Hunger and thirst numeric rating scales are not valid estimates for gastric content volumes: a prospective investigation in healthy children.
OBJECTIVE
A rating scale for thirst and hunger was evaluated as a noninvasive, simple and commonly available tool to estimate preanesthetic gastric volume, a surrogate parameter for the risk of perioperative pulmonary aspiration, in healthy volunteer school age children.


METHODS
Numeric scales with scores from 0 to 10 combined with smileys to rate thirst and hunger were analyzed and compared with residual gastric volumes as measured by magnetic resonance imaging and fasting times in three settings: before and for 2 h after drinking clear fluid (group A, 7 ml/kg), before and for 4 vs 6 h after a light breakfast followed by clear fluid (7 ml/kg) after 2 vs 4 h (crossover, group B), and before and for 1 h after drinking clear fluid (crossover, group C, 7 vs 3 ml/kg).


RESULTS
In 30 children aged 6.4-12.8 (median 9.8) years, participating on 1-5 (median two) study days, 496 sets of scores and gastric volumes were determined. Large inter- and intra-individual variations were seen at baseline and in response to fluid and food intake. Significant correlations were found between hunger and thirst ratings in all groups, with children generally being more hungry than thirsty. Correlations between scores and duration of fasting or gastric residual volumes were poor to moderate. Receiver operating characteristic (ROC) analysis revealed that thirst and hunger rating scales cannot predict gastric content.


CONCLUSIONS
Hunger and thirst scores vary considerably inter- and intra-individually and cannot predict gastric volume, nor do they correlate with fasting times in school age children.
Department of Anesthesia, University Children's Hospital, Zurich, Switzerland.
Sabin
S
Buehrer
Ursula
U
Hanke
Richard
R
Klaghofer
Melanie
M
Fruehauf
Markus
M
Weiss
Achim
A
Schmitz
D002648:Child; D018592:Cross-Over Studies; D004326:Drinking; D004435:Eating; D005215:Fasting; D005260:Female; D005766:Gastrointestinal Contents; D006801:Humans; D006815:Hunger / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D011446:Prospective Studies; D063466:Respiratory Aspiration of Gastric Contents / Q000175:diagnosis / Q000503:physiopathology; D018570:Risk Assessment; D013270:Stomach / Q000502:physiology*; D013894:Thirst / Q000502:physiology*
child; fasting; hunger; preoperative care; respiratory aspiration of gastric contents; thirst