Canadian Journal of Anaesthesia

, Volume 38, Issue 4, pp 425–429 | Cite as

Gastric fluid volume and pH in elective patients following unrestricted oral fluid until three hours before surgery

  • J. R. Maltby
  • P. Lewis
  • A. Martin
  • L. R. Sutherland
Reports of Investigation

Abstract

This clinical study was designed to assess the results of new preoperative fasting guidelines in which patients are instructed that they must not eat any solid food after midnight, but that they may drink unrestricted amounts of clear fluid until three hours before their scheduled time of surgery. We studied 199 healthy, elective surgical inpatients aged 18– 70 yr to determine whether there was any corrélation between the ingestion interval or the volume of fluid ingested, with the volume and pH of residual gastric fluid at induction of anaesthesia. Pregnant patients, and those with gastric disorders or who were taking medications that affect gastric motility or secretion, were excluded. Either no premedication was given, or oral diazepam 5– 15 mg was given 90 min preoperatively. Of the 199 patients, 105 ingested 50– 1200 ml on the morning of surgery. The ingestion-induction interval was less than three hours in 12 patients whose actual surgery time was ahead of schedule. The remaining 94 patients did not drink because they were scheduled for surgery before 11:00 (n = 51), they did not want to drink (n = 24), or they were advised not to drink by their nurse or surgeon (n = 16). Following induction of anaesthesia, gastric fluid was aspirated through a #18 Salem sump orogastric tube, the volume was recorded and pH was measured with à calibrated pH meter. Patients were divided retrospectively into four groups (in three of which patients ingested fluid) according to the ingestion-induction interval (1.3– 3.0 hr, 3.1– 5.0 hr, 5.1– 8.0 hr, and nothing by mouth after midnight). Values (mean ± SD) for residual gastric fluid volume (22 ± 19, 32 ± 26, 28 ± 19, 25 ± 19 ml) and pH (1.5 ± 0.3, 1.7 ± 1.3, 1.6 ± 1.1, 1.6 ± 0.9) showed no statistically significant differences among the four groups. Within each of the three fluid groups there was no correlation between volume of fluid ingested and residual gastric fluid volume. We conclude that healthy inpatients should be allowed to ingest unrestricted clear fluid until three hours before the scheduled time of surgery.

Key words

anaesthesia: adult complications: aspiration, prophylaxis gastrointestinal tract: gastric emptying, gastric pH, gastric volume, preoperative fluids 

Résumé

Cette étude clinique fut conçue ofin d’évaluer les résultats des nouvelles directives de jeune préopératoire par lequel les patients sont informés de ne pas ingérer de nourriture solide après minuit mais qu’ils peuvent boire line quantize limitee de liquide clair jusqu’à trois heures avant le temps cédule de la chirurgie. On à étudié 199 patients en bonne santé devant subir une chirurgie élective âgés de 18 à 70 ans afin de determiner s’il y avail une corrélation entre iintervalle de l’ingestion ou le volume de liquide ingéré avec le volume el le pH du liquide gastrique résiduel à l’induction de l’anesthésie. Les patientes enceintes et ceiix ayant des problèmes gastriques on ceux qui prenaient des médicaments pouvant affecter la motilite ou la secretion gastrique furent exclus. En période préopératoire, aucune prémédication ne fut donnée ou du diazépam par voie orale 5– 15 mg fut administré 90 minutes avant l’opération. Des 199 patients, 105 out ingéré 50– 1200 ml le matin de la chirurgie. L’intervalle entre l’ingestion et l’induction fut moins que trois heures chez douze patients chez qui le temps réel de la chirurgie était en avarice de la cedule. Les 94 autres patients n’avaient pas bit car la cédule de leur chirurgie était avant 11 heures(n = 51), ou qu’ Us n’ avaient pas envie de boire (n = 24), ou ils furent avisés de s’abstenir de boire par l’ infirniière ou les chirurgiens (n = 16). Aprés l’induction de l’anesthésie, le liquide gastrique fut aspiré à trovers un tube orogastrique #18 Salem, le volume fut enregistré el le pH fut mesuré. Les patients furent divisés d’une façon rétrospective en quatre groupes (trois de ce groupe de patients ont ingéré du liquide) selon l’ intervalle d’ingeslion-induction (1,3–3,0 heiire, 3,1–5,2 heure, 5,1–8,0 heure, et aucune ingestion orole après minuit). Les valeurs (moyenne ± SD) pour le volume du liquide gastrique residue! (22 ± 19,32 ± 26,28 ± 19,25 ± 19 ml) à le pH (I,5 ± 0,3, 1,7 ± 1,3, 1,6 ± 1,1, 1,6 ± 0,9) n’a pas demontre de difference stotistiquement significaiive entre les quatre groupes. Entre les groupes de patients ayant ingéré des liquides, il n’y avail aucune corrélation entre le volume des liquides ingeres et le volume du liquide gastrique résiduel. On conclut que les patients hospitalises en bonne santé doivent etre autorisés à absorber sans restriction du liquide clair jusqua trois heures avant le temps cédulé de la chirurgie.

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Copyright information

© Canadian Anesthesiologists 1991

Authors and Affiliations

  • J. R. Maltby
    • 1
  • P. Lewis
    • 1
  • A. Martin
    • 1
  • L. R. Sutherland
    • 2
  1. 1.Department of AnaesthesiaFoothills Hospital at The University of CalgaryCalgary ABCanada
  2. 2.Department of MedicineFoothills Hospital at The University of CalgaryCanada

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