Search PubMed⌕ Search

Biomedical subjects

A R Spitzer

Publications and source records attributed to A R Spitzer.

At least 55 records · Page 3Linked to original sources
PubMed1995

No lumbar puncture in the evaluation for early neonatal sepsis: will meningitis be missed?

OBJECTIVE: We performed this investigation to assess whether selective approaches to performing lumbar puncture (LP) in the early neonatal period will result in a missed or delayed diagnosis of bacterial meningitis. DESIGN: A retrospective review was conducted of the medical records of all neonates born in US Army hospitals from 1988 through 1992 who developed culture-positive meningitis during the first 72 hours of life. RESULTS: In total, 169,849 infants were born during the 5-year study period. The incidence of meningitis in the first 72 hours of life was 0.25 per 1000 live births. Forty-three infants had organisms isolated from their cerebrospinal fluid (30, group B streptococcus; 10, Escherichia coli; 1, Listeria monocytogenes; 1, Streptococcus pneumoniae; and 1, Citrobacter diversus). The median age of infants at evaluation was 12 hours, and the mean gestational age was 38.8 weeks (7 < 37 weeks), whereas mean birth weight was 3163 g (7 < 2500 g). If we had used currently advocated selective criteria as the basis for not performing an LP, the diagnosis of bacterial meningitis would have been missed or delayed in 16 of 43 infants (37%): 5 infants born prematurely with suspected respiratory distress syndrome, 3 asymptomatic infants born at term with positive blood cultures, and 8 infants born at term with no central nervous system symptoms and negative blood cultures. CONCLUSIONS: If LPs are omitted as part of the early neonatal sepsis evaluation, the diagnosis of bacterial meningitis occasionally will be delayed or missed completely.

Diagnostic Errors↗
PubMed1995

Recent advances in home infant apnea monitoring.

Appropriate and effective nursing intervention is an essential element in determining how the family responds to the monitor in the home. Accurate assessment of the family system and dynamics provides the basis for a plan of care. The family's and infant's specific needs must be addressed. Careful implementation of the plan allows for changes and unexpected outcomes. Frequent evaluation of monitoring is necessary to determine if a change in the plan of care is needed. Recent changes in home apnea monitoring technology are rapidly altering the care of infants at risk for apnea and SIDS. The advent of the documented or recording monitor has the potential to demystify the events occurring while the infant is being monitored. Parents can get answers about their infant as quickly as a telephone call. The clinician can differentiate between a true and a false alarm and reassure the parents accordingly. Documenting false events and shallow-breathing alarms will potentially reduce the duration of monitoring, decreasing costs to the entire health care system. Documented monitoring is a valuable tool for nurses. For the staff nurse, clinical observation can be validated through trending and print out of events can be done at the bedside. For the advanced practice nurse, management of care can become more efficient through remote monitoring via modem. Patient teaching can be followed with immediate feedback. Monitors may assist in allaying anxiety in families who have lost children to SIDS or had an unexpected death in a previous sibling. Families may feel less anxious about having an "at risk" child in the home if the events are continuously being recorded. Length of hospital stay may decrease initially, with fewer rehospitalizations. Nursing research in these areas is necessary. Evaluating events occurring in the home may also help shed light on the enigma of SIDS. Several SIDS deaths have been recorded on documented monitors. If we can pinpoint exactly what takes place prior to and immediately after a SIDS episode, the enigma that has had physicians puzzled for so long may finally begin to unravel.

Apnea↗
PubMed1994

Risk factors for bronchopulmonary dysplasia after extracorporeal membrane oxygenation.

OBJECTIVE: To determine risk factors for the development of bronchopulmonary dysplasia (BPD) after treatment with extracorporeal membrane oxygenation (ECMO). DESIGN: Retrospective case-control study. SETTING: Tertiary care level 3 neonatal intensive care unit. PARTICIPANTS: Seventy-three newborns treated with ECMO for severe respiratory failure during a 5-year period, who survived until day of life 28, and who did not have pulmonary hypoplasia as the initial cause for respiratory failure. INTERVENTIONS: None. MAIN OUTCOME MEASURE: The presence of BPD after treatment with ECMO, which was defined as oxygen and/or ventilatory requirements at day of life 28, with characteristic abnormalities seen on chest x-ray film. RESULTS: The age at ECMO initiation was significantly greater for patients with BPD compared with patients without BPD (mean +/- SD, 135 +/- 68 hours vs 50 +/- 37 hours; P < .001). There was an 11.5-fold increased risk for the development of BPD if ECMO was initiated at greater than 96 hours of age. The primary diagnosis of respiratory distress syndrome imparted a 5.2-fold increased risk for the development of BPD. Patients with BPD required ECMO significantly longer than patients without BPD (203 +/- 73 hours vs 122 +/- 51 hours; P < .001). CONCLUSION: These results demonstrate that delayed use of ECMO in treating neonatal respiratory failure is associated with an increased risk for the development of BPD and a longer duration of ECMO therapy.

