title: Impact of Positive End-Expiratory Pressure on Thermodilution-Derived Right Ventricular Parameters in Mechanically Ventilated Critically Ill Patients.
abstract: OBJECTIVE
  To examine the effect of positive end-expiratory pressure (PEEP) on right ventricular stroke volume variation (SVV), with possible implications for the number and timing of pulmonary artery catheter thermodilution measurements.
  
  
  METHODS
  Prospective, clinical pilot study.
  
  
  METHODS
  Academic medical center.
  
  
  METHODS
  Patients who underwent volume-controlled mechanical ventilation and had a pulmonary artery catheter.
  
  
  METHODS
  PEEP was increased from 5-to-10 cmH2O and from 10-to-15 cmH2O with 10-minute intervals, with similar decreases in PEEP, from 15-to-10 cmH2O and 10-to-5 cmH2O.
  
  
  RESULTS
  In 15 patients, right ventricular parameters were measured using thermodilution at 10% intervals of the ventilatory cycle at each PEEP level with a rapid-response thermistor. Mean right ventricular stroke volume and end-diastolic volume declined during incremental PEEP and normalized on return to 5 cmH2O PEEP (p = 0.01 and p = 0.001, respectively). Right ventricular SVV remained unaltered by changes in PEEP (p = 0.26), regardless of incremental PEEP (p = 0.15) or decreased PEEP (p = 0.12). The coefficients of variation in the ventilatory cycle of all other thermodilution-derived right ventricular parameters also were unaffected by changes in PEEP.
  
  
  CONCLUSIONS
  This study showed that increases in PEEP did not affect right ventricular SVV in critically ill patients undergoing mechanical ventilation despite reductions in mean right ventricular stroke volume and end-diastolic volume. This could be explained by cyclic counteracting changes in right ventricular preloading and afterloading during the ventilatory cycle, independent of PEEP. Changes in PEEP did not affect the number and timing of pulmonary artery catheter thermodilution measurements.
authors.affiliation: Department of Intensive Care Medicine, Academic Medical Center, Amsterdam. Electronic address: t.g.cherpanath@amc.uva.nl.
authors.forename: Thomas G V
authors.initials: TG
authors.lastname: Cherpanath
authors.affiliation: Department of Intensive Care Medicine, Academic Medical Center, Amsterdam.
authors.forename: Wim K
authors.initials: WK
authors.lastname: Lagrand
authors.affiliation: Department of Intensive Care Medicine, Academic Medical Center, Amsterdam.
authors.forename: Jan M
authors.initials: JM
authors.lastname: Binnekade
authors.affiliation: Department of Clinical Pharmacology, VU University Medical Center, Amsterdam.
authors.forename: Anton J
authors.initials: AJ
authors.lastname: Schneider
authors.affiliation: Laboratory of Experimental Intensive Care and Anaesthesiology (LEICA), Academic Medical Center, Amsterdam.
authors.forename: Marcus J
authors.initials: MJ
authors.lastname: Schultz
authors.affiliation: Department of Intensive Care Medicine, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Johan A B
authors.initials: JA
authors.lastname: Groeneveld
mesh_terms: D000368:Aged; D002302:Cardiac Output / Q000502:physiology; D002407:Catheterization, Swan-Ganz / Q000379:methods; D016638:Critical Illness / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D010865:Pilot Projects; D011175:Positive-Pressure Respiration / Q000379:methods*; D011446:Prospective Studies; D013318:Stroke Volume / Q000502:physiology; D013815:Thermodilution / Q000379:methods; D016278:Ventricular Function, Right / Q000502:physiology*
keywords: cardiac output; positive end-expiratory pressure; pulmonary artery catheter; right ventricle; stroke volume variation; thermodilution