Biomedical subjects
M E Speer
Publications and source records attributed to M E Speer.
Neonatal intensive care applications of near-infrared spectroscopy.
Near-infrared spectroscopy (NIRS) is a noninvasive technique for assessing cerebral hemodynamic variables and oxidative status in the neonatal intensive care setting. It can be performed for extended periods of time at the bedside without interfering with routine patient care. NIRS appears to have the ability to not only assess relative changes in oxygenated and deoxygenated hemoglobin, total hemoglobin, and cytochrome aa3, but it can also produce estimates of cerebral blood volume and cerebral blood flow. Research data document significant changes in these hemodynamic variables with patient activity and clinical interventions in both premature and term infants. NIRS may evolve into an important diagnostic and prognostic tool for neonatal neurologic outcome.
Use and abuse of apnea monitors--1995. Position statement of the Texas Pediatric Society Committee on Fetus and Newborn.
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Use of hospital discharge packs--1995. Position statement of the Texas Pediatric Society Committee on Fetus and Newborn.
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Screening for illicit drugs in the newborn infant. Position statement of the Texas Pediatric Society Committee on Fetus and Newborn.
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Obstetrical risk management.
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Posttransfusion cytomegalovirus infection in neonates: role of saline-washed red blood cells.
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Early detection of bacteremia in an outpatient clinic.
A total of 570 patients, aged less than 24 months, who were seen in the emergency room at Texas Children's Hospital for evaluation of acute febrile illness had a WBC count, differential count, and a blood culture obtained. Bacteremia occurred in 7.7% (n = 44) (22 Haemophilus influenzae; 17 Streptococcus pneumoniae; three Escherichia coli; one group B Streptococcus; one Staphylococcus aureus). The sensitivity, specificity, and positive predictive value of morphologic changes (vacuolization and toxic granulation) of polymorphonuclear neutrophils (segmented neutrophils plus band cells), WBC count greater than or equal to 15,000/microL and band cells greater than or equal to 500/microL were examined. Additionally, abnormalities in three of four tests (WBC count greater than or equal to 15,000/microL, band cells greater than or equal to 500/microL, segmented neutrophils greater than or equal to 10,000/microL, and/or total polymorphonuclear neutrophils greater than or equal to 10,500/microL) were evaluated. Morphologic changes of polymorphonuclear neutrophils were noted frequently in patients with culture-proven bacteremia (63% and 51% positive predictive value for vacuolization and toxic granulation, respectively) and were more predictive of bacterial infection than traditional tests. If both vacuolization and toxic granulation were present, the positive predictive value increased to 76%. Examination of the peripheral blood smear may provide important adjunctive information for the presence of bacteremia prior to bacteriologic confirmation.
Fatal hepatoadrenal necrosis in the neonate associated with echovirus types 11 and 12 presenting as a surgical emergency.
Two neonates presented to our service with suspected intraabdominal surgical emergencies. Both subsequently were found to have hepatoadrenal necrosis due to overwhelming echoviral infection. Echovirus types 11 and 12 were isolated postmortem. The latter virus has not been associated previously with fulminant neonatal illness.
Use of deglycerolized red blood cells to prevent posttransfusion infection with cytomegalovirus in neonates.
In an effort to reduce the rate of posttransfusion infection with cytomegalovirus (CMV), 157 CMV-seronegative neonates were given deglycerolized red blood cells as their only source of red blood cells. Other blood products given to these patients received no special preparation. The 106 (67.5%) infants available for adequate evaluation received an average of 5.7 units (range, one to 39 units). Three hundred thirteen (51.4%) of the 609 transfused units were CMV-seropositive. When evaluated three months after their last transfusion, none of the 106 infants had virological or serological evidence of CMV infection. These results suggest that regardless of the serological status of the donor, deglycerolized red blood cells can reduce or possibly eliminate posttransfusion CMV infection and can serve as a safe alternative to CMV-seronegative blood. Freezing, depletion, and physical disruption of leukocytes may be responsible for the decreased infectivity of the deglycerolized product.
Elevation of plasma concentrations of arginine vasopressin following perinatal asphyxia.
Hypoxic ischemic encephalopathy is a major cause of mortality in neonates. Studies in experimental subjects have shown differing responses of plasma arginine vasopressin to hypoxia. Plasma arginine vasopressin levels, serum osmolality, urine osmolality and fluid intakes were measured in thirteen asphyxiated and nineteen control newborn infants during the first seventy-two hours of life. In the asphyxiated infants plasma arginine vasopressin was found to be elevated as compared to control infants on days one (p less than 0.001) and two (p less than 0.007) but not on day three of life. Urine osmolality was also elevated in the study patients on days one (p less than 0.01) and two (p less than 0.001) but not on day three, in spite of equal intakes of fluid on day one in both groups and significantly diminished fluid intake on days two and three in the study patients. Serum osmolality was not different between the two groups on any day studied, and was felt to be on the basis of diminished intake in the study infants. The data presented in this study support the concept that arginine vasopressin release occurs following perinatal asphyxia in term newborn infants.
Degenerative changes in neutrophils: an indicator of bacterial infection.
