| JOURNAL HOME | CME HOME | THIS MONTH | PAST ISSUES | ETOC | COLLECTIONS |
| AUTHORS | REVIEWERS | EDITORIAL BOARD | FEEDBACK | RSS | HELP |
 
|
|
|
||
|
|
© 1999 International Anesthesia Research Society
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
Abstract |
|---|
 Top Abstract IntroductionMethodsResultsDiscussionReferences |
|---|
Normal (hydrated) soda lime absorbent (approximately 95% calcium hydroxide [Ca(OH)2], the remaining 5% consisting of a mixture of sodium hydroxide [NaOH] and potassium hydroxide [KOH]) degrades sevoflurane to the nephrotoxin Compound A, and desiccated soda lime degrades desflurane, enflurane, and isoflurane to carbon monoxide (CO). We examined whether the bases in soda lime differed in their capacities to contribute to the production of these toxic substances by degradation of the inhaled anesthetics. Our results indicate that NaOH and KOH are the primary determinants of degradation of desflurane to CO and modestly augment production of Compound A from sevoflurane. Elimination of these bases decreases CO production 10-fold and decreases average inspired Compound A by up to 41%. These salutary effects can be achieved with only slight decreases in the capacity of the remaining Ca(OH)2 to absorb carbon dioxide.
Implications: The soda lime bases used to absorb carbon dioxide from anesthetic circuits can degrade inhaled anesthetics to compounds such as carbon monoxide and the nephrotoxin, Compound A. Elimination of the bases sodium hydroxide and potassium hydroxide decreases production of these noxious compounds without materially decreasing the capacity of the remaining base, Ca(OH)2, to absorb carbon dioxide.
|
Introduction |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Carbon dioxide absorbents (i.e., soda lime and Baralyme® brand absorbent [Allied Healthcare Products, St. Louis, MO]) can degrade the inhaled anesthetics enflurane1, isoflurane2, and desflurane (1) to carbon monoxide (CO). Degradation only occurs when the normal water content (13%–15%) is markedly decreased (2). For example, approximately 90% of the water must be removed from soda lime before appreciable amounts of CO are produced. For a given minimum alveolar anesthetic concentration (MAC) multiple, more CO results from degradation of desflurane than from degradation of isoflurane.
Degradation of inhaled anesthetics by Baralyme® produces more CO at a given water content than does degradation by soda lime (2). The bases in soda lime absorbent consist of approximately 95% calcium hydroxide (Ca[OH]2), the remaining 5% consists of a mixture of sodium hydroxide (NaOH) and potassium hydroxide (KOH). The bases in Baralyme® consist of approximately 82% Ca(OH)2, with the balance consisting of 12% barium hydroxide [Ba(OH)2] and 6% KOH. Thus, both absorbents primarily rely on Ca(OH)2 to remove carbon dioxide but include other bases (NaOH, KOH, and Ba[OH]2) to assist in this process. The difference in the capacity of Baralyme® and soda lime to degrade inhaled anesthetics to CO suggests that these bases, particularly KOH, may be primary determinants of the production of CO. Other investigations also suggest the importance of KOH with a lesser role for NaOH (3–6).
Although carbon dioxide absorbents do not degrade sevoflurane or halothane to CO, they do degrade these anesthetics to unsaturated compounds (respectively, Compound A [CH2F-O-C(=CF2)(CF3)] and CF2=CBrCl) (7–9). Degradation to Compound A or CF2=CBrCl does not require dehydration of the absorbents. Dehydration of soda lime or Baralyme® increases the destruction of sevoflurane (4,5) but may either increase (Baralyme®) or decrease (soda lime) the production of Compound A (10). As with the degradation of inhaled anesthetics to CO, Baralyme® is thought to produce more Compound A from sevoflurane than does soda lime (11), again suggesting the importance of particular bases to the degradation.
Both CO and Compound A are toxic. The toxicity of CO is well known. The anesthetic relevance of this toxicity is suggested by the finding by Frink et al. (12) that the degradation of desflurane can produce dangerous concentrations of CO in pigs. The nephrotoxicity of Compound A is indicated by the results of studies in rats (8,13–16), monkeys (17), and humans (18–21). Thus, it seems useful to pursue measures that might decrease production of CO or Compound A.
