title: Compound A, formaldehyde and methanol concentrations during low-flow sevoflurane anaesthesia: comparison of three carbon dioxide absorbers.
abstract: OBJECTIVE
  To determine compound A, formaldehyde and methanol concentrations in low-flow anaesthesia using different carbon dioxide absorbers.
  
  
  METHODS
  Fifteen patients scheduled for general or urological surgery were exposed to low-flow (500 ml/min) anaesthesia with sevoflurane. The patients were randomly allocated to three groups: soda lime, DrägerSorb Free or Amsorb Plus. The concentrations of compound A, formaldehyde and methanol were sampled and analysed from the limbs of the anaesthesia circuit at T30 (30 min after the start of low-flow sevoflurane anaesthesia), T90 (90 min) and T150 (150 min). The temperatures of the absorbers were measured at the same time.
  
  
  RESULTS
  Statistically significant differences (P < 0.05) were found in the production of compound A from soda lime (with the highest values), DrägerSorb Free and Amsorb Plus at each measurement time. Only traces of methanol (ranging from < 0.131 to 3.799 mg/m(3)) were measured, higher with Amsorb Plus (statistically significant differences were found only at T90). The formaldehyde values (ranging from < 0.1227 to 17.79 mcg/m(3) p.p.b.) were higher with soda lime, and the difference was statistically significant at T150 and, in the inspiratory limb only, at T90. The temperatures of the absorbers were higher for soda lime and lower for Amsorb Plus; the difference was statistically significant at T0 in the upper canister and at T30 in both canisters.
  
  
  CONCLUSIONS
  The concentrations of harmful products in the circuit were negligible and were lower using the new-generation absorbers. Using Amsorb Plus, the temperatures in the canisters were lower than with the other two absorbers.
authors: Department of Anaesthesia and Intensive Care, Nuovo Ospedale San Giovanni di Dio, Via Mannelli no. 87, 50136 Florence, Italy. federica.marini@tin.it
authors: F
authors: F
authors: Marini
authors: I
authors: I
authors: Bellugi
authors: D
authors: D
authors: Gambi
authors: M
authors: M
authors: Pacenti
authors: S
authors: S
authors: Dugheri
authors: L
authors: L
authors: Focardi
authors: G
authors: G
authors: Tulli
mesh_terms: D000327:Adsorption; D000368:Aged; D000769:Anesthesia, Inhalation / Q000295:instrumentation* / Q000379:methods; D018685:Anesthetics, Inhalation; D002122:Calcium Chloride; D017610:Calcium Compounds; D002126:Calcium Hydroxide; D002245:Carbon Dioxide / Q000737:chemistry; D004869:Equipment Safety; D004987:Ethers / Q000032:analysis; D005557:Formaldehyde / Q000032:analysis; D006801:Humans; D006845:Hydrocarbons, Fluorinated / Q000032:analysis; D000432:Methanol / Q000032:analysis; D008738:Methyl Ethers; D008875:Middle Aged; D010087:Oxides; D000077149:Sevoflurane; D012972:Sodium Hydroxide; D013997:Time Factors
chemical_list: C400293:Amsorb; D018685:Anesthetics, Inhalation; D017610:Calcium Compounds; D004987:Ethers; D006845:Hydrocarbons, Fluorinated; D008738:Methyl Ethers; D010087:Oxides; D002245:Carbon Dioxide; D005557:Formaldehyde; D000077149:Sevoflurane; C004569:soda lime; D012972:Sodium Hydroxide; C078742:fluoromethyl 2,2-difluoro-1-(trifluoromethyl)vinyl ether; D002122:Calcium Chloride; D002126:Calcium Hydroxide; D000432:Methanol