Use of carbon dioxide production to detect bacterial superinfections in mechanically ventilated patients with acute respiratory distress syndrome: an exploratory prospective cohort study.

IF 3.4 3区医学 Q1 RESPIRATORY SYSTEM

BMJ Open Respiratory Research Pub Date : 2025-08-28 DOI:10.1136/bmjresp-2024-002760

Nicole S Strickler, Daniel A Hofmaenner, Reto A Schuepbach, Thomas C Scheier, Philipp K Buehler, Jukka Takala, Silvio D Brugger, Pascal M Frey

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Abstract

Background: Bacterial superinfections are common in patients with acute respiratory distress syndrome (ARDS) but diagnosing them is challenging. Exhaled carbon dioxide (V'CO2) may be increased during bacterial infection, suggesting a potential marker for detecting bacterial superinfections in ARDS patients.

Methods: In a prospective cohort study of mechanically ventilated adult patients with ARDS due to SARS-CoV-2 in a tertiary intensive care unit, we assessed V'CO2 measurements from continuous volumetric capnography and calculated daily median V'CO2 levels. The primary outcome was to determine if a first substantial increase in daily median V'CO2 was associated with a first bacterial superinfection. Protocolised microbiological sampling and adjudicated clinical interpretations were used to determine the onset of a first superinfection.

Results: A total of 150 days of continuous volumetric capnography were analysed in 31 mechanically ventilated adult patients with ARDS due to SARS-CoV-2. We observed 10 patients (32%) with a first episode of substantial increase of daily median V'CO2, and 12 (39%) patients with a first bacterial superinfection. A V'CO2 increase was not associated with a superinfection on the same day (OR 3.47, 95% CI 0.64 to 18.92, p=0.15, adjusted for age and gender). Investigating all 150 test days of median V'CO2 revealed a poor sensitivity (17%, 95% CI 2% to 48%) for detecting superinfections. However, a first V'CO2 increase indicated superinfection with high specificity (94%, 95% CI 89% to 98%). Patients with superinfections showed higher daily median V'CO2 levels (210 mL/min) than those without (176 mL/min, p<0.001), even after adjusting for age and gender (OR 1.56, 95% CI 1.16 to 2.08, p=0.003).

Conclusions: A sudden increase in daily median V'CO2 did not reliably detect bacterial superinfections, which was reflected in a poor sensitivity and inability to rule out superinfections in patients without V'CO2 increase. Nevertheless, high specificity suggests that V'CO2 may be useful to rule in superinfections in patients with ARDS.

Trial registration number: NCT04410263.

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利用二氧化碳产生检测急性呼吸窘迫综合征机械通气患者的细菌超感染：一项探索性前瞻性队列研究

背景：细菌重复感染在急性呼吸窘迫综合征（ARDS）患者中很常见，但诊断具有挑战性。细菌感染期间呼出的二氧化碳（V'CO2）可能增加，提示检测ARDS患者细菌重复感染的潜在标记物。方法：在一项对三级重症监护病房中因SARS-CoV-2而机械通气的成年ARDS患者进行的前瞻性队列研究中，我们评估了连续容积造影的V'CO2测量值，并计算了每日中位V'CO2水平。主要结果是确定每日中位数V'CO2的首次大幅增加是否与首次细菌重复感染有关。使用协议规定的微生物取样和裁定的临床解释来确定首次重复感染的发病。结果：对31例经机械通气的成人SARS-CoV-2型急性呼吸窘迫综合征（ARDS）患者进行了150天连续容积造影分析。我们观察到10例（32%）患者首次发作时每日中位V'CO2显著升高，12例（39%）患者首次出现细菌重复感染。V'CO2升高与同一天的重复感染无关（OR 3.47, 95% CI 0.64 ~ 18.92, p=0.15，经年龄和性别调整）。调查中位数V'CO2的所有150个测试天显示，检测重复感染的敏感性较差（17%，95% CI为2%至48%）。然而，首次V'CO2升高表明重复感染具有高特异性（94%，95% CI 89%至98%）。重复感染患者的每日中位V'CO2水平（210 mL/min）高于无重复感染患者（176 mL/min）。结论：每日中位V'CO2水平突然升高并不能可靠地检测细菌重复感染，这反映在V'CO2未升高患者的敏感性较差且无法排除重复感染。然而，高特异性表明，V'CO2可能有助于控制ARDS患者的重复感染。试验注册号：NCT04410263。

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来源期刊

BMJ Open Respiratory Research RESPIRATORY SYSTEM-

CiteScore

6.60

自引率

2.40%

发文量

审稿时长

12 weeks

期刊介绍： BMJ Open Respiratory Research is a peer-reviewed, open access journal publishing respiratory and critical care medicine. It is the sister journal to Thorax and co-owned by the British Thoracic Society and BMJ. The journal focuses on robustness of methodology and scientific rigour with less emphasis on novelty or perceived impact. BMJ Open Respiratory Research operates a rapid review process, with continuous publication online, ensuring timely, up-to-date research is available worldwide. The journal publishes review articles and all research study types: Basic science including laboratory based experiments and animal models, Pilot studies or proof of concept, Observational studies, Study protocols, Registries, Clinical trials from phase I to multicentre randomised clinical trials, Systematic reviews and meta-analyses.