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D B Swedlow

Publications and source records attributed to D B Swedlow.

15 recordsLinked to original sources
PubMed1990

Capnography.

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Carbon Dioxide↗
PubMed1986

The heart is under the lower third of the sternum. Implications for external cardiac massage.

Current guidelines for cardiopulmonary resuscitation in children state that the heart lies under the midsternum in infancy and descends with age. To verify this statement, we studied 55 patients, aged 1 day to 19 years, including eight premature infants, during either routine chest x-ray films or right-sided heart angiography. Using a Cartesian coordinate system determined by radiopaque markers placed on the chest, and computer digitization, we located the center of each patient's cardiac silhouette and/or right ventricle. Using descriptive statistics, we found that the heart lay under the lower third of the sternum in all age groups. Analysis of variance indicated that there was no significant difference in this location between age groups. These results suggest that recommendations for external cardiac massage in infants and children may need to be revised.

Adolescent↗
PubMed1986

Factors influencing outcome of cardiopulmonary resuscitation in children.

We evaluated 47 pediatric patients after cardiopulmonary arrest. Patients entered the study with the onset of advanced life support. We followed them until death, or discharge from the hospital, occurred. We identified three groups of patients: long-term survivors, who survived to discharge, short-term survivors, who survived longer than 24 hours after CPR but not until discharge, and nonsurvivors, who died within 24 hours of their arrest. All of the long-term surviving patients were discharged from the hospital without gross neurologic deficit attributable to the arrest or resuscitation effort. Twenty-seven (57%) children were successfully resuscitated. Eighteen (38%) were long term-survivors, while nine (19%) were short-term survivors. Favorable outcome is associated with the following factors: inhospital arrest, extreme bradycardia as the presenting arrhythmia, successful resuscitation with only ventilation, oxygen and closed chest massage, and a duration of CPR of less than 15 minutes. Age, sex, and race, as well as pupillary reaction and motor response at the onset of advanced life support, did not correlate with long-term survival.

Age Factors↗
PubMed1985

Open- versus closed-chest cardiac compressions in a canine model of pediatric cardiopulmonary resuscitation.

Whether or not the principles of adult resuscitation apply to the pediatric population remains unknown. In order to study this issue, a pediatric animal model was developed using puppies 6-12 weeks of age and 2-8 kg in weight. Hemodynamic status was assessed using standard methods, and measured global cerebral blood flow was assessed using the nitrous oxide (Kety-Schmidt) technique after placement of a catheter in the sagittal sinus. In this initial study, five puppies resuscitated with closed-chest cardiac compression (CCCC) were compared with five receiving open-chest cardiac compression (OCCC). Although mean systolic arterial pressures were equal with both methods during resuscitation (40 versus 49 mm Hg, P = 0.19), OCCC produced a greater cardiac output and a higher cerebral blood flow (5 versus 18 ml/100 g/min, P = 0.008). Only one of five dogs treated with CCCC had a blood flow during resuscitation greater than 15 ml/100 g/min, as compared with four of five receiving OCCC. Finally, three of five dogs in the CCCC group experienced liver lacerations, while none who were resuscitated by OCCC sustained any gross visceral injuries.

Animals↗
PubMed1985

Management of Reye's syndrome.

Reye's syndrome is a potentially devastating neurologic illness seen predominantly in children following a viral prodrome. The cause is unknown. The clinical history and laboratory presentation are stereotypical and easy to recognize if the clinician considers the diagnosis. Neurologic dysfunction is characterized by lethargy, obtundation, persistent vomiting, agitated delirium, and coma. Death is secondary to severe cerebral swelling with elevation of intracranial pressure. Although no specific therapy has been clearly demonstrated to be superior in terms of outcome, most clinicians have adopted a management scheme aimed at lowering and controlling the elevated ICP. We have described the management protocol in use at the Children's Hospital of Philadelphia. The protocol is summarized in the Appendix for the convenience of the reader.

Child↗
PubMed1983

Epinephrine-halothane interactions in children.

Cutaneous infiltration of dilute solutions of epinephrine for hemostasis during halothane anesthesia can result in ventricular dysrhythmias. Our clinical experience, published reports, and a study comparing piglets with adult swine suggest that children may be less susceptible than adults to dysrhythmias under these conditions. We therefore undertook a prospective survey of heart rate and rhythm in halothane-anesthesized children who received subcutaneous epinephrine for hemostasis. Mass spectrometry was used to quantify end-tidal halothane and to avoid hypercarbia. In 83 children anesthesized with halothane, we continuously recorded ECG, heart rate (HR), end-tidal halothane (ETHalo), and carbon dioxide (ETCO2). The surgeons injected 0.4--15.7 micrograms/kg of epinephrine (in saline or 1% lidocaine) to provide hemostasis at a variety of sites. No child developed a ventricular dysrhythmia. One child had self-limited premature atrial contractions (PAC). Sixty-three children had some increase in heart rate after epinephrine injection, while seven increased their HR 15% or more above pre-injection levels. No relation between any increase in HR and epinephrine dosage, ETHalo, ETCO2, physical status, or age was found by multiple linear regression; however, HR was increased significantly in patients receiving epinephrine in head and neck sites other than the palate. The authors conclude that children tolerate higher doses of subcutaneous epinephrine than adults during halothane anesthesia. The arrhythmogenic dose of epinephrine in children receiving halothane has yet to be determined, but at least 10 micrograms/kg of epinephrine infiltration may be used safely in normocarbic and hypocarbic pediatric patients without congenital heart disease. The presence of PAC and tachycardia emphasize the need for continuous ECG monitoring and caution during halothane anesthesia with epinephrine injection.

Adolescent↗
PubMed1975

Scanning and transmission electron microscopy of calcified tissues.

Some recent innovations have been utilized to extend studies of the structure of calcified tissues on the ultra- and microstructural levels of organization. The introduction of hydrazine as a replacement for the conventionally used ethylene diamine to deproteinize calcified tissue samples has resulted in the acquisition of previously unobtainable information about the mineral phase as it exists in situ. This enables inference of mineral-organic interrelationships when coupled with the EDTA demineralization technique used to study collagen fiber frameworks. In addition, a method for obtaining whole single osteons and separating them into lamellar constituents permits observations of the collagen-apatite orientation within successive lamellae of compact Haversian bone. The use of the structural information derived to develop a fiber-reinforced model of compact bone as a composite material is outlined and discussed.

Bone and Bones↗