Clinical trial NCT00592423: CPAP and Lateral Neck Rotation on Anesthetized Children
Official title: Effect of Neck Rotation and Continuous Positive Airway Pressure (CPAP) on Upper Airway Anatomy in Anesthetized Children - an MRI Study
Study type: INTERVENTIONAL
Overall status: TERMINATED
Phase: NA
Conditions: Hypoventilation
Keywords: Lateral neck rotation
Continuous Positive Airway Pressure
Lead sponsor: Children's Hospital of Philadelphia
Sponsor class: OTHER
Collaborators: name: Children's Anesthesiology Associates, Ltd.
First posted: 2008-01-14
Enrollment: 12
Sex: ALL
Maximum age (years): 5
Standard ages: CHILD
Accepts healthy volunteers: no
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: DIAGNOSTIC

Brief summary: The primary aim of this study is to determine the changes in upper airway anatomy that occur during lateral neck rotation and subsequent administration of continuous positive airway pressure (CPAP) in anesthetized, spontaneously breathing children. The hypothesis for this study is that neck rotation decreases overall upper airway volume because of constriction at the level of the larynx, and that this constriction is relieved by administration of CPAP.

Detailed description: The most commonly performed surgical procedure requiring general anesthesia in the pediatric population is myringotomy and placement of pressure equalizing tubes in the middle ear. It is performed in otherwise healthy children with chronic middle ear fluid collections and infections. In these cases, general anesthesia is accomplished by inhalation of a volatile anesthetic gas, which induces unconsciousness and analgesia for the approximately 10 minutes it takes to perform the procedure. A requirement of the procedure is lateral neck rotation by the anesthesiologist managing the airway. This enhances surgical visibility (Fig 1). However, a well-known clinical consequence of lateral neck rotation is development of upper airway obstruction with subsequent hypoxemia.1 Anesthesiologists routinely counteract this problem by placement of an oral airway device or application of CPAP, or both. Nevertheless, intervening hypoxia often necessitates temporary halting of the procedure and resumption of the neutral neck position until hypoxemia abates. This study will determine the anatomical mechanism for upper airway obstruction during lateral neck rotation and will elucidate the effects of administration of CPAP on this obstruction.

This study will use an MRI imaging technique that has been used recently at CHOP by Drs. Raanan Arens and Soroosh Mahboubi to study the three-dimensional characteristics of the upper airway in children. This methodology, which was developed at the University of Pennsylvania and CHOP, utilizes fuzzy connectedness-based automatic segmentation that allows visualization of the upper airway in a correct anatomical orientation as it relates to airflow.2,3 This technology has been successfully applied to anesthetized children without any apparent adverse effects (see IRB # 2003-2-3189).

An additional evaluable patient will be photographed during elective bronchoscopy with general anesthesia to correlate the MRI images with images visualized clinically.

Eligibility criteria: Inclusion Criteria:

1. MRI: Children requiring MRI examination with propofol sedation.
2. Bronchoscopy: Child requiring elective flexible bronchoscopy during general anesthesia. (1 child only) -

Exclusion Criteria:

1. Acute or chronic lung disease,
2. upper airway disease,
3. congestive heart failure,
4. obesity,
5. sleep apnea syndrome,
6. central nervous system disease likely to influence muscle tone,
7. any type of abnormality in head or neck anatomy, or
8. the requirement for any type of airway adjunct device (e.g., oral airway, endotracheal tube, etc.). -

Primary outcomes:
measure: This study will determine the anatomical mechanism for upper airway obstruction during lateral neck rotation and will elucidate the effects of administration of CPAP on this obstruction.
timeFrame: 10 minutes
Secondary outcomes:
Other outcomes:
Locations:
Study officials:
affiliation: Children's Hospital of Philadelphia
name: Ronald Litman, DO
role: PRINCIPAL_INVESTIGATOR
References: