title: Negative pressure ventilation vs external high-frequency oscillation during rigid bronchoscopy. A controlled randomized trial.
abstract: OBJECTIVE
  To compare the effectiveness of two modalities of external ventilation during rigid bronchoscopy: intermittent negative pressure ventilation (INPV) and external high-frequency oscillation (EHFO).
  
  
  METHODS
  Prospective, controlled, randomized, nonblinded study.
  
  
  METHODS
  University-affiliated hospital.
  
  
  METHODS
  Seventy patients undergoing interventional rigid bronchoscopy for tracheobronchial lesions were enrolled into the study.
  
  
  METHODS
  Mechanical ventilation was performed by INPV or EHFO. When pulse oximetry was < 90%, manually assisted ventilation was delivered.
  
  
  RESULTS
  Arterial blood gases were sampled preoperatively and intraoperatively. Most patients in both groups had normal intraoperative PaCO(2) (mean, 43. 6 +/- 11.8 mm Hg under EHFO and 37.4 +/- 8.2 mm Hg under INPV; p = 0.012), and acidemia occurred in 9 of 35 patients of EHFO group and in 2 of 35 patients of INPV group (p = 0.049). Hypercapnia (PaCO(2) > 50 mm Hg) was observed in 10 patients under EHFO and in 2 with INPV (p = 0.026). Intraoperative mean PaO(2) was similar (101.4 +/- 52.9 mm Hg with EHFO and 124.2 +/- 50.3 mm Hg with INPV; p = 0.07), but O(2) supply was different (3.5 +/- 2.3 L/min during INPV and 8.5 +/- 6.2 L/min during EHFO; p < 0.001). Intraoperative hypoxemia (PaO(2) < 60 mm Hg) occurred in five patients with EHFO and two with INPV (p = 0.426). Three EHFO patients required manually assisted ventilation (mean, 0.2 +/- 0.9), but no INPV patient did (p = 0.142).
  
  
  CONCLUSIONS
  External negative pressure ventilation appears to be a suitable choice during rigid bronchoscopy: both EHFO and INPV ensure effective ventilation and comfortable operating conditions in the majority of patients. Some patients may receive inadequate ventilation with EHFO, developing respiratory acidosis and requiring manually assisted ventilation. In comparison with INPV, EHFO requires a higher fraction of inspired oxygen.
authors.affiliation: Department of Anesthesia and Intensive, University of Brescia, Italy. newpoli@tin.it
authors.forename: G
authors.initials: G
authors.lastname: Natalini
authors.forename: S
authors.initials: S
authors.lastname: Cavaliere
authors.forename: V
authors.initials: V
authors.lastname: Seramondi
authors.forename: P
authors.initials: P
authors.lastname: Foccoli
authors.forename: M
authors.initials: M
authors.lastname: Vitacca
authors.forename: N
authors.initials: N
authors.lastname: Ambrosino
authors.forename: A
authors.initials: A
authors.lastname: Candiani
mesh_terms: D000328:Adult; D000368:Aged; D001984:Bronchial Neoplasms / Q000628:therapy*; D001999:Bronchoscopy; D005260:Female; D006612:High-Frequency Ventilation; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000379:methods*; D014134:Tracheal Neoplasms / Q000628:therapy*; D015919:Ventilators, Negative-Pressure