title: Predictors of arterial blood pressure control during deliberate hypotension with sodium nitroprusside in children.
abstract: BACKGROUND
  Sodium nitroprusside (SNP) is used to decrease arterial blood pressure (BP) during certain surgical procedures. There are limited data regarding efficacy of BP control with SNP. There are no data on patient and clinician factors that affect BP control. We evaluated the dose-response relationship of SNP in infants and children undergoing major surgery and performed a quantitative assessment of BP control.
  
  
  METHODS
  One hundred fifty-three subjects at 7 sites received a blinded infusion followed by open-label SNP during operative procedures requiring controlled hypotension. SNP was administered by continuous infusion and titrated to maintain BP control (mean arterial BP [MAP] within ±10% of clinician-defined target). BP was recorded using an arterial catheter. Statistical process control methodology was used to quantify BP control. A multivariable model assessed the effects of patient and procedural factors.
  
  
  RESULTS
  BP was controlled an average 45.4% (SD 23.9%; 95% CI, 41.5%-49.18%) of the time. Larger changes in infusion rate were associated with worse BP control (7.99% less control for 1 μg·kg·min increase in average titration size, P = 0.0009). A larger difference between a patient's baseline and target MAP predicted worse BP control (0.93% worse control per 1-mm Hg increase in MAP difference, P = 0.0013). Both effects persisted in multivariable models.
  
  
  CONCLUSIONS
  SNP was effective in reducing BP. However, BP was within the target range less than half of the time. No clinician or patient factors were predictive of BP control, although 2 inverse relationships were identified. These relationships require additional study and may be best coupled with exposure-response modeling to propose improved dosing strategies when using SNP for controlled hypotension in the pediatric population.
authors.affiliation: From the Department of Pediatrics, Duke University School of Medicine, Durham, North Carolina; Department of Pediatrics, University of Pennsylvania Medical School, Philadelphia, Pennsylvania; Department of Anesthesia, Stanford School of Medicine, Stanford, California; and Duke Clinical Research Institute, Durham, North Carolina.
authors.forename: David R
authors.initials: DR
authors.lastname: Spielberg
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Barrett
authors.forename: Gregory B
authors.initials: GB
authors.lastname: Hammer
authors.forename: David R
authors.initials: DR
authors.lastname: Drover
authors.forename: Tammy
authors.initials: T
authors.lastname: Reece
authors.forename: Carol A
authors.initials: CA
authors.lastname: Cohane
authors.forename: Scott R
authors.initials: SR
authors.lastname: Schulman
mesh_terms: D000959:Antihypertensive Agents / Q000008:administration & dosage*; D062186:Arterial Pressure / Q000187:drug effects* / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007022:Hypotension / Q000139:chemically induced* / Q000175:diagnosis* / Q000503:physiopathology; D007223:Infant; D055104:Infusions, Subcutaneous; D008297:Male; D009599:Nitroprusside / Q000008:administration & dosage*; D011237:Predictive Value of Tests; D016037:Single-Blind Method
chemical_list: D000959:Antihypertensive Agents; D009599:Nitroprusside
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