title: The effects of endotracheal suctioning on the accuracy of oxygen consumption and carbon dioxide production measurements and pulmonary mechanics calculated by a compact metabolic monitor.
abstract: BACKGROUND
  Open endotracheal suctioning (ETS), which is performed regularly in mechanically ventilated patients to remove obstructive secretions, can cause an immediate decrease in dynamic compliance and expired tidal volume and result in inadequate or inaccurate sidestream respiratory monitoring, necessitating prolonged periods of stabilization of connected metabolic monitors. We investigated the immediate effect of open ETS on the accuracy of oxygen consumption (VO2) and carbon dioxide production (VCO2) measurements and calculated lung mechanics, respiratory quotient, and resting energy expenditure in mechanically ventilated children without severe lung pathology, when using a compact modular metabolic monitor (E-COVX) continuously recording patient spirometry and gas exchange measurements.
  
  
  METHODS
  Open ETS was performed when clinically indicated in 11 children mechanically ventilated for sepsis or head injury. A total of 2800 pulmonary 1-min gas exchange measurements were recorded in 28 ETS instances for 50 consecutive minutes before and 50 min after the standardized procedure.
  
  
  RESULTS
  Pulmonary mechanics and indirect calorimetry did not differ between pre- and postsuction sets of measurements. Pre- and postsuction VO2, VCO2, dynamic airway resistance, dynamic compliance, and expiratory minute ventilation remained stable from 5 to 55 min after tracheal suctioning and did not differ among different ventilatory modes. Average paired differences of sequential pre- and postsuction VO2, VCO2, respiratory quotient, and resting energy expenditure were -0.6%, -1%, -0.1%, and -0.3%. Ratio differences between the first and the second periods of measurements (1-25 vs 26-50 sets of 1-min measurements) did not differ in the two groups.
  
  
  CONCLUSIONS
  Pulmonary mechanics and indirect calorimetry measurements are not influenced after uneventful open ETS in well-sedated patients. The E-COVX is able to reliably record spirometry and metabolic indices as early as 5 min after suctioning at different ventilator modes.
authors.affiliation: Pediatric Intensive Care Unit, University Hospital, University of Crete, Heraklion, Greece. ggbriass@otenet.gr
authors.forename: George
authors.initials: G
authors.lastname: Briassoulis
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Briassoulis
authors.forename: Evi
authors.initials: E
authors.lastname: Michaeloudi
authors.forename: Diana-Michaela
authors.initials: DM
authors.lastname: Fitrolaki
authors.forename: Anna-Maria
authors.initials: AM
authors.lastname: Spanaki
authors.forename: Efrossini
authors.initials: E
authors.lastname: Briassouli
mesh_terms: D000293:Adolescent; D002245:Carbon Dioxide / Q000378:metabolism*; D002648:Child; D006259:Craniocerebral Trauma / Q000628:therapy; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal / Q000379:methods; D008297:Male; D016343:Monitoring, Intraoperative / Q000295:instrumentation / Q000379:methods*; D010100:Oxygen / Q000737:chemistry; D010101:Oxygen Consumption; D011659:Pulmonary Gas Exchange; D015203:Reproducibility of Results; D012121:Respiration, Artificial / Q000295:instrumentation / Q000379:methods*; D018805:Sepsis / Q000473:pathology; D016896:Treatment Outcome
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen