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Biomedical subjects

M S Gaylord

Publications and source records attributed to M S Gaylord.

10 recordsLinked to original sources
PubMed1996

Altered platelet-activating factor levels and acetylhydrolase activities are associated with increasing severity of bronchopulmonary dysplasia.

Lipid inflammatory mediators are thought to play an important role in the pathogenesis of neonatal lung injury and bronchopulmonary dysplasia (BPD). Because preliminary studies from the intensive care nursery of the University of Tennessee Medical Center, Knoxville, revealed linear increased in blood platelet-activating factor (PAF) levels in very low birthweight infants developing chronic lung disease and lower cord blood PAF acetylhydrolase activities in premature infants, it was theorized that altered platelet-activating factor levels and PAF acetylhydrolase activities are associated with increasing severity of BPD. Platelet-activating factor levels (blood and tracheal lavage) and PAF acetylhydrolase activities (blood and tracheal lavage) were measured over days 1 to 2, 3 to 5 and 6 to 7 in 16 ventilated infants and weekly in 9 infants with bronchopulmonary dysplasia. Platelet-activating factor values were normalized per nanogram of lavage blood urea nitrogen. Severity of bronchopulmonary dysplasia was estimated using the scoring system developed by Toce. Mean blood and lavage PAF levels and PAF acetylhydrolase activities were compared in infants developing bronchopulmonary dysplasia with those without the disease over the first seven days of life. Infants developing chronic lung disease were significantly smaller and of younger gestational age. In infants with bronchopulmonary dysplasia, higher PAF levels in blood were seen on days 3 to 5, along with increased lavage acetylhydrolase activities on days 1 to 2. Increased levels of PAF in lavage on days 3 to 5 were associated with increasing severity of bronchopulmonary dysplasia. Altered blood and lavage platelet-activating factor levels and PAF acetylhydrolase activities appear to be associated with the pathogenesis and severity of bronchopulmonary dysplasia.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1994

Suicide in the Hong Kong subway.

Between 1979 and 1991, 56 suicides occurred within the Hong Kong subway system. Data on these fatalities, together with data on those who survived suicide attempts, are presented, along with guidelines established to assist the subway system staff in detecting, preventing and coping with such acts of self-destruction.

Adult↗
PubMed1991

A successful decade of regionalized perinatal care in Tennessee: the neonatal experience.

We hypothesized that successful implementation of regionalized perinatal care would result in early identification and antenatal referral of high-risk neonates, and also improved stabilization before and during transport of those transferred postnatally. We conducted a retrospective study of demographic characteristics and transport outcome in two defined groups of neonates transported to regional perinatal centers in Tennessee, one group (n = 218) from the first year of regionalization (1975), and a second group (n = 261) from the 12th year (1986). The percentage of outborn infants decreased, from 50% of all admissions in 1975 to 22% in 1986 (P = .005). Likewise, the percentage of low-birthweight neonates transported after birth decreased, from 59% of all transports to 32% (P = .002). The frequency of stabilization measures performed before and during transport increased between study years (intravenous line placement: 12% to 58%, P = .0001; assisted ventilation: 10% to 33%, P = .001). The incidence of complications during transport decreased between study years (cyanosis: 25% to 8%, P = .0001; hypothermia: 30% to 3%, P = .0001; acidemia: 33% to 13%, P = .011). Both transport-related mortality and neonatal mortality decreased between study years (2.8% to 0.8%, P = .043; 17% to 7%, P = .0001, respectively). We conclude that regionalization during its first decade has been successful in improving perinatal care in Tennessee as indicated by favorable changes in referral patterns and improved outcome of transported neonates.

Humans↗
PubMed1991

Release of benzalkonium chloride from a heparin-bonded umbilical catheter with resultant factitious hypernatremia and hyperkalemia.

Elevated serum sodium and potassium levels were recently observed when sampled through a heparin-bonded umbilical catheter and measured with certain ion-selective electrodes. The cationic surfactant, benzalkonium chloride (BZC), is known to falsely elevate those cations in serum. Inasmuch as most heparin-bonded umbilical catheters use BZC during the bonding process, an in vitro study was performed to estimate the quantity of BZC released and the duration of sodium and potassium elevations during pooled sera infusion. Three heparin-bonded umbilical catheters and 3 silastic umbilical catheters were first flushed with 0.3 mL of normal saline and then perfused with pooled sera (sodium, 142 mEq/L; potassium, 4.6 mEq/L) at 2.5 microL/h. Effluent samples were collected from 0 to 8 hours and analyzed by ion-selective electrodes. Elevated serum sodium concentrations from 160 to greater than or equal to 250 mEq/L and potassium concentrations from 6.0 to greater than or equal to 9.6 mEq/L were observed. The BZC concentration in the catheter effluent was measured by mass spectrometry, with peak values of 10 micrograms/mL detected by this method. When varying concentrations of BZC (1 to 100 micrograms/mL) were added directly to pooled serum, a dose-dependent increase in serum sodium was observed. These data demonstrate that BZC released from heparin-bonded umbilical catheters elevates serum electrolyte values measured with some ion-selective electrodes. The observed increase in sodium and potassium concentrations may lead to clinical errors in management. Benzalkonium chloride is associated with myriad of linical symptomatology. Whether this amount of BZC is toxic in the small premature neonate is presently unknown.

Benzalkonium Compounds↗
PubMed1990

Predicting neonatal morbidity after perinatal asphyxia: a scoring system.