Age Factors↗
PubMed1994

High frequency jet ventilation: intraoperative application in infants.

The potential advantages of the intraoperative use of high frequency jet ventilation (HFJV) when compared with conventional ventilation (CV) include the maintenance of adequate gas exchange and lung function with a relatively motionless surgical field. To determine the pulmonary response to HFJV ventilation in infants during cardiac surgery, we evaluated lung function in nine infants supported with CV and HFJV during a Blalock-Taussig shunt procedure. Infants were randomized to each mode of ventilation with inspiratory and expiratory pressures and FiO2 held constant. Heart rate, blood pressure, arterial blood gases, pulmonary mechanics (lung compliance and resistance), and functional residual capacity (FRC) were compared after 10 minutes of stabilization of each ventilation mode, with the infants in the thoracotomy position and the surgical field adequately exposed. Pulmonary mechanics were measured using esophageal manometry and pneumotachography, and FRC by helium dilution. There was no difference in vital signs, pulmonary mechanics, FRC, or PaO2 on HFJV ventilation when compared with CV. Arterial PaCO2 was lower with a lower mean airway pressure on HFJV when compared with CV. The surgical team subjectively observed a diminished need for lung manipulation and improved ease of access to the surgical field with HFJV. These results indicate that the use of HFJV during closed-heart cardiac surgical procedures in infants provides similar cardiopulmonary stability and some potentially important clinical benefits when compared with CV.

Airway Resistance↗
PubMed1994

Right common carotid artery reconstruction after extracorporeal membrane oxygenation: vascular imaging, cerebral circulation, electroencephalographic, and neurodevelopmental correlates to recovery.

OBJECTIVE: Right common carotid artery (RCCA) ligation after extracorporeal membrane oxygenation by venoarterial bypass may contribute to lateralized cerebral injury. Reconstruction of this artery after extracorporeal membrane oxygenation has proved feasible but has not been evaluated for neurologic outcome in any substantial series of infants. METHODS: We evaluated RCCA reconstruction in 47 infants treated with ECMO and compared their cerebrovascular and neuroanatomic imaging findings, electroencephalograms, and developmental outcomes with those of 93 infants who had no reconstruction. SUMMARY RESULTS: Color Doppler blood flow imaging revealed that carotid artery patency was usually obtained after RCCA reconstruction. Right internal carotid and bilateral anterior and middle cerebral arterial blood flow velocities were generally higher, and were more symmetrically distributed in infants with reconstructed RCCA. Electroencephalography did not disclose an increased risk of deterioration or marked abnormalities in infants after reconstruction, nor were neuroimaging findings consistent with an increased number of either focal or generalized abnormalities. Neurodevelopmental follow-up revealed no differences in the incidence of delays between those with a reconstructed RCCA and those with a ligated RCCA during the first year of life. CONCLUSIONS: Reconstruction of the RCCA after extracorporeal membrane oxygenation may facilitate normal distribution of cerebral blood flow through the circle of Willis, and may augment both left and right middle cerebral artery blood flow immediately after decannulation. The long-term consequences of either ligation or reconstruction of the RCCA will require careful scrutiny, however, before either course is recommended routinely.

Blood Flow Velocity↗
PubMed1994

NNERVE: neural network extraction of repetitive vectors for electromyography--Part I: Algorithm.

Artificial neural network (ANN) based signal processing methods have been shown to have significant robustness in processing complex, degraded, noisy, and unstable signals. A novel approach to automated electromyogram (EMG) signal decomposition, using an ANN processing architecture, is presented in this paper. Due to the lack of a priori knowledge of motor unit action potential (MUAP) morphology, the EMG decomposition must be performed in an unsupervised manner. An ANN classifier, consisting of a multilayer perceptron neural network and employing a novel unsupervised training strategy, is proposed. The ANN learns repetitive appearances of MUAP waveforms from their suspected occurrences in a filtered EMG signal in an autoassociative learning task. The same training waveforms are fed into the trained ANN and the output of the ANN is fed back to its input, giving rise to a dynamic retrieval net classifier. For each waveform in the data, the network discovers a feature vector associated with that waveform. For each waveform, classification is achieved by comparing its feature vector with those of the other waveforms. Firing information of each MUAP is further used to refine the classification results of the ANN classifier. Then, individual MUAP waveform shapes are derived and their firing tables are created.

