Preoperative fasting does not affect haemodynamic status: a prospective, non-inferiority, echocardiography study.
BACKGROUND
The link between preoperative fasting and hypovolaemia remains unclear. We tested the hypothesis that preoperative fasting does not significantly increase the proportion of patients with hypovolaemia according to transthoracic echocardiography (TTE) criteria.


METHODS
Patients of ASA status I-III and without bowel preparation were included in a non-inferiority, prospective, single-centre trial. Patients underwent passive leg raising (PLR) test and TTE at admission (Day 0) and after 8 h fasting (Day 1). The primary hypothesis was that an 8 h preoperative fasting does not increase the proportion (margin=5%) of patients with a positive PLR test ('functional approach'). The secondary hypothesis was that echocardiographic filling pressures or stroke volume (margin 10%) are not affected by preoperative fasting ('static approach').


RESULTS
One hundred patients were included and 98 analysed. After an 8 h fasting, the change in the proportion of responders to PLR was -6.1% [95% confidence interval (CI)=-16.0 to 3.8] of responders to PLR test on Day 0 when compared with Day 1. Because 95% CI was strictly inferior to 5%, there was no significant increase in the proportion of PLR responders on Day 1 when compared with Day 0. The 95% CI changes of static variables were always fewer than 10%, meaning that preoperative fasting induced significantly no relevant changes in static variables.


CONCLUSIONS
Preoperative fasting did not alter TTE dynamic and static preload indices in ASA I-III adult patients. These results suggest that preoperative fasting does not induce significant hypovolaemia. Clinical trial registration NCT 01258361.
Department of Anesthesiology, Critical Care, Emergency, and Pain, Division Anesthésie Réanimation Douleur Urgences, Centre hospitalier universitaire Caremeau, Place du Pr Debré. 30029 Nîmes, France.
L
L
Muller
M
M
Brière
S
S
Bastide
C
C
Roger
L
L
Zoric
G
G
Seni
J-E
JE
de La Coussaye
J
J
Ripart
J-Y
JY
Lefrant
D004452:Echocardiography / Q000379:methods*; D005215:Fasting / Q000502:physiology*; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D020896:Hypovolemia / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care / Q000379:methods*; D011446:Prospective Studies; D013318:Stroke Volume / Q000502:physiology
blood volume; echocardiography; fasting