Bio

Clinical Focus


  • Pediatric Critical Care Medicine

Academic Appointments


Professional Education


  • Board Certification: Pediatrics, American Board of Pediatrics (2004)
  • Board Certification: Pediatric Critical Care Medicine, American Board of Pediatrics (2006)
  • Fellowship:The Children's Hospital of Philadelphia (2006) PA
  • Residency:UT Southwestern - Children's Medical Center of Dallas (2003) TX
  • Medical Education:Feinberg School of Medicine - Northwestern University (2000) IL

Research & Scholarship

Current Research and Scholarly Interests


My research is focused on investigating the impact of dynamic organ function on drug disposition and designing dosing strategies based on mathematical models that account for these changes in order to optimize safe medication administration in critically ill children.

Publications

Journal Articles


  • A Dose-Response Study of Dexmedetomidine Administered as the Primary Sedative in Infants Following Open Heart Surgery PEDIATRIC CRITICAL CARE MEDICINE Su, F., Nicolson, S. C., Zuppa, A. F. 2013; 14 (5): 499-507

    Abstract

    OBJECTIVE:: To evaluate the dose-response relationship of dexmedetomidine in infants with congenital heart disease postoperative from open heart surgery. DESIGN:: Prospective open-label dose-escalation pharmacokinetic-pharmacodynamic study. SETTING:: Tertiary pediatric cardiac ICU. PATIENTS:: Thirty-six evaluable infants, 1-24 months old, postoperative from open heart surgery requiring mechanical ventilation. INTERVENTIONS:: Cohorts of 12 infants were enrolled sequentially to one of the three IV loading doses of dexmedetomidine (0.35, 0.7, and 1 mcg/kg) over 10 minutes followed by respective continuous infusions (0.25, 0.5, and 0.75 mcg/kg/hr) for up to 24 hours. MEASUREMENTS AND MAIN RESULTS:: Dexmedetomidine plasma concentrations were obtained at timed intervals during and following discontinuation of infusion. Pharmacodynamic variables evaluated included sedation scores, supplemental sedation and analgesia medication administration, time to tracheal extubation, respiratory function, and hemodynamic parameters. Infants achieved a deeper sedation measured by the University of Michigan Sedation Scale score (2.6 vs 1) despite requiring minimal supplemental sedation (0 unit doses/hr) and fewer analgesic medications (0.07 vs 0.15 unit doses/hr) while receiving dexmedetomidine compared with the 12-hour follow-up period. Thirty-one patients were successfully extubated while receiving the dexmedetomidine infusion. Only one patient remained intubated due to oversedation during the infusion. While receiving dexmedetomidine, there was a decrease in heart rate compared with baseline, 132 versus 161 bpm, but there was an increase in heart rate compared with postinfusion values, 132 versus 128 bpm. There was no statistically or clinically significant change in mean arterial blood pressure. CONCLUSIONS:: Dexmedetomidine administration in infants following open heart surgery can provide improved sedation with reduction in supplemental medication requirements, leading to successful extubation while receiving a continuous infusion. The postoperative hemodynamic changes that occur in infants postoperative from open heart surgery are multifactorial. Although dexmedetomidine may play a role in decreasing heart rate immediately postoperative, the changes were not clinically significant and did not fall below postinfusion heart rates.

    View details for DOI 10.1097/PCC.0b013e31828a8800

    View details for Web of Science ID 000319920300016

    View details for PubMedID 23628837

  • Dexmedetomidine: pediatric pharmacology, clinical uses and safety EXPERT OPINION ON DRUG SAFETY Su, F., Hammer, G. B. 2011; 10 (1): 55-66

