The influence of microhabitat on the population dynamics of four herbaceous species in a semiarid area of northeastern Brazil.

Variation in annual rainfall is considered the most important factor influencing population dynamics in dry environments. However, different factors may control population dynamics in different microhabitats. This study recognizes that microhabitat variation may attenuate the influence of climatic seasonality on the population dynamics of herbaceous species in dry forest (Caatinga) areas of Brazil. We evaluated the influence of three microhabitats (flat, rocky and riparian) on the population dynamics of four herbaceous species (Delilia biflora, Commelina obliqua, Phaseolus peduncularis and Euphorbia heterophylla) in a Caatinga (dry forest) fragment at the Experimental Station of the Agronomic Research Institute of Pernambuco in Brazil, over a period of three years. D. biflora, C. obliqua and P. peduncularis were found in all microhabitats, but they were present at low densities in the riparian microhabitat. There was no record of E. heterophylla in the riparian microhabitat. Population size, mortality rates and natality rates varied over time in each microhabitat. This study indicates that different establishment conditions influenced the population size and occurrence of the four species, and it confirms that microhabitat can attenuate the effect of drought stress on mortality during the dry season, but the strength of this attenuator role may vary with time and species.

Determinants of preterm delivery and intrauterine growth retardation in north-east Brazil.

A case-control study was conducted in Natal, north-east Brazil to determine the risk factors for low birthweight (LBW). Cases were 429 preterm and 422 intrauterine growth retarded (IUGR) singleton infants. Controls were 2555 infants of normal birthweight and gestational age. The prevalence of LBW was 10% (5.1% preterm and 4.9% IUGR). Logistic regression was used to estimate the adjusted odds ratios of LBW, and attributable risk per cent (AR%) was used to estimate the proportion of LBW that might be prevented. The preventable determinants of preterm delivery were births to women less than 20, (AR = 7.1%), low maternal weight less than 50 kg (AR = 20.5%), smoking during pregnancy (AR = 14.6%) and infrequent antenatal visits (AR = 28.1%). Other important determinants of preterm delivery were prior LBW births, gestational illness and vaginal bleeding. The main preventable causes of IUGR were low maternal weight (AR = 17.8%), low maternal education (AR = 11.6%), smoking (AR = 14.8%), and inadequate antenatal care (AR = 11.6%). Other risk factors for IUGR include primiparity, prior LBW births, and illness during gestation. In this population, the focus of short-term preventive programme should be improvement in maternal nutrition, cessation of smoking, reduction of births to women under 20, and improved antenatal care.

Levels and determinants of early neonatal mortality in Natal, northeastern Brazil: results of a surveillance and case-control study.

An institution-based surveillance and nested case-control study was conducted in Natal, Northeastern Brazil to estimate the level and determinants of early neonatal mortality. The early neonatal mortality rate was 25.5 per 1000 live-birth, 75% of early neonatal deaths were premature low birthweight infants, and the mortality rates were 591 and 318 per 1000 respectively, for preterm small for gestational age (PT-SGA) and preterm appropriate for gestational age (PT-AGA) infants. Mortality was 50 per 1000 for term low birthweight, and 8.6 for term normal birthweight AGA infants. In addition to prematurity and low birthweight, the main risk factors associated with early neonatal death were maternal smoking, complications during pregnancy or intrapartum, and inadequate antenatal care. The associations were weaker for prepregnancy factors such as single marital status or low maternal body weight, and no significant associations were observed with socioeconomic status. These findings suggest that in this population, efforts to reduce early neonatal death should focus on improved maternal care and the prevention of prematurity.

