Gastric fluid volume pH, and emptying in elective inpatients Influences of narcoticatropine premedication oral fluid, and ranitidine

Abstract

One hundred and twenty healthy, elective surgical inpatients were randomly assigned to one of four groups. Between two and three hours before the scheduled time of surgery all patients ingested a marker dye, phenol red, 50 mg in 10 ml water, with placebo tablet alone (Groups 1 and 2), placebo tablet with 150 ml oral fluid (Group 3), or oral ranitidine 150 mg with oral fluid 150 ml (Group 4). Patients in Group 1 received oral diazepam or no premedication, while those in Groups 2, 3, and 4 received IM narcotic and atropine one hour preoperatively. Following induction of anaesthesia the residual gastric fluid was aspirated through a Salem sump tube and its volume, pH, and phenol red content measured. Mean volumes were Group 1: 24 ml; Group 2: 13 ml; Group 3: 17 ml; Group 4: 14 ml. Mean pH values were Group 1: 2.99; Group 2: 3.03; Group 3: 3.44; Group 4: 5.28. The amount of phenol red in the samples indicated at least 90 per cent gastric emptying had occurred in 90 per cent of patients. We conclude that, in healthy patients, 150 ml oral fluid is almost completely emptied from the stomach within two hours of ingestion, even when followed one hour later by narcotic-atropine premedication.

Pre‐operative fasting guidelines: an update

“…Up to 150 ml of water together with oral medication up to 1 h before induction of anaesthesia is perfectly safe in adults (42). Based on the prolonged gastric emptying seen with the use of opiates, it is reasonable to stop fluid intake 1 h before the use of opiate premedication (49).…”

Assessment of Pre-Gastroscopy Fasting Period Using Ultrasonography

“…Gastric emptying depends on the amount of fluid ingested and the osmotic pressure of the beverage [1,16,17]. The gastric passage of fluids containing fat such as milk is slower than the passage of clear fluids containing glucose, thus leading to a minimal 3 h fasting period after the consumption of milk [18], which is also considered too short by some anaesthesiologists [19].…”

Pr�operative Nahrungskarenz

“…Tatsächlich berichten Untersuchungen an elektiven, chirurgischen Patienten der ASA-Klasse I-II [27,28,54,55] sowie der ASA-Klasse I-III [42] von durchschnittlichen gastralen Residualvolumina in den Grenzen von 10-30 ml trotz der Verabreichung klarer Flüssigkeit in einem Zeitraum von 1-2 h vor der Narkoseeinleitung. Allerdings stellen Patienten mit nicht diagnostizierter Magenfunktionsstörung und funktionaler Dyspepsie zu bedenkende Ausnahmen dar, die z. T. Magenrestflüssigkeit in Mengen bis 200 ml aufweisen können [5,20].…”

“…Mehrere randomisierte und kontrollierte Studien [1,26,27,28,42,54] sowie Metaanalysen [2,55] mit Patienten (ASA I-III), die für elektive Operationen vorgesehen waren, haben gezeigt, dass die orale Gabe von Wasser und anderen klaren Flüssigkeiten (Tee, Kaffee, Mineralwasser,Apfel-und fruchtfleischlosem Orangensaft) bis zu 2 h vor Narkoseeinleitung weder das Flüssigkeits-volumen im Magen erhöhen noch den Magen pH-Wert senken. Daher ist aus unserer Sicht das Risiko einer Aspirationspneumonie nach Erbrechen oder Regurgitation gegenüber der Situation komplett fastender Patienten als nicht erhöht anzusehen [23].…”