    Abstract

    Dexmedetomidine is an ?(2)-adrenoceptor agonist with sedative, anxiolytic and analgesic properties. It is used off-label in pediatric patients due to its efficacy and lack of adverse respiratory effects. Dexmedetomidine may cause severe circulatory complications in adults. Despite its popularity, the safety of dexmedetomidine in the pediatric population has not been extensively studied.This article reviews the current literature (up to 2010) focusing on applications and safety of dexmedetomidine administered to pediatric patients.Dexmedetomidine is a useful sedative and anxiolytic drug in the pediatric intensive care unit as well as during diagnostic and therapeutic procedures. Deleterious effects of dexmedetomidine include hypotension and bradycardia. Additionally, hypertension may occur during the "loading dose" or with high infusion rates. Few studies have been performed to evaluate the safety of dexmedetomidine in pediatrics. The development of tolerance and withdrawal has not been studied in children.Despite its favorable respiratory profile, dexmedetomidine may cause deleterious cardiovascular effects. Close monitoring of circulatory dynamics and judicious titration is recommended. Further studies are needed to better define adverse effects following long-term infusions as well as in special populations such as pre-term infants.

    View details for DOI 10.1517/14740338.2010.512609

    View details for Web of Science ID 000285388700007

    View details for PubMedID 20718689

  • Population Pharmacokinetics of Dexmedetomidine in Infants After Open Heart Surgery ANESTHESIA AND ANALGESIA Su, F., Nicolson, S. C., Gastonguay, M. R., Barrett, J. S., Adamson, P. C., Kang, D. S., Godinez, R. I., Zuppa, A. F. 2010; 110 (5): 1383-1392

    Abstract

    Dexmedetomidine is a highly selective alpha(2)-agonist with hypnotic, analgesic, and anxiolytic properties. In adults, it provides sedation while preserving respiratory function facilitating extubation. Only limited pharmacokinetic data are available for pediatric patients. The primary aim of this study was to determine the pharmacokinetics of dexmedetomidine in infants after open heart surgery.We evaluated 36 infants, aged 1 to 24 months, after open heart surgery. Cohorts of 12 infants requiring mechanical ventilation after open heart surgery were enrolled sequentially to 1 of the 3 initial loading dose-continuous IV infusion (CIVI) regimens: 0.35-0.25, 0.7-0.5, or 1-0.75 microg/kg-microg/kg/h. The initial loading dose was administered over 10 minutes immediately postoperatively followed by a CIVI of up to 24 hours. Plasma dexmedetomidine concentrations were determined using a validated high-performance liquid chromatography tandem mass spectrometry assay. A population nonlinear mixed effects modeling approach was used to characterize dexmedetomidine pharmacokinetics.Pharmacokinetic parameters of dexmedetomidine were estimated using a 2-compartment disposition model with weight on drug clearance, intercompartmental clearance, central and peripheral volume of distributions, total bypass time as a covariate on clearance and central volume of distribution, and age and ventricular physiology as covariates on clearance. Infants demonstrated a clearance of 28.1 mL/min/kg(0.75), intercompartmental clearance of 93.4 mL/min/kg(0.75), central volume of distribution of 1.2 L/kg, and peripheral volume of distribution of 1.5 L/kg.Dexmedetomidine clearance increased with weight, age, and single-ventricle physiology, whereas total bypass time was associated with a trend toward decreasing clearance, and central volume of distribution increased as a function of total bypass time. The dependence of clearance on body weight supports current practice of weight-based dexmedetomidine dosing, whereas the clinical impact of the remaining covariate effects requires further investigation. Initial loading doses in the range of 0.35 to 1 microg/kg over 10 minutes and CIVI of 0.25 to 0.75 microg/kg/h were well tolerated in this infant population.

