Clinical trial NCT06861569: Effect of Positive End-expiratory Pressure on the Gastric Volume
Official title: Effect of Positive End-expiratory Pressure on the Gastric Volume in Patients Undergoing General Anesthesia with Supraglottic Airway Device: a Prospective Randomized Controlled Non-inferiority Trial
Study type: INTERVENTIONAL
Overall status: NOT_YET_RECRUITING
Phase: NA
Conditions: Gastric Volume
Breast Cancer Female
Anesthesia Complication
Keywords: Supraglottic Airway Device
Postive End Expiratory Pressure
Gastric Sonography
Lead sponsor: Seoul National University Bundang Hospital
Sponsor class: OTHER
First posted: 2025-03-06
Enrollment: 128
Sex: ALL
Minimum age (years): 19
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: OTHER

Brief summary: The main purpose of this study is to quantitatively evaluate the effect of applying PEEP during the use of SGA on gastric volume, aiming to provide objective evidence regarding the potential side effects, such as gastric volume increase. It is expected that this will contribute to improving the quality of patient management through the safe clinical use of SGA and PEEP.

Detailed description: General anesthesia has positive effects in relieving pain and unpleasant memories during surgery by blocking the patient's voluntary movements and reflexes to stimuli. However, it can lead to side effects such as severe impairment or absence of spontaneous breathing, necessitating artificial respiration. Among the conventional airway management methods for artificial respiration, the supraglottic airway device (SGA) has the advantage of reducing hemodynamic changes, intracranial pressure, and intraocular pressure caused by airway stimulation, as it does not pass through the airway, and it reduces airway-related complications. However, a disadvantage is its inability to adequately seal the airway, making it difficult to use in cases where there is a high risk of aspiration or when high airway pressures are required.

Positive End Expiratory Pressure (PEEP) has the advantage of preventing atelectasis, improving oxygen exchange capacity, and preventing pulmonary complications by maintaining lung expansion. However, applying PEEP increases airway pressure, and if the SGA does not adequately seal the airway, there is a possibility of air entering the stomach. If air enters the stomach and increases gastric volume, the risk of postoperative vomiting and aspiration pneumonia increases due to increased gastric pressure. Also, increased intra-abdominal pressure and diaphragmatic elevation can lead to respiratory distress due to decreased lung volume during postoperative recovery.

While there are studies suggesting that PEEP can be safely used with SGA, there is a need for verification as there are no studies objectively measuring changes in gastric volume using methods such as ultrasound when using PEEP with SGA. The main purpose of this study is to quantitatively evaluate the effect of applying PEEP during the use of SGA on gastric volume, aiming to provide objective evidence regarding the potential side effects, such as gastric volume increase. It is expected that this will contribute to improving the quality of patient management through the safe clinical use of SGA and PEEP.

Before entering the operating room, patients will be placed in a sitting and right lateral decubitus (RLD) position to measure the cross sectional area(CSA) of the stomach antrum using ultrasound. One investigator will scan the sagittal plane in the upper abdominal region using a low-frequency ultrasound probe (2-5 MHz) and measure the major diameter (D1) and transverse diameter (D2) of the observed antrum. CSA can be calculated from the measured values as in formula (a) below. The investigator will scan three times for each posture, and calculate the average.

CSA = D1 x D2 x 1/4 ------- (a) Using CSA, gastric volume (GV) is estimated using formula (b) below. GV (ml) = 27.0 + 14.6 × CSA - 1.28×age ------- (b) Midazolam premedication is not administered before surgery. When patients enter the operating room, standard monitoring devices (electrocardiogram, pulse oximetry, non-invasive blood pressure monitor, BIS or SedLine) are attached for vital sign monitoring, and target-controlled infusion of propofol is initiated at a target concentration of 4.0 µg/ml, and remifentanil at a target concentration of 3.0 ng/ml.

After confirming loss of consciousness and loss of spontaneous respiration, SGA is inserted, and the position of the SGA is evaluated and recorded using the fiberoptic scoring system.

