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D L Stewart

Publications and source records attributed to D L Stewart.

At least 19 recordsLinked to original sources
PubMed2001

Early high-frequency oscillatory ventilation versus synchronized intermittent mandatory ventilation in very low birth weight infants: a pilot study of two ventilation protocols.

OBJECTIVE: To evaluate the feasibility of conducting a prospective, randomized trial comparing early high-frequency oscillatory ventilation (HFOV) to synchronized intermittent mandatory ventilation (SIMV) in very low birth weight (VLBW) premature infants. This pilot study evaluated two ventilator management protocols to determine how well they could be implemented in a multicenter clinical trial. Although this pilot study was not powered to detect differences in outcome, we also collected outcome data. DESIGN: Prospective, multicenter, randomized pilot study. SETTING: Seven tertiary-level intensive care nurseries with previous experience with both HFOV and flow-triggered SIMV. PATIENTS: Fifty infants weighing 501 to 1200 g, less than 4 hours of age, who had received one dose of surfactant and required ventilation with mean airway pressure > or =6 cm H2O and F(I)O2 > or =0.25, and had an anticipated duration of ventilation greater than 24 hours. INTERVENTIONS: Patients were stratified by birth weight and prenatal steroid status, then randomized to either HFOV or SIMV with tidal volume monitoring. Ventilator management for patients in both study arms was strictly governed by protocols that included optimizing lung inflation and blood gases, weaning strategies, and extubation criteria. MEASUREMENTS: Data were collected using the tools planned for the larger collaborative study. Protocol compliance was closely monitored, with successive changes in the protocol made as necessary to improve clarity and increase compliance. The incidence of major neonatal adverse outcomes was recorded. MAIN RESULTS: Data are presented for 24 HFOV and 24 SIMV infants (two infants, twins, were withdrawn from the study at parent's request). Nineteen of the 24 HFOV infants and 20 of the 24 SIMV infants survived to 36 weeks corrected age. Age at final extubation for survivors was 16+/-16 (mean+/-SD) days for HFOV infants and 24+/-24 days for SIMV infants. At 36 weeks corrected age, 14 of the 19 HFOV survivors were extubated and in room air, whereas 5 required supplemental oxygen. In comparison, 6 of the 20 SIMV survivors were extubated and in room air, whereas 14 required supplemental oxygen. Grade III/IV IVH and/or periventricular leukomalacia occurred in 2 HFOV and 2 SIMV patients. Overall compliance with the ventilator protocols was 82% for the SIMV protocol, and 88% for the HFOV protocol. CONCLUSIONS: The preliminary outcome data supports conducting the large randomized trial, which began in July of 1998. The protocols for the ventilator management of VLBW infants, both with HFOV and with SIMV were easily implemented and consistently followed, and are presented here.

Age Factors↗
PubMed2001

Predictors of acquiring a nosocomial bloodstream infection on extracorporeal membrane oxygenation.

PURPOSE: The aim of this study was to identify independent predictors of acquiring a nosocomial bloodstream infection (BSI) during extracorporeal membrane oxygenation (ECMO). METHODS: This retrospective cohort consisted of 202 neonates treated with ECMO from 1989 to 1998 at the author' institution. Data collected included patient demographics, primary and secondary diagnoses, white blood cell counts, antibiotic usage, presence of central lines, operative procedures, and outcome. Surveillance blood cultures were drawn daily from the circuit using sterile technique to identify acquired pathogens. Statistical analyses included logistic regression, Cox proportional regression analysis, and discriminate analysis. RESULTS: There were 1,245 blood cultures drawn on 202 patients (6.2 cultures per patient), and a nosocomial BSI was identified in 7 patients (3.4%) during this 10-year span. These were infections that were neither present nor incubating on admission. Pre-ECMO diagnoses of patients who had a nosocomial BSI while on bypass included group B beta-hemolytic streptococcal sepsis (n = 2), herpes simplex viral sepsis (n = 1), congenital diaphragmatic hernia (n = 2), persistent pulmonary hypertension (n = 1), and congenital heart disease (n = 1). The median time on ECMO before obtaining a positive culture was 390 hours. The infectious agents responsible for these BSIs included Staphylococcus epidermidis (n = 5), Staphylococcus aureus (n = 1), and Escherichia coli (n = 1). The major factor associated with acquiring a nosocomial BSI on ECMO was the duration of bypass (391 v 141 hours, P =.002). Additionally, patients in the BSI group were more likely to have had an arterial catheter in place (16 v 7 days, P =.009) and to have received more screening blood cultures (16 v 6 cultures, P < 001). White blood cell counts, absolute neutrophil counts, and immature/total (I/T) ratios were not useful in predicting a nosocomial BSI. Of the 31 patients who required ECMO for more than 10 days, 7 (23%) had a positive blood culture, and 5 of these 7 infants (71%) died (P =.03). CONCLUSIONS: The only predictor of acquiring a nosocomial BSI on ECMO was the duration of support for greater than 10 days. Because classical predictors of infection are unreliable while the patient is on ECMO, the authors suggest that obtaining daily surveillance blood cultures beginning on the tenth day should be performed with prolonged ECMO courses. The authors confirmed previous reports of the association between a prolonged ECMO course and a high mortality rate. However, the authors speculate that, in actuality, the primary diagnosis leads to the prolonged course of support and is the major factor in the infant' demise.