Algorithms↗
PubMed1994

NNERVE: neural network extraction of repetitive vectors for electromyography--Part II: Performance analysis.

We have presented a new method for the decomposition of clinical electromyographic signals, NNERVE, which utilizes a novel "pseudo-unsupervised" neural network approach to signal decomposition. In this paper, we present a detailed performance analysis. We present definitions for quantitative performance criteria. NNERVE is shown to be highly reliable over a wide range of neural network architectures. It is also minimally sensitive to learning parameters. The degradations of performance over a wide range of signals and parameters are shown to be gradual, slight and graceful. These characteristics are shown to translate directly into a high degree of robustness over widely varying signals. Real signals obtained from the entire range of patients encountered in clinical situations are shown to be correctly handled without any modifications or adjustments of any parameters. This neural network method is then directly compared to a prior traditional signal processing method and is shown quantitatively to have consistently superior performance on both simulated and real signals. Clinically acceptable performance over a wide range of signals, recorded using standard clinical methodology, and the lack of a need for user interaction, will facilitate the use of motor unit quantitation in routine clinical electromyography.

Algorithms↗
PubMed1994

Pulmonary function testing in the critically ill neonate, Part III: Case studies.

Accurate monitoring of respiratory status is of vital importance for the bedside nurse caring for the critically ill neonate. Pulmonary function testing can be utilized to effectively diagnose and quantitate lung disease in infants. Data obtained can be integrated into the nursing assessment and facilitate appropriate nursing interventions. The case studies provided in Part III of this series illustrate the utility of such testing in neonates with a range of illnesses and different diagnostic and therapeutic dilemmas. Case study one is an infant with chronic lung disease complicated by bronchospasm, case study two is an infant with bronchomalacia, and case study three demonstrates fine tuning of the ventilator in an infant with respiratory distress syndrome. Every study describes the usefulness of pulmonary function testing on a specific patient, each with different pulmonary pathology. These case studies, and the discussion in parts I and II of this series, illustrate the value of integrating pulmonary function data with ongoing clinical assessment to optimize the care of the sick or convalescing neonate. Tests ordered on a routine and/or as-needed basis will provide detailed information on the infant's pulmonary status that may be readily available at the infant's bedside. The neonatal nurse's involvement in requesting, performing, and interpreting these tests may enhance the treatment of the infant in intensive care.

Bronchial Spasm↗
PubMed1994

Pulmonary function testing in the critically ill neonate, Part I: An overview.

Respiratory insufficiency, a frequent problem encountered by the critically ill neonate, has many etiologies. Pulmonary function testing can effectively diagnose, quantify, and qualify the dysfunction so as to better define a prognosis and guide appropriate therapy. Recent advances in computer-assisted technology and miniaturization of equipment now allow simple, reproducible, and rapid neonatal pulmonary function assessment at the bedside. The indications for, and benefits of, pulmonary function testing vary with gestation, age, and clinical condition of the infant. The overall description of the pulmonary function profile is discussed in this article. The general questions and approaches utilized for routine testing, the initial pulmonary function profile, and evaluation of the acutely ill infant and that of the convalescing preterm are addressed. The expertise of the intensive care nurse is invaluable in ensuring that safe, accurate, and reproducible data are obtained. The nurse can then use the data to alter the infant's care plan and to determine the necessity and timing for retesting. Specific information on methodology and examples of specific tests are given in related articles (Parts II, Vol. 13 No. 2 and III, Vol. 13 No. 4, respectively). A complete knowledge of pulmonary function assessment is important for any nurse caring for critically ill neonates.

Humans↗
PubMed1994

Pulmonary function testing in the critically ill neonate, Part II: Methodology.

Pulmonary function testing is an important diagnostic tool in neonatal intensive care. These tests provide a detailed assessment of an infant's pulmonary status that can be used in several ways: to monitor the progression of lung disease, to streamline ventilator management, and to assess the infant's response to new treatments, such as surfactant replacement therapy or bronchodilators. In some settings, these tests are performed by specially trained nurses, and the results are available immediately for planning nursing care. This relatively noninvasive and low-risk assessment can be performed on all infants, whether on mechanical ventilation or breathing spontaneously. A comprehensive pulmonary function evaluation can be performed at the bedside in less than 60 minutes and is generally well tolerated. In this article, the determination of pulmonary "vital signs" tidal volume, minute ventilation, respiratory rate, pulmonary compliance, resistance, resistive work of breathing, and functional residual capacity-are discussed. The esophageal balloon technique for measuring dynamic pulmonary mechanics and energetics, as well as the helium dilution technique for measuring functional residual capacity, are described.

