Department of Pulmonology, Uludağ University Faculty of Medicine, Bursa, Türkiye.
Tuberk Toraks. 2022 Dec;70(4):324-333. doi: 10.5578/tt.20229603.
Noninvasive ventilation (NIV) for acute hypercapnic respiratory failure (AHRF) is an established treatment modality. Current evidence does not conclude any superiority between fixed pressure support (PS) and average volume-assured pressure support (AVAPS) modes. However, given the ability of rapid PaCO2 decline in AVAPS mode, we hypothesized that COPD patients with AHRF who did not show the desired reduction in PaCO2 with fixed-level PS-NIV might benefit from the AVAPS mode.
Patients admitted to the non-ICU pulmonary ward with acute exacerbation of COPD (AECOPD) and AHRF were included consecutively in this observational study. Patients with hypercapnic respiratory failure due to obesity-hypoventilation, neurological diseases, or chest wall deformities were excluded. All patients started NIV treatment with fixed pressure support (PS) and patients who did not reach clinical and laboratory stability under PS-NIV treatment were switched to the average volume-assured pressure support (AVAPS) mode of NIV.
Thirty-five COPD patients with hypercapnic respiratory failure were included. Under PS-NIV treatment, 14 (40%) patients showed a 17.9 (-0.0-29.2) percent change in terms of PaCO2, meaning no improvement or worsening. Therefore, these patients were treated with AVAPS mode. Arterial PaCO2 and pH levels significantly improved after AVAPS-NIV administration. AVAPS-NIV treatment created a significantly better PaCO2 change rate than using PS-NIV [-11.4 (-22.0 - -0.5) vs 8.2 (-5.3-19.5), p= 0.02]. Independent predictors of AVAPS mode requirement were higher Charlson Comorbidity Index [OR= 1.74 (95% CI= 1.02-2.97)] and higher PaCO2 upon admission [OR= 1.18 (95% CI= 1.03-1.35)]. Thirteen (92.8%) patients reaching significant clinical stability with AVAPS-NIV were able to return to fixed-level PS-NIV and maintain acceptable PaCO2 levels.
Our study demonstrated that patients can benefit from AVAPSNIV despite insufficient response to fixed-level PS-NIV.
无创通气（NIV）治疗急性高碳酸血症性呼吸衰竭（AHRF）是一种已确立的治疗方法。目前的证据并未得出固定压力支持（PS）和平均容量保证压力支持（AVAPS）模式之间存在任何优势的结论。然而，鉴于 AVAPS 模式可迅速降低 PaCO2，我们假设 AHRF 的 COPD 患者如果使用固定水平 PS-NIV 未能达到预期的 PaCO2 降低效果，可能会受益于 AVAPS 模式。
本观察性研究连续纳入因 COPD 急性加重（AECOPD）和 AHRF 而入住非 ICU 肺病病房的患者。排除因肥胖低通气、神经疾病或胸壁畸形导致高碳酸血症性呼吸衰竭的患者。所有患者均开始接受固定压力支持（PS）NIV 治疗，在 PS-NIV 治疗下未达到临床和实验室稳定的患者切换至平均容量保证压力支持（AVAPS）模式的 NIV。
共纳入 35 例合并高碳酸血症性呼吸衰竭的 COPD 患者。在 PS-NIV 治疗下，14 例（40%）患者的 PaCO2 变化率为 17.9（-0.0-29.2）%，意味着无改善或恶化。因此，这些患者接受 AVAPS 模式治疗。在接受 AVAPS-NIV 治疗后，动脉 PaCO2 和 pH 值水平显著改善。与使用 PS-NIV 相比，AVAPS-NIV 治疗可显著改善 PaCO2 变化率[-11.4（-22.0-0.5）比 8.2（-5.3-19.5），p=0.02]。需要使用 AVAPS 模式的独立预测因素包括较高的 Charlson 合并症指数[比值比（OR）=1.74（95%置信区间[CI]：1.02-2.97）]和较高的入院时 PaCO2[OR=1.18（95%CI：1.03-1.35）]。13 例（92.8%）患者在接受 AVAPS-NIV 治疗后达到显著临床稳定，能够转回固定水平 PS-NIV 并维持可接受的 PaCO2 水平。
尽管对固定水平 PS-NIV 反应不足，但患者仍可从 AVAPS-NIV 中获益。
