Korean J Anesthesiol.  2006 May;50(5):495-500. 10.4097/kjae.2006.50.5.495.

Effect of Fresh Gas Flow on the Work of Breathing of Closed Circuit Anesthesia Using Semiclosed Circuit System

• You HS
• Seo YS
• Shin HW
• Lee HW
• Lim HJ
• Chang SH
• Yoon SM

• KMID: 2092080
• DOI: http://doi.org/10.4097/kjae.2006.50.5.495

Abstract

BACKGOUND: The effect of anesthetic techniques, such as closed circuit anesthesia (CCA) using semiclosed circuit system and semiclosed circuit anesthesia (SCCA), on the work of breathing has not been studied yet in detail. This study was purposed to compare the work of breathing according to anesthetic technique (CCA, SCCA).
METHODS
Thirty patients were assigned to receive either SCCA group or CCA group (n = 15). Anesthesia was induced with propofol 2 mg/kg with 2% lidocaine 1 ml. Two percents isoflurane with O2 and N2O 2 L/min were given for 10 min to patients initially to wash in functional residual capacity and the breathing circuits. In SCCA group, anesthesia was maintained with 2% isoflurane in O2 2 L/min and N2O 2 L/min throughout the surgery. In CCA group, O2 was reduced to 200 ml/min and N2O to 100 ml/min with isoflurane vaporizer setting adjusted to 4% for anesthesia maintenance. When the operation was ended, the vaporizer setting of isoflurane deceased to zero and then O2 was increased to 4 L/min for the arousal of the patient. We measured the inspiratory/expiratory concentration of isoflurane, end-tidal CO2, the hemodynamic parameters, the change of airway pressure, the work of breathing, and compliance at anesthetic induction and emergence in both groups.
RESULTS
There were no significant differences in the inspiratory/expiratory concentrations of isoflurane, the hemodynamic parameters, end-tidal CO2, airway pressure, the work of breathing and compliance between the groups.
CONCLUSIONS
CCA using semiclosed circuit system does not increase the work of breathing compared to SCCA.

Keyword

closed circuit anesthesia; isoflurane; semi-closed circuit anesthesia; work of breathing

MeSH Terms

Anesthesia
Anesthesia, Closed-Circuit*
Arousal
Compliance
Functional Residual Capacity
Hemodynamics
Humans
Isoflurane
Lidocaine
Nebulizers and Vaporizers
Propofol
Respiration
Work of Breathing*
Isoflurane
Lidocaine
Propofol