We examined the relative contributions of the desiccated components of soda lime (NaOH, KOH, or Ca[OH]2) to the production of CO from desflurane. We hypothesized that the production of CO depended primarily on the presence of the stronger bases KOH and NaOH. We further hypothesized that Ca(OH)2 would normally absorb carbon dioxide in the absence of NaOH and/or KOH. Finally, we hypothesized that hydrated soda lime without KOH or NaOH would produce less Compound A from sevoflurane.
|
Methods |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Dr. David Chin (Senior Research Chemist, WR Grace & Co., Lexington, MA) provided eight samples of soda lime absorbent: normal soda lime (1.5 g% or 1.41% of base as NaOH, 3.0 g% or 2.0% of base as KOH, balance Ca[OH]2); lime (for simplicity, we define "lime" as a generic term for all absorbents containing Ca[OH]2 with or without other bases) with 1.1 g% or 1.02% of base as NaOH, 2.2% or 2.04% of base as NaOH, and 4.2% or 3.90% of base as NaOH, respectively (balance Ca[OH]2; no KOH); lime with 1.5% or 1.00% of base as KOH, 3.0% or 2.00% of base as KOH, and 5.8% or 3.91% of base as KOH, respectively (balance Ca[OH]2; no NaOH); and Ca(OH)2, alone. Dr. Chin supplied these limes in two forms. One contained a normal water compliment (i.e., 14.5%–17.2% water). The other nominally contained no water. In fact, we found that the nominally dried limes contained a small and variable amount of water. For studies of desiccated limes, the water content from the normally hydrated limes was removed by placing the limes in vessels through which we directed a flow of nitrogen. The vessels were weighed and placed in an oven at approximately 80°C. The outflow from the vessel was attached to a vacuum. This drying process continued until the vessel did not change in weight with further drying. All eight variants were tested as completely dry limes and as limes containing 14.5%–17.2% water (i.e., a total of 16 variants). Water content for specific limes was determined by drying 10 g of material in an oven at 125°C for 60 min and taking the difference in weight as indicative of the water content.
Baxter Pharmaceutical Products (Liberty Corner, NJ) donated desflurane. Sevoflurane was purchased from Abbott Laboratories (Abbott Park, IL). Constant concentrations of 4.52% desflurane and 2.17% sevoflurane were prepared in helium in H cylinders. Desflurane concentration was analyzed by using gas chromatography referenced to volumetric primary standards. Cylinder gas served as a secondary standard as well as a source of anesthetic.
We sealed the open ends of barrels of 30-mL syringes with rubber stoppers, each pierced with a needle. Gases were directed through the needle. We placed an amount of absorbent in each barrel approximately equaling the active components of 25 g of standard absorbent (e.g., for dry absorbent, we placed 21 g in each barrel). The luer-lock at the exit from the syringe barrel was connected to Teflon® (DuPont, Wilmington, DE) tubing terminating in a three-way stopcock that allowed sampling of exiting gas. Barrels were immersed in a constant-temperature waterbath at 45°C. The rubber stopper also was pierced with a temperature probe (Yellow Springs Instrument Co., Inc., Yellow Springs, OH), with the probe tip placed mid-absorbent.
Desflurane-containing gas flowed through each syringe at 12.5 mL/min. Flow rates were calibrated using a bubble flowmeter. Entering and exiting concentrations of desflurane and exiting concentrations of CO were measured by using gas chromatography (see below). At 5, 10, 15, 30, 60, 120, 180, and 240 min, we sampled and analyzed gases from the inflow and outflow of all syringes. All studies were performed in quadruplicate (four absorbent systems).
Identical conditions were used to test the degradation of sevoflurane to Compound A, except for substitution of 2.17% sevoflurane for desflurane, and except that only two hydrated limes were studied. The first of these was normal soda lime containing 1.5% NaOH and 3% KOH, balance Ca(OH)2. The second contained only Ca(OH)2. We did not measure the capacity of limes to degrade sevoflurane to CO because previous results indicate that such degradation does not occur (2).