PIP: To facilitate health service planning, a surveillance and case-control study were conducted of births in 3 hospitals and 2 maternity clinics in the city of Natal in northeastern Brazil. The surveillance study revealed 285 early neonatal deaths among the 111,171 singleton live births recorded in the study institutions from September 1984-February 1986, for a rate of 25.5/1000. 75% of these early neonatal deaths involved premature infants. The mortality rates were 591/1000 for preterm small-for-gestational age infants and 318/1000 for preterm appropriate-for-gestational age infants, while this rate was 50/1000 for term low-birthweight infants and only 8.6/1000 for term normal birthweights infants. The case-control study indicated that the maternal risk factors of body weight under 50 kg and single parent status significantly increased the likelihood of early neonatal mortality, while maternal age, parity, prior reproductive loss, and socioeconomic status did not have a significant effect on this outcome. Pregnancy-related factors that substantially increased the risk of early neonatal death included smoking, bleeding during the first or second trimester, toxemia, less than 5 prenatal care visits, and congenital malformations. These pregnancy-related risks exerted a more substantial effect than maternal characteristics, suggesting the feasibility of a strategy focused on preventing preterm births through prenatal care rather than a high-risk approach of screening women prior to pregnancy.

Wound infection rates in clean surgery: a potentially misleading risk classification.

OBJECTIVES: To evaluate the incidence of wound infection in inguinal hernioplasties, incisional hernioplasties, splenectomies, and splenectomies performed in patients with hepatosplenic schistosomiasis, and to examine the relationship of surgical wound infection to antibiotic use, patient age, length of stay in the hospital prior to surgery, and the duration of the operation. DESIGN: Retrospective surveillance study. RESULTS: One thousand five hundred forty-two clean operations were analyzed. Comparing response (wound infection) and explanatory variables (age, length of hospital stay, duration of surgery, antibiotics, and surgery type), we found that age, use of antibiotics, and type of surgery were statistically significant, while length of hospital stay and duration of surgery were not significant. CONCLUSIONS: From these results, we can predict that the probability of wound infection in surgical patients considering these significant variables is lower for patients ages 14 to 30 years and higher for patients ages 31 to 60 years and lower for patients with prophylactic antibiotic use (up to 72 hours of use) and higher for patients with prolonged use (more than 72 hours); and lower for patients undergoing inguinal heria, followed in ascending order by nonschistosomotic patients undergoing splenectomy in schistosomotic patients.

Postdischarge surveillance for nosocomial wound infection: does judicious monitoring find cases?

From 1988 through 1992, we conducted a prospective study of postdischarge surgical wound infection surveillance in our institution. A total of 6604 patients were seen after discharge in a centralized outpatient clinic, supervised by the infection control commission. Wounds were inspected, stitches were removed, and dressings were changed. This care was followed by referral of patients to the appropriate specialized surgical clinic. Postdischarge patient return rates for the period studied ranged from 68.4% to 91.2%. Wound infection detection in the outpatient clinic ranged from 32.2% (20 patients in 1991) to 50% (44 patients in 1990) for general surgical procedures and 52.9% (18 patients in 1990) to 91.4% (32 patients in 1992) for cesarean sections. Most surgical wound infections (87.6%, 127 patients) were diagnosed between the first and fourteenth postoperative days. We conclude that centralized postdischarge surveillance, as practiced in our institution, has enhanced the retrieval of wound infection data. At present, there is no universally accepted strategy for monitoring postdischarge surgical wound infection; however, we must take a rigorous approach to detect patients at risk for infection in our continuous attempt to improve the quality of surgical and postoperative care.

Late results on the surgical treatment of Chagasic megaesophagus with the Thal-Hatafuku procedure.

