title: Infusion System Architecture Impacts the Ability of Intensive Care Nurses to Maintain Hemodynamic Stability in a Living Swine Simulator.
abstract: BACKGROUND
  The authors have previously shown that drug infusion systems with large common volumes exhibit long delays in reaching steady-state drug delivery and pharmacodynamic effects compared with smaller common-volume systems. The authors hypothesized that such delays can impede the pharmacologic restoration of hemodynamic stability.
  
  
  METHODS
  The authors created a living swine simulator of hemodynamic instability in which occlusion balloons in the aorta and inferior vena cava (IVC) were used to manipulate blood pressure. Experienced intensive care unit nurses blinded to the use of small or large common-volume infusion systems were instructed to maintain mean arterial blood pressure between 70 and 90 mmHg using only sodium nitroprusside and norepinephrine infusions. Four conditions (IVC or aortic occlusions and small or large common volume) were tested 12 times in eight animals.
  
  
  RESULTS
  After aortic occlusion, the time to restore mean arterial pressure to range (t1: 2.4 ± 1.4 vs. 5.0 ± 2.3 min, P = 0.003, average ± SD), time-out-of-range (tOR: 6.2 ± 3.5 vs. 9.5 ± 3.4 min, P = 0.028), and area-out-of-range (pressure-time integral: 84 ± 47 vs. 170 ± 100 mmHg · min, P = 0.018) were all lower with smaller common volumes. After IVC occlusion, t1 (3.7 ± 2.2 vs. 7.1 ± 2.6 min, P = 0.002), tOR (6.3 ± 3.5 vs. 11 ± 3.0 min, P = 0.007), and area-out-of-range (110 ± 93 vs. 270 ± 140 mmHg · min, P = 0.003) were all lower with smaller common volumes. Common-volume size did not impact the total amount infused of either drug.
  
  
  CONCLUSIONS
  Nurses did not respond as effectively to hemodynamic instability when drugs flowed through large common-volume infusion systems. These findings suggest that drug infusion system common volume may have clinical impact, should be minimized to the greatest extent possible, and warrants clinical investigations.
authors.affiliation: From the Department of Anesthesiology, Pain Medicine, and Critical Care, Steward St. Elizabeth's Medical Center, Boston, Massachusetts (M.J.P., M.Y.M., R.R.G., M.A.L.); and Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts (R.A.P.).
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Pezone
authors.forename: Robert A
authors.initials: RA
authors.lastname: Peterfreund
authors.forename: Mikhail Y
authors.initials: MY
authors.lastname: Maslov
authors.forename: Radhika R
authors.initials: RR
authors.lastname: Govindaswamy
authors.forename: Mark A
authors.initials: MA
authors.lastname: Lovich
mesh_terms: D000818:Animals; D001011:Aorta / Q000502:physiology; D062186:Arterial Pressure; D021721:Balloon Occlusion; D001810:Blood Volume; D003422:Critical Care / Q000379:methods*; D004867:Equipment Design; D006439:Hemodynamics / Q000502:physiology*; D007260:Infusion Pumps; D009599:Nitroprusside / Q000008:administration & dosage / Q000494:pharmacology; D009638:Norepinephrine / Q000008:administration & dosage / Q000494:pharmacology; D009726:Nurses; D034421:Sus scrofa; D014662:Vasoconstrictor Agents / Q000008:administration & dosage / Q000494:pharmacology; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D009599:Nitroprusside; D009638:Norepinephrine