Effects of One-handed and Two-handed Mask Ventilation Techniques on Global and Regional Lung Ventilation

Study Overview
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Brief Summary
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Two-handed mask ventilation has been shown to provide higher tidal volume than one-handed mask ventilation. The effects of the two techniques on respiratory mechanics during induction of general anesthesia, however, still need to be determined.

Detailed Description
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Mask positive pressure ventilation always causes the changes of respiratory mechanics such as ventral redistribution of regional ventilation, which impairs gas exchange. Two-handed mask ventilation has been shown to improve gas exchange by providing higher tidal volume than one-handed mask ventilation. We hypothesis that those higher tidal volume caused by two-handed mask ventilation would also improve the respiratory mechanics during induction of general anesthesia.

Official Title
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Department of Anesthesiology, Fudan University Shanghai Cancer Center, Fudan University, Shanghai, China.

Conditions
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Anesthesia

Intervention / Treatment
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* Other: One-handed mask ventilation
* Other: Two-handed mask ventilation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Scheduled for elective surgery with general anesthesia American Society of Anesthesiologist (ASA) physical class of I-II. Exclusion Criteria: acute and chronic respiratory disorders, including chronic obstructive pulmonary disease (COPD) and asthma; a history of lung surgery; exist risk of reflux and aspiration; patients requiring an awake intubation; facial and thoracic deformities; implants exist in the body, such as cardiac pacemakers; pregnant women.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 85 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: One-handed mask ventilation<br>For the one-handed mask ventilation, only one hand can be used to achieve the face mask seal. The left thumb and index finger form a ''C,'' providing anterior pressure over the mask, while the third, fourth, and fifth fingers form an ''E'' to lift the jaw. | Other: One-handed mask ventilation<br>* Using one-handed mask ventilation techniques during induction of general anesthesia<br>|
| Other: Two-handed mask ventilation<br>For the two-handed mask ventilation, the provider's thumb and thenar eminence of each hand are held parallel, adjacent to the mask connector, and depress each side of the mask. The second through fifth digits wrap around and elevate the mandible to draw it anteriorly into the mask establishing both a jaw-thrust and chin-lift maneuver when appropriate. | Other: Two-handed mask ventilation<br>* Using two-handed mask ventilation techniques during induction of general anesthesia<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| global inhomogeneity (GI) | EIT images will be acquired by using the EIT monitor (Drager Medical Gmbh, Lubeck, Germany). And a software package (Electrical impedance tomography diag custom software provided by Drager Medical) will be used to quantitatively analyze the EIT data. 0% = homogenous | 8 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| centre of ventilation (CoV) | EIT images will be acquired by using the EIT monitor (Drager Medical Gmbh, Lubeck, Germany). And a software package (Electrical impedance tomography diag custom software provided by Drager Medical) will be used to quantitatively analyze the EIT data. 100% = entirely dorsal. | 8 weeks | 
| regional ventilation delay (RVD) | EIT images will be acquired by using the EIT monitor (Drager Medical Gmbh, Lubeck, Germany). And a software package (Electrical impedance tomography diag custom software provided by Drager Medical) will be used to quantitatively analyze the EIT data. | 8 weeks | 
| ventilation of regional lung ( %) | EIT images will be acquired by using the EIT monitor (Drager Medical Gmbh, Lubeck, Germany). And a software package (Electrical impedance tomography diag custom software provided by Drager Medical) will be used to quantitatively analyze the EIT data. | 8 weeks | 
| Expiratory tidal volume (TV) | Expiratory tidal volume will be recorded through the anesthesia machine. | 8 weeks | 
| PaO2/FiO2 | PaO2/FiO2 will be recorded through arterial blood gas analysis. | 8 weeks |