Antibiotic Prophylaxis↗
PubMed2001

Thyroid function in neonates with severe respiratory failure on extracorporeal membrane oxygenation.

The object was to study thyroid function in neonates with severe respiratory failure on extracorporeal membrane oxygenation (ECMO) and determine whether abnormal thyroid function correlates with prognosis. Total and free thyroxine (T4, FT4), total and free triiodothyronine (T3, FT3), reverse triiodothyronine (rT3), thyroid-stimulating hormone, and thyroxine binding globulin were measured in 14 newborn infants with severe respiratory failure (age 1-30 days) from samples collected before anesthesia for cannula placement, at 30, 60, and 360 min after initiation of ECMO, and on days 2, 4, 6, and 8. The patients were divided into survivors and non-survivors for statistical analyses. No differences were noted between survivors and non-survivors in the pre-ECMO mean serum concentrations of the thyroid function tests analyzed. In nine survivors, mean serum T4, FT4, T3, FT3, and rT3 all declined significantly within 30-60 min after initiation of ECMO, compared to baseline values. The values for all mean serum concentrations recovered completely and exceeded baseline between days 2 and 8. In five non-survivors, the decline of all mean serum values was not statistically significant and recovery to baseline was not achieved. The ratios of mean serum concentration of rT3/FT3 were significantly different between survivors and non-survivors across all times during the ECMO course (p < 0.0005). These findings indicate that abnormalities in thyroid function occur in neonates with severe respiratory failure on ECMO and that the rT3/FT3 ratio correlates with prognosis over the ECMO course. Survival was associated with a significant reduction of serum thyroid hormone concentrations followed by recovery. We speculate that, in neonates with respiratory failure on ECMO, adaptive mechanisms which enhance survival include the capacity to down-regulate the pituitary-thyroid axis.

Extracorporeal Membrane Oxygenation↗
PubMed2001

Vermont Oxford Network: effective and efficient medical care for the neonate.

The Vermont Oxford Network is a non-profit, voluntary collaboration of health care professionals supported by membership fees and research grants which collects data from 310 intensive care units located in the United States and in many countries around the world. Data are collected on infants between 401-1500 grams and this data is entered into an international database. The information generated by the Vermont Oxford Network can be used for comparisons among hospitals providing similar levels of care. Medical problems can be identified and quality improvement projects implemented. This network also provides an opportunity to participate in randomized clinical trials, serves as an educational tool for the hospital staff, and the information provided helps the physician practice evidence based medicine in an efficient manner. Currently four hospitals in Kentucky are participating in this network and the University of Louisville Hospital has participated in two controlled, randomized studies.

Clinical Trials as Topic↗
PubMed2000

Universal newborn hearing screening with automated auditory brainstem response: a multisite investigation.

OBJECTIVE: The purpose of the study was to assess the feasibility of performing universal newborn hearing screening in different clinical settings and tracking the infants who did not pass initial screening through their confirmatory testing. STUDY DESIGN: Between December 1996 and December 1997, a total of 11,711 infants were enrolled from five clinically different study sites. Universal newborn hearing screening was performed using automated auditory brainstem response (AABR) testing. Infants who did not pass the initial screening were tested again prior to discharge. Data regarding the rate of referral for follow-up testing, age of infant at screening, the duration of time required for screening, and type of personnel performing the test were collected. Formal audiology appointments were made prior to discharge for infants who required follow-up testing, and letters were sent with phone calls made to those who failed to keep their appointments for repeat testing. Outpatient testing consisted of a repeat AABR and, if necessary, a diagnostic auditory brainstem-evoked response, otoacoustic emission testing, and tympanometry. RESULTS: At the time of hospital discharge, the refer rate was < 2% (215 of 11,711 newborns) using AABR screening. Sensorineural hearing loss (SNHL) was confirmed in 32 of these infants, resulting in an overall incidence of confirmed SNHL of 2.7 per thousand newborns. The false-positive rate ranged from 0.3% to 2.5%, with a cumulative false-positive rate of 0.9% (1.5% if all infants lost to follow-up are included as false-positives). No false-negatives were identified. The average time of testing was 7.1 minutes independent of the personnel performing the testing and the age of testing was < 24 hours in 70% of the infants tested. The total number of infants lost to follow-up was 61 (29% of patients referred or 0.5% of the study population). CONCLUSION: This study demonstrated that the refer rate for universal hearing screening with the AABR was acceptably low when performed by a variety of personnel in typical nursery settings within the first 24 hours after birth. A low rate of screening failures with the AABR minimizes costs associated with subsequent follow-up assessments and lessens any potential impact of false-positive screening on the parent-newborn relationship.

