The effect of preoperative oral fluid and ranitidine on gastric fluid volume and pH

  • A. D. Sutherland
  • J. Roger Maltby
  • J. P. Sale
  • Crawford R. G. Reid


One hundred unpremedicated daycare patients were randomly assigned to one of four groups. Between two and three hours preoperatively all patients received either oral ranitidine 150 mg, or placebo, with bromosulphthalein (BSP) 50 mg in JO ml water, immediately followed by either ISO ml water or no further fluid.

The residual gastric volume (RGV) in the two placebo groups was significantly lower in patients given 150 ml water (20.6 ± 14.1 ml) than in those who continued fasting (29,9 ± 18.2 ml) (p <0.05). The RGV was further significantly decreased in the two ranitidine groups (10.0 ± 8.8, 9.7 ± 10.5ml) compared with the two placebo groups (20.6 ± 14.1, 29.9 ± 18.9 ml) (p <0.01).

Mean pH values were significantly higher in the two ranitidine groups (6.71 ± 0.99; 6.31 ± 1.81) than in the two placebo groups (2.05 ± 1.41; 1.72 ± 0.33) but were not significantly different in the fluid versus non-fluid groups. In patients who ingested 150 ml water there was no correlation between the premedication interval and either RGV or pH values. The extremely low percentage of the original BSP ( <0.9 per cent) in the gastric fluid of these patients demonstrated that gastric emptying of the ingested water was virtually complete prior to surgery.

The combination of RGV of 25 ml or more with pH less than 2.5 was present in 56 per cent of patients who had only a sip of water with placebo, in 28 per cent of those who received 150 ml water with placebo, and in only two per cent of those patients who received ranitidine.

Key words

anaesthesia outpatient histamine H2 receptor blockers ranitidine gastrointestinal tract stomach gastric emptying 


Cent patients externes ont été randomisés en quatre groupes. Entre la première et la troisième heure pré-op, tous les patients ont reçu avec de la bromosulphthalein (BSP) (50 mg dans 10 ml ďeau) soit de la ranitidine 150 mg soit du placebo. Ceci fut suivi immédiatement soit par ľingestion de 150ml ďeau soit par aucune ingestion de liquide.

Le volume gastrique résiduel (RGV) dans les deux groupes placebo étaient significativement plus bas chez les patients ayant reçu 150ml ďeau (20.6 i 14.1ml) que ceux qui sont restés a jeun (29.9 ±18.2ml)(p < 0.05). Le RGV était encore plus significativement diminué dans les deux groupes ranitidine (10.0 ±8.8, 9.7 ± 10.5 ml) comparativement aux deux groupes placebo (20.6 ± 14.1, 29.9 í 8.9) (p < 0.01).

Les valeurs moyennes du pH étaient significativement plus élevées dans les groupes ranitidine (6.71 ± 0.99; 6.31 ± 1.81) que dans les deux groupes placebo mais n’étaient pas significativement différentes dans les deux groupes fluides versus groupe à jeun. Pour les patients ayant pris 150 ml ďeau il n’y avait aucune corrélation entre ľintervalle de la prémédication et soit la RGV ou les valeurs du pH. Le pourcentage extr êmement bas du BSP original (<0.9pour cent) dans le liquide gastrique de ces patients a démontré que la vidange gastrique de ľeau ingérée était presque complète avant la chirurgie.

La combinaison de RGV de 25 ml ou plus avec un pH inférieur à 2.5 était présente dans 56 pour cent des patients qui ont pris une simple gorgée ďeau avec le placebo, 20 pour cent chez ceux qui ont reçu 150 ml ďeau avec le placebo, et seulement deux pour cent chez ceux qui ont reçu la ranitidine.


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Copyright information

© Canadian Anesthesiologists 1987

Authors and Affiliations

  • A. D. Sutherland
    • 1
  • J. Roger Maltby
    • 1
  • J. P. Sale
    • 1
  • Crawford R. G. Reid
    • 1
  1. 1.Department of AnaesthesiaFoothills Hospital at the University of CalgaryCalgary, AlbertaCanada

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