Intraoperative opioid versus non-opioid induced delay in perioperative gastric emptying: A comparative randomised double blind controlled study

Analgesics are widely prescribed for acute and chronic pain. Opium is one of the oldest herbal

medicines currently used as an analgesic, sedative and antidiarrhoeal. The effects of opium are

principally mediated by the μ-, κ- and δ-opioid receptors. Common adverse effects of opioid

administration include sedation, dizziness, nausea, vomiting, delayed gastric emptying,

constipation, dependency and tolerance, and respiratory depression.

Most of their effects on gastrointestinal motility and secretion result from suppression of neural

activity. Inhibition of gastric emptying, increase in sphincter tone, changes in motor patterns, and

blockage of peristalsis result from opioid use. Sedation and general anaesthesia depress or

impede the physiological mechanisms that protect against aspiration (the tone of the lower

oesophageal sphincter and upper airway reflexes).

Although the detrimental effects of opioids on the lower gastrointestinal tract are well known,

the opioid health crisis has certainly brought this to the forefront of gastroenterology with recent

data regarding their impact on esophageal and gastroduodenal motility. Aspiration of gastric

contents is a rare but nevertheless important cause of anaesthetic mortality and morbidity. It is

recognised that opioids can delay gastric emptying and the use of these drugs may increase the

risk of peri-operative aspiration of gastric contents. The delay in gastric emptying may also

reduce the effectiveness of oral analgesics given postoperatively

.

Opiod-free anaesthesia is now a new favourite of anaesthesiologists in journals and in

conferences as a topic of lecture, symposium and panel discussion. However, assessment of

perioperative gastric contents relies almost exclusively on clinical history that may not be

reliable. Older studies have done assessment of perioperative gastric volume by other techniques

such as acetaminophen absorption test, electrical bioimpedance technique, scintigraphy, etc

.

Nowadays, there is a growing interest in the use of bedside ultrasonography to assess gastric

contents and volume. The ISA national preoperative guidelines weakly recommend gastric

ultrasound as a bedside tool for assessing the quality and quantity of gastric contents in the

preoperative period

. The current study will evaluate the intraoperative opioid versus non-

opioid induced delay in perioperative gastric emptying using gastric ultrasound as a bedside tool.