Effect of Intravenous Metochlopramide Prophylaxis on Gastric Volume
Condition: Aspiration Prophylaxis
Study type: Observational

Summary: 
      Gastric fluid volume and pH in patients undergoing cesarean section are essential
      considerations for general anesthesia (GA). Increased gastric volume and low pH of gastric
      contents could predispose the risk of aspiration pneumonitis. The present study explored the
      research question "whether prophylaxis with intravenous metoclopramide significantly reduces
      gastric volume and antral cross-sectional area in patients awaiting cesarean section under GA
    

Detailed description: 
      Since regional anaesthesia has largely replaced general anaesthesia, the risk of aspiration
      pneumonitis during caesarean sections has significantly decreased. Nevertheless, prophylaxis
      against gastric aspiration is still important in patients in whom regional anaesthesia is
      contraindicated or in whom general anaesthesia has to be administered (for example; during
      emergency caesarean delivery). The administration of intravenous anaesthetics reduces the
      level of consciousness of a patient that compromises the protective reflexes of the upper
      airways. Moreover, a high level of sedation also reduces the tone of the LES (lower
      oesophageal sphincter). Both these situations predispose the risk of aspiration pneumonia in
      patients awaiting surgical interventions in supine position under general anaesthesia.

      The risk of aspiration increases in outpatients if the volume of the gastric contents
      increases beyond 25 ml and its pH falls below 2.5. However, the risk of aspiration
      significantly decreases in "fasted" outpatients. Since most patients awaiting elective
      surgery remains fasted, routine prophylaxis for preventing aspiration pneumonitis is not
      recommended anymore.

      the administration of intravenous metoclopramide and cimetidine across patients (n=20)
      awaiting laparoscopic gynaecological surgery significantly increased the pH of the gastric
      contents in the intervention group compared to their control counterparts (6.1 versus 2.7,
      p<0.05). The mean aspirated volumes were also significantly lower in the intervention group
      compared to their age-matched controls (6.9ml versus 15.3ml, p<0.05). Hong (2006) further
      showed that the percentage of individuals with high-risk gastric volume (>25 ml) and low pH
      (<2.5) was higher in individuals who did not receive intravenous metoclopramide and
      cimetidine prior to surgery compared to their counterparts who received such interventions
      (20% versus 5%, p<0.05) .
    

Intervention name(s): Abdominal ultrasound evaluation of antral area
Intervention type(s): Diagnostic Test
Intervention description(s): ultrasound assessment of antral cross sectional area
Other intervention name(s): Nausea and vomiting episodes
Observational model: Case-Control
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        pregnant females
      
Keywords: metoclopramide; cesarean section; ultrasound; gastric volume