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Biomedical subjects

Charles T Quinn

Publications and source records attributed to Charles T Quinn.

9 recordsLinked to original sources
PubMed2007

Extracorporeal membrane oxygenation (ECMO) initiation without intubation in two children with mediastinal malignancy.

We report the cases of two children presenting with severe airway compromise secondary to a mediastinal malignancy managed with extracorporeal membrane oxygenation without intubation. Results are presented on the use of ECMO as a primary means of stabilizing a pediatric patient with a critical mediastinal mass, thus providing another management strategy for this difficult situation.

Antineoplastic Agents↗
PubMed2006

Prognostic significance of early vaso-occlusive complications in children with sickle cell anemia.

Sickle cell anemia (SS) is highly phenotypically variable, and early predictors of outcome could guide clinical care. To determine whether early vaso-occlusive complications predicted subsequent adverse outcomes in the Dallas Newborn Cohort, we studied all members with SS or sickle-beta0-thalassemia who presented in their first year of life and had 5 years or more of follow-up. We defined 3 potential early predictors: hospitalizations in the first 3 years of life for (1) painful events other than dactylitis, (2) dactylitis, and (3) acute chest syndrome (ACS). We studied the associations of these predictors with the following late adverse outcomes (occurring after the third birthday): death, first overt stroke, use of disease-modifying therapy, and hospitalizations for pain events and ACS. None of the early events predicted death or stroke. Early pain and ACS both predicted a modest, temporary increase in the number of later painful episodes, but early ACS strongly increased the odds of more frequent ACS throughout childhood. Dactylitis had limited utility as a predictor. Although we still lack a useful prognostic framework for young children with SS, those who experience early ACS might be candidates for higher risk interventions to mitigate or cure their disease.

Acute Disease↗
PubMed2005

Minor elective surgical procedures using general anesthesia in children with sickle cell anemia without pre-operative blood transfusion.

BACKGROUND: Pre-operative red blood cell (RBC) transfusions are often recommended for patients with sickle cell disease (SCD) who require elective surgery under general anesthesia. However, definitive randomized studies demonstrating the benefit of transfusions in this setting have not been conducted. In particular, the merits of transfusion prior to minor or low-risk surgical procedures in children with SCD have not been demonstrated. PROCEDURE: We hypothesized that children with sickle cell anemia (Hb SS) who have minor elective surgical procedures develop few complications even without pre-operative transfusion. We accessed our Comprehensive Sickle Cell Program's Database to identify all such procedures performed during a 13-year period. Medical records were reviewed to characterize the surgical procedure, the use of transfusions, and perioperative complications. RESULTS: Twenty-eight children with Hb SS had a total of 38 minor surgical procedures. No perioperative transfusions were given in 34 of the cases (85%). Five of these 34 surgeries (15%) were associated with minor post-operative complications (fever or transient pain). No post-operative acute chest syndrome was encountered. CONCLUSIONS: Minor or low-risk elective surgical procedures in children with Hb SS may not routinely require pre-operative transfusion. A randomized clinical trial to compare transfusion with no transfusion for minor surgical procedures is needed.

Adolescent↗
PubMed2005

Clinical correlates of steady-state oxyhaemoglobin desaturation in children who have sickle cell disease.

Individuals with sickle cell disease (SCD) may have oxyhaemoglobin desaturation during the steady-state, the causes of which are incompletely known. We studied a cohort of 585 children who have sickle cell anaemia (SS), sickle beta0-thalassaemia (Sbeta0), sickle-haemoglobin C disease (SC), or sickle beta+-thalassaemia (Sbeta+) to determine the relationships between steady-state oxyhaemoglobin saturation (SpO2) and SCD genotype, age, gender, steady-state haemoglobin (Hb) and reticulocyte count, and rate of acute chest syndrome (ACS). The SS/Sbeta0 group (n = 390) had lower mean SpO2 than the SC/Sbeta+ group (n = 195) (96.3% vs. 98.7%, P < 0.001). Among SS/Sbeta0 subjects, a decrease in steady-state SpO2 correlated with a decrease in Hb, an increase in reticulocytes, older age and male gender. These correlations were not found in the SC/Sbeta+ group. Prior ACS did not correlate with steady-state SpO2. A multivariate model explained 45% of the variability in SpO2, but only 5% of the variation in SpO2 was explained by Hb. We conclude that steady-state desaturation is common in individuals with SCD, but it appears to be unrelated to prior episodes of ACS and largely unexplained by chronic anaemia.

