title: Normal saline instillation before suctioning: A meta-analysis of randomized controlled trials.
abstract: BACKGROUND
  For airway management of intensive care unit (ICU) patients who are intubated, a 5-10-mL bolus of sterile normal saline (NS) solution is commonly instilled into an endotracheal or tracheostomy tube before suctioning. However, NS instillation has been associated with adverse events such as dyspnea, increasing heart rate, decreasing of oxygenation, blood pressure, and other vital parameters.
  
  
  OBJECTIVE
  To conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate the necessity of NS instillation before suctioning in ICU patients.
  
  
  METHODS
  The PubMed, Embase, Cochrane Library, and Scopus databases and the ClinicalTrials.gov registry were searched for studies published before May 2016.
  
  
  METHODS
  RCTs evaluating the outcome of NS instillation before suctioning in ICU patients undergoing endotracheal intubation or tracheostomy were included. Individual effect sizes were standardised, and a meta-analysis was conducted to calculate the pooled effect size by using a random-effect model. The primary outcome was the oxygen saturation immediately and 2 and 5min after suctioning. The secondary outcomes were the heart rate and blood pressure after suctioning.
  
  
  RESULTS
  We reviewed 5 RCTs including 337 patients. Oxygen saturation was significantly higher in the non-NS group than in the NS group 5min after suctioning. The pooled mean difference in oxygen saturation was -1.14 (95% confidence interval: -2.25 to -0.03). The heart rate and blood pressure did not differ significantly between the non-NS and NS groups.
  
  
  CONCLUSIONS
  NS instillation before suctioning does not benefit patients undergoing endotracheal intubation or tracheostomy. Moreover, it reduces oxygen saturation 5min after suction. However, our reviewed studies had a low methodological quality. Thus, additional studies involving large-scale RCTs are warranted.
authors.affiliation: Department of Nursing, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan; School of Nursing, College of Nursing, Taipei Medical University, Taipei, Taiwan.
authors.forename: Chia-Hui
authors.initials: CH
authors.lastname: Wang
authors.affiliation: Department of Nursing, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan; School of Nursing, College of Nursing, Taipei Medical University, Taipei, Taiwan.
authors.forename: Jui-Chen
authors.initials: JC
authors.lastname: Tsai
authors.affiliation: Department of Nursing, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan; School of Nursing, College of Nursing, Taipei Medical University, Taipei, Taiwan.
authors.forename: Shu-Fen
authors.initials: SF
authors.lastname: Chen
authors.affiliation: School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Thoracic Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.
authors.forename: Chien-Ling
authors.initials: CL
authors.lastname: Su
authors.affiliation: Center for Evidence-Based Health Care, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Chen
authors.affiliation: Center for Evidence-Based Health Care, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.
authors.forename: Chao-Chun
authors.initials: CC
authors.lastname: Lin
authors.affiliation: Center for Evidence-Based Health Care, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan; Division of General Surgery, Department of Surgery, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan; Department of Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taiwan; Cochrane Taiwan, Taipei Medical University, Taipei, Taiwan. Electronic address: kelvintam@h.tmu.edu.tw.
authors.forename: Ka-Wai
authors.initials: KW
authors.lastname: Tam
mesh_terms: D001794:Blood Pressure / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007362:Intensive Care Units; D007442:Intubation, Intratracheal / Q000451:nursing*; D010100:Oxygen / Q000097:blood; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors; D012965:Sodium Chloride / Q000008:administration & dosage*; D013396:Suction / Q000451:nursing*; D014139:Tracheostomy / Q000451:nursing*
chemical_list: D012965:Sodium Chloride; D010100:Oxygen
keywords: Meta-analysis; Normal saline instillation; Oxygen saturation; Suctioning