Obesity
Conditions
Keywords
Preoxygenation, obesity, Pressure Support Ventilation, Positive End-Expiratory Pressure, Gastric Antrum Area
Brief summary
Obese patients are at increased risk of low oxygen levels during the induction of general anesthesia. Preoxygenation with a face mask before anesthesia is routinely used to increase oxygen reserves. This study compares three preoxygenation techniques: deep breathing alone, deep breathing with pressure-supported ventilation, and deep breathing with pressure-supported ventilation plus positive end-expiratory pressure (PEEP). The main goal of the study is to determine how quickly each technique allows patients to reach an adequate level of oxygen in the lungs. In addition, the study evaluates whether these techniques cause gastric distension, which could increase the risk of regurgitation. Gastric ultrasound is used to assess stomach size before and after preoxygenation. The results of this study will help identify the most effective and safest method of preoxygenation in obese patients undergoing elective surgery.
Interventions
PROCEDUREDeep Breathing Preoxygenation
Preoxygenation performed with deep breathing using a ventilator delivering 100% oxygen at a flow rate of 12 L/min.
PROCEDUREPressure Support Ventilation
Application of pressure support ventilation with a pressure support level of 12 cmH₂O during preoxygenation.
PROCEDUREPositive End-Expiratory Pressure
Application of positive end-expiratory pressure at a level of 6 cmH₂O during preoxygenation.
Sponsors
Pamukkale University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Intervention model description
Three-arm parallel-group randomized trial comparing deep breathing alone, deep breathing with pressure support, and deep breathing with pressure support plus PEEP for preoxygenation.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Age ≥ 18 years * Obesity * Scheduled for elective surgery under general anesthesia * Able to cooperate with deep breathing during preoxygenation
Exclusion criteria
* Hemodynamic instability * Poor cooperation * Preoperative oxygen therapy requirement * Conditions in which positive pressure ventilation may be harmful (e.g., increased intracranial or intraocular pressure) * Pregnancy * Emergency surgery * Beard (preventing adequate face mask seal) * Previous gastric surgery * Inability to visualize the gastric antrum by ultrasonography
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Time to reach an end-tidal oxygen concentration (EtO₂) of 90% | Periprocedural (during the preoxygenation period, prior to induction of anesthesia) | The time, in seconds, from the start of preoxygenation until the end-tidal oxygen concentration (EtO₂) reached 90%. End-tidal oxygen was measured at 30-second intervals using the anesthesia machine gas analyzer. Reaching EtO₂ 90% was defined as the endpoint of the preoxygenation period. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Heart rate | Periprocedural (baseline and pre-induction) | Heart rate was measured at baseline (before the start of preoxygenation) and at the end of the preoxygenation period, defined as the time point when end-tidal oxygen concentration (EtO₂) reached 90%. |
| Gastric antral cross-sectional area | Periprocedural (baseline and pre-induction) | Gastric antral cross-sectional area measured by ultrasonography using a 2-5 MHz convex probe, calculated as (anteroposterior diameter × craniocaudal diameter × π)/4. Measurements were performed at baseline (before the start of preoxygenation) and at the completion of the preoxygenation period, defined as the time point when end-tidal oxygen concentration (EtO₂) reached 90%. |
| Gastric distension score | Periprocedural (baseline and pre-induction) | Epigastric gastric distension assessed using a 4-point ordinal scale (0 = none, 1 = mild, 2 = moderate, 3 = marked). The score was recorded at baseline (before the start of preoxygenation) and at the completion of the preoxygenation period, defined as the time point when end-tidal oxygen concentration (EtO₂) reached 90%. |
| Reflux, belching, and discomfort | Periprocedural (baseline and pre-induction) | Patient-reported occurrence of discomfort, symptomatic gastroesophageal reflux, or belching during the preoxygenation period. Events were assessed and recorded at the completion of the preoxygenation period, defined as the time point when end-tidal oxygen concentration (EtO₂) reached 90%. |
| Systolic Blood Pressure | Periprocedural (baseline and pre-induction) | Systolic blood pressure measured noninvasively at baseline (before the start of preoxygenation) and at the completion of the preoxygenation period, defined as the time point when end-tidal oxygen concentration (EtO₂) reached 90%. |
| Diastolic Blood Pressure | Pre-induction (baseline and at completion of preoxygenation, defined by EtO₂ reaching 90%) | Diastolic blood pressure measured noninvasively at baseline (before the start of preoxygenation) and at the completion of the preoxygenation period, defined as the time point when end-tidal oxygen concentration (EtO₂) reached 90%. |
| Peripheral Oxygen Saturation (SpO₂) | Periprocedural (baseline and pre-induction) | Peripheral oxygen saturation (SpO₂) measured at baseline (before the start of preoxygenation) and at the completion of the preoxygenation period, defined as the time point when end-tidal oxygen concentration (EtO₂) reached 90%. |
Countries
Turkey (Türkiye)
Outcome results
None listed