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Biomedical subjects

S M Donn

Publications and source records attributed to S M Donn.

At least 37 records · Page 2Linked to original sources
PubMed1994

Splenic enlargement in neonates during ECMO.

PURPOSE: To determine whether hepatosplenomegaly was a reproducible finding in seven neonates who were being treated with extracorporeal membrane oxygenation (ECMO) for respiratory failure. MATERIALS AND METHODS: The authors measured splenic and hepatic dimensions with ultrasound (US) at the time ECMO was initiated and then every 24-48 hours until decannulation. Splenic volume and the index of hepatic size were calculated by using published formulas. RESULTS: Splenic volume increased in all seven patients from 8.3 cm3 +/- 1.7 to 16.4 cm3 +/- 4.4 (P < or = .001). Hepatic size did not change markedly. CONCLUSION: Hemolysis, leukopenia, and platelet activation occur during ECMO. Rapid splenic enlargement may be secondary to sequestration of red cells, platelets, and other hematologic elements that have been damaged in the ECMO circuit. Since the liver does not also increase in size, the splenic enlargement is unlikely to be the result of passive congestion.

Extracorporeal Membrane Oxygenation↗
PubMed1991

Multicenter controlled trial comparing high-frequency jet ventilation and conventional mechanical ventilation in newborn infants with pulmonary interstitial emphysema.

One hundred forty-four newborn infants with pulmonary interstitial emphysema were stratified by weight and severity of illness, and randomly assigned to receive treatment with high-frequency jet ventilation (HFJV) or rapid-rate conventional mechanical ventilation (CV) with short inspiratory time. If criteria for treatment failure were met, crossover to the alternate ventilatory mode was permitted. Overall, 45 (61%) of 74 infants met treatment success criteria with HFJV compared with 26 (37%) of 70 treated with CV (p less than 0.01). Eighty-four percent of patients who crossed over from CV to HFJV initially responded to the new treatment, and 45% ultimately met success criteria on HFJV. In contrast, only 9% of those who crossed over from HFJV to CV responded well to CV (p less than 0.01), and the same 9% ultimately met success criteria (p less than 0.05). Therapy with HFJV resulted in improved ventilation at lower peak and mean airway pressures, as well as more rapid radiographic improvement of pulmonary interstitial emphysema, in comparison with rapid-rate CV. Survival by original assignment was identical. When survival resulting from rescue by the alternate therapy in crossover patients was excluded, the survival rate was 64.9% for HFJV, compared with 47.1% for CV (p less than 0.05). The incidence of chronic lung disease, intraventricular hemorrhage, patent ductus arteriosus, airway obstruction, and new air leak was similar in both groups. We conclude that HFJV, as used in this study, is safe and is more effective than rapid-rate CV in the treatment of newborn infants with pulmonary interstitial emphysema.

Bronchopulmonary Dysplasia↗
PubMed1991

Hemodynamic instability after the initiation of extracorporeal membrane oxygenation: role of ionized calcium.

OBJECTIVES: To prospectively document the occurrence of ionized hypocalcemia in infants and children treated with extracorporeal membrane oxygenation (ECMO), to determine if the type of calcium salt (calcium chloride or gluconate) used in priming the ECMO circuit affected ionized calcium, to determine if ionized calcium concentrations correlate with total calcium, protein, albumin, or total magnesium values, and to determine if the hypotension usually observed after ECMO initiation correlates with low circulating ionized calcium concentrations. DESIGN: Prospective study. SETTING: Pediatric ICU and neonatal ICU. PATIENTS: Sixteen neonatal and three pediatric patients who were started on ECMO for cardiopulmonary support. INTERVENTIONS: The ECMO circuit was primed in a standardized manner, 100 mg of calcium gluconate was added in group 1 patients and 100 mg of calcium chloride was added in group 2 patients. MEASUREMENTS: Ionized calcium was measured from the circuit before initiation of ECMO and from the patient before, and then 5, 10, 15, 30, 60, 120, and 240 mins after initiation of ECMO. Total calcium and ionized calcium concentrations were measured simultaneously every 6 hrs. Serum total protein, albumin, magnesium, and ionized calcium values were measured from blood samples collected simultaneously twice daily. RESULTS: A significant decrease in the mean serum ionized calcium value occurred 5 mins after the initiation of ECMO in both groups, p less than .001. The ionized calcium value remained significantly decreased until 30 mins after the initiation of ECMO. There were no differences between the ionized calcium concentrations obtained during priming with calcium gluconate vs. those concentrations obtained with calcium chloride priming (p = .79). Throughout the course of ECMO, the serum ionized calcium concentrations ranged from 0.60 to 1.86 mmol/L. Poor correlations existed between circulating ionized calcium values and total calcium (r2 = .30), total protein (r2 = .20), albumin (r2 = .20), and magnesium concentrations (r2 = .10). There was a good correlation between the patients' BP and ionized calcium concentrations after bypass was initiated (r2 = .87). CONCLUSION: Our data demonstrate that ionized hypocalcemia is a frequent occurrence after the initiation of ECMO. Since there is a poor correlation between ionized calcium and total calcium, ionized calcium concentrations should be measured directly in these patients.

