title: Gastric pH and residual volume after 1 and 2 h fasting time for clear fluids in children†.
abstract: BACKGROUND
  Current guidelines suggest a fasting time of 2 h for clear fluids, which is often exceeded in clinical practice, leading to discomfort, dehydration and stressful anaesthesia induction to patients, especially in the paediatric population. Shorter fluid fasting might be a strategy to improve patient comfort but has not been investigated yet. This prospective clinical trial compares gastric pH and residual volume after 1 vs 2 h of preoperative clear fluid fasting.
  
  
  METHODS
  Children (1-16 yr, ASA I or II) undergoing elective procedures in general anaesthesia requiring tracheal intubation were randomized into group A with 60 min or B with 120 min preoperative clear fluid fasting. To determine gastric pH and residual volume, the gastric content was sampled in supine, left and right lateral patient position using an oro-gastric tube after intubation. Data are median (interquartile range) for group A or B (P<0.05).
  
  
  RESULTS
  In total, 131 children aged 1.01-16.23 yr were included; gastric pH was determined in 120 cases. Patient characteristic data were similar between the two groups, except for gender (46/33 males in group A/B; P=0.02). Despite significantly shorter fasting times for clear fluids in group A compared with group B (76/136 min; P<0.001), no significant difference was observed regarding gastric pH [1.43 (1.30-1.56)/1.44 (1.29-1.68), P=0.66] or residual volume [0.43 (0.21-0.84)/0.46 (0.19-0.78) ml kg(-1), P=0.47].
  
  
  CONCLUSIONS
  One hour clear fluid fasting does not alter gastric pH or residual volume significantly compared with 2 h fasting.
  
  
  BACKGROUND
  The study was approved by the local ethics committee (KEK-ZH-Nr. 2011-0034) and registered with ClinicalTrials.gov (NCT01516775).
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Steinwiesstrasse 75, Zurich CH-8032, Switzerland alexander.schmidt@kispi.uzh.ch.
authors.forename: A R
authors.initials: AR
authors.lastname: Schmidt
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Steinwiesstrasse 75, Zurich CH-8032, Switzerland.
authors.forename: P
authors.initials: P
authors.lastname: Buehler
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Steinwiesstrasse 75, Zurich CH-8032, Switzerland.
authors.forename: L
authors.initials: L
authors.lastname: Seglias
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Steinwiesstrasse 75, Zurich CH-8032, Switzerland.
authors.forename: T
authors.initials: T
authors.lastname: Stark
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Steinwiesstrasse 75, Zurich CH-8032, Switzerland.
authors.forename: B
authors.initials: B
authors.lastname: Brotschi
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Steinwiesstrasse 75, Zurich CH-8032, Switzerland.
authors.forename: T
authors.initials: T
authors.lastname: Renner
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Steinwiesstrasse 75, Zurich CH-8032, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Sabandal
authors.affiliation: Department of Psychiatry and Psychotherapy, University Hospital, Zurich, Switzerland.
authors.forename: R
authors.initials: R
authors.lastname: Klaghofer
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Steinwiesstrasse 75, Zurich CH-8032, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Weiss
authors.affiliation: Department of Anaesthesia, University Children's Hospital, Steinwiesstrasse 75, Zurich CH-8032, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Schmitz
mesh_terms: D000293:Adolescent; D000768:Anesthesia, General; D001628:Beverages; D002648:Child; D002675:Child, Preschool; D004326:Drinking; D017558:Elective Surgical Procedures; D005215:Fasting / Q000378:metabolism*; D005260:Female; D005745:Gastric Acidity Determination; D005750:Gastric Juice / Q000378:metabolism*; D005766:Gastrointestinal Contents / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007223:Infant; D008297:Male; D011300:Preoperative Care / Q000379:methods*; D011446:Prospective Studies; D013997:Time Factors
keywords: anaesthesia; anaesthesia recovery period; clinical trial