Adolescent↗
PubMed2004

Survival of children with sickle cell disease.

Contemporary survival data are not available for children with sickle cell disease (SCD). The few previous childhood SCD cohort studies do not reflect the benefits of modern therapy. We defined an inception cohort of newborns with sickle cell anemia (SS), sickle-beta degrees -thalassemia (S beta degrees ), sickle-hemoglobin C disease (SC), or sickle-beta(+)-thalassemia (Sbeta(+)) who were identified by newborn screening and followed for up to 18 years. The incidence of death and stroke were calculated. Overall survival, SCD-related survival (considering only SCD-related deaths), and strokefree survival were determined. The 711 subjects provided 5648 patient-years of observation. Twenty-five subjects died; mean age at death was 5.6 years. Five patients died from infection. Thirty had at least one stroke. Among SS and Sbeta degrees subjects (n = 448), the overall rates of death and stroke were 0.59 and 0.85/100 patient-years. Survival analysis of SS and Sbeta degrees subjects predicted the cumulative overall, SCD-related, and stroke-free survival to be 85.6%, 93.6%, and 88.5% by 18 years of age. No SCD-related deaths or strokes occurred in SC or Sbeta(+) subjects (n = 263). Childhood mortality from SCD is decreasing, the mean age at death is increasing, and a smaller proportion of deaths are from infection.

Adolescent↗
PubMed2004

Effects of intraventricular methotrexate on folate, adenosine, and homocysteine metabolism in cerebrospinal fluid.

Methotrexate (MTX) is an antifolate that affects many metabolic pathways. MTX may cause neurologic toxicity, but the biochemical effects of MTX on the central nervous system (CNS) are poorly characterized. The authors studied serial cerebrospinal fluid (CSF) samples from a child during two courses of intraventricular MTX and found a rapid and reproducible depletion in CSF of reduced folates and S-adenosylmethionine that was accompanied by marked increases in homocysteine and adenosine. No sulfur-containing excitatory amino acids were detected. This study demonstrates multiple profound effects of MTX on CNS metabolism and provides insight to the pathogenesis of MTX neurotoxicity.

Amino Acids↗
PubMed2004

Sickle cell disease.

Much progress has been made during the past several decades in gaining understanding about the natural history of sickle cell disease and management approaches aimed at treating or even preventing certain disease complications. The characterization of the human genome now offers the opportunity to understand relationships regarding how gene polymorphisms as well as how environmental factors affect the sickle cell disease phenotype, i.e., the individual patient's overall clinical severity as well as their specific organ function. This chapter explores some of these recent advances in knowledge. In Section I, Dr. Michael DeBaun characterizes the problem of silent stroke in sickle cell disease, comparing and contrasting its clinical and neuroimaging features with overt stroke. Combined, these events affect virtually 40% of children with sickle cell anemia. New understanding of risk factors, associated clinical findings, and imaging technologies are impacting substantially on treatment options. The appreciable cognitive dysfunction and other sequelae of silent infarct demand more effective treatments and ultimate prevention. In Section II, Dr. Charles Quinn addresses the conundrum of why some patients with sickle cell disease do well whereas others fare poorly. Some risk factors have been known for years, based upon careful study of hundreds of patients by the Cooperative Study for Sickle Cell Disease and investigators studying the Jamaican newborn cohort. Other prognostic measures have only recently been defined. Dr. Quinn devotes special attention to stroke and chest syndrome as organ-related complications but also describes attempts to measure overall disease severity and to predict survival. Recently, investigators have attempted to predict factors responsible for early mortality in children and following onset of pulmonary hypertension in adults. In Section III, Dr. Martin Steinberg reviews pharmacologic approaches to sickle cell disease and the rationale for their use. In addition to the inhibition of hemoglobin S polymerization, newer targets have been defined during the past one to two decades. These include the erythrocyte membrane, changes in the red cell intracellular content (especially loss of water), endothelial injury, and free radical production. Hydroxyurea treatment attracted the greatest interest, but many uncertainties remain about its long-term benefits and toxicities. Newer "anti-sickling" agents such as decitabine and short-chain fatty acids also receive attention. Prevention of red cell dehydration, "anti-endothelial" therapy, and marshalling the potentially beneficial effects of nitric oxide are other new and exciting approaches.

Anemia, Sickle Cell↗