Study Methods

- Population of study: These prospective randomized controlled clinical trials will be
conducted at Aswan University hospital on 375 obese patients:

- Study location: This is a prospective study that will be conducted at Aswan
University Hospital. Fit Patients who will undergo surgeries with BMI >30 Age:
between 18 and 60. Both genders. ASA I/II patients.

- Exclusion criteria:

Morbid obese patients with BMI > 40 Having facial anomalies. Patients with pre-existing
diaphragmatic or respiratory disorders ASA III/IV.

- Methodology in details: A computer-generated randomization list will be used to
randomize consented study participants on a 1:1:1 ratio to compare hook method versus E/C
versus T/E technique.

The patients will be randomly assigned to 3 groups

- Group 1 hook method: Providers will be trained and standardized in the new hook
technique for single-hand ventilation

- Group 2 (E/C): Providers will use the thenar eminence-chin lift technique

- Group 3 (T/E): Providers will use the thenar eminence-encircling technique

Preoperative:

After taking consent from the patients included in the study, all patients will receive
pre-anesthesia airway evaluation before entering the operation room, and their
interincisor distance, thyromental distance and Mallampati classification will be
measured and recorded. Each patient will be asked to fast for at least 8 h and will be
given no premedicationnoninvasive blood pressure, pulse oximetry (SpO2), end-tidal CO2
estimation (PETCO2), anesthetic agent analyzer will be attached to all patients.

Intraoperative:

After 3 min of preoxygenation, general anesthesia will be induced using 1-2 μg/kg
fentanyl, 2-3 mg/kg propofol, and 0.6-1.2 mg/ kg rocuronium followed by different
desirable face mask-ventilation after full relaxation with a mixture of 100% oxygen and
2% sevoflurane and ventilation parameters will be setted up, volume control ventilation
mode, tidal volume 8ml/kg ideal body weight, RR 12. PEEP 5, fio2 100 %. Antisialogogues
will be used before instrumentation of airway (atropine 0.5-1 mg). Oral airway will be
inserted according to measurement from angle of the mouth to angle of the mandible to
facilitate the ventilation and make it symmetrical.

Technique:

Two commonly used traditional methods for single-hand ventilation include:

1. E-C Clamp Technique: The E-C clamp technique involves forming a "C" with the thumb
and index finger around the mask while the remaining fingers form an "E" to lift the
mandible. This technique aims to provide a good seal while opening the airway.

2. T-E Technique: The T-E technique is a variation where the thumb and index finger
form a "T" over the mask while the other fingers provide chin lift and jaw thrust.

This method is designed to optimize airway patency and mask seal. While these
techniques are widely taught and practiced, they often fall short in obese patients
due to the difficulty in maintaining an adequate seal and achieving sufficient
ventilation pressures. Complications such as hypoxemia and gastric insufflation are
more common in this population.

3. The Hook Technique is a novel method for single-hand ventilation that has shown
promise in preliminary studies. This technique involves a unique hand positioning
that aims to improve mask seal and ventilation efficacy, particularly in patients
with challenging airway anatomy. In Hook Technique using the thumb and index finger
to form a hook around the mask, creating a more secure and adjustable seal and
utilizing the remaining fingers to apply consistent mandibular lift, enhancing
airway patency.

- Does the research involve? Human participants Biological samples/Tissues
Identifiable private data/Information

- Type of consent of study participants:

Written consent No consent needed (Please justify) Oral consen

- Potential risks:

1. Hypoventilation

2. Desaturation

3. Hypercarbia

Confidentiality of data:

Ensure patient privacy, confidentiality of data throughout the study and
Informed consent: Ensure participants fully understand the study and provide
informed consent before participation. 9. Study outcomes

The following outcomes will be recorded:

Primary Outcome Measures 1. Success Rate of Ventilation: Definition: The
primary measure of success will be defined as achieving effective ventilation
within a set timeframe. Effective ventilation is indicated by:

1. Visible and adequate chest rise and fall.

2. chest expansion by ultra-sounded guided diaphragmatic excursion at certain
time 30, 60, 90, 120 second.

3. End tidal Co2 in Capnography at certain time 30, 60, 90, 120 second. prior
to surgery. On arrival at the operating room (OR), five-lead ECG, d)
Oxygen saturation (SpO2) levels reaching ≥ 95% within 2 minutes of
applying the ventilation technique.

e) Exhaled Tidal Volume at certain time 30, 60, 90, 120 second. f) Peak
Inspiratory Pressure (PIP).

Measurement:

• Chest Rise and Fall: This will be visually assessed by an independent
observer.

evaluation the techniques based on the chest expansion score from 1 to 4. To
evaluate Chest Rising in the studied patients, by visual method, patients were
categorized into four groups: the amount of chest rising in group one was
between 0 and 25% (score 1), 25-50% in group two (score 2), 50-75% in group
three (score 3) and 75-100% in group four (score 4). Patients in group one and
two considered to have unsuccessful ventilation due to lack in chest rise, and
in groups three and four, the ventilation was considered successful •
Ultra-sounded guided diaphragmatic excursion: It will be considered successful
ventilation if Diaphragmatic excursion more than 2 cm and will be considered
ventilation failure if less than 2 cm Technique of Diaphragmatic Assessment

a) Equipment: using ultrasound machine (Mindray DP 2200plus). use a low
-frequency convex ultrasound probe (6-15 MHz) for diaphragmatic imaging.
connect the probe to ultrasound machine with appropriate software for image
acquisition and analysis. b) Procedure: position the patient in semi-recumbent
or supine position. Apply ultrasound Gel to the skin overlying the diaphragm in
the subcostal area. place the ultrasound probe in the subcostal region to
obtain the longitudinal view of the diaphragm. Adjust the ultrasound settings
for optimal image quality, including gain, depth, and focus. Record both B-mode
and M-mode images during face mask ventilation. Record real-time images during
various respiratory phases. Measure excursion as the difference in
diaphragmatic position between inspiration and expiration.