BACKGROUND: Chagas' disease has a wide distribution in Central and South America. It is endemic in 21 countries, with 16 to 18 million persons infected and 100 million at risk. Surgical treatment of achalasia from Chagas' disease is the first choice in advanced stages. The aim of this study was to analyze the late clinical followup of 50 patients operated on for Chagas megaesophagus with the Thal-Harafuku procedure. STUDY DESIGN: During the period of January 1966 to January 1993, 50 patients suffering from advanced achalasia from Chagas' disease were submitted to the Thal-Hatafuku procedure. The patients answered a questionnaire concerning the most relevant postoperative symptoms. The Thal-Hatafuku procedure was performed as the first surgical option (46 patients), and on reoperations because of failure of other surgical techniques (4 patients). RESULTS: The mean followup was 63.11 months for the 44 patients with longterm followup. Postoperative complications included surgical site infection (3 of 50 patients), urinary infections (3 of 50 patients), atelectasis (2 of 50 patients), pleural effusion (2 of 50 patients), and deep venous thrombosis (1 of 50 patients). The main symptoms found in the postoperative period were dysphagia (20 of 44 patients), heartburn (11 of 44 patients), vomiting (13 of 44 patients), and retrosternal pain (6 of 44 patients). Eleven patients of the 44 remained asymptomatic at the end of the followup period. Outcomes were analyzed according to the modified Visick classification. Visick classes I and II represented 25% and 27.3%, respectively. Eighteen patients (40.9%) were classified as Visick III. CONCLUSION: We conclude that the Thal-Hatafuku operation is a therapeutic option that should be considered in the treatment of achalasia of the esophagus secondary to Chagas' disease, in advanced cases.

A case-control study of stillbirths in northeast Brazil.

An institution based case-control study to determine risk factors for stillbirths was conducted in the city of Natal, NE Brazil, where 90% of deliveries take place in health facilities. Two hundred thirty-four singleton stillborn cases were compared to 2555 liveborn singleton control infants of normal birth-weight and gestational age. Information was obtained by postnatal interview and anthropometry, and review of medical records. Univariate analyses revealed a large number of potential risk factors, but after adjustment by logistic regression only six factors remained significantly associated with stillbirth. These were low maternal weight, less than or equal to 50 kg and a history of pregnancy loss, both with odds ratios (OR) of 1.8, inadequate prenatal care defined as less than five visits (OR = 1.9), gestational complications (OR = 14.2), intrapartum complications (OR = 2.0), and congenital malformations (OR = 8.7). There was also an increased risk of stillbirth among older mothers who smoked (OR = 1.4), and evidence of an interaction between smoking and complications of pregnancy. From the public health perspective, the most important factors amenable to intervention were inadequate prenatal care and antenatal or intrapartum complications which were associated with substantial attributable risks (23.8%, 35.2%, and 10.2%, respectively). Thus, in this population, future reductions of the high stillbirth rate (27.2 per 1000 births) will largely depend on the coverage, utilization, and quality of antenatal and intrapartum care.

Ascorbic acid in schistosomiasis mansoni with or without digestive haemorrhage.

The authors studied the variations of ascorbic acid levels in white blood cells and plasma by Denson-Bowers' method in 20 normal individuals (Group I) and 36 schistosoma patients with hepatosplenic disease with and without gastrointestinal haemorrhage (Groups II and III, including 18 patients each). Having submitted the results to statistical analysis with a probability rate of 95%, the authors concluded that, while no significant difference could be seen between Groups I, II and III in ascorbic acid levels in white blood cells, there was a significant decrease in plasma ascorbic acid levels of Group III as compared with Groups I and II.

The control of postoperative infection in general surgery.

The results of a prospective study of infection control carried out in the Division of Abdominal Surgery of the Federal University of Pernambuco over a two year period are presented. A total of 760 patients operated on by the various teams of the Division were studied and rates of wound, respiratory and urinary infection were analyzed together with their relationship to the types of surgery performed. The etiology and antibiotic sensitivity of the main etiologic agents are also presented, plus a comparison of the results obtained with data found in the literature.

Advanced megaesophagus with recurrent dysphagia following initial surgical treatment.

The results of the surgical treatment of twenty patients with advanced megaesophagus who had undergone previous treatment are presented. After the previous operation, the asymptomatic period was less than five years in mot cases; symptoms included dysphagia (100%), regurgitation (65%), heartburn (50%), pain (45%), excess saliva (20%) and palpitations (10%). The definitive treatment was cervico-abdominal esophagectomy (45%), distal esophagectomy (20%), Thal-Hatafuku's operation (15%) and miscellaneous (15%). In our experience, the best procedures are cervico-abdominal esophagectomy and Thal-Hatafuku's operation.