When switcheing from TLV to OLV in correct DLT position,Ppeak increased by 50.8% and lung compliance decreased by 36.2%,which were even greater and the slope of P-V curve was reduced and the P-V loop prolonged when DLTs were inserted too deap.

• S2时Ppeak值比S1时增加 5 0 8%25 ,肺顺应性 (Cdyn)值减少 36 2%25 ; S3 时Ppeak值比S1时增加 87 4%25 ,Cdyn值减少 5 6 8%25。