title: Trial design: Computer guided normal-low versus normal-high potassium control in critically ill patients: Rationale of the GRIP-COMPASS study.
abstract: BACKGROUND
  Potassium depletion is common in hospitalized patients and can cause serious complications such as cardiac arrhythmias. In the intensive care unit (ICU) the majority of patients require potassium suppletion. However, there are no data regarding the optimal control target in critically ill patients. After open-heart surgery, patients have a strongly increased risk of atrial fibrillation or atrial flutter (AFF). In a novel trial design, we examined if in these patients different potassium control-targets within the normal range may have different effects on the incidence of AFF.
  
  
  METHODS
  The "computer-driven Glucose and potassium Regulation program in Intensive care Patients with COMparison of PotASSium targets within normokalemic range (GRIP-COMPASS) trial" is a single-center prospective trial in which a total of 1200 patients are assigned to either a potassium control-target of 4.0 mmol/L or 4.5 mmol/L in consecutive alternating blocks of 50 patients each. Potassium levels are regulated by the computer-assisted potassium suppletion algorithm called GRIP-II (Glucose and potassium regulation for Intensive care Patients). Primary endpoint is the in-hospital incidence of AFF after cardiac surgery. Secondary endpoints are: in-hospital AFF in medical patients or patients after non-cardiac surgery, actually achieved potassium levels and their variation, electrolyte and glucose levels, potassium and insulin requirements, cumulative fluid balance, (ICU) length of stay, ICU mortality, hospital mortality and 90-day mortality.
  
  
  CONCLUSIONS
  The GRIP-COMPASS trial is the first controlled clinical trial to date that compares potassium targets. Other novel methodological elements of the study are that it is performed in ICU patients where both targets are within the normal range and that a computer-assisted potassium suppletion algorithm is used.
  
  
  BACKGROUND
  NCT 01085071 at ClinicalTrials.gov.
authors.affiliation: Department of Anesthesiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9700 RB, Groningen, the Netherlands. m.hoekstra@thorax.umcg.nl.
authors.forename: Miriam
authors.initials: M
authors.lastname: Hoekstra
authors.forename: Mathijs
authors.initials: M
authors.lastname: Vogelzang
authors.forename: Iwan Cc
authors.initials: IC
authors.lastname: van der Horst
authors.forename: Annemieke Oude
authors.initials: AO
authors.lastname: Lansink
authors.forename: Joost Maa
authors.initials: JM
authors.lastname: van der Maaten
authors.forename: Farouq
authors.initials: F
authors.lastname: Ismael
authors.forename: Felix
authors.initials: F
authors.lastname: Zijlstra
authors.forename: Maarten Wn
authors.initials: MW
authors.lastname: Nijsten