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Biomedical subjects

A R Spitzer

Publications and source records attributed to A R Spitzer.

At least 73 records · Page 4Linked to original sources
PubMed1992

Brain SPECT in neonates following extracorporeal membrane oxygenation: evaluation of technique and preliminary results.

Extracorporeal membrane oxygenation (ECMO) is a life-saving procedure in neonates with refractory respiratory failure that has been used at our institution since 1985. In an attempt to study its clinical value, regional cerebral blood flow (rCBF) alterations were measured using SPECT and 99mTc-HMPAO in 13 newborns following ECMO. Eight infants were studied after ECMO with reanastomosis of the right common carotid artery (RCCA), two with the permanent ligation of the RCCA, and three after veno-venous ECMO. Brain SPECT was technically satisfactory in all newborns using a triple-head SPECT system. Altered rCBF was found in 7 of 13 infants. In five newborns, there was a decrease in rCBF within the ipsilateral hemisphere, and in one infant, contralateral hemisphere was involved. In one infant, there was bilateral hemispheric involvement. The infant underwent cardiopulmonary resuscitation prior to ECMO and exhibited clinical features of hypoxicischemic encephalopathy at the time of SPECT. Only 2 of 13 newborns demonstrated morphologic changes on neuroimaging modalities such as cranial ultrasonography, computed tomography and magnetic resonance imaging. Our study demonstrates that: (1) functional brain imaging is feasible in neonates after ECMO; (2) SPECT has potential for demonstrating rCBF deficits not detectable by neuroanatomic imaging modalities; and (3) SPECT has potential clinical value in long-term follow-up of neurodevelopmental outcome after ECMO.

Brain↗
PubMed1992

Home monitoring.

This article addresses the controversies surrounding home monitoring for the treatment of infant apnea and in the prevention of sudden infant death syndrome. A program for the use of monitoring is outlined for the practicing physician, and the benefits and deficiencies of home cardiorespiratory recording are discussed.

Hemodynamics↗
PubMed1992

Diagnosis-related criteria in the consideration of extracorporeal membrane oxygenation in neonates previously treated with high-frequency jet ventilation.

High-frequency jet ventilation (HFJV) is one of several high-frequency techniques that are particularly valuable for treating the neonate with lung disease refractory to conventional ventilation or with pulmonary air leak. Extracorporeal membrane oxygenation (ECMO) has also emerged as a valuable rescue therapy for neonates of more than 2000 g birth weight and 34 weeks' gestation with intractable respiratory failure. With the concurrent introduction of HFJV and ECMO, the authors sought to evaluate the role of HFJV prior to the institution of ECMO therapy. The data base for 2856 neonates receiving mechanical ventilation in one unit was used to identify 73 (of 298 total) neonates treated with HFJV, who were eligible by age and weight criteria for ECMO. Patients were grouped by diagnosis, and the oxygenation index (OI) was calculated during therapy. Outcome was evaluated for mortality, and the sensitivity of the OI for predicting mortality was calculated. Neonates who survived with HFJV alone presented with an OI of 0.30 +/- 0.03 (SEM), significantly less than nonsurvivors (0.42 +/- 0.04, P = .016). Survivors responded to HFJV with a rapid decrease in OI at 1 hour (0.19 +/- 0.02, P less than .001) and 6 hours (0.15 +/- 0.01, P less than .001). Nonsurvivors did not respond significantly at 1 hour (OI = 0.33 +/- 0.04, P = not significant [NS]) or at 6 hours (OI = 0.40 +/- 0.06, P = NS). By diagnosis, neonates with respiratory distress syndrome survived more often with HFJV (28/34, 82%) than neonates with meconium aspiration (10/26, 38%) or diaphragmatic hernia (3/9, 33%). Neonates with respiratory distress syndrome seldom presented with high OI values, but the majority of those who did survived (5/7 survived with initial OI greater than or equal to 0.40).(ABSTRACT TRUNCATED AT 250 WORDS)

Birth Weight↗
PubMed1991

Pneumograms in premature infants: a study of longitudinal data.

