title: Impact of nasogastric tubes on swallowing physiology in older, healthy subjects: A randomized controlled crossover trial.
abstract: OBJECTIVE
  The presence of a nasogastric tube (NGT) affects swallowing physiology but not function in healthy young adults. The swallowing mechanism changes with increasing age, therefore the impact of a NGT on swallowing in elderly individuals is likely to be different but is not yet known. The aims of this study were to determine the effects of NGTs of different diameter on (1) airway penetration-aspiration, (2) pharyngeal residue, and (3) pharyngeal transit, in older healthy subjects.
  
  
  METHODS
  Randomized controlled crossover design. Healthy elderly volunteers underwent 3 modified barium swallow studies in which multiple diet and fluid consistencies were swallowed under the following conditions: (A) no NGT (control), (B) fine bore NGT, and (C) wide bore NGT. The control condition was assessed first to establish baseline swallowing function, then NGT order was randomly allocated.
  
  
  RESULTS
  Of the 15 volunteers (median age 65 years, range 60-81) complete data sets were obtained for 9 (4 with allocation order ABC; 5 with ACB). Wide bore NGT data could not be obtained for 6 volunteers mainly due to tube intolerance. The presence of a NGT was associated with: (i) an increase in airway penetration-aspiration (fine bore NGT with serial liquid swallows and puree) (p < 0.01); (ii) increased pharyngeal residue (p < 0.05) in the pyriform sinus (fine bore NGT with puree); and in the valleculae (both fine and wide bore NGT with soft solids); and (iii) an increase in pharyngeal transit duration regardless of consistency (p < 0.01), with longest swallowing durations with the widest tube.
  
  
  CONCLUSIONS
  NGT presence increases airway penetration-aspiration, pharyngeal residue and prolongs transit through the pharynx in older healthy individuals. Consideration of NGT impact on swallowing during concurrent oral and enteral feeding is recommended, with further systematic investigation required in elderly patients recovering from critical illness. Clinical trial registry Australia & New Zealand Clinical Trials Registry (ACTRN12613000577718).
authors.affiliation: Intensive Care Unit, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia 5000, Australia; The University of Queensland, School of Health & Rehabilitation Sciences, St Lucia, Queensland 4072, Australia. Electronic address: lee.pryor@health.sa.gov.au.
authors.forename: Lee N
authors.initials: LN
authors.lastname: Pryor
authors.affiliation: The University of Queensland, School of Health & Rehabilitation Sciences, St Lucia, Queensland 4072, Australia; Centre for Functioning & Health Research (CFAHR), Buranda, Queensland 4102, Australia. Electronic address: liz.ward@uq.edu.au.
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Ward
authors.affiliation: The Prince Charles Hospital, Metro North Hospital and Health Service, Chermside, Queensland 4032, Australia; Behavioural Basis of Health Program, Griffith Health Institute, Griffith University, Mount Gravatt, Queensland 4122, Australia. Electronic address: petrea.cornwell@health.qld.gov.au.
authors.forename: Petrea L
authors.initials: PL
authors.lastname: Cornwell
authors.affiliation: Intensive Care Unit, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia 5000, Australia; Discipline of Acute Care Medicine, The University of Adelaide, Adelaide, South Australia 5000, Australia. Electronic address: stephanie.o'connor@health.sa.gov.au.
authors.forename: Stephanie N
authors.initials: SN
authors.lastname: O'Connor
authors.affiliation: Intensive Care Unit, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia 5000, Australia; Discipline of Acute Care Medicine, The University of Adelaide, Adelaide, South Australia 5000, Australia. Electronic address: mark.finnis@adelaide.edu.au.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Finnis
authors.affiliation: Intensive Care Unit, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia 5000, Australia; Discipline of Acute Care Medicine, The University of Adelaide, Adelaide, South Australia 5000, Australia. Electronic address: marianne.chapman@health.sa.gov.au.
authors.forename: Marianne J
authors.initials: MJ
authors.lastname: Chapman
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018592:Cross-Over Studies; D003679:Deglutition / Q000502:physiology*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007441:Intubation, Gastrointestinal / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010614:Pharynx / Q000378:metabolism; D013997:Time Factors
keywords: Aspiration; Elderly; Enteral nutrition; Nasogastric tube; Supplemental feeding; Swallowing