Gray J E, Richardson D K, McCormick M C, Goldmann D A
Joint Program in Neonatology (Brigham and Women's Hospital, Children's Hospital, Beth Israel Hospital, and Harvard Medical School), Boston, MA02115.
Pediatrics. 1995 Feb;95(2):225-30.
To examine the impact of admission-day illness severity on nosocomial bacteremia risk after consideration of traditional risk determinants such as birth weight and length of stay.
The hospital courses for 302 consecutive very low birth weight (less than 1500 g) infants admitted to two neonatal intensive care units were examined for the occurrence of nosocomial coagulase-negative staphylococcal bacteremia. Using both cumulative incidence and incidence density as measures of bacteremia risk, we explored the relation between illness severity (as measured by the Score for Neonatal Acute Physiology [SNAP]) and bacteremia both before and after birth weight adjustment. In addition, the effect of bacteremia on hospital resource use was estimated.
Coagulase-negative staphylococcus was the most common pathogen noted in blood cultures drawn at 48 hours after admission or later. It was isolated on at least one occasion in 53 patients (cumulative incidence of 17.5 first episodes per 100 patients). These episodes occurred during 7652 days at risk, giving an incidence density of 6.9 initial bacteremias per 1000 patient-days at risk. As expected, when compared with the nonbacteremic group, bacteremic patients were of lower birth weight (888 +/- 231 vs 1127 +/- 258 g; P < .01) and gestational age (26.4 +/- 2.1 vs 28.9 +/- 2.8 weeks; P < .01). In addition, these patients were more severely ill on admission (SNAP 17.3 +/- 6.5 vs 12.2 +/- 5.8; P < .01). Even after birth weight stratification, the risk of bacteremia by both measures increased with higher SNAP scores. For example, among infants with birth weights greater than 1 kg, 25% of the most severely ill patients (SNAP 20 and higher) experienced at least one bacteremic episode, whereas the rates seen in infants with intermediate (SNAP 10 to 19) and low illness severity (SNAP 0 to 9) were 8.6% and 3.0%, respectively (chi 2 for trend = 7.25; P < .01). Multivariate linear regression showed that bacteremia was associated with a prolongation of neonatal intensive care unit stay of 14.0 +/- 4.0 days (P < .01) and an increase in hospital charges of $25,090 +/- 12,051 (P < .05), even after adjustment for birth weight and admission-day SNAP.
Nosocomial coagulase-negative bacteremia is an important complication among very low birth weight infants. Assessment of illness severity with SNAP provides information regarding nosocomial infection risk beyond that available from birth weight alone.
在考虑出生体重和住院时间等传统风险决定因素后，研究入院时疾病严重程度对医院获得性菌血症风险的影响。
对连续入住两个新生儿重症监护病房的302例极低出生体重（小于1500克）婴儿的住院病程进行检查，以确定医院获得性凝固酶阴性葡萄球菌菌血症的发生情况。使用累积发病率和发病密度作为菌血症风险的衡量指标，我们探讨了疾病严重程度（通过新生儿急性生理学评分[SNAP]衡量）与出生体重调整前后菌血症之间的关系。此外，还估计了菌血症对医院资源利用的影响。
凝固酶阴性葡萄球菌是入院48小时或更晚采集的血培养中最常见的病原体。53例患者至少有一次分离到该菌（每100例患者累积发病率为17.5例首发）。这些发作发生在7652个危险日，发病密度为每1000个患者危险日6.9例初始菌血症。正如预期的那样，与非菌血症组相比，菌血症患者出生体重较低（888±231 vs 1127±258克；P<.01），胎龄较小（26.4±2.1 vs 28.9±2.8周；P<.01）。此外，这些患者入院时病情更严重（SNAP 17.3±6.5 vs 12.2±5.8；P<.01）。即使在按出生体重分层后，两种测量方法下菌血症的风险都随着SNAP评分的升高而增加。例如，在出生体重超过1千克的婴儿中，病情最严重的患者（SNAP 20及以上）中有25%经历了至少一次菌血症发作，而病情中等（SNAP 10至19）和病情较轻（SNAP 0至9）的婴儿的发生率分别为8.6%和3.0%（趋势χ2=7.25；P<.01）。多变量线性回归显示，即使在调整出生体重和入院日SNAP后，菌血症仍与新生儿重症监护病房住院时间延长14.0±4.0天（P<.01）和医院费用增加2,5090±12,051美元（P<.05）相关。
医院获得性凝固酶阴性菌血症是极低出生体重婴儿的重要并发症。用SNAP评估疾病严重程度可提供超出仅根据出生体重可得信息的医院感染风险信息。