Audiology↗
PubMed2000

Invasive Candida enteritis of the newborn.

Three premature infants (<800 g) showed invasive Candida at the site of their intestinal perforations. This entity is distinct from Candida peritonitis complicating necrotizing enterocolitis and was uniformly fatal. Recognition and aggressive antifungal therapy may improve outcomes.

Amphotericin B↗
PubMed1999

The Baltimore Alliance for the Prevention and Control of Hypertension and Diabetes: a model for developing a colorectal cancer community outreach program.

Many diseases that account for the majority of morbidity and mortality in African Americans are also associated with racial disparity. Such diseases include cardiovascular disease, diabetes, hypertension, cancer, acquired immunodeficiency syndrome, and violent injuries. Epidemiologic associations find the excess burden for these diseases to be rooted in biological, psychosocial, and socioeconomic factors. Community-based efforts often function in isolation, attempting to have impact on diseases that affect local residents; unfortunately, such programs cannot be comprehensive in their approach. Foreseeable gaps allow morbidity and mortality to continue to exist. The Baltimore Alliance for the Prevention and Control of Hypertension and Diabetes (the Alliance), based at the University of Maryland School of Medicine, provides an infrastructure where successful community-based programs that target hypertension and diabetes join together in collaborative effort. The Alliance creates an association that supports community-based efforts, helping improve the efficiency and efficacy of such programs. Such associations can help close gaps, enabling programs to have a more comprehensive impact on communities.

Black or African American↗
PubMed1998

Prevention and control of hypertension and diabetes in an underserved population through community outreach and disease management: a plan of action.

Hypertension and diabetes are overrepresented in the African-American population and can be particularly devastating in this population. These diseases share genetic predisposition, medical risk factors, and environmental influences as etiologic factors, and they may be interrelated, at least in part, by obesity and accompanying hyperinsulinemia. Noncompliance with treatment plans is a significant barrier to health improvement in both diseases, but increased attention to patient involvement in care is a potential solution to this long-standing problem. The Baltimore Alliance for the Prevention and Control of Hypertension and Diabetes was established in January 1998 to promote care to the underserved community of West Baltimore, Maryland, and to improve outcomes of hypertension and diabetes. Based at the University of Maryland School of Medicine, the Baltimore Alliance comprises a community health worker program, a church-based education and screening effort, managed care and pharmaceutical company (Hoechst Marion Roussel) partners, a health policy and services research group, and inpatient/outpatient clinical care sites in the health system. Mobilization, cultural relevance, and partnership are employed to ensure that the Alliance's goals of increased patient enrollment and retention in treatment programs will be achieved. Thereby, improved outcomes--clinical, humanistic, and economic--will result. Novel as well as classic approaches to patient education, compliance, and goal achievement are being pursued. Complete expert systems for hypertension and diabetes disease management are being created and will be implemented in the near future. Baseline practices and current outcomes are being identified to act as historical controls. The organization and administration of the Alliance will serve as a prototype that others may follow.

Academic Medical Centers↗
PubMed1998

The relationship between health status and blood pressure in urban African Americans.

African Americans have higher rates of hypertension and poorer health status than their white counterparts. This study assessed the relationship between health status, cardiovascular risk factors, and measured blood pressure. Free blood pressure screenings were performed at businesses and organizations located in west Baltimore. All individuals with cardiovascular risk factors were offered health education. Also, participants with a measured blood pressure of > or = 140/90 mm Hg were referred for free medical treatment. Participants completed a questionnaire that included demographics, cardiovascular risk factors, the Medical Outcomes Study SF 36, and two tests on cholesterol and heart disease knowledge. A total of 1389 African-American men and women were screened; 20% were found to have high normal blood pressure and 31% had stage 1 hypertension or higher. Those with hypertension reported lower physical functioning and poorer general health than those without high blood pressure. When compared with US normative data, participants reported higher levels in vitality and physical and emotional role functioning, more bodily pain, and poorer general health, but they were similar in physical functioning, social functioning, and mental health. Preliminary data suggest that hypertension does have an effect on health function.

Adult↗
PubMed1997

Retaining extracorporeal membrane oxygenation cannulae after extracorporeal support in the neonate: is it safe?