For CO analysis, we used a thermal conductivity detector gas chromatograph equipped with a 5.8-m, 0.22-mm internal diameter column containing a washed molecular sieve, 5 A (Alltech, Deerfield, IL) maintained at 152°C, with a helium carrier flow. Sensitivity permitted detection of 10 ppm CO. Calibration standards (99.9% purity) contained 1000 ppm CO obtained from Altair Gas and Equipment, Inc. (South San Francisco, CA). We demonstrated linearity of the gas chromatographic response over the entire range of concentrations studied (up to 60,000 ppm).
For anesthetic analyses, we used a flame-ionization detector gas chromatograph equipped with a 4.6-m, 0.22-mm internal diameter column containing 10% SF96 on Chromosorb WHP (Altech Associates, Deerfield, IL) maintained at 86°C, using a carrier flow of nitrogen. Linearity was obtained over the concentration ranges studied.
The capacity of lime containing only Ca(OH)2 to absorb carbon dioxide was compared with that of regular soda lime using a standard anesthetic machine and circuit. The lower of two absorbent canisters was filled with 1000 g of fresh soda lime (1.5% NaOH, 3% KOH, and Ca[OH]2) or with 1000 g of pure Ca(OH)2, containing 15% and 17% moisture, respectively. The upper canister was left empty. The circuit was assembled as in clinical practice, with the ventilator attached to the rebreathing bag port. A 3-L rebreathing bag connected to the patient Y-piece of the circuit acted as a compliant "lung." Oxygen at a flow rate of 0.5 L/min was delivered to the usual inflow port as the fresh gas inflow (i.e., this inflow rate approached that of a closed system). A flow rate of 300 mL/min carbon dioxide (flow calibrated with a bubble flowmeter) was directed into the lung. The lung was ventilated 10 times per minute, producing a minute ventilation of 5 L/min. The end-tidal concentration of CO2 was 42–46 mm Hg (measured by using a 5250 RGM analyzer [Ohmeda, Liberty Corner, NJ]). Each study continued until the inspired CO2 partial pressure reached 30 mm Hg.
Values are presented as the quadruplicate determinations or the average of the quadruplicate determinations made at each time point. Using the trapezoid rule, we determined the area under the curve for the CO concentrations produced over time. Linear regression analysis was applied to the correlations of production of CO. For statistical analysis, we used either a Welch t-test (correcting for unequal standard deviations) or an analysis of variance with Dunnett's post hoc test for multiple comparison.
|
Results |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
No moist absorbent produced significant concentrations of CO from desflurane, with peak CO values consistently <50 ppm. The fraction of desflurane leaving the absorber (i.e., the exiting divided by the entering concentration) approached 1.0, except during the first 5–10 min, when filling of the system and adsorption by the absorbent led to a lower fraction.
All desiccated absorbents completely eliminated the appearance of desflurane in the outflow for 10–60 min. The fraction of desflurane output at 60–240 min was approximately 0.9, except for 5.8% KOH, for which it was 0.5–0.7 at 120–240 min. Temperatures in all absorbents remained within 1°C of the target temperature of 45°C.
CO production by the dry absorbents depended on the composition of the lime. The highest peak values (mean ± SD) were found with dry standard soda lime (22,100 ± 400 ppm) and with limes containing KOH (for 1.5% KOH [1.00% of the base]: 10,900 ± 600 ppm; for 3.0% KOH [2.00% of the base]: 15,300 ± 1,200 ppm; for 5.8% KOH [3.91% of the base]: 21,900 ± 500 ppm) (Fig. 1). Percentages of base are calculated as (mEq of base in question)/(total mEq of base). The CO values for equal percentages of NaOH base were 16%–70% lower than those of KOH (for 1.1% NaOH [1.02% of base]: 2,910 ± 890 ppm; for 2.2% NaOH [2.04% of base]: 13,200 ± 2,100 ppm; for 4.2% NaOH [3.9% of base]: 10,500 ± 1,800 ppm). Lime containing only Ca(OH)2 gave a peak value of 718 ± 586 ppm, significantly lower than the values associated with the lowest concentrations of either NaOH or KOH (Welch t-test with the Bonferroni correction, P < 0.05 or P < 0.01, respectively) and lower than the value associated with the dry standard lime (P < 0.0001). The peak value for CO in the dry standard soda lime equaled that obtained with 5.8% KOH but significantly exceeded that for any other dry lime (analysis of variance with Dunnett's multiple comparison test, P < 0.01).
