To study the effect of prokinetic enhanced two-hour fasting versus overnight fasting on pre-operative gastric residual volume and pH in patients undergoing elective surgeries under general anaesthesia.

Brief Description of the Proposal

Introduction: Pulmonary aspiration of gastric contents is a potentially life-threatening

complication during anesthesia, particularly during induction. To minimize this risk, preoperative fasting

or “nil per os” (NPO) guidelines are universally followed to ensure an empty stomach at the time of

anesthesia. The American Society of Anesthesiologists (ASA) recommends minimum fasting periods of 2

hours for clear liquids and 6 to 8 hours for light and heavy meals, respectively. However, these guidelines

are generalized and may not adequately reflect individual variability in gastric emptying influenced by

age, metabolic rate, comorbidities, stress, and type of ingested food.

Despite adherence to fasting guidelines, residual gastric contents may still be present in some

patients, posing a risk of regurgitation and aspiration during induction. In clinical practice,

anesthesiologists often face uncertainty regarding gastric emptiness, especially when fasting history is

unreliable or surgical schedules change unexpectedly. In such scenarios, a non-invasive and reliable

method to assess gastric content can be of immense clinical value.

Ultrasonography (USG) has emerged as a safe, rapid, and non-invasive bedside tool for

evaluating gastric volume and content. It allows real-time visualization of the gastric antrum and helps

determine whether the stomach is empty, contains clear fluids, or solids. By providing both qualitative

and quantitative data, gastric ultrasound can help guide anesthesia management decisions and enhance

perioperative safety.

It’s well known that inhaling stomach contents into the lungs (gastric aspiration) can lead to

serious health problems and even death in some cases. Severity of the complication depends on both the

volume of content and what it’s made of—solid or particulate matter is especially dangerous.

To reduce the risk of aspiration during anesthesia, the American Society of Anesthesiologists

(ASA) recommends fasting before surgery to ensure the stomach is empty. However, this guideline

doesn’t always apply in emergency situations. The ASA’s fasting recommendations are based on multiple

meta-analyses of randomized clinical trials (RCTs) that compare stomach contents in patients who fasted

for 2–4 hours versus those who fasted for longer than 4 hours.

These studies show that the risk of aspiration is lower when the stomach volume is less than 25

ml and the pH is greater than 2.5. This typically occurs when patients are allowed to drink clear liquids up

to 2–4 hours before anesthesia.

The study in question was designed to measure stomach volume and acidity (pH) in two groups

of patients: one group that fasted for only two hours after taking a prokinetic (a drug that speeds up

stomach emptying), and another group that fasted overnight. All patients were scheduled for elective

(non-emergency) procedures.

Aim: To find out the actual trends of gastric volume and pH in patients with two hour fasting with a

prokinetic drug versus overnight fasting who are undergoing elective surgical procedures.

Objectives:

Primary:

1. To assess residual gastric volume and pH using ultrasonography in patients fasted overnight

before and fasted for 2 hour with prokinetic agent prior to elective surgery.

Secondary:

1. To compare the gastric volume after overnight fasting and 2 hour fasting with prokinetic agent.

2. To correlate gastric pH after overnight fasting and 2 hour fasting with prokinetic agent

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3. To evaluate the effectiveness of current fasting guidelines in ensuring safe gastric emptying.

Justification: Study can justify and compare newer enhanced fasting guideline practiced with

conventional prolonged fasting guidelines.

Methodology:

Study design: The study will be a clinical multicentric observational study to be done in Superspeciality

Hospital, NSCB Govt. Medical College, Jabalpur.

Inclusion criteria:

1. Adult patients aged 18–60 years

2. ASA physical status I or II

3. Scheduled for elective surgery under general anesthesia

4. Provided informed written consent.

Exclusion criteria:

1. Patient refusal

2. Emergency surgeries

3. Patients with known gastrointestinal disorders (e.g., GERD, gastroparesis)

4. Obese patients (BMI > 35 kg/m²)

5. Pregnant patients , Diabetes Mellitus , gastric surgery.

6. Patients on medications affecting gastric motility

7. Patient on TCA treatment

Subject recruitment:

Total 90 patients will be recruited who are being posted for elective surgery under general anesthesia,

who will be randomized into Group A or Group B randomly alternatively.

Pre operative preparation:

• All patients will be subjected to a detailed history, thorough physical examination and systemic

examination prior to the surgery.

• Basic demographic data including age, height and weight will be recorded.

• Routine investigations and any specific tests if indicated will be done .

• Patients will be explained in detail about the USG screening procedure.

• Informed consent will be taken.

• monitors like Pulse Oximetry, Non invasive BP, and ECG will be connected

• Baseline values of HR, BP, SPO2 will be recorded.

• IV access will be secured.

Patients will be allocated randomly into two groups :

Group A ( n = 45 ) : patients with overnight fasting prior to surgery

Group B ( n= 45 ) : patients with 2 hour fasting for clear liquids receiving 10 mg Metoclopramide IV.

Gastric volume will be measured using a portable BPL Alpinion ECUBE 8 ultrasound machine, and

the scans will be performed by the anesthesia team. For the scan, patients will be placed in the Right

Lateral Position (RLP). A 3–5 MHz abdominal ultrasound probe will be used to view the gastric antrum.

The antrum will be appeared as a round or oval shape located between the left lobe of the liver in front

and the pancreas behind, when the probe will be placed vertically (in the sagittal plane) over the upper

abdomen (epigastric region). If the stomach is empty, the antrum will look flat with its front and back

walls touching. If there is food or fluid inside, the antrum will appear distended or showed movement

(peristalsis)

Measurements :-

Antral Cross-Sectional Area (CSA):

This area was calculated using the formula:

where D1 is the front-to-back diameter and D2 is the top-to- bottom diameter of the antrum.

Gastric Residual Volume (GRV):

To estimate the amount of content in the stomach, the following formula (from Perlas et al.) was used:

.

Ultrasound timing:

On OT table, just prior to Anaestheisa induction

pH Measurement:

Stomach fluid will be collected by gently suctioning it out using a 20 mL syringe attached to an 18 French

Ryle’s tube (a type of nasogastric tube), which is inserted after the patient is under anesthesia. The acidity

(pH) of the stomach contents will be checked using pH paper strips.