Rasheed Sarwat, Javed Sidra, Rasheed Thanyat, Farman Shaiza, Shalim Elisha
Sindh Infectious Disease Hospital and Research Centre, Karachi, Pakistan.
Dow University of Health Sciences, Karachi, Pakistan.
J Crit Care Med (Targu Mures). 2025 Jan 31;11(1):44-53. doi: 10.2478/jccm-2025-0004. eCollection 2025 Jan.
Acute respiratory distress syndrome (ARDS) is characterized by progressive lung inflammation which leads to increased dead space that can cause hypercapnia and can increase the risk of patient morbidity and mortality. In an attempt to improve ARDS patient outcomes provision of protective lung ventilation has been shown to improve patient mortality but increases the incidence of hypercapnia. Therefore, the role of carbon dioxide in ARDS remains contradicted by conflicted evidence. This study aims to examine this conflicting relationship between hyper-capnia and mortality in mechanically ventilated COVID-19 ARDS patients.
We conducted a retrospective cohort study. The data was collected from the medical records of the patients admitted with COVID-19 ARDS in Sindh Infectious Disease Hospital & Research Centre (SIDH & RC) from August 2020 to August 2022 and who received mechanical ventilation for more than 48 hours. The patients were grouped into severe and no severe hypercapnia groups based on their arterial blood carbon dioxide levels (PaCO2). To understand the effect of hypercapnia on mortality we performed multivariable logistic regression, and inverse probability-weighted regression to adjust for time-varying confounders.
We included 288 patients to detect at least 3% of the effect on mortality. Our analysis revealed an association of severe hypercapnia with severe lung injury, low PaO2/FiO2, high dead space, and poor compliance. In univariate analysis severe hypercapnia showed higher mortality: OR=3.50, 95% CI (1.46-8.43). However, after, adjusting for disease severity hypercapnia is not found to be associated with mortality: OR=1.08, 95% CI (0.32-3.64). The sensitive analysis with weighted regression also shows no significant effect on mortality: OR=1.04, 95% CI (0.95-1.14).
This study showed that hypercapnia is not associated with mortality in COVID-19 ARDS patients.
急性呼吸窘迫综合征（ARDS）的特征是进行性肺炎症，这会导致无效腔增加，进而引起高碳酸血症，并增加患者发病和死亡风险。为改善ARDS患者的预后，采用保护性肺通气已被证明可降低患者死亡率，但会增加高碳酸血症的发生率。因此，二氧化碳在ARDS中的作用仍存在相互矛盾的证据。本研究旨在探讨机械通气的COVID-19 ARDS患者中高碳酸血症与死亡率之间这种相互矛盾的关系。
我们进行了一项回顾性队列研究。数据收集自2020年8月至2022年8月在信德传染病医院及研究中心（SIDH & RC）收治的COVID-19 ARDS患者的病历，这些患者接受机械通气超过48小时。根据患者的动脉血二氧化碳水平（PaCO2）将其分为严重高碳酸血症组和非严重高碳酸血症组。为了解高碳酸血症对死亡率的影响，我们进行了多变量逻辑回归和逆概率加权回归，以调整随时间变化的混杂因素。
我们纳入了288例患者，以检测至少3%的死亡率影响。我们的分析揭示了严重高碳酸血症与严重肺损伤、低PaO2/FiO2、高无效腔和低顺应性之间的关联。在单变量分析中，严重高碳酸血症显示出较高的死亡率：OR = 3.50，95% CI（1.46 - 8.43）。然而，在调整疾病严重程度后，未发现高碳酸血症与死亡率相关：OR = 1.08，95% CI（0.32 - 3.64）。加权回归的敏感性分析也显示对死亡率无显著影响：OR = 1.04，95% CI（0.95 - 1.14）。
本研究表明，COVID-19 ARDS患者的高碳酸血症与死亡率无关。