Blood Pressure↗
PubMed1991

Symptomatic subarachnoid hemorrhage in the term newborn.

A review of the medical records of 35 term newborn infants with confirmed subarachnoid hemorrhage was undertaken to examine etiologic, clinical, laboratory, and neurodevelopmental aspects of this lesion. The most common clinical presentation was convulsive activity (69%), followed by apnea (23%), and bradycardia. Thirty-one of these infants (89%) survived, but only 16 (52%) were felt to be neurologically normal at latest evaluation. Outcomes appeared to be similar regardless of whether the presumed etiology was hypoxic-ischemic or traumatic. Six surviving infants (19%) developed post-hemorrhagic hydrocephalus, but in three of these there was a delayed presentation well beyond the neonatal period. Symptomatic subarachnoid hemorrhage in the term newborn may be a more serious event than previously believed. Close neurodevelopmental follow-up and surveillance for hydrocephalus is warranted.

Brain Diseases↗
PubMed1990

ECMO indications and complications.

Widely adopted while prospective validation was still under way, extracorporeal membrane oxygenation is now a clinically established treatment for reversing neonatal respiratory failure. The technique's accomplishments are impressive-83% survival in conditions otherwise associated with 80% mortality-but its problems include significant handicap in 20% of treated survivors.

Extracorporeal Membrane Oxygenation↗
PubMed1990

Use of high-frequency jet ventilation in the management of congenital tracheoesophageal fistula associated with respiratory distress syndrome.

Two preterm infants (28 weeks, 960 g; 32 weeks, 1,870 g) with very large tracheoesophageal fistulas suffered from respiratory distress syndrome and failed to respond to conventional mechanical ventilation despite placement of a decompressive gastrostomy. Pulmonary air leaks developed in both, resulting in transdiaphragmatic pneumoperitoneum, and significant gas flow occurred through the gastrostomy tube despite placement under water-seal. High-frequency jet ventilation was instituted in each case and resulted in improved pulmonary gas exchange at lower mean airway pressure (12.0 to 6.7 cm H2O; 11.0 to 8.0 cm H2O) and in prompt resolution of air leaks. Both patients remained refractory to reinstitution of conventional ventilation until division of the fistula in the first patient and complete resolution of the respiratory distress syndrome in the second.

Female↗
PubMed1990

Tracheobronchial and pulmonary histopathology following conventional and high-frequency jet ventilation.

The advent of high-frequency jet ventilation (HFJV) as an alternative method of respiratory support for newborns has been implicated as a causative agent of necrotizing tracheobronchitis (NTB). We conducted a controlled trial of prolonged HFJV and conventional mechanical ventilation (CMV) in adult cats to determine effects on airway injury related to mode of ventilation and placement of the jet injector (proximal vs distal trachea). Fifteen cats were randomly assigned to either high-frequency positive pressure ventilation, proximal injection jet ventilation, or distal injection jet ventilation. The animals were ventilated for more than 33 hours. Post mortem, the trachea and respiratory tree were removed en bloc and fixed in formalin. A pathologist, unaware of the mode of ventilation, examined tracheobronchial histology and assigned scores using a technique previously described. Lung parenchymal tissue was also assessed using a similar grading system. Statistical analysis (Kruskal-Wallis analysis of variance) demonstrated no significant differences between tracheobronchial or lung parenchymal histopathology regardless of the mode of ventilation. We conclude that (1) the adult cat serves as a useful model for evaluating histopathologic effects of prolonged ventilation, (2) the etiology and pathogenesis of airway injury appears to be multifactorial, and the mode of ventilation is only one of many contributing variables, and (3) previously demonstrated differences between CMV and HFJV may be related to a much shorter duration of ventilation.

Animals↗
PubMed1989

The impact of gestational age on dysmaturity/postmaturity.

The medical records of 403 infants admitted to the neonatal intensive care unit were reviewed. All were postterm (greater than or equal to 42 weeks' gestation) infants or infants who were full term (greater than or equal to 38 weeks' gestation) and had clinical diagnoses associated with the neonatal postmaturity/dysmaturity syndrome. Data collected from these 403 records were used to generate frequency distribution tables for a variety of obstetric and neonatal outcome variables. Regression analyses were used to assess associations among these variables and the presence or absence of fetal malnutrition (dysmaturity) or postdatism. Fetal distress and neonatal acidosis were associated with both dysmaturity and postdatism. Primigravidas, meconium-stained amniotic fluid, cesarean section, birth trauma, and neonatal death were associated with postdatism but not with dysmaturity. Preeclampsia, maternal smoking, oligohydramnios, low Apgar score, neonatal pulmonary hypertension, neurologic abnormalities, and a need for extracorporeal membrane oxygenation were associated with dysmaturity. No interaction between postdatism and dysmaturity was seen for any outcome variable. Postdatism and dysmaturity appear to contribute risk factors independently to infants admitted to the intensive care unit.