The retention of extracorporeal membrane oxygenation (ECMO) cannulae of ECMO is discontinued was originally developed to avoid reexploration of the neck in patients who may require a second course of ECMO. Because of the incidence, at the authors' institution, of thrombi noted on the ends of retained cannulae and their potential to cause significant morbidity, a critical review of this procedure was initiated. A telephone survey of 72 Extracorporeal Life Support Organization (ELSO) centers was conducted, and ELSO registry forms were requested for patients who had their cannulae retained. Twenty-four of these centers had performed the procedure of retaining ECMO cannulae. There were 324 neonatal and pediatric patients who had their cannulae retained, with 41 patients (12%) requiring a second course of ECMO and 17 of 41 (41%) surviving the second course. Twelve of the 24 ELSO centers that retain cannulae have reported complications. Analyses of the patients who had their cannulae retained showed that the three best predictors for requiring a second course of ECMO were the diagnosis of congenital diaphragmatic hernia (CDH) a high oxygenation index just before the initiation of ECMO, and a lengthy first ECMO course. The only difference between the survivors and nonsurvivors of the second course of ECMO was the length of the first ECMO course (P < .05). Five of the 25 patients who required two courses of ECMO had serious complications from their retained cannulae and all were nonsurvivors. The authors conclude that patients with retained ECMO cannulae are at high risk for developing thrombi, which can lead to severe embolic events. Therefore, the procedure of retaining cannulae should only be used in patients at high risk for requiring a second course of ECMO and not for the convenience of surgical availability to remove the cannulae.

Catheters, Indwelling↗
PubMed1997

Survival of patients with congenital diaphragmatic hernia during the ECMO era: an 11-year experience.

BACKGROUND/PURPOSE: Congenital diaphragmatic hernia (CDH) is associated with significant mortality and morbidity. To evaluate the impact of extracorporeal membrane oxygenation (ECMO) on survival, a review of our experience with CDH patients was initiated. METHODS: The authors performed a retrospective nonrandomized analysis of 98 consecutive CDH patients who were ECMO candidates, and were symptomatic within the first day of life, and underwent repair between May 1985 and May 1996. The patients were divided into three groups: Group 1 (n = 38) refers to patients who were clinically stable and underwent repair before 48 hours of age and did not need ECMO rescue; Group 2 (n = 29) consists of patients who underwent repair but required ECMO rescue; and Group 3 (n = 31) refers to patients who met ECMO criteria preoperatively and required ECMO for stabilization and later underwent repair on ECMO. The Kaplan-Meier survival graph was used for survival analysis. RESULTS: During the 11-year span, the overall survival rate of all CDH patients was 72% (71 of 98). The survival rate of patients who did not require ECMO support was 92% (35 of 38), whereas patients who required ECMO after repair had a 72% (21 of 29) survival rate. These were compared with a 48% (15 of 31) survival rate for those undergoing repair on ECMO. The differences in survival among the three groups were statistically significant using the log-rank test (P = .0018). CONCLUSIONS: Survival was significantly better for infants who underwent successful repair without ECMO than those who required ECMO rescue pre- or postrepair. The overall improved survival of CDH patients to 72% compared with historical controls of 38% to 58% may be attributed to ECMO, but the requirement of ECMO before repair, as well as the presence of congenital anomalies (P < .01), prematurity (P < .01), the need for a Gore-Tex patch at repair (P < .05), prenatal diagnosis at less than 25 weeks' gestation (P < .01), and the occurrence of an intracranial hemorrhage (P < .01), decreases the chances of survival.

Extracorporeal Membrane Oxygenation↗
PubMed1997

The use of extracorporeal membrane oxygenation in patients with gram-negative or viral sepsis.

To evaluate the use of extracorporeal membrane oxygenation (ECMO) in patients with Gram-negative or viral sepsis, a survey of ECMO centres comprising the Extracorporeal Life Support Organization was conducted. Data collected from neonatal and paediatric intensive care units included patient demographics, indicators of infection, presence of cardiac instability and respiratory criteria for ECMO. One-hundred-and-seven patients with documented sepsis were divided into survivors and nonsurvivors. Prior to ECMO, the patients with a persistent metabolic acidosis (p < 0.008) and/or hypotension requiring more than two inotropic agents (p < 0.02) to support blood pressure were less likely to survive. Also, patients with Gram-positive infections (77%) were more likely to survive their ECMO course than those with Gram-negative (60%) or viral infections (40%). Although survival is less in septic infants than in infants with traditional respiratory failure placed on ECMO, sepsis should not be a contraindication to the use of ECMO. The parents should be informed of the chances of survival with each type of sepsis or respiratory infection (if known), so that a truly informed decision can be made by the parents. We feel that the additional information regarding Gram-negative and viral sepsis should assist the clinician in this goal.

Acidosis↗