Mylavarapu Goutham, Fleck Robert J, Ok Michale S, Ding Lili, Kandil Ali, Amin Raouf S, Das Bobby, Mahmoud Mohamed
Cincinnati Children's Hospital Medical Center, Division of Pulmonary Medicine, Cincinnati, OH 45229, USA.
Cincinnati Children's Hospital Medical Center, Department of Radiology, Cincinnati, OH 45229, USA.
J Clin Med. 2020 Nov 20;9(11):3723. doi: 10.3390/jcm9113723.
General anesthesia decreases the tone of upper airway muscles in a dose-dependent fashion, potentially narrowing the pharyngeal airway. We examined the effects of adding ketamine on the airway configuration after dexmedetomidine administration in spontaneously breathing children with normal airways. 25 children presenting for Magnetic Resonance Imaging (MRI) of the brain/spine under general anesthesia were prospectively recruited in the study. Patients were anesthetized with dexmedetomidine bolus (2 mcg over 10 min) followed by dexmedetomidine infusion (2 mcg·kg-1·h) and ketamine and permitted to breathe spontaneously via the native airway. MR-CINE images of the upper airway were obtained with dexmedetomidine infusion alone (baseline) and 5, 10, and 15 min after administering ketamine bolus (2 mg·kg-1) in two anatomical axial planes at the nasopharynx and the retroglossal upper airway. Airway lumen is segmented with a semi-automatic image processing approach using a region-growing algorithm. Outcome measures of cross-sectional area, transverse and anterior-posterior diameters of the airway in axial planes at the level of the epiglottis in the retroglossal airway, and in the superior nasopharynx were evaluated for changes in airway size with sedation. Airway dimensions corresponding to the maximum, mean, and minimum sizes during a respiratory cycle were obtained to compare the temporal changes in the airway size. The dose-response of adding ketamine to dexmedetomidine alone condition on airway dimensions were examined using mixed-effects of covariance models. 22/25 patients based on inclusion/exclusion criteria were included in the final analysis. The changes in airway measures with the addition of ketamine, when compared to the baseline of dexmedetomidine alone, were statistically insignificant. The modest changes in airway dimensions are clinically less impactful and within the accuracy of the semi-automatic airway segmentation approach. The effect sizes were small for most airway measures. The duration of ketamine seems to not affect the airway size. In conclusion, adding ketamine to dexmedetomidine did not significantly reduce upper airway configuration when compared to dexmedetomidine alone.
全身麻醉会以剂量依赖的方式降低上呼吸道肌肉的张力，有可能使咽气道变窄。我们研究了在气道正常的自主呼吸儿童中，给予右美托咪定后添加氯胺酮对气道形态的影响。本研究前瞻性纳入了25例在全身麻醉下进行脑/脊柱磁共振成像（MRI）的儿童。患者先静脉注射右美托咪定（10分钟内注射2μg），随后持续输注右美托咪定（2μg·kg-1·h）和氯胺酮，并允许通过自然气道自主呼吸。在两个解剖轴向平面（鼻咽部和舌后上气道），在单独输注右美托咪定（基线）时以及静脉注射氯胺酮（2mg·kg-1）后5、10和15分钟获取上气道的MR-CINE图像。使用区域生长算法通过半自动图像处理方法对气道腔进行分割。评估了舌后气道会厌水平轴向平面以及鼻咽上部气道的气道横截面积、横向和前后径等结局指标，以观察镇静状态下气道大小的变化。获取呼吸周期中对应最大、平均和最小尺寸的气道维度，以比较气道大小的时间变化。使用协方差模型的混合效应研究了在单独使用右美托咪定的情况下添加氯胺酮对气道维度的剂量反应。根据纳入/排除标准，最终分析纳入了22/25例患者。与单独使用右美托咪定的基线相比，添加氯胺酮后气道测量值的变化无统计学意义。气道维度的适度变化在临床上影响较小，且在半自动气道分割方法的精度范围内。大多数气道测量指标的效应大小较小。氯胺酮的使用时间似乎不影响气道大小。总之，与单独使用右美托咪定相比，添加氯胺酮并未显著减小上气道形态。