Education, Nursing, Continuing↗
PubMed1993

The clinical value of screening chest radiography in the neonate with lung disease.

To examine the role of routine chest radiography in the management of the critically ill neonate with pulmonary disease, 41 term and preterm infants with lung diseases were prospectively evaluated. Seventy radiographs (35%) were obtained for clinical indications and 128 (65%) for prospective screening. Studies were compared with each infant's most recent previous study, if available. Every exam was designated Level I, if the radiograph identified a new finding that required clinical intervention; Level II, if an abnormality or interval change was observed that did not require immediate intervention; or Level III, if there was no interval change since the previous radiograph. Thirty-three (47%) indication radiographs and 63 (49%) screening radiographs showed significant changes since the previous study. Twenty-four (34%) of the indication radiographs and 42 (33%) of the screening radiographs had Level I abnormalities (P = NS). Nine (13%) of the indication radiographs and 21 (16%) of the screening radiographs had Level II abnormalities (P = NS). Results suggest that routine screening chest radiographic studies are an important adjunct of care in critically ill newborns with respiratory disease and may identify potential problems before they are reflected in a change in clinical status.

Diagnostic Tests, Routine↗
PubMed1992

Electroencephalographic and behavioral-state studies in infants of cocaine-addicted mothers.

OBJECTIVE: To evaluate cerebral cortical function with electroencephalography in infants of cocaine-addicted mothers. DESIGN: Patient series. SETTING: The Children's Hospital of Philadelphia (Pa). PARTICIPANTS: Thirty-five consecutive infants of cocaine-addicted mothers hospitalized for a comprehensive health assessment and 51 healthy, age-matched infants studied with electroencephalography and respiratory thermistor because they were siblings of sudden infant death victims (comparison group). INTERVENTIONS: None. MEASUREMENTS/MAIN RESULTS: Behavioral states during spontaneous daytime sleep were classified as active sleep or quiet sleep; quiet sleep was further characterized as immature, tracé alternant sleep or mature, continuous, slow wave sleep. No episodes of ictal apnea or nonictal apnea were recorded in infants of cocaine-addicted mothers; nonictal apnea was observed in one control patient. No electrographic seizures were recorded. There were no significant differences between the proportions of infants exposed to cocaine in utero and that of controls who displayed excessive sharp electroencephalographic transients, background abnormalities, immaturity, and hypermaturity. Electroclinical sleep discordance was present in 5.7% of infants of cocaine-addicted mothers vs 0% of controls. Cocaine-exposed infants displayed mature, continuous, slow wave sleep below 45 weeks of conceptional age in a significantly higher percentage than those in the comparison group. CONCLUSIONS: Although frank electroencephalographic abnormalities were infrequent in infants whose mothers were addicted to cocaine, they differed significantly in their younger age of onset of continuous, slow wave sleep. Our findings provide continued reason for concern that infants of cocaine-addicted mothers may suffer subtle adverse neurologic, cognitive, or behavioral effects later in life. The longitudinal assessment of sleep disturbance and its relation to later development might permit tracking of the long-term effects of prenatal exposure to cocaine.

Child↗
PubMed1992

Neuromuscular causes of prolonged ventilator dependency.

We prospectively evaluated 21 patients with prolonged ventilator dependency, to determine the frequency of unsuspected neuromuscular disease as a cause of this condition, and to determine the types of such diseases. Assessment was performed with routine and specialized electrophysiologic procedures. None of the patients had known prior neuromuscular disease, and none had ongoing medical problems that could account for their continued ventilator dependency. Sixty-two percent were found to have a neuromuscular disease severe enough to account for the ventilator dependency. Most of the remaining cases had a contributory neuromuscular disease. In addition to critical illness polyneuropathy, several other significant categories were identified. Myopathic EMG changes were found in 50% of the subgroup assessed by quantitative EMG. We conclude that neuromuscular disease is the most important factor in prolonged ventilator dependency, and that diseases other than critical illness polyneuropathy represent an important cause of this syndrome.

Critical Care↗
PubMed1992

Prolonged apnea and oxyhemoglobin desaturation in asymptomatic premature infants.

