202410281955

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Gastric emptying in pregnancy

In 1946, Mendelson described the association between the pulmonary aspiration of gastric contents and the occurrence of respiratory complications in 66 patients, most of whom delivered vaginally under ether and nitrous oxide anaesthesia

Risk factors of aspiration:

• patient
  • delayed gastric emptying
• surgical
  • length of surgery
  • patient position
• anaes
  • gastric insufflation
  • difficult tracheal intubation
  • inadequate depth of anaesthesia

Other risk factors in pregnancy:

• decreased gastric pH,
• the effect of the gravid uterus on abdominal pressure
• progesterone-mediated relaxation of the lower oesophageal sphincter

global interest in the ‘Sip-Til-Send’ initiative has enabled them to drink sips of water only until they are called for to surgery. It has decreased the incidence of nausea and vomiting, light headedness, and thirst, increased comfort, and reduced the rate of anxiety in women

Studies that evaluate gastric emptying use different methods such as

• #Gastric ultrasound
• #Paracetamol absorption
• scintigraphy

Gastric ultrasound

nonpregnant / in T1 / postpartum: supine and right lateral position
T2 and T3: right lateral semirecumbent and semirecumbent position

The right lateral semirecumbent and semirecumbent position are preferred in pregnancy to avoid the effect of supine aortocaval compression

Paracetamol absorption

If administered orally, paracetamol is absorbed poorly in the stomach but well in the duodenum and proximal jejunum

Given that gastric emptying is hence the rate-limiting step in the delivery of the drug to its absorption site, the speed of paracetamol absorption into the blood indirectly reflects the rate of gastric emptying

The area under plasma paracetamol curve and peak plasma paracetamol concentration are proportional and the time to peak paracetamol concentration is inversely proportional to the rate of gastric emptying

References