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Biologically variable ventilation improves oxygenation and respiratory mechanics during one-lung ventilation
Michael C McMullen1, Linda G Girling, M Ruth Graham
1Anesthesia Research Laboratory, Winnipeg, Manitoba, Canada.
Anesthesiology
|July 1, 2006
Summary
Biologically variable ventilation (BVV) improved oxygenation and lung mechanics during one-lung ventilation (OLV) compared to conventional monotonous control mode ventilation (CMV). BVV enhanced gas exchange and static compliance, even after returning to two-lung ventilation.
Area of Science:
- Anesthesiology
- Critical Care Medicine
- Respiratory Physiology
Background:
- Hypoxemia and atelectasis are common complications during one-lung ventilation (OLV).
- Biologically variable ventilation (BVV) utilizes microprocessor-controlled variations in respiratory rate and tidal volume.
- Previous studies suggest BVV may improve oxygenation during lung reinflation post-OLV.
Purpose of the Study:
- To compare the efficacy of BVV versus conventional monotonous control mode ventilation (CMV) during OLV.
- To assess the impact of BVV on gas exchange and respiratory mechanics in a porcine model.
- To evaluate the persistence of BVV's benefits upon return to two-lung ventilation.
Main Methods:
- Eight pigs were studied, randomly assigned to either CMV or BVV groups during 90 minutes of OLV.
- Tidal volume was adjusted to 9 ml/kg during OLV after initial anesthesia.
- Hemodynamics, respiratory gases (arterial, venous, end-tidal), and respiratory mechanics were measured. Derived indices included pulmonary vascular resistance, shunt fraction, and dead space ventilation.
Main Results:
- Arterial oxygen tension was significantly higher in the BVV group during OLV (P = 0.003).
- Shunt fraction and dead space ventilation were lower with BVV from 30-90 minutes (P = 0.0004 and P = 0.0001, respectively).
- Static compliance improved with BVV by 60 minutes and remained elevated upon return to two-lung ventilation (P = 0.0001).
Conclusions:
- BVV demonstrated superior gas exchange and respiratory mechanics compared to CMV during one-lung ventilation in this porcine model.
- The benefits of BVV on static compliance persisted after restoring two-lung ventilation.
- BVV represents a promising alternative to CMV for improving patient outcomes during OLV.
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