title: Comparison of the size 3 and size 4 ProSeal™ laryngeal mask airway in anesthetized, non-paralyzed women: a randomized controlled trial.
abstract: OBJECTIVE
  Based on experimental results, various authors have advocated a size 4 ProSeal™ laryngeal mask airway (PLMA) in preference to a size 3 PLMA for women given a neuromuscular blocking agent because the larger size provided a better airway seal. However, spontaneously breathing patients may be ventilated adequately with a lower seal pressure than that needed for mechanical ventilation. Therefore, a smaller size might be preferable as its reduced bulk possibly induces less mucosal damage in non-paralyzed patients.
  
  
  METHODS
  A total of 152 females undergoing general anesthesia for short outpatient gynecological surgeries were randomly allocated in equal numbers to insertion of a size 3 or 4 PLMA. The insertion time, success rate, seal pressure, hemodynamic variables, and complications, such as blood staining and sore throat, were evaluated.
  
  
  RESULTS
  The incidence of blood staining was lower with the size 3 PLMA compared to the size 4 PLMA (18 vs. 36 %; P = 0.028). Compared with the size 3 LMA, the size 4 PLMA resulted in higher fluctuations in both blood pressure (P = 0.003) and heart rate (P = 0.01). The insertion time was shorter with the size 3 PLMA (9 vs. 16 s; P < 0.001). The airway seal pressure with the size 3 PLMA, although lower than that of the size 4 PLMA (23 vs. 28 cmH2O; P = 0.001), was sufficient for spontaneous ventilation.
  
  
  CONCLUSIONS
  Due to the reduced incidence of mucosal injury and greater hemodynamic stability, the size 3 PLMA may be preferable to the size 4 PLMA for non-paralyzed females.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul St. Mary's Hospital, Catholic University of Korea, Seocho-Go, Seoul, South Korea.
authors.forename: Mi-Hyun
authors.initials: MH
authors.lastname: Kim
authors.forename: Jung-Won
authors.initials: JW
authors.lastname: Hwang
authors.forename: Eun-Sung
authors.initials: ES
authors.lastname: Kim
authors.forename: Sung-Hee
authors.initials: SH
authors.lastname: Han
authors.forename: Young-Tae
authors.initials: YT
authors.lastname: Jeon
authors.forename: Sun-Mi
authors.initials: SM
authors.lastname: Lee
mesh_terms: D000328:Adult; D000768:Anesthesia, General / Q000295:instrumentation*; D005260:Female; D013509:Gynecologic Surgical Procedures; D006439:Hemodynamics; D006470:Hemorrhage / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D017214:Laryngeal Masks / Q000009:adverse effects; D007820:Laryngeal Mucosa / Q000293:injuries / Q000473:pathology; D008875:Middle Aged; D010612:Pharyngitis / Q000453:epidemiology; D011183:Postoperative Complications / Q000453:epidemiology; D016896:Treatment Outcome