identical (volume/volume [vol/vol]) inflow of oxygen, visualized on the PhysioFlex machine as oxygen consumption. The result is potassium bicarbonate and water. A modified PhysioFlex apparatus (Dräger, Lübeck, Germany) was connected to an artificial test lung (inflow at the top of the bellow approximately/= 160 ml/min CO2; outflow at the Y piece of the lung model approximately/= 200 ml/min, simulating oxygen consumption). Why don't libraries smell like bookstores? Why does KOH (potassium hydroxide) absorb CO2. The median (range, minimum and maximum) values for lithium hydroxide and Sodasorb are shown. 1However, different carbon dioxide absorbents vary enormously in their capacity to produce compound A. In the Amsorb-containing or lithium hydroxide–containing systems, compound Ainspwas present in concentrations almost equal (maximum median value for Amsorb was 1.3 ppm and for lithium hydroxide was 1.6 ppm) to those contained intrinsically in commercial sevoflurane (1.06 ± 0.28 ppm). The outlet gases of the gas analyzer were scavenged. The values for compound Ainspwith Sofnolime were higher (P < 0.01) than with all the other groups, and those with KOH-free Sodasorb higher (P < 0.01) than with the remaining groups, whereas the Sodasorb results were higher (P < 0.01) than those for Amsorb and lithium hydroxide.