|
), NaOH (
), or the combination of these (standard lime; 
) in desiccated lime increases the peak CO attained from passage of 4.5% desflurane at 12.5 mL/min through 21 g of lime relative to the peak obtained from desiccated lime without KOH or NaOH (i.e., containing only Ca[OH]2; 
). The effects of KOH and NaOH seem to directly depend on the concentration of each. KOH is more potent than NaOH.The peak values were not sustained. CO output decreased radically with the passage of time. For example, at 240 min, the value for CO from desiccated standard soda lime was 5% of the value at 30 min; similarly, at 240 min, the value for the desiccated lime containing only Ca(OH)2 was 33% of the value at 30 min (Fig. 2). The results for the areas under the curve of CO production (i.e., the average CO production) over 60 min and over 240 min reflected those of the peak values for all dry limes (Figs. 3 and 4). Values for the lime containing 4.2% NaOH seem to be aberrant (outliers) and were not included in the regression analysis provided in Figures 3 and 4.
|
|
|
The period of time until 1000 g of fresh soda lime allowed the inspired CO2 to increase to 5 mm Hg during delivery of 300 mL/min CO2 into an anesthetic circuit was 8.54 ± 0.56 h. For the Ca(CO)2 absorbent (no other base), this period was 7.33 ± 0.63 h or 14% less (difference not significant). For a 30-mm Hg increase in inspired CO2, the values were 10.91 ± 0.36 h, 9.61 ± 0.34 h, and 12% (P < 0.02), respectively (Fig. 5).
|
Sevoflurane appeared in the outflow sooner in wet standard soda lime than in wet lime containing only Ca(OH)2. Within 60 min, the fraction exiting the absorber approached 1.0 in both components. Peak Compound A values arising from the standard lime slightly but significantly exceeded those from the pure Ca(OH)2 lime (21.6 ± 0.4 vs 20.3 ± 0.5 ppm; P < 0.05 [Welch t-test]). The differences increased for area under the curve measurements: over 60 min, the difference was 19.1 ± 0.2 vs 16.2 ± 1.2 ppm (P < 0.05); over 240 min, it was 20.8 ± 0.3 vs 12.3 ± 0.3 ppm (P < 0.0001) for standard lime versus pure Ca(OH)2 lime.
|
Discussion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Our data indicate that absorbent composition materially influences the concentration of CO that results from desflurane degradation by desiccated limes. Absorbent containing only Ca(OH)2 produces less CO than any other dry lime with mean peak values (Fig. 1) and mean area under the curve values over 60 and 240 min (Figs. 3 and 4) always <1000 ppm. The mean peak CO value and the area under the curve values for 60 and 240 min for desiccated standard lime (i.e., lime containing both KOH and NaOH, as well as Ca[OH]2) are at least 20 times greater than those for the desiccated lime without NaOH and KOH (i.e., containing only Ca[OH]2 as the active base). Although for all the tested limes, the average CO concentration for 60 min (Fig. 3) was greater than that for 240 min (Fig. 4), the relative effects of increasing concentrations of NaOH and KOH were unchanged.
Both NaOH and KOH increase the production of CO from the action of desiccated lime on desflurane, with KOH having a greater capacity than NaOH to produce CO (Figs. 1, 3, and 4). Except for one set of aberrant values, that for either 2.2% or 4.2% NaOH, the increase in capacity is a function of the fraction of these bases in each lime. One observation suggests that the values for 4.2% NaOH, rather than those for 2.2% NaOH, are outliers. The value for standard soda lime is consistent with a higher capacity of NaOH to degrade desflurane to CO than implied by the value for 4.2% NaOH. That is, presuming the correctness of the values for limes containing only KOH and Ca(OH)2 (Figs. 1, 3, and 4), the standard lime should not produce the peak or average CO values from the 3% KOH (2.00% of the base) unless the 1.5% NaOH (1.41% of the base) added appreciably to the CO formation. However, the values for 1.1% NaOH and 4.2% NaOH are consistent with proportional increases in CO (Figs. 1, 3, and 4).