A review was made of 195 peripheral blood smears of 157 neonates who required sepsis work-up in the first month of life. Degenerative changes of neutrophils including vacuolization and toxic granulation were observed frequently in infants with culture-proven bacterial sepsis. Of 21 peripheral blood smears from 20 neonates subsequently proven to have bacterial infection, 17 had vacuolization present in the neutrophils for a sensitivity of 81%, a specificity of 93%, and a positive predictive accuracy of 59%. Toxic granulation changes in neutrophils showed similar results. This simple test can be performed easily in all hospitals; it does not require special laboratory facilities. The test appears to provide a valuable adjunct in the early detection of neonatal bacterial infection.
Intraventricular hemorrhage and vitamin E in the very low-birth-weight infant: evidence for efficacy of early intramuscular vitamin E administration.
To determine whether early intramuscular vitamin E supplementation influences the incidence of intraventricular hemorrhage (IVH) in infants with birth weight less than or equal to 1,500 g, data were analyzed from 134 infants enrolled on a protocol to evaluate the efficacy of intramuscular plus oral vitamin E v oral supplementation alone in the treatment of retrolental fibroplasia. All 134 infants received, via nasogastric tube, 100 mg/kg/d of vitamin E daily (dl-alpha-tocopheryl acetate in MCT [medium-chain triglyceride] oil; 150 mosM) for at least 8 weeks with the first dose administered within the first eight hours of life. Sixty-four patients received, in addition, intramuscular vitamin E on days 1, 2, 4, and 6 of life and 70 patients received placebo injections in a randomized double-blind fashion. In the first week, vitamin E plasma levels were significantly higher in the 64 patients given intramuscular vitamin E. In spite of this difference no change in the incidence of sepsis or necrotizing enterocolitis was observed. Both the incidence and severity of intraventricular hemorrhage were reduced significantly in the patients given intramuscular vitamin E as compared to the patients given placebo (P = .013 and P = .04, respectively). The data suggest that vitamin E, a natural antioxidant, may play an important role in protecting the CNS microcirculation from the effects of hypoxic/ischemic injury.
Retrolental fibroplasia and vitamin E in the preterm infant--comparison of oral versus intramuscular:oral administration.
To evaluate the efficacy of four early intramuscular injections of vitamin E given in addition to continuous minimal oral vitamin E supplementation, 168 very low-birth-weight infants (less than or equal to 1,500 g) have enrolled in a randomized, double-masked, clinical study. All infants received vitamin E orally, 100 mg/kg/d. In addition, on days 1, 2, 4, and 6, seventy-nine infants received vitamin E intramuscularly, 15, 10, 10, and 10 mg/kg, respectively. On the same days, 89 control infants received placebo intramuscular injections. Multivariate analysis of the 135 infants who survived greater than or equal to 10 weeks showed no significant difference in the development of severe retrolental fibroplasia between these two supplementation schedules (P = .86). Plasma vitamin E levels never exceeded a mean of 3.3 mg/100 mL, and no toxicity was observed. Ultrastructural analyses of seven pairs of whole eye donations from infants receiving IM vitamin E demonstrated identical kinetics of gap junction formation between adjacent spindle cells as compared with 13 pairs of whole eye donations from control infants (P greater than .3). Therefore, oral vitamin E supplementation affords retinal protection against the development of severe retrolental fibroplasia when initiated on the first day of life and maintained continuously until retinal vascularization is complete.
Effect of continuous heparin infusion on bactericidal activity for group B streptococci in neonatal sera.
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Creatine phosphokinase BB isoenzyme in very-low-birth-weight infants: relationship with mortality and intraventricular hemorrhage.
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Calcification of superficial scalp veins secondary to intravenous infusion of sodium bicarbonate and calcium chloride.
Soft tissue calcification has been reported following the intramuscular injection of calcium salts and the intravenous administration of calcium gluconate. The present case report describes a neonate in whom calcification of the superficial scalp veins developed following administration of calcium chloride and sodium bicarbonate through a scalp vein needle.
Retrolental fibroplasia: further clinical evidence and ultrastructural support for efficacy of vitamin E in the preterm infant.
To further evaluate the efficacy of oral vitamin E in preventing the development of severe retrolental fibroplasia (RLF) in very low-birth-weight infants, 100 infants treated with 100 mg/kg/d of vitamin E (dl-alpha-tocopheryl acetate) were compared with 75 infants treated with 5 mg/kg/d of vitamin E (dl-alpha-tocopherol) in the same nursery during the previous year. All 175 infants weighed less than or equal to 1,500 g at birth and required supplemental oxygen. A total of 120 infants (69 treatment; 51 control) survived greater than or equal to 10 weeks. Multivariate analysis of the control population identified five risk factors (P less than or equal to .10): gestational age, level and duration of oxygen administration, intraventricular hemorrhage, sepsis, and birth weight. When multivariate analysis was applied to both control and treatment groups, the severity of RLF was found to be significantly reduced in infants given the treatment dose of vitamin E (P = .003). Ultrastructural analyses of 58 pairs of whole-eye donations from high-risk infants surviving less than 10 weeks suggest that the initial morphologic event is gap junction increases between the plasma membranes of adjacent spindle cells of the van-guard retina. Such extensively gap junction-linked spindle cells are apparently removed from the vasoformative process as early as 4 days of life, forming a barrier to further normal vascular development and triggering retinal and vitreal neovascularizations approximately 8 weeks later. These events are maximally suppressed by elevated plasma vitamin E levels in infants greater than or equal to 27 weeks gestational age.