title: A comparison of the cuffed oropharyngeal airway (COPA) with the laryngeal mask airway (LMA) during manually controlled positive pressure ventilation.
abstract: OBJECTIVE
  To examine the cuffed oropharyngeal airway (COPA) during positive pressure ventilation (PPV) and to compare its reliability and efficacy with the laryngeal mask airway (LMA).
  
  
  METHODS
  Prospective, randomized, controlled trial.
  
  
  METHODS
  University Hospital.
  
  
  METHODS
  60 adult ASA physical status I and II patients scheduled for urologic surgery.
  
  
  METHODS
  Patients were randomly assigned to be ventilated with a COPA (n = 33) or a LMA (n = 27) during a standardized anesthetic procedure. Following preoxygenation and induction with alfentanil and propofol, the respective airways were inserted. Patients were ventilated manually with the reservoir bag of the anesthesia respirator. Inspiratory airway pressure was limited to 20 cm H2O, and the target tidal volume was 7 ml/kg. Respiratory rate was adjusted to achieve an end-tidal pressure of carbon dioxide of 35 mmHg. Anesthesia was maintained with propofol, nitrous oxide in oxygen, and alfentanil, as appropriate.
  
  
  RESULTS
  We evaluated ease of insertion (nominal scale: easy, moderate, difficult, or impossible) and recorded the number of maneuvers performed during insertion until an airtight seal of the airway was achieved. Reliability for "hands free" ventilation--defined as ventilation without the need to further augment the position of the airway device manually--was determined (nominal scale: adequate ventilation, adequate ventilation with manual assistance, and inadequate ventilation leading to airway change). Ventilation and oxygenation parameters were derived from the anesthesia respirator and a capillary blood gas sample, respectively. The incidence of laryngopharyngeal discomfort and the amount of salivation were assessed by nominal scales. The COPA was easier to insert than the LMA (p < 0.001), but more positional maneuvers (p < 0.001) were necessary with this device. "Hands free" ventilation was achieved less often with the COPA (p < 0.02). Ventilation and oxygenation were comparable with both devices. The COPA was associated with less salivation (p < 0.01) and laryngopharyngeal discomfort (p < 0.05) than the LMA.
  
  
  CONCLUSIONS
  Although effective ventilation can be accomplished with both devices, the LMA is more reliable for "hands free" ventilation than the COPA. The lower incidence of laryngopharyngeal discomfort and salivation with the COPA may be beneficial for patients at risk for developing laryngospasm.
authors.affiliation: Klinik für Anaesthesiologie, Medizinische Universität zu Luebeck, Germany. Heringlake@t-online.de
authors.forename: M
authors.initials: M
authors.lastname: Heringlake
authors.forename: V
authors.initials: V
authors.lastname: Doerges
authors.forename: H
authors.initials: H
authors.lastname: Ocker
authors.forename: P
authors.initials: P
authors.lastname: Schmucker
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015760:Alfentanil / Q000008:administration & dosage; D018686:Anesthetics, Intravenous / Q000008:administration & dosage; D002245:Carbon Dioxide / Q000097:blood / Q000378:metabolism; D005260:Female; D006801:Humans; D007431:Intraoperative Complications; D007442:Intubation, Intratracheal / Q000295:instrumentation*; D017214:Laryngeal Masks; D008297:Male; D008875:Middle Aged; D009960:Oropharynx; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology; D010146:Pain / Q000209:etiology; D011175:Positive-Pressure Respiration; D015742:Propofol / Q000008:administration & dosage; D011446:Prospective Studies; D015203:Reproducibility of Results; D012119:Respiration; D012472:Salivation; D013990:Tidal Volume / Q000502:physiology; D013520:Urologic Surgical Procedures
chemical_list: D018686:Anesthetics, Intravenous; D002245:Carbon Dioxide; D015760:Alfentanil; D010100:Oxygen; D015742:Propofol