Dale C. Alverson

Noninvasive pulsed Doppler determination of cardiac output in neonates and children

Mean blood flow velocity (VAo) in the ascending aorta was measured noninvasively in 33 children, ages 3 days to 17 years, by pulsed Doppler technique at the time of cardiac catheterization. Measurements were made from a suprasternal approach with a portable, range-gated device. The ascending aortic diameter was determined echocardiographically and aortic cross sectional area calculated (A = pi d2/4 cm2). Aortic flow (QAo) was computed from Doppler recordings: QAo (ml/minute) = VAo (cm/second) X A (cm2) X 60 (second/minute). Values were compared with cardiac outputs determined according to the Fick principle, using measured oxygen consumption calculated oxygen capacity, and oxygen saturation. Subjects with aortic valve abnormalities or left ventricular outflow tract obstruction were excluded from study. Agreement between the two methods was excellent (linear regression r = 0.98, slope = 1.07, y-intercept = -4.5 ml, range 403 to 5.540 ml/minute). The Doppler technique is a quick, noninvasive, and accurate method of determining ascending aortic blood flow in neonates and children.

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.

The Empirical Foundations of Telemedicine Interventions for Chronic Disease Management

The telemedicine intervention in chronic disease management promises to involve patients in their own care, provides continuous monitoring by their healthcare providers, identifies early symptoms, and responds promptly to exacerbations in their illnesses. This review set out to establish the evidence from the available literature on the impact of telemedicine for the management of three chronic diseases: congestive heart failure, stroke, and chronic obstructive pulmonary disease. By design, the review focuses on a limited set of representative chronic diseases because of their current and increasing importance relative to their prevalence, associated morbidity, mortality, and cost. Furthermore, these three diseases are amenable to timely interventions and secondary prevention through telemonitoring. The preponderance of evidence from studies using rigorous research methods points to beneficial results from telemonitoring in its various manifestations, albeit with a few exceptions. Generally, the benefits include reductions in use of service: hospital admissions/re-admissions, length of hospital stay, and emergency department visits typically declined. It is important that there often were reductions in mortality. Few studies reported neutral or mixed findings.

National telemedicine initiatives: essential to healthcare reform.

Contributing authors: Elizabeth A. Krupinski, Ph.D.,3 Jim Grigsby, Ph.D.,4 Joseph C. Kvedar, M.D.,5 Ronald S. Weinstein, M.D.,3 Jay H. Sanders, M.D.,6 Karen S. Rheuban, M.D.,7 Thomas S. Nesbitt, M.D.,8 Dale C. Alverson, M.D.,9 Ronald C. Merrell, M.D.,10 Jonathan D. Linkous,11 A. Stewart Ferguson, Ph.D.,12 Robert J. Waters, J.D.,13 Max E. Stachura, M.D.,14 David G. Ellis, M.D.,15 Nina M. Antoniotti, Ph.D.,16 Barbara Johnston, M.S.N.,17 Charles R. Doarn, M.B.A.,18 Peter Yellowlees, M.D.,19 Steven Normandin,20 and Joseph Tracy 21

Effect of patent ductus arteriosus on left ventricular output in premature infants

A 5 MHz range-gated portable pulsed Doppler velocity meter was used to measure mean ascending aortic blood flow velocity noninvasively. Studies were performed from a suprasternal approach in 18 preterm infants with patent ductus arteriosus. Measurements were made in each patient before and after medical or surgical closure of the PDA. The internal ascending aortic diameter was determined echocardiographically and aortic cross-sectional area calculated according to the equation AAo = pi d2/4. Ascending aortic blood flow was computed as QAo (ml/min) = VAo (cm/sec) x AAo (cm2) x 60 (sec/min). Prior to PDA closure, QAo averaged 343 ml/min/kg, well above predicted normal values. After PDA closure, QAo fell to 252 ml/min/kg, significantly lower than the preclosure level (P less than 0.001), but slightly higher than the mean cardiac output of healthy newborn infants. The mean QAo after surgical ligation of the PDA was closer to the predicted normal value than after treatment with indomethacin alone. This study reflects the effect of left-to-right ductus shunting on left ventricular output and emphasizes the demands placed on the neonatal left ventricle by PDA.

Effect of booster blood transfusions on oxygen utilization in infants with bronchopulmonary dysplasia

