title: Tracheal amylase dosage as a marker for microaspiration: a pilot study.
abstract: BACKGROUND
  Devices that limit microaspiration through the cuffs of endotracheal tubes could help prevent ventilator-associated pneumonia (VAP). The amount of tracheal microaspirations could be a relevant study endpoint. The aim of our study was to assess whether amylase measured in tracheal secretions constituted a relevant marker for microaspiration.
  
  
  METHODS
  Twenty-six patients, intubated for at least 48 h and supplied with a subglottic secretion-suctioning device, constituted a group with a high risk of microaspiration. Twelve non-ventilated patients that required a bronchoscopy procedure constituted a group with a low risk of microaspiration (the control group). Tracheal (T) amylase was compared between the groups. In the intubated group, a series of oral (O), subglottic (Sg) and tracheal (T) suction samples were collected and T/O, T/Sg, Sg/O amylase ratios were determined.
  
  
  RESULTS
  Amylase was measured in 277 (89 Sg, 96 B, 92 T) samples from the intubated group and in 12 T samples from the control group. Tracheal amylase was lower in the control group than the intubated group (191 [10-917] vs. 6661 [2774-19,358] IU/L, P<0.001). Amylase gradually increased from tracheal (6661 [2774-19,358] IU/L), to subglottic (130,750 [55,257-157,717] IU/L), to oral samples (307,606 [200,725-461,300] IU/L), resulting in a median 5.5% T/O ratio. In a subset of intubated patients, T amylase samples were assessed in two different laboratories, and gave reproducible results.
  
  
  CONCLUSIONS
  Tracheal amylase was easy to collect, transport, and measure. The T/O amylase ratio is a first step towards quantifying oropharyngeal to tracheal microaspiration in mechanically-ventilated patients.
authors: Medical Intensive Care Unit, CHU Bordeaux, Bordeaux, France - alexandre.boyer@chu-bordeaux.fr.
authors: B
authors: B
authors: Filloux
authors: A
authors: A
authors: Bedel
authors: S
authors: S
authors: Nseir
authors: J
authors: J
authors: Mathiaux
authors: B
authors: B
authors: Amadéo
authors: B
authors: B
authors: Clouzeau
authors: J
authors: J
authors: Pillot
authors: T
authors: T
authors: Saghi
authors: F
authors: F
authors: Vargas
authors: G
authors: G
authors: Hilbert
authors: D
authors: D
authors: Gruson
authors: A
authors: A
authors: Boyer
mesh_terms: D000328:Adult; D000368:Aged; D000681:Amylases / Q000032:analysis*; D015415:Biomarkers / Q000032:analysis*; D001999:Bronchoscopy; D023381:Endpoint Determination; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal; D008297:Male; D008875:Middle Aged; D011015:Pneumonia, Aspiration / Q000201:enzymology*; D053717:Pneumonia, Ventilator-Associated / Q000517:prevention & control; D011446:Prospective Studies; D012372:ROC Curve; D013396:Suction; D014132:Trachea / Q000201:enzymology*
chemical_list: D015415:Biomarkers; D000681:Amylases