Downing G J, Kilbride H W
NICHD Endocrine and Reproductive Research Branch, National Institutes of Health, Bethesda, Maryland, USA.
Pediatrics. 1995 Apr;95(4):567-72.
We sought to determine factors that would predict the development of subglottic stenosis (SGS) and tracheomalacia (TM) in preterm infants. The utility of a semiquantitative measurement of airway dimensions was assessed in relation to signs of airway complications. We also sought to determine from a high-risk population of infants those likely to have abnormal findings identified by bronchoscopic examination.
Prospective airway endoscopy was performed for preterm infants who were intubated for 7 days or more or who demonstrated chronic oxygen needs beyond 28 days after birth and 36 weeks postconceptional age. Subjects were 117 preterm (less than 36 weeks' gestation) infants from two level III intensive care nurseries. Endoscopy was used to classify the type and degree of airway injury. Subglottic stenosis was defined subjectively and compared with an objective measurement using subglottic spatial relations described as a trans-subglottic/vocal cord ratio (TSG/VC). Clinical signs and symptoms and other risk factors were evaluated as significant predictors of SGS and TM, identified by bronchoscopy.
Moderate or severe airway abnormalities were identified in 32 patients (27.3%); 13 with SGS, 17 with TM, and 2 with both. All but one infant with TSG/VC less than 0.83 had signs and symptoms of airway dysfunction. Variables more commonly found in patients with SGS included greater number of intubations, use of inappropriately large endotracheal tubes, and longer duration of intubation. Higher averaged mean airway pressure during the first week after birth and lower gestational age were clinical features associated with TM.
Flexible bronchoscopic evaluation of a high-risk population demonstrated a higher incidence of moderate or severe SGS or TM than previously suspected. Subglottic stenosis and TM appear to have different etiologies based on different factors associated with their development. The TSG/VC ratio correlated well with obstructive symptoms and may represent a means to quantitate clinically subglottic narrowing. Infants with chronic lung disease who have persistently elevated partial pressure of carbon dioxide, apnea, or phonation abnormalities are most likely to have airway abnormalities identifiable by bronchoscopy.
我们试图确定可预测早产儿声门下狭窄（SGS）和气管软化（TM）发生的因素。评估气道尺寸半定量测量与气道并发症体征的相关性。我们还试图从高危婴儿群体中确定那些可能通过支气管镜检查发现异常结果的婴儿。
对插管7天或更长时间或出生后28天及孕龄36周后仍有慢性氧需求的早产儿进行前瞻性气道内镜检查。研究对象为来自两个三级重症监护病房的117例早产（妊娠小于36周）婴儿。内镜检查用于对气道损伤的类型和程度进行分类。声门下狭窄通过主观定义，并与使用声门下空间关系（描述为声门下/声带比例，TSG/VC）的客观测量结果进行比较。评估临床体征和症状以及其他危险因素，作为支气管镜检查确定的SGS和TM的重要预测指标。
32例患者（27.3%）发现中度或重度气道异常；13例患有SGS，17例患有TM，2例两者皆有。除1例TSG/VC小于0.83的婴儿外，所有婴儿均有气道功能障碍的体征和症状。SGS患者中更常见的变量包括插管次数更多、使用尺寸不合适的气管内导管以及插管持续时间更长。出生后第一周平均气道压较高和胎龄较低是与TM相关的临床特征。
对高危人群进行的柔性支气管镜评估显示，中度或重度SGS或TM的发生率高于先前的怀疑。声门下狭窄和TM似乎基于与其发生相关的不同因素而有不同的病因。TSG/VC比例与阻塞性症状相关性良好，可能代表一种临床定量声门下狭窄的方法。患有慢性肺病且二氧化碳分压持续升高、呼吸暂停或发声异常的婴儿最有可能通过支气管镜检查发现气道异常。