The implications of our findings are the same regardless of which values are correct: (a) both NaOH and KOH in standard lime are responsible for most of the degradation of desflurane (and, presumably, enflurane and isoflurane) to CO; (b) in this regard, KOH is more potent than NaOH; and (c) NaOH and KOH are responsible for a substantial fraction of the Compound A produced by the action of limes on sevoflurane. These conclusions parallel those of Förster et al. (4,5), particularly as they involve sevoflurane's conversion to Compound A. We also conclude that limes without NaOH or KOH efficiently remove CO2 from the respired gases in an anesthetic circuit. In summary, these observations suggest that CO2 absorbents might be made safer (produce less CO and Compound A) if NaOH and KOH were excluded as components.
How might the results of this bench study apply to clinical practice? Because of the high affinity of CO for blood, nearly all inspired CO is taken up by blood. The 10-fold greater area under the curve for standard lime versus lime with only Ca(OH)2 implies that carboxyhemoglobin blood levels from desflurane degradation to CO will be 10-fold less with lime containing only Ca(OH)2. This reasoning suggests that conversion to limes containing only Ca(OH)2 would effectively remove any risk of CO poisoning from degradation of desflurane. Presumably such increased safety would also apply to enflurane and isoflurane, but this was not tested in the present study. Conversion to limes containing only Ca(OH)2 also would increase the safety of sevoflurane delivery by materially decreasing the concentration of Compound A.
We did not test degradation of sevoflurane to Compound A by dry limes because our previous work with dry soda lime demonstrated that a lower Compound A concentration resulted (10). In addition, Förster et al. (5) have shown that dry Ca(OH)2 or Ba(OH)2 does not appreciably degrade sevoflurane. Thus, it seemed that the important question was whether hydrated lime with versus without KOH and NaOH produced less Compound A.
The open (nonrecirculating) system we used for determination of CO and Compound A production provides a ratio of flow rate to absorbent (12.5 mL/25 g or 0.5 mL · min-1 · g-1) approximately 4 times less than that found in clinical practice (e.g., a minute ventilation of 5 L/min through 2–3 kg of absorbent). Using a higher flow might not have changed the peak CO concentration because the greater production of CO due to the higher desflurane supply would likely have been offset by the dilution resulting from the larger volume of background gas (helium). However, the reaction with NaOH and KOH in the present experiment might have been shortened because the greater supply of desflurane would exhaust the supply of NaOH and KOH faster. The temperature (45°C) and anesthetic concentrations (as MAC fractions) are clinically relevant. Forty-five degrees Celsius is approximately the absorbent temperature found at low flow rates (20,21). The exothermic reaction of desflurane with absorbent might have increased the temperature >45°C if no waterbath had been used (22). Such an effect would have been greatest in the experiments with the highest degradation of desflurane and thus would have increased the difference between the results for standard soda lime and pure Ca(OH)2.
We did not add CO2 to the delivered gases in our experiment. Such an addition might have had a mixed effect on CO production. Absorbent temperature might increase because of the exothermic reaction of CO2 and soda lime. The increased temperature would increase destruction of desflurane. At the same time, the reaction produces water and thus moistens the absorbent and might have slowed desflurane destruction, and the reaction of CO2 with absorbent components would have decreased the amount of available base. In any case, adding CO2 would have affected all absorbent reactions similarly in the production of CO and Compound A.
In summary, although permanent injury in humans has not been reported to have occurred from the degradation of anesthetics to CO or Compound A, the issue of such poisoning is of clinical concern. We provide evidence that this concern can be decreased by removing NaOH and KOH, particularly the latter, from conventional limes. Such removal would not materially influence the capacity of the residual Ca(OH)2 to absorb CO2.
|
Footnotes |
|---|
1 Moon R, Meyer A, Scott D, et al. Intraoperative carbon monoxide toxicity [abstract]. Anesthesiology 1990;73:1049.
2 Moon R, Ingram C, Brunner E, Meyer A. Spontaneous generation of carbon monoxide within anesthetic circuits [abstract]. Anesthesiology 1991;75:873.
|
References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
- Lentz R. CO poisoning during anesthesia poses puzzles. Foundation News 1994;9:13–4.
