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Biomedical subjects

W D Engle

Publications and source records attributed to W D Engle.

24 records · Page 2Linked to original sources
PubMed1981

Effect of heat shielding on convective and evaporative heat losses and on radiant heat transfer in the premature infant.

Ten premature infants nursed on servocontrolled radiant warmer beds were studied in three environments designed to alter one or more factors affecting heat transfer (convection, evaporation, and radiation). In the control environment, infants were nursed supine on an open warmer bed. The second environment (walled chamber) was designed to reduce convection and evaporation by placing plastic walls circumferentially around the bed. In the third environment convection and evaporation were minimized by covering infants with a plastic blanket. Air turbulence, insensible water loss, and radiant warmer power were measured in each environment. There was a significant reduction in mean air velocity in the walled chamber and under the plastic blanket when compared to the control environment. A parallel decrease in insensible water loss occurred. In contrast, radiant power demand was the same for control and walled environments, but decreased significantly when infants were covered by the plastic blanket. This study suggests that convection is an important factor influencing evaporation in neonates nursed under radiant warmers. The thin plastic blanket was the most effective shield, significantly reducing radiant power demand.

Bedding and Linens↗
PubMed1981

The diuretic phase of respiratory distress syndrome and its relationship to oxygenation.

To determine the relationship between improvement in pulmonary function and diuresis in respiratory distress syndrome, ten consecutive premature infants requiring mechanical ventilation for severe RDS were studied. Every infant had a diuresis (output/intake greater than 80%), which began at 26 to 34 hours of life and which lasted for an additional 64-72 hours. The diuresis preceded significant improvement in AaDo2 and ventilator settings (IMV, PIP, PEEP) by 52 hours. There was a significant decrease in body weight among all study infants during the first four days of life despite an increase in fluid intake. This study suggests a relationship in RDS between improvement in oxygenation and removal of interstitial lung edema.

Body Weight↗
PubMed1981

Radiant warmer power and body size as determinants of insensible water loss in the critically ill neonate.

Twelve critically ill neonates mechanically ventilated for respiratory failure (mean weight 1.33 kg, mean gestation 31 wk) were studied to quantitate the effects of radiant power from a radiant warming device, body weight, and body surface area on insensible water loss. Radiant power density (Mw/cm2) was measured using a wattmeter and thermopile transducer. Insensible water loss was measured using a Potter Baby Scale. Weight correlated inversely with insensible water loss, (r = -0.86, P less than 0.001). Radiant power density correlated inversely to weight, (r = -0.71, P less than 0.001). There was a significant increase in insensible water loss as radiant power density increased, (r = 0.54, P less than 0.05). Net radiant power received (W/kg) by infants over their exposed surface area, correlated directly to insensible water loss, (r = 0.67, P less than 0.01) irrespective of body weight. Critically ill neonates ventilated for respiratory failure and nursed under radiant warmers incurred greater insensible water losses than previously reported for well infants. The magnitude of this increased insensible water loss is inversely related to body size and is determined directly by the radiant power density required to maintain body temperature.

Apnea↗
PubMed1980

Monitoring radiant power in the critically ill newborn under a radiant warmer.

To evaluate radiant power received by infants under radiant warmers, 11 neonates (mean gestational age 32.2 weeks, mean weight 1.50 kg) were monitored. A wattmeter was used to evaluate warmer power (watts), and a thermopile placed at bed level was used to correlate warmer power to radiant power density received (mw/cm2). Warmer power ranged from 133-301 watts. A linear relationship existed between warmer power and radiant power density received (r = 0.97, p < 0.001). After establishing that radiant power delivery could be monitored with a wattmeter, this technique was used to quantitate radiant power in a small series of infants with and without a plastic shield. Radiant power density received decreased in all infants when shielded (mean 14.6-11.2 mw/cm2, p < 0.01). This study demonstrates: (1) radiant warmer power can be monitored with a wattmeter; (2) warmer power correlates to radiant power density received; and (3) radiant power monitoring can be used to evaluate radiant power demands in specific clinical situations.

Apnea↗
PubMedDate not supplied

Neonatal pneumonia: comparison of 4 vs 7 days of antibiotic therapy in term and near-term infants.

OBJECTIVE: To compare a 4-day course of antibiotic therapy to a 7-day course in selected term and near-term neonates with pneumonia. METHODS: The diagnosis of pneumonia was made in neonates admitted to the normal Newborn Nursery (NBN) who later had signs of respiratory distress and whose chest radiographs were consistent with pneumonia. Infants were excluded if any of the following was present: moderate or thick meconium-stained amniotic fluid, prior antibiotic therapy > 24 hours, or need for supplemental oxygen > 8 hours. Infants who were asymptomatic after 48 hours of antibiotic therapy were prospectively randomized to a 4-day group (n = 35) or a 7-day group (n = 38). Infants in the 4-day group were observed in the hospital for 24 hours following cessation of antibiotics and were seen in follow up within several days of discharge. RESULTS: The groups were comparable with regard to demographic factors, duration of rupture of membranes, and incidence of maternal chorioamnionitis. Median postnatal age at the time of identification of respiratory distress symptomatology was 19 hours (range 0.5 to 55 hours) in the 4-day group and 12 hours (range 1 to 72 hours) in the 7-day group. No study infants had a positive blood culture. Mean reduction in length of hospitalization was 2.1 days, with estimated savings of greater than US$700 per shortened hospitalization. Two infants in the 4-day group developed tachypnea during the 24-hour observation period. However, no infants were rehospitalized for sepsis or pneumonia following discharge. With 95% confidence, the true rate of success for the 4-day group was at least 92%. CONCLUSION: Four days of antibiotic therapy plus a 24-hour period of observation for selected cases of neonatal pneumonia appears to be comparable to 7 days of therapy. It is important to note that newborns in our institution receive a single dose of penicillin soon after birth as part of our group B streptococcal sepsis prophylaxis program, and all infants in this study received prophylaxis prior to the onset of respiratory symptoms. Furthermore, only infants who were asymptomatic after 48 hours of antibiotic therapy were included in this study, and a 24-hour observation period at the end of the 4-day course was required. These qualifications should be taken into account before use of this approach is considered, and additional studies are necessary to further establish its safety and benefits.

Anti-Bacterial Agents↗