title: Pulmonary aspiration of gastric contents in patients receiving mechanical ventilation: the effect of body position.
abstract: OBJECTIVE
  To determine if the semirecumbent position (45-degree angle) decreases aspiration of gastric contents to the airways in intubated and mechanically ventilated patients.
  
  
  METHODS
  A randomized, two-period crossover trial.
  
  
  METHODS
  Respiratory intensive care unit.
  
  
  METHODS
  Nineteen patients requiring intubation and mechanical ventilation.
  
  
  METHODS
  Patients were studied in the supine and semirecumbent positions on two separate days.
  
  
  METHODS
  After technetium (Tc)-99m sulphur colloid labeling of gastric contents, sequential radioactive counts in endobronchial secretions were measured at 30-minute intervals over a 5-hour period. Samples of endobronchial secretions, gastric juice, and pharyngeal contents were obtained for qualitative bacterial cultures.
  
  
  RESULTS
  Mean radioactive counts in endobronchial secretions were higher in samples obtained while patients were in the supine position than in those obtained while patients were in the semirecumbent position (4154 cpm compared with 954 cpm; P = 0.036). Moreover, the aspiration pattern was time-dependent for each position: For the supine position, radioactivity was 298 cpm at 30 min and 2592 cpm at 300 min (P = 0.013); for the semirecumbent position, radioactivity was 103 cpm at 30 min and 216 cpm at 300 min (P = 0.04). The same microorganisms were isolated from stomach, pharynx, and endobronchial samples in 32% of studies done while patients were semirecumbent and in 68% of studies done while patients were in the supine position.
  
  
  CONCLUSIONS
  We conclude that the supine position and length of time the patient is kept in this position are potential risk factors for aspiration of gastric contents. Elevating the head of the bed for patients who can tolerate the semirecumbent position may be a simple, no-cost prophylactic measure.
authors.affiliation: Universitat de Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Torres
authors.forename: J
authors.initials: J
authors.lastname: Serra-Batlles
authors.forename: E
authors.initials: E
authors.lastname: Ros
authors.forename: C
authors.initials: C
authors.lastname: Piera
authors.forename: J
authors.initials: J
authors.lastname: Puig de la Bellacasa
authors.forename: A
authors.initials: A
authors.lastname: Cobos
authors.forename: F
authors.initials: F
authors.lastname: Lomeña
authors.forename: R
authors.initials: R
authors.lastname: Rodríguez-Roisin
mesh_terms: D005260:Female; D005750:Gastric Juice / Q000382:microbiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010614:Pharynx / Q000382:microbiology; D011015:Pneumonia, Aspiration / Q000209:etiology* / Q000517:prevention & control*; D011187:Posture; D012121:Respiration, Artificial / Q000009:adverse effects* / Q000379:methods*; D012307:Risk Factors; D016683:Supine Position; D013671:Technetium Tc 99m Sulfur Colloid; D014132:Trachea / Q000382:microbiology
chemical_list: D013671:Technetium Tc 99m Sulfur Colloid