极低出生体重儿医院感染的临床特点及早期诊断

Clinical characterization and early diagnosis of nosocomial infection in very low birth weight infants

目的 探讨极低出生体重儿（very low birth weight infant，VLBWI）医院感染的临床特点，以期做到早诊断、早治疗。方法 对1996年1月至2005年12月间于生后24h内转入我院新生儿重症监护病房（neonatal intensive care unit，NICU）的226例VLBWI医院感染发生情况进行回顾性分析。结果 本组226例VLBWI发生医院感染59例共81次，医院感染发生率为26．1％（59／226）。胎龄越小，体重越低，医院感染发生率越高。81例次医院感染的疾病或定位分布主要为：败血症25例次（30．9％），菌血症10例次（12．3％），呼吸道感染21例次（25．9％），胃肠道感染8例次（9．9％）等。医院感染首次发生时间多为生后2～3周。67例次医院感染（除外皮肤感染、结膜炎、脐炎、鹅口疮）早期临床表现主要为：呼吸暂停重现或频率增加25例；呼吸增快16例；呼吸支持增加或呼吸机参数需调高8例；发热或体温不升12例；喂养不耐受或腹胀8例；嗜睡和肌张力减低6例。白细胞计数异常或杆状核细胞与中性粒细胞比值升高（≥0．16）27例；血小板计数降低11例；血糖稳定后又突然出现高血糖20例；难以解释的代谢性酸中毒12例；动脉二氧化碳分压增高7例。从59例患儿106份血液、尿液、脑脊液或气管插管内吸引物标本培养分离病原菌38株，其中革兰阳性球菌21株，革兰阴性杆菌17株。结论 医院感染VLBWI发生率高、临床表现多样、病情进展迅速，因此临床应采取合理的预防措施并密切观察病情以做到早发现、早治疗。

Objective To study the clinical characterization and early diagnosis of nosocomial infection in very low birth weight infants （VLBWI）. Methods Clinical data of 226 VLBWI admitted to neonatal intensive care unit （NICU） within 24 hours after birth were retrospectively analyzed for nosoeomial infection from January 1996 to December 2005. Results Fifty-nine （26. 1M） VLBWI had a total of 81 documented nosocomial infections. The morbidity of nosocomial infection increased with decreasing birth weight or gestation age （P〈0.01）. Sepsis （defined and suspected） were responsible for 25 （30.9%） of the 81 episodes of nosocomial infection and bacteremia for 10 （12.3%）, 21 （25.9M） infections involved the respiratory tract and 8 （9.9%） involved the gastrointestinal tract, 3 （3.7%） involved the urinary tract; 5 （6.2 %） skin infections, 4 （4.9%） thrushs, 3 （3.7%） conjunctivitis and 2 （2.5%） omphalitis. Most of the onset for the first episode was near 2-3 weeks after birth. Early clinical presentation of 67 episodes of nosocomial infection （excluding skin infections, conjunctivitis, omphalitis and thrush） included： re-occurrence of apnea or increasing frequency of apnea （25 cases）, tachypnea （16 cases）, increased respiratory support （8 cases）, abnormal body temperature （12 cases）, feeding intolerance or abdominal distension （8 cases）, lethargy and hypotonia （6 cases）, abnormal white blood cell count （27 cases）, decreased platelet count （11 cases）, hyperglycemia following a period of normoglycemia （20 cases）, unexplained metabolic acidosis （12 cases）, increased PaCO2 （7 cases）. Thirty-eight pathogens were isolated from 59 patients （blood, urine, cerebrospinal fluid and bronchioalveolar fluid）, with 21 strains of Gram-positive bacilli and 17 strains of Gram-negative bacilli. Conclusions The incidence of nosocomial infection in VLBWI remains high. For initial clinical signs are nonspecific, nosocomial infection should be considered while one or more abnormal clinical symptoms/laboratory findings occur in VLBWI during admission, and additional specific investigations must be done in order to make early diagnosis and take intervention measures in time.