- Oxygen Saturation: SpO2 levels will be continuously monitored using a
pulse oximeter, with readings recorded at baseline (before ventilation)
and at regular intervals (every 15 seconds) until effective ventilation is
achieved or the 2-minute mark is reached.

- Measurement of Exhaled Tidal Volume: Determine if the Hook Technique
provides superior tidal volume (mL/kg of predicted body weight) compared
to the E-C and T-E techniques within the first 2 minutes of ventilation
and will be consider successful ventilation if exhaled tidal volume more
than 6 ml per kg and failure if less than 6 ml per kg

- Peak Inspiratory Pressure (PIP): Compare the peak inspiratory pressures
generated during ventilation with each technique and will be consider
failure of ventilation if more than 30 Lower PIP for a given tidal volume
indicates more efficient ventilation, which is particularly important in
obese patients who often require higher pressures due to increased airway
resistance Secondary Outcome Measures

1. Time to Achieve Effective Ventilation:

Definition: The time taken from the initiation of the ventilation technique to
the point at which effective ventilation is confirmed.

Measurement:

• The stopwatch will start as soon as the anesthesiologist initiates the
ventilation technique.

• The time will be stopped when the criteria for effective ventilation (chest
rise and fall, SpO2 ≥ 95%) are met.

• This measure provides an indication of the efficiency of each technique in
rapidly achieving effective ventilation.

2. Rate of Ventilation Attempts:

Definition: The number of attempts needed to achieve effective ventilation.

Measurement:

Each attempt is defined as a discrete application of the ventilation technique.
Multiple attempts within the 2-minute timeframe will be recorded and analyzed.
The number of attempts required to achieve successful ventilation will be
compared across the three techniques to assess reliability and ease of
achieving effective ventilation.

3. Incidence of Ventilation Failure:

Definition: Failure to achieve effective ventilation within the 2-minute
timeframe.

Measurement:

Any cases where effective ventilation is not achieved within 2 minutes will be
documented.

The reasons for failure (e.g., difficulty in mask seal, inadequate chest rise)
will be recorded and analyzed to understand the limitations of each technique.

4. Complications:

Document any airway trauma, hypoxemia episodes (Defined as SpO2 dropping below
90% at any time during the ventilation attempts. The frequency and duration of
hypoxemia episodes will be recorded.), or other adverse events. Incidents of
trauma such as lip lacerations, dental injury, or soft tissue damage will be
documented. The severity and type of airway trauma will be recorded and
compared among the three techniques.

5. Ease of use:

Assessed through a standardized provider questionnaire rating comfort and ease
on a Likert scale and the provider will be asked to rate the used technique of
mask ventilation from easy to neutral to fatigue on using 10.Sample size
Primary Outcome Measure: Success Rate of Ventilation Definition: Achieving
effective chest rise and SpO2 ≥ 95% within 2 minutes of initiating ventilation.
Primary Comparison: Success rates of the hook technique versus E/C and T/E
techniques.

Assumptions for Sample Size Calculation:

Baseline Success Rate (E/C and T/E Techniques): Based on previous studies and
clinical experience, assume a success rate of approximately 70% for traditional
techniques in obese patients. Expected Success Rate (Hook Technique):
Hypothesized to be higher, for instance, around 85%. Significance Level (α):
0.05 (two-sided) Power (1 - β): 0.80 (80% power) Effect Size: The difference in
success rates (15%). Total Sample Size: 375 patients, approximately 125
patients per group (Hook, E/C, T/E).Study Blinding 1. Blinding of Outcome
Assessors:

• Outcome assessors and data analysts will be blinded to the used technique and
the provider will be blinded to effective ventilation parameters to reduce bias
in the evaluation of outcomes.

• Blinded assessors will perform data collection related to primary and
secondary outcome measures, such as chest rising, diaphragmatic excursion,
exhaled tidal volume, PIP, SpO₂ levels, and provider feedback. 2. Blinding of
Participants and Providers:

- Full blinding of participants and providers is not feasible due to the
nature of the intervention.

However, efforts will be made to minimize bias by standardizing procedures and
training.

- Providers will be trained to perform all three techniques to reduce
performance bias.

11. Statistical analysis Data analysis will be conducted using SPSS
software version 22. We will collect and analyze demographic data,
reporting success rates as frequencies and mean ± standard deviation.

Primary Analysis:

We will compare the success rates using chi-square tests.

Secondary Analysis:

We will compare time to effective ventilation using ANOVA or Kruskal-Wallis
tests.

We will analyze ease of use ratings and complication rates using appropriate
statistical tests.

Multivariate Analysis:

We will djust for potential confounders such as age, sex, and BMI category.

Ethical Considerations:

Informed Consent: All participants will provide written informed consent.
Ethical Approval: The study will be approved by the institutional review board
(IRB).

Safety Monitoring: A data and safety monitoring board (DSMB) will oversee the
trial.

12. Source of funding: Non. 13.Time plan:

- When to start? July 2024

- When expected to finish? March 202514.References:

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