In order to define longitudinal data in premature infants, impedance pneumograms were performed weekly on 23 healthy premature infants. Studies were performed while infants remained hospitalized and at the discretion of the attending physician following discharge. A total of 97 studies were obtained on the study group. The recordings were analyzed for percentage of sleep time spent in periodic breathing, apnea density, and duration of longest apneic pause. Infants in this study demonstrated decreased percent of periodic breathing and decreased apnea density with increased maturation; longest pause per recording was independent of postconceptional age. Results from this study provide data to assist in the evaluation of pneumograms in the premature infant.

Gestational Age↗
PubMed1991

Pseudoreflux syndrome-increased periodic breathing during the neonatal period presenting as feeding-related difficulties.

Sixteen infants who presented with symptoms suggestive of gastroesophageal reflux (GER)-associated apnea were evaluated at the Breathing Disorder Center of the Children's Hospital of Philadelphia. These neonates had a history of occasional emesis and an apparent life-threatening event (ALTE) that occurred while awake which was similar to the presentation of a group of infants previously described. Evaluation of the present group of infants however, revealed increased periodic breathing (12.1 +/- 1.8 SEM% of total sleep time) as opposed to the obstructive apnea that was typically seen with GER. Pathologic gastroesophageal reflux could not be diagnosed in relationship to apneic events. Infants who present during the first month of life with symptoms suggestive of GER-associated apnea should have careful evaluation of reflux and respiratory patterns to confirm the correct diagnosis. Because of the similarities of these infants to the GER group, we have called their disorder pseudoreflux.

Diagnosis, Differential↗
PubMed1991

Pulmonary mechanics in preterm neonates with respiratory failure treated with high-frequency oscillatory ventilation compared with conventional mechanical ventilation.

Pulmonary mechanics were measured in 43 preterm neonates (mean +/- SD values of birth weight 1.2 +/- 0.3 kg, gestational age 30 +/- 2 weeks) with respiratory failure who were concurrently randomly assigned to receive conventional mechanical ventilation (n = 22) or high-frequency ventilation (n = 21). The incidence of bronchopulmonary dysplasia was comparable in the two groups (high-frequency ventilation 57%, conventional ventilation 50%). Pulmonary functions were determined at 0.5, 1.0, 2.0, and 4.0 weeks postnatal ages. Data were collected while subjects were in a nonsedated state during spontaneous breathing. These sequential data show similar patterns of change in pulmonary mechanics during high-frequency ventilation and conventional mechanical ventilation irrespective of gestational age, birth weight stratification, or bronchopulmonary dysplasia. There was no significant difference in the pulmonary functions with either mode of ventilation during the acute phase (less than or equal to 4 weeks) of respiratory disease. When evaluated by the clinical diagnosis of bronchopulmonary dysplasia, the pulmonary data suggested a less severe dysfunction in the high-frequency oscillatory ventilation-treated bronchopulmonary dysplasia group compared with the conventional mechanical ventilation-treated group. These results indicate that high-frequency oscillatory ventilation in preterm neonates does not reduce the risk of acute lung injury; however, the magnitude of the pulmonary dysfunction in the first 2 weeks of life merits a reevaluation.

Bronchopulmonary Dysplasia↗
PubMed1989

Changes in pulmonary mechanics following caffeine administration in infants with bronchopulmonary dysplasia.

The effects of caffeine upon pulmonary mechanics were measured in 16 infants with bronchopulmonary dysplasia (BPD). Pulmonary function tests were performed immediately prior to and 1 hour following a dose of 10 mg/kg of caffeine. A 37% increase in minute ventilation (mean +/- SEM; 436.6 +/- 26.3 to 580.8 +/- 30.7 ml/min/kg) was seen with caffeine administration (P less than 0.001), primarily from a 42% increase in tidal volume (6.2 +/- 0.4 to 8.5 +/- 0.4 ml/kg) (P less than 0.001). Total lung resistance decreased by 20% (134.6 + 24.2 to 105.3 +/- 20.1 cmH2O/L/sec) (P = 0.01), and total pulmonary compliance improved by 47% (0.642 +/- 0.104 to 0.908 +/- 0.190 ml/cmH2O/kg) (P less than 0.01). In five matched control infants with BPD, no effects of placebo upon pulmonary mechanics were detected. Since caffeine has a wide therapeutic index with few side effects, it may be an effective adjunct in the treatment of infants with BPD.

