A Comparison of Different Ventilation Strategies in Children Using the Proseal™ Laryngeal Mask Airway

• Differences in respiratory rates between spontaneous ventilation and pressure support ventilation groups. [ Time Frame: 6 months ] [ Designated as safety issue: No ]
• Mean values of respiratory rate compared between the spontaneous ventilation and pressure control ventilation groups. [ Time Frame: 6 months ] [ Designated as safety issue: No ]
• Mean values of respiratory rate compared between pressure support ventilation and pressure control ventilation groups. [ Time Frame: 6 months ] [ Designated as safety issue: No ]

The purpose of this research study is to compare difference between breathing by oneself or with the partial help from an anesthesia machine in children under general anesthesia.

The laryngeal mask airway (LMA) is a breathing device that sits above the vocal cords and allows the patient to breathe in and out adequately under general anesthesia (GA). The ProSeal™ LMA (PLMA™) is a specialized type of LMA with a design that permits the delivery of higher pressures to help the patient breathe in and out (ventilate) and also contains a channel to suction the stomach.

Children under GA may breathe through a PLMA in different ways. Spontaneous ventilation consists of the children breathing on their own through a PLMA™. Pressure support ventilation allows the patient to breathe on their own with additional help from the anesthesia machine. Pressure control ventilation allows the patient to breathe with the help of an anesthesia machine.

A child undergoing surgery requires a deep level of general anesthesia which negatively affects their ability to ventilate. Thus, children may not breathe in oxygen and carbon dioxide out adequately at this level of anesthesia and it may be beneficial to provide some level of support to enhance carbon dioxide exchange and to avoid hypoventilation.

This study will attempt to determine whether pressure support ventilation improves ventilation in children undergoing outpatient surgery.

• Procedure: Spontaneous ventilation
  The patient will breathe spontaneously (on their own)while under general anesthesia throughout the duration of the surgery.
• Procedure: Pressure support Ventilation
  The patient will breathe on their own and with a little assistance from the anesthesia machine while under general anesthesia throughout the duration of the surgery.
• Procedure: Pressure control ventilation
  The patient's ventilation will be completely supported by the anesthesia machine while under general anesthesia throughout the duration of the surgery.

• Experimental: Spontaneous ventilation
  Intervention: Procedure: Spontaneous ventilation
• Experimental: Pressure support ventilation
  Intervention: Procedure: Pressure support Ventilation
• Active Comparator: Pressure control ventilation
  Intervention: Procedure: Pressure control ventilation

• Brain AI, McGhee TD, McAteer EJ, Thomas A, Abu-Saad MA, Bushman JA. The laryngeal mask airway. Development and preliminary trials of a new type of airway. Anaesthesia. 1985 Apr;40(4):356-61.
• Mason DG, Bingham RM. The laryngeal mask airway in children. Anaesthesia. 1990 Sep;45(9):760-3.
• Shimbori H, Ono K, Miwa T, Morimura N, Noguchi M, Hiroki K. Comparison of the LMA-ProSeal and LMA-Classic in children. Br J Anaesth. 2004 Oct;93(4):528-31. Epub 2004 Aug 6.
• Lardner DR, Cox RG, Ewen A, Dickinson D. [Comparison of laryngeal mask airway (LMA)- Proseal and the LMA-Classic in ventilated children receiving neuromuscular blockade] Can J Anaesth. 2008 Jan;55(1):29-35. Erratum in: Can J Anaesth. 2008 May;55(5):321.
• Bagshaw O. The size 1.5 laryngeal mask airway (LMA) in paediatric anaesthetic practice. Paediatr Anaesth. 2002 Jun;12(5):420-3.
• Licina A, Chambers NA, Hullett B, Erb TO, von Ungern-Sternberg BS. Lower cuff pressures improve the seal of pediatric laryngeal mask airways. Paediatr Anaesth. 2008 Oct;18(10):952-6. Epub 2008 Jul 21.
• Wheeler M. ProSeal laryngeal mask airway in 120 pediatric surgical patients: a prospective evaluation of characteristics and performance. Paediatr Anaesth. 2006 Mar;16(3):297-301.
• Goldmann K, Jakob C. A randomized crossover comparison of the size 2 1/2 laryngeal mask airway ProSeal versus laryngeal mask airway-Classic in pediatric patients. Anesth Analg. 2005 Jun;100(6):1605-10.
• Lopez-Gil M, Brimacombe J, Alvarez M. Safety and efficacy of the laryngeal mask airway. A prospective survey of 1400 children. Anaesthesia. 1996 Oct;51(10):969-72.
• Keidan I, Berkenstadt H, Segal E, Perel A. Pressure versus volume-controlled ventilation with a laryngeal mask airway in paediatric patients. Paediatr Anaesth. 2001 Nov;11(6):691-4.
• Lopéz Gil ML, Brimacombe J, Clar B. Sevoflurane versus propofol for induction and maintenance of anaesthesia with the laryngeal mask airway in children. Paediatr Anaesth. 1999;9(6):485-90.
• Garcia-Fernandez J, Tusman G, Suarez-Sipmann F, Llorens J, Soro M, Belda JF. Programming pressure support ventilation in pediatric patients in ambulatory surgery with a laryngeal mask airway. Anesth Analg. 2007 Dec;105(6):1585-91, table of contents.

Inclusion Criteria:

• ASA physical classification 1,2 (Healthy or relatively healthy children)
• Subjects scheduled for outpatient surgical procedures.
• Surgical procedure anticipated to be < 90 minutes
• Subject weight of ≤ 20 kg (44 lbs)
• Subject age of 12 months to 5 years (inclusive)

Exclusion Criteria:

• Inpatient
• ASA physical classification of 3, 4 or E (sick children)
• Risk of aspiration
• Subjects with malignant hyperthermia or family history of malignant hyperthermia
• Subjects with tracheostomies