To assess the impact of booster transfusions on oxygen utilization in infants with bronchopulmonary dysplasia, we noninvasively measured oxygen consumption (VO2) and the variables of systemic oxygen transport (SOT) before and 24 hours after transfusion therapy in 10 oxygen-dependent infants with bronchopulmonary dysplasia. The infants had been born with a mean gestational age of 27.6 weeks and a mean birth weight of 0.88 kg. Study weight averaged 1.24 +/- 0.35 kg, and study age averaged 5.5 +/- 2.4 weeks. Requirements for fractional concentration of inspired oxygen averaged 0.41 +/- 0.15 to maintain an oxygen saturation of 0.93 +/- 0.02. The VO2 was measured by means of a commercially available analyzer through a flow-through circuit and pump connected to a hood or in line with the ventilator. Cardiac output was calculated by means of pulsed Doppler ultrasonography. Oxygen saturation was measured by means of transcutaneous pulse oximetry. The coefficient of oxygen utilization was calculated as VO2/SOT. Transfusion consisted of packed erythrocytes (10 ml/kg). Oxygen utilization fell in all subjects after transfusion (p less than 0.01), but it fell more substantially in subjects with higher coefficients of oxygen utilization (r = -0.80, p less than 0.01), suggesting a physiologic benefit in selected patients, particularly those with higher levels of oxygen utilization. There was also a significant increase in overall systemic oxygen transport (p less than 0.01) and decrease in VO2 (p less than 0.02). Hemoglobin levels alone did not correlate with overall systemic oxygen transport, VO2, or level of oxygen use before transfusion, and thus did not predict which subjects would have a physiologic benefit from transfusion as reflected by falls in oxygen utilization.

Assessing or Predicting Adoption of Telehealth Using the Diffusion of Innovations Theory: A Practical Example from a Rural Program in New Mexico

In New Mexico, a large rural state, it was anticipated that telehealth would bring significant value to health care delivery, improve local capacity for patient care, decrease the need for patient travel, diminish professional isolation, provide an avenue for enhanced professional education and information sharing, increase access to care, and ultimately improve health status. During the course of an evaluation of the University of New Mexico Center for Telehealths rural telemedicine program, we used a grounded theory approach to assess barriers to the adoption of telemedicine and components of successful adoption. We then turned to the diffusion of innovations theory to better understand the dynamic interactions between the characteristics of telehealth and the social system in which it is applied. In doing so, we learned that the type of innovation decision involved in the adoption of telehealth appears to be particularly important in determining adoption. In this article we demonstrate that diffusion theory can be a useful framework for evaluating telehealth programs. We also suggest that the development of a predictive tool for prospective assessment would be useful, and could be applied when new telehealth programs are being planned.

One Size Doesn’t Fit All: Bringing Telehealth Services to Special Populations

Telehealth applications and information communication technologies can be customized and scaled to meet the healthcare service needs of a wide variety of special populations. Categorization of those special groups can be viewed from a spectrum of perspectives such as by gender, age, culture, families, communities, chronic conditions, or particular types of locations, as well as when addressing a specific or unique health need. The emergence of innovations in the use of a range of technologies and connectivity offers exciting new approaches to the integration of telehealth aimed at improving quality and continuity of care to better meet the needs of special populations.

Hemodynamic consequences of neonatal polycythemia

The hemodynamic consequences of neonatal polycythemic hyperviscosity and the effects of partial exchange transfusion were evaluated in 13 infants. Mean (+/- SD) venous hematocrit was 72% +/- 2.5%. After partial exchange transfusion, whole blood viscosity at a shear rate of 11.5 sec-1 decreased from 16.2 to 8.4 centipoise. There were significant (P less than 0.05) increases in heart rate (127 +/- 7.5 to 139 +/- 7.8 beats/min), Doppler-derived cardiac index (200 +/- 35 to 263 +/- 48 ml/kg/min), left ventricular stroke volume index (1.56 +/- 0.23 to 1.89 +/- 0.33 ml/kg), systemic oxygen transport (51.4 +/- 8.4 to 57.9 +/- 11.9 ml/kg/min), and laser-Doppler peripheral (cutaneous) blood flow (+80%) after partial exchange transfusion. The increase in cardiac index probably resulted from reductions in pulmonary and systemic vascular resistance index, the latter decreasing from 0.26 to 0.19 mm Hg/ml/min/kg-1. The greater increase in cutaneous blood flow (+80%) versus cardiac index (+32%) after exchange transfusion suggests hemodynamic compromise and a redistribution of blood flow away from organs that use little oxygen during polycythemia. Our data provide a possible basis for the symptoms of neonatal polycythemia, and demonstrate the acute hemodynamic benefits of partial exchange transfusion.

Applying Telehealth in Natural and Anthropogenic Disasters

There are myriad telehealth applications for natural or anthropogenic disaster response. Telehealth technologies and methods have been demonstrated in a variety of real and simulated disasters. Telehealth is a force multiplier, providing medical and public health expertise at a distance, minimizing the logistic and safety issues associated with on-site care provision. Telehealth provides a virtual surge capacity, enabling physicians and other health professionals from around the world to assist overwhelmed local health and medical personnel with the increased demand for services postdisaster. There are several categories of telehealth applications in disaster response, including ambulatory/primary care, specialty consultation, remote monitoring, and triage, medical logistics, and transportation coordination. External expertise would be connected via existing telehealth networks in the disaster area or specially deployed telehealth systems in shelters or on-scene. This paper addresses the role of telehealth in disaster response and recommends a roadmap for its widespread use in preparing for and responding to natural and anthropogenic disasters.