吸气肌储备功能的测定及其临床意义

Measurement of the Reserve Function of Inspiratory Muscle and Its Clinical Significance

探讨了吸气肌张力－时间指数（ＴＴｉ＿ｍ）、吸气功（Ｗｉ）／最大吸气功（Ｗｉ＿（ｍａｘ））的测定原理和计算公式，并对３５例肺通气功能正常者与８９例慢性阻塞性肺病（ＣＯＰＤ）患者进行了ＴＴｉ＿ｍ、Ｗｉ／Ｗｉ＿（ｍａｘ）测定。结果表明：ＴＴｉ＿ｍ和Ｗｉ／Ｗｉ＿（ｍａｘ）与吸气压（Ｐｉ）／最大吸气压（Ｐｉ＿（ｍａｘ））呈显著正相关，且ＣＯＰＤ患者ＴＴｉ＿ｍ与Ｗｉ／Ｗｉ＿（ｍａｘ）均随病情严重程度而递增，与正常组的差异有显著性。据此，作者认为ＴＴｉ＿ｍ与Ｗｉ／Ｗｉ＿（ｍａｘ）可作为反映吸气肌储备功能的指标。

The principles of measuring inspiratory muscle tension-time index(TTi_m)and the ratio of the works of inspiration over the maximal works of inspi-ration(Wi/Wi_(max)) were investigated and their formu-lae were deduced,i.e. TTi_m=(Pi× Ti)/(MIP ×T_(tot))and Wi/Wi_(max)=(Pi×V_T)/(MIP×IC).The impor-tance of the inspiratory pressure and the maximal in-spiratory pressure(MIP)measured at function residu-al capacity(FRC)level was emphasized.Both TTi_m and Wi/Wi_(max) were measured in 35 normal subjects and 89 patients with chronic obstructive pulmonary disease(COPD).The results showed that normal value of TTi_m was 0.025±0. 0055 which corresponds to thenormal value of the diaphragm tension-time index(TTdi=0.02-0.03)reported by Bellemare. Patientswith COPD had a mean TTi_m much higher than that ofnormals (P<0.01 ).The works of inspiration(Wi)inpatients with COPD increased,while the maximalworks of inspiration(Wi_(max)) declined , so Wi/Wi_(max) be-came significantly greater than that of normals(P<0.01 ). The results also showed that there was a linearrelationship between Pi/Pi_(max) and TTi_m or Wi/Wi_(max)(r=0. 7891.0.9738,0.6459,0.9327,P<0.01).There-fore, we suggest that both TTi_m and Wi/Wi_(max) can beused as clinical indices to reflect the reserve function ofinspiratory muscles.