Department of Anesthesiology and Pain Medicine, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, South Korea.
Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, South Korea.
Paediatr Anaesth. 2022 Jun;32(6):754-763. doi: 10.1111/pan.14437. Epub 2022 Mar 20.
Intraoperative hypercapnia and hypocapnia are common during pediatric anesthesia, and the cerebral blood flow and intracranial pressure may be affected by the partial pressure of arterial carbon dioxide. Transorbital ultrasound measurement of the optic nerve sheath diameter is a simple and non-invasive method for intracranial pressure assessment. The objective of this study was to evaluate the effect of end-tidal carbon dioxide (E CO ) on optic nerve sheath diameter in a healthy anesthetized pediatric population.
Pediatric patients scheduled for elective surgery under general anesthesia and mechanical ventilation in the supine position were enrolled and divided into four subgroups; age <2 years, 2-6 years, 6-12 years, and 12-18 years. Mechanical ventilation was adjusted to achieve target E CO levels in a randomized sequence (40-35-45-40 mmHg or 40-45-35-40 mmHg). Three minutes after reaching each target E CO level, transorbital ultrasound images of optic nerve sheath diameter were obtained and analyzed. The primary outcome was the optic nerve sheath diameter at each E CO level.
Sixty-four pediatric patients were enrolled and analyzed. At E CO = 40 mmHg, the optic nerve sheath diameter was 5.6 ± 0.6 mm, 6.4 ± 0.5 mm, 6.8 ± 0.6 mm, and 7.1 ± 0.5 mm in children aged <2 years, 2-6 years, 6-12 years, and 12-18 years, respectively. The overall percent decreases in the optic nerve sheath diameter was -5.6 ± -4.3% (95% CI; -6.7 to -4.5%) at E CO = 35 mmHg while the overall percent increases of optic nerve sheath diameter (ONSD) was 4.9 ± 5.1% (95% CI; 3.6 to 6.1%) at E CO = 45 mmHg compared with those at E CO = 40 mmHg. Spearman rank correlation analysis indicated that there were weak to moderate correlation between E CO and the optic nerve sheath diameter (correlation coefficient [p-value] = .355 [.004], .318 [.014], .373 [<.001], and .420 [<.001] in children aged <2 years, 2-6 years, 6-12 years, and 12-18 years, respectively).
The optic nerve sheath diameter measured by transorbital ultrasound showed rapid reactivity from E CO 35 to 45 mmHg in healthy pediatric patients under inhalation general anesthesia.
在小儿麻醉期间，术中高碳酸血症和低碳酸血症很常见，动脉二氧化碳分压可能会影响脑血流和颅内压。经眶超声测量视神经鞘直径是一种简单且无创的颅内压评估方法。本研究旨在评估健康麻醉小儿人群中呼气末二氧化碳（E CO ）对视神经鞘直径的影响。
本研究纳入了在全身麻醉和机械通气下接受择期手术的小儿患者，并按年龄分为 4 个亚组；<2 岁、2-6 岁、6-12 岁和 12-18 岁。机械通气调整至随机序列中的目标 E CO 水平（40-35-45-40mmHg 或 40-45-35-40mmHg）。在达到每个目标 E CO 水平 3 分钟后，获取经眶超声视神经鞘直径图像并进行分析。主要结局是每个 E CO 水平的视神经鞘直径。
本研究共纳入 64 名小儿患者并进行了分析。在 E CO 为 40mmHg 时，<2 岁、2-6 岁、6-12 岁和 12-18 岁的儿童视神经鞘直径分别为 5.6±0.6mm、6.4±0.5mm、6.8±0.6mm 和 7.1±0.5mm。当 E CO 为 35mmHg 时，视神经鞘直径的总体百分比下降为-5.6±-4.3%（95%CI；-6.7 至-4.5%），而当 E CO 为 45mmHg 时，视神经鞘直径的总体百分比增加为 4.9±5.1%（95%CI；3.6 至 6.1%），与 E CO 为 40mmHg 时相比。Spearman 秩相关分析表明，E CO 与视神经鞘直径之间存在弱到中度相关性（相关系数[P 值]分别为.355[<.001]、.318[.014]、.373[<.001]和.420[<.001]）。
在吸入全身麻醉下的健康小儿患者中，经眶超声测量的视神经鞘直径对 E CO 从 35mmHg 到 45mmHg 的变化反应迅速。