During surgery, maintenance of anesthesia is managed with target-controlled infusion of propofol to keep BIS (Bispectral Index) between 40-60 or PSI (Patient State Index) between 25-49. For adequate analgesia during surgery, remifentanil is continuously infused using target-controlled infusion.

At 5 minutes (T0), 30 minutes (T1), and 60 minutes (T2) after SGA insertion, the following values related to mechanical ventilation are measured: FiO2 (Fraction of Inspired Oxygen), PIP (Peak Inspiratory Pressure), RR (Respiratory Rate), lung compliance, SpO2 (Oxygen Saturation), EtCO2 (End-tidal Carbon Dioxide), TV (Tidal Volume), OLP (Oropharyngeal Leak Pressure), leak volume, and leak fraction.

Immediately after surgery, CSAright-lat and GV are measured as described in above. After confirming that respiration and consciousness levels have returned to clinically normal conditions post-surgery, the patient is discharged to the recovery room, and assessments are made for nausea or vomiting, respiratory depression, sore throat, and blood staining.

Eligibility criteria: Inclusion Criteria:

* Adult patients aged 19 and above.
* Patients scheduled for general anesthesia for elective surgery.
* American society of anesthesiologists physical status classification 1 or 2

Exclusion Criteria:

* Individuals who have not provided prior consent for participation in the study
* Patients showing cognitive impairment to the extent that voluntary consent is difficult
* Obesity with a BMI of 30 kg/m² or higher
* Patients with anatomical abnormalities in the airway structure making supraglottic airway device application difficult
* Patients with respiratory diseases making PEEP application difficult (e.g., chronic obstructive pulmonary disease, asthma)
* Patients suspected of delayed gastric emptying (e.g., not adhering to fasting guidelines, medication use affecting gastric motility \[anticholinergics, narcotic analgesics\], neurological disorders \[Parkinson's disease, multiple sclerosis\], diabetes, hypothyroidism)
* Patients with a history of gastrointestinal surgery
* Pregnant women
* Patients undergoing concurrent surgeries or collaborative procedures
* Patients transferred from the intensive care unit

Primary outcomes:
measure: Gastric volume difference before and after surgery
timeFrame: Baseline and end of surgery 0 minute
Secondary outcomes:
measure: Fraction of Inspired Oxygen
timeFrame: 5 minutes, 30 minutes, 60 minutes after SGA insertion
measure: Peak Inspiratory pressure
timeFrame: 5 minutes, 30 minutes, 60 minutes after SGA insertion
measure: Respiratory rate
timeFrame: 5 minutes, 30 minutes, 60 minutes after SGA insertion
measure: Lung compliance
timeFrame: 5 minutes, 30 minutes, 60 minutes after SGA insertion
measure: Oxygen Saturation
timeFrame: 5 minutes, 30 minutes, 60 minutes after SGA insertion
measure: End-tidal carbon dioxide
timeFrame: 5 minutes, 30 minutes, 60 minutes after SGA insertion
measure: Tidal volume
timeFrame: intraoperative period
measure: Oropharyngeal leak pressure
timeFrame: 5 minutes, 30 minutes, 60 minutes after SGA insertion
measure: Leak volume and leak fraction
timeFrame: 5 minutes, 30 minutes, 60 minutes after SGA insertion
measure: Presence of blood staining on SGA
timeFrame: Immediately after the end of anesthesia
measure: The duration of stay in the recovery room after surgery
timeFrame: upto 1 hour after entering the recovery room
measure: Presence of postoperative nausea and vomiting
timeFrame: upto 1 hour after entering the recovery room
measure: Presence of respiratory depression
timeFrame: upto 1 hour after entering the recovery room
measure: Presence of sore throat
timeFrame: upto 1 hour after entering the recovery room
Other outcomes:
Locations:
Study officials:
affiliation: Seoul National University Bundang Hospital
name: Bon Wook Koo
role: STUDY_CHAIR
References: