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Predictable PaCO2 with two different flow settings using the Mapleson D system
1Department of Anaesthesia and Intensive Care, Ostersund Hospital, Sweden.
Acta Anaesthesiologica Scandinavica
|April 1, 1990
Summary
This study found two fresh gas flow settings for the Mapleson D breathing system are effective for maintaining normocapnia (normal carbon dioxide levels) or mild hypocapnia (low carbon dioxide levels) in adult patients during surgery.
Area of Science:
- Anesthesiology
- Respiratory Physiology
Background:
- The Mapleson D coaxial breathing system (Bain circuit) is commonly used in anesthesia.
- Optimizing fresh gas flow (VFG) and minute ventilation (VE) is crucial for managing ventilation and gas exchange.
Purpose of the Study:
- To evaluate two distinct VFG and VE settings with the coaxial Mapleson D system.
- To determine the suitability of these settings for achieving normocapnia and mild hypocapnia in adult surgical patients.
Main Methods:
- 59 adult patients (ASA I-III) undergoing various surgical procedures with controlled ventilation were studied.
- Two settings were tested: Alternative A (VFG 75 ml.min-1.kg-1, VE 150 ml.min-1.kg-1) and Alternative B (VFG 110 ml.min-1.kg-1, VE 175 ml.min-1.kg-1).
- Partial pressure of arterial carbon dioxide (PaCO2) was measured to assess ventilation.
Main Results:
- Alternative A resulted in a mean PaCO2 of 5.5 +/- 0.5 kPa, with 92% of patients in the 4.7-6.1 kPa range (normocapnia).
- Alternative B yielded a mean PaCO2 of 4.4 +/- 0.5 kPa, with 82% of patients in the 3.5-4.9 kPa range (mild hypocapnia).
Conclusions:
- Both tested VFG and VE settings are clinically suitable for the coaxial Mapleson D system.
- These settings effectively achieve desired levels of normocapnia or mild hypocapnia in adult surgical patients.