Airway Resistance↗
PubMed1989

Ventilatory response to combined high frequency jet ventilation and conventional mechanical ventilation for the rescue treatment of severe neonatal lung disease.

High frequency jet ventilation (HFJV) was used to treat 176 infants who were either failing to respond to conventional mechanical ventilation (CMV) or demonstrating pulmonary air leak. The median birthweight for infants treated with HFJV was 1530 g, median gestational age was 31 weeks. Median duration of therapy with HFJV was 3.0, with a range of 0.1 to 27 days. During the first 24 hours of treatment, mean airway pressure decreased from 16.2 +/- 0.3 (Mean +/- SEM) cmH2O to 12.2 +/- 0.3 cmH2O, while mean PaO2 increased from 65.3 +/- 3.0 torr to 93.3 +/- 3.0 torr during the same time period. Simultaneously, mean PaCO2 decreased from 46.4 +/- 1.5 torr to 36.6 +/- 1.0 torr, although peak inflating pressure decreased from 34.3 +/- 0.7 cmH2O to 30.1 +/- 0.8 cmH2O. Ninety-five (54%) infants treated with HFJV survived. Of 123 infants with RDS 75 (61%) survived. The rate of complications for HFJV patients was similar to that seen with CMV in our nursery. This study suggests that HFJV provides improved oxygenation and ventilation of infants at lower mean and peak pressures compared to conventional mechanical ventilation. HFJV combined with CMV may be a valuable adjunct to therapy in infants with severe lung disease.

Acute Disease↗
PubMed1989

A method for determining optimal interelectrode spacing for cerebral topographic mapping.

Inappropriately large interelectrode spacing may result in significant errors of localization and erroneous measurements of amplitudes, due to aliasing. Oversampling with very large numbers of scalp electrodes is impractical. We present a generally applicable method for determination of optimal interelectrode spacing. This optimal spacing is computed from the Nyquist distance for the potential of interest. For most potentials, the bandwidth of the topographic distribution is not known, so it must be first measured by oversampling with tightly spaced electrode arrays. The Nyquist distance will vary for different types of cerebral potentials, different components of a given potential, and for different areas of the scalp. We have determined the Nyquist distances for interelectrode spacing necessary to record accurately the geographically small components of the SEP in the region of the sensory strip. These distances are less than 3 cm, which is significantly smaller than the 7 cm distance of the 10-20 system. Recordings of SEPs in this region made with larger spacings may have significant errors. Recordings made at the Nyquist distance may be precisely interpolated to arbitrary accuracy.

Brain Mapping↗
PubMed1988

Predicting survival in infants with persistent pulmonary hypertension of the newborn.

Since persistent pulmonary hypertension of the newborn (PPHN) often occurs as a life-threatening illness, it would be advantageous to identify the highest-risk infants within the first 24 hours of life so that transfer to centers with extracorporeal membrane oxygenation (ECMO) or high-frequency ventilation can be facilitated. Fifty-three infants with PPHN were evaluated retrospectively. A multivariate discriminant analysis of risk factors determined that lowest pH, critical PaCO2, highest inspiratory pressure (PI), maximum ventilator rate, and 5-minute Apgar score were significantly different between the 35 survivors (66%) and the 18 infants (34%) who had died when examined within the first 24 hours of life. A clinical scoring system was designed based on these five criteria, which predicted outcome accurately in 93% of infants. A logistic regression analysis was performed as a check on these results and found that lowest pH, critical PaCO2, and PI predicted outcome with great accuracy. These results suggest that the use of these scoring systems within the first 24 hours of age may help predict outcome in infants with PPHN.

Apgar Score↗
PubMed1988

Pulmonary hypertension and persistent fetal circulation in the newborn.

