Cruces Pablo, Moreno Diego, Reveco Sonia, Améstica Marjorie, Araneda Patricio, Ramirez Yenny, Vásquez-Hoyos Pablo, Díaz Franco
Unidad de Paciente Crítico Pediátrico, Departamento de Pediatría, Hospital El Carmen de Maipú, Santiago, Chile.
Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile.
Pediatr Pulmonol. 2023 Oct;58(10):2899-2905. doi: 10.1002/ppul.26610. Epub 2023 Aug 18.
Accurate and reliable noninvasive methods to estimate gas exchange are necessary to guide clinical decisions to avoid frequent blood samples in children with pediatric acute respiratory distress syndrome (PARDS). We aimed to investigate the correlation and agreement between end-tidal measured immediately after a 3-s inspiratory-hold ( CO ) by capnometry and measured by arterial blood gases (ABG) in PARDS.
Prospective cohort study.
Seven-bed Pediatric Intensive Care Unit, Hospital El Carmen de Maipú, Chile.
Thirteen mechanically ventilated patients aged ≤15 years old undergoing neuromuscular blockade as part of management for PARDS.
None.
All patients were in volume-controlled ventilation mode. The regular end-tidal (without the inspiratory hold) was registered immediately after the ABG sample. An inspiratory-hold of 3 s was performed for lung mechanics measurements, recording in the breath following the inspiratory-hold. ( CO ). End-tidal alveolar dead space fraction (AVDSf) was calculated as and its surrogate (S)AVDSf as . Measurements of were considered the gold standard. We performed concordance correlation coefficient (ρc), Spearman's correlation (rho), and Bland-Altmann's analysis (mean difference ± SD [limits of agreement, LoA]). Eleven patients were included, with a median (interquartile range) age of 5 (2-11) months. Tidal volume was 5.8 (5.7-6.3) mL/kg, PEEP 8 (6-8), driving pressure 10 (8-11), and plateau pressure 17 (17-19) cm H O. Forty-one paired measurements were analyzed. was higher than (52 mmHg [48-54] vs. 42 mmHg [38-45], p < 0.01), and there were no significant differences with CO (50 mmHg [46-55], p > 0.99). The concordance correlation coefficient and Spearman's correlation between and CO were robust (ρc = 0.80 [95% confidence interval [CI]: 0.67-0.90]; and rho = 0.80, p < 0.001.), and for were weak and strong (ρc = 0.27 [95% CI: 0.15-0.38]; and rho = 0.63, p < 0.01). The bias between CO and was -0.4 ± 3.5 mmHg (LoA -7.2 to 6.4), and between and was -8.5 ± 4.1 mmHg (LoA -16.6 to -0.5). The correlation between AVDSf and (S)AVDSf was moderate (rho = 0.55, p < 0.01), and the mean difference was -0.5 ± 5.6% (LoA -11.5 to 10.5).
This pilot study showed the feasibility of measuring end-tidal CO after a 3-s end-inspiratory breath hole in pediatric patients undergoing controlled ventilation for ARDS. Encouraging preliminary results warrant further study of this technique.
准确可靠的无创气体交换评估方法对于指导临床决策、避免儿科急性呼吸窘迫综合征（PARDS）患儿频繁采集血样十分必要。我们旨在研究PARDS患儿中，通过二氧化碳描记法在3秒吸气末屏气后即刻测得的呼气末二氧化碳（EtCO₂）与动脉血气（ABG）测得的二氧化碳之间的相关性和一致性。
前瞻性队列研究。
智利迈普市埃尔卡门医院拥有7张床位的儿科重症监护病房。
13例年龄≤15岁、因PARDS接受神经肌肉阻滞治疗的机械通气患儿。
无。
所有患者均采用容量控制通气模式。在采集ABG样本后立即记录常规呼气末二氧化碳（无吸气末屏气）。进行3秒吸气末屏气以测量肺力学，在吸气末屏气后的呼吸中记录EtCO₂。呼气末肺泡死腔分数（AVDSf）计算为（[潮气量 - 二氧化碳波形图上的呼气末平台期斜率×呼气时间] / 潮气量），其替代指标（S）AVDSf计算为（[潮气量 - 二氧化碳波形图上的呼气末平台期斜率×呼气时间] / 肺泡通气量）。将ABG测得的二氧化碳值视为金标准。我们进行了一致性相关系数（ρc）、Spearman相关性分析（rho）以及Bland-Altmann分析（平均差值±标准差[一致性界限，LoA]）。纳入11例患者，中位（四分位间距）年龄为5（2 - 11）个月。潮气量为5.8（5.7 - 6.3）mL/kg，呼气末正压（PEEP）为8（6 - 8），驱动压为10（8 - 11），平台压为17（17 - 19）cmH₂O。分析了41对测量值。EtCO₂高于ABG测得的二氧化碳值（52mmHg[48 - 54]对42mmHg[38 - 45]，p < 0.01），与吸气末屏气后测得的EtCO₂（EtCO₂(3s)）无显著差异（50mmHg[46 - 55]，p > 0.99）。EtCO₂与EtCO₂(3s)之间的一致性相关系数和Spearman相关性较强（ρc = 0.80[95%置信区间[CI]：0.67 - 0.90]；rho = 0.80，p < 0.001），而EtCO₂与ABG测得的二氧化碳值之间的相关性较弱和较强（ρc = 0.27[95%CI：0.15 - 0.38]；rho = 0.