Seventy-eight longitudinal four-channel recordings of heart rate, thoracic impedance, nasal thermistry, and pulse oximetry were performed on 26 asymptomatic premature infants (gestational age, 29.9 +/- 1.58 weeks; birth weight, 1,753 +/- 226 grams; postconceptional age, 34.3 +/- 2.0 weeks; postnatal age, 4.41 +/- 2.40 weeks; all values mean +/- SD). Tracings were scored for central and obstructive apnea, bradycardia, periodic breathing, apnea density, and prolonged apnea. The studies demonstrated 585 episodes (7.41/recording) of oxyhemoglobin desaturation with less than 90%. Recordings had a mean of 16.1 episodes of central apnea, 3.04 episodes of obstructive apnea, and 2.34 episodes of bradycardia. Periodic breathing and short obstructive apneas correlated significantly with the total number of oxyhemoglobin desaturations of less than 80% and 90%. Episodes of prolonged apnea were seen in 20 of 78 recordings. In the latter a significantly higher number of total desaturations (less than 90%), desaturations less than 80% and 90% in association with apnea and with bradycardia, longer desaturations, desaturations during sleep, and isolated bradycardia were observed. Variations in heart rate, thoracic impedance, nasal air flow, and pulse oximetry are associated with episodes of oxyhemoglobin desaturation in asymptomatic premature infants. These infants, although asymptomatic, may be at risk for impaired tissue oxygenation.

Apnea↗
PubMed1992

Total nodal radiation in progressive sarcoidosis. Case report.

The subject of this article is a patient with sarcoidosis with neurological involvement, who failed to respond to high dose steroid therapy and cyclophosphamide. Low doses (20 Gy) of total nodal and craniospinal irradiation resulted in an excellent response, the patient being alive and in good health 3 years after irradiation without any further steroid therapy.

Adult↗
PubMed1992

Quantitative computer analysis of the sounds of isolated motor unit action potentials.

To develop quantitative measures of motor unit action potential (MUAP) sounds, we correlated Fourier domain features of isolated, individual MUAPs with classic time domain measurements. There were moderate correlations between amplitude or duration measurements, and absolute low-frequency (39 to 234 Hz) energy and amplitude of the peak frequency, and high correlations between the composite time domain feature of amplitude x duration, and total energy, amplitude of the peak frequency, and absolute low-frequency energy. Polyphasic potentials have multiple peaks in the magnitude component of the Fourier transform. Phase information appears to convey the "crisp" sound of MUAPs close to the recording electrode. The clinical description of "large" or "small" MUAPs by sound is likely based on absolute low-frequency energy, and incorporates both amplitude and duration information. We conclude that features of isolated MUAPs may be analyzed in the Fourier domain, and that they correlate closely with traditionally used measures of known diagnostic significance. The sound of the EMG used by clinical electromyographers is amenable to quantitative analysis.

Action Potentials↗
PubMed1992

Mechanical ventilation in preterm infants: neurosonographic and developmental studies.

Surviving preterm infants of less than 34 weeks' gestation who were selected on the basis of serial cranial ultrasonographic findings during their nursery course had repeated neurologic and developmental examinations during late infancy and early childhood that established the presence (n = 46) or absence (n = 205) of spastic forms of cerebral palsy. Of the 205 infants without cerebral palsy, 22 scored abnormally low on standardized developmental testing during early childhood. The need for mechanical ventilation beginning on the first day of life (n = 92) was significantly related to gestational age, birth weight, Apgar scores, patent ductus arteriosus, grade III/IV intracranial hemorrhage, large periventricular cysts, and the development of cerebral palsy. In the 192 mechanically ventilated infants, vaginal bleeding during the third trimester, low Apgar scores, and maximally low PCO2 values during the first 3 days of life were significantly related to large periventricular cysts (n = 41) and cerebral palsy (n = 43), but not to developmental delay in the absence of cerebral palsy (n = 18). The severity of intracranial hemorrhage in mechanically ventilated infants was significantly associated with gestational age and maximally low measurements of PCO2 and pH, but not with Apgar scores or maximally low measurements of PO2. Logistic regression analyses controlling for possible confounding variables disclosed that PCO2 values of less than 17 mm Hg during the first 3 days of life in mechanically ventilated infants were associated with a significantly increased risk of moderate to severe periventricular echodensity, large periventricular cysts, grade III/IV intracranial hemorrhage, and cerebral palsy. Neurosonographic abnormalities were highly predictive of cerebral palsy independent of PCO2 measurements.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Diseases↗