Female↗
PubMed1988

Life span of intravenous cannulas in a neonatal intensive care unit.

Peripheral intravenous cannula use in a neonatal intensive care unit was surveyed prospectively to ascertain the rate of complications and the factors influencing the life span of an intravenous cannula. During a three-month period in which 199 intravenous cannulas were inserted in 69 patients, only two significant infiltrations (1%) were observed in more than 5000 hours of intravenous therapy. None of the factors studied, including weight, age, type and rate of fluid administration, and type of medication (except pancuronium bromide), had any discernible effect on the functional life span of intravenous cannulas. Pancuronium was associated with a significant prolongation of cannula life span--from 30 to 50 hours. We conclude that in this setting, the rate of clinically significant complications from intravenous cannula therapy is low.

Catheterization, Peripheral↗
PubMed1988

Neonatal hypoxic-ischemic encephalopathy: current management practices.

A national survey of training programs in neonatal-perinatal medicine was undertaken to determine neurologic management practices in dealing with the asphyxiated, term newborn. Seventy-two of 105 responses (68.6 per cent) were returned. Commonly used diagnostic tests include routine electroencephalography, cranial sonography, and determinations of arterial blood gases and serum calcium. Fluid restriction and treatment of seizures with phenobarbital are widely used therapies. Many available techniques for both diagnosis and treatment show wide variability in utilization. These results demonstrate a lack of a "standard" approach to the problem and suggest the need for well-designed clinical trials to assess efficacy and safety of treatment measures inconsistently applied to the asphyxiated, term newborn.

Academic Medical Centers↗
PubMed1988

Intraventricular hemorrhage in preterm twin gestation infants.

The incidence of intraventricular hemorrhage (IVH) in twin pregnancy infants with birthweights less than 1500 g in a 5 year period was examined retrospectively. Of the 70 infants in this birthweight category (for which IVH status was known) born at the University of Michigan Medical Center between January 1980 and December 1984, 20 had IVH (29%) (p = NS). The only significant association with IVH was respiratory distress. Presentation, route of delivery, a low 5 minute Apgar score, and time between first and second delivery were not significant factors. However, a multiple logistic regression of the infants categorized by IVH status demonstrated significant effects of twinship itself and of birth order within a given twinship. The unexpected low incidence of IVH in this high risk group suggests that better obstetric and neonatal management of low birthweight preterm twins at tertiary care centers may result in improved survival and decreased morbidity including intraventricular hemorrhage.

Birth Order↗
PubMed1988

Right-sided brain lesions in infants following extracorporeal membrane oxygenation.

In retrospective review of survivors of neonatal extracorporeal membrane oxygenation, eight patients with varying degrees of right hemispheric brain injury were identified. The extent of preextracorporeal membrane oxygenation hypoxia and ischemia was documented: five of eight patients had arterial PO2 values of less than 40 mm Hg, seven of eight required dopamine for blood pressure support, and five of eight required cardiopulmonary resuscitation. Two patients had proven neurologic abnormalities before extracorporeal membrane oxygenation. Postextracorporeal membrane oxygenation CT brain scans showed right hemispheric focal abnormalities in three patients. Seven infants had neuromotor abnormalities which were lateralizing in nature; all were left sided, suggesting right-sided brain injury. EEGs showed an increased incidence of slowing and attenuation over the right hemisphere. These findings indicate that right-sided brain abnormalities exist after extracorporeal membrane oxygenation and that carotid artery ligation for extracorporeal membrane oxygenation is not without risk.

Brain↗
PubMed1987

Intrapartum fetal heart rate patterns and neonatal intraventricular hemorrhage.

A goal for the obstetrician and neonatologist is to screen for risk factors associated with intraventricular hemorrhage (IVH) in the low-birthweight infant. Perinatal events that lead to neonatal metabolic and cardiovascular derangements seem to provoke IVH, and conflicting reports have implicated labor as being contributory. A fetal heart rate (FHR) abnormality during premature labor may be a predictor of subsequent neonatal IVH. For this reason, 5 years of FHR tracings at two university medical centers were reviewed for inborn infants who were delivered after premature labor and weighed less than or equal to 2000 gm. Sixty-four infants developed IVH, but pre-existing labor with a discernible FHR pattern was recorded in only 38 (59%) cases. Interpretations were reassuring in 17 (45%) cases, suspicious in 7 (18%) cases, and ominous in 14 (37%) cases. This proportion of FHR patterns was not significantly different from a matched group of premature infants without IVH during the same period. Interpretations of intrapartum FHR patterns of low-birthweight infants are limited, especially before 30 weeks gestation, and not useful in predicting neonatal IVH.

Adult↗