Predicting immediate neonatal morbidity after perinatal asphyxia has been difficult. A review of asphyxiated neonates greater than or equal to 36 weeks' gestation admitted to The Children's Hospital Newborn Intensive Care Unit in 1983 was conducted to devise a scoring system that would rapidly predict organ dysfunction observed in the immediate neonatal period. Comparison of potential score components to morbidity by multiple regression analysis yielded significant association with abnormalities in fetal heart rate monitoring, the 5-minute Apgar score, and neonatal base deficit. A scoring system was devised whose sensitivity (93.8%) and specificity (81.3%) were more predictive than any of its individual components. Prospective analysis in a similar population in 1984 validated its ability to distinguish severe from moderate morbidity after asphyxia. Positive predictive value for the score in the combined study groups (n = 98) was 79% and the negative predictive value was 83%. The scoring system may offer a rapid and accurate prediction of organ dysfunction in the immediate neonatal period after asphyxia.

Asphyxia Neonatorum↗
PubMed1987

High-frequency ventilation in the treatment of infants weighing less than 1,500 grams with pulmonary interstitial emphysema: a pilot study.

Pulmonary interstitial emphysema is one of the most serious complications of the respiratory distress syndrome. Its presence significantly increases morbidity and mortality. Preliminary reports have demonstrated the success of high-frequency ventilation in the treatment of pulmonary interstitial emphysema. In a previous investigation, we were able to develop a formula for predicting death in infants weighing less than 1,500 g with pulmonary interstitial emphysema. Using this subgroup of severely affected infants, we studied the efficacy of high-frequency ventilation in nine infants. Using the Volumetric Diffusive Respirator, we observed improvement in all respiratory values measured (pH, PCO2, and PO2), a significantly decreased mean airway pressure (MAP), and improvement in neonatal mortality. Complications of severe bleeding diatheses, hypotension, bronchopulmonary dysplasia, and necrotizing tracheobronchitis were observed. Our investigation was the first to systematically choose infants who might benefit from high-frequency ventilation and to compare them with similar infants with known outcomes. We realize that the study was rescue in nature using historical controls, but we felt compelled to assure the safety of the device before randomizing less sick infants. High-frequency ventilation appears to be effective in the acute management of low birth weight infants with pulmonary interstitial emphysema.

Humans↗
PubMed1985

Predicting mortality in low-birth-weight infants with pulmonary interstitial emphysema.

Due to the high mortality associated with pulmonary interstitial emphysema in the low-birth-weight infant, a method was developed to predict the infants most at risk for death. This information will allow the discriminant selection of patients for future trials of an alternative method of mechanical ventilation, high-frequency ventilation. During a 3-year-period (July 1, 1979 through June 30, 1982), 70 infants were retrospectively analyzed to determine the clinical parameters important in predicting mortality. The infants at highest risk for death included those of younger gestational age, those with birth weight less than 1,500 g (95% of all mortalities), and those that developed pulmonary interstitial emphysema within the first 24 hours of life. Mortality sharply increased in the infants with birth weight less than 1,500 g whose ventilatory requirements exceeded a peak inspiratory pressure of 25 cm H2O on day 1. Morbidity was high in the survivors as evidenced by a 54% incidence of bronchopulmonary dysplasia. With multivariant analysis, it was possible to isolate the variables (birth weight and highest peak inspiratory pressure on day 1) most influential in predicting mortality and to construct a formula for predicting mortality in the infants with birth weight less than 1,500 g. With a subsequent prospective study of 30 infants, the predictive accuracy of the formula was established.

Birth Weight↗
PubMedDate not supplied

Improved fluid management utilizing humidified incubators in extremely low birth weight infants.

OBJECTIVE: To compare fluid and electrolyte management in extremely low birth weight (ELBW) infants nursed in humidified versus nonhumidified incubators. STUDY DESIGN: Setting--tertiary intensive care nursery. Subjects--all infants with birth weight < 1000 g admitted 1/95 to 1/99 who were treated with incubators and survived for > 96 hours (N = 155). Intervention--retrospective comparison of daily weights, fluid intakes, urine outputs, and serum electrolytes between group 1 (n = 70, nonhumidified incubators, born 1/95 to 1/97) and group 2 (n = 85, humidified incubators, born 1/97 to 1/99) over the first 4 days after birth. RESULTS: Despite similar daily weight losses between groups, group 1 infants received higher fluid intakes, had lower urine outputs, and had a higher incidence of hypernatremia, hyperkalemia, and azotemia (p < 0.05). Although no differences in mortality or the incidence of patent ductus arteriosus, bronchopulmonary dysplasia, or the overall rate of nosocomial infections were observed, the proportion of gram-negative isolates increased significantly (62%, p < 0.05) following the introduction of humidified incubators. CONCLUSIONS: ELBW weight infants nursed in humidified incubators have lower fluid requirements, improved electrolyte balance, and higher urine outputs during the first 4 days after birth compared to those nursed in nonhumidified incubators.

Bronchopulmonary Dysplasia↗
PubMedDate not supplied

Evaluation of a portable insulin infusion pump for outpatient management of brittle diabetes.

Three "brittle" diabetic patients were given constant subcutaneous insulin infusion with a portable battery-driven pump, and their plasma glucose and hemoglobin A1 were measured at frequent intervals during inpatient or outpatient periods. Mean plasma glucose decreased significantly in all inhospital patients and remained significantly less than before pump therapy in two of three as outpatients during the 8--12 wk of follow-ups; however, complete normalization of glucose metabolism was not accomplished in any. All three demonstrated a progressive decline in hemoglobin A1 levels to normal or near-normal values. The need for long-term studies of open loop infusion systems in a research setting before their adaptation to routine care is emphasized.

Adolescent↗