A Comparison of Different Ventilation Strategies in Infants Using the PLMA™

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

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

Hypothesis: Infants undergoing general anesthesia with a PLMA™ will be better ventilated (improved breathing) with the help of the breathing machine versus breathing on their own.

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™ laryngeal mask airway (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.

Infants under GA may breathe through a PLMA in different ways. Spontaneous ventilation consists of the infants 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.

An infant undergoing surgery requires a deep level of general anesthesia which negatively affects their ability to ventilate. Thus, infants 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 infants undergoing outpatient surgery.

Inclusion Criteria:

1. ASA (American Society of Anesthesiologists) physical classification of 1 or 2
2. Outpatient surgical procedures
3. Surgical procedure anticipated to be < 90 minutes
4. Subject age of 1 - 11 months (inclusive)

Exclusion Criteria:

1. Inpatient- Such individuals may have underlying disease processes which puts them at an increased risk under general anesthesia for hypoventilation
2. ASA physical classification of 3, 4 or E
3. Premature infants or infants < 44 weeks post-conceptual age
4. Risk of aspiration- Intubation with an endotracheal tube may be required for general anesthesia.
5. Patients with malignant hyperthermia or family history of malignant hyperthermia- Administration of inhalational agents for general anesthesia is contraindicated.
6. Patients with tracheostomies- The individual's airway is already established and PLMA™ placement is not required.