解剖学的残存肺容積率による肺葉切除後の予測呼吸機能評価

Assessment of Predicted Post-lobectomy Lung Function by Means of a New Method of Anatomical Residual Lung Volume Ratio

要旨　【目的】肺葉切除162例の解剖学的残存肺容積率(ARVR)により算出された予測値(ppo)と，術後の呼吸機能による実測値(act)を比較し有効性を検討した．【方法】術前VC，FEV₁，DLcoに右1区域を5.5，左1区域を5.0，全体を100とした残存肺容積率からppoを算出した．【結果】術前呼吸機能正常群90例のppoとactの相関係数はVCが0.91，FEV₁が0.90，DLcoが0.87と強い相関を示し回帰直線もほぼy＝xに近かった．慢性期にはppo＜actとなり，残存肺の予備能力あるいは過膨張を反映していた．COPD合併49例ではVCが0.89，FEV₁は0.86，DLcoは0.76であり，急性期ppo＞actとDLcoの低下が特に強かった．volume reduction効果は慢性期に出現していた．【結論】ARVRにより計算されたppoはactと有意な相関関係が認められ，術式決定や呼吸管理の要点を明確化することが可能と考えられた．

Normally, the right lung accounts for 55% of total lung function and consists of 10 segments, however, the left lung does 45% and 9 segments. Accordingly, by means of an anatomical residual lung volume ratio(ARVR:ex. 1-rt. removed segment number×5.5/100, 1-lt. removed segment number×5.0/100)predicted post-operative(ppo-)F(F:VC, FEV₁, and DLco)values were calculated and compared to post-operative actual measurement(act-)F values. Furthermore one-to-one correspondence of ppo-F and act-F, which factor was very important to assess the validity of a ppo-F, was compared between normal group and COPD group. The result showed the very strong correlations existed between ppo-F and act-F in normal group(n＝90 VC:r＝0.91, FEV₁:r＝0.90, DLco:r＝0.87), and the strong correlations in COPD group(n＝49 VC:r＝0.89, FEV₁:r＝0.86, DLco:r＝0.76). Tendency of a change with passage of time approximately showed in acute phase ppo-F＞act-F, in sub-acute ppo-F≒act-F, in chronic ppo-F＜act-F. One-to-one correspondence was indicated in sub-acute and/or in chronic phase. This study implied that in acute postoperative phase patients with poor lung functions(especially DLco)might need a proper treatment. On the basis of these predicted values, a scheduled procedure should be changed to limited operation owing to poor lung functions.