    View details for DOI 10.1213/ANE.0b013e3181d783c8

    View details for Web of Science ID 000277130700023

    View details for PubMedID 20418300

  • Sensitive and specific liquid chromatography-tandem mass spectrometric method for the quantitation of dexmedetomidine in pediatric plasma JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES Lee, J. I., Su, F., Shi, H., Zuppa, A. F. 2007; 852 (1-2): 195-201

    Abstract

    Dexmedetomidine (Dex) is a lipophilic imidazole derivative used primarily for the sedation and anxiolysis of adults in the intensive care setting. Dex is being used more frequently in the pediatric intensive care unit. This report describes a selective and highly sensitive assay for Dex in pediatric plasma employing liquid chromatography-tandem mass spectrometry (LC-MS/MS). Dex was extracted from 200 microL of plasma by solid-phase extraction (SPE). High performance liquid chromatography (HPLC) separation was conducted on an YMC ODS-AQ C(18) column with a flow rate of 0.3 mL/min using a mobile phase comprised of 5 mM ammonium acetate buffer/0.03% formic acid in the solvent mixture of methanol/acetonitrile/water (20:20:60, v/v/v). The intra-day precision (coefficient of variation, % CV) and accuracy for quality control samples, ranged from 1.04 to 6.84% and 90.2 to 100.8%, respectively. The inter-day precision and accuracy ranged from 4.08 to 5.37% and 92.7 to 98.6%, respectively. Stability studies showed that Dex was stable during both the assay procedure and storage. The overall recovery was 76.6-78.3% for Dex in plasma. The analytical method showed excellent sensitivity using a small sample volume (200 microL) with a lower limit of quantitation of 5 pg/mL. This method is robust and has been successfully employed in a pharmacokinetic study of Dex in infants postoperative from cardiac surgery.

    View details for DOI 10.1016/j.jchromb.2007.01.013

    View details for Web of Science ID 000247286700027

    View details for PubMedID 17267303

  • Untying the Gordian knot ANESTHESIA AND ANALGESIA Su, F., Zuppa, A. F., Adamson, P. C. 2007; 104 (4): 993-993
  • A toddler with obtundation and miosis PEDIATRIC EMERGENCY CARE Su, F., Schwab, S., Lin, R., Henretig, F., Osterhoudt, K. C. 2005; 21 (3): 211-213

    View details for Web of Science ID 000227653100013

    View details for PubMedID 15744203

  • Regulation of CCR5 and CXCR4 expression by type 1 and type 2 cytokines: CCR5 expression is downregulated by IL-10 in CD4-positive lymphocytes CLINICAL IMMUNOLOGY Patterson, B. K., Czerniewski, M. A., Andersson, J., Sullivan, Y., Su, F., Jiyamapa, D., Burki, Z., Landay, A. 1999; 91 (3): 254-262

    Abstract

    HIV-1 transmission and disease progression is, in general, characterized by initial predominance of macrophage tropic, non-syncytium-inducing strains followed by a switch to T-cell tropic, syncytium-inducing strains. Using sensitive, quantitative kinetic RT-PCR, we examined cytokine regulation of tropism-specific HIV-1 coreceptor expression in PBMCs from HIV-1-seronegative individuals. Proinflammatory (TNF-alpha and IL-12) and type 1 cytokines (IFN-gamma and IL-2) significantly upregulated CCR5 (wt allele) mRNA expression in CCR5 homozygous wild-type (wt/wt) and heterozygous individuals (wt/del) (P < 0.02). CCR5 (wt) mRNA expression in unstimulated PBMCs was significantly increased in wt/wt individuals compared to that of wt/del individuals (P < 0.01). In wt/del individuals, del CCR5 mRNA was expressed at 10-fold greater levels than wt CCR5 mRNA in unstimulated PBMCs from the same individual. Flow cytometry confirmed that upregulated CCR5 mRNA following type 1 cytokine stimulation leads to increased cell surface expression of CCR5 protein. The type 2 cytokine IL-10 downregulated both CCR5 mRNA and protein expression in wt/wt and wt/del individuals. Proinflammatory, type 1, and type 2 cytokines significantly increased CXCR4 mRNA expression in wt/wt, wt/del, and del/del CCR5 genotypes (P < 0.02). These results suggest that changes in the cytokine milieu influence chemokine receptor expression and may explain emergence of tropism-specific strains facilitating HIV transmission and disease progression.

    View details for Web of Science ID 000080635800002

    View details for PubMedID 10370370

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