One lung ventilation (OLV) is essential during thoracic surgery. During OLV, intrapulmonary shunt can be increased resulting hypoxemia. Wang et al measured intrapulmonary shunt by transesophageal echocardiography. Although OLV technique had been advanced so far, hypoxemia during OLV reaches about 10% in spite of inspired oxygen fraction 100%. Applying PEEP(Positive End-expiratory Pressure) at dependent lung and CPAP at non-dependent lung can mitigate the hypoxemia. Above all, PEEP can be easily applicable. However, there are controversial studies whether it is supportive or not. In this prospective, cross-over study, the investigators are planning to investigate the effects of PEEP on intrapulmonary shunt, oxygenation and cardiac function as well.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
DIAGNOSTIC
Masking
DOUBLE
Enrollment
36
After induction of anesthesia, including insertion of TEE probe, change position from supine to lateral position. Measure ABGA and cardiac indices for the baseline value. Apply each PEEP (0, 5, 10 cmH2O) serially at the random order. 6 sequences (0-\>5-\>10, 0-\>10-\>5, 5-\>10-\>0, 5-\>0-\>10, 10-\>5-\>0, 10-\>0-\>5) are equally applied to 6 patients (total 6x6=36 patients) who agreed to this study. Measure ABGA and cardiac indices after 20 min at each step of peep apply(3 times).
Department of Anaesthesiology and Pain Medicine, Anaesthesia and Pain Research Institute, Yonsei University College of Medicine
Seoul, South Korea
the effect of differential PEEP (0, 5, 10 cmH2O) by PaO2(P/F ratio)
Time frame: 20 minutes after each PEEP apply
Cardiac function
cardiac function : Tei index
Time frame: 20 minutes after each PEEP apply
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