- Fang ZX, Eger EI II, Laster MJ, et al. Carbon monoxide production from degradation of desflurane, enflurane, isoflurane, halothane, and sevoflurane by soda lime and Baralyme®. Anesth Analg 1995;80:1187–93.[Abstract]
- Funk W, Gruber M, Wild K, Hobbhahn J. Dry soda lime markedly degrades sevoflurane during simulated inhalation induction. Br J Anaesth 1999;82:193–8.[Abstract]
- Förster H, Dudziak R. Über die Ursachen der Reaktion zwischen trockenem Atemkalk und halogenierten Inhalationsanästhetika. Anaesthesist 1997;46:1054–63.[Web of Science][Medline]
- Förster H, Warnken UH, Askali F. Unterschiedliche Reaktion von Sevofluran mit einzelnen Komponenten von Atemkalk. Anaesthesist 1997;46:1071–5.[Web of Science][Medline]
- Baxter PJ, Garton K, Kharasch ED. Mechanistic aspects of carbon monoxide formation from volatile anesthetics. Anesthesiology 1998;89:929–41.[Web of Science][Medline]
-
Wallin RF, Regan BM, Napoli MD, Stern IJ. Sevoflurane: a new inhalational anesthetic agent. Anesth Analg 1975;54:758–65.
[Abstract/Free Full Text] - Morio M, Fujii K, Satoh N, et al. Reaction of sevoflurane and its degradation products with soda lime: toxicity of the byproducts. Anesthesiology 1992;77:1155–64.[Web of Science][Medline]
-
Raventos J, Lemon PG. The impurities in Fluothane: their biological properties. Br J Anaesth 1965;37:716–37.
[Abstract/Free Full Text] - Eger EI II, Ionescu P, Laster MJ, Weiskopf RB. Baralyme® dehydration increases and soda lime dehydration decreases the concentration of Compound A resulting from sevoflurane degradation in a standard anesthetic circuit. Anesth Analg 1997;85:892–8.[Abstract]
- Bito H, Ikeda K. Long-duration, low-flow sevoflurane anesthesia using two carbon dioxide absorbents: quantitation of degradation products in the circuit. Anesthesiology 1994;81:340–5.[Web of Science][Medline]
- Frink EJ Jr, Nogami WM, Morgan SE, Salmon RC. High carboxyhemoglobin concentrations occur in swine during desflurane anesthesia in the presence of partially dried carbon dioxide absorbents. Anesthesiology 1997;87:308–16.[Web of Science][Medline]
- Gonsowski CT, Laster MJ, Eger EI II, et al. Toxicity of Compound A in rats: effect of a 3-hour administration. Anesthesiology 1994;80:556–65.[Web of Science][Medline]
- Gonsowski CT, Laster MJ, Eger EI II, et al. Toxicity of Compound A in rats: effect of increasing duration of administration. Anesthesiology 1994;80:566–73.[Web of Science][Medline]
- Keller KA, Callan C, Prokocimer P, et al. Inhalation toxicity study of a haloalkene degradant of sevoflurane, Compound A (PIFE), in Sprague-Dawley rats. Anesthesiology 1995;83:1220–32.[Web of Science][Medline]
- Kandel L, Laster MJ, Eger EI II, et al. Nephrotoxicity in rats undergoing a 1-hour exposure to Compound A. Anesth Analg 1995;81:559–63.[Abstract]
- Newton PE, Friedman MB, Hulsebos LH, et al. Acute inhalation toxicity of sevoflurane with 75 or 100 ppm Compound A [abstract]. Toxicologist 1998;42:254.
-
Goldberg ME, Cantillo J, Gratz I, et al. Dose of Compound A, not sevoflurane, determines changes in the biochemical markers of renal injury in healthy volunteers. Anesth Analg 1999;88:437–45.
