Background: Controversy exists as to the risk for postoperative apnea in former preterm infants. The conclusions of published studies are limited by the small number of patients.
Methods: The original data from eight prospective studies were subject to a combined analysis. Only patients having inguinal herniorrhaphy under general anesthesia were included; patients receiving caffeine, regional anesthesia, or undergoing other surgical procedures were excluded. A uniform definition for apnea was used for all patients. Eleven risk factors were examined: gestational age, postconceptual age, birth weight, history of respiratory distress syndrome, bronchopulmonary dysplasia, neonatal apnea, necrotizing enterocolitis, ongoing apnea, anemia, and use of opioids or nondepolarizing muscle relaxants.
Results: Two hundred fifty-five of 384 patients from eight studies at four institutions fulfilled study criteria. There was significant variation in apnea rates and the location of apnea (recovery room and postrecovery room) between institutions (P < 0.001). There was considerable variation in the duration and type of monitoring, definitions of apnea, and availability of historical information. The incidence of detected apnea was greater when continuous recording devices were used compared to standard impedance pneumography with alarms or nursing observations. Despite these limitations, it was determined that: (1) apnea was strongly and inversely related to both gestational age (P = 0.0005) and postconceptual age (P < 0.0001); (2) an associated risk factor was continuing apnea at home; (3) small-for-gestational-age infants seemed to be somewhat protected from apnea compared to appropriate- and large-for-gestational-age infants; (4) anemia was a significant risk factor, particularly for patients > 43 weeks' postconceptual age; (5) a relationship to apnea with history of necrotizing enterocolitis, neonatal apnea, respiratory distress syndrome, bronchopulmonary dysplasia, or operative use of opioids and/or muscle relaxants could not be demonstrated. 相似文献
Some 20 male New Zealand White rabbits (five/group) were given either didanosine (ddl) or stavudine (d4T) at 750 and 1500 mg/kg body weight/day by oral intubation for 24 wk. An additional group was given 300 mg/kg body weight/day zidovudine (AZT) as a negative control. After 13 weeks the high dose of ddl was lowered from 1500 to 1000 mg/kg body weight/day following the death of one rabbit and continued inappetence in the dose group. The rabbits were observed daily, plasma drug levels were monitored, and electrophysiological measurements of peripheral nerve conduction were performed during the study. Additionally, body weight and food intake were recorded, and clinicopathological parameters were evaluated. Sections of selected peripheral nerves, and dorsal and ventral spinal nerve roots were examined by light and transmission electron microscopy. Although peripheral neuropathy has been reported in rabbits with the nucleoside analogue zalcitabine (ddC), based on clinical observations, electrophysiological measurements, and light and electron microscopy, no evidence of peripheral neurotoxicity was observed in rabbits given either ddl or d4T. 相似文献
Here we demonstrate that perfused hearts removed from polyarthritic rats develop a pronounced coronary vasoconstriction ex vivo. This vasoconstriction is almost entirely blocked by in vivo pretreatment of the rats with the endothelin receptor antagonist, SB 209670. Thus, inflammatory states may be associated with an increased activity of the endothelin system, leading to vascular dysfunction and vasoconstriction. 相似文献
1. In vivo the effects of endothelin-1 (ET-1) are limited by its rapid removal from the circulation and possibly by its metabolism by enzymes such as neutral endopeptidase 24.11, deamidase or carboxypeptidase A. Here, using as a model the isolated perfused mesenteric arterial bed of the rat, we have examined the involvements of these enzymatic activities in the vascular responses to ET-1. 2. Samples of Krebs buffer which had been recirculated through the mesenteric arterial bed for 30 min rapidly destroyed the activity of ET-1 as assessed either by bioassay on rings of rat thoracic aorta or by high performance liquid chromatography (h.p.l.c.). For instance, after 15 min incubation with the recirculated-Krebs solution (recirc-K) the contraction induced by 3 x 10(-9) M ET-1 was reduced by more than 90%. Contractions induced by sarafotoxin 6b (3 x 10(-9) M) were similarly suppressed by preincubation with recirc-K whereas those to Arg-vasopressin (3 x 10(-9) M) were unaffected. 3. The degradation of ET-1 by recirc-K was prevented by 1,10-phenanthroline (10(-3) M), abolished by heating the recirc-K solution to 90 degrees C for 15 min, and reduced by EGTA (5 x 10(-3) M) or ET-1(16-21) (10(-5) M). For instance, in the presence of ET-1(16-21) (n = 6) the contraction induced by ET-1 was reduced by only 40% after 15 min incubation with recirc-K buffer.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
Estimates of the cost effectiveness and cost benefit of health promotion-health education methods for pregnant smokers designed to increase birth weight are not available. This paper presents the results of a cost-effectiveness analysis from a recently completed randomized trial to evaluate the effectiveness of self-help smoking cessation methods for pregnant women in public health maternity clinics. The study population--309 pregnant smokers from 3 prenatal clinics--were randomly assigned, during their first clinic visit, to 1 of 3 groups: (a) group 1 received the standard clinic information and advice to quit smoking, (b) group 2 received the standard clinic information and advice to quit plus the manual "Freedom From Smoking in 20 Days" by the American Lung Association, and (c) group 3 received the standard clinic information and advice to quit plus the pregnancy-specific manual "A Pregnant Woman''s Self-Help Guide to Quit Smoking." The quit rates by the end of pregnancy were 2 percent for group 1, 6 percent for group 2, and 14 percent for group 3. Analyses also indicated that the method used for group 3 was the most cost effective: group 3 achieved smoking cessation at less than half the cost experienced by the other two groups. Although additional studies are needed concerning the behavioral impact, cost effectiveness, and cost benefit of self-help health education methods for smoking cessation, the methods tested in this trial are promising as solutions to part of the problem of low birth weight among infants of smoking mothers in the United States. 相似文献
While previous studies have identified a protective effect for barbiturate anesthesia during focal cerebral ischemia, no such effect has been demonstrated for isoflurane. To better understand the effects of these anesthetics on cerebral blood flow and metabolism that might have relevance to their respective potential for cerebral protection, fasted physiologically stable rats underwent autoradiographic determination of CBF and CMRglu during deep isoflurane or pentobarbital anesthesia (burst suppression of EEG). As expected, cerebral blood flow was significantly greater during isoflurane anesthesia (isoflurane = 157 +/- 18 and pentobarbital = 54 +/- 12 ml/100 g/min) while CMRglu values were nearly identical (isoflurane = 35 +/- 5 and pentobarbital = 33 +/- 4 mumol/100 g/min). Additional identically anesthetized rats underwent middle cerebral artery occlusion with CBF autoradiographically determined 1 h later. While the insult resulted in a significant reduction in the ipsilateral hemispheric and cortical blood flow in both anesthetic groups, flow remained at least twofold greater in isoflurane as opposed to pentobarbital-anesthetized rats. When regional flow was assessed, no difference between groups was observed with respect to the area of tissue with flow values falling between 0-10 ml/100 g/min. In contrast, isoflurane-anesthetized rats had significantly less hemispheric and cortical area with flow values in the ranges of 10-20 and 20-30 ml/100 g/min, respectively. These data, therefore, do not support the contention that isoflurane causes maldistribution of CBF during focal ischemia. 相似文献