title: The volume and pH of residual pharyngeal fluid aspirated from the TaperGuard Evac™ Endotracheal Tube following elective surgery: a prospective pilot study.
abstract: BACKGROUND
  Oropharyngeal suctioning prior to extubation aims to minimize postextubation tracheal soiling from remaining fluid. We investigated the amount and nature of any fluid remaining after such suctioning and contributing factors.
  
  
  METHODS
  ASA I - III patients undergoing elective surgery under general anesthesia with endotracheal intubation participated in this prospective observational pilot study. Following oropharyngeal suctioning immediately prior to extubation, a dedicated port of the endotracheal tube (TaperGuard Evac™ Endotracheal Tube) was aspirated. The amount and pH of residual fluid was recorded. Data collection included age, sex, body mass index, comorbidities, ASA status, procedure type and duration. The Chi-Square, Wilcoxon Rank-Sum, t-tests, and univariate regression analysis were used as appropriate.
  
  
  RESULTS
  Ninety-eight patients completed the study. The mean aspirated volume in 38 (38.8%) patients was 0.9 ± 1.3 mL and sixty patients (61.2%) had no aspirate. A body mass index of ≥ 30 kg/m2 was associated with the presence of fluid (P=0.03), and a higher volume (P=0.03). The fluid pH was 7 ± 0.81 (mean ± SD). A duration of surgery ≥ 120 minutes predicted a lower pH.
  
  
  CONCLUSIONS
  The prevalence and amount of residual fluid after oropharyngeal suctioning was low and likely clinically insignificant. A higher body mass index was associated with a higher incidence and volume of residual fluid. Longer procedure duration determined a slightly lower pH, with a mildly acidic pH range. The possibility of a lower fluid pH after prolonged surgery contributing to postoperative sore throat via mucosal irritation warrants investigation.
authors.affiliation: Department of Anesthesiology, Tufts Medical Center, Boston, MA 02111, USA. RSchumann@tuftsmedicalcenter.org
authors.forename: R
authors.initials: R
authors.lastname: Schumann
authors.forename: P
authors.initials: P
authors.lastname: Gandhi
authors.forename: K
authors.initials: K
authors.lastname: Switkowski
authors.forename: M A B
authors.initials: MA
authors.lastname: Grant
authors.forename: I
authors.initials: I
authors.lastname: Bonney
mesh_terms: D000328:Adult; D000768:Anesthesia, General; D001826:Body Fluids / Q000737:chemistry / Q000502:physiology*; D015331:Cohort Studies; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007442:Intubation, Intratracheal / Q000009:adverse effects / Q000295:instrumentation*; D008297:Male; D010614:Pharynx / Q000502:physiology*; D010865:Pilot Projects; D011446:Prospective Studies; D053120:Respiratory Aspiration / Q000209:etiology* / Q000473:pathology; D013396:Suction