Despite these infants' very significant medical instabilities, which require vigorous therapeutic intervention, we have seen a population of infants with little in the way of persistent residual problems. Although many of their pulmonary complications persist after hospital discharge, most resolve within the first year of life. In addition, there are few neurodevelopmental disabilities encountered in such a high-risk population of children.

Epoprostenol↗
PubMed1987

Response of human-immunodeficiency-virus-associated neurological disease to 3'-azido-3'-deoxythymidine.

Four patients with human-immuno-deficiency-virus-associated neurological disease were treated with 3'-azido-3'-deoxythymidine (AZT). Three (two with chronic dementia, and one with chronic dementia and peripheral neuropathy) improved as assessed by clinical examination, psychometric tests, nerve conduction studies, and/or positron emission tomography; there was no improvement in the fourth patient who presented with paraplegia. These results support the hypothesis that certain AIDS-virus-associated neurological abnormalities are reversible by antiretroviral chemotherapy.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Postoperative apnea in preterm infants.

Preterm infants may become apneic during the immediate post-operative period. To define this risk, the authors studied prospectively the breathing patterns of 47 preterm infants less than 60 weeks postconception with pneumocardiograms before and after general inhalational anesthesia. Eighteen infants (37%) had prolonged apnea (greater than 15 s) postoperatively, and an additional seven infants (14%) had short apnea (6-15 s) postoperatively. An infant's risk of prolonged and short postoperative apnea was related to a young postconceptional age (P less than 0.05) and to a history of necrotizing enterocolitis (P less than 0.01). Furthermore, as the postconceptional age of the infant increased, the risk of postoperative apnea decreased proportionately (P less than 0.025). Among the 18 infants with prolonged apnea, 83% experienced multiple apneic episodes. Manual stimulation was required in order for breathing to return in 13 (72%) of the infants. Breathing resumed spontaneously in four (22%) of the infants, and one infant required mechanical ventilation due to repeated prolonged apnea. The first apneic event occurred within 2 h postoperatively in 13 of the infants (72%); the remaining five infants (28%) had their initial apneic episode as late as 12 h after operation. The postoperative time to the last prolonged apneic event was inversely related to the postconceptional age (P less than 0.01, r = -0.70) and extended up to 48 h postoperatively. The preoperative pneumocardiogram was not a reliable test for predicting postoperative apnea (sensitivity 56%, specificity 83%).(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Inhalation↗
PubMed1986

Infant apnea.

This review provides an understanding of current problems related to apnea of infancy. Methods for diagnosis, evaluation, and treatment of apnea are discussed.

Airway Obstruction↗
PubMed1986

Effect of gestational age upon prealbumin and retinol binding protein in preterm and term infants.

The relationships between maternal and umbilical cord levels of prealbumin and retinol binding protein (RBP) were studied in 68 mothers and in their appropriate-for-gestational-age neonates delivered between 25 and 42 weeks gestation. Arterial and venous concentrations of prealbumin and RBP in cord sera were also studied in a subsample of eight infants. In cord sera, prealbumin and RBP levels increased with gestational age (prealbumin, r = 0.47; RBP, r = 0.40, p less than 0.01), and were significantly different in neonates born at term compared to those born prematurely (mean +/- SD, prealbumin 12.0 +/- 3.9 mg/dl vs. 8.8 +/- 2.3 mg/dl, p less than 0.001; RBP, 2.3 +/- 0.8 vs. 1.8 +/- 0.5 mg/dl, p less than 0.005). No significant differences between arterial and venous concentrations of prealbumin and RBP were observed in cord blood. In maternal blood, serum prealbumin and RBP concentrations did not increase with length of gestation (25-42 weeks). Maternal prealbumin was not correlated significantly with infants' cord serum levels; the correlation coefficient for RBP was 0.29, p less than 0.05. Maternal prealbumin and RBP serum levels were approximately twice the values seen in neonates born both at term and prematurely. Although the difference between premature and full-term cord levels of prealbumin and RBP may reflect an increase in hepatic protein synthesis that occurs with maturation of the fetus and/or a change in placental function after 37 weeks gestation, neither of these factors sufficiently explains the variance in neonatal prealbumin and RBP levels.

Female↗