[Abstract/Free Full Text] - Higuchi H, Sumita S, Wada H, et al. Effects of sevoflurane and isoflurane on renal function and on possible markers of nephrotoxicity. Anesthesiology 1998;89:307–22.[Web of Science][Medline]
- Eger EI II, Gong D, Koblin DD, et al. Dose-related biochemical markers of renal injury after sevoflurane versus desflurane anesthesia in volunteers. Anesth Analg 1997;85:1154–63.[Abstract]
- Eger EI II, Koblin DD, Bowland T, et al. Nephrotoxicity of sevoflurane versus desflurane anesthesia in volunteers. Analg 1997;84:160–8.[Abstract]
- Wissing H, Kuhn I, Dudziak R. Zur Temperaturentwicklung von Inhalationsanästhetika auf trockenem Atemkalk. Anaesthesist 1997;46:1064–70.[Web of Science][Medline]
This article has been cited by other articles:
|
|
 |
|
  M. J. Laster and E. I. Eger II Temperatures in Soda Lime During Degradation of Desflurane, Isoflurane, and Sevoflurane by Desiccated Soda Lime Anesth. Analg., September 1, 2005; 101(3): 753 - 757. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Laster, P. Roth, and E. I Eger II Fires from the Interaction of Anesthetics with Desiccated Absorbent Anesth. Analg., September 1, 2004; 99(3): 769 - 774. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Knolle, W. Linert, and H. Gilly The Color Change in CO2 Absorbents On Drying: An In Vitro Study Using Moisture Analysis Anesth. Analg., July 1, 2003; 97(1): 151 - 155. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M.-P. L. A. Bouche, L. F. M. Versichelen, M. M. R. F. Struys, J. F. P. Van Bocxlaer, A. P. De Leenheer, E. P. Mortier, and G. Rolly No Compound A Formation with Superia(R) During Minimal-Flow Sevoflurane Anesthesia: A Comparison with Sofnolime(R) Anesth. Analg., December 1, 2002; 95(6): 1680 - 1685. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Knolle, G. Heinze, and H. Gilly Small Carbon Monoxide Formation in Absorbents Does Not Correlate with Small Carbon Dioxide Absorption Anesth. Analg., September 1, 2002; 95(3): 650 - 655. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Knolle, G. Heinze, and H. Gilly Carbon Monoxide Formation in Dry Soda Lime is Prolonged at Low Gas Flow Anesth. Analg., August 1, 2001; 93(2): 488 - 493. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. I. Mazze and H. Higuchi Composition of CO2 Absorbents Anesth. Analg., May 1, 2001; 92(5): 1356 - 1357. [Full Text] [PDF]
|
|
|
|
 |
|
 L. Versichelen, M. P. Bouche, M. Struys, J. Van Bocxlaer, E. Mortier, A. P. de Leenheer, and G. Rolly Compound A production from sevoflurane is not less when KOH-free absorbent is used in a closed-circuit lung model system Br. J. Anaesth., March 1, 2001; 86(3): 345 - 348. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Higuchi, Y. Adachi, S. Arimura, M. Kanno, and T. Satoh Compound A Concentrations During Low-Flow Sevoflurane Anesthesia Correlate Directly with the Concentration of Monovalent Bases in Carbon Dioxide Absorbents Anesth. Analg., August 1, 2000; 91(2): 434 - 439. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Knolle and H. Gilly Absorption of Carbon Dioxide by Dry Soda Lime Decreases Carbon Monoxide Formation from Isoflurane Degradation Anesth. Analg., August 1, 2000; 91(2): 446 - 451. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Yamakage, S. Yamada, X. Chen, S. Iwasaki, N. Tsujiguchi, and A. Namiki Carbon Dioxide Absorbents Containing Potassium Hydroxide Produce Much Larger Concentrations of Compound A from Sevoflurane in Clinical Practice Anesth. Analg., July 1, 2000; 91(1): 220 - 224. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. R. Stabernack, R. Brown, M. J. Laster, R. Dudziak, and E. I Eger II Absorbents Differ Enormously in Their Capacity to Produce Compound A and Carbon Monoxide Anesth. Analg., June 1, 2000; 90(6): 1428 - 1435. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. F. Bedford and H. E. Ives The Renal Safety of Sevoflurane Anesth. Analg., March 1, 2000; 90(3): 505 - 508. [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
