肺炎是小儿时期最常发生的疾病之一,也是婴幼儿时期主要病死原因之一。这主要与小儿的呼吸系统解剖、生理、免疫学特点有关。一、解剖学特点:小儿气管、支气管管腔狭窄,对通气不利;粘液分泌较少、气道干燥、纤毛运动差不利于微生物的排出。当感染时气管粘膜充血水肿,使呼吸道狭窄更明显,分泌物更不易排出,阻塞气道造成通气障碍甚至肺不张。肺弹力组织发育差,间质发育相对较好且血管丰富,而肺泡数目较少,所以小儿时期易患间质性肺炎且肺瘀血明显。小儿胸腔呈短圆桶状,肺脏组织相对较大,几乎填满整个胸腔,因此肺的扩张受到限制,对气体的交换不利。二、生理学特点:小儿时期肺脏相对地小,潮气 Pneumonia is one of the most common diseases in infancy and one of the major causes of death in infancy. This is mainly related to pediatric respiratory anatomy, physiology, immunology characteristics. First, the anatomical features: Pediatric trachea, bronchial stenosis, adverse ventilation; mucus secretion less dry airway, cilia movement is not conducive to the discharge of microorganisms. Tracheal congestion and edema when the infection, the respiratory tract stenosis more obvious secretions more difficult to discharge, obstruction of the airway caused by ventilation disorders or atelectasis. Pulmonary elastic tissue development is poor, interstitial development is relatively good and rich in blood vessels, while the number of alveoli, so susceptible to interstitial pneumonia in childhood and lung blood stasis. Pediatric chest was a short barrel, the lung tissue is relatively large, almost filling the entire chest, so the expansion of the lung is limited, adverse gas exchange. Second, the physiological characteristics: relatively small lungs in infancy, moisture