BACKGROUND Preoperative inspiratory muscle training (IMT) is frequently used in patients waiting for major surgery to improve respiratory muscle function and to reduce the risk of postoperative pulmonary complications (PPCs). Currently, the mechanism of action of IMT in reducing PPCs is still unclear. Therefore, we investigated the associations between preoperative IMT variables and the occurrence of PPCs in patients with esophageal cancer. METHODS A multi-center cohort study was conducted in subjects scheduled for esophagectomy, who followed IMT as part of a prehabilitation program. IMT variables included maximum inspiratory pressure (PImax) before and after IMT and IMT intensity variables including training load, frequency, and duration. Associations between PImax and IMT intensity variables and PPCs were analyzed using independent samples t tests and logistic regression analyses, corrected for age and pulmonary comorbidities and stratified for the occurrence of anastomotic leakages. RESULTS Eighty-seven subjects were included (69 males; mean age 66.7 ± 7.3 y). A higher PImax (odds ratio 1.016, P = .07) or increase in PImax during IMT (odds ratio 1.020, P = .066) was not associated with a reduced risk of PPCs after esophagectomy. Intensity variables of IMT were also not associated (P ranging from .16 to .95) with PPCs after esophagectomy. Analyses stratified for the occurrence of anastomotic leakages showed no associations between IMT variables and PPCs. CONCLUSIONS This study shows that an improvement in preoperative inspiratory muscle strength during IMT and training intensity of IMT were not associated with a reduced risk on PPCs after esophagectomy. Further research is needed to investigate other possible factors explaining the mechanism of action of preoperative IMT in patients undergoing major surgery, such as the awareness of patients related to respiratory muscle function and a diaphragmatic breathing pattern.

中文翻译：

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食管癌患者术前吸气肌训练变量与术后肺部并发症之间的关联。

背景技术术前吸气肌训练（IMT）经常用于等待大手术的患者，以改善呼吸肌功能并降低术后肺部并发症（PPC）的风险。目前，IMT降低PPCs的作用机制仍不清楚。因此，我们研究了食管癌患者术前 IMT 变量与 PPC 发生之间的关联。方法 对计划接受食管切除术的受试者进行了一项多中心队列研究，这些受试者将 IMT 作为预康复计划的一部分。IMT 变量包括 IMT 前后的最大吸气压力 (PImax) 和 IMT 强度变量，包括训练负荷、频率和持续时间。使用独立样本 t 检验和逻辑回归分析来分析 PImax 和 IMT 强度变量与 PPC 之间的关联，校正年龄和肺部合并症，并对吻合口漏的发生进行分层。结果 纳入 87 名受试者（69 名男性；平均年龄 66.7 ± 7.3 岁）。较高的 PImax（比值比 1.016，P = .07）或 IMT 期间 PImax 的增加（比值比 1.020，P = .066）与食管切除术后 PPC 风险降低无关。IMT 的强度变量也与食管切除术后的 PPC 无关（P 范围为 0.16 至 0.95）。针对吻合口漏发生的分层分析显示 IMT 变量与 PPC 之间没有关联。结论 这项研究表明，术前 IMT 期间吸气肌力量和 IMT 训练强度的改善与食管切除术后 PPC 风险降低无关。需要进一步研究来调查解释接受大手术的患者术前 IMT 作用机制的其他可能因素，例如患者对呼吸肌功能和